forked from luck/tmp_suning_uos_patched
0eab928221
If a non-existent file is opened via O_WRONLY|O_CREAT|O_TRUNC, there's no need to treat this as a true file truncation, so we shouldn't activate the replace-via-truncate hueristic. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
5483 lines
159 KiB
C
5483 lines
159 KiB
C
/*
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* linux/fs/ext4/inode.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/inode.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Goal-directed block allocation by Stephen Tweedie
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* (sct@redhat.com), 1993, 1998
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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* 64-bit file support on 64-bit platforms by Jakub Jelinek
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* (jj@sunsite.ms.mff.cuni.cz)
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*
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* Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/time.h>
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#include <linux/jbd2.h>
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#include <linux/highuid.h>
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#include <linux/pagemap.h>
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#include <linux/quotaops.h>
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#include <linux/string.h>
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#include <linux/buffer_head.h>
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#include <linux/writeback.h>
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#include <linux/pagevec.h>
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#include <linux/mpage.h>
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#include <linux/namei.h>
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#include <linux/uio.h>
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#include <linux/bio.h>
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#include "ext4_jbd2.h"
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#include "xattr.h"
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#include "acl.h"
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#include "ext4_extents.h"
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#define MPAGE_DA_EXTENT_TAIL 0x01
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static inline int ext4_begin_ordered_truncate(struct inode *inode,
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loff_t new_size)
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{
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return jbd2_journal_begin_ordered_truncate(
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EXT4_SB(inode->i_sb)->s_journal,
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&EXT4_I(inode)->jinode,
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new_size);
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}
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static void ext4_invalidatepage(struct page *page, unsigned long offset);
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/*
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* Test whether an inode is a fast symlink.
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*/
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static int ext4_inode_is_fast_symlink(struct inode *inode)
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{
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int ea_blocks = EXT4_I(inode)->i_file_acl ?
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(inode->i_sb->s_blocksize >> 9) : 0;
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return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
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}
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/*
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* The ext4 forget function must perform a revoke if we are freeing data
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* which has been journaled. Metadata (eg. indirect blocks) must be
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* revoked in all cases.
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*
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* "bh" may be NULL: a metadata block may have been freed from memory
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* but there may still be a record of it in the journal, and that record
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* still needs to be revoked.
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*
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* If the handle isn't valid we're not journaling so there's nothing to do.
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*/
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int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
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struct buffer_head *bh, ext4_fsblk_t blocknr)
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{
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int err;
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if (!ext4_handle_valid(handle))
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return 0;
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might_sleep();
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BUFFER_TRACE(bh, "enter");
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jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
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"data mode %lx\n",
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bh, is_metadata, inode->i_mode,
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test_opt(inode->i_sb, DATA_FLAGS));
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/* Never use the revoke function if we are doing full data
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* journaling: there is no need to, and a V1 superblock won't
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* support it. Otherwise, only skip the revoke on un-journaled
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* data blocks. */
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if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
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(!is_metadata && !ext4_should_journal_data(inode))) {
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if (bh) {
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BUFFER_TRACE(bh, "call jbd2_journal_forget");
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return ext4_journal_forget(handle, bh);
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}
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return 0;
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}
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/*
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* data!=journal && (is_metadata || should_journal_data(inode))
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*/
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BUFFER_TRACE(bh, "call ext4_journal_revoke");
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err = ext4_journal_revoke(handle, blocknr, bh);
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if (err)
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ext4_abort(inode->i_sb, __func__,
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"error %d when attempting revoke", err);
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BUFFER_TRACE(bh, "exit");
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return err;
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}
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/*
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* Work out how many blocks we need to proceed with the next chunk of a
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* truncate transaction.
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*/
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static unsigned long blocks_for_truncate(struct inode *inode)
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{
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ext4_lblk_t needed;
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needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
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/* Give ourselves just enough room to cope with inodes in which
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* i_blocks is corrupt: we've seen disk corruptions in the past
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* which resulted in random data in an inode which looked enough
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* like a regular file for ext4 to try to delete it. Things
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* will go a bit crazy if that happens, but at least we should
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* try not to panic the whole kernel. */
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if (needed < 2)
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needed = 2;
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/* But we need to bound the transaction so we don't overflow the
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* journal. */
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if (needed > EXT4_MAX_TRANS_DATA)
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needed = EXT4_MAX_TRANS_DATA;
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return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
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}
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/*
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* Truncate transactions can be complex and absolutely huge. So we need to
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* be able to restart the transaction at a conventient checkpoint to make
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* sure we don't overflow the journal.
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*
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* start_transaction gets us a new handle for a truncate transaction,
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* and extend_transaction tries to extend the existing one a bit. If
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* extend fails, we need to propagate the failure up and restart the
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* transaction in the top-level truncate loop. --sct
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*/
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static handle_t *start_transaction(struct inode *inode)
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{
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handle_t *result;
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result = ext4_journal_start(inode, blocks_for_truncate(inode));
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if (!IS_ERR(result))
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return result;
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ext4_std_error(inode->i_sb, PTR_ERR(result));
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return result;
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}
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/*
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* Try to extend this transaction for the purposes of truncation.
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*
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* Returns 0 if we managed to create more room. If we can't create more
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* room, and the transaction must be restarted we return 1.
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*/
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static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
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{
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if (!ext4_handle_valid(handle))
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return 0;
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if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
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return 0;
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if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
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return 0;
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return 1;
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}
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/*
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* Restart the transaction associated with *handle. This does a commit,
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* so before we call here everything must be consistently dirtied against
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* this transaction.
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*/
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static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
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{
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BUG_ON(EXT4_JOURNAL(inode) == NULL);
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jbd_debug(2, "restarting handle %p\n", handle);
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return ext4_journal_restart(handle, blocks_for_truncate(inode));
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}
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/*
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* Called at the last iput() if i_nlink is zero.
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*/
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void ext4_delete_inode(struct inode *inode)
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{
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handle_t *handle;
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int err;
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if (ext4_should_order_data(inode))
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ext4_begin_ordered_truncate(inode, 0);
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truncate_inode_pages(&inode->i_data, 0);
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if (is_bad_inode(inode))
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goto no_delete;
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handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
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if (IS_ERR(handle)) {
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ext4_std_error(inode->i_sb, PTR_ERR(handle));
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/*
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* If we're going to skip the normal cleanup, we still need to
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* make sure that the in-core orphan linked list is properly
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* cleaned up.
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*/
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ext4_orphan_del(NULL, inode);
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goto no_delete;
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}
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if (IS_SYNC(inode))
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ext4_handle_sync(handle);
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inode->i_size = 0;
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err = ext4_mark_inode_dirty(handle, inode);
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if (err) {
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ext4_warning(inode->i_sb, __func__,
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"couldn't mark inode dirty (err %d)", err);
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goto stop_handle;
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}
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if (inode->i_blocks)
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ext4_truncate(inode);
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/*
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* ext4_ext_truncate() doesn't reserve any slop when it
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* restarts journal transactions; therefore there may not be
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* enough credits left in the handle to remove the inode from
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* the orphan list and set the dtime field.
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*/
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if (!ext4_handle_has_enough_credits(handle, 3)) {
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err = ext4_journal_extend(handle, 3);
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if (err > 0)
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err = ext4_journal_restart(handle, 3);
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if (err != 0) {
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ext4_warning(inode->i_sb, __func__,
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"couldn't extend journal (err %d)", err);
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stop_handle:
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ext4_journal_stop(handle);
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goto no_delete;
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}
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}
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/*
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* Kill off the orphan record which ext4_truncate created.
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* AKPM: I think this can be inside the above `if'.
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* Note that ext4_orphan_del() has to be able to cope with the
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* deletion of a non-existent orphan - this is because we don't
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* know if ext4_truncate() actually created an orphan record.
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* (Well, we could do this if we need to, but heck - it works)
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*/
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ext4_orphan_del(handle, inode);
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EXT4_I(inode)->i_dtime = get_seconds();
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/*
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* One subtle ordering requirement: if anything has gone wrong
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* (transaction abort, IO errors, whatever), then we can still
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* do these next steps (the fs will already have been marked as
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* having errors), but we can't free the inode if the mark_dirty
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* fails.
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*/
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if (ext4_mark_inode_dirty(handle, inode))
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/* If that failed, just do the required in-core inode clear. */
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clear_inode(inode);
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else
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ext4_free_inode(handle, inode);
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ext4_journal_stop(handle);
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return;
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no_delete:
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clear_inode(inode); /* We must guarantee clearing of inode... */
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}
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typedef struct {
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__le32 *p;
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__le32 key;
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struct buffer_head *bh;
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} Indirect;
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static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
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{
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p->key = *(p->p = v);
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p->bh = bh;
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}
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/**
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* ext4_block_to_path - parse the block number into array of offsets
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* @inode: inode in question (we are only interested in its superblock)
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* @i_block: block number to be parsed
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* @offsets: array to store the offsets in
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* @boundary: set this non-zero if the referred-to block is likely to be
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* followed (on disk) by an indirect block.
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*
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* To store the locations of file's data ext4 uses a data structure common
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* for UNIX filesystems - tree of pointers anchored in the inode, with
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* data blocks at leaves and indirect blocks in intermediate nodes.
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* This function translates the block number into path in that tree -
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* return value is the path length and @offsets[n] is the offset of
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* pointer to (n+1)th node in the nth one. If @block is out of range
|
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* (negative or too large) warning is printed and zero returned.
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*
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* Note: function doesn't find node addresses, so no IO is needed. All
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* we need to know is the capacity of indirect blocks (taken from the
|
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* inode->i_sb).
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*/
|
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|
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/*
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* Portability note: the last comparison (check that we fit into triple
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* indirect block) is spelled differently, because otherwise on an
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* architecture with 32-bit longs and 8Kb pages we might get into trouble
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* if our filesystem had 8Kb blocks. We might use long long, but that would
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* kill us on x86. Oh, well, at least the sign propagation does not matter -
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* i_block would have to be negative in the very beginning, so we would not
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* get there at all.
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*/
|
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|
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static int ext4_block_to_path(struct inode *inode,
|
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ext4_lblk_t i_block,
|
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ext4_lblk_t offsets[4], int *boundary)
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{
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int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
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int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
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const long direct_blocks = EXT4_NDIR_BLOCKS,
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indirect_blocks = ptrs,
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double_blocks = (1 << (ptrs_bits * 2));
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int n = 0;
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int final = 0;
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|
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if (i_block < 0) {
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ext4_warning(inode->i_sb, "ext4_block_to_path", "block < 0");
|
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} else if (i_block < direct_blocks) {
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offsets[n++] = i_block;
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final = direct_blocks;
|
|
} else if ((i_block -= direct_blocks) < indirect_blocks) {
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offsets[n++] = EXT4_IND_BLOCK;
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offsets[n++] = i_block;
|
|
final = ptrs;
|
|
} else if ((i_block -= indirect_blocks) < double_blocks) {
|
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offsets[n++] = EXT4_DIND_BLOCK;
|
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offsets[n++] = i_block >> ptrs_bits;
|
|
offsets[n++] = i_block & (ptrs - 1);
|
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final = ptrs;
|
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} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
|
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offsets[n++] = EXT4_TIND_BLOCK;
|
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offsets[n++] = i_block >> (ptrs_bits * 2);
|
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offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
|
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offsets[n++] = i_block & (ptrs - 1);
|
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final = ptrs;
|
|
} else {
|
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ext4_warning(inode->i_sb, "ext4_block_to_path",
|
|
"block %lu > max in inode %lu",
|
|
i_block + direct_blocks +
|
|
indirect_blocks + double_blocks, inode->i_ino);
|
|
}
|
|
if (boundary)
|
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*boundary = final - 1 - (i_block & (ptrs - 1));
|
|
return n;
|
|
}
|
|
|
|
static int __ext4_check_blockref(const char *function, struct inode *inode,
|
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__le32 *p, unsigned int max)
|
|
{
|
|
__le32 *bref = p;
|
|
unsigned int blk;
|
|
|
|
while (bref < p+max) {
|
|
blk = le32_to_cpu(*bref++);
|
|
if (blk &&
|
|
unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
|
|
blk, 1))) {
|
|
ext4_error(inode->i_sb, function,
|
|
"invalid block reference %u "
|
|
"in inode #%lu", blk, inode->i_ino);
|
|
return -EIO;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
#define ext4_check_indirect_blockref(inode, bh) \
|
|
__ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data, \
|
|
EXT4_ADDR_PER_BLOCK((inode)->i_sb))
|
|
|
|
#define ext4_check_inode_blockref(inode) \
|
|
__ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data, \
|
|
EXT4_NDIR_BLOCKS)
|
|
|
|
/**
|
|
* ext4_get_branch - read the chain of indirect blocks leading to data
|
|
* @inode: inode in question
|
|
* @depth: depth of the chain (1 - direct pointer, etc.)
|
|
* @offsets: offsets of pointers in inode/indirect blocks
|
|
* @chain: place to store the result
|
|
* @err: here we store the error value
|
|
*
|
|
* Function fills the array of triples <key, p, bh> and returns %NULL
|
|
* if everything went OK or the pointer to the last filled triple
|
|
* (incomplete one) otherwise. Upon the return chain[i].key contains
|
|
* the number of (i+1)-th block in the chain (as it is stored in memory,
|
|
* i.e. little-endian 32-bit), chain[i].p contains the address of that
|
|
* number (it points into struct inode for i==0 and into the bh->b_data
|
|
* for i>0) and chain[i].bh points to the buffer_head of i-th indirect
|
|
* block for i>0 and NULL for i==0. In other words, it holds the block
|
|
* numbers of the chain, addresses they were taken from (and where we can
|
|
* verify that chain did not change) and buffer_heads hosting these
|
|
* numbers.
|
|
*
|
|
* Function stops when it stumbles upon zero pointer (absent block)
|
|
* (pointer to last triple returned, *@err == 0)
|
|
* or when it gets an IO error reading an indirect block
|
|
* (ditto, *@err == -EIO)
|
|
* or when it reads all @depth-1 indirect blocks successfully and finds
|
|
* the whole chain, all way to the data (returns %NULL, *err == 0).
|
|
*
|
|
* Need to be called with
|
|
* down_read(&EXT4_I(inode)->i_data_sem)
|
|
*/
|
|
static Indirect *ext4_get_branch(struct inode *inode, int depth,
|
|
ext4_lblk_t *offsets,
|
|
Indirect chain[4], int *err)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
Indirect *p = chain;
|
|
struct buffer_head *bh;
|
|
|
|
*err = 0;
|
|
/* i_data is not going away, no lock needed */
|
|
add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
|
|
if (!p->key)
|
|
goto no_block;
|
|
while (--depth) {
|
|
bh = sb_getblk(sb, le32_to_cpu(p->key));
|
|
if (unlikely(!bh))
|
|
goto failure;
|
|
|
|
if (!bh_uptodate_or_lock(bh)) {
|
|
if (bh_submit_read(bh) < 0) {
|
|
put_bh(bh);
|
|
goto failure;
|
|
}
|
|
/* validate block references */
|
|
if (ext4_check_indirect_blockref(inode, bh)) {
|
|
put_bh(bh);
|
|
goto failure;
|
|
}
|
|
}
|
|
|
|
add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
|
|
/* Reader: end */
|
|
if (!p->key)
|
|
goto no_block;
|
|
}
|
|
return NULL;
|
|
|
|
failure:
|
|
*err = -EIO;
|
|
no_block:
|
|
return p;
|
|
}
|
|
|
|
/**
|
|
* ext4_find_near - find a place for allocation with sufficient locality
|
|
* @inode: owner
|
|
* @ind: descriptor of indirect block.
|
|
*
|
|
* This function returns the preferred place for block allocation.
|
|
* It is used when heuristic for sequential allocation fails.
|
|
* Rules are:
|
|
* + if there is a block to the left of our position - allocate near it.
|
|
* + if pointer will live in indirect block - allocate near that block.
|
|
* + if pointer will live in inode - allocate in the same
|
|
* cylinder group.
|
|
*
|
|
* In the latter case we colour the starting block by the callers PID to
|
|
* prevent it from clashing with concurrent allocations for a different inode
|
|
* in the same block group. The PID is used here so that functionally related
|
|
* files will be close-by on-disk.
|
|
*
|
|
* Caller must make sure that @ind is valid and will stay that way.
|
|
*/
|
|
static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
|
|
{
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
|
|
__le32 *p;
|
|
ext4_fsblk_t bg_start;
|
|
ext4_fsblk_t last_block;
|
|
ext4_grpblk_t colour;
|
|
ext4_group_t block_group;
|
|
int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
|
|
|
|
/* Try to find previous block */
|
|
for (p = ind->p - 1; p >= start; p--) {
|
|
if (*p)
|
|
return le32_to_cpu(*p);
|
|
}
|
|
|
|
/* No such thing, so let's try location of indirect block */
|
|
if (ind->bh)
|
|
return ind->bh->b_blocknr;
|
|
|
|
/*
|
|
* It is going to be referred to from the inode itself? OK, just put it
|
|
* into the same cylinder group then.
|
|
*/
|
|
block_group = ei->i_block_group;
|
|
if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
|
|
block_group &= ~(flex_size-1);
|
|
if (S_ISREG(inode->i_mode))
|
|
block_group++;
|
|
}
|
|
bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
|
|
last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
|
|
|
|
/*
|
|
* If we are doing delayed allocation, we don't need take
|
|
* colour into account.
|
|
*/
|
|
if (test_opt(inode->i_sb, DELALLOC))
|
|
return bg_start;
|
|
|
|
if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
|
|
colour = (current->pid % 16) *
|
|
(EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
|
|
else
|
|
colour = (current->pid % 16) * ((last_block - bg_start) / 16);
|
|
return bg_start + colour;
|
|
}
|
|
|
|
/**
|
|
* ext4_find_goal - find a preferred place for allocation.
|
|
* @inode: owner
|
|
* @block: block we want
|
|
* @partial: pointer to the last triple within a chain
|
|
*
|
|
* Normally this function find the preferred place for block allocation,
|
|
* returns it.
|
|
*/
|
|
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
|
|
Indirect *partial)
|
|
{
|
|
/*
|
|
* XXX need to get goal block from mballoc's data structures
|
|
*/
|
|
|
|
return ext4_find_near(inode, partial);
|
|
}
|
|
|
|
/**
|
|
* ext4_blks_to_allocate: Look up the block map and count the number
|
|
* of direct blocks need to be allocated for the given branch.
|
|
*
|
|
* @branch: chain of indirect blocks
|
|
* @k: number of blocks need for indirect blocks
|
|
* @blks: number of data blocks to be mapped.
|
|
* @blocks_to_boundary: the offset in the indirect block
|
|
*
|
|
* return the total number of blocks to be allocate, including the
|
|
* direct and indirect blocks.
|
|
*/
|
|
static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
|
|
int blocks_to_boundary)
|
|
{
|
|
unsigned int count = 0;
|
|
|
|
/*
|
|
* Simple case, [t,d]Indirect block(s) has not allocated yet
|
|
* then it's clear blocks on that path have not allocated
|
|
*/
|
|
if (k > 0) {
|
|
/* right now we don't handle cross boundary allocation */
|
|
if (blks < blocks_to_boundary + 1)
|
|
count += blks;
|
|
else
|
|
count += blocks_to_boundary + 1;
|
|
return count;
|
|
}
|
|
|
|
count++;
|
|
while (count < blks && count <= blocks_to_boundary &&
|
|
le32_to_cpu(*(branch[0].p + count)) == 0) {
|
|
count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
/**
|
|
* ext4_alloc_blocks: multiple allocate blocks needed for a branch
|
|
* @indirect_blks: the number of blocks need to allocate for indirect
|
|
* blocks
|
|
*
|
|
* @new_blocks: on return it will store the new block numbers for
|
|
* the indirect blocks(if needed) and the first direct block,
|
|
* @blks: on return it will store the total number of allocated
|
|
* direct blocks
|
|
*/
|
|
static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t iblock, ext4_fsblk_t goal,
|
|
int indirect_blks, int blks,
|
|
ext4_fsblk_t new_blocks[4], int *err)
|
|
{
|
|
struct ext4_allocation_request ar;
|
|
int target, i;
|
|
unsigned long count = 0, blk_allocated = 0;
|
|
int index = 0;
|
|
ext4_fsblk_t current_block = 0;
|
|
int ret = 0;
|
|
|
|
/*
|
|
* Here we try to allocate the requested multiple blocks at once,
|
|
* on a best-effort basis.
|
|
* To build a branch, we should allocate blocks for
|
|
* the indirect blocks(if not allocated yet), and at least
|
|
* the first direct block of this branch. That's the
|
|
* minimum number of blocks need to allocate(required)
|
|
*/
|
|
/* first we try to allocate the indirect blocks */
|
|
target = indirect_blks;
|
|
while (target > 0) {
|
|
count = target;
|
|
/* allocating blocks for indirect blocks and direct blocks */
|
|
current_block = ext4_new_meta_blocks(handle, inode,
|
|
goal, &count, err);
|
|
if (*err)
|
|
goto failed_out;
|
|
|
|
target -= count;
|
|
/* allocate blocks for indirect blocks */
|
|
while (index < indirect_blks && count) {
|
|
new_blocks[index++] = current_block++;
|
|
count--;
|
|
}
|
|
if (count > 0) {
|
|
/*
|
|
* save the new block number
|
|
* for the first direct block
|
|
*/
|
|
new_blocks[index] = current_block;
|
|
printk(KERN_INFO "%s returned more blocks than "
|
|
"requested\n", __func__);
|
|
WARN_ON(1);
|
|
break;
|
|
}
|
|
}
|
|
|
|
target = blks - count ;
|
|
blk_allocated = count;
|
|
if (!target)
|
|
goto allocated;
|
|
/* Now allocate data blocks */
|
|
memset(&ar, 0, sizeof(ar));
|
|
ar.inode = inode;
|
|
ar.goal = goal;
|
|
ar.len = target;
|
|
ar.logical = iblock;
|
|
if (S_ISREG(inode->i_mode))
|
|
/* enable in-core preallocation only for regular files */
|
|
ar.flags = EXT4_MB_HINT_DATA;
|
|
|
|
current_block = ext4_mb_new_blocks(handle, &ar, err);
|
|
|
|
if (*err && (target == blks)) {
|
|
/*
|
|
* if the allocation failed and we didn't allocate
|
|
* any blocks before
|
|
*/
|
|
goto failed_out;
|
|
}
|
|
if (!*err) {
|
|
if (target == blks) {
|
|
/*
|
|
* save the new block number
|
|
* for the first direct block
|
|
*/
|
|
new_blocks[index] = current_block;
|
|
}
|
|
blk_allocated += ar.len;
|
|
}
|
|
allocated:
|
|
/* total number of blocks allocated for direct blocks */
|
|
ret = blk_allocated;
|
|
*err = 0;
|
|
return ret;
|
|
failed_out:
|
|
for (i = 0; i < index; i++)
|
|
ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* ext4_alloc_branch - allocate and set up a chain of blocks.
|
|
* @inode: owner
|
|
* @indirect_blks: number of allocated indirect blocks
|
|
* @blks: number of allocated direct blocks
|
|
* @offsets: offsets (in the blocks) to store the pointers to next.
|
|
* @branch: place to store the chain in.
|
|
*
|
|
* This function allocates blocks, zeroes out all but the last one,
|
|
* links them into chain and (if we are synchronous) writes them to disk.
|
|
* In other words, it prepares a branch that can be spliced onto the
|
|
* inode. It stores the information about that chain in the branch[], in
|
|
* the same format as ext4_get_branch() would do. We are calling it after
|
|
* we had read the existing part of chain and partial points to the last
|
|
* triple of that (one with zero ->key). Upon the exit we have the same
|
|
* picture as after the successful ext4_get_block(), except that in one
|
|
* place chain is disconnected - *branch->p is still zero (we did not
|
|
* set the last link), but branch->key contains the number that should
|
|
* be placed into *branch->p to fill that gap.
|
|
*
|
|
* If allocation fails we free all blocks we've allocated (and forget
|
|
* their buffer_heads) and return the error value the from failed
|
|
* ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
|
|
* as described above and return 0.
|
|
*/
|
|
static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t iblock, int indirect_blks,
|
|
int *blks, ext4_fsblk_t goal,
|
|
ext4_lblk_t *offsets, Indirect *branch)
|
|
{
|
|
int blocksize = inode->i_sb->s_blocksize;
|
|
int i, n = 0;
|
|
int err = 0;
|
|
struct buffer_head *bh;
|
|
int num;
|
|
ext4_fsblk_t new_blocks[4];
|
|
ext4_fsblk_t current_block;
|
|
|
|
num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
|
|
*blks, new_blocks, &err);
|
|
if (err)
|
|
return err;
|
|
|
|
branch[0].key = cpu_to_le32(new_blocks[0]);
|
|
/*
|
|
* metadata blocks and data blocks are allocated.
|
|
*/
|
|
for (n = 1; n <= indirect_blks; n++) {
|
|
/*
|
|
* Get buffer_head for parent block, zero it out
|
|
* and set the pointer to new one, then send
|
|
* parent to disk.
|
|
*/
|
|
bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
|
|
branch[n].bh = bh;
|
|
lock_buffer(bh);
|
|
BUFFER_TRACE(bh, "call get_create_access");
|
|
err = ext4_journal_get_create_access(handle, bh);
|
|
if (err) {
|
|
unlock_buffer(bh);
|
|
brelse(bh);
|
|
goto failed;
|
|
}
|
|
|
|
memset(bh->b_data, 0, blocksize);
|
|
branch[n].p = (__le32 *) bh->b_data + offsets[n];
|
|
branch[n].key = cpu_to_le32(new_blocks[n]);
|
|
*branch[n].p = branch[n].key;
|
|
if (n == indirect_blks) {
|
|
current_block = new_blocks[n];
|
|
/*
|
|
* End of chain, update the last new metablock of
|
|
* the chain to point to the new allocated
|
|
* data blocks numbers
|
|
*/
|
|
for (i=1; i < num; i++)
|
|
*(branch[n].p + i) = cpu_to_le32(++current_block);
|
|
}
|
|
BUFFER_TRACE(bh, "marking uptodate");
|
|
set_buffer_uptodate(bh);
|
|
unlock_buffer(bh);
|
|
|
|
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
|
err = ext4_handle_dirty_metadata(handle, inode, bh);
|
|
if (err)
|
|
goto failed;
|
|
}
|
|
*blks = num;
|
|
return err;
|
|
failed:
|
|
/* Allocation failed, free what we already allocated */
|
|
for (i = 1; i <= n ; i++) {
|
|
BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
|
|
ext4_journal_forget(handle, branch[i].bh);
|
|
}
|
|
for (i = 0; i < indirect_blks; i++)
|
|
ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
|
|
|
|
ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* ext4_splice_branch - splice the allocated branch onto inode.
|
|
* @inode: owner
|
|
* @block: (logical) number of block we are adding
|
|
* @chain: chain of indirect blocks (with a missing link - see
|
|
* ext4_alloc_branch)
|
|
* @where: location of missing link
|
|
* @num: number of indirect blocks we are adding
|
|
* @blks: number of direct blocks we are adding
|
|
*
|
|
* This function fills the missing link and does all housekeeping needed in
|
|
* inode (->i_blocks, etc.). In case of success we end up with the full
|
|
* chain to new block and return 0.
|
|
*/
|
|
static int ext4_splice_branch(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t block, Indirect *where, int num, int blks)
|
|
{
|
|
int i;
|
|
int err = 0;
|
|
ext4_fsblk_t current_block;
|
|
|
|
/*
|
|
* If we're splicing into a [td]indirect block (as opposed to the
|
|
* inode) then we need to get write access to the [td]indirect block
|
|
* before the splice.
|
|
*/
|
|
if (where->bh) {
|
|
BUFFER_TRACE(where->bh, "get_write_access");
|
|
err = ext4_journal_get_write_access(handle, where->bh);
|
|
if (err)
|
|
goto err_out;
|
|
}
|
|
/* That's it */
|
|
|
|
*where->p = where->key;
|
|
|
|
/*
|
|
* Update the host buffer_head or inode to point to more just allocated
|
|
* direct blocks blocks
|
|
*/
|
|
if (num == 0 && blks > 1) {
|
|
current_block = le32_to_cpu(where->key) + 1;
|
|
for (i = 1; i < blks; i++)
|
|
*(where->p + i) = cpu_to_le32(current_block++);
|
|
}
|
|
|
|
/* We are done with atomic stuff, now do the rest of housekeeping */
|
|
|
|
inode->i_ctime = ext4_current_time(inode);
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
|
|
/* had we spliced it onto indirect block? */
|
|
if (where->bh) {
|
|
/*
|
|
* If we spliced it onto an indirect block, we haven't
|
|
* altered the inode. Note however that if it is being spliced
|
|
* onto an indirect block at the very end of the file (the
|
|
* file is growing) then we *will* alter the inode to reflect
|
|
* the new i_size. But that is not done here - it is done in
|
|
* generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
|
|
*/
|
|
jbd_debug(5, "splicing indirect only\n");
|
|
BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
|
|
err = ext4_handle_dirty_metadata(handle, inode, where->bh);
|
|
if (err)
|
|
goto err_out;
|
|
} else {
|
|
/*
|
|
* OK, we spliced it into the inode itself on a direct block.
|
|
* Inode was dirtied above.
|
|
*/
|
|
jbd_debug(5, "splicing direct\n");
|
|
}
|
|
return err;
|
|
|
|
err_out:
|
|
for (i = 1; i <= num; i++) {
|
|
BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
|
|
ext4_journal_forget(handle, where[i].bh);
|
|
ext4_free_blocks(handle, inode,
|
|
le32_to_cpu(where[i-1].key), 1, 0);
|
|
}
|
|
ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* The ext4_ind_get_blocks() function handles non-extents inodes
|
|
* (i.e., using the traditional indirect/double-indirect i_blocks
|
|
* scheme) for ext4_get_blocks().
|
|
*
|
|
* Allocation strategy is simple: if we have to allocate something, we will
|
|
* have to go the whole way to leaf. So let's do it before attaching anything
|
|
* to tree, set linkage between the newborn blocks, write them if sync is
|
|
* required, recheck the path, free and repeat if check fails, otherwise
|
|
* set the last missing link (that will protect us from any truncate-generated
|
|
* removals - all blocks on the path are immune now) and possibly force the
|
|
* write on the parent block.
|
|
* That has a nice additional property: no special recovery from the failed
|
|
* allocations is needed - we simply release blocks and do not touch anything
|
|
* reachable from inode.
|
|
*
|
|
* `handle' can be NULL if create == 0.
|
|
*
|
|
* return > 0, # of blocks mapped or allocated.
|
|
* return = 0, if plain lookup failed.
|
|
* return < 0, error case.
|
|
*
|
|
* The ext4_ind_get_blocks() function should be called with
|
|
* down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
|
|
* blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
|
|
* down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
|
|
* blocks.
|
|
*/
|
|
static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t iblock, unsigned int maxblocks,
|
|
struct buffer_head *bh_result,
|
|
int flags)
|
|
{
|
|
int err = -EIO;
|
|
ext4_lblk_t offsets[4];
|
|
Indirect chain[4];
|
|
Indirect *partial;
|
|
ext4_fsblk_t goal;
|
|
int indirect_blks;
|
|
int blocks_to_boundary = 0;
|
|
int depth;
|
|
int count = 0;
|
|
ext4_fsblk_t first_block = 0;
|
|
|
|
J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
|
|
J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
|
|
depth = ext4_block_to_path(inode, iblock, offsets,
|
|
&blocks_to_boundary);
|
|
|
|
if (depth == 0)
|
|
goto out;
|
|
|
|
partial = ext4_get_branch(inode, depth, offsets, chain, &err);
|
|
|
|
/* Simplest case - block found, no allocation needed */
|
|
if (!partial) {
|
|
first_block = le32_to_cpu(chain[depth - 1].key);
|
|
clear_buffer_new(bh_result);
|
|
count++;
|
|
/*map more blocks*/
|
|
while (count < maxblocks && count <= blocks_to_boundary) {
|
|
ext4_fsblk_t blk;
|
|
|
|
blk = le32_to_cpu(*(chain[depth-1].p + count));
|
|
|
|
if (blk == first_block + count)
|
|
count++;
|
|
else
|
|
break;
|
|
}
|
|
goto got_it;
|
|
}
|
|
|
|
/* Next simple case - plain lookup or failed read of indirect block */
|
|
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
|
|
goto cleanup;
|
|
|
|
/*
|
|
* Okay, we need to do block allocation.
|
|
*/
|
|
goal = ext4_find_goal(inode, iblock, partial);
|
|
|
|
/* the number of blocks need to allocate for [d,t]indirect blocks */
|
|
indirect_blks = (chain + depth) - partial - 1;
|
|
|
|
/*
|
|
* Next look up the indirect map to count the totoal number of
|
|
* direct blocks to allocate for this branch.
|
|
*/
|
|
count = ext4_blks_to_allocate(partial, indirect_blks,
|
|
maxblocks, blocks_to_boundary);
|
|
/*
|
|
* Block out ext4_truncate while we alter the tree
|
|
*/
|
|
err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
|
|
&count, goal,
|
|
offsets + (partial - chain), partial);
|
|
|
|
/*
|
|
* The ext4_splice_branch call will free and forget any buffers
|
|
* on the new chain if there is a failure, but that risks using
|
|
* up transaction credits, especially for bitmaps where the
|
|
* credits cannot be returned. Can we handle this somehow? We
|
|
* may need to return -EAGAIN upwards in the worst case. --sct
|
|
*/
|
|
if (!err)
|
|
err = ext4_splice_branch(handle, inode, iblock,
|
|
partial, indirect_blks, count);
|
|
else
|
|
goto cleanup;
|
|
|
|
set_buffer_new(bh_result);
|
|
got_it:
|
|
map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
|
|
if (count > blocks_to_boundary)
|
|
set_buffer_boundary(bh_result);
|
|
err = count;
|
|
/* Clean up and exit */
|
|
partial = chain + depth - 1; /* the whole chain */
|
|
cleanup:
|
|
while (partial > chain) {
|
|
BUFFER_TRACE(partial->bh, "call brelse");
|
|
brelse(partial->bh);
|
|
partial--;
|
|
}
|
|
BUFFER_TRACE(bh_result, "returned");
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
qsize_t ext4_get_reserved_space(struct inode *inode)
|
|
{
|
|
unsigned long long total;
|
|
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
total = EXT4_I(inode)->i_reserved_data_blocks +
|
|
EXT4_I(inode)->i_reserved_meta_blocks;
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
|
|
return total;
|
|
}
|
|
/*
|
|
* Calculate the number of metadata blocks need to reserve
|
|
* to allocate @blocks for non extent file based file
|
|
*/
|
|
static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
|
|
{
|
|
int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
int ind_blks, dind_blks, tind_blks;
|
|
|
|
/* number of new indirect blocks needed */
|
|
ind_blks = (blocks + icap - 1) / icap;
|
|
|
|
dind_blks = (ind_blks + icap - 1) / icap;
|
|
|
|
tind_blks = 1;
|
|
|
|
return ind_blks + dind_blks + tind_blks;
|
|
}
|
|
|
|
/*
|
|
* Calculate the number of metadata blocks need to reserve
|
|
* to allocate given number of blocks
|
|
*/
|
|
static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
|
|
{
|
|
if (!blocks)
|
|
return 0;
|
|
|
|
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
|
|
return ext4_ext_calc_metadata_amount(inode, blocks);
|
|
|
|
return ext4_indirect_calc_metadata_amount(inode, blocks);
|
|
}
|
|
|
|
static void ext4_da_update_reserve_space(struct inode *inode, int used)
|
|
{
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
int total, mdb, mdb_free;
|
|
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
/* recalculate the number of metablocks still need to be reserved */
|
|
total = EXT4_I(inode)->i_reserved_data_blocks - used;
|
|
mdb = ext4_calc_metadata_amount(inode, total);
|
|
|
|
/* figure out how many metablocks to release */
|
|
BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
|
|
mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
|
|
|
|
if (mdb_free) {
|
|
/* Account for allocated meta_blocks */
|
|
mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
|
|
|
|
/* update fs dirty blocks counter */
|
|
percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
|
|
EXT4_I(inode)->i_allocated_meta_blocks = 0;
|
|
EXT4_I(inode)->i_reserved_meta_blocks = mdb;
|
|
}
|
|
|
|
/* update per-inode reservations */
|
|
BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks);
|
|
EXT4_I(inode)->i_reserved_data_blocks -= used;
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
|
|
/*
|
|
* free those over-booking quota for metadata blocks
|
|
*/
|
|
if (mdb_free)
|
|
vfs_dq_release_reservation_block(inode, mdb_free);
|
|
|
|
/*
|
|
* If we have done all the pending block allocations and if
|
|
* there aren't any writers on the inode, we can discard the
|
|
* inode's preallocations.
|
|
*/
|
|
if (!total && (atomic_read(&inode->i_writecount) == 0))
|
|
ext4_discard_preallocations(inode);
|
|
}
|
|
|
|
static int check_block_validity(struct inode *inode, sector_t logical,
|
|
sector_t phys, int len)
|
|
{
|
|
if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), phys, len)) {
|
|
ext4_error(inode->i_sb, "check_block_validity",
|
|
"inode #%lu logical block %llu mapped to %llu "
|
|
"(size %d)", inode->i_ino,
|
|
(unsigned long long) logical,
|
|
(unsigned long long) phys, len);
|
|
WARN_ON(1);
|
|
return -EIO;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* The ext4_get_blocks() function tries to look up the requested blocks,
|
|
* and returns if the blocks are already mapped.
|
|
*
|
|
* Otherwise it takes the write lock of the i_data_sem and allocate blocks
|
|
* and store the allocated blocks in the result buffer head and mark it
|
|
* mapped.
|
|
*
|
|
* If file type is extents based, it will call ext4_ext_get_blocks(),
|
|
* Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
|
|
* based files
|
|
*
|
|
* On success, it returns the number of blocks being mapped or allocate.
|
|
* if create==0 and the blocks are pre-allocated and uninitialized block,
|
|
* the result buffer head is unmapped. If the create ==1, it will make sure
|
|
* the buffer head is mapped.
|
|
*
|
|
* It returns 0 if plain look up failed (blocks have not been allocated), in
|
|
* that casem, buffer head is unmapped
|
|
*
|
|
* It returns the error in case of allocation failure.
|
|
*/
|
|
int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
|
|
unsigned int max_blocks, struct buffer_head *bh,
|
|
int flags)
|
|
{
|
|
int retval;
|
|
|
|
clear_buffer_mapped(bh);
|
|
clear_buffer_unwritten(bh);
|
|
|
|
/*
|
|
* Try to see if we can get the block without requesting a new
|
|
* file system block.
|
|
*/
|
|
down_read((&EXT4_I(inode)->i_data_sem));
|
|
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
|
|
retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
|
|
bh, 0);
|
|
} else {
|
|
retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
|
|
bh, 0);
|
|
}
|
|
up_read((&EXT4_I(inode)->i_data_sem));
|
|
|
|
if (retval > 0 && buffer_mapped(bh)) {
|
|
int ret = check_block_validity(inode, block,
|
|
bh->b_blocknr, retval);
|
|
if (ret != 0)
|
|
return ret;
|
|
}
|
|
|
|
/* If it is only a block(s) look up */
|
|
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
|
|
return retval;
|
|
|
|
/*
|
|
* Returns if the blocks have already allocated
|
|
*
|
|
* Note that if blocks have been preallocated
|
|
* ext4_ext_get_block() returns th create = 0
|
|
* with buffer head unmapped.
|
|
*/
|
|
if (retval > 0 && buffer_mapped(bh))
|
|
return retval;
|
|
|
|
/*
|
|
* When we call get_blocks without the create flag, the
|
|
* BH_Unwritten flag could have gotten set if the blocks
|
|
* requested were part of a uninitialized extent. We need to
|
|
* clear this flag now that we are committed to convert all or
|
|
* part of the uninitialized extent to be an initialized
|
|
* extent. This is because we need to avoid the combination
|
|
* of BH_Unwritten and BH_Mapped flags being simultaneously
|
|
* set on the buffer_head.
|
|
*/
|
|
clear_buffer_unwritten(bh);
|
|
|
|
/*
|
|
* New blocks allocate and/or writing to uninitialized extent
|
|
* will possibly result in updating i_data, so we take
|
|
* the write lock of i_data_sem, and call get_blocks()
|
|
* with create == 1 flag.
|
|
*/
|
|
down_write((&EXT4_I(inode)->i_data_sem));
|
|
|
|
/*
|
|
* if the caller is from delayed allocation writeout path
|
|
* we have already reserved fs blocks for allocation
|
|
* let the underlying get_block() function know to
|
|
* avoid double accounting
|
|
*/
|
|
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
|
|
EXT4_I(inode)->i_delalloc_reserved_flag = 1;
|
|
/*
|
|
* We need to check for EXT4 here because migrate
|
|
* could have changed the inode type in between
|
|
*/
|
|
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
|
|
retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
|
|
bh, flags);
|
|
} else {
|
|
retval = ext4_ind_get_blocks(handle, inode, block,
|
|
max_blocks, bh, flags);
|
|
|
|
if (retval > 0 && buffer_new(bh)) {
|
|
/*
|
|
* We allocated new blocks which will result in
|
|
* i_data's format changing. Force the migrate
|
|
* to fail by clearing migrate flags
|
|
*/
|
|
EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
|
|
~EXT4_EXT_MIGRATE;
|
|
}
|
|
}
|
|
|
|
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
|
|
EXT4_I(inode)->i_delalloc_reserved_flag = 0;
|
|
|
|
/*
|
|
* Update reserved blocks/metadata blocks after successful
|
|
* block allocation which had been deferred till now.
|
|
*/
|
|
if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
|
|
ext4_da_update_reserve_space(inode, retval);
|
|
|
|
up_write((&EXT4_I(inode)->i_data_sem));
|
|
if (retval > 0 && buffer_mapped(bh)) {
|
|
int ret = check_block_validity(inode, block,
|
|
bh->b_blocknr, retval);
|
|
if (ret != 0)
|
|
return ret;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
/* Maximum number of blocks we map for direct IO at once. */
|
|
#define DIO_MAX_BLOCKS 4096
|
|
|
|
int ext4_get_block(struct inode *inode, sector_t iblock,
|
|
struct buffer_head *bh_result, int create)
|
|
{
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
int ret = 0, started = 0;
|
|
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
|
|
int dio_credits;
|
|
|
|
if (create && !handle) {
|
|
/* Direct IO write... */
|
|
if (max_blocks > DIO_MAX_BLOCKS)
|
|
max_blocks = DIO_MAX_BLOCKS;
|
|
dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
|
|
handle = ext4_journal_start(inode, dio_credits);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
started = 1;
|
|
}
|
|
|
|
ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
|
|
create ? EXT4_GET_BLOCKS_CREATE : 0);
|
|
if (ret > 0) {
|
|
bh_result->b_size = (ret << inode->i_blkbits);
|
|
ret = 0;
|
|
}
|
|
if (started)
|
|
ext4_journal_stop(handle);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* `handle' can be NULL if create is zero
|
|
*/
|
|
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t block, int create, int *errp)
|
|
{
|
|
struct buffer_head dummy;
|
|
int fatal = 0, err;
|
|
int flags = 0;
|
|
|
|
J_ASSERT(handle != NULL || create == 0);
|
|
|
|
dummy.b_state = 0;
|
|
dummy.b_blocknr = -1000;
|
|
buffer_trace_init(&dummy.b_history);
|
|
if (create)
|
|
flags |= EXT4_GET_BLOCKS_CREATE;
|
|
err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
|
|
/*
|
|
* ext4_get_blocks() returns number of blocks mapped. 0 in
|
|
* case of a HOLE.
|
|
*/
|
|
if (err > 0) {
|
|
if (err > 1)
|
|
WARN_ON(1);
|
|
err = 0;
|
|
}
|
|
*errp = err;
|
|
if (!err && buffer_mapped(&dummy)) {
|
|
struct buffer_head *bh;
|
|
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
|
|
if (!bh) {
|
|
*errp = -EIO;
|
|
goto err;
|
|
}
|
|
if (buffer_new(&dummy)) {
|
|
J_ASSERT(create != 0);
|
|
J_ASSERT(handle != NULL);
|
|
|
|
/*
|
|
* Now that we do not always journal data, we should
|
|
* keep in mind whether this should always journal the
|
|
* new buffer as metadata. For now, regular file
|
|
* writes use ext4_get_block instead, so it's not a
|
|
* problem.
|
|
*/
|
|
lock_buffer(bh);
|
|
BUFFER_TRACE(bh, "call get_create_access");
|
|
fatal = ext4_journal_get_create_access(handle, bh);
|
|
if (!fatal && !buffer_uptodate(bh)) {
|
|
memset(bh->b_data, 0, inode->i_sb->s_blocksize);
|
|
set_buffer_uptodate(bh);
|
|
}
|
|
unlock_buffer(bh);
|
|
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
|
err = ext4_handle_dirty_metadata(handle, inode, bh);
|
|
if (!fatal)
|
|
fatal = err;
|
|
} else {
|
|
BUFFER_TRACE(bh, "not a new buffer");
|
|
}
|
|
if (fatal) {
|
|
*errp = fatal;
|
|
brelse(bh);
|
|
bh = NULL;
|
|
}
|
|
return bh;
|
|
}
|
|
err:
|
|
return NULL;
|
|
}
|
|
|
|
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t block, int create, int *err)
|
|
{
|
|
struct buffer_head *bh;
|
|
|
|
bh = ext4_getblk(handle, inode, block, create, err);
|
|
if (!bh)
|
|
return bh;
|
|
if (buffer_uptodate(bh))
|
|
return bh;
|
|
ll_rw_block(READ_META, 1, &bh);
|
|
wait_on_buffer(bh);
|
|
if (buffer_uptodate(bh))
|
|
return bh;
|
|
put_bh(bh);
|
|
*err = -EIO;
|
|
return NULL;
|
|
}
|
|
|
|
static int walk_page_buffers(handle_t *handle,
|
|
struct buffer_head *head,
|
|
unsigned from,
|
|
unsigned to,
|
|
int *partial,
|
|
int (*fn)(handle_t *handle,
|
|
struct buffer_head *bh))
|
|
{
|
|
struct buffer_head *bh;
|
|
unsigned block_start, block_end;
|
|
unsigned blocksize = head->b_size;
|
|
int err, ret = 0;
|
|
struct buffer_head *next;
|
|
|
|
for (bh = head, block_start = 0;
|
|
ret == 0 && (bh != head || !block_start);
|
|
block_start = block_end, bh = next)
|
|
{
|
|
next = bh->b_this_page;
|
|
block_end = block_start + blocksize;
|
|
if (block_end <= from || block_start >= to) {
|
|
if (partial && !buffer_uptodate(bh))
|
|
*partial = 1;
|
|
continue;
|
|
}
|
|
err = (*fn)(handle, bh);
|
|
if (!ret)
|
|
ret = err;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* To preserve ordering, it is essential that the hole instantiation and
|
|
* the data write be encapsulated in a single transaction. We cannot
|
|
* close off a transaction and start a new one between the ext4_get_block()
|
|
* and the commit_write(). So doing the jbd2_journal_start at the start of
|
|
* prepare_write() is the right place.
|
|
*
|
|
* Also, this function can nest inside ext4_writepage() ->
|
|
* block_write_full_page(). In that case, we *know* that ext4_writepage()
|
|
* has generated enough buffer credits to do the whole page. So we won't
|
|
* block on the journal in that case, which is good, because the caller may
|
|
* be PF_MEMALLOC.
|
|
*
|
|
* By accident, ext4 can be reentered when a transaction is open via
|
|
* quota file writes. If we were to commit the transaction while thus
|
|
* reentered, there can be a deadlock - we would be holding a quota
|
|
* lock, and the commit would never complete if another thread had a
|
|
* transaction open and was blocking on the quota lock - a ranking
|
|
* violation.
|
|
*
|
|
* So what we do is to rely on the fact that jbd2_journal_stop/journal_start
|
|
* will _not_ run commit under these circumstances because handle->h_ref
|
|
* is elevated. We'll still have enough credits for the tiny quotafile
|
|
* write.
|
|
*/
|
|
static int do_journal_get_write_access(handle_t *handle,
|
|
struct buffer_head *bh)
|
|
{
|
|
if (!buffer_mapped(bh) || buffer_freed(bh))
|
|
return 0;
|
|
return ext4_journal_get_write_access(handle, bh);
|
|
}
|
|
|
|
static int ext4_write_begin(struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned flags,
|
|
struct page **pagep, void **fsdata)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
int ret, needed_blocks;
|
|
handle_t *handle;
|
|
int retries = 0;
|
|
struct page *page;
|
|
pgoff_t index;
|
|
unsigned from, to;
|
|
|
|
trace_mark(ext4_write_begin,
|
|
"dev %s ino %lu pos %llu len %u flags %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, flags);
|
|
/*
|
|
* Reserve one block more for addition to orphan list in case
|
|
* we allocate blocks but write fails for some reason
|
|
*/
|
|
needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
|
|
index = pos >> PAGE_CACHE_SHIFT;
|
|
from = pos & (PAGE_CACHE_SIZE - 1);
|
|
to = from + len;
|
|
|
|
retry:
|
|
handle = ext4_journal_start(inode, needed_blocks);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
|
|
/* We cannot recurse into the filesystem as the transaction is already
|
|
* started */
|
|
flags |= AOP_FLAG_NOFS;
|
|
|
|
page = grab_cache_page_write_begin(mapping, index, flags);
|
|
if (!page) {
|
|
ext4_journal_stop(handle);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
*pagep = page;
|
|
|
|
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
|
|
ext4_get_block);
|
|
|
|
if (!ret && ext4_should_journal_data(inode)) {
|
|
ret = walk_page_buffers(handle, page_buffers(page),
|
|
from, to, NULL, do_journal_get_write_access);
|
|
}
|
|
|
|
if (ret) {
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
/*
|
|
* block_write_begin may have instantiated a few blocks
|
|
* outside i_size. Trim these off again. Don't need
|
|
* i_size_read because we hold i_mutex.
|
|
*
|
|
* Add inode to orphan list in case we crash before
|
|
* truncate finishes
|
|
*/
|
|
if (pos + len > inode->i_size)
|
|
ext4_orphan_add(handle, inode);
|
|
|
|
ext4_journal_stop(handle);
|
|
if (pos + len > inode->i_size) {
|
|
vmtruncate(inode, inode->i_size);
|
|
/*
|
|
* If vmtruncate failed early the inode might
|
|
* still be on the orphan list; we need to
|
|
* make sure the inode is removed from the
|
|
* orphan list in that case.
|
|
*/
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(NULL, inode);
|
|
}
|
|
}
|
|
|
|
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
|
|
goto retry;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* For write_end() in data=journal mode */
|
|
static int write_end_fn(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
if (!buffer_mapped(bh) || buffer_freed(bh))
|
|
return 0;
|
|
set_buffer_uptodate(bh);
|
|
return ext4_handle_dirty_metadata(handle, NULL, bh);
|
|
}
|
|
|
|
static int ext4_generic_write_end(struct file *file,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
int i_size_changed = 0;
|
|
struct inode *inode = mapping->host;
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
|
|
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
|
|
|
|
/*
|
|
* No need to use i_size_read() here, the i_size
|
|
* cannot change under us because we hold i_mutex.
|
|
*
|
|
* But it's important to update i_size while still holding page lock:
|
|
* page writeout could otherwise come in and zero beyond i_size.
|
|
*/
|
|
if (pos + copied > inode->i_size) {
|
|
i_size_write(inode, pos + copied);
|
|
i_size_changed = 1;
|
|
}
|
|
|
|
if (pos + copied > EXT4_I(inode)->i_disksize) {
|
|
/* We need to mark inode dirty even if
|
|
* new_i_size is less that inode->i_size
|
|
* bu greater than i_disksize.(hint delalloc)
|
|
*/
|
|
ext4_update_i_disksize(inode, (pos + copied));
|
|
i_size_changed = 1;
|
|
}
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
|
|
/*
|
|
* Don't mark the inode dirty under page lock. First, it unnecessarily
|
|
* makes the holding time of page lock longer. Second, it forces lock
|
|
* ordering of page lock and transaction start for journaling
|
|
* filesystems.
|
|
*/
|
|
if (i_size_changed)
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
|
|
return copied;
|
|
}
|
|
|
|
/*
|
|
* We need to pick up the new inode size which generic_commit_write gave us
|
|
* `file' can be NULL - eg, when called from page_symlink().
|
|
*
|
|
* ext4 never places buffers on inode->i_mapping->private_list. metadata
|
|
* buffers are managed internally.
|
|
*/
|
|
static int ext4_ordered_write_end(struct file *file,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
struct inode *inode = mapping->host;
|
|
int ret = 0, ret2;
|
|
|
|
trace_mark(ext4_ordered_write_end,
|
|
"dev %s ino %lu pos %llu len %u copied %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, copied);
|
|
ret = ext4_jbd2_file_inode(handle, inode);
|
|
|
|
if (ret == 0) {
|
|
ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
|
|
page, fsdata);
|
|
copied = ret2;
|
|
if (pos + len > inode->i_size)
|
|
/* if we have allocated more blocks and copied
|
|
* less. We will have blocks allocated outside
|
|
* inode->i_size. So truncate them
|
|
*/
|
|
ext4_orphan_add(handle, inode);
|
|
if (ret2 < 0)
|
|
ret = ret2;
|
|
}
|
|
ret2 = ext4_journal_stop(handle);
|
|
if (!ret)
|
|
ret = ret2;
|
|
|
|
if (pos + len > inode->i_size) {
|
|
vmtruncate(inode, inode->i_size);
|
|
/*
|
|
* If vmtruncate failed early the inode might still be
|
|
* on the orphan list; we need to make sure the inode
|
|
* is removed from the orphan list in that case.
|
|
*/
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(NULL, inode);
|
|
}
|
|
|
|
|
|
return ret ? ret : copied;
|
|
}
|
|
|
|
static int ext4_writeback_write_end(struct file *file,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
struct inode *inode = mapping->host;
|
|
int ret = 0, ret2;
|
|
|
|
trace_mark(ext4_writeback_write_end,
|
|
"dev %s ino %lu pos %llu len %u copied %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, copied);
|
|
ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
|
|
page, fsdata);
|
|
copied = ret2;
|
|
if (pos + len > inode->i_size)
|
|
/* if we have allocated more blocks and copied
|
|
* less. We will have blocks allocated outside
|
|
* inode->i_size. So truncate them
|
|
*/
|
|
ext4_orphan_add(handle, inode);
|
|
|
|
if (ret2 < 0)
|
|
ret = ret2;
|
|
|
|
ret2 = ext4_journal_stop(handle);
|
|
if (!ret)
|
|
ret = ret2;
|
|
|
|
if (pos + len > inode->i_size) {
|
|
vmtruncate(inode, inode->i_size);
|
|
/*
|
|
* If vmtruncate failed early the inode might still be
|
|
* on the orphan list; we need to make sure the inode
|
|
* is removed from the orphan list in that case.
|
|
*/
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(NULL, inode);
|
|
}
|
|
|
|
return ret ? ret : copied;
|
|
}
|
|
|
|
static int ext4_journalled_write_end(struct file *file,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
struct inode *inode = mapping->host;
|
|
int ret = 0, ret2;
|
|
int partial = 0;
|
|
unsigned from, to;
|
|
loff_t new_i_size;
|
|
|
|
trace_mark(ext4_journalled_write_end,
|
|
"dev %s ino %lu pos %llu len %u copied %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, copied);
|
|
from = pos & (PAGE_CACHE_SIZE - 1);
|
|
to = from + len;
|
|
|
|
if (copied < len) {
|
|
if (!PageUptodate(page))
|
|
copied = 0;
|
|
page_zero_new_buffers(page, from+copied, to);
|
|
}
|
|
|
|
ret = walk_page_buffers(handle, page_buffers(page), from,
|
|
to, &partial, write_end_fn);
|
|
if (!partial)
|
|
SetPageUptodate(page);
|
|
new_i_size = pos + copied;
|
|
if (new_i_size > inode->i_size)
|
|
i_size_write(inode, pos+copied);
|
|
EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
|
|
if (new_i_size > EXT4_I(inode)->i_disksize) {
|
|
ext4_update_i_disksize(inode, new_i_size);
|
|
ret2 = ext4_mark_inode_dirty(handle, inode);
|
|
if (!ret)
|
|
ret = ret2;
|
|
}
|
|
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
if (pos + len > inode->i_size)
|
|
/* if we have allocated more blocks and copied
|
|
* less. We will have blocks allocated outside
|
|
* inode->i_size. So truncate them
|
|
*/
|
|
ext4_orphan_add(handle, inode);
|
|
|
|
ret2 = ext4_journal_stop(handle);
|
|
if (!ret)
|
|
ret = ret2;
|
|
if (pos + len > inode->i_size) {
|
|
vmtruncate(inode, inode->i_size);
|
|
/*
|
|
* If vmtruncate failed early the inode might still be
|
|
* on the orphan list; we need to make sure the inode
|
|
* is removed from the orphan list in that case.
|
|
*/
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(NULL, inode);
|
|
}
|
|
|
|
return ret ? ret : copied;
|
|
}
|
|
|
|
static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
|
|
{
|
|
int retries = 0;
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
unsigned long md_needed, mdblocks, total = 0;
|
|
|
|
/*
|
|
* recalculate the amount of metadata blocks to reserve
|
|
* in order to allocate nrblocks
|
|
* worse case is one extent per block
|
|
*/
|
|
repeat:
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
|
|
mdblocks = ext4_calc_metadata_amount(inode, total);
|
|
BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
|
|
|
|
md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
|
|
total = md_needed + nrblocks;
|
|
|
|
/*
|
|
* Make quota reservation here to prevent quota overflow
|
|
* later. Real quota accounting is done at pages writeout
|
|
* time.
|
|
*/
|
|
if (vfs_dq_reserve_block(inode, total)) {
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
return -EDQUOT;
|
|
}
|
|
|
|
if (ext4_claim_free_blocks(sbi, total)) {
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
|
|
yield();
|
|
goto repeat;
|
|
}
|
|
vfs_dq_release_reservation_block(inode, total);
|
|
return -ENOSPC;
|
|
}
|
|
EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
|
|
EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
|
|
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
return 0; /* success */
|
|
}
|
|
|
|
static void ext4_da_release_space(struct inode *inode, int to_free)
|
|
{
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
int total, mdb, mdb_free, release;
|
|
|
|
if (!to_free)
|
|
return; /* Nothing to release, exit */
|
|
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
|
|
if (!EXT4_I(inode)->i_reserved_data_blocks) {
|
|
/*
|
|
* if there is no reserved blocks, but we try to free some
|
|
* then the counter is messed up somewhere.
|
|
* but since this function is called from invalidate
|
|
* page, it's harmless to return without any action
|
|
*/
|
|
printk(KERN_INFO "ext4 delalloc try to release %d reserved "
|
|
"blocks for inode %lu, but there is no reserved "
|
|
"data blocks\n", to_free, inode->i_ino);
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
return;
|
|
}
|
|
|
|
/* recalculate the number of metablocks still need to be reserved */
|
|
total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
|
|
mdb = ext4_calc_metadata_amount(inode, total);
|
|
|
|
/* figure out how many metablocks to release */
|
|
BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
|
|
mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
|
|
|
|
release = to_free + mdb_free;
|
|
|
|
/* update fs dirty blocks counter for truncate case */
|
|
percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
|
|
|
|
/* update per-inode reservations */
|
|
BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
|
|
EXT4_I(inode)->i_reserved_data_blocks -= to_free;
|
|
|
|
BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
|
|
EXT4_I(inode)->i_reserved_meta_blocks = mdb;
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
|
|
vfs_dq_release_reservation_block(inode, release);
|
|
}
|
|
|
|
static void ext4_da_page_release_reservation(struct page *page,
|
|
unsigned long offset)
|
|
{
|
|
int to_release = 0;
|
|
struct buffer_head *head, *bh;
|
|
unsigned int curr_off = 0;
|
|
|
|
head = page_buffers(page);
|
|
bh = head;
|
|
do {
|
|
unsigned int next_off = curr_off + bh->b_size;
|
|
|
|
if ((offset <= curr_off) && (buffer_delay(bh))) {
|
|
to_release++;
|
|
clear_buffer_delay(bh);
|
|
}
|
|
curr_off = next_off;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
ext4_da_release_space(page->mapping->host, to_release);
|
|
}
|
|
|
|
/*
|
|
* Delayed allocation stuff
|
|
*/
|
|
|
|
struct mpage_da_data {
|
|
struct inode *inode;
|
|
sector_t b_blocknr; /* start block number of extent */
|
|
size_t b_size; /* size of extent */
|
|
unsigned long b_state; /* state of the extent */
|
|
unsigned long first_page, next_page; /* extent of pages */
|
|
struct writeback_control *wbc;
|
|
int io_done;
|
|
int pages_written;
|
|
int retval;
|
|
};
|
|
|
|
/*
|
|
* mpage_da_submit_io - walks through extent of pages and try to write
|
|
* them with writepage() call back
|
|
*
|
|
* @mpd->inode: inode
|
|
* @mpd->first_page: first page of the extent
|
|
* @mpd->next_page: page after the last page of the extent
|
|
*
|
|
* By the time mpage_da_submit_io() is called we expect all blocks
|
|
* to be allocated. this may be wrong if allocation failed.
|
|
*
|
|
* As pages are already locked by write_cache_pages(), we can't use it
|
|
*/
|
|
static int mpage_da_submit_io(struct mpage_da_data *mpd)
|
|
{
|
|
long pages_skipped;
|
|
struct pagevec pvec;
|
|
unsigned long index, end;
|
|
int ret = 0, err, nr_pages, i;
|
|
struct inode *inode = mpd->inode;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
|
|
BUG_ON(mpd->next_page <= mpd->first_page);
|
|
/*
|
|
* We need to start from the first_page to the next_page - 1
|
|
* to make sure we also write the mapped dirty buffer_heads.
|
|
* If we look at mpd->b_blocknr we would only be looking
|
|
* at the currently mapped buffer_heads.
|
|
*/
|
|
index = mpd->first_page;
|
|
end = mpd->next_page - 1;
|
|
|
|
pagevec_init(&pvec, 0);
|
|
while (index <= end) {
|
|
nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
|
|
if (nr_pages == 0)
|
|
break;
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page = pvec.pages[i];
|
|
|
|
index = page->index;
|
|
if (index > end)
|
|
break;
|
|
index++;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
BUG_ON(PageWriteback(page));
|
|
|
|
pages_skipped = mpd->wbc->pages_skipped;
|
|
err = mapping->a_ops->writepage(page, mpd->wbc);
|
|
if (!err && (pages_skipped == mpd->wbc->pages_skipped))
|
|
/*
|
|
* have successfully written the page
|
|
* without skipping the same
|
|
*/
|
|
mpd->pages_written++;
|
|
/*
|
|
* In error case, we have to continue because
|
|
* remaining pages are still locked
|
|
* XXX: unlock and re-dirty them?
|
|
*/
|
|
if (ret == 0)
|
|
ret = err;
|
|
}
|
|
pagevec_release(&pvec);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
|
|
*
|
|
* @mpd->inode - inode to walk through
|
|
* @exbh->b_blocknr - first block on a disk
|
|
* @exbh->b_size - amount of space in bytes
|
|
* @logical - first logical block to start assignment with
|
|
*
|
|
* the function goes through all passed space and put actual disk
|
|
* block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
|
|
*/
|
|
static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
|
|
struct buffer_head *exbh)
|
|
{
|
|
struct inode *inode = mpd->inode;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
int blocks = exbh->b_size >> inode->i_blkbits;
|
|
sector_t pblock = exbh->b_blocknr, cur_logical;
|
|
struct buffer_head *head, *bh;
|
|
pgoff_t index, end;
|
|
struct pagevec pvec;
|
|
int nr_pages, i;
|
|
|
|
index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
|
|
pagevec_init(&pvec, 0);
|
|
|
|
while (index <= end) {
|
|
/* XXX: optimize tail */
|
|
nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
|
|
if (nr_pages == 0)
|
|
break;
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page = pvec.pages[i];
|
|
|
|
index = page->index;
|
|
if (index > end)
|
|
break;
|
|
index++;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
BUG_ON(PageWriteback(page));
|
|
BUG_ON(!page_has_buffers(page));
|
|
|
|
bh = page_buffers(page);
|
|
head = bh;
|
|
|
|
/* skip blocks out of the range */
|
|
do {
|
|
if (cur_logical >= logical)
|
|
break;
|
|
cur_logical++;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
|
|
do {
|
|
if (cur_logical >= logical + blocks)
|
|
break;
|
|
|
|
if (buffer_delay(bh) ||
|
|
buffer_unwritten(bh)) {
|
|
|
|
BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
|
|
|
|
if (buffer_delay(bh)) {
|
|
clear_buffer_delay(bh);
|
|
bh->b_blocknr = pblock;
|
|
} else {
|
|
/*
|
|
* unwritten already should have
|
|
* blocknr assigned. Verify that
|
|
*/
|
|
clear_buffer_unwritten(bh);
|
|
BUG_ON(bh->b_blocknr != pblock);
|
|
}
|
|
|
|
} else if (buffer_mapped(bh))
|
|
BUG_ON(bh->b_blocknr != pblock);
|
|
|
|
cur_logical++;
|
|
pblock++;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
}
|
|
pagevec_release(&pvec);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* __unmap_underlying_blocks - just a helper function to unmap
|
|
* set of blocks described by @bh
|
|
*/
|
|
static inline void __unmap_underlying_blocks(struct inode *inode,
|
|
struct buffer_head *bh)
|
|
{
|
|
struct block_device *bdev = inode->i_sb->s_bdev;
|
|
int blocks, i;
|
|
|
|
blocks = bh->b_size >> inode->i_blkbits;
|
|
for (i = 0; i < blocks; i++)
|
|
unmap_underlying_metadata(bdev, bh->b_blocknr + i);
|
|
}
|
|
|
|
static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
|
|
sector_t logical, long blk_cnt)
|
|
{
|
|
int nr_pages, i;
|
|
pgoff_t index, end;
|
|
struct pagevec pvec;
|
|
struct inode *inode = mpd->inode;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
|
|
index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
end = (logical + blk_cnt - 1) >>
|
|
(PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
while (index <= end) {
|
|
nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
|
|
if (nr_pages == 0)
|
|
break;
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page = pvec.pages[i];
|
|
index = page->index;
|
|
if (index > end)
|
|
break;
|
|
index++;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
BUG_ON(PageWriteback(page));
|
|
block_invalidatepage(page, 0);
|
|
ClearPageUptodate(page);
|
|
unlock_page(page);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
static void ext4_print_free_blocks(struct inode *inode)
|
|
{
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
printk(KERN_EMERG "Total free blocks count %lld\n",
|
|
ext4_count_free_blocks(inode->i_sb));
|
|
printk(KERN_EMERG "Free/Dirty block details\n");
|
|
printk(KERN_EMERG "free_blocks=%lld\n",
|
|
(long long)percpu_counter_sum(&sbi->s_freeblocks_counter));
|
|
printk(KERN_EMERG "dirty_blocks=%lld\n",
|
|
(long long)percpu_counter_sum(&sbi->s_dirtyblocks_counter));
|
|
printk(KERN_EMERG "Block reservation details\n");
|
|
printk(KERN_EMERG "i_reserved_data_blocks=%u\n",
|
|
EXT4_I(inode)->i_reserved_data_blocks);
|
|
printk(KERN_EMERG "i_reserved_meta_blocks=%u\n",
|
|
EXT4_I(inode)->i_reserved_meta_blocks);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* mpage_da_map_blocks - go through given space
|
|
*
|
|
* @mpd - bh describing space
|
|
*
|
|
* The function skips space we know is already mapped to disk blocks.
|
|
*
|
|
*/
|
|
static int mpage_da_map_blocks(struct mpage_da_data *mpd)
|
|
{
|
|
int err, blks, get_blocks_flags;
|
|
struct buffer_head new;
|
|
sector_t next = mpd->b_blocknr;
|
|
unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
|
|
loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
|
|
handle_t *handle = NULL;
|
|
|
|
/*
|
|
* We consider only non-mapped and non-allocated blocks
|
|
*/
|
|
if ((mpd->b_state & (1 << BH_Mapped)) &&
|
|
!(mpd->b_state & (1 << BH_Delay)) &&
|
|
!(mpd->b_state & (1 << BH_Unwritten)))
|
|
return 0;
|
|
|
|
/*
|
|
* If we didn't accumulate anything to write simply return
|
|
*/
|
|
if (!mpd->b_size)
|
|
return 0;
|
|
|
|
handle = ext4_journal_current_handle();
|
|
BUG_ON(!handle);
|
|
|
|
/*
|
|
* Call ext4_get_blocks() to allocate any delayed allocation
|
|
* blocks, or to convert an uninitialized extent to be
|
|
* initialized (in the case where we have written into
|
|
* one or more preallocated blocks).
|
|
*
|
|
* We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
|
|
* indicate that we are on the delayed allocation path. This
|
|
* affects functions in many different parts of the allocation
|
|
* call path. This flag exists primarily because we don't
|
|
* want to change *many* call functions, so ext4_get_blocks()
|
|
* will set the magic i_delalloc_reserved_flag once the
|
|
* inode's allocation semaphore is taken.
|
|
*
|
|
* If the blocks in questions were delalloc blocks, set
|
|
* EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
|
|
* variables are updated after the blocks have been allocated.
|
|
*/
|
|
new.b_state = 0;
|
|
get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
|
|
EXT4_GET_BLOCKS_DELALLOC_RESERVE);
|
|
if (mpd->b_state & (1 << BH_Delay))
|
|
get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
|
|
blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
|
|
&new, get_blocks_flags);
|
|
if (blks < 0) {
|
|
err = blks;
|
|
/*
|
|
* If get block returns with error we simply
|
|
* return. Later writepage will redirty the page and
|
|
* writepages will find the dirty page again
|
|
*/
|
|
if (err == -EAGAIN)
|
|
return 0;
|
|
|
|
if (err == -ENOSPC &&
|
|
ext4_count_free_blocks(mpd->inode->i_sb)) {
|
|
mpd->retval = err;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* get block failure will cause us to loop in
|
|
* writepages, because a_ops->writepage won't be able
|
|
* to make progress. The page will be redirtied by
|
|
* writepage and writepages will again try to write
|
|
* the same.
|
|
*/
|
|
printk(KERN_EMERG "%s block allocation failed for inode %lu "
|
|
"at logical offset %llu with max blocks "
|
|
"%zd with error %d\n",
|
|
__func__, mpd->inode->i_ino,
|
|
(unsigned long long)next,
|
|
mpd->b_size >> mpd->inode->i_blkbits, err);
|
|
printk(KERN_EMERG "This should not happen.!! "
|
|
"Data will be lost\n");
|
|
if (err == -ENOSPC) {
|
|
ext4_print_free_blocks(mpd->inode);
|
|
}
|
|
/* invalidate all the pages */
|
|
ext4_da_block_invalidatepages(mpd, next,
|
|
mpd->b_size >> mpd->inode->i_blkbits);
|
|
return err;
|
|
}
|
|
BUG_ON(blks == 0);
|
|
|
|
new.b_size = (blks << mpd->inode->i_blkbits);
|
|
|
|
if (buffer_new(&new))
|
|
__unmap_underlying_blocks(mpd->inode, &new);
|
|
|
|
/*
|
|
* If blocks are delayed marked, we need to
|
|
* put actual blocknr and drop delayed bit
|
|
*/
|
|
if ((mpd->b_state & (1 << BH_Delay)) ||
|
|
(mpd->b_state & (1 << BH_Unwritten)))
|
|
mpage_put_bnr_to_bhs(mpd, next, &new);
|
|
|
|
if (ext4_should_order_data(mpd->inode)) {
|
|
err = ext4_jbd2_file_inode(handle, mpd->inode);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Update on-disk size along with block allocation.
|
|
*/
|
|
disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
|
|
if (disksize > i_size_read(mpd->inode))
|
|
disksize = i_size_read(mpd->inode);
|
|
if (disksize > EXT4_I(mpd->inode)->i_disksize) {
|
|
ext4_update_i_disksize(mpd->inode, disksize);
|
|
return ext4_mark_inode_dirty(handle, mpd->inode);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
|
|
(1 << BH_Delay) | (1 << BH_Unwritten))
|
|
|
|
/*
|
|
* mpage_add_bh_to_extent - try to add one more block to extent of blocks
|
|
*
|
|
* @mpd->lbh - extent of blocks
|
|
* @logical - logical number of the block in the file
|
|
* @bh - bh of the block (used to access block's state)
|
|
*
|
|
* the function is used to collect contig. blocks in same state
|
|
*/
|
|
static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
|
|
sector_t logical, size_t b_size,
|
|
unsigned long b_state)
|
|
{
|
|
sector_t next;
|
|
int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
|
|
|
|
/* check if thereserved journal credits might overflow */
|
|
if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
|
|
if (nrblocks >= EXT4_MAX_TRANS_DATA) {
|
|
/*
|
|
* With non-extent format we are limited by the journal
|
|
* credit available. Total credit needed to insert
|
|
* nrblocks contiguous blocks is dependent on the
|
|
* nrblocks. So limit nrblocks.
|
|
*/
|
|
goto flush_it;
|
|
} else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
|
|
EXT4_MAX_TRANS_DATA) {
|
|
/*
|
|
* Adding the new buffer_head would make it cross the
|
|
* allowed limit for which we have journal credit
|
|
* reserved. So limit the new bh->b_size
|
|
*/
|
|
b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
|
|
mpd->inode->i_blkbits;
|
|
/* we will do mpage_da_submit_io in the next loop */
|
|
}
|
|
}
|
|
/*
|
|
* First block in the extent
|
|
*/
|
|
if (mpd->b_size == 0) {
|
|
mpd->b_blocknr = logical;
|
|
mpd->b_size = b_size;
|
|
mpd->b_state = b_state & BH_FLAGS;
|
|
return;
|
|
}
|
|
|
|
next = mpd->b_blocknr + nrblocks;
|
|
/*
|
|
* Can we merge the block to our big extent?
|
|
*/
|
|
if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
|
|
mpd->b_size += b_size;
|
|
return;
|
|
}
|
|
|
|
flush_it:
|
|
/*
|
|
* We couldn't merge the block to our extent, so we
|
|
* need to flush current extent and start new one
|
|
*/
|
|
if (mpage_da_map_blocks(mpd) == 0)
|
|
mpage_da_submit_io(mpd);
|
|
mpd->io_done = 1;
|
|
return;
|
|
}
|
|
|
|
static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
/*
|
|
* unmapped buffer is possible for holes.
|
|
* delay buffer is possible with delayed allocation.
|
|
* We also need to consider unwritten buffer as unmapped.
|
|
*/
|
|
return (!buffer_mapped(bh) || buffer_delay(bh) ||
|
|
buffer_unwritten(bh)) && buffer_dirty(bh);
|
|
}
|
|
|
|
/*
|
|
* __mpage_da_writepage - finds extent of pages and blocks
|
|
*
|
|
* @page: page to consider
|
|
* @wbc: not used, we just follow rules
|
|
* @data: context
|
|
*
|
|
* The function finds extents of pages and scan them for all blocks.
|
|
*/
|
|
static int __mpage_da_writepage(struct page *page,
|
|
struct writeback_control *wbc, void *data)
|
|
{
|
|
struct mpage_da_data *mpd = data;
|
|
struct inode *inode = mpd->inode;
|
|
struct buffer_head *bh, *head;
|
|
sector_t logical;
|
|
|
|
if (mpd->io_done) {
|
|
/*
|
|
* Rest of the page in the page_vec
|
|
* redirty then and skip then. We will
|
|
* try to to write them again after
|
|
* starting a new transaction
|
|
*/
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return MPAGE_DA_EXTENT_TAIL;
|
|
}
|
|
/*
|
|
* Can we merge this page to current extent?
|
|
*/
|
|
if (mpd->next_page != page->index) {
|
|
/*
|
|
* Nope, we can't. So, we map non-allocated blocks
|
|
* and start IO on them using writepage()
|
|
*/
|
|
if (mpd->next_page != mpd->first_page) {
|
|
if (mpage_da_map_blocks(mpd) == 0)
|
|
mpage_da_submit_io(mpd);
|
|
/*
|
|
* skip rest of the page in the page_vec
|
|
*/
|
|
mpd->io_done = 1;
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return MPAGE_DA_EXTENT_TAIL;
|
|
}
|
|
|
|
/*
|
|
* Start next extent of pages ...
|
|
*/
|
|
mpd->first_page = page->index;
|
|
|
|
/*
|
|
* ... and blocks
|
|
*/
|
|
mpd->b_size = 0;
|
|
mpd->b_state = 0;
|
|
mpd->b_blocknr = 0;
|
|
}
|
|
|
|
mpd->next_page = page->index + 1;
|
|
logical = (sector_t) page->index <<
|
|
(PAGE_CACHE_SHIFT - inode->i_blkbits);
|
|
|
|
if (!page_has_buffers(page)) {
|
|
mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
|
|
(1 << BH_Dirty) | (1 << BH_Uptodate));
|
|
if (mpd->io_done)
|
|
return MPAGE_DA_EXTENT_TAIL;
|
|
} else {
|
|
/*
|
|
* Page with regular buffer heads, just add all dirty ones
|
|
*/
|
|
head = page_buffers(page);
|
|
bh = head;
|
|
do {
|
|
BUG_ON(buffer_locked(bh));
|
|
/*
|
|
* We need to try to allocate
|
|
* unmapped blocks in the same page.
|
|
* Otherwise we won't make progress
|
|
* with the page in ext4_da_writepage
|
|
*/
|
|
if (ext4_bh_unmapped_or_delay(NULL, bh)) {
|
|
mpage_add_bh_to_extent(mpd, logical,
|
|
bh->b_size,
|
|
bh->b_state);
|
|
if (mpd->io_done)
|
|
return MPAGE_DA_EXTENT_TAIL;
|
|
} else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
|
|
/*
|
|
* mapped dirty buffer. We need to update
|
|
* the b_state because we look at
|
|
* b_state in mpage_da_map_blocks. We don't
|
|
* update b_size because if we find an
|
|
* unmapped buffer_head later we need to
|
|
* use the b_state flag of that buffer_head.
|
|
*/
|
|
if (mpd->b_size == 0)
|
|
mpd->b_state = bh->b_state & BH_FLAGS;
|
|
}
|
|
logical++;
|
|
} while ((bh = bh->b_this_page) != head);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This is a special get_blocks_t callback which is used by
|
|
* ext4_da_write_begin(). It will either return mapped block or
|
|
* reserve space for a single block.
|
|
*
|
|
* For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
|
|
* We also have b_blocknr = -1 and b_bdev initialized properly
|
|
*
|
|
* For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
|
|
* We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
|
|
* initialized properly.
|
|
*/
|
|
static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
|
|
struct buffer_head *bh_result, int create)
|
|
{
|
|
int ret = 0;
|
|
sector_t invalid_block = ~((sector_t) 0xffff);
|
|
|
|
if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
|
|
invalid_block = ~0;
|
|
|
|
BUG_ON(create == 0);
|
|
BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
|
|
|
|
/*
|
|
* first, we need to know whether the block is allocated already
|
|
* preallocated blocks are unmapped but should treated
|
|
* the same as allocated blocks.
|
|
*/
|
|
ret = ext4_get_blocks(NULL, inode, iblock, 1, bh_result, 0);
|
|
if ((ret == 0) && !buffer_delay(bh_result)) {
|
|
/* the block isn't (pre)allocated yet, let's reserve space */
|
|
/*
|
|
* XXX: __block_prepare_write() unmaps passed block,
|
|
* is it OK?
|
|
*/
|
|
ret = ext4_da_reserve_space(inode, 1);
|
|
if (ret)
|
|
/* not enough space to reserve */
|
|
return ret;
|
|
|
|
map_bh(bh_result, inode->i_sb, invalid_block);
|
|
set_buffer_new(bh_result);
|
|
set_buffer_delay(bh_result);
|
|
} else if (ret > 0) {
|
|
bh_result->b_size = (ret << inode->i_blkbits);
|
|
if (buffer_unwritten(bh_result)) {
|
|
/* A delayed write to unwritten bh should
|
|
* be marked new and mapped. Mapped ensures
|
|
* that we don't do get_block multiple times
|
|
* when we write to the same offset and new
|
|
* ensures that we do proper zero out for
|
|
* partial write.
|
|
*/
|
|
set_buffer_new(bh_result);
|
|
set_buffer_mapped(bh_result);
|
|
}
|
|
ret = 0;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This function is used as a standard get_block_t calback function
|
|
* when there is no desire to allocate any blocks. It is used as a
|
|
* callback function for block_prepare_write(), nobh_writepage(), and
|
|
* block_write_full_page(). These functions should only try to map a
|
|
* single block at a time.
|
|
*
|
|
* Since this function doesn't do block allocations even if the caller
|
|
* requests it by passing in create=1, it is critically important that
|
|
* any caller checks to make sure that any buffer heads are returned
|
|
* by this function are either all already mapped or marked for
|
|
* delayed allocation before calling nobh_writepage() or
|
|
* block_write_full_page(). Otherwise, b_blocknr could be left
|
|
* unitialized, and the page write functions will be taken by
|
|
* surprise.
|
|
*/
|
|
static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
|
|
struct buffer_head *bh_result, int create)
|
|
{
|
|
int ret = 0;
|
|
unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
|
|
|
|
BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
|
|
|
|
/*
|
|
* we don't want to do block allocation in writepage
|
|
* so call get_block_wrap with create = 0
|
|
*/
|
|
ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
|
|
BUG_ON(create && ret == 0);
|
|
if (ret > 0) {
|
|
bh_result->b_size = (ret << inode->i_blkbits);
|
|
ret = 0;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This function can get called via...
|
|
* - ext4_da_writepages after taking page lock (have journal handle)
|
|
* - journal_submit_inode_data_buffers (no journal handle)
|
|
* - shrink_page_list via pdflush (no journal handle)
|
|
* - grab_page_cache when doing write_begin (have journal handle)
|
|
*/
|
|
static int ext4_da_writepage(struct page *page,
|
|
struct writeback_control *wbc)
|
|
{
|
|
int ret = 0;
|
|
loff_t size;
|
|
unsigned int len;
|
|
struct buffer_head *page_bufs;
|
|
struct inode *inode = page->mapping->host;
|
|
|
|
trace_mark(ext4_da_writepage,
|
|
"dev %s ino %lu page_index %lu",
|
|
inode->i_sb->s_id, inode->i_ino, page->index);
|
|
size = i_size_read(inode);
|
|
if (page->index == size >> PAGE_CACHE_SHIFT)
|
|
len = size & ~PAGE_CACHE_MASK;
|
|
else
|
|
len = PAGE_CACHE_SIZE;
|
|
|
|
if (page_has_buffers(page)) {
|
|
page_bufs = page_buffers(page);
|
|
if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
|
|
ext4_bh_unmapped_or_delay)) {
|
|
/*
|
|
* We don't want to do block allocation
|
|
* So redirty the page and return
|
|
* We may reach here when we do a journal commit
|
|
* via journal_submit_inode_data_buffers.
|
|
* If we don't have mapping block we just ignore
|
|
* them. We can also reach here via shrink_page_list
|
|
*/
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
} else {
|
|
/*
|
|
* The test for page_has_buffers() is subtle:
|
|
* We know the page is dirty but it lost buffers. That means
|
|
* that at some moment in time after write_begin()/write_end()
|
|
* has been called all buffers have been clean and thus they
|
|
* must have been written at least once. So they are all
|
|
* mapped and we can happily proceed with mapping them
|
|
* and writing the page.
|
|
*
|
|
* Try to initialize the buffer_heads and check whether
|
|
* all are mapped and non delay. We don't want to
|
|
* do block allocation here.
|
|
*/
|
|
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
|
|
noalloc_get_block_write);
|
|
if (!ret) {
|
|
page_bufs = page_buffers(page);
|
|
/* check whether all are mapped and non delay */
|
|
if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
|
|
ext4_bh_unmapped_or_delay)) {
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
} else {
|
|
/*
|
|
* We can't do block allocation here
|
|
* so just redity the page and unlock
|
|
* and return
|
|
*/
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
/* now mark the buffer_heads as dirty and uptodate */
|
|
block_commit_write(page, 0, PAGE_CACHE_SIZE);
|
|
}
|
|
|
|
if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
|
|
ret = nobh_writepage(page, noalloc_get_block_write, wbc);
|
|
else
|
|
ret = block_write_full_page(page, noalloc_get_block_write,
|
|
wbc);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This is called via ext4_da_writepages() to
|
|
* calulate the total number of credits to reserve to fit
|
|
* a single extent allocation into a single transaction,
|
|
* ext4_da_writpeages() will loop calling this before
|
|
* the block allocation.
|
|
*/
|
|
|
|
static int ext4_da_writepages_trans_blocks(struct inode *inode)
|
|
{
|
|
int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
|
|
|
|
/*
|
|
* With non-extent format the journal credit needed to
|
|
* insert nrblocks contiguous block is dependent on
|
|
* number of contiguous block. So we will limit
|
|
* number of contiguous block to a sane value
|
|
*/
|
|
if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
|
|
(max_blocks > EXT4_MAX_TRANS_DATA))
|
|
max_blocks = EXT4_MAX_TRANS_DATA;
|
|
|
|
return ext4_chunk_trans_blocks(inode, max_blocks);
|
|
}
|
|
|
|
static int ext4_da_writepages(struct address_space *mapping,
|
|
struct writeback_control *wbc)
|
|
{
|
|
pgoff_t index;
|
|
int range_whole = 0;
|
|
handle_t *handle = NULL;
|
|
struct mpage_da_data mpd;
|
|
struct inode *inode = mapping->host;
|
|
int no_nrwrite_index_update;
|
|
int pages_written = 0;
|
|
long pages_skipped;
|
|
int range_cyclic, cycled = 1, io_done = 0;
|
|
int needed_blocks, ret = 0, nr_to_writebump = 0;
|
|
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
|
|
|
|
trace_mark(ext4_da_writepages,
|
|
"dev %s ino %lu nr_t_write %ld "
|
|
"pages_skipped %ld range_start %llu "
|
|
"range_end %llu nonblocking %d "
|
|
"for_kupdate %d for_reclaim %d "
|
|
"for_writepages %d range_cyclic %d",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
wbc->nr_to_write, wbc->pages_skipped,
|
|
(unsigned long long) wbc->range_start,
|
|
(unsigned long long) wbc->range_end,
|
|
wbc->nonblocking, wbc->for_kupdate,
|
|
wbc->for_reclaim, wbc->for_writepages,
|
|
wbc->range_cyclic);
|
|
|
|
/*
|
|
* No pages to write? This is mainly a kludge to avoid starting
|
|
* a transaction for special inodes like journal inode on last iput()
|
|
* because that could violate lock ordering on umount
|
|
*/
|
|
if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
|
|
return 0;
|
|
|
|
/*
|
|
* If the filesystem has aborted, it is read-only, so return
|
|
* right away instead of dumping stack traces later on that
|
|
* will obscure the real source of the problem. We test
|
|
* EXT4_MOUNT_ABORT instead of sb->s_flag's MS_RDONLY because
|
|
* the latter could be true if the filesystem is mounted
|
|
* read-only, and in that case, ext4_da_writepages should
|
|
* *never* be called, so if that ever happens, we would want
|
|
* the stack trace.
|
|
*/
|
|
if (unlikely(sbi->s_mount_opt & EXT4_MOUNT_ABORT))
|
|
return -EROFS;
|
|
|
|
/*
|
|
* Make sure nr_to_write is >= sbi->s_mb_stream_request
|
|
* This make sure small files blocks are allocated in
|
|
* single attempt. This ensure that small files
|
|
* get less fragmented.
|
|
*/
|
|
if (wbc->nr_to_write < sbi->s_mb_stream_request) {
|
|
nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
|
|
wbc->nr_to_write = sbi->s_mb_stream_request;
|
|
}
|
|
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
|
|
range_whole = 1;
|
|
|
|
range_cyclic = wbc->range_cyclic;
|
|
if (wbc->range_cyclic) {
|
|
index = mapping->writeback_index;
|
|
if (index)
|
|
cycled = 0;
|
|
wbc->range_start = index << PAGE_CACHE_SHIFT;
|
|
wbc->range_end = LLONG_MAX;
|
|
wbc->range_cyclic = 0;
|
|
} else
|
|
index = wbc->range_start >> PAGE_CACHE_SHIFT;
|
|
|
|
mpd.wbc = wbc;
|
|
mpd.inode = mapping->host;
|
|
|
|
/*
|
|
* we don't want write_cache_pages to update
|
|
* nr_to_write and writeback_index
|
|
*/
|
|
no_nrwrite_index_update = wbc->no_nrwrite_index_update;
|
|
wbc->no_nrwrite_index_update = 1;
|
|
pages_skipped = wbc->pages_skipped;
|
|
|
|
retry:
|
|
while (!ret && wbc->nr_to_write > 0) {
|
|
|
|
/*
|
|
* we insert one extent at a time. So we need
|
|
* credit needed for single extent allocation.
|
|
* journalled mode is currently not supported
|
|
* by delalloc
|
|
*/
|
|
BUG_ON(ext4_should_journal_data(inode));
|
|
needed_blocks = ext4_da_writepages_trans_blocks(inode);
|
|
|
|
/* start a new transaction*/
|
|
handle = ext4_journal_start(inode, needed_blocks);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
printk(KERN_CRIT "%s: jbd2_start: "
|
|
"%ld pages, ino %lu; err %d\n", __func__,
|
|
wbc->nr_to_write, inode->i_ino, ret);
|
|
dump_stack();
|
|
goto out_writepages;
|
|
}
|
|
|
|
/*
|
|
* Now call __mpage_da_writepage to find the next
|
|
* contiguous region of logical blocks that need
|
|
* blocks to be allocated by ext4. We don't actually
|
|
* submit the blocks for I/O here, even though
|
|
* write_cache_pages thinks it will, and will set the
|
|
* pages as clean for write before calling
|
|
* __mpage_da_writepage().
|
|
*/
|
|
mpd.b_size = 0;
|
|
mpd.b_state = 0;
|
|
mpd.b_blocknr = 0;
|
|
mpd.first_page = 0;
|
|
mpd.next_page = 0;
|
|
mpd.io_done = 0;
|
|
mpd.pages_written = 0;
|
|
mpd.retval = 0;
|
|
ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
|
|
&mpd);
|
|
/*
|
|
* If we have a contigous extent of pages and we
|
|
* haven't done the I/O yet, map the blocks and submit
|
|
* them for I/O.
|
|
*/
|
|
if (!mpd.io_done && mpd.next_page != mpd.first_page) {
|
|
if (mpage_da_map_blocks(&mpd) == 0)
|
|
mpage_da_submit_io(&mpd);
|
|
mpd.io_done = 1;
|
|
ret = MPAGE_DA_EXTENT_TAIL;
|
|
}
|
|
wbc->nr_to_write -= mpd.pages_written;
|
|
|
|
ext4_journal_stop(handle);
|
|
|
|
if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
|
|
/* commit the transaction which would
|
|
* free blocks released in the transaction
|
|
* and try again
|
|
*/
|
|
jbd2_journal_force_commit_nested(sbi->s_journal);
|
|
wbc->pages_skipped = pages_skipped;
|
|
ret = 0;
|
|
} else if (ret == MPAGE_DA_EXTENT_TAIL) {
|
|
/*
|
|
* got one extent now try with
|
|
* rest of the pages
|
|
*/
|
|
pages_written += mpd.pages_written;
|
|
wbc->pages_skipped = pages_skipped;
|
|
ret = 0;
|
|
io_done = 1;
|
|
} else if (wbc->nr_to_write)
|
|
/*
|
|
* There is no more writeout needed
|
|
* or we requested for a noblocking writeout
|
|
* and we found the device congested
|
|
*/
|
|
break;
|
|
}
|
|
if (!io_done && !cycled) {
|
|
cycled = 1;
|
|
index = 0;
|
|
wbc->range_start = index << PAGE_CACHE_SHIFT;
|
|
wbc->range_end = mapping->writeback_index - 1;
|
|
goto retry;
|
|
}
|
|
if (pages_skipped != wbc->pages_skipped)
|
|
printk(KERN_EMERG "This should not happen leaving %s "
|
|
"with nr_to_write = %ld ret = %d\n",
|
|
__func__, wbc->nr_to_write, ret);
|
|
|
|
/* Update index */
|
|
index += pages_written;
|
|
wbc->range_cyclic = range_cyclic;
|
|
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
|
|
/*
|
|
* set the writeback_index so that range_cyclic
|
|
* mode will write it back later
|
|
*/
|
|
mapping->writeback_index = index;
|
|
|
|
out_writepages:
|
|
if (!no_nrwrite_index_update)
|
|
wbc->no_nrwrite_index_update = 0;
|
|
wbc->nr_to_write -= nr_to_writebump;
|
|
trace_mark(ext4_da_writepage_result,
|
|
"dev %s ino %lu ret %d pages_written %d "
|
|
"pages_skipped %ld congestion %d "
|
|
"more_io %d no_nrwrite_index_update %d",
|
|
inode->i_sb->s_id, inode->i_ino, ret,
|
|
pages_written, wbc->pages_skipped,
|
|
wbc->encountered_congestion, wbc->more_io,
|
|
wbc->no_nrwrite_index_update);
|
|
return ret;
|
|
}
|
|
|
|
#define FALL_BACK_TO_NONDELALLOC 1
|
|
static int ext4_nonda_switch(struct super_block *sb)
|
|
{
|
|
s64 free_blocks, dirty_blocks;
|
|
struct ext4_sb_info *sbi = EXT4_SB(sb);
|
|
|
|
/*
|
|
* switch to non delalloc mode if we are running low
|
|
* on free block. The free block accounting via percpu
|
|
* counters can get slightly wrong with percpu_counter_batch getting
|
|
* accumulated on each CPU without updating global counters
|
|
* Delalloc need an accurate free block accounting. So switch
|
|
* to non delalloc when we are near to error range.
|
|
*/
|
|
free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
|
|
dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
|
|
if (2 * free_blocks < 3 * dirty_blocks ||
|
|
free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
|
|
/*
|
|
* free block count is less that 150% of dirty blocks
|
|
* or free blocks is less that watermark
|
|
*/
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned flags,
|
|
struct page **pagep, void **fsdata)
|
|
{
|
|
int ret, retries = 0;
|
|
struct page *page;
|
|
pgoff_t index;
|
|
unsigned from, to;
|
|
struct inode *inode = mapping->host;
|
|
handle_t *handle;
|
|
|
|
index = pos >> PAGE_CACHE_SHIFT;
|
|
from = pos & (PAGE_CACHE_SIZE - 1);
|
|
to = from + len;
|
|
|
|
if (ext4_nonda_switch(inode->i_sb)) {
|
|
*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
|
|
return ext4_write_begin(file, mapping, pos,
|
|
len, flags, pagep, fsdata);
|
|
}
|
|
*fsdata = (void *)0;
|
|
|
|
trace_mark(ext4_da_write_begin,
|
|
"dev %s ino %lu pos %llu len %u flags %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, flags);
|
|
retry:
|
|
/*
|
|
* With delayed allocation, we don't log the i_disksize update
|
|
* if there is delayed block allocation. But we still need
|
|
* to journalling the i_disksize update if writes to the end
|
|
* of file which has an already mapped buffer.
|
|
*/
|
|
handle = ext4_journal_start(inode, 1);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
/* We cannot recurse into the filesystem as the transaction is already
|
|
* started */
|
|
flags |= AOP_FLAG_NOFS;
|
|
|
|
page = grab_cache_page_write_begin(mapping, index, flags);
|
|
if (!page) {
|
|
ext4_journal_stop(handle);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
*pagep = page;
|
|
|
|
ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
|
|
ext4_da_get_block_prep);
|
|
if (ret < 0) {
|
|
unlock_page(page);
|
|
ext4_journal_stop(handle);
|
|
page_cache_release(page);
|
|
/*
|
|
* block_write_begin may have instantiated a few blocks
|
|
* outside i_size. Trim these off again. Don't need
|
|
* i_size_read because we hold i_mutex.
|
|
*/
|
|
if (pos + len > inode->i_size)
|
|
vmtruncate(inode, inode->i_size);
|
|
}
|
|
|
|
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
|
|
goto retry;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Check if we should update i_disksize
|
|
* when write to the end of file but not require block allocation
|
|
*/
|
|
static int ext4_da_should_update_i_disksize(struct page *page,
|
|
unsigned long offset)
|
|
{
|
|
struct buffer_head *bh;
|
|
struct inode *inode = page->mapping->host;
|
|
unsigned int idx;
|
|
int i;
|
|
|
|
bh = page_buffers(page);
|
|
idx = offset >> inode->i_blkbits;
|
|
|
|
for (i = 0; i < idx; i++)
|
|
bh = bh->b_this_page;
|
|
|
|
if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static int ext4_da_write_end(struct file *file,
|
|
struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
int ret = 0, ret2;
|
|
handle_t *handle = ext4_journal_current_handle();
|
|
loff_t new_i_size;
|
|
unsigned long start, end;
|
|
int write_mode = (int)(unsigned long)fsdata;
|
|
|
|
if (write_mode == FALL_BACK_TO_NONDELALLOC) {
|
|
if (ext4_should_order_data(inode)) {
|
|
return ext4_ordered_write_end(file, mapping, pos,
|
|
len, copied, page, fsdata);
|
|
} else if (ext4_should_writeback_data(inode)) {
|
|
return ext4_writeback_write_end(file, mapping, pos,
|
|
len, copied, page, fsdata);
|
|
} else {
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
trace_mark(ext4_da_write_end,
|
|
"dev %s ino %lu pos %llu len %u copied %u",
|
|
inode->i_sb->s_id, inode->i_ino,
|
|
(unsigned long long) pos, len, copied);
|
|
start = pos & (PAGE_CACHE_SIZE - 1);
|
|
end = start + copied - 1;
|
|
|
|
/*
|
|
* generic_write_end() will run mark_inode_dirty() if i_size
|
|
* changes. So let's piggyback the i_disksize mark_inode_dirty
|
|
* into that.
|
|
*/
|
|
|
|
new_i_size = pos + copied;
|
|
if (new_i_size > EXT4_I(inode)->i_disksize) {
|
|
if (ext4_da_should_update_i_disksize(page, end)) {
|
|
down_write(&EXT4_I(inode)->i_data_sem);
|
|
if (new_i_size > EXT4_I(inode)->i_disksize) {
|
|
/*
|
|
* Updating i_disksize when extending file
|
|
* without needing block allocation
|
|
*/
|
|
if (ext4_should_order_data(inode))
|
|
ret = ext4_jbd2_file_inode(handle,
|
|
inode);
|
|
|
|
EXT4_I(inode)->i_disksize = new_i_size;
|
|
}
|
|
up_write(&EXT4_I(inode)->i_data_sem);
|
|
/* We need to mark inode dirty even if
|
|
* new_i_size is less that inode->i_size
|
|
* bu greater than i_disksize.(hint delalloc)
|
|
*/
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
}
|
|
}
|
|
ret2 = generic_write_end(file, mapping, pos, len, copied,
|
|
page, fsdata);
|
|
copied = ret2;
|
|
if (ret2 < 0)
|
|
ret = ret2;
|
|
ret2 = ext4_journal_stop(handle);
|
|
if (!ret)
|
|
ret = ret2;
|
|
|
|
return ret ? ret : copied;
|
|
}
|
|
|
|
static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
|
|
{
|
|
/*
|
|
* Drop reserved blocks
|
|
*/
|
|
BUG_ON(!PageLocked(page));
|
|
if (!page_has_buffers(page))
|
|
goto out;
|
|
|
|
ext4_da_page_release_reservation(page, offset);
|
|
|
|
out:
|
|
ext4_invalidatepage(page, offset);
|
|
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Force all delayed allocation blocks to be allocated for a given inode.
|
|
*/
|
|
int ext4_alloc_da_blocks(struct inode *inode)
|
|
{
|
|
if (!EXT4_I(inode)->i_reserved_data_blocks &&
|
|
!EXT4_I(inode)->i_reserved_meta_blocks)
|
|
return 0;
|
|
|
|
/*
|
|
* We do something simple for now. The filemap_flush() will
|
|
* also start triggering a write of the data blocks, which is
|
|
* not strictly speaking necessary (and for users of
|
|
* laptop_mode, not even desirable). However, to do otherwise
|
|
* would require replicating code paths in:
|
|
*
|
|
* ext4_da_writepages() ->
|
|
* write_cache_pages() ---> (via passed in callback function)
|
|
* __mpage_da_writepage() -->
|
|
* mpage_add_bh_to_extent()
|
|
* mpage_da_map_blocks()
|
|
*
|
|
* The problem is that write_cache_pages(), located in
|
|
* mm/page-writeback.c, marks pages clean in preparation for
|
|
* doing I/O, which is not desirable if we're not planning on
|
|
* doing I/O at all.
|
|
*
|
|
* We could call write_cache_pages(), and then redirty all of
|
|
* the pages by calling redirty_page_for_writeback() but that
|
|
* would be ugly in the extreme. So instead we would need to
|
|
* replicate parts of the code in the above functions,
|
|
* simplifying them becuase we wouldn't actually intend to
|
|
* write out the pages, but rather only collect contiguous
|
|
* logical block extents, call the multi-block allocator, and
|
|
* then update the buffer heads with the block allocations.
|
|
*
|
|
* For now, though, we'll cheat by calling filemap_flush(),
|
|
* which will map the blocks, and start the I/O, but not
|
|
* actually wait for the I/O to complete.
|
|
*/
|
|
return filemap_flush(inode->i_mapping);
|
|
}
|
|
|
|
/*
|
|
* bmap() is special. It gets used by applications such as lilo and by
|
|
* the swapper to find the on-disk block of a specific piece of data.
|
|
*
|
|
* Naturally, this is dangerous if the block concerned is still in the
|
|
* journal. If somebody makes a swapfile on an ext4 data-journaling
|
|
* filesystem and enables swap, then they may get a nasty shock when the
|
|
* data getting swapped to that swapfile suddenly gets overwritten by
|
|
* the original zero's written out previously to the journal and
|
|
* awaiting writeback in the kernel's buffer cache.
|
|
*
|
|
* So, if we see any bmap calls here on a modified, data-journaled file,
|
|
* take extra steps to flush any blocks which might be in the cache.
|
|
*/
|
|
static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
journal_t *journal;
|
|
int err;
|
|
|
|
if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
|
|
test_opt(inode->i_sb, DELALLOC)) {
|
|
/*
|
|
* With delalloc we want to sync the file
|
|
* so that we can make sure we allocate
|
|
* blocks for file
|
|
*/
|
|
filemap_write_and_wait(mapping);
|
|
}
|
|
|
|
if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
|
|
/*
|
|
* This is a REALLY heavyweight approach, but the use of
|
|
* bmap on dirty files is expected to be extremely rare:
|
|
* only if we run lilo or swapon on a freshly made file
|
|
* do we expect this to happen.
|
|
*
|
|
* (bmap requires CAP_SYS_RAWIO so this does not
|
|
* represent an unprivileged user DOS attack --- we'd be
|
|
* in trouble if mortal users could trigger this path at
|
|
* will.)
|
|
*
|
|
* NB. EXT4_STATE_JDATA is not set on files other than
|
|
* regular files. If somebody wants to bmap a directory
|
|
* or symlink and gets confused because the buffer
|
|
* hasn't yet been flushed to disk, they deserve
|
|
* everything they get.
|
|
*/
|
|
|
|
EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
|
|
journal = EXT4_JOURNAL(inode);
|
|
jbd2_journal_lock_updates(journal);
|
|
err = jbd2_journal_flush(journal);
|
|
jbd2_journal_unlock_updates(journal);
|
|
|
|
if (err)
|
|
return 0;
|
|
}
|
|
|
|
return generic_block_bmap(mapping, block, ext4_get_block);
|
|
}
|
|
|
|
static int bget_one(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
get_bh(bh);
|
|
return 0;
|
|
}
|
|
|
|
static int bput_one(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
put_bh(bh);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Note that we don't need to start a transaction unless we're journaling data
|
|
* because we should have holes filled from ext4_page_mkwrite(). We even don't
|
|
* need to file the inode to the transaction's list in ordered mode because if
|
|
* we are writing back data added by write(), the inode is already there and if
|
|
* we are writing back data modified via mmap(), noone guarantees in which
|
|
* transaction the data will hit the disk. In case we are journaling data, we
|
|
* cannot start transaction directly because transaction start ranks above page
|
|
* lock so we have to do some magic.
|
|
*
|
|
* In all journaling modes block_write_full_page() will start the I/O.
|
|
*
|
|
* Problem:
|
|
*
|
|
* ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
|
|
* ext4_writepage()
|
|
*
|
|
* Similar for:
|
|
*
|
|
* ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
|
|
*
|
|
* Same applies to ext4_get_block(). We will deadlock on various things like
|
|
* lock_journal and i_data_sem
|
|
*
|
|
* Setting PF_MEMALLOC here doesn't work - too many internal memory
|
|
* allocations fail.
|
|
*
|
|
* 16May01: If we're reentered then journal_current_handle() will be
|
|
* non-zero. We simply *return*.
|
|
*
|
|
* 1 July 2001: @@@ FIXME:
|
|
* In journalled data mode, a data buffer may be metadata against the
|
|
* current transaction. But the same file is part of a shared mapping
|
|
* and someone does a writepage() on it.
|
|
*
|
|
* We will move the buffer onto the async_data list, but *after* it has
|
|
* been dirtied. So there's a small window where we have dirty data on
|
|
* BJ_Metadata.
|
|
*
|
|
* Note that this only applies to the last partial page in the file. The
|
|
* bit which block_write_full_page() uses prepare/commit for. (That's
|
|
* broken code anyway: it's wrong for msync()).
|
|
*
|
|
* It's a rare case: affects the final partial page, for journalled data
|
|
* where the file is subject to bith write() and writepage() in the same
|
|
* transction. To fix it we'll need a custom block_write_full_page().
|
|
* We'll probably need that anyway for journalling writepage() output.
|
|
*
|
|
* We don't honour synchronous mounts for writepage(). That would be
|
|
* disastrous. Any write() or metadata operation will sync the fs for
|
|
* us.
|
|
*
|
|
*/
|
|
static int __ext4_normal_writepage(struct page *page,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
|
|
if (test_opt(inode->i_sb, NOBH))
|
|
return nobh_writepage(page, noalloc_get_block_write, wbc);
|
|
else
|
|
return block_write_full_page(page, noalloc_get_block_write,
|
|
wbc);
|
|
}
|
|
|
|
static int ext4_normal_writepage(struct page *page,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
loff_t size = i_size_read(inode);
|
|
loff_t len;
|
|
|
|
trace_mark(ext4_normal_writepage,
|
|
"dev %s ino %lu page_index %lu",
|
|
inode->i_sb->s_id, inode->i_ino, page->index);
|
|
J_ASSERT(PageLocked(page));
|
|
if (page->index == size >> PAGE_CACHE_SHIFT)
|
|
len = size & ~PAGE_CACHE_MASK;
|
|
else
|
|
len = PAGE_CACHE_SIZE;
|
|
|
|
if (page_has_buffers(page)) {
|
|
/* if page has buffers it should all be mapped
|
|
* and allocated. If there are not buffers attached
|
|
* to the page we know the page is dirty but it lost
|
|
* buffers. That means that at some moment in time
|
|
* after write_begin() / write_end() has been called
|
|
* all buffers have been clean and thus they must have been
|
|
* written at least once. So they are all mapped and we can
|
|
* happily proceed with mapping them and writing the page.
|
|
*/
|
|
BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
|
|
ext4_bh_unmapped_or_delay));
|
|
}
|
|
|
|
if (!ext4_journal_current_handle())
|
|
return __ext4_normal_writepage(page, wbc);
|
|
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static int __ext4_journalled_writepage(struct page *page,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct address_space *mapping = page->mapping;
|
|
struct inode *inode = mapping->host;
|
|
struct buffer_head *page_bufs;
|
|
handle_t *handle = NULL;
|
|
int ret = 0;
|
|
int err;
|
|
|
|
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
|
|
noalloc_get_block_write);
|
|
if (ret != 0)
|
|
goto out_unlock;
|
|
|
|
page_bufs = page_buffers(page);
|
|
walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
|
|
bget_one);
|
|
/* As soon as we unlock the page, it can go away, but we have
|
|
* references to buffers so we are safe */
|
|
unlock_page(page);
|
|
|
|
handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
|
|
ret = walk_page_buffers(handle, page_bufs, 0,
|
|
PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
|
|
|
|
err = walk_page_buffers(handle, page_bufs, 0,
|
|
PAGE_CACHE_SIZE, NULL, write_end_fn);
|
|
if (ret == 0)
|
|
ret = err;
|
|
err = ext4_journal_stop(handle);
|
|
if (!ret)
|
|
ret = err;
|
|
|
|
walk_page_buffers(handle, page_bufs, 0,
|
|
PAGE_CACHE_SIZE, NULL, bput_one);
|
|
EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
|
|
goto out;
|
|
|
|
out_unlock:
|
|
unlock_page(page);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int ext4_journalled_writepage(struct page *page,
|
|
struct writeback_control *wbc)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
loff_t size = i_size_read(inode);
|
|
loff_t len;
|
|
|
|
trace_mark(ext4_journalled_writepage,
|
|
"dev %s ino %lu page_index %lu",
|
|
inode->i_sb->s_id, inode->i_ino, page->index);
|
|
J_ASSERT(PageLocked(page));
|
|
if (page->index == size >> PAGE_CACHE_SHIFT)
|
|
len = size & ~PAGE_CACHE_MASK;
|
|
else
|
|
len = PAGE_CACHE_SIZE;
|
|
|
|
if (page_has_buffers(page)) {
|
|
/* if page has buffers it should all be mapped
|
|
* and allocated. If there are not buffers attached
|
|
* to the page we know the page is dirty but it lost
|
|
* buffers. That means that at some moment in time
|
|
* after write_begin() / write_end() has been called
|
|
* all buffers have been clean and thus they must have been
|
|
* written at least once. So they are all mapped and we can
|
|
* happily proceed with mapping them and writing the page.
|
|
*/
|
|
BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
|
|
ext4_bh_unmapped_or_delay));
|
|
}
|
|
|
|
if (ext4_journal_current_handle())
|
|
goto no_write;
|
|
|
|
if (PageChecked(page)) {
|
|
/*
|
|
* It's mmapped pagecache. Add buffers and journal it. There
|
|
* doesn't seem much point in redirtying the page here.
|
|
*/
|
|
ClearPageChecked(page);
|
|
return __ext4_journalled_writepage(page, wbc);
|
|
} else {
|
|
/*
|
|
* It may be a page full of checkpoint-mode buffers. We don't
|
|
* really know unless we go poke around in the buffer_heads.
|
|
* But block_write_full_page will do the right thing.
|
|
*/
|
|
return block_write_full_page(page, noalloc_get_block_write,
|
|
wbc);
|
|
}
|
|
no_write:
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static int ext4_readpage(struct file *file, struct page *page)
|
|
{
|
|
return mpage_readpage(page, ext4_get_block);
|
|
}
|
|
|
|
static int
|
|
ext4_readpages(struct file *file, struct address_space *mapping,
|
|
struct list_head *pages, unsigned nr_pages)
|
|
{
|
|
return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
|
|
}
|
|
|
|
static void ext4_invalidatepage(struct page *page, unsigned long offset)
|
|
{
|
|
journal_t *journal = EXT4_JOURNAL(page->mapping->host);
|
|
|
|
/*
|
|
* If it's a full truncate we just forget about the pending dirtying
|
|
*/
|
|
if (offset == 0)
|
|
ClearPageChecked(page);
|
|
|
|
if (journal)
|
|
jbd2_journal_invalidatepage(journal, page, offset);
|
|
else
|
|
block_invalidatepage(page, offset);
|
|
}
|
|
|
|
static int ext4_releasepage(struct page *page, gfp_t wait)
|
|
{
|
|
journal_t *journal = EXT4_JOURNAL(page->mapping->host);
|
|
|
|
WARN_ON(PageChecked(page));
|
|
if (!page_has_buffers(page))
|
|
return 0;
|
|
if (journal)
|
|
return jbd2_journal_try_to_free_buffers(journal, page, wait);
|
|
else
|
|
return try_to_free_buffers(page);
|
|
}
|
|
|
|
/*
|
|
* If the O_DIRECT write will extend the file then add this inode to the
|
|
* orphan list. So recovery will truncate it back to the original size
|
|
* if the machine crashes during the write.
|
|
*
|
|
* If the O_DIRECT write is intantiating holes inside i_size and the machine
|
|
* crashes then stale disk data _may_ be exposed inside the file. But current
|
|
* VFS code falls back into buffered path in that case so we are safe.
|
|
*/
|
|
static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
|
|
const struct iovec *iov, loff_t offset,
|
|
unsigned long nr_segs)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct inode *inode = file->f_mapping->host;
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
handle_t *handle;
|
|
ssize_t ret;
|
|
int orphan = 0;
|
|
size_t count = iov_length(iov, nr_segs);
|
|
|
|
if (rw == WRITE) {
|
|
loff_t final_size = offset + count;
|
|
|
|
if (final_size > inode->i_size) {
|
|
/* Credits for sb + inode write */
|
|
handle = ext4_journal_start(inode, 2);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
ret = ext4_orphan_add(handle, inode);
|
|
if (ret) {
|
|
ext4_journal_stop(handle);
|
|
goto out;
|
|
}
|
|
orphan = 1;
|
|
ei->i_disksize = inode->i_size;
|
|
ext4_journal_stop(handle);
|
|
}
|
|
}
|
|
|
|
ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
|
|
offset, nr_segs,
|
|
ext4_get_block, NULL);
|
|
|
|
if (orphan) {
|
|
int err;
|
|
|
|
/* Credits for sb + inode write */
|
|
handle = ext4_journal_start(inode, 2);
|
|
if (IS_ERR(handle)) {
|
|
/* This is really bad luck. We've written the data
|
|
* but cannot extend i_size. Bail out and pretend
|
|
* the write failed... */
|
|
ret = PTR_ERR(handle);
|
|
goto out;
|
|
}
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(handle, inode);
|
|
if (ret > 0) {
|
|
loff_t end = offset + ret;
|
|
if (end > inode->i_size) {
|
|
ei->i_disksize = end;
|
|
i_size_write(inode, end);
|
|
/*
|
|
* We're going to return a positive `ret'
|
|
* here due to non-zero-length I/O, so there's
|
|
* no way of reporting error returns from
|
|
* ext4_mark_inode_dirty() to userspace. So
|
|
* ignore it.
|
|
*/
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
}
|
|
}
|
|
err = ext4_journal_stop(handle);
|
|
if (ret == 0)
|
|
ret = err;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Pages can be marked dirty completely asynchronously from ext4's journalling
|
|
* activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
|
|
* much here because ->set_page_dirty is called under VFS locks. The page is
|
|
* not necessarily locked.
|
|
*
|
|
* We cannot just dirty the page and leave attached buffers clean, because the
|
|
* buffers' dirty state is "definitive". We cannot just set the buffers dirty
|
|
* or jbddirty because all the journalling code will explode.
|
|
*
|
|
* So what we do is to mark the page "pending dirty" and next time writepage
|
|
* is called, propagate that into the buffers appropriately.
|
|
*/
|
|
static int ext4_journalled_set_page_dirty(struct page *page)
|
|
{
|
|
SetPageChecked(page);
|
|
return __set_page_dirty_nobuffers(page);
|
|
}
|
|
|
|
static const struct address_space_operations ext4_ordered_aops = {
|
|
.readpage = ext4_readpage,
|
|
.readpages = ext4_readpages,
|
|
.writepage = ext4_normal_writepage,
|
|
.sync_page = block_sync_page,
|
|
.write_begin = ext4_write_begin,
|
|
.write_end = ext4_ordered_write_end,
|
|
.bmap = ext4_bmap,
|
|
.invalidatepage = ext4_invalidatepage,
|
|
.releasepage = ext4_releasepage,
|
|
.direct_IO = ext4_direct_IO,
|
|
.migratepage = buffer_migrate_page,
|
|
.is_partially_uptodate = block_is_partially_uptodate,
|
|
};
|
|
|
|
static const struct address_space_operations ext4_writeback_aops = {
|
|
.readpage = ext4_readpage,
|
|
.readpages = ext4_readpages,
|
|
.writepage = ext4_normal_writepage,
|
|
.sync_page = block_sync_page,
|
|
.write_begin = ext4_write_begin,
|
|
.write_end = ext4_writeback_write_end,
|
|
.bmap = ext4_bmap,
|
|
.invalidatepage = ext4_invalidatepage,
|
|
.releasepage = ext4_releasepage,
|
|
.direct_IO = ext4_direct_IO,
|
|
.migratepage = buffer_migrate_page,
|
|
.is_partially_uptodate = block_is_partially_uptodate,
|
|
};
|
|
|
|
static const struct address_space_operations ext4_journalled_aops = {
|
|
.readpage = ext4_readpage,
|
|
.readpages = ext4_readpages,
|
|
.writepage = ext4_journalled_writepage,
|
|
.sync_page = block_sync_page,
|
|
.write_begin = ext4_write_begin,
|
|
.write_end = ext4_journalled_write_end,
|
|
.set_page_dirty = ext4_journalled_set_page_dirty,
|
|
.bmap = ext4_bmap,
|
|
.invalidatepage = ext4_invalidatepage,
|
|
.releasepage = ext4_releasepage,
|
|
.is_partially_uptodate = block_is_partially_uptodate,
|
|
};
|
|
|
|
static const struct address_space_operations ext4_da_aops = {
|
|
.readpage = ext4_readpage,
|
|
.readpages = ext4_readpages,
|
|
.writepage = ext4_da_writepage,
|
|
.writepages = ext4_da_writepages,
|
|
.sync_page = block_sync_page,
|
|
.write_begin = ext4_da_write_begin,
|
|
.write_end = ext4_da_write_end,
|
|
.bmap = ext4_bmap,
|
|
.invalidatepage = ext4_da_invalidatepage,
|
|
.releasepage = ext4_releasepage,
|
|
.direct_IO = ext4_direct_IO,
|
|
.migratepage = buffer_migrate_page,
|
|
.is_partially_uptodate = block_is_partially_uptodate,
|
|
};
|
|
|
|
void ext4_set_aops(struct inode *inode)
|
|
{
|
|
if (ext4_should_order_data(inode) &&
|
|
test_opt(inode->i_sb, DELALLOC))
|
|
inode->i_mapping->a_ops = &ext4_da_aops;
|
|
else if (ext4_should_order_data(inode))
|
|
inode->i_mapping->a_ops = &ext4_ordered_aops;
|
|
else if (ext4_should_writeback_data(inode) &&
|
|
test_opt(inode->i_sb, DELALLOC))
|
|
inode->i_mapping->a_ops = &ext4_da_aops;
|
|
else if (ext4_should_writeback_data(inode))
|
|
inode->i_mapping->a_ops = &ext4_writeback_aops;
|
|
else
|
|
inode->i_mapping->a_ops = &ext4_journalled_aops;
|
|
}
|
|
|
|
/*
|
|
* ext4_block_truncate_page() zeroes out a mapping from file offset `from'
|
|
* up to the end of the block which corresponds to `from'.
|
|
* This required during truncate. We need to physically zero the tail end
|
|
* of that block so it doesn't yield old data if the file is later grown.
|
|
*/
|
|
int ext4_block_truncate_page(handle_t *handle,
|
|
struct address_space *mapping, loff_t from)
|
|
{
|
|
ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
|
|
unsigned offset = from & (PAGE_CACHE_SIZE-1);
|
|
unsigned blocksize, length, pos;
|
|
ext4_lblk_t iblock;
|
|
struct inode *inode = mapping->host;
|
|
struct buffer_head *bh;
|
|
struct page *page;
|
|
int err = 0;
|
|
|
|
page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
|
|
if (!page)
|
|
return -EINVAL;
|
|
|
|
blocksize = inode->i_sb->s_blocksize;
|
|
length = blocksize - (offset & (blocksize - 1));
|
|
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
|
|
|
|
/*
|
|
* For "nobh" option, we can only work if we don't need to
|
|
* read-in the page - otherwise we create buffers to do the IO.
|
|
*/
|
|
if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
|
|
ext4_should_writeback_data(inode) && PageUptodate(page)) {
|
|
zero_user(page, offset, length);
|
|
set_page_dirty(page);
|
|
goto unlock;
|
|
}
|
|
|
|
if (!page_has_buffers(page))
|
|
create_empty_buffers(page, blocksize, 0);
|
|
|
|
/* Find the buffer that contains "offset" */
|
|
bh = page_buffers(page);
|
|
pos = blocksize;
|
|
while (offset >= pos) {
|
|
bh = bh->b_this_page;
|
|
iblock++;
|
|
pos += blocksize;
|
|
}
|
|
|
|
err = 0;
|
|
if (buffer_freed(bh)) {
|
|
BUFFER_TRACE(bh, "freed: skip");
|
|
goto unlock;
|
|
}
|
|
|
|
if (!buffer_mapped(bh)) {
|
|
BUFFER_TRACE(bh, "unmapped");
|
|
ext4_get_block(inode, iblock, bh, 0);
|
|
/* unmapped? It's a hole - nothing to do */
|
|
if (!buffer_mapped(bh)) {
|
|
BUFFER_TRACE(bh, "still unmapped");
|
|
goto unlock;
|
|
}
|
|
}
|
|
|
|
/* Ok, it's mapped. Make sure it's up-to-date */
|
|
if (PageUptodate(page))
|
|
set_buffer_uptodate(bh);
|
|
|
|
if (!buffer_uptodate(bh)) {
|
|
err = -EIO;
|
|
ll_rw_block(READ, 1, &bh);
|
|
wait_on_buffer(bh);
|
|
/* Uhhuh. Read error. Complain and punt. */
|
|
if (!buffer_uptodate(bh))
|
|
goto unlock;
|
|
}
|
|
|
|
if (ext4_should_journal_data(inode)) {
|
|
BUFFER_TRACE(bh, "get write access");
|
|
err = ext4_journal_get_write_access(handle, bh);
|
|
if (err)
|
|
goto unlock;
|
|
}
|
|
|
|
zero_user(page, offset, length);
|
|
|
|
BUFFER_TRACE(bh, "zeroed end of block");
|
|
|
|
err = 0;
|
|
if (ext4_should_journal_data(inode)) {
|
|
err = ext4_handle_dirty_metadata(handle, inode, bh);
|
|
} else {
|
|
if (ext4_should_order_data(inode))
|
|
err = ext4_jbd2_file_inode(handle, inode);
|
|
mark_buffer_dirty(bh);
|
|
}
|
|
|
|
unlock:
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Probably it should be a library function... search for first non-zero word
|
|
* or memcmp with zero_page, whatever is better for particular architecture.
|
|
* Linus?
|
|
*/
|
|
static inline int all_zeroes(__le32 *p, __le32 *q)
|
|
{
|
|
while (p < q)
|
|
if (*p++)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* ext4_find_shared - find the indirect blocks for partial truncation.
|
|
* @inode: inode in question
|
|
* @depth: depth of the affected branch
|
|
* @offsets: offsets of pointers in that branch (see ext4_block_to_path)
|
|
* @chain: place to store the pointers to partial indirect blocks
|
|
* @top: place to the (detached) top of branch
|
|
*
|
|
* This is a helper function used by ext4_truncate().
|
|
*
|
|
* When we do truncate() we may have to clean the ends of several
|
|
* indirect blocks but leave the blocks themselves alive. Block is
|
|
* partially truncated if some data below the new i_size is refered
|
|
* from it (and it is on the path to the first completely truncated
|
|
* data block, indeed). We have to free the top of that path along
|
|
* with everything to the right of the path. Since no allocation
|
|
* past the truncation point is possible until ext4_truncate()
|
|
* finishes, we may safely do the latter, but top of branch may
|
|
* require special attention - pageout below the truncation point
|
|
* might try to populate it.
|
|
*
|
|
* We atomically detach the top of branch from the tree, store the
|
|
* block number of its root in *@top, pointers to buffer_heads of
|
|
* partially truncated blocks - in @chain[].bh and pointers to
|
|
* their last elements that should not be removed - in
|
|
* @chain[].p. Return value is the pointer to last filled element
|
|
* of @chain.
|
|
*
|
|
* The work left to caller to do the actual freeing of subtrees:
|
|
* a) free the subtree starting from *@top
|
|
* b) free the subtrees whose roots are stored in
|
|
* (@chain[i].p+1 .. end of @chain[i].bh->b_data)
|
|
* c) free the subtrees growing from the inode past the @chain[0].
|
|
* (no partially truncated stuff there). */
|
|
|
|
static Indirect *ext4_find_shared(struct inode *inode, int depth,
|
|
ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
|
|
{
|
|
Indirect *partial, *p;
|
|
int k, err;
|
|
|
|
*top = 0;
|
|
/* Make k index the deepest non-null offest + 1 */
|
|
for (k = depth; k > 1 && !offsets[k-1]; k--)
|
|
;
|
|
partial = ext4_get_branch(inode, k, offsets, chain, &err);
|
|
/* Writer: pointers */
|
|
if (!partial)
|
|
partial = chain + k-1;
|
|
/*
|
|
* If the branch acquired continuation since we've looked at it -
|
|
* fine, it should all survive and (new) top doesn't belong to us.
|
|
*/
|
|
if (!partial->key && *partial->p)
|
|
/* Writer: end */
|
|
goto no_top;
|
|
for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
|
|
;
|
|
/*
|
|
* OK, we've found the last block that must survive. The rest of our
|
|
* branch should be detached before unlocking. However, if that rest
|
|
* of branch is all ours and does not grow immediately from the inode
|
|
* it's easier to cheat and just decrement partial->p.
|
|
*/
|
|
if (p == chain + k - 1 && p > chain) {
|
|
p->p--;
|
|
} else {
|
|
*top = *p->p;
|
|
/* Nope, don't do this in ext4. Must leave the tree intact */
|
|
#if 0
|
|
*p->p = 0;
|
|
#endif
|
|
}
|
|
/* Writer: end */
|
|
|
|
while (partial > p) {
|
|
brelse(partial->bh);
|
|
partial--;
|
|
}
|
|
no_top:
|
|
return partial;
|
|
}
|
|
|
|
/*
|
|
* Zero a number of block pointers in either an inode or an indirect block.
|
|
* If we restart the transaction we must again get write access to the
|
|
* indirect block for further modification.
|
|
*
|
|
* We release `count' blocks on disk, but (last - first) may be greater
|
|
* than `count' because there can be holes in there.
|
|
*/
|
|
static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *bh, ext4_fsblk_t block_to_free,
|
|
unsigned long count, __le32 *first, __le32 *last)
|
|
{
|
|
__le32 *p;
|
|
if (try_to_extend_transaction(handle, inode)) {
|
|
if (bh) {
|
|
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
|
ext4_handle_dirty_metadata(handle, inode, bh);
|
|
}
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
ext4_journal_test_restart(handle, inode);
|
|
if (bh) {
|
|
BUFFER_TRACE(bh, "retaking write access");
|
|
ext4_journal_get_write_access(handle, bh);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Any buffers which are on the journal will be in memory. We find
|
|
* them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
|
|
* on them. We've already detached each block from the file, so
|
|
* bforget() in jbd2_journal_forget() should be safe.
|
|
*
|
|
* AKPM: turn on bforget in jbd2_journal_forget()!!!
|
|
*/
|
|
for (p = first; p < last; p++) {
|
|
u32 nr = le32_to_cpu(*p);
|
|
if (nr) {
|
|
struct buffer_head *tbh;
|
|
|
|
*p = 0;
|
|
tbh = sb_find_get_block(inode->i_sb, nr);
|
|
ext4_forget(handle, 0, inode, tbh, nr);
|
|
}
|
|
}
|
|
|
|
ext4_free_blocks(handle, inode, block_to_free, count, 0);
|
|
}
|
|
|
|
/**
|
|
* ext4_free_data - free a list of data blocks
|
|
* @handle: handle for this transaction
|
|
* @inode: inode we are dealing with
|
|
* @this_bh: indirect buffer_head which contains *@first and *@last
|
|
* @first: array of block numbers
|
|
* @last: points immediately past the end of array
|
|
*
|
|
* We are freeing all blocks refered from that array (numbers are stored as
|
|
* little-endian 32-bit) and updating @inode->i_blocks appropriately.
|
|
*
|
|
* We accumulate contiguous runs of blocks to free. Conveniently, if these
|
|
* blocks are contiguous then releasing them at one time will only affect one
|
|
* or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
|
|
* actually use a lot of journal space.
|
|
*
|
|
* @this_bh will be %NULL if @first and @last point into the inode's direct
|
|
* block pointers.
|
|
*/
|
|
static void ext4_free_data(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *this_bh,
|
|
__le32 *first, __le32 *last)
|
|
{
|
|
ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
|
|
unsigned long count = 0; /* Number of blocks in the run */
|
|
__le32 *block_to_free_p = NULL; /* Pointer into inode/ind
|
|
corresponding to
|
|
block_to_free */
|
|
ext4_fsblk_t nr; /* Current block # */
|
|
__le32 *p; /* Pointer into inode/ind
|
|
for current block */
|
|
int err;
|
|
|
|
if (this_bh) { /* For indirect block */
|
|
BUFFER_TRACE(this_bh, "get_write_access");
|
|
err = ext4_journal_get_write_access(handle, this_bh);
|
|
/* Important: if we can't update the indirect pointers
|
|
* to the blocks, we can't free them. */
|
|
if (err)
|
|
return;
|
|
}
|
|
|
|
for (p = first; p < last; p++) {
|
|
nr = le32_to_cpu(*p);
|
|
if (nr) {
|
|
/* accumulate blocks to free if they're contiguous */
|
|
if (count == 0) {
|
|
block_to_free = nr;
|
|
block_to_free_p = p;
|
|
count = 1;
|
|
} else if (nr == block_to_free + count) {
|
|
count++;
|
|
} else {
|
|
ext4_clear_blocks(handle, inode, this_bh,
|
|
block_to_free,
|
|
count, block_to_free_p, p);
|
|
block_to_free = nr;
|
|
block_to_free_p = p;
|
|
count = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (count > 0)
|
|
ext4_clear_blocks(handle, inode, this_bh, block_to_free,
|
|
count, block_to_free_p, p);
|
|
|
|
if (this_bh) {
|
|
BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
|
|
|
|
/*
|
|
* The buffer head should have an attached journal head at this
|
|
* point. However, if the data is corrupted and an indirect
|
|
* block pointed to itself, it would have been detached when
|
|
* the block was cleared. Check for this instead of OOPSing.
|
|
*/
|
|
if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
|
|
ext4_handle_dirty_metadata(handle, inode, this_bh);
|
|
else
|
|
ext4_error(inode->i_sb, __func__,
|
|
"circular indirect block detected, "
|
|
"inode=%lu, block=%llu",
|
|
inode->i_ino,
|
|
(unsigned long long) this_bh->b_blocknr);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* ext4_free_branches - free an array of branches
|
|
* @handle: JBD handle for this transaction
|
|
* @inode: inode we are dealing with
|
|
* @parent_bh: the buffer_head which contains *@first and *@last
|
|
* @first: array of block numbers
|
|
* @last: pointer immediately past the end of array
|
|
* @depth: depth of the branches to free
|
|
*
|
|
* We are freeing all blocks refered from these branches (numbers are
|
|
* stored as little-endian 32-bit) and updating @inode->i_blocks
|
|
* appropriately.
|
|
*/
|
|
static void ext4_free_branches(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *parent_bh,
|
|
__le32 *first, __le32 *last, int depth)
|
|
{
|
|
ext4_fsblk_t nr;
|
|
__le32 *p;
|
|
|
|
if (ext4_handle_is_aborted(handle))
|
|
return;
|
|
|
|
if (depth--) {
|
|
struct buffer_head *bh;
|
|
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
p = last;
|
|
while (--p >= first) {
|
|
nr = le32_to_cpu(*p);
|
|
if (!nr)
|
|
continue; /* A hole */
|
|
|
|
/* Go read the buffer for the next level down */
|
|
bh = sb_bread(inode->i_sb, nr);
|
|
|
|
/*
|
|
* A read failure? Report error and clear slot
|
|
* (should be rare).
|
|
*/
|
|
if (!bh) {
|
|
ext4_error(inode->i_sb, "ext4_free_branches",
|
|
"Read failure, inode=%lu, block=%llu",
|
|
inode->i_ino, nr);
|
|
continue;
|
|
}
|
|
|
|
/* This zaps the entire block. Bottom up. */
|
|
BUFFER_TRACE(bh, "free child branches");
|
|
ext4_free_branches(handle, inode, bh,
|
|
(__le32 *) bh->b_data,
|
|
(__le32 *) bh->b_data + addr_per_block,
|
|
depth);
|
|
|
|
/*
|
|
* We've probably journalled the indirect block several
|
|
* times during the truncate. But it's no longer
|
|
* needed and we now drop it from the transaction via
|
|
* jbd2_journal_revoke().
|
|
*
|
|
* That's easy if it's exclusively part of this
|
|
* transaction. But if it's part of the committing
|
|
* transaction then jbd2_journal_forget() will simply
|
|
* brelse() it. That means that if the underlying
|
|
* block is reallocated in ext4_get_block(),
|
|
* unmap_underlying_metadata() will find this block
|
|
* and will try to get rid of it. damn, damn.
|
|
*
|
|
* If this block has already been committed to the
|
|
* journal, a revoke record will be written. And
|
|
* revoke records must be emitted *before* clearing
|
|
* this block's bit in the bitmaps.
|
|
*/
|
|
ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
|
|
|
|
/*
|
|
* Everything below this this pointer has been
|
|
* released. Now let this top-of-subtree go.
|
|
*
|
|
* We want the freeing of this indirect block to be
|
|
* atomic in the journal with the updating of the
|
|
* bitmap block which owns it. So make some room in
|
|
* the journal.
|
|
*
|
|
* We zero the parent pointer *after* freeing its
|
|
* pointee in the bitmaps, so if extend_transaction()
|
|
* for some reason fails to put the bitmap changes and
|
|
* the release into the same transaction, recovery
|
|
* will merely complain about releasing a free block,
|
|
* rather than leaking blocks.
|
|
*/
|
|
if (ext4_handle_is_aborted(handle))
|
|
return;
|
|
if (try_to_extend_transaction(handle, inode)) {
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
ext4_journal_test_restart(handle, inode);
|
|
}
|
|
|
|
ext4_free_blocks(handle, inode, nr, 1, 1);
|
|
|
|
if (parent_bh) {
|
|
/*
|
|
* The block which we have just freed is
|
|
* pointed to by an indirect block: journal it
|
|
*/
|
|
BUFFER_TRACE(parent_bh, "get_write_access");
|
|
if (!ext4_journal_get_write_access(handle,
|
|
parent_bh)){
|
|
*p = 0;
|
|
BUFFER_TRACE(parent_bh,
|
|
"call ext4_handle_dirty_metadata");
|
|
ext4_handle_dirty_metadata(handle,
|
|
inode,
|
|
parent_bh);
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
/* We have reached the bottom of the tree. */
|
|
BUFFER_TRACE(parent_bh, "free data blocks");
|
|
ext4_free_data(handle, inode, parent_bh, first, last);
|
|
}
|
|
}
|
|
|
|
int ext4_can_truncate(struct inode *inode)
|
|
{
|
|
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
|
|
return 0;
|
|
if (S_ISREG(inode->i_mode))
|
|
return 1;
|
|
if (S_ISDIR(inode->i_mode))
|
|
return 1;
|
|
if (S_ISLNK(inode->i_mode))
|
|
return !ext4_inode_is_fast_symlink(inode);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* ext4_truncate()
|
|
*
|
|
* We block out ext4_get_block() block instantiations across the entire
|
|
* transaction, and VFS/VM ensures that ext4_truncate() cannot run
|
|
* simultaneously on behalf of the same inode.
|
|
*
|
|
* As we work through the truncate and commmit bits of it to the journal there
|
|
* is one core, guiding principle: the file's tree must always be consistent on
|
|
* disk. We must be able to restart the truncate after a crash.
|
|
*
|
|
* The file's tree may be transiently inconsistent in memory (although it
|
|
* probably isn't), but whenever we close off and commit a journal transaction,
|
|
* the contents of (the filesystem + the journal) must be consistent and
|
|
* restartable. It's pretty simple, really: bottom up, right to left (although
|
|
* left-to-right works OK too).
|
|
*
|
|
* Note that at recovery time, journal replay occurs *before* the restart of
|
|
* truncate against the orphan inode list.
|
|
*
|
|
* The committed inode has the new, desired i_size (which is the same as
|
|
* i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
|
|
* that this inode's truncate did not complete and it will again call
|
|
* ext4_truncate() to have another go. So there will be instantiated blocks
|
|
* to the right of the truncation point in a crashed ext4 filesystem. But
|
|
* that's fine - as long as they are linked from the inode, the post-crash
|
|
* ext4_truncate() run will find them and release them.
|
|
*/
|
|
void ext4_truncate(struct inode *inode)
|
|
{
|
|
handle_t *handle;
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
__le32 *i_data = ei->i_data;
|
|
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
struct address_space *mapping = inode->i_mapping;
|
|
ext4_lblk_t offsets[4];
|
|
Indirect chain[4];
|
|
Indirect *partial;
|
|
__le32 nr = 0;
|
|
int n;
|
|
ext4_lblk_t last_block;
|
|
unsigned blocksize = inode->i_sb->s_blocksize;
|
|
|
|
if (!ext4_can_truncate(inode))
|
|
return;
|
|
|
|
if (ei->i_disksize && inode->i_size == 0 &&
|
|
!test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
|
|
ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
|
|
|
|
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
|
|
ext4_ext_truncate(inode);
|
|
return;
|
|
}
|
|
|
|
handle = start_transaction(inode);
|
|
if (IS_ERR(handle))
|
|
return; /* AKPM: return what? */
|
|
|
|
last_block = (inode->i_size + blocksize-1)
|
|
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
|
|
|
if (inode->i_size & (blocksize - 1))
|
|
if (ext4_block_truncate_page(handle, mapping, inode->i_size))
|
|
goto out_stop;
|
|
|
|
n = ext4_block_to_path(inode, last_block, offsets, NULL);
|
|
if (n == 0)
|
|
goto out_stop; /* error */
|
|
|
|
/*
|
|
* OK. This truncate is going to happen. We add the inode to the
|
|
* orphan list, so that if this truncate spans multiple transactions,
|
|
* and we crash, we will resume the truncate when the filesystem
|
|
* recovers. It also marks the inode dirty, to catch the new size.
|
|
*
|
|
* Implication: the file must always be in a sane, consistent
|
|
* truncatable state while each transaction commits.
|
|
*/
|
|
if (ext4_orphan_add(handle, inode))
|
|
goto out_stop;
|
|
|
|
/*
|
|
* From here we block out all ext4_get_block() callers who want to
|
|
* modify the block allocation tree.
|
|
*/
|
|
down_write(&ei->i_data_sem);
|
|
|
|
ext4_discard_preallocations(inode);
|
|
|
|
/*
|
|
* The orphan list entry will now protect us from any crash which
|
|
* occurs before the truncate completes, so it is now safe to propagate
|
|
* the new, shorter inode size (held for now in i_size) into the
|
|
* on-disk inode. We do this via i_disksize, which is the value which
|
|
* ext4 *really* writes onto the disk inode.
|
|
*/
|
|
ei->i_disksize = inode->i_size;
|
|
|
|
if (n == 1) { /* direct blocks */
|
|
ext4_free_data(handle, inode, NULL, i_data+offsets[0],
|
|
i_data + EXT4_NDIR_BLOCKS);
|
|
goto do_indirects;
|
|
}
|
|
|
|
partial = ext4_find_shared(inode, n, offsets, chain, &nr);
|
|
/* Kill the top of shared branch (not detached) */
|
|
if (nr) {
|
|
if (partial == chain) {
|
|
/* Shared branch grows from the inode */
|
|
ext4_free_branches(handle, inode, NULL,
|
|
&nr, &nr+1, (chain+n-1) - partial);
|
|
*partial->p = 0;
|
|
/*
|
|
* We mark the inode dirty prior to restart,
|
|
* and prior to stop. No need for it here.
|
|
*/
|
|
} else {
|
|
/* Shared branch grows from an indirect block */
|
|
BUFFER_TRACE(partial->bh, "get_write_access");
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p,
|
|
partial->p+1, (chain+n-1) - partial);
|
|
}
|
|
}
|
|
/* Clear the ends of indirect blocks on the shared branch */
|
|
while (partial > chain) {
|
|
ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
|
|
(__le32*)partial->bh->b_data+addr_per_block,
|
|
(chain+n-1) - partial);
|
|
BUFFER_TRACE(partial->bh, "call brelse");
|
|
brelse (partial->bh);
|
|
partial--;
|
|
}
|
|
do_indirects:
|
|
/* Kill the remaining (whole) subtrees */
|
|
switch (offsets[0]) {
|
|
default:
|
|
nr = i_data[EXT4_IND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
|
|
i_data[EXT4_IND_BLOCK] = 0;
|
|
}
|
|
case EXT4_IND_BLOCK:
|
|
nr = i_data[EXT4_DIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
|
|
i_data[EXT4_DIND_BLOCK] = 0;
|
|
}
|
|
case EXT4_DIND_BLOCK:
|
|
nr = i_data[EXT4_TIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
|
|
i_data[EXT4_TIND_BLOCK] = 0;
|
|
}
|
|
case EXT4_TIND_BLOCK:
|
|
;
|
|
}
|
|
|
|
up_write(&ei->i_data_sem);
|
|
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
|
|
/*
|
|
* In a multi-transaction truncate, we only make the final transaction
|
|
* synchronous
|
|
*/
|
|
if (IS_SYNC(inode))
|
|
ext4_handle_sync(handle);
|
|
out_stop:
|
|
/*
|
|
* If this was a simple ftruncate(), and the file will remain alive
|
|
* then we need to clear up the orphan record which we created above.
|
|
* However, if this was a real unlink then we were called by
|
|
* ext4_delete_inode(), and we allow that function to clean up the
|
|
* orphan info for us.
|
|
*/
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(handle, inode);
|
|
|
|
ext4_journal_stop(handle);
|
|
}
|
|
|
|
/*
|
|
* ext4_get_inode_loc returns with an extra refcount against the inode's
|
|
* underlying buffer_head on success. If 'in_mem' is true, we have all
|
|
* data in memory that is needed to recreate the on-disk version of this
|
|
* inode.
|
|
*/
|
|
static int __ext4_get_inode_loc(struct inode *inode,
|
|
struct ext4_iloc *iloc, int in_mem)
|
|
{
|
|
struct ext4_group_desc *gdp;
|
|
struct buffer_head *bh;
|
|
struct super_block *sb = inode->i_sb;
|
|
ext4_fsblk_t block;
|
|
int inodes_per_block, inode_offset;
|
|
|
|
iloc->bh = NULL;
|
|
if (!ext4_valid_inum(sb, inode->i_ino))
|
|
return -EIO;
|
|
|
|
iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
|
|
gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
|
|
if (!gdp)
|
|
return -EIO;
|
|
|
|
/*
|
|
* Figure out the offset within the block group inode table
|
|
*/
|
|
inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
|
|
inode_offset = ((inode->i_ino - 1) %
|
|
EXT4_INODES_PER_GROUP(sb));
|
|
block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
|
|
iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
|
|
|
|
bh = sb_getblk(sb, block);
|
|
if (!bh) {
|
|
ext4_error(sb, "ext4_get_inode_loc", "unable to read "
|
|
"inode block - inode=%lu, block=%llu",
|
|
inode->i_ino, block);
|
|
return -EIO;
|
|
}
|
|
if (!buffer_uptodate(bh)) {
|
|
lock_buffer(bh);
|
|
|
|
/*
|
|
* If the buffer has the write error flag, we have failed
|
|
* to write out another inode in the same block. In this
|
|
* case, we don't have to read the block because we may
|
|
* read the old inode data successfully.
|
|
*/
|
|
if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
|
|
set_buffer_uptodate(bh);
|
|
|
|
if (buffer_uptodate(bh)) {
|
|
/* someone brought it uptodate while we waited */
|
|
unlock_buffer(bh);
|
|
goto has_buffer;
|
|
}
|
|
|
|
/*
|
|
* If we have all information of the inode in memory and this
|
|
* is the only valid inode in the block, we need not read the
|
|
* block.
|
|
*/
|
|
if (in_mem) {
|
|
struct buffer_head *bitmap_bh;
|
|
int i, start;
|
|
|
|
start = inode_offset & ~(inodes_per_block - 1);
|
|
|
|
/* Is the inode bitmap in cache? */
|
|
bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
|
|
if (!bitmap_bh)
|
|
goto make_io;
|
|
|
|
/*
|
|
* If the inode bitmap isn't in cache then the
|
|
* optimisation may end up performing two reads instead
|
|
* of one, so skip it.
|
|
*/
|
|
if (!buffer_uptodate(bitmap_bh)) {
|
|
brelse(bitmap_bh);
|
|
goto make_io;
|
|
}
|
|
for (i = start; i < start + inodes_per_block; i++) {
|
|
if (i == inode_offset)
|
|
continue;
|
|
if (ext4_test_bit(i, bitmap_bh->b_data))
|
|
break;
|
|
}
|
|
brelse(bitmap_bh);
|
|
if (i == start + inodes_per_block) {
|
|
/* all other inodes are free, so skip I/O */
|
|
memset(bh->b_data, 0, bh->b_size);
|
|
set_buffer_uptodate(bh);
|
|
unlock_buffer(bh);
|
|
goto has_buffer;
|
|
}
|
|
}
|
|
|
|
make_io:
|
|
/*
|
|
* If we need to do any I/O, try to pre-readahead extra
|
|
* blocks from the inode table.
|
|
*/
|
|
if (EXT4_SB(sb)->s_inode_readahead_blks) {
|
|
ext4_fsblk_t b, end, table;
|
|
unsigned num;
|
|
|
|
table = ext4_inode_table(sb, gdp);
|
|
/* s_inode_readahead_blks is always a power of 2 */
|
|
b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
|
|
if (table > b)
|
|
b = table;
|
|
end = b + EXT4_SB(sb)->s_inode_readahead_blks;
|
|
num = EXT4_INODES_PER_GROUP(sb);
|
|
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
|
|
EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
|
|
num -= ext4_itable_unused_count(sb, gdp);
|
|
table += num / inodes_per_block;
|
|
if (end > table)
|
|
end = table;
|
|
while (b <= end)
|
|
sb_breadahead(sb, b++);
|
|
}
|
|
|
|
/*
|
|
* There are other valid inodes in the buffer, this inode
|
|
* has in-inode xattrs, or we don't have this inode in memory.
|
|
* Read the block from disk.
|
|
*/
|
|
get_bh(bh);
|
|
bh->b_end_io = end_buffer_read_sync;
|
|
submit_bh(READ_META, bh);
|
|
wait_on_buffer(bh);
|
|
if (!buffer_uptodate(bh)) {
|
|
ext4_error(sb, __func__,
|
|
"unable to read inode block - inode=%lu, "
|
|
"block=%llu", inode->i_ino, block);
|
|
brelse(bh);
|
|
return -EIO;
|
|
}
|
|
}
|
|
has_buffer:
|
|
iloc->bh = bh;
|
|
return 0;
|
|
}
|
|
|
|
int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
|
|
{
|
|
/* We have all inode data except xattrs in memory here. */
|
|
return __ext4_get_inode_loc(inode, iloc,
|
|
!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
|
|
}
|
|
|
|
void ext4_set_inode_flags(struct inode *inode)
|
|
{
|
|
unsigned int flags = EXT4_I(inode)->i_flags;
|
|
|
|
inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
|
|
if (flags & EXT4_SYNC_FL)
|
|
inode->i_flags |= S_SYNC;
|
|
if (flags & EXT4_APPEND_FL)
|
|
inode->i_flags |= S_APPEND;
|
|
if (flags & EXT4_IMMUTABLE_FL)
|
|
inode->i_flags |= S_IMMUTABLE;
|
|
if (flags & EXT4_NOATIME_FL)
|
|
inode->i_flags |= S_NOATIME;
|
|
if (flags & EXT4_DIRSYNC_FL)
|
|
inode->i_flags |= S_DIRSYNC;
|
|
}
|
|
|
|
/* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
|
|
void ext4_get_inode_flags(struct ext4_inode_info *ei)
|
|
{
|
|
unsigned int flags = ei->vfs_inode.i_flags;
|
|
|
|
ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
|
|
EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
|
|
if (flags & S_SYNC)
|
|
ei->i_flags |= EXT4_SYNC_FL;
|
|
if (flags & S_APPEND)
|
|
ei->i_flags |= EXT4_APPEND_FL;
|
|
if (flags & S_IMMUTABLE)
|
|
ei->i_flags |= EXT4_IMMUTABLE_FL;
|
|
if (flags & S_NOATIME)
|
|
ei->i_flags |= EXT4_NOATIME_FL;
|
|
if (flags & S_DIRSYNC)
|
|
ei->i_flags |= EXT4_DIRSYNC_FL;
|
|
}
|
|
static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
|
|
struct ext4_inode_info *ei)
|
|
{
|
|
blkcnt_t i_blocks ;
|
|
struct inode *inode = &(ei->vfs_inode);
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
|
|
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
|
|
/* we are using combined 48 bit field */
|
|
i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
|
|
le32_to_cpu(raw_inode->i_blocks_lo);
|
|
if (ei->i_flags & EXT4_HUGE_FILE_FL) {
|
|
/* i_blocks represent file system block size */
|
|
return i_blocks << (inode->i_blkbits - 9);
|
|
} else {
|
|
return i_blocks;
|
|
}
|
|
} else {
|
|
return le32_to_cpu(raw_inode->i_blocks_lo);
|
|
}
|
|
}
|
|
|
|
struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct ext4_iloc iloc;
|
|
struct ext4_inode *raw_inode;
|
|
struct ext4_inode_info *ei;
|
|
struct buffer_head *bh;
|
|
struct inode *inode;
|
|
long ret;
|
|
int block;
|
|
|
|
inode = iget_locked(sb, ino);
|
|
if (!inode)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (!(inode->i_state & I_NEW))
|
|
return inode;
|
|
|
|
ei = EXT4_I(inode);
|
|
#ifdef CONFIG_EXT4_FS_POSIX_ACL
|
|
ei->i_acl = EXT4_ACL_NOT_CACHED;
|
|
ei->i_default_acl = EXT4_ACL_NOT_CACHED;
|
|
#endif
|
|
|
|
ret = __ext4_get_inode_loc(inode, &iloc, 0);
|
|
if (ret < 0)
|
|
goto bad_inode;
|
|
bh = iloc.bh;
|
|
raw_inode = ext4_raw_inode(&iloc);
|
|
inode->i_mode = le16_to_cpu(raw_inode->i_mode);
|
|
inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
|
|
inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
|
|
if (!(test_opt(inode->i_sb, NO_UID32))) {
|
|
inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
|
|
inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
|
|
}
|
|
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
|
|
|
|
ei->i_state = 0;
|
|
ei->i_dir_start_lookup = 0;
|
|
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
|
|
/* We now have enough fields to check if the inode was active or not.
|
|
* This is needed because nfsd might try to access dead inodes
|
|
* the test is that same one that e2fsck uses
|
|
* NeilBrown 1999oct15
|
|
*/
|
|
if (inode->i_nlink == 0) {
|
|
if (inode->i_mode == 0 ||
|
|
!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
|
|
/* this inode is deleted */
|
|
brelse(bh);
|
|
ret = -ESTALE;
|
|
goto bad_inode;
|
|
}
|
|
/* The only unlinked inodes we let through here have
|
|
* valid i_mode and are being read by the orphan
|
|
* recovery code: that's fine, we're about to complete
|
|
* the process of deleting those. */
|
|
}
|
|
ei->i_flags = le32_to_cpu(raw_inode->i_flags);
|
|
inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
|
|
ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
|
|
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
|
|
ei->i_file_acl |=
|
|
((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
|
|
inode->i_size = ext4_isize(raw_inode);
|
|
ei->i_disksize = inode->i_size;
|
|
inode->i_generation = le32_to_cpu(raw_inode->i_generation);
|
|
ei->i_block_group = iloc.block_group;
|
|
ei->i_last_alloc_group = ~0;
|
|
/*
|
|
* NOTE! The in-memory inode i_data array is in little-endian order
|
|
* even on big-endian machines: we do NOT byteswap the block numbers!
|
|
*/
|
|
for (block = 0; block < EXT4_N_BLOCKS; block++)
|
|
ei->i_data[block] = raw_inode->i_block[block];
|
|
INIT_LIST_HEAD(&ei->i_orphan);
|
|
|
|
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
|
|
ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
|
|
if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
|
|
EXT4_INODE_SIZE(inode->i_sb)) {
|
|
brelse(bh);
|
|
ret = -EIO;
|
|
goto bad_inode;
|
|
}
|
|
if (ei->i_extra_isize == 0) {
|
|
/* The extra space is currently unused. Use it. */
|
|
ei->i_extra_isize = sizeof(struct ext4_inode) -
|
|
EXT4_GOOD_OLD_INODE_SIZE;
|
|
} else {
|
|
__le32 *magic = (void *)raw_inode +
|
|
EXT4_GOOD_OLD_INODE_SIZE +
|
|
ei->i_extra_isize;
|
|
if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
|
|
ei->i_state |= EXT4_STATE_XATTR;
|
|
}
|
|
} else
|
|
ei->i_extra_isize = 0;
|
|
|
|
EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
|
|
EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
|
|
EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
|
|
EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
|
|
|
|
inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
|
|
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
|
|
if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
|
|
inode->i_version |=
|
|
(__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
|
|
}
|
|
|
|
ret = 0;
|
|
if (ei->i_file_acl &&
|
|
((ei->i_file_acl <
|
|
(le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
|
|
EXT4_SB(sb)->s_gdb_count)) ||
|
|
(ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
|
|
ext4_error(sb, __func__,
|
|
"bad extended attribute block %llu in inode #%lu",
|
|
ei->i_file_acl, inode->i_ino);
|
|
ret = -EIO;
|
|
goto bad_inode;
|
|
} else if (ei->i_flags & EXT4_EXTENTS_FL) {
|
|
if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
|
|
(S_ISLNK(inode->i_mode) &&
|
|
!ext4_inode_is_fast_symlink(inode)))
|
|
/* Validate extent which is part of inode */
|
|
ret = ext4_ext_check_inode(inode);
|
|
} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
|
|
(S_ISLNK(inode->i_mode) &&
|
|
!ext4_inode_is_fast_symlink(inode))) {
|
|
/* Validate block references which are part of inode */
|
|
ret = ext4_check_inode_blockref(inode);
|
|
}
|
|
if (ret) {
|
|
brelse(bh);
|
|
goto bad_inode;
|
|
}
|
|
|
|
if (S_ISREG(inode->i_mode)) {
|
|
inode->i_op = &ext4_file_inode_operations;
|
|
inode->i_fop = &ext4_file_operations;
|
|
ext4_set_aops(inode);
|
|
} else if (S_ISDIR(inode->i_mode)) {
|
|
inode->i_op = &ext4_dir_inode_operations;
|
|
inode->i_fop = &ext4_dir_operations;
|
|
} else if (S_ISLNK(inode->i_mode)) {
|
|
if (ext4_inode_is_fast_symlink(inode)) {
|
|
inode->i_op = &ext4_fast_symlink_inode_operations;
|
|
nd_terminate_link(ei->i_data, inode->i_size,
|
|
sizeof(ei->i_data) - 1);
|
|
} else {
|
|
inode->i_op = &ext4_symlink_inode_operations;
|
|
ext4_set_aops(inode);
|
|
}
|
|
} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
|
|
S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
|
|
inode->i_op = &ext4_special_inode_operations;
|
|
if (raw_inode->i_block[0])
|
|
init_special_inode(inode, inode->i_mode,
|
|
old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
|
|
else
|
|
init_special_inode(inode, inode->i_mode,
|
|
new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
|
|
} else {
|
|
brelse(bh);
|
|
ret = -EIO;
|
|
ext4_error(inode->i_sb, __func__,
|
|
"bogus i_mode (%o) for inode=%lu",
|
|
inode->i_mode, inode->i_ino);
|
|
goto bad_inode;
|
|
}
|
|
brelse(iloc.bh);
|
|
ext4_set_inode_flags(inode);
|
|
unlock_new_inode(inode);
|
|
return inode;
|
|
|
|
bad_inode:
|
|
iget_failed(inode);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
static int ext4_inode_blocks_set(handle_t *handle,
|
|
struct ext4_inode *raw_inode,
|
|
struct ext4_inode_info *ei)
|
|
{
|
|
struct inode *inode = &(ei->vfs_inode);
|
|
u64 i_blocks = inode->i_blocks;
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
if (i_blocks <= ~0U) {
|
|
/*
|
|
* i_blocks can be represnted in a 32 bit variable
|
|
* as multiple of 512 bytes
|
|
*/
|
|
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
|
|
raw_inode->i_blocks_high = 0;
|
|
ei->i_flags &= ~EXT4_HUGE_FILE_FL;
|
|
return 0;
|
|
}
|
|
if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
|
|
return -EFBIG;
|
|
|
|
if (i_blocks <= 0xffffffffffffULL) {
|
|
/*
|
|
* i_blocks can be represented in a 48 bit variable
|
|
* as multiple of 512 bytes
|
|
*/
|
|
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
|
|
raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
|
|
ei->i_flags &= ~EXT4_HUGE_FILE_FL;
|
|
} else {
|
|
ei->i_flags |= EXT4_HUGE_FILE_FL;
|
|
/* i_block is stored in file system block size */
|
|
i_blocks = i_blocks >> (inode->i_blkbits - 9);
|
|
raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
|
|
raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Post the struct inode info into an on-disk inode location in the
|
|
* buffer-cache. This gobbles the caller's reference to the
|
|
* buffer_head in the inode location struct.
|
|
*
|
|
* The caller must have write access to iloc->bh.
|
|
*/
|
|
static int ext4_do_update_inode(handle_t *handle,
|
|
struct inode *inode,
|
|
struct ext4_iloc *iloc)
|
|
{
|
|
struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
struct buffer_head *bh = iloc->bh;
|
|
int err = 0, rc, block;
|
|
|
|
/* For fields not not tracking in the in-memory inode,
|
|
* initialise them to zero for new inodes. */
|
|
if (ei->i_state & EXT4_STATE_NEW)
|
|
memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
|
|
|
|
ext4_get_inode_flags(ei);
|
|
raw_inode->i_mode = cpu_to_le16(inode->i_mode);
|
|
if (!(test_opt(inode->i_sb, NO_UID32))) {
|
|
raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
|
|
raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
|
|
/*
|
|
* Fix up interoperability with old kernels. Otherwise, old inodes get
|
|
* re-used with the upper 16 bits of the uid/gid intact
|
|
*/
|
|
if (!ei->i_dtime) {
|
|
raw_inode->i_uid_high =
|
|
cpu_to_le16(high_16_bits(inode->i_uid));
|
|
raw_inode->i_gid_high =
|
|
cpu_to_le16(high_16_bits(inode->i_gid));
|
|
} else {
|
|
raw_inode->i_uid_high = 0;
|
|
raw_inode->i_gid_high = 0;
|
|
}
|
|
} else {
|
|
raw_inode->i_uid_low =
|
|
cpu_to_le16(fs_high2lowuid(inode->i_uid));
|
|
raw_inode->i_gid_low =
|
|
cpu_to_le16(fs_high2lowgid(inode->i_gid));
|
|
raw_inode->i_uid_high = 0;
|
|
raw_inode->i_gid_high = 0;
|
|
}
|
|
raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
|
|
|
|
EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
|
|
EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
|
|
EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
|
|
EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
|
|
|
|
if (ext4_inode_blocks_set(handle, raw_inode, ei))
|
|
goto out_brelse;
|
|
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
|
|
/* clear the migrate flag in the raw_inode */
|
|
raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
|
|
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
|
|
cpu_to_le32(EXT4_OS_HURD))
|
|
raw_inode->i_file_acl_high =
|
|
cpu_to_le16(ei->i_file_acl >> 32);
|
|
raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
|
|
ext4_isize_set(raw_inode, ei->i_disksize);
|
|
if (ei->i_disksize > 0x7fffffffULL) {
|
|
struct super_block *sb = inode->i_sb;
|
|
if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
|
|
EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
|
|
EXT4_SB(sb)->s_es->s_rev_level ==
|
|
cpu_to_le32(EXT4_GOOD_OLD_REV)) {
|
|
/* If this is the first large file
|
|
* created, add a flag to the superblock.
|
|
*/
|
|
err = ext4_journal_get_write_access(handle,
|
|
EXT4_SB(sb)->s_sbh);
|
|
if (err)
|
|
goto out_brelse;
|
|
ext4_update_dynamic_rev(sb);
|
|
EXT4_SET_RO_COMPAT_FEATURE(sb,
|
|
EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
|
|
sb->s_dirt = 1;
|
|
ext4_handle_sync(handle);
|
|
err = ext4_handle_dirty_metadata(handle, inode,
|
|
EXT4_SB(sb)->s_sbh);
|
|
}
|
|
}
|
|
raw_inode->i_generation = cpu_to_le32(inode->i_generation);
|
|
if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
|
|
if (old_valid_dev(inode->i_rdev)) {
|
|
raw_inode->i_block[0] =
|
|
cpu_to_le32(old_encode_dev(inode->i_rdev));
|
|
raw_inode->i_block[1] = 0;
|
|
} else {
|
|
raw_inode->i_block[0] = 0;
|
|
raw_inode->i_block[1] =
|
|
cpu_to_le32(new_encode_dev(inode->i_rdev));
|
|
raw_inode->i_block[2] = 0;
|
|
}
|
|
} else for (block = 0; block < EXT4_N_BLOCKS; block++)
|
|
raw_inode->i_block[block] = ei->i_data[block];
|
|
|
|
raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
|
|
if (ei->i_extra_isize) {
|
|
if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
|
|
raw_inode->i_version_hi =
|
|
cpu_to_le32(inode->i_version >> 32);
|
|
raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
|
|
}
|
|
|
|
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
|
rc = ext4_handle_dirty_metadata(handle, inode, bh);
|
|
if (!err)
|
|
err = rc;
|
|
ei->i_state &= ~EXT4_STATE_NEW;
|
|
|
|
out_brelse:
|
|
brelse(bh);
|
|
ext4_std_error(inode->i_sb, err);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* ext4_write_inode()
|
|
*
|
|
* We are called from a few places:
|
|
*
|
|
* - Within generic_file_write() for O_SYNC files.
|
|
* Here, there will be no transaction running. We wait for any running
|
|
* trasnaction to commit.
|
|
*
|
|
* - Within sys_sync(), kupdate and such.
|
|
* We wait on commit, if tol to.
|
|
*
|
|
* - Within prune_icache() (PF_MEMALLOC == true)
|
|
* Here we simply return. We can't afford to block kswapd on the
|
|
* journal commit.
|
|
*
|
|
* In all cases it is actually safe for us to return without doing anything,
|
|
* because the inode has been copied into a raw inode buffer in
|
|
* ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
|
|
* knfsd.
|
|
*
|
|
* Note that we are absolutely dependent upon all inode dirtiers doing the
|
|
* right thing: they *must* call mark_inode_dirty() after dirtying info in
|
|
* which we are interested.
|
|
*
|
|
* It would be a bug for them to not do this. The code:
|
|
*
|
|
* mark_inode_dirty(inode)
|
|
* stuff();
|
|
* inode->i_size = expr;
|
|
*
|
|
* is in error because a kswapd-driven write_inode() could occur while
|
|
* `stuff()' is running, and the new i_size will be lost. Plus the inode
|
|
* will no longer be on the superblock's dirty inode list.
|
|
*/
|
|
int ext4_write_inode(struct inode *inode, int wait)
|
|
{
|
|
if (current->flags & PF_MEMALLOC)
|
|
return 0;
|
|
|
|
if (ext4_journal_current_handle()) {
|
|
jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
|
|
dump_stack();
|
|
return -EIO;
|
|
}
|
|
|
|
if (!wait)
|
|
return 0;
|
|
|
|
return ext4_force_commit(inode->i_sb);
|
|
}
|
|
|
|
/*
|
|
* ext4_setattr()
|
|
*
|
|
* Called from notify_change.
|
|
*
|
|
* We want to trap VFS attempts to truncate the file as soon as
|
|
* possible. In particular, we want to make sure that when the VFS
|
|
* shrinks i_size, we put the inode on the orphan list and modify
|
|
* i_disksize immediately, so that during the subsequent flushing of
|
|
* dirty pages and freeing of disk blocks, we can guarantee that any
|
|
* commit will leave the blocks being flushed in an unused state on
|
|
* disk. (On recovery, the inode will get truncated and the blocks will
|
|
* be freed, so we have a strong guarantee that no future commit will
|
|
* leave these blocks visible to the user.)
|
|
*
|
|
* Another thing we have to assure is that if we are in ordered mode
|
|
* and inode is still attached to the committing transaction, we must
|
|
* we start writeout of all the dirty pages which are being truncated.
|
|
* This way we are sure that all the data written in the previous
|
|
* transaction are already on disk (truncate waits for pages under
|
|
* writeback).
|
|
*
|
|
* Called with inode->i_mutex down.
|
|
*/
|
|
int ext4_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error, rc = 0;
|
|
const unsigned int ia_valid = attr->ia_valid;
|
|
|
|
error = inode_change_ok(inode, attr);
|
|
if (error)
|
|
return error;
|
|
|
|
if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
|
|
(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
|
|
handle_t *handle;
|
|
|
|
/* (user+group)*(old+new) structure, inode write (sb,
|
|
* inode block, ? - but truncate inode update has it) */
|
|
handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
|
|
EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
|
|
if (IS_ERR(handle)) {
|
|
error = PTR_ERR(handle);
|
|
goto err_out;
|
|
}
|
|
error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
|
|
if (error) {
|
|
ext4_journal_stop(handle);
|
|
return error;
|
|
}
|
|
/* Update corresponding info in inode so that everything is in
|
|
* one transaction */
|
|
if (attr->ia_valid & ATTR_UID)
|
|
inode->i_uid = attr->ia_uid;
|
|
if (attr->ia_valid & ATTR_GID)
|
|
inode->i_gid = attr->ia_gid;
|
|
error = ext4_mark_inode_dirty(handle, inode);
|
|
ext4_journal_stop(handle);
|
|
}
|
|
|
|
if (attr->ia_valid & ATTR_SIZE) {
|
|
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
|
|
if (attr->ia_size > sbi->s_bitmap_maxbytes) {
|
|
error = -EFBIG;
|
|
goto err_out;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (S_ISREG(inode->i_mode) &&
|
|
attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
|
|
handle_t *handle;
|
|
|
|
handle = ext4_journal_start(inode, 3);
|
|
if (IS_ERR(handle)) {
|
|
error = PTR_ERR(handle);
|
|
goto err_out;
|
|
}
|
|
|
|
error = ext4_orphan_add(handle, inode);
|
|
EXT4_I(inode)->i_disksize = attr->ia_size;
|
|
rc = ext4_mark_inode_dirty(handle, inode);
|
|
if (!error)
|
|
error = rc;
|
|
ext4_journal_stop(handle);
|
|
|
|
if (ext4_should_order_data(inode)) {
|
|
error = ext4_begin_ordered_truncate(inode,
|
|
attr->ia_size);
|
|
if (error) {
|
|
/* Do as much error cleanup as possible */
|
|
handle = ext4_journal_start(inode, 3);
|
|
if (IS_ERR(handle)) {
|
|
ext4_orphan_del(NULL, inode);
|
|
goto err_out;
|
|
}
|
|
ext4_orphan_del(handle, inode);
|
|
ext4_journal_stop(handle);
|
|
goto err_out;
|
|
}
|
|
}
|
|
}
|
|
|
|
rc = inode_setattr(inode, attr);
|
|
|
|
/* If inode_setattr's call to ext4_truncate failed to get a
|
|
* transaction handle at all, we need to clean up the in-core
|
|
* orphan list manually. */
|
|
if (inode->i_nlink)
|
|
ext4_orphan_del(NULL, inode);
|
|
|
|
if (!rc && (ia_valid & ATTR_MODE))
|
|
rc = ext4_acl_chmod(inode);
|
|
|
|
err_out:
|
|
ext4_std_error(inode->i_sb, error);
|
|
if (!error)
|
|
error = rc;
|
|
return error;
|
|
}
|
|
|
|
int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
|
|
struct kstat *stat)
|
|
{
|
|
struct inode *inode;
|
|
unsigned long delalloc_blocks;
|
|
|
|
inode = dentry->d_inode;
|
|
generic_fillattr(inode, stat);
|
|
|
|
/*
|
|
* We can't update i_blocks if the block allocation is delayed
|
|
* otherwise in the case of system crash before the real block
|
|
* allocation is done, we will have i_blocks inconsistent with
|
|
* on-disk file blocks.
|
|
* We always keep i_blocks updated together with real
|
|
* allocation. But to not confuse with user, stat
|
|
* will return the blocks that include the delayed allocation
|
|
* blocks for this file.
|
|
*/
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
|
|
stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
|
|
return 0;
|
|
}
|
|
|
|
static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
|
|
int chunk)
|
|
{
|
|
int indirects;
|
|
|
|
/* if nrblocks are contiguous */
|
|
if (chunk) {
|
|
/*
|
|
* With N contiguous data blocks, it need at most
|
|
* N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
|
|
* 2 dindirect blocks
|
|
* 1 tindirect block
|
|
*/
|
|
indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
return indirects + 3;
|
|
}
|
|
/*
|
|
* if nrblocks are not contiguous, worse case, each block touch
|
|
* a indirect block, and each indirect block touch a double indirect
|
|
* block, plus a triple indirect block
|
|
*/
|
|
indirects = nrblocks * 2 + 1;
|
|
return indirects;
|
|
}
|
|
|
|
static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
|
|
{
|
|
if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
|
|
return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
|
|
return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
|
|
}
|
|
|
|
/*
|
|
* Account for index blocks, block groups bitmaps and block group
|
|
* descriptor blocks if modify datablocks and index blocks
|
|
* worse case, the indexs blocks spread over different block groups
|
|
*
|
|
* If datablocks are discontiguous, they are possible to spread over
|
|
* different block groups too. If they are contiugous, with flexbg,
|
|
* they could still across block group boundary.
|
|
*
|
|
* Also account for superblock, inode, quota and xattr blocks
|
|
*/
|
|
int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
|
|
{
|
|
ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
|
|
int gdpblocks;
|
|
int idxblocks;
|
|
int ret = 0;
|
|
|
|
/*
|
|
* How many index blocks need to touch to modify nrblocks?
|
|
* The "Chunk" flag indicating whether the nrblocks is
|
|
* physically contiguous on disk
|
|
*
|
|
* For Direct IO and fallocate, they calls get_block to allocate
|
|
* one single extent at a time, so they could set the "Chunk" flag
|
|
*/
|
|
idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
|
|
|
|
ret = idxblocks;
|
|
|
|
/*
|
|
* Now let's see how many group bitmaps and group descriptors need
|
|
* to account
|
|
*/
|
|
groups = idxblocks;
|
|
if (chunk)
|
|
groups += 1;
|
|
else
|
|
groups += nrblocks;
|
|
|
|
gdpblocks = groups;
|
|
if (groups > ngroups)
|
|
groups = ngroups;
|
|
if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
|
|
gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
|
|
|
|
/* bitmaps and block group descriptor blocks */
|
|
ret += groups + gdpblocks;
|
|
|
|
/* Blocks for super block, inode, quota and xattr blocks */
|
|
ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Calulate the total number of credits to reserve to fit
|
|
* the modification of a single pages into a single transaction,
|
|
* which may include multiple chunks of block allocations.
|
|
*
|
|
* This could be called via ext4_write_begin()
|
|
*
|
|
* We need to consider the worse case, when
|
|
* one new block per extent.
|
|
*/
|
|
int ext4_writepage_trans_blocks(struct inode *inode)
|
|
{
|
|
int bpp = ext4_journal_blocks_per_page(inode);
|
|
int ret;
|
|
|
|
ret = ext4_meta_trans_blocks(inode, bpp, 0);
|
|
|
|
/* Account for data blocks for journalled mode */
|
|
if (ext4_should_journal_data(inode))
|
|
ret += bpp;
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Calculate the journal credits for a chunk of data modification.
|
|
*
|
|
* This is called from DIO, fallocate or whoever calling
|
|
* ext4_get_blocks() to map/allocate a chunk of contigous disk blocks.
|
|
*
|
|
* journal buffers for data blocks are not included here, as DIO
|
|
* and fallocate do no need to journal data buffers.
|
|
*/
|
|
int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
|
|
{
|
|
return ext4_meta_trans_blocks(inode, nrblocks, 1);
|
|
}
|
|
|
|
/*
|
|
* The caller must have previously called ext4_reserve_inode_write().
|
|
* Give this, we know that the caller already has write access to iloc->bh.
|
|
*/
|
|
int ext4_mark_iloc_dirty(handle_t *handle,
|
|
struct inode *inode, struct ext4_iloc *iloc)
|
|
{
|
|
int err = 0;
|
|
|
|
if (test_opt(inode->i_sb, I_VERSION))
|
|
inode_inc_iversion(inode);
|
|
|
|
/* the do_update_inode consumes one bh->b_count */
|
|
get_bh(iloc->bh);
|
|
|
|
/* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
|
|
err = ext4_do_update_inode(handle, inode, iloc);
|
|
put_bh(iloc->bh);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* On success, We end up with an outstanding reference count against
|
|
* iloc->bh. This _must_ be cleaned up later.
|
|
*/
|
|
|
|
int
|
|
ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
|
|
struct ext4_iloc *iloc)
|
|
{
|
|
int err;
|
|
|
|
err = ext4_get_inode_loc(inode, iloc);
|
|
if (!err) {
|
|
BUFFER_TRACE(iloc->bh, "get_write_access");
|
|
err = ext4_journal_get_write_access(handle, iloc->bh);
|
|
if (err) {
|
|
brelse(iloc->bh);
|
|
iloc->bh = NULL;
|
|
}
|
|
}
|
|
ext4_std_error(inode->i_sb, err);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Expand an inode by new_extra_isize bytes.
|
|
* Returns 0 on success or negative error number on failure.
|
|
*/
|
|
static int ext4_expand_extra_isize(struct inode *inode,
|
|
unsigned int new_extra_isize,
|
|
struct ext4_iloc iloc,
|
|
handle_t *handle)
|
|
{
|
|
struct ext4_inode *raw_inode;
|
|
struct ext4_xattr_ibody_header *header;
|
|
struct ext4_xattr_entry *entry;
|
|
|
|
if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
|
|
return 0;
|
|
|
|
raw_inode = ext4_raw_inode(&iloc);
|
|
|
|
header = IHDR(inode, raw_inode);
|
|
entry = IFIRST(header);
|
|
|
|
/* No extended attributes present */
|
|
if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
|
|
header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
|
|
memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
|
|
new_extra_isize);
|
|
EXT4_I(inode)->i_extra_isize = new_extra_isize;
|
|
return 0;
|
|
}
|
|
|
|
/* try to expand with EAs present */
|
|
return ext4_expand_extra_isize_ea(inode, new_extra_isize,
|
|
raw_inode, handle);
|
|
}
|
|
|
|
/*
|
|
* What we do here is to mark the in-core inode as clean with respect to inode
|
|
* dirtiness (it may still be data-dirty).
|
|
* This means that the in-core inode may be reaped by prune_icache
|
|
* without having to perform any I/O. This is a very good thing,
|
|
* because *any* task may call prune_icache - even ones which
|
|
* have a transaction open against a different journal.
|
|
*
|
|
* Is this cheating? Not really. Sure, we haven't written the
|
|
* inode out, but prune_icache isn't a user-visible syncing function.
|
|
* Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
|
|
* we start and wait on commits.
|
|
*
|
|
* Is this efficient/effective? Well, we're being nice to the system
|
|
* by cleaning up our inodes proactively so they can be reaped
|
|
* without I/O. But we are potentially leaving up to five seconds'
|
|
* worth of inodes floating about which prune_icache wants us to
|
|
* write out. One way to fix that would be to get prune_icache()
|
|
* to do a write_super() to free up some memory. It has the desired
|
|
* effect.
|
|
*/
|
|
int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
|
|
{
|
|
struct ext4_iloc iloc;
|
|
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
|
|
static unsigned int mnt_count;
|
|
int err, ret;
|
|
|
|
might_sleep();
|
|
err = ext4_reserve_inode_write(handle, inode, &iloc);
|
|
if (ext4_handle_valid(handle) &&
|
|
EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
|
|
!(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
|
|
/*
|
|
* We need extra buffer credits since we may write into EA block
|
|
* with this same handle. If journal_extend fails, then it will
|
|
* only result in a minor loss of functionality for that inode.
|
|
* If this is felt to be critical, then e2fsck should be run to
|
|
* force a large enough s_min_extra_isize.
|
|
*/
|
|
if ((jbd2_journal_extend(handle,
|
|
EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
|
|
ret = ext4_expand_extra_isize(inode,
|
|
sbi->s_want_extra_isize,
|
|
iloc, handle);
|
|
if (ret) {
|
|
EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
|
|
if (mnt_count !=
|
|
le16_to_cpu(sbi->s_es->s_mnt_count)) {
|
|
ext4_warning(inode->i_sb, __func__,
|
|
"Unable to expand inode %lu. Delete"
|
|
" some EAs or run e2fsck.",
|
|
inode->i_ino);
|
|
mnt_count =
|
|
le16_to_cpu(sbi->s_es->s_mnt_count);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (!err)
|
|
err = ext4_mark_iloc_dirty(handle, inode, &iloc);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* ext4_dirty_inode() is called from __mark_inode_dirty()
|
|
*
|
|
* We're really interested in the case where a file is being extended.
|
|
* i_size has been changed by generic_commit_write() and we thus need
|
|
* to include the updated inode in the current transaction.
|
|
*
|
|
* Also, vfs_dq_alloc_block() will always dirty the inode when blocks
|
|
* are allocated to the file.
|
|
*
|
|
* If the inode is marked synchronous, we don't honour that here - doing
|
|
* so would cause a commit on atime updates, which we don't bother doing.
|
|
* We handle synchronous inodes at the highest possible level.
|
|
*/
|
|
void ext4_dirty_inode(struct inode *inode)
|
|
{
|
|
handle_t *current_handle = ext4_journal_current_handle();
|
|
handle_t *handle;
|
|
|
|
if (!ext4_handle_valid(current_handle)) {
|
|
ext4_mark_inode_dirty(current_handle, inode);
|
|
return;
|
|
}
|
|
|
|
handle = ext4_journal_start(inode, 2);
|
|
if (IS_ERR(handle))
|
|
goto out;
|
|
if (current_handle &&
|
|
current_handle->h_transaction != handle->h_transaction) {
|
|
/* This task has a transaction open against a different fs */
|
|
printk(KERN_EMERG "%s: transactions do not match!\n",
|
|
__func__);
|
|
} else {
|
|
jbd_debug(5, "marking dirty. outer handle=%p\n",
|
|
current_handle);
|
|
ext4_mark_inode_dirty(handle, inode);
|
|
}
|
|
ext4_journal_stop(handle);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
#if 0
|
|
/*
|
|
* Bind an inode's backing buffer_head into this transaction, to prevent
|
|
* it from being flushed to disk early. Unlike
|
|
* ext4_reserve_inode_write, this leaves behind no bh reference and
|
|
* returns no iloc structure, so the caller needs to repeat the iloc
|
|
* lookup to mark the inode dirty later.
|
|
*/
|
|
static int ext4_pin_inode(handle_t *handle, struct inode *inode)
|
|
{
|
|
struct ext4_iloc iloc;
|
|
|
|
int err = 0;
|
|
if (handle) {
|
|
err = ext4_get_inode_loc(inode, &iloc);
|
|
if (!err) {
|
|
BUFFER_TRACE(iloc.bh, "get_write_access");
|
|
err = jbd2_journal_get_write_access(handle, iloc.bh);
|
|
if (!err)
|
|
err = ext4_handle_dirty_metadata(handle,
|
|
inode,
|
|
iloc.bh);
|
|
brelse(iloc.bh);
|
|
}
|
|
}
|
|
ext4_std_error(inode->i_sb, err);
|
|
return err;
|
|
}
|
|
#endif
|
|
|
|
int ext4_change_inode_journal_flag(struct inode *inode, int val)
|
|
{
|
|
journal_t *journal;
|
|
handle_t *handle;
|
|
int err;
|
|
|
|
/*
|
|
* We have to be very careful here: changing a data block's
|
|
* journaling status dynamically is dangerous. If we write a
|
|
* data block to the journal, change the status and then delete
|
|
* that block, we risk forgetting to revoke the old log record
|
|
* from the journal and so a subsequent replay can corrupt data.
|
|
* So, first we make sure that the journal is empty and that
|
|
* nobody is changing anything.
|
|
*/
|
|
|
|
journal = EXT4_JOURNAL(inode);
|
|
if (!journal)
|
|
return 0;
|
|
if (is_journal_aborted(journal))
|
|
return -EROFS;
|
|
|
|
jbd2_journal_lock_updates(journal);
|
|
jbd2_journal_flush(journal);
|
|
|
|
/*
|
|
* OK, there are no updates running now, and all cached data is
|
|
* synced to disk. We are now in a completely consistent state
|
|
* which doesn't have anything in the journal, and we know that
|
|
* no filesystem updates are running, so it is safe to modify
|
|
* the inode's in-core data-journaling state flag now.
|
|
*/
|
|
|
|
if (val)
|
|
EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
|
|
else
|
|
EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
|
|
ext4_set_aops(inode);
|
|
|
|
jbd2_journal_unlock_updates(journal);
|
|
|
|
/* Finally we can mark the inode as dirty. */
|
|
|
|
handle = ext4_journal_start(inode, 1);
|
|
if (IS_ERR(handle))
|
|
return PTR_ERR(handle);
|
|
|
|
err = ext4_mark_inode_dirty(handle, inode);
|
|
ext4_handle_sync(handle);
|
|
ext4_journal_stop(handle);
|
|
ext4_std_error(inode->i_sb, err);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
return !buffer_mapped(bh);
|
|
}
|
|
|
|
int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct page *page = vmf->page;
|
|
loff_t size;
|
|
unsigned long len;
|
|
int ret = -EINVAL;
|
|
void *fsdata;
|
|
struct file *file = vma->vm_file;
|
|
struct inode *inode = file->f_path.dentry->d_inode;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
|
|
/*
|
|
* Get i_alloc_sem to stop truncates messing with the inode. We cannot
|
|
* get i_mutex because we are already holding mmap_sem.
|
|
*/
|
|
down_read(&inode->i_alloc_sem);
|
|
size = i_size_read(inode);
|
|
if (page->mapping != mapping || size <= page_offset(page)
|
|
|| !PageUptodate(page)) {
|
|
/* page got truncated from under us? */
|
|
goto out_unlock;
|
|
}
|
|
ret = 0;
|
|
if (PageMappedToDisk(page))
|
|
goto out_unlock;
|
|
|
|
if (page->index == size >> PAGE_CACHE_SHIFT)
|
|
len = size & ~PAGE_CACHE_MASK;
|
|
else
|
|
len = PAGE_CACHE_SIZE;
|
|
|
|
if (page_has_buffers(page)) {
|
|
/* return if we have all the buffers mapped */
|
|
if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
|
|
ext4_bh_unmapped))
|
|
goto out_unlock;
|
|
}
|
|
/*
|
|
* OK, we need to fill the hole... Do write_begin write_end
|
|
* to do block allocation/reservation.We are not holding
|
|
* inode.i__mutex here. That allow * parallel write_begin,
|
|
* write_end call. lock_page prevent this from happening
|
|
* on the same page though
|
|
*/
|
|
ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
|
|
len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
|
|
if (ret < 0)
|
|
goto out_unlock;
|
|
ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
|
|
len, len, page, fsdata);
|
|
if (ret < 0)
|
|
goto out_unlock;
|
|
ret = 0;
|
|
out_unlock:
|
|
if (ret)
|
|
ret = VM_FAULT_SIGBUS;
|
|
up_read(&inode->i_alloc_sem);
|
|
return ret;
|
|
}
|