ufs super block contains some statistic about file systems, like amount of
directories, free blocks, inodes and so on.
UFS1 hold this information in one location and uses 32bit integers for such
information, UFS2 hold statistic in another location and uses 64bit integers.
There is transition variant, if UFS1 has type 44BSD and flags field in super
block has some special value this mean that we work with statistic like UFS2
does. and this also means that nobody care about old(UFS1) statistic.
So if start fsck against such file system, after usage linux ufs driver, it
found error: at now only UFS1 like statistic is updated.
This patch should fix this. Also it contains some minor cleanup: CodingSytle
and remove unused variables.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Presently ufs doesn't support "fsync", this make some applications unhappy,
for example vim. This patch fixes this situation.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Super block of UFS usually has size >512, because of fragment size may be 512,
this cause some problems.
Currently, there are two methods to work with ufs super block:
1) split structure which describes ufs super blocks into structures with
size <=512
2) use one structure which describes ufs super block, and hope that array
of "buffer_head" which holds "super block", has such construction:
bh[n]->b_data + bh[n]->b_size == bh[n + 1]->b_data
The second variant may cause some problems in the future, and usage of two
variants cause unnecessary code duplication.
This patch remove the second variant. Also patch contains some CodingStyle
fixes.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes two bugs, which introduced by previous patches:
1) Missed "brelse"
2) Sometimes "baseblk" may be wrongly calculated, if i_size is equal to
zero, which lead infinite cycle in "mpage_writepages".
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs/ufs/super.c: In function `ufs_print_super_stuff':
fs/ufs/super.c:103: warning: unsigned int format, different type arg (arg 2) fs/ufs/super.c: In function `ufs2_print_super_stuff': fs/ufs/super.c:147: warning: unsigned int format, different type arg (arg 2) fs/ufs/super.c: In function `ufs_print_cylinder_stuff':
fs/ufs/super.c:175: warning: unsigned int format, different type arg (arg 2)
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Presently if we allocate several "metadata" blocks (pointers to indirect
blocks for example), we fill with zeroes only the first block. This cause
some problems in "truncate" function. Also this patch remove some unused
arguments from several functions and add comments.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
ufs_free_blocks function looks now in so way:
if (err)
goto failed;
lock_super();
failed:
unlock_super();
So if error happen we'll unlock not locked super.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
At now UFS code uses DQUOT_* mechanism, but it also update inode->i_blocks
manually, this cause wrong i_blocks value.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch make little optimization of ufs_find_entry like "ext2" does. Save
number of page and reuse it again in the next call.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently to turn on debug mode "user" has to edit ~10 files, to turn off he
has to do it again.
This patch introduce such changes:
1)turn on(off) debug messages via ".config"
2)remove unnecessary duplication of code
3)make "UFSD" macros more similar to function
4)fix some compiler warnings
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To find new bugs, I suggest revert this patch:
http://lkml.org/lkml/2006/1/31/275 in -mm tree.
So others can test "write support" of UFS.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The writing to UFS file system with block/fragment!=8 may cause bogus
behaviour. The problem in "ufs_bitmap_search" function, which doesn't work
correctly in "block/fragment!=8" case. The idea is stolen from BSD code.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are two ugly macros in ufs code:
#define UCPI_UBH ((struct ufs_buffer_head *)ucpi)
#define USPI_UBH ((struct ufs_buffer_head *)uspi)
when uspi looks like
struct {
struct ufs_buffer_head ;
}
and USPI_UBH has some sence,
ucpi looks like
struct {
struct not_ufs_buffer_head;
}
To prevent bugs in future, this patch convert macros to inline function and
fix "ucpi" structure.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change function in fs/ufs/dir.c and fs/ufs/namei.c to work with pages
instead of straight work with blocks. It fixed such bugs:
* for i in `seq 1 1000`; do touch $i; done - crash system
* mkdir create directory without "." and ".." entries
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This series of patches finished "bugs fixing" mentioned
here http://lkml.org/lkml/2006/1/31/275 .
The main bugs:
* for i in `seq 1 1000`; do touch $i; done - crash system
* mkdir create directory without "." and ".." entries
The suggested solution is work with page cache instead of straight work
with blocks. Such solution has following advantages
* reduce code size and its complexity
* some global locks go away
* fix bugs
The most part of code is stolen from ext2, because of it has similar
directory structure.
Patches testes with UFS1 and UFS2 file systems.
This patch installs i_mapping->a_ops for directory inodes and removes some
duplicated code.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
First of all some necessary notes about UFS by it self: To avoid waste of disk
space the tail of file consists not from blocks (which is ordinary big enough,
16K usually), it consists from fragments(which is ordinary 2K). When file is
growing its tail occupy 1 fragment, 2 fragments... At some stage decision to
allocate whole block is made and all fragments are moved to one block.
How this situation was handled before:
ufs_prepare_write
->block_prepare_write
->ufs_getfrag_block
->...
->ufs_new_fragments:
bh = sb_bread
bh->b_blocknr = result + i;
mark_buffer_dirty (bh);
This is wrong solution, because:
- it didn't take into consideration that there is another cache: "inode page
cache"
- because of sb_getblk uses not b_blocknr, (it uses page->index) to find
certain block, this breaks sb_getblk.
How this situation is handled now: we go though all "page inode cache", if
there are no such page in cache we load it into cache, and change b_blocknr.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* After block allocation, we map it on the same "address" as 8 others
blocks
* We nullify block several times: once in ufs/block.c and once in
block_*write_full_page, and use different "caches" for this.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, ufs write support have two sets of problems: work with files and
work with directories.
This series of patches should solve the first problem.
This patch is similar to http://lkml.org/lkml/2006/1/17/61 this patch
complements it.
The situation the same: in ufs_trunc_(not direct), we read block, check if
count of links to it is equal to one, if so we finish cycle, if not
continue. Because of "count of links" always >=2 this operation cause
infinite cycle and hang up the kernel.
Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix of some spelling errors in fs/freevxfs error messages and comments
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Otherwise we could be racing with truncate/mapping removal.
Problem found/fixed by Nick Piggin <npiggin@suse.de>, logic rewritten
by me.
Signed-off-by: Jens Axboe <axboe@suse.de>
A process flag to indicate whether we are doing sync io is incredibly
ugly. It also causes performance problems when one does a lot of async
io and then proceeds to sync it. Part of the io will go out as async,
and the other part as sync. This causes a disconnect between the
previously submitted io and the synced io. For io schedulers such as CFQ,
this will cause us lost merges and suboptimal behaviour in scheduling.
Remove PF_SYNCWRITE completely from the fsync/msync paths, and let
the O_DIRECT path just directly indicate that the writes are sync
by using WRITE_SYNC instead.
Signed-off-by: Jens Axboe <axboe@suse.de>
Sometimes partitions claim to be larger than the reported capacity of a
disk device. This patch makes the kernel warn about those partitions.
We still permit these patitions to be used. Quoting Andries Brouwer
<Andries.Brouwer@cwi.nl>:
Case 1: The kernel is mistaken about the size of the disk. (There are
commands to clip a disk to a certain capacity, there are jumpers to tell a
disk that it should report a certain capacity etc. Usually this is because
of BIOS bugs. In bad cases the machine will crash in the BIOS and hence fail
to boot if the disk reports full capacity.) In such cases actually accessing
the blocks of the partition may work fine, or may work fine after running an
unclip utility. I wrote "setmax" some years ago precisely for this reason.
Case 2: There was a messy partition table (maybe just a rounding error) but
the actual filesystem on the partition is contained in the physical disk.
Now using the filesystem goes without problem.
Case 3: Both partition and filesystem extend beyond the end of the disk. In
forensic or debugging situations one often uses a copy of the start of a
disk. Now access beyond the end gives an expected I/O error.
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Stephen Cameron <steve.cameron@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Split the checkpoint list of the transaction into two lists. In the first
list we keep the buffers that need to be submitted for IO. In the second
list are kept buffers that were already submitted and we just have to wait
for the IO to complete. This should simplify a handling of checkpoint
lists a bit and can eventually be also a performance gain.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: "Stephen C. Tweedie" <sct@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
list_splice_init(list, head) does unneeded job if it is known that
list_empty(head) == 1. We can use list_replace_init() instead.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The percpu counter data type are changed in this set of patches to support
more users like ext3 who need more than 32 bit to store the free blocks
total in the filesystem.
- Generic perpcu counters data type changes. The size of the global counter
and local counter were explictly specified using s64 and s32. The global
counter is changed from long to s64, while the local counter is changed from
long to s32, so we could avoid doing 64 bit update in most cases.
- Users of the percpu counters are updated to make use of the new
percpu_counter_init() routine now taking an additional parameter to allow
users to pass the initial value of the global counter.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Do a CodingStyle cleanup of fs/binfmt_elf.c and also remove some pointless
casts of kmalloc() return values in the same file.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Steven Rostedt <rostedt@goodmis.org> points out that `rsv' here is usually
NULL, so we should avoid calling kfree().
Also, fix up some nearby whitespace damage.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are a couple of places where JBD has to check to see whether an unneeded
memory allocation was performed. Usually it _was_ needed, so we end up
calling kfree(NULL). We can micro-optimise that by checking the pointer
before calling kfree().
Thanks to Steven Rostedt <rostedt@goodmis.org> for identifying this.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix possible assertion failure in journal_commit_transaction() on
jh->b_next_transaction == NULL (when we are processing BJ_Forget list and
buffer is not jbddirty).
!jbddirty buffers can be placed on BJ_Forget list for example by
journal_forget() or by __dispose_buffer() - generally such buffer means
that it has been freed by this transaction.
Freed buffers should not be reallocated until the transaction has committed
(that's why we have the assertion there) but they *can* be reallocated when
the transaction has already been committed to disk and we are just
processing the BJ_Forget list (as soon as we remove b_committed_data from
the bitmap bh, ext3 will be able to reallocate buffers freed by the
committing transaction). So we have to also count with the case that the
buffer has been reallocated and b_next_transaction has been already set.
And one more subtle point: it can happen that we manage to reallocate the
buffer and also mark it jbddirty. Then we also add the freed buffer to the
checkpoint list of the committing trasaction. But that should do no harm.
Non-jbddirty buffers should be filed to BJ_Reserved and not BJ_Metadata
list. It can actually happen that we refile such buffers during the commit
phase when we reallocate in the running transaction blocks deleted in
committing transaction (and that can happen if the committing transaction
already wrote all the data and is just cleaning up BJ_Forget list).
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: "Stephen C. Tweedie" <sct@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The "count" and "pt" variables are declared and modified by do_poll(), as
well as accessed and written indirectly in the do_pollfd() subroutine.
This patch pulls all handling of these variables into the do_poll()
function, thereby eliminating the odd use of indirection in do_pollfd().
This is done by pulling the "struct pollfd" traversal loop from do_pollfd()
into its only caller do_poll(). As an added bonus, the patch saves a few
clock cycles, and also adds comments to make the code easier to follow.
Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We can now make posix_locks_deadlock() static.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pass the POSIX lock owner ID to the flush operation.
This is useful for filesystems which don't want to store any locking state
in inode->i_flock but want to handle locking/unlocking POSIX locks
internally. FUSE is one such filesystem but I think it possible that some
network filesystems would need this also.
Also add a flag to indicate that a POSIX locking request was generated by
close(), so filesystems using the above feature won't send an extra locking
request in this case.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
locks_remove_posix() can use posix_lock_file() instead of doing the lock
removal by hand. posix_lock_file() now does exacly the same.
The comment about pids no longer applies, posix_lock_file() takes only the
owner into account.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
posix_lock_file() always allocates new locks in advance, even if it's easy to
determine that no allocations will be needed.
Optimize these cases:
- FL_ACCESS flag is set
- Unlocking the whole range
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
posix_lock_file() was too cautious, failing operations on OOM, even if they
didn't actually require an allocation.
This has the disadvantage, that a failing unlock on process exit could lead to
a memory leak. There are two possibilites for this:
- filesystem implements .lock() and calls back to posix_lock_file(). On
cleanup of files_struct locks_remove_posix() is called which should remove all
locks belonging to files_struct. However if filesystem calls
posix_lock_file() which fails, then those locks will never be freed.
- if a file is closed while a lock is blocked, then after acquiring
fcntl_setlk() will undo the lock. But this unlock itself might fail on OOM,
again possibly leaking the lock.
The solution is to move the checking of the allocations until after it is sure
that they will be needed. This will solve the above problem since unlock will
always succeed unless it splits an existing region.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add read_mapping_page() which is used for callers that pass
mapping->a_ops->readpage as the filler for read_cache_page. This removes
some duplication from filesystem code.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Disable Ext2 XIP if the kernel is configured in no-MMU mode as the former
won't build.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement an LSM hook for setting a task's IO priority, similar to the hook
for setting a tasks's nice value.
A previous version of this LSM hook was included in an older version of
multiadm by Jan Engelhardt, although I don't recall it being submitted
upstream.
Also included is the corresponding SELinux hook, which re-uses the setsched
permission in the proccess class.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a writeback_control's `start' and `end' fields are used to
indicate a one-byte-range starting at file offset zero, the required
values of .start=0,.end=0 mean that the ->writepages() implementation
has no way of telling that it is being asked to perform a range
request. Because we're currently overloading (start == 0 && end == 0)
to mean "this is not a write-a-range request".
To make all this sane, the patch changes range of writeback_control.
So caller does: If it is calling ->writepages() to write pages, it
sets range (range_start/end or range_cyclic) always.
And if range_cyclic is true, ->writepages() thinks the range is
cyclic, otherwise it just uses range_start and range_end.
This patch does,
- Add LLONG_MAX, LLONG_MIN, ULLONG_MAX to include/linux/kernel.h
-1 is usually ok for range_end (type is long long). But, if someone did,
range_end += val; range_end is "val - 1"
u64val = range_end >> bits; u64val is "~(0ULL)"
or something, they are wrong. So, this adds LLONG_MAX to avoid nasty
things, and uses LLONG_MAX for range_end.
- All callers of ->writepages() sets range_start/end or range_cyclic.
- Fix updates of ->writeback_index. It seems already bit strange.
If it starts at 0 and ended by check of nr_to_write, this last
index may reduce chance to scan end of file. So, this updates
->writeback_index only if range_cyclic is true or whole-file is
scanned.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: "Vladimir V. Saveliev" <vs@namesys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Current hugetlb strict accounting for shared mapping always assume mapping
starts at zero file offset and reserves pages between zero and size of the
file. This assumption often reserves (or lock down) a lot more pages then
necessary if application maps at none zero file offset. libhugetlbfs is
one example that requires proper reservation on shared mapping starts at
none zero offset.
This patch extends the reservation and hugetlb strict accounting to support
any arbitrary pair of (offset, len), resulting a much more robust and
accurate scheme. More importantly, it won't lock down any hugetlb pages
outside file mapping.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
for_each_cpu() actually iterates across all possible CPUs. We've had mistakes
in the past where people were using for_each_cpu() where they should have been
iterating across only online or present CPUs. This is inefficient and
possibly buggy.
We're renaming for_each_cpu() to for_each_possible_cpu() to avoid this in the
future.
This patch replaces for_each_cpu with for_each_possible_cpu.
in xfs.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Enable XFS to limit the statfs() results to the project quota covering the
dentry used as a base for call.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.
This complements the get_sb() patch. That reduced the significance of
sb->s_root, allowing NFS to place a fake root there. However, NFS does
require a dentry to use as a target for the statfs operation. This permits
the root in the vfsmount to be used instead.
linux/mount.h has been added where necessary to make allyesconfig build
successfully.
Interest has also been expressed for use with the FUSE and XFS filesystems.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Add description of d_lock handling to comments over prune_one_dentry().
- It has three callsites - uninline it, saving 200 bytes of text.
Cc: Jan Blunck <jblunck@suse.de>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Olaf Hering <olh@suse.de>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The race is that the shrink_dcache_memory shrinker could get called while a
filesystem is being unmounted, and could try to prune a dentry belonging to
that filesystem.
If it does, then it will call in to iput on the inode while the dentry is
no longer able to be found by the umounting process. If iput takes a
while, generic_shutdown_super could get all the way though
shrink_dcache_parent and shrink_dcache_anon and invalidate_inodes without
ever waiting on this particular inode.
Eventually the superblock gets freed anyway and if the iput tried to touch
it (which some filesystems certainly do), it will lose. The promised
"Self-destruct in 5 seconds" doesn't lead to a nice day.
The race is closed by holding s_umount while calling prune_one_dentry on
someone else's dentry. As a down_read_trylock is used,
shrink_dcache_memory will no longer try to prune the dentry of a filesystem
that is being unmounted, and unmount will not be able to start until any
such active prune_one_dentry completes.
This requires that prune_dcache *knows* which filesystem (if any) it is
doing the prune on behalf of so that it can be careful of other
filesystems. shrink_dcache_memory isn't called it on behalf of any
filesystem, and so is careful of everything.
shrink_dcache_anon is now passed a super_block rather than the s_anon list
out of the superblock, so it can get the s_anon list itself, and can pass
the superblock down to prune_dcache.
If prune_dcache finds a dentry that it cannot free, it leaves it where it
is (at the tail of the list) and exits, on the assumption that some other
thread will be removing that dentry soon. To try to make sure that some
work gets done, a limited number of dnetries which are untouchable are
skipped over while choosing the dentry to work on.
I believe this race was first found by Kirill Korotaev.
Cc: Jan Blunck <jblunck@suse.de>
Acked-by: Kirill Korotaev <dev@openvz.org>
Cc: Olaf Hering <olh@suse.de>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch removes the steal_locks() function.
steal_locks() doesn't work correctly with any filesystem that does it's own
lock management, including NFS, CIFS, etc.
In addition it has weird semantics on local filesystems in case tasks
sharing file-descriptor tables are doing POSIX locking operations in
parallel to execve().
The steal_locks() function has an effect on applications doing:
clone(CLONE_FILES)
/* in child */
lock
execve
lock
POSIX locks acquired before execve (by "child", "parent" or any further
task sharing files_struct) will after the execve be owned exclusively by
"child".
According to Chris Wright some LSB/LTP kind of suite triggers without the
stealing behavior, but there's no known real-world application that would
also fail.
Apps using NPTL are not affected, since all other threads are killed before
execve.
Apps using LinuxThreads are only affected if they
- have multiple threads during exec (LinuxThreads doesn't kill other
threads, the app may do it with pthread_kill_other_threads_np())
- rely on POSIX locks being inherited across exec
Both conditions are documented, but not their interaction.
Apps using clone() natively are affected if they
- use clone(CLONE_FILES)
- rely on POSIX locks being inherited across exec
The above scenarios are unlikely, but possible.
If the patch is vetoed, there's a plan B, that involves mostly keeping the
weird stealing semantics, but changing the way lock ownership is handled so
that network and local filesystems work consistently.
That would add more complexity though, so this solution seems to be
preferred by most people.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
