Use xfs_perag_get() and xfs_perag_put() in the filestreams code.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Start abstracting the perag references so that the indexing of the
structures is not directly coded into all the places that uses the
perag structures. This will allow us to separate the use of the
perag structure and the way it is indexed and hence avoid the known
deadlocks related to growing a busy filesystem.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
xfs_get_perag is really getting the perag that an inode belongs to
based on it's inode number. Convert the use of this function to just
get the perag from a provided ag number. Use this new function to
obtain the per-ag structure when traversing the per AG inode trees
for sync and reclaim.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
The xfsbufd wakes every xfsbufd_centisecs (once per second by
default) for each filesystem even when the filesystem is idle. If
the xfsbufd has nothing to do, put it into a long term sleep and
only wake it up when there is work pending (i.e. dirty buffers to
flush soon). This will make laptop power misers happy.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Now that the AIL push algorithm is traversal safe, we don't need a
watchdog function in the xfsaild to catch pushes that fail to make
progress. Remove the watchdog timeout and make pushes purely driven
by demand. This will remove the once-per-second wakeup that is seen
when the filesystem is idle and make laptop power misers happy.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Remove the roll-your-own linked list operations.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Just minor housekeeping, a lot more functions can be trivially made
static; others could if we reordered things a bit...
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Alex Elder <aelder@sgi.com>
The swap extent ioctl passes in a target inode and a temporary inode
which are clearly named in the ioctl structure. The code then
assigns temp to target and vice versa, making it extremely difficult
to work out which inode is which later in the code. Make this
consistent throughout the code.
Also make xfs_swap_extent static as there are no external users of
the function.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
To be able to diagnose whether the swap extents function is
detecting compatible inode data fork configurations for swapping
extents, add tracing points to the code to allow us to see the
format of the inode forks before and after the swap.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
When swapping extents, we can corrupt inodes by swapping data forks
that are in incompatible formats. This is caused by the two indoes
having different fork offsets due to the presence of an attribute
fork on an attr2 filesystem. xfs_fsr tries to be smart about
setting the fork offset, but the trick it plays only works on attr1
(old fixed format attribute fork) filesystems.
Changing the way xfs_fsr sets up the attribute fork will prevent
this situation from ever occurring, so in the kernel code we can get
by with a preventative fix - check that the data fork in the
defragmented inode is in a format valid for the inode it is being
swapped into. This will lead to files that will silently and
potentially repeatedly fail defragmentation, so issue a warning to
the log when this particular failure occurs to let us know that
xfs_fsr needs updating/fixing.
To help identify how to improve xfs_fsr to avoid this issue, add
trace points for the inodes being swapped so that we can determine
why the swap was rejected and to confirm that the code is making the
right decisions and modifications when swapping forks.
A further complication is even when the swap is allowed to proceed
when the fork offset is different between the two inodes then value
for the maximum number of extents the data fork can hold can be
wrong. Make sure these are also set correctly after the swap occurs.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
When xfs_rtfind_forw() returns an error, the block is returned
uninitialised. xfs_rtfree_range() is not checking the error return,
so could be using an uninitialised block number for modifying bitmap
summary info.
The problem was found by gcc when compiling the *userspace* libxfs
code - it is an copy of the kernel code with the exact same bug.
gcc gives an uninitialised variable warning on the userspace code
but not on the kernel code. You gotta love the consistency (Mmmm,
slightly chewy today!).
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
When reclaiming stale inodes, we need to guarantee that inodes are
unpinned before returning with a "clean" status. If we don't we can
reclaim inodes that are pinned, leading to use after free in the
transaction subsystem as transactions complete.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
lockdep complains about a the lock not being initialised as we do an
ASSERT based check that the lock is not held before we initialise it
to catch inodes freed with the lock held.
lockdep does this check for us in the lock initialisation code, so
remove the ASSERT to stop the lockdep warning.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
We cannot do direct inode reclaim without taking the flush lock to
ensure that we do not reclaim an inode under IO. We check the inode
is clean before doing direct reclaim, but this is not good enough
because the inode flush code marks the inode clean once it has
copied the in-core dirty state to the backing buffer.
It is the flush lock that determines whether the inode is still
under IO, even though it is marked clean, and the inode is still
required at IO completion so we can't reclaim it even though it is
clean in core. Hence the requirement that we need to take the flush
lock even on clean inodes because this guarantees that the inode
writeback IO has completed and it is safe to reclaim the inode.
With delayed write inode flushing, we coul dend up waiting a long
time on the flush lock even for a clean inode. The background
reclaim already handles this efficiently, so avoid all the problems
by killing the direct reclaim path altogether.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
The reclaim code will handle flushing of dirty inodes before reclaim
occurs, so avoid them when determining whether an inode is a
candidate for flushing to disk when walking the radix trees. This
is based on a test patch from Christoph Hellwig.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Make the inode tree reclaim walk exclusive to avoid races with
concurrent sync walkers and lookups. This is a version of a patch
posted by Christoph Hellwig that avoids all the code duplication.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
There are two copies of list_sort() in the tree already, one in the DRM
code, another in ubifs. Now XFS needs this as well. Create a generic
list_sort() function from the ubifs version and convert existing users
to it so we don't end up with yet another copy in the tree.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Artem Bityutskiy <dedekind@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: Ensure we force all busy extents in range to disk
xfs: Don't flush stale inodes
xfs: fix timestamp handling in xfs_setattr
xfs: use DECLARE_EVENT_CLASS
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-fixes:
GFS2: Use MAX_LFS_FILESIZE for meta inode size
GFS2: Fix gfs2_xattr_acl_chmod()
GFS2: Fix locking bug in rename
GFS2: Ensure uptodate inode size when using O_APPEND
A long time ago we regarded zero page as file_rss and vm_normal_page
doesn't return NULL.
But now, we reinstated ZERO_PAGE and vm_normal_page's implementation can
return NULL in case of zero page. Also we don't count it with file_rss
any more.
Then, RSS and PSS can't be matched. For consistency, Let's ignore zero
page in smaps_pte_range.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Matt Mackall <mpm@selenic.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d899bf7b (procfs: provide stack information for threads) introduced
to show stack information in /proc/{pid}/status. But it cause large
performance regression. Unfortunately /proc/{pid}/status is used ps
command too and ps is one of most important component. Because both to
take mmap_sem and page table walk are heavily operation.
If many process run, the ps performance is,
[before d899bf7b]
% perf stat ps >/dev/null
Performance counter stats for 'ps':
4090.435806 task-clock-msecs # 0.032 CPUs
229 context-switches # 0.000 M/sec
0 CPU-migrations # 0.000 M/sec
234 page-faults # 0.000 M/sec
8587565207 cycles # 2099.425 M/sec
9866662403 instructions # 1.149 IPC
3789415411 cache-references # 926.409 M/sec
30419509 cache-misses # 7.437 M/sec
128.859521955 seconds time elapsed
[after d899bf7b]
% perf stat ps > /dev/null
Performance counter stats for 'ps':
4305.081146 task-clock-msecs # 0.028 CPUs
480 context-switches # 0.000 M/sec
2 CPU-migrations # 0.000 M/sec
237 page-faults # 0.000 M/sec
9021211334 cycles # 2095.480 M/sec
10605887536 instructions # 1.176 IPC
3612650999 cache-references # 839.160 M/sec
23917502 cache-misses # 5.556 M/sec
152.277819582 seconds time elapsed
Thus, this patch revert it. Fortunately /proc/{pid}/task/{tid}/smaps
provide almost same information. we can use it.
Commit d899bf7b introduced two features:
1) Add the annotattion of [thread stack: xxxx] mark to
/proc/{pid}/task/{tid}/maps.
2) Add StackUsage field to /proc/{pid}/status.
I only revert (2), because I haven't seen (1) cause regression.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit fd8fbfc1 modified the way we find amount of reserved space
belonging to an inode. The amount of reserved space is checked
from dquot_transfer and thus inode_reserved_space gets called
even for filesystems that don't provide get_reserved_space callback
which results in a BUG.
Fix the problem by checking get_reserved_space callback and return 0 if
the filesystem does not provide it.
CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Using ~0ULL was cauing sign issues in filemap_fdatawrite_range, so
use MAX_LFS_FILESIZE instead.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
When we search for and find a busy extent during allocation we
force the log out to ensure the extent free transaction is on
disk before the allocation transaction. The current implementation
has a subtle bug in it--it does not handle multiple overlapping
ranges.
That is, if we free lots of little extents into a single
contiguous extent, then allocate the contiguous extent, the busy
search code stops searching at the first extent it finds that
overlaps the allocated range. It then uses the commit LSN of the
transaction to force the log out to.
Unfortunately, the other busy ranges might have more recent
commit LSNs than the first busy extent that is found, and this
results in xfs_alloc_search_busy() returning before all the
extent free transactions are on disk for the range being
allocated. This can lead to potential metadata corruption or
stale data exposure after a crash because log replay won't replay
all the extent free transactions that cover the allocation range.
Modified-by: Alex Elder <aelder@sgi.com>
(Dropped the "found" argument from the xfs_alloc_busysearch trace
event.)
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Because inodes remain in cache much longer than inode buffers do
under memory pressure, we can get the situation where we have
stale, dirty inodes being reclaimed but the backing storage has
been freed. Hence we should never, ever flush XFS_ISTALE inodes
to disk as there is no guarantee that the backing buffer is in
cache and still marked stale when the flush occurs.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
We currently have some rather odd code in xfs_setattr for
updating the a/c/mtime timestamps:
- first we do a non-transaction update if all three are updated
together
- second we implicitly update the ctime for various changes
instead of relying on the ATTR_CTIME flag
- third we set the timestamps to the current time instead of the
arguments in the iattr structure in many cases.
This patch makes sure we update it in a consistent way:
- always transactional
- ctime is only updated if ATTR_CTIME is set or we do a size
update, which is a special case
- always to the times passed in from the caller instead of the
current time
The only non-size caller of xfs_setattr that doesn't come from
the VFS is updated to set ATTR_CTIME and pass in a valid ctime
value.
Reported-by: Eric Blake <ebb9@byu.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
Using DECLARE_EVENT_CLASS allows us to to use trace event code
instead of duplicating it in the binary. This was not available
before 2.6.33 so it had to be done as a separate step once the
prerequisite was merged.
This only requires changes to xfs_trace.h and the results are
rather impressive:
hch@brick:~/work/linux-2.6/obj-kvm$ size fs/xfs/xfs.o*
text data bss dec hex filename
607732 41884 3616 653232 9f7b0 fs/xfs/xfs.o
1026732 41884 3808 1072424 105d28 fs/xfs/xfs.o.old
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
nfs: fix oops in nfs_rename()
sunrpc: fix build-time warning
sunrpc: on successful gss error pipe write, don't return error
SUNRPC: Fix the return value in gss_import_sec_context()
SUNRPC: Fix up an error return value in gss_import_sec_context_kerberos()
Randy Dunlap Reported printk() format-related warnings reported
on i386 builds in his environment. Dave Chinner provided this
patch to eliminate them.
Signed-off by: Dave Chinner <david@fromorbit.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
The ref counting for the bh returned by gfs2_ea_find() was
wrong. This patch ensures that we always drop the ref count
to that bh correctly.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The rename code was taking a resource group lock in cases where
it wasn't actually needed, this caused problems if the rename
was resulting in an inode being unlinked. The patch ensures that
we only take the rgrp lock early if it is really needed.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
The VFS reads the inode size during generic_file_aio_write() but
with no locking around it. In order to get the expected result
from O_APPEND opens, this patch updated the inode size before
calling generic_file_aio_write()
There is of course still a race here, in that there is nothing to
prevent another node coming in and extending the file in the
mean time. On the other hand, when used with file locking this
will ensure that the expected results are obtained.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Fix remaining xattr locks acquired in reiserfs_xattr_set_handle()
while we are holding the reiserfs lock to avoid lock inversions.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Stanse found an unreachable statement in reiserfs_ioctl. There is a
if followed by error assignment and `break' with no braces. Add the
braces so that we don't break every time, but only in error case,
so that REISERFS_IOC_SETVERSION actually works when it returns no
error.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Reiserfs <reiserfs-devel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
reiserfs_get_acl is usually not called under the reiserfs lock,
as it doesn't need it. But it happens when it is called by
reiserfs_acl_chmod(), which creates a dependency inversion against
the private xattr inodes mutexes for the given inode.
We need to call it without the reiserfs lock, especially since
it's unnecessary.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
The current code will load the stack size and protection markings, but
then only use the markings in the MMU code path. The NOMMU code path
always passes PROT_EXEC to the mmap() call. While this doesn't matter
to most people whilst the code is running, it will cause a pointless
icache flush when starting every FDPIC application. Typically this
icache flush will be of a region on the order of 128KB in size, or may
be the entire icache, depending on the facilities available on the CPU.
In the case where the arch default behaviour seems to be desired
(EXSTACK_DEFAULT), we probe VM_STACK_FLAGS for VM_EXEC to determine
whether we should be setting PROT_EXEC or not.
For arches that support an MPU (Memory Protection Unit - an MMU without
the virtual mapping capability), setting PROT_EXEC or not will make an
important difference.
It should be noted that this change also affects the executability of
the brk region, since ELF-FDPIC has that share with the stack. However,
this is probably irrelevant as NOMMU programs aren't likely to use the
brk region, preferring instead allocation via mmap().
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-2.6.33' of git://linux-nfs.org/~bfields/linux:
sunrpc: fix peername failed on closed listener
nfsd: make sure data is on disk before calling ->fsync
nfsd: fix "insecure" export option
Recent change is missing to update "rehash". With that change, it will
become the cause of adding dentry to hash twice.
This explains the reason of Oops (dereference the freed dentry in
__d_lookup()) on my machine.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: Marvin <marvin24@gmx.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
nfsd is not using vfs_fsync, so I missed it when changing the calling
convention during the 2.6.32 window. This patch fixes it to not only
start the data writeout, but also wait for it to complete before calling
into ->fsync.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
* 'for-linus' of git://git.open-osd.org/linux-open-osd:
exofs: simple_write_end does not mark_inode_dirty
exofs: fix pnfs_osd re-definitions in pre-pnfs trees
exofs uses simple_write_end() for it's .write_end handler. But
it is not enough because simple_write_end() does not call
mark_inode_dirty() when it extends i_size. So even if we do
call mark_inode_dirty at beginning of write out, with a very
long IO and a saturated system we might get the .write_inode()
called while still extend-writing to file and miss out on the last
i_size updates.
So override .write_end, call simple_write_end(), and afterwords if
i_size was changed call mark_inode_dirty().
It stands to logic that since simple_write_end() was the one extending
i_size it should also call mark_inode_dirty(). But it looks like all
users of simple_write_end() are memory-bound pseudo filesystems, who
could careless about mark_inode_dirty(). I might submit a
warning-comment patch to simple_write_end() in future.
CC: Stable <stable@kernel.org>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Some on disk exofs constants and types are defined in the pnfs_osd_xdr.h
file. Since we needed these types before the pnfs-objects code was
accepted to mainline we duplicated the minimal needed definitions into
an exofs local header. The definitions where conditionally included
depending on !CONFIG_PNFS defined. So if PNFS was present in the tree
definitions are taken from there and if not they are defined locally.
That was all good but, the CONFIG_PNFS is planed to be included upstream
before the pnfs-objects is also included. (The first pnfs batch might be
pnfs-files only)
So condition exofs local definitions on the absence of pnfs_osd_xdr.h
inclusion (__PNFS_OSD_XDR_H__ not defined). User code must make sure
that in future pnfs_osd_xdr.h will be included before fs/exofs/pnfs.h,
which happens to be so in current code.
Once pnfs-objects hits mainline, exofs's local header will be removed.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
When we remove an xattr, we call lookup_and_delete_xattr()
that takes some private xattr inodes mutexes. But we hold
the reiserfs lock at this time, which leads to dependency
inversions.
We can safely call lookup_and_delete_xattr() without the
reiserfs lock, where xattr inodes lookups only need the
xattr inodes mutexes.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
On chown, reiserfs will call reiserfs_setattr() to change the owner
of the given inode, but it may also recursively call
reiserfs_setattr() to propagate the owner change to the private xattr
files for this inode.
Hence, the reiserfs lock may be acquired twice which is not wanted
as reiserfs_setattr() calls journal_begin() that is going to try to
relax the lock in order to safely acquire the journal mutex.
Using reiserfs_write_lock_once() from reiserfs_setattr() solves
the problem.
This fixes the following warning, that precedes a lockdep report.
WARNING: at fs/reiserfs/lock.c:95 reiserfs_lock_check_recursive+0x3f/0x50()
Hardware name: MS-7418
Unwanted recursive reiserfs lock!
Pid: 4189, comm: fsstress Not tainted 2.6.33-rc2-tip-atom+ #195
Call Trace:
[<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
[<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
[<c103f7ac>] warn_slowpath_common+0x6c/0xc0
[<c1178bff>] ? reiserfs_lock_check_recursive+0x3f/0x50
[<c103f84b>] warn_slowpath_fmt+0x2b/0x30
[<c1178bff>] reiserfs_lock_check_recursive+0x3f/0x50
[<c1172ae3>] do_journal_begin_r+0x83/0x350
[<c1172f2d>] journal_begin+0x7d/0x140
[<c106509a>] ? in_group_p+0x2a/0x30
[<c10fda71>] ? inode_change_ok+0x91/0x140
[<c115007d>] reiserfs_setattr+0x15d/0x2e0
[<c10f9bf3>] ? dput+0xe3/0x140
[<c1465adc>] ? _raw_spin_unlock+0x2c/0x50
[<c117831d>] chown_one_xattr+0xd/0x10
[<c11780a3>] reiserfs_for_each_xattr+0x113/0x2c0
[<c1178310>] ? chown_one_xattr+0x0/0x10
[<c14641e9>] ? mutex_lock_nested+0x2a9/0x350
[<c117826f>] reiserfs_chown_xattrs+0x1f/0x60
[<c106509a>] ? in_group_p+0x2a/0x30
[<c10fda71>] ? inode_change_ok+0x91/0x140
[<c1150046>] reiserfs_setattr+0x126/0x2e0
[<c1177c20>] ? reiserfs_getxattr+0x0/0x90
[<c11b0d57>] ? cap_inode_need_killpriv+0x37/0x50
[<c10fde01>] notify_change+0x151/0x330
[<c10e659f>] chown_common+0x6f/0x90
[<c10e67bd>] sys_lchown+0x6d/0x80
[<c1002ccc>] sysenter_do_call+0x12/0x32
---[ end trace 7c2b77224c1442fc ]---
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Holding locks over device_del -> kobject_del -> sysfs_deactivate can
cause deadlocks if those same locks are grabbed in sysfs show or store
methods.
The I model s_active count + completion as a sleeping read/write lock.
I describe to lockdep sysfs_get_active as a read_trylock,
sysfs_put_active as a read_unlock, and sysfs_deactivate as a
write_lock and write_unlock pair. This seems to capture the essence
for purposes of finding deadlocks, and in my testing gives finds real
issues and ignores non-issues.
This brings us back to holding locks over kobject_del is a problem
that ideally we should find a way of addressing, but at least lockdep
can tell us about the problems instead of requiring developers to debug
rare strange system deadlocks, that happen when sysfs files are removed
while being written to.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Chinner