Commit Graph

1807 Commits (e09b457bdb7e8d23fc54dcef0930ac697d8de895)

Author SHA1 Message Date
Dave Chinner 80168676eb xfs: force background CIL push under sustained load
I have been seeing occasional pauses in transaction throughput up to
30s long under heavy parallel workloads. The only notable thing was
that the xfsaild was trying to be active during the pauses, but
making no progress. It was running exactly 20 times a second (on the
50ms no-progress backoff), and the number of pushbuf events was
constant across this time as well.  IOWs, the xfsaild appeared to be
stuck on buffers that it could not push out.

Further investigation indicated that it was trying to push out inode
buffers that were pinned and/or locked. The xfsbufd was also getting
woken at the same frequency (by the xfsaild, no doubt) to push out
delayed write buffers. The xfsbufd was not making any progress
because all the buffers in the delwri queue were pinned. This scan-
and-make-no-progress dance went one in the trace for some seconds,
before the xfssyncd came along an issued a log force, and then
things started going again.

However, I noticed something strange about the log force - there
were way too many IO's issued. 516 log buffers were written, to be
exact. That added up to 129MB of log IO, which got me very
interested because it's almost exactly 25% of the size of the log.
He delayed logging code is suppose to aggregate the minimum of 25%
of the log or 8MB worth of changes before flushing. That's what
really puzzled me - why did a log force write 129MB instead of only
8MB?

Essentially what has happened is that no CIL pushes had occurred
since the previous tail push which cleared out 25% of the log space.
That caused all the new transactions to block because there wasn't
log space for them, but they kick the xfsaild to push the tail.
However, the xfsaild was not making progress because there were
buffers it could not lock and flush, and the xfsbufd could not flush
them because they were pinned. As a result, both the xfsaild and the
xfsbufd could not move the tail of the log forward without the CIL
first committing.

The cause of the problem was that the background CIL push, which
should happen when 8MB of aggregated changes have been committed, is
being held off by the concurrent transaction commit load. The
background push does a down_write_trylock() which will fail if there
is a concurrent transaction commit holding the push lock in read
mode. With 8 CPUs all doing transactions as fast as they can, there
was enough concurrent transaction commits to hold off the background
push until tail-pushing could no longer free log space, and the halt
would occur.

It should be noted that there is no reason why it would halt at 25%
of log space used by a single CIL checkpoint. This bug could
definitely violate the "no transaction should be larger than half
the log" requirement and hence result in corruption if the system
crashed under heavy load. This sort of bug is exactly the reason why
delayed logging was tagged as experimental....

The fix is to start blocking background pushes once the threshold
has been exceeded. Rework the threshold calculations to keep the
amount of log space a CIL checkpoint can use to below that of the
AIL push threshold to avoid the problem completely.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-09-29 07:51:03 -05:00
Christoph Hellwig dd3932eddf block: remove BLKDEV_IFL_WAIT
All the blkdev_issue_* helpers can only sanely be used for synchronous
caller.  To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead.  So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout.  For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-16 20:52:58 +02:00
Dave Chinner 51749e47e1 xfs: log IO completion workqueue is a high priority queue
The workqueue implementation in 2.6.36-rcX has changed, resulting
in the workqueues no longer having dedicated threads for work
processing. This has caused severe livelocks under heavy parallel
create workloads because the log IO completions have been getting
held up behind metadata IO completions.  Hence log commits would
stall, memory allocation would stall because pages could not be
cleaned, and lock contention on the AIL during inode IO completion
processing was being seen to slow everything down even further.

By making the log Io completion workqueue a high priority workqueue,
they are queued ahead of all data/metadata IO completions and
processed before the data/metadata completions. Hence the log never
gets stalled, and operations needed to clean memory can continue as
quickly as possible. This avoids the livelock conditions and allos
the system to keep running under heavy load as per normal.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-09-10 10:16:54 -05:00
Dan Rosenberg a122eb2fdf xfs: prevent reading uninitialized stack memory
The XFS_IOC_FSGETXATTR ioctl allows unprivileged users to read 12
bytes of uninitialized stack memory, because the fsxattr struct
declared on the stack in xfs_ioc_fsgetxattr() does not alter (or zero)
the 12-byte fsx_pad member before copying it back to the user.  This
patch takes care of it.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-09-10 07:39:28 -05:00
Christoph Hellwig 80f6c29d8a xfs: replace barriers with explicit flush / FUA usage
Switch to the WRITE_FLUSH_FUA flag for log writes and remove the EOPNOTSUPP
detection for barriers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-10 12:35:38 +02:00
Alex Elder cb7a93412a Merge branch '2.6.36-xfs-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev 2010-09-03 09:02:32 -05:00
Tao Ma 9af2546508 xfs: Make fiemap work with sparse files
In xfs_vn_fiemap, we set bvm_count to fi_extent_max + 1 and want
to return fi_extent_max extents, but actually it won't work for
a sparse file. The reason is that in xfs_getbmap we will
calculate holes and set it in 'out', while out is malloced by
bmv_count(fi_extent_max+1) which didn't consider holes. So in the
worst case, if 'out' vector looks like
[hole, extent, hole, extent, hole, ... hole, extent, hole],
we will only return half of fi_extent_max extents.

This patch add a new parameter BMV_IF_NO_HOLES for bvm_iflags.
So with this flags, we don't use our 'out' in xfs_getbmap for
a hole. The solution is a bit ugly by just don't increasing
index of 'out' vector. I felt that it is not easy to skip it
at the very beginning since we have the complicated check and
some function like xfs_getbmapx_fix_eof_hole to adjust 'out'.

Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-09-03 09:02:11 -05:00
Dave Chinner 72656c46f5 xfs: prevent 32bit overflow in space reservation
If we attempt to preallocate more than 2^32 blocks of space in a
single syscall, the transaction block reservation will overflow
leading to a hangs in the superblock block accounting code. This
is trivially reproduced with xfs_io. Fix the problem by capping the
allocation reservation to the maximum number of blocks a single
xfs_bmapi() call can allocate (2^21 blocks).

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-09-03 12:19:33 +10:00
Arkadiusz Mi?kiewicz 23963e54ce xfs: Disallow 32bit project quota id
Currently on-disk structure is able to keep only 16bit project quota
id, so disallow 32bit ones. This fixes a problem where parts of
kernel structures holding project quota id are 32bit while parts
(on-disk) are 16bit variables which causes project quota member
files to be inaccessible for some operations (like mv/rm).

Signed-off-by: Arkadiusz Mi?kiewicz <arekm@maven.pl>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-09-02 10:29:08 -05:00
Dave Chinner 9bc08a45fb xfs: improve buffer cache hash scalability
When doing large parallel file creates on a 16p machines, large amounts of
time is being spent in _xfs_buf_find(). A system wide profile with perf top
shows this:

          1134740.00 19.3% _xfs_buf_find
           733142.00 12.5% __ticket_spin_lock

The problem is that the hash contains 45,000 buffers, and the hash table width
is only 256 buffers. That means we've got around 200 buffers per chain, and
searching it is quite expensive. The hash table size needs to increase.

Secondly, every time we do a lookup, we promote the buffer we find to the head
of the hash chain. This is causing cachelines to be dirtied and causes
invalidation of cachelines across all CPUs that may have walked the hash chain
recently. hence every walk of the hash chain is effectively a cold cache walk.
Remove the promotion to avoid this invalidation.

The results are:

          1045043.00 21.2% __ticket_spin_lock
           326184.00  6.6% _xfs_buf_find

A 70% drop in the CPU usage when looking up buffers. Unfortunately that does
not result in an increase in performance underthis workload as contention on
the inode_lock soaks up most of the reduction in CPU usage.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-09-02 15:14:38 +10:00
Christoph Hellwig b5420f2359 xfs: do not discard page cache data on EAGAIN
If xfs_map_blocks returns EAGAIN because of lock contention we must redirty the
page and not disard the pagecache content and return an error from writepage.
We used to do this correctly, but the logic got lost during the recent
reshuffle of the writepage code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Mike Gao <ygao.linux@gmail.com>
Tested-by: Mike Gao <ygao.linux@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
2010-08-24 11:47:51 +10:00
Dave Chinner 3b93c7aaef xfs: don't do memory allocation under the CIL context lock
Formatting items requires memory allocation when using delayed
logging. Currently that memory allocation is done while holding the
CIL context lock in read mode. This means that if memory allocation
takes some time (e.g. enters reclaim), we cannot push on the CIL
until the allocation(s) required by formatting complete. This can
stall CIL pushes for some time, and once a push is stalled so are
all new transaction commits.

Fix this splitting the item formatting into two steps. The first
step which does the allocation and memcpy() into the allocated
buffer is now done outside the CIL context lock, and only the CIL
insert is done inside the CIL context lock. This avoids the stall
issue.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:45:53 +10:00
Dave Chinner a44f13edf0 xfs: Reduce log force overhead for delayed logging
Delayed logging adds some serialisation to the log force process to
ensure that it does not deference a bad commit context structure
when determining if a CIL push is necessary or not. It does this by
grabing the CIL context lock exclusively, then dropping it before
pushing the CIL if necessary. This causes serialisation of all log
forces and pushes regardless of whether a force is necessary or not.
As a result fsync heavy workloads (like dbench) can be significantly
slower with delayed logging than without.

To avoid this penalty, copy the current sequence from the context to
the CIL structure when they are swapped. This allows us to do
unlocked checks on the current sequence without having to worry
about dereferencing context structures that may have already been
freed. Hence we can remove the CIL context locking in the forcing
code and only call into the push code if the current context matches
the sequence we need to force.

By passing the sequence into the push code, we can check the
sequence again once we have the CIL lock held exclusive and abort if
the sequence has already been pushed. This avoids a lock round-trip
and unnecessary CIL pushes when we have racing push calls.

The result is that the regression in dbench performance goes away -
this change improves dbench performance on a ramdisk from ~2100MB/s
to ~2500MB/s. This compares favourably to not using delayed logging
which retuns ~2500MB/s for the same workload.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:40:03 +10:00
Dave Chinner 1a387d3be2 xfs: dummy transactions should not dirty VFS state
When we  need to cover the log, we issue dummy transactions to ensure
the current log tail is on disk. Unfortunately we currently use the
root inode in the dummy transaction, and the act of committing the
transaction dirties the inode at the VFS level.

As a result, the VFS writeback of the dirty inode will prevent the
filesystem from idling long enough for the log covering state
machine to complete. The state machine gets stuck in a loop issuing
new dummy transactions to cover the log and never makes progress.

To avoid this problem, the dummy transactions should not cause
externally visible state changes. To ensure this occurs, make sure
that dummy transactions log an unchanging field in the superblock as
it's state is never propagated outside the filesystem. This allows
the log covering state machine to complete successfully and the
filesystem now correctly enters a fully idle state about 90s after
the last modification was made.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:46:31 +10:00
Stuart Brodsky 2fe33661fc xfs: ensure f_ffree returned by statfs() is non-negative
Because of delayed updates to sb_icount field in the super block, it
is possible to allocate over maxicount number of inodes.  This
causes the arithmetic to calculate a negative number of free inodes
in user commands like df or stat -f.

Since maxicount is a somewhat arbitrary number, a slight over
allocation is not critical but user commands should be displayed as
0 or greater and never go negative.  To do this the value in the
stats buffer f_ffree is capped to never go negative.

[ Modified to use max_t as per Christoph's comment. ]

Signed-off-by: Stu Brodsky <sbrodsky@sgi.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
2010-08-24 11:46:05 +10:00
Dave Chinner efceab1d56 xfs: handle negative wbc->nr_to_write during sync writeback
During data integrity (WB_SYNC_ALL) writeback, wbc->nr_to_write will
go negative on inodes with more than 1024 dirty pages due to
implementation details of write_cache_pages(). Currently XFS will
abort page clustering in writeback once nr_to_write drops below
zero, and so for data integrity writeback we will do very
inefficient page at a time allocation and IO submission for inodes
with large numbers of dirty pages.

Fix this by only aborting the page clustering code when
wbc->nr_to_write is negative and the sync mode is WB_SYNC_NONE.

Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:44:56 +10:00
Dave Chinner 4536f2ad8b xfs: fix untrusted inode number lookup
Commit 7124fe0a5b ("xfs: validate untrusted inode
numbers during lookup") changes the inode lookup code to do btree lookups for
untrusted inode numbers. This change made an invalid assumption about the
alignment of inodes and hence incorrectly calculated the first inode in the
cluster. As a result, some inode numbers were being incorrectly considered
invalid when they were actually valid.

The issue was not picked up by the xfstests suite because it always runs fsr
and dump (the two utilities that utilise the bulkstat interface) on cache hot
inodes and hence the lookup code in the cold cache path was not sufficiently
exercised to uncover this intermittent problem.

Fix the issue by relaxing the btree lookup criteria and then checking if the
record returned contains the inode number we are lookup for. If it we get an
incorrect record, then the inode number is invalid.

Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:42:30 +10:00
Dave Chinner 5b3eed756c xfs: ensure we mark all inodes in a freed cluster XFS_ISTALE
Under heavy load parallel metadata loads (e.g. dbench), we can fail
to mark all the inodes in a cluster being freed as XFS_ISTALE as we
skip inodes we cannot get the XFS_ILOCK_EXCL or the flush lock on.
When this happens and the inode cluster buffer has already been
marked stale and freed, inode reclaim can try to write the inode out
as it is dirty and not marked stale. This can result in writing th
metadata to an freed extent, or in the case it has already
been overwritten trigger a magic number check failure and return an
EUCLEAN error such as:

Filesystem "ram0": inode 0x442ba1 background reclaim flush failed with 117

Fix this by ensuring that we hoover up all in memory inodes in the
cluster and mark them XFS_ISTALE when freeing the cluster.

Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:42:41 +10:00
Dave Chinner d17c701ce6 xfs: unlock items before allowing the CIL to commit
When we commit a transaction using delayed logging, we need to
unlock the items in the transaciton before we unlock the CIL context
and allow it to be checkpointed. If we unlock them after we release
the CIl context lock, the CIL can checkpoint and complete before
we free the log items. This breaks stale buffer item unlock and
unpin processing as there is an implicit assumption that the unlock
will occur before the unpin.

Also, some log items need to store the LSN of the transaction commit
in the item (inodes and EFIs) and so can race with other transaction
completions if we don't prevent the CIL from checkpointing before
the unlock occurs.

Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-08-24 11:42:52 +10:00
Linus Torvalds 5f248c9c25 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (96 commits)
  no need for list_for_each_entry_safe()/resetting with superblock list
  Fix sget() race with failing mount
  vfs: don't hold s_umount over close_bdev_exclusive() call
  sysv: do not mark superblock dirty on remount
  sysv: do not mark superblock dirty on mount
  btrfs: remove junk sb_dirt change
  BFS: clean up the superblock usage
  AFFS: wait for sb synchronization when needed
  AFFS: clean up dirty flag usage
  cifs: truncate fallout
  mbcache: fix shrinker function return value
  mbcache: Remove unused features
  add f_flags to struct statfs(64)
  pass a struct path to vfs_statfs
  update VFS documentation for method changes.
  All filesystems that need invalidate_inode_buffers() are doing that explicitly
  convert remaining ->clear_inode() to ->evict_inode()
  Make ->drop_inode() just return whether inode needs to be dropped
  fs/inode.c:clear_inode() is gone
  fs/inode.c:evict() doesn't care about delete vs. non-delete paths now
  ...

Fix up trivial conflicts in fs/nilfs2/super.c
2010-08-10 11:26:52 -07:00
Al Viro b57922d97f convert remaining ->clear_inode() to ->evict_inode()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:48:37 -04:00
Al Viro a4ffdde6e5 simplify checks for I_CLEAR/I_FREEING
add I_CLEAR instead of replacing I_FREEING with it.  I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information.  As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:44 -04:00
Christoph Hellwig fa9b227e90 xfs: new truncate sequence
Convert XFS to the new truncate sequence.  We still can have errors after
updating the file size in xfs_setattr, but these are real I/O errors and lead
to a transaction abort and filesystem shutdown, so they are not an issue.

Errors from ->write_begin and write_end can now be handled correctly because
we can actually get rid of the delalloc extents while previous the buffer
state was stipped in block_invalidatepage.

There is still no error handling for ->direct_IO, because doing so will need
some major restructuring given that we only have the iolock shared and do not
hold i_mutex at all.  Fortunately leaving the normally allocated blocks behind
there is not a major issue and this will get cleaned up by xfs_free_eofblock
later.

Note: the patch is against Al's vfs.git tree as that contains the nessecary
preparations.  I'd prefer to get it applied there so that we can get some
testing in linux-next.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:42 -04:00
Christoph Hellwig 155130a4f7 get rid of block_write_begin_newtrunc
Move the call to vmtruncate to get rid of accessive blocks to the callers
in preparation of the new truncate sequence and rename the non-truncating
version to block_write_begin.

While we're at it also remove several unused arguments to block_write_begin.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:33 -04:00
Christoph Hellwig eafdc7d190 sort out blockdev_direct_IO variants
Move the call to vmtruncate to get rid of accessive blocks to the callers
in prepearation of the new truncate calling sequence.  This was only done
for DIO_LOCKING filesystems, so the __blockdev_direct_IO_newtrunc variant
was not needed anyway.  Get rid of blockdev_direct_IO_no_locking and
its _newtrunc variant while at it as just opencoding the two additional
paramters is shorted than the name suffix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09 16:47:29 -04:00
Linus Torvalds 90e0c22596 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6:
  ext3: Fix dirtying of journalled buffers in data=journal mode
  ext3: default to ordered mode
  quota: Use mark_inode_dirty_sync instead of mark_inode_dirty
  quota: Change quota error message to print out disk and function name
  MAINTAINERS: Update entries of ext2 and ext3
  MAINTAINERS: Update address of Andreas Dilger
  ext3: Avoid filesystem corruption after a crash under heavy delete load
  ext3: remove vestiges of nobh support
  ext3: Fix set but unused variables
  quota: clean up quota active checks
  quota: Clean up the namespace in dqblk_xfs.h
  quota: check quota reservation on remove_dquot_ref
2010-08-07 12:57:07 -07:00
Christoph Hellwig 209fb87a25 xfs simplify and speed up direct I/O completions
Our current handling of direct I/O completions is rather suboptimal,
because we defer it to a workqueue more often than needed, and we
perform a much to aggressive flush of the workqueue in case unwritten
extent conversions happen.

This patch changes the direct I/O reads to not even use a completion
handler, as we don't bother to use it at all, and to perform the unwritten
extent conversions in caller context for synchronous direct I/O.

For a small I/O size direct I/O workload on a consumer grade SSD, such as
the untar of a kernel tree inside qemu this patch gives speedups of
about 5%.  Getting us much closer to the speed of a native block device,
or a fully allocated XFS file.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 16:09:19 -05:00
Christoph Hellwig fb511f2150 xfs: move aio completion after unwritten extent conversion
If we write into an unwritten extent using AIO we need to complete the AIO
request after the extent conversion has finished.  Without that a read could
race to see see the extent still unwritten and return zeros.   For synchronous
I/O we already take care of that by flushing the xfsconvertd workqueue (which
might be a bit of overkill).

To do that add iocb and result fields to struct xfs_ioend, so that we can
call aio_complete from xfs_end_io after the extent conversion has happened.
Note that we need a new result field as io_error is used for positive errno
values, while the AIO code can return negative error values and positive
transfer sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 16:09:10 -05:00
Christoph Hellwig 40e2e97316 direct-io: move aio_complete into ->end_io
Filesystems with unwritten extent support must not complete an AIO request
until the transaction to convert the extent has been commited.  That means
the aio_complete calls needs to be moved into the ->end_io callback so
that the filesystem can control when to call it exactly.

This makes a bit of a mess out of dio_complete and the ->end_io callback
prototype even more complicated.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 16:09:02 -05:00
Dave Chinner 696123fca8 xfs: fix big endian build
Commit 0fd7275cc42ab734eaa1a2c747e65479bd1e42af ("xfs: fix gcc 4.6
set but not read and unused statement warnings") failed to convert
some code inside XFS_NATIVE_HOST (big endian host code only) and
hence fails to build on such machines. Fix it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 16:07:38 -05:00
Christoph Hellwig ecd7f082d6 xfs: clean up xfs_bmap_get_bp
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:53 -05:00
Christoph Hellwig 5d18898b20 xfs: simplify xfs_truncate_file
xfs_truncate_file is only used for truncating quota files.  Move it to
xfs_qm_syscalls.c so it can be marked static and take advatange of the
fact by removing the unused page cache validation and taking the iget
into the helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:52 -05:00
Christoph Hellwig 939d723b72 xfs: kill the b_strat callback in xfs_buf
The b_strat callback is used by xfs_buf_iostrategy to perform additional
checks before submitting a buffer.  It is used in xfs_bwrite and when
writing out delayed buffers.  In xfs_bwrite it we can de-virtualize the
call easily as b_strat is set a few lines above the call to
xfs_buf_iostrategy.  For the delayed buffers the rationale is a bit
more complicated:

 - there are three callers of xfs_buf_delwri_queue, which places buffers
   on the delwri list:
    (1) xfs_bdwrite - this sets up b_strat, so it's fine
    (2) xfs_buf_iorequest.  None of the callers can have XBF_DELWRI set:
	- xlog_bdstrat is only used for log buffers, which are never delwri
	- _xfs_buf_read explicitly clears the delwri flag
	- xfs_buf_iodone_work retries log buffers only
	- xfsbdstrat - only used for reads, superblock writes without the
	  delwri flag, log I/O and file zeroing with explicitly allocated
	  buffers.
	- xfs_buf_iostrategy - only calls xfs_buf_iorequest if b_strat is
	  not set
    (3) xfs_buf_unlock
	- only puts the buffer on the delwri list if the DELWRI flag is
	  already set.  The DELWRI flag is only ever set in xfs_bwrite,
	  xfs_buf_iodone_callbacks, or xfs_trans_log_buf.  For
	  xfs_buf_iodone_callbacks and xfs_trans_log_buf we require
	  an initialized buf item, which means b_strat was set to
	  xfs_bdstrat_cb in xfs_buf_item_init.

Conclusion: we can just get rid of the callback and replace it with
explicit calls to xfs_bdstrat_cb.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:52 -05:00
Christoph Hellwig a64afb057b xfs: remove obsolete osyncisosync mount option
Since Linux 2.6.33 the kernel has support for real O_SYNC, which made
the osyncisosync option a no-op.  Warn the users about this and remove
the mount flag for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:51 -05:00
Christoph Hellwig 0664ce8d0f xfs: clean up filestreams helpers
Move xfs_filestream_peek_ag, xxfs_filestream_get_ag and xfs_filestream_put_ag
from xfs_filestream.h to xfs_filestream.c where it's only callers are, and
remove the inline marker while we're at it to let the compiler decide on the
inlining.  Also don't return a value from xfs_filestream_put_ag because
we don't need it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:51 -05:00
Christoph Hellwig 73523a2ecf xfs: fix gcc 4.6 set but not read and unused statement warnings
[hch: dropped a few hunks that need structural changes instead]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:51 -05:00
Tony Luck 0f1a932f5d xfs: Fix build when CONFIG_XFS_POSIX_ACL=n
When CONFIG_XFS_POSIX_ACL is not set "xfs_check_acl" is #defined
to NULL - which breaks the code attempting to add a tracepoint
on this function.

Only define the tracepoint when the function exists.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:50 -05:00
Kulikov Vasiliy 3f34885cd7 xfs: fix unsigned underflow in xfs_free_eofblocks
map_len is unsigned. Checking map_len <= 0 is buggy when it should be
below zero. So, check exact expression instead of map_len.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:50 -05:00
Dave Chinner aea1b95321 xfs: use GFP_NOFS for page cache allocation
Avoid a lockdep warning by preventing page cache allocation from
recursing back into the filesystem during memory reclaim.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:49 -05:00
Dave Chinner 4a7edddcb5 xfs: fix memory reclaim recursion deadlock on locked inode buffer
Calling into memory reclaim with a locked inode buffer can deadlock
if memory reclaim tries to lock the inode buffer during inode
teardown. Convert the relevant memory allocations to use KM_NOFS to
avoid this deadlock condition.

Reported-by: Peter Watkins <treestem@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:49 -05:00
Dave Chinner 438697064a xfs: fix xfs_trans_add_item() lockdep warnings
xfs_trans_add_item() is called with ip->i_ilock held, which means it
is unsafe for memory reclaim to recurse back into the filesystem
(ilock is required in writeback). Hence the allocation needs to be
KM_NOFS to avoid recursion.

Lockdep report indicating memory allocation being called with the
ip->i_ilock held is as follows:

[ 1749.866796] =================================
[ 1749.867788] [ INFO: inconsistent lock state ]
[ 1749.868327] 2.6.35-rc3-dgc+ #25
[ 1749.868741] ---------------------------------
[ 1749.868741] inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
[ 1749.868741] dd/2835 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 1749.868741]  (&(&ip->i_lock)->mr_lock){++++?.}, at: [<ffffffff813170fb>] xfs_ilock+0x10b/0x190
[ 1749.868741] {IN-RECLAIM_FS-W} state was registered at:
[ 1749.868741]   [<ffffffff810b3a97>] __lock_acquire+0x437/0x1450
[ 1749.868741]   [<ffffffff810b4b56>] lock_acquire+0xa6/0x160
[ 1749.868741]   [<ffffffff810a20b5>] down_write_nested+0x65/0xb0
[ 1749.868741]   [<ffffffff813170fb>] xfs_ilock+0x10b/0x190
[ 1749.868741]   [<ffffffff8134e819>] xfs_reclaim_inode+0x99/0x310
[ 1749.868741]   [<ffffffff8134f56b>] xfs_inode_ag_walk+0x8b/0x150
[ 1749.868741]   [<ffffffff8134f6bb>] xfs_inode_ag_iterator+0x8b/0xf0
[ 1749.868741]   [<ffffffff8134f7a8>] xfs_reclaim_inode_shrink+0x88/0x90
[ 1749.868741]   [<ffffffff81119d07>] shrink_slab+0x137/0x1a0
[ 1749.868741]   [<ffffffff8111bbe1>] balance_pgdat+0x421/0x6a0
[ 1749.868741]   [<ffffffff8111bf7d>] kswapd+0x11d/0x320
[ 1749.868741]   [<ffffffff8109ce56>] kthread+0x96/0xa0
[ 1749.868741]   [<ffffffff81035de4>] kernel_thread_helper+0x4/0x10
[ 1749.868741] irq event stamp: 4234335
[ 1749.868741] hardirqs last  enabled at (4234335): [<ffffffff81147d25>] kmem_cache_free+0x115/0x220
[ 1749.868741] hardirqs last disabled at (4234334): [<ffffffff81147c4d>] kmem_cache_free+0x3d/0x220
[ 1749.868741] softirqs last  enabled at (4233112): [<ffffffff81084dd2>] __do_softirq+0x142/0x260
[ 1749.868741] softirqs last disabled at (4233095): [<ffffffff81035edc>] call_softirq+0x1c/0x50
[ 1749.868741] 
[ 1749.868741] other info that might help us debug this:
[ 1749.868741] 2 locks held by dd/2835:
[ 1749.868741]  #0:  (&(&ip->i_iolock)->mr_lock#2){+.+.+.}, at: [<ffffffff81316edd>] xfs_ilock_nowait+0xed/0x200
[ 1749.868741]  #1:  (&(&ip->i_lock)->mr_lock){++++?.}, at: [<ffffffff813170fb>] xfs_ilock+0x10b/0x190
[ 1749.868741] 
[ 1749.868741] stack backtrace:
[ 1749.868741] Pid: 2835, comm: dd Not tainted 2.6.35-rc3-dgc+ #25
[ 1749.868741] Call Trace:
[ 1749.868741]  [<ffffffff810b1faa>] print_usage_bug+0x18a/0x190
[ 1749.868741]  [<ffffffff8104264f>] ? save_stack_trace+0x2f/0x50
[ 1749.868741]  [<ffffffff810b2400>] ? check_usage_backwards+0x0/0xf0
[ 1749.868741]  [<ffffffff810b2f11>] mark_lock+0x331/0x400
[ 1749.868741]  [<ffffffff810b3047>] mark_held_locks+0x67/0x90
[ 1749.868741]  [<ffffffff810b3111>] lockdep_trace_alloc+0xa1/0xe0
[ 1749.868741]  [<ffffffff81147419>] kmem_cache_alloc+0x39/0x1e0
[ 1749.868741]  [<ffffffff8133f954>] kmem_zone_alloc+0x94/0xe0
[ 1749.868741]  [<ffffffff8133f9be>] kmem_zone_zalloc+0x1e/0x50
[ 1749.868741]  [<ffffffff81335f02>] xfs_trans_add_item+0x72/0xb0
[ 1749.868741]  [<ffffffff81339e41>] xfs_trans_ijoin+0xa1/0xd0
[ 1749.868741]  [<ffffffff81319f82>] xfs_itruncate_finish+0x312/0x5d0
[ 1749.868741]  [<ffffffff8133cb87>] xfs_free_eofblocks+0x227/0x280
[ 1749.868741]  [<ffffffff8133cd18>] xfs_release+0x138/0x190
[ 1749.868741]  [<ffffffff813464c5>] xfs_file_release+0x15/0x20
[ 1749.868741]  [<ffffffff81150ebf>] fput+0x13f/0x260
[ 1749.868741]  [<ffffffff8114d8c2>] filp_close+0x52/0x80
[ 1749.868741]  [<ffffffff8114d9a9>] sys_close+0xb9/0x120
[ 1749.868741]  [<ffffffff81034ff2>] system_call_fastpath+0x16/0x1b

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:49 -05:00
Dave Chinner 2f11feabb1 xfs: simplify and remove xfs_ireclaim
xfs_ireclaim has to get and put te pag structure because it is only
called with the inode to reclaim. The one caller of this function
already has a reference on the pag and a pointer to is, so move the
radix tree delete to the caller and remove xfs_ireclaim completely.
This avoids a xfs_perag_get/put on every inode being reclaimed.

The overhead was noticed in a bug report at:

https://bugzilla.kernel.org/show_bug.cgi?id=16348

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:48 -05:00
Dave Chinner ec53d1dbb3 xfs: don't block on buffer read errors
xfs_buf_read() fails to detect dispatch errors before attempting to
wait on sychronous IO. If there was an error, it will get stuck
forever, waiting for an I/O that was never started. Make sure the
error is detected correctly.

Further, such a failure can leave locked pages in the page cache
which will cause a later operation to hang on the page. Ensure that
we correctly process pages in the buffers when we get a dispatch
error.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:48 -05:00
Dave Chinner a4190f90b4 xfs: move inode shrinker unregister even earlier
I missed Dave Chinner's second revision of this change, and pushed
his first version out to the repository instead.

	commit a476c59ebb279d738718edc0e3fb76aab3687114
	Author: Dave Chinner <dchinner@redhat.com>

This commit compensates for that by moving a block of code up a bit
further, with a result that matches the the effect of Dave's second
version.

Dave's first version was:
	Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Dave's second version was:
	Reviewed-by: Christoph Hellwig <hch@lst.de>

Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2010-07-26 13:16:47 -05:00
Christoph Hellwig fa17b25e9f xfs: remove a dmapi leftover
The open_exec file operation is only added by the external dmapi
patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 13:16:47 -05:00
Christoph Hellwig 78558fe8d8 xfs: writepage always has buffers
These days we always have buffers thanks to ->page_mkwrite.  And we
already have an assert a few lines above tripping in case that was
not true due to a bug.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 13:16:46 -05:00
Christoph Hellwig d4f7a5cbd5 xfs: allow writeback from kswapd
We only need disable I/O from direct or memcg reclaim.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 13:16:46 -05:00
Christoph Hellwig 651701d71d xfs: remove incorrect log write optimization
We do need a barrier for the first buffer of a split log write.
Otherwise we might incorrectly stamp the tail LSN into transactions
in the first part of the split write, or not flush data I/O before
updating the inode size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 13:16:45 -05:00
Dave Chinner 2727ccc950 xfs: unregister inode shrinker before freeing filesystem structures
Currently we don't remove the XFS mount from the shrinker list until
late in the unmount path. By this time, we have already torn down
the internals of the filesystem (e.g. the per-ag structures), and
hence if the shrinker is executed between the teardown and the
unregistering, the shrinker will get NULL per-ag structure pointers
and panic trying to dereference them.

Fix this by removing the xfs mount from the shrinker list before
tearing down it's internal structures.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-07-26 13:16:45 -05:00
Christoph Hellwig cca28fb83d xfs: split xfs_itrace_entry
Replace the xfs_itrace_entry catchall with specific trace points.  For
most simple callers we now use the simple inode class, which used to
be the iget class, but add more details tracing for namespace events,
which now includes the name of the directory entries manipulated.

Remove the xfs_inactive trace point, which is a duplicate of the clear_inode
one, and the xfs_change_file_space trace point, which is immediately
followed by the more specific alloc/free space trace points.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:44 -05:00
Christoph Hellwig f2d6761433 xfs: remove xfs_iput
xfs_iput is just a small wrapper for xfs_iunlock + IRELE.  Having this
out of line wrapper means the trace events in those two can't track
their caller properly.  So just remove the wrapper and opencode the
unlock + rele in the few callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:44 -05:00
Christoph Hellwig ef35e9255d xfs: remove xfs_iput_new
We never get an i_mode of 0 or a locked VFS inode until we pass in the
XFS_IGET_CREATE flag to xfs_iget, which makes xfs_iput_new equivalent to
xfs_iput for the only caller.  In addition to that xfs_nfs_get_inode
does not even need to lock the inode given that the generation never changes
for a life inode, so just pass a 0 lock_flags to xfs_iget and release
the inode using IRELE in the error path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:44 -05:00
Christoph Hellwig d2e078c33c xfs: some iget tracing cleanups / fixes
The xfs_iget_alloc/found tracepoints are a bit misnamed and misplaced.
Rename them to xfs_iget_hit/xfs_iget_miss and move them to the beggining
of the xfs_iget_cache_hit/miss functions.  Add a new xfs_iget_reclaim_fail
tracepoint for the case where we fail to re-initialize a VFS inode,
and add a second instance of the xfs_iget_skip tracepoint for the case
of a failed igrab() call.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:43 -05:00
Christoph Hellwig 807cbbdb43 xfs: do not use emums for flags used in tracing
The tracing code can't print flags defined as enums.  Most flags that
we want to print are defines as macros already, but move the few remaining
ones over to make the trace output more useful.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:43 -05:00
Christoph Hellwig 64c8614941 xfs: remove explicit xfs_sync_data/xfs_sync_attr calls on umount
On the final put of a superblock the VFS already calls sync_filesystem
for us to write out all data and wait for it.  No need to start another
asynchronous writeback inside ->put_super.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:42 -05:00
Christoph Hellwig f2bde9b89b xfs: small cleanups for xfs_iomap / __xfs_get_blocks
Remove the flags argument to  __xfs_get_blocks as we can easily derive
it from the direct argument, and remove the unused BMAPI_MMAP flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:42 -05:00
Christoph Hellwig 3070451eea xfs: reduce stack usage in xfs_iomap
xfs_iomap passes a xfs_bmbt_irec pointer to xfs_iomap_write_direct and
xfs_iomap_write_allocate to give them the results of our read-only
xfs_bmapi query.  Instead of allocating a new xfs_bmbt_irec on stack
for the next call to xfs_bmapi re use the one we got passed as it's not
used after this point.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:42 -05:00
Christoph Hellwig 7a36c8a98a xfs: avoid synchronous transaction in xfs_fs_write_inode
We already rely on the fact that the sync code will cause a synchronous
log force later on (currently via xfs_fs_sync_fs -> xfs_quiesce_data ->
xfs_sync_data), so no need to do this here.  This allows us to avoid
a lot of synchronous log forces during sync, which pays of especially
with delayed logging enabled.   Some compilebench numbers that show
this:

xfs (delayed logging, 256k logbufs)
===================================

intial create		  25.94 MB/s	  25.75 MB/s	  25.64 MB/s
create			   8.54 MB/s	   9.12 MB/s	   9.15 MB/s
patch			   2.47 MB/s	   2.47 MB/s	   3.17 MB/s
compile			  29.65 MB/s	  30.51 MB/s	  27.33 MB/s
clean			  90.92 MB/s	  98.83 MB/s	 128.87 MB/s
read tree		  11.90 MB/s	  11.84 MB/s	   8.56 MB/s
read compiled		  28.75 MB/s	  29.96 MB/s	  24.25 MB/s
delete tree		8.39 seconds	8.12 seconds	8.46 seconds
delete compiled		8.35 seconds	8.44 seconds	5.11 seconds
stat tree		6.03 seconds	5.59 seconds	5.19 seconds
stat compiled tree	9.00 seconds	9.52 seconds	8.49 seconds

xfs + write_inode log_force removal
===================================
intial create		  25.87 MB/s	  25.76 MB/s	  25.87 MB/s
create			  15.18 MB/s	  14.80 MB/s	  14.94 MB/s
patch			   3.13 MB/s	   3.14 MB/s	   3.11 MB/s
compile			  36.74 MB/s	  37.17 MB/s	  36.84 MB/s
clean			 226.02 MB/s	 222.58 MB/s	 217.94 MB/s
read tree		  15.14 MB/s	  15.02 MB/s	  15.14 MB/s
read compiled tree	  29.30 MB/s	  29.31 MB/s	  29.32 MB/s
delete tree		6.22 seconds	6.14 seconds	6.15 seconds
delete compiled tree	5.75 seconds	5.92 seconds	5.81 seconds
stat tree		4.60 seconds	4.51 seconds	4.56 seconds
stat compiled tree	4.07 seconds	3.87 seconds	3.96 seconds

In addition to that also remove the delwri inode flush that is unessecary
now that bulkstat is always coherent.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:41 -05:00
Christoph Hellwig 20cb52ebd1 xfs: simplify xfs_vm_writepage
The writepage implementation in XFS still tries to deal with dirty but
unmapped buffers which used to caused by writes through shared mmaps.  Since
the introduction of ->page_mkwrite these can't happen anymore, so remove the
code dealing with them.

Note that the all_bh variable which causes us to start I/O on all buffers on
the pages was controlled by the count of unmapped buffers, which also
included those not actually dirty.  It's now unconditionally initialized to
0 but set to 1 for the case of small file size extensions.  It probably can
be removed entirely, but that's left for another patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:41 -05:00
Christoph Hellwig 89f3b36396 xfs: simplify xfs_vm_releasepage
Currently the xfs releasepage implementation has code to deal with converting
delayed allocated and unwritten space.  But we never get called for those as
we always convert delayed and unwritten space when cleaning a page, or drop
the state from the buffers in block_invalidatepage.  We still keep a WARN_ON
on those cases for now, but remove all the case dealing with it, which allows
to fold xfs_page_state_convert into xfs_vm_writepage and remove the !startio
case from the whole writeback path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:40 -05:00
Eric Sandeen 3d9b02e3c7 xfs: fix corruption case for block size < page size
xfstests 194 first truncats a file back and then extends it again by
truncating it to a larger size.  This causes discard_buffer to drop
the mapped, but not the uptodate bit and thus creates something that
xfs_page_state_convert takes for unmapped space created by mmap because
it doesn't check for the dirty bit, which also gets cleared by
discard_buffer and checked by other ->writepage implementations like
block_write_full_page.  Handle this kind of buffers early, and unlike
Eric's first version of the patch simply ASSERT that the buffers is
dirty, given that the mmap write case can't happen anymore since the
introduction of ->page_mkwrite.  The now dead code dealing with that
will be deleted in a follow on patch.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:40 -05:00
Christoph Hellwig b4e9181e77 xfs: remove unused delta tracking code in xfs_bmapi
This code was introduced four years ago in commit
3e57ecf640 without any review and has
been unused since.  Remove it just as the rest of the code introduced
in that commit to reduce that stack usage and complexity in this central
piece of code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:39 -05:00
Christoph Hellwig cd8b0bb3c4 xfs: remove unused XFS_BMAPI_ flags
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:39 -05:00
Christoph Hellwig a59f55703c xfs: remove the unused XFS_TRANS_NOSLEEP/XFS_TRANS_WAIT flags
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:38 -05:00
Christoph Hellwig 9134c2332e xfs: remove the unused XFS_LOG_SLEEP and XFS_LOG_NOSLEEP flags
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:38 -05:00
Christoph Hellwig dbb2f6529f xfs: kill the unused xlog_debug variable
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:37 -05:00
Christoph Hellwig 4e0d5f926b xfs: fix the xfs_log_iovec i_addr type
By making this member a void pointer we can get rid of a lot of pointless
casts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:36 -05:00
Christoph Hellwig 898621d5a7 xfs: simplify inode to transaction joining
Currently we need to either call IHOLD or xfs_trans_ihold on an inode when
joining it to a transaction via xfs_trans_ijoin.

This patches instead makes xfs_trans_ijoin usable on it's own by doing
an implicity xfs_trans_ihold, which also allows us to drop the third
argument.  For the case where we want to hold a reference on the inode
a xfs_trans_ijoin_ref wrapper is added which does the IHOLD and marks
the inode for needing an xfs_iput.  In addition to the cleaner interface
to the caller this also simplifies the implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:36 -05:00
Christoph Hellwig 4d16e9246f xfs: simplify buffer pinning
Get rid of the xfs_buf_pin/xfs_buf_unpin/xfs_buf_ispin helpers and opencode
them in their only callers, just like we did for the inode pinning a while
ago.  Also remove duplicate trace points - the bufitem tracepoints cover
all the information that is present in a buffer tracepoint.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:36 -05:00
Christoph Hellwig ca30b2a7b7 xfs: give li_cb callbacks the correct prototype
Stop the function pointer casting madness and give all the li_cb instances
correct prototype.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:35 -05:00
Christoph Hellwig 7bfa31d8e0 xfs: give xfs_item_ops methods the correct prototypes
Stop the function pointer casting madness and give all the xfs_item_ops the
correct prototypes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:35 -05:00
Christoph Hellwig 9412e3181c xfs: merge iop_unpin_remove into iop_unpin
The unpin_remove item operation instances always share most of the
implementation with the respective unpin implementation.  So instead
of keeping two different entry points add a remove flag to the unpin
operation and share the code more easily.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:34 -05:00
Christoph Hellwig e98c414f9a xfs: simplify log item descriptor tracking
Currently we track log item descriptor belonging to a transaction using a
complex opencoded chunk allocator.  This code has been there since day one
and seems to work around the lack of an efficient slab allocator.

This patch replaces it with dynamically allocated log item descriptors
from a dedicated slab pool, linked to the transaction by a linked list.

This allows to greatly simplify the log item descriptor tracking to the
point where it's just a couple hundred lines in xfs_trans.c instead of
a separate file.  The external API has also been simplified while we're
at it - the xfs_trans_add_item and xfs_trans_del_item functions to add/
delete items from a transaction have been simplified to the bare minium,
and the xfs_trans_find_item function is replaced with a direct dereference
of the li_desc field.  All debug code walking the list of log items in
a transaction is down to a simple list_for_each_entry.

Note that we could easily use a singly linked list here instead of the
double linked list from list.h as the fastpath only does deletion from
sequential traversal.  But given that we don't have one available as
a library function yet I use the list.h functions for simplicity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:34 -05:00
Christoph Hellwig 3400777ff0 xfs: remove unneeded #include statements
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
2010-07-26 13:16:33 -05:00
Christoph Hellwig 288699feca xfs: drop dmapi hooks
Dmapi support was never merged upstream, but we still have a lot of hooks
bloating XFS for it, all over the fast pathes of the filesystem.

This patch drops over 700 lines of dmapi overhead.  If we'll ever get HSM
support in mainline at least the namespace events can be done much saner
in the VFS instead of the individual filesystem, so it's not like this
is much help for future work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:33 -05:00
Christoph Hellwig ade7ce31c2 quota: Clean up the namespace in dqblk_xfs.h
Almost all identifiers use the FS_* namespace, so rename the missing few
XFS_* ones to FS_* as well.  Without this some people might get upset
about having too many XFS names in generic code.

Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2010-07-21 16:01:46 +02:00
Dave Chinner 16fd536737 xfs: track AGs with reclaimable inodes in per-ag radix tree
https://bugzilla.kernel.org/show_bug.cgi?id=16348

When the filesystem grows to a large number of allocation groups,
the summing of recalimable inodes gets expensive. In many cases,
most AGs won't have any reclaimable inodes and so we are wasting CPU
time aggregating over these AGs. This is particularly important for
the inode shrinker that gets called frequently under memory
pressure.

To avoid the overhead, track AGs with reclaimable inodes in the
per-ag radix tree so that we can find all the AGs with reclaimable
inodes via a simple gang tag lookup. This involves setting the tag
when the first reclaimable inode is tracked in the AG, and removing
the tag when the last reclaimable inode is removed from the tree.
Then the summation process becomes a loop walking the radix tree
summing AGs with the reclaim tag set.

This significantly reduces the overhead of scanning - a 6400 AG
filesystea now only uses about 25% of a cpu in kswapd while slab
reclaim progresses instead of being permanently stuck at 100% CPU
and making little progress. Clean filesystems filesystems will see
no overhead and the overhead only increases linearly with the number
of dirty AGs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-07-20 09:43:39 +10:00
Dave Chinner 70e60ce715 xfs: convert inode shrinker to per-filesystem contexts
Now the shrinker passes us a context, wire up a shrinker context per
filesystem. This allows us to remove the global mount list and the
locking problems that introduced. It also means that a shrinker call
does not need to traverse clean filesystems before finding a
filesystem with reclaimable inodes.  This significantly reduces
scanning overhead when lots of filesystems are present.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-07-20 08:07:02 +10:00
Dave Chinner 7f8275d0d6 mm: add context argument to shrinker callback
The current shrinker implementation requires the registered callback
to have global state to work from. This makes it difficult to shrink
caches that are not global (e.g. per-filesystem caches). Pass the shrinker
structure to the callback so that users can embed the shrinker structure
in the context the shrinker needs to operate on and get back to it in the
callback via container_of().

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-07-19 14:56:17 +10:00
Dave Chinner 7b6259e7a8 xfs: remove block number from inode lookup code
The block number comes from bulkstat based inode lookups to shortcut
the mapping calculations. We ar enot able to trust anything from
bulkstat, so drop the block number as well so that the correct
lookups and mappings are always done.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-06-24 11:35:17 +10:00
Dave Chinner 1920779e67 xfs: rename XFS_IGET_BULKSTAT to XFS_IGET_UNTRUSTED
Inode numbers may come from somewhere external to the filesystem
(e.g. file handles, bulkstat information) and so are inherently
untrusted. Rename the flag we use for these lookups to make it
obvious we are doing a lookup of an untrusted inode number and need
to verify it completely before trying to read it from disk.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-06-24 11:15:47 +10:00
Dave Chinner 7124fe0a5b xfs: validate untrusted inode numbers during lookup
When we decode a handle or do a bulkstat lookup, we are using an
inode number we cannot trust to be valid. If we are deleting inode
chunks from disk (default noikeep mode), then we cannot trust the on
disk inode buffer for any given inode number to correctly reflect
whether the inode has been unlinked as the di_mode nor the
generation number may have been updated on disk.

This is due to the fact that when we delete an inode chunk, we do
not write the clusters back to disk when they are removed - instead
we mark them stale to avoid them being written back potentially over
the top of something that has been subsequently allocated at that
location. The result is that we can have locations of disk that look
like they contain valid inodes but in reality do not. Hence we
cannot simply convert the inode number to a block number and read
the location from disk to determine if the inode is valid or not.

As a result, and XFS_IGET_BULKSTAT lookup needs to actually look the
inode up in the inode allocation btree to determine if the inode
number is valid or not.

It should be noted even on ikeep filesystems, there is the
possibility that blocks on disk may look like valid inode clusters.
e.g. if there are filesystem images hosted on the filesystem. Hence
even for ikeep filesystems we really need to validate that the inode
number is valid before issuing the inode buffer read.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-06-24 11:15:33 +10:00
Christoph Hellwig 7dce11dbac xfs: always use iget in bulkstat
The non-coherent bulkstat versionsthat look directly at the inode
buffers causes various problems with performance optimizations that
make increased use of just logging inodes.  This patch makes bulkstat
always use iget, which should be fast enough for normal use with the
radix-tree based inode cache introduced a while ago.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-06-23 18:11:11 +10:00
Dan Rosenberg 1817176a86 xfs: prevent swapext from operating on write-only files
This patch prevents user "foo" from using the SWAPEXT ioctl to swap
a write-only file owned by user "bar" into a file owned by "foo" and
subsequently reading it.  It does so by checking that the file
descriptors passed to the ioctl are also opened for reading.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-06-24 12:07:47 +10:00
Dave Chinner 254c8c2dbf xfs: remove nr_to_write writeback windup.
Now that the background flush code has been fixed, we shouldn't need to
silently multiply the wbc->nr_to_write to get good writeback. Remove
that code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-08 18:12:44 -07:00
Alex Elder 1bf7dbfde8 Merge branch 'master' into for-linus 2010-06-04 13:22:30 -05:00
Christoph Hellwig f936972949 xfs: improve xfs_isilocked
Use rwsem_is_locked to make the assertations for shared locks work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-06-03 16:22:29 +10:00
Christoph Hellwig 070ecdca54 xfs: skip writeback from reclaim context
Allowing writeback from reclaim context causes massive problems with stack
overflows as we can call into the writeback code which tends to be a heavy
stack user both in the generic code and XFS from random contexts that
perform memory allocations.

Follow the example of btrfs (and in slightly different form ext4) and refuse
to write out data from reclaim context.  This issue should really be handled
by the VM so that we can tune better for this case, but until we get it
sorted out there we have to hack around this in each filesystem with a
complex writeback path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-06-03 16:22:29 +10:00
Dave Chinner 5b257b4a1f xfs: fix race in inode cluster freeing failing to stale inodes
When an inode cluster is freed, it needs to mark all inodes in memory as
XFS_ISTALE before marking the buffer as stale. This is eeded because the inodes
have a different life cycle to the buffer, and once the buffer is torn down
during transaction completion, we must ensure none of the inodes get written
back (which is what XFS_ISTALE does).

Unfortunately, xfs_ifree_cluster() has some bugs that lead to inodes not being
marked with XFS_ISTALE. This shows up when xfs_iflush() is called on these
inodes either during inode reclaim or tail pushing on the AIL.  The buffer is
read back, but no longer contains inodes and so triggers assert failures and
shutdowns. This was reproducable with at run.dbench10 invocation from xfstests.

There are two main causes of xfs_ifree_cluster() failing. The first is simple -
it checks in-memory inodes it finds in the per-ag icache to see if they are
clean without holding the flush lock. if they are clean it skips them
completely. However, If an inode is flushed delwri, it will
appear clean, but is not guaranteed to be written back until the flush lock has
been dropped. Hence we may have raced on the clean check and the inode may
actually be dirty. Hence always mark inodes found in memory stale before we
check properly if they are clean.

The second is more complex, and makes the first problem easier to hit.
Basically the in-memory inode scan is done with full knowledge it can be racing
with inode flushing and AIl tail pushing, which means that inodes that it can't
get the flush lock on might not be attached to the buffer after then in-memory
inode scan due to IO completion occurring. This is actually documented in the
code as "needs better interlocking". i.e. this is a zero-day bug.

Effectively, the in-memory scan must be done while the inode buffer is locked
and Io cannot be issued on it while we do the in-memory inode scan. This
ensures that inodes we couldn't get the flush lock on are guaranteed to be
attached to the cluster buffer, so we can then catch all in-memory inodes and
mark them stale.

Now that the inode cluster buffer is locked before the in-memory scan is done,
there is no need for the two-phase update of the in-memory inodes, so simplify
the code into two loops and remove the allocation of the temporary buffer used
to hold locked inodes across the phases.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2010-06-03 16:22:29 +10:00
Christoph Hellwig fb3b504ade xfs: fix access to upper inodes without inode64
If a filesystem is mounted without the inode64 mount option we
should still be able to access inodes not fitting into 32 bits, just
not created new ones.  For this to work we need to make sure the
inode cache radix tree is initialized for all allocation groups, not
just those we plan to allocate inodes from.  This patch makes sure
we initialize the inode cache radix tree for all allocation groups,
and also cleans xfs_initialize_perag up a bit to separate the
inode32 logical from the general perag structure setup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:56 -05:00
Dave Chinner 9b98b6f3e1 xfs: fix might_sleep() warning when initialising per-ag tree
The use of radix_tree_preload() only works if the radix tree was
initialised without the __GFP_WAIT flag. The per-ag tree uses
GFP_NOFS, so does not trigger allocation of new tree nodes from the
preloaded array. Hence it enters the allocator with a spinlock held
and triggers the might_sleep() warnings.

Reported-by; Chris Mason <chris.mason@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:50 -05:00
Julia Lawall 38e712ab3d fs/xfs/quota: Add missing mutex_unlock
Add a mutex_unlock missing on the error path.  The use of this lock
is balanced elsewhere in the file.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* mutex_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* mutex_unlock(E1,...);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:41 -05:00
Huang Weiyi 3bd0946eb1 xfs: remove duplicated #include
Remove duplicated #include('s) in
  fs/xfs/linux-2.6/xfs_quotaops.c

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:36 -05:00
Li Zefan f8adb4d574 xfs: convert more trace events to DEFINE_EVENT
Use DECLARE_EVENT_CLASS, and save ~15K:

   text    data     bss     dec     hex filename
 171949   43028      48  215025   347f1 fs/xfs/linux-2.6/xfs_trace.o.orig
 156521   43028      36  199585   30ba1 fs/xfs/linux-2.6/xfs_trace.o

No change in functionality.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:31 -05:00
Huang Weiyi 292ec4cf35 xfs: xfs_trace.c: remove duplicated #include
Remove duplicated #include('s) in
  fs/xfs/linux-2.6/xfs_trace.c

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:24 -05:00
Dave Chinner 07f1a4f5e8 xfs: Check new inode size is OK before preallocating
The new xfsqa test 228 tries to preallocate more space than the
filesystem contains. it should fail, but instead triggers an assert
about lock flags.  The failure is due to the size extension failing
in vmtruncate() due to rlimit being set. Check this before we start
the preallocation to avoid allocating space that will never be used.

Also the path through xfs_vn_allocate already holds the IO lock, so
it should not be present in the lock flags when the setattr fails.
Hence the assert needs to take this into account. This will prevent
other such callers from hitting this incorrect ASSERT.

(Fixed a reference to "newsize" to read "new_size". -Alex)

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 15:19:12 -05:00
Christoph Hellwig fdc07f44c8 xfs: clean up xlog_align
Add suggested cleanups to commit 29db3370a1369541d58d692fbfb168b8a0bd7f41
from review that didn't end up being commited.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 14:58:36 -05:00
Christoph Hellwig 025101dca4 xfs: cleanup log reservation calculactions
Instead of having small helper functions calling big macros do the
calculations for the log reservations directly in the functions.
These are mostly 1:1 from the macros execept that the macros kept
the quota calculations in their callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 14:58:30 -05:00
Eric Sandeen 32891b292d xfs: be more explicit if RT mount fails due to config
Recent testers were slightly confused that a realtime mount failed
due to missing CONFIG_XFS_RT; we can make that a little more
obvious.

V2: drop the else as suggested by Christoph

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 14:58:24 -05:00
Eric Sandeen 657a4cffde xfs: replace E2BIG with EFBIG where appropriate
Many places in the xfs code return E2BIG when they really mean
EFBIG; trying to grow past 16T on a 32 bit machine, for example,
says "Argument list too long" rather than "File too large" which is
not particularly helpful.

Some of these don't make perfect sense as EFBIG either, but still
better than E2BIG IMHO.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-05-28 14:58:16 -05:00