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Merge branch 'ext3-latency-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

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* 'ext3-latency-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext3: Try to avoid starting a transaction in writepage for data=writepage
  block_write_full_page: switch synchronous writes to use WRITE_SYNC_PLUG
This commit is contained in:
Linus Torvalds 2009-04-08 17:42:32 -07:00
commit a7b334de4d
2 changed files with 30 additions and 6 deletions
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13
fs/buffer.c
View File

@ -1596,6 +1596,16 @@ EXPORT_SYMBOL(unmap_underlying_metadata);
* locked buffer. This only can happen if someone has written the buffer
* directly, with submit_bh(). At the address_space level PageWriteback
* prevents this contention from occurring.
*
* If block_write_full_page() is called with wbc->sync_mode ==
* WB_SYNC_ALL, the writes are posted using WRITE_SYNC_PLUG; this
* causes the writes to be flagged as synchronous writes, but the
* block device queue will NOT be unplugged, since usually many pages
* will be pushed to the out before the higher-level caller actually
* waits for the writes to be completed. The various wait functions,
* such as wait_on_writeback_range() will ultimately call sync_page()
* which will ultimately call blk_run_backing_dev(), which will end up
* unplugging the device queue.
*/
static int __block_write_full_page(struct inode *inode, struct page *page,
get_block_t *get_block, struct writeback_control *wbc)
@ -1606,7 +1616,8 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
struct buffer_head *bh, *head;
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
int write_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
WRITE_SYNC_PLUG : WRITE);
BUG_ON(!PageLocked(page));

23
fs/ext3/inode.c
View File

@ -1521,12 +1521,16 @@ static int ext3_ordered_writepage(struct page *page,
if (!page_has_buffers(page)) {
create_empty_buffers(page, inode->i_sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
} else if (!walk_page_buffers(NULL, page_buffers(page), 0, PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
/* Provide NULL instead of get_block so that we catch bugs if buffers weren't really mapped */
return block_write_full_page(page, NULL, wbc);
page_bufs = page_buffers(page);
} else {
page_bufs = page_buffers(page);
if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
NULL, buffer_unmapped)) {
/* Provide NULL get_block() to catch bugs if buffers
* weren't really mapped */
return block_write_full_page(page, NULL, wbc);
}
}
page_bufs = page_buffers(page);
handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
@ -1581,6 +1585,15 @@ static int ext3_writeback_writepage(struct page *page,
if (ext3_journal_current_handle())
goto out_fail;
if (page_has_buffers(page)) {
if (!walk_page_buffers(NULL, page_buffers(page), 0,
PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
/* Provide NULL get_block() to catch bugs if buffers
* weren't really mapped */
return block_write_full_page(page, NULL, wbc);
}
}
handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);