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path: root/fs/xfs/xfs_log_recover.c
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2015-02-13Reset to 3.12.37Scott Wood
2013-10-04xfs: Use kmem_free() instead of free()Thierry Reding
This fixes a build failure caused by calling the free() function which does not exist in the Linux kernel. Signed-off-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com> (cherry picked from commit aaaae98022efa4f3c31042f1fdf9e7a0c5f04663)
2013-10-04xfs: fix memory leak in xlog_recover_add_to_transtinguely@sgi.com
Free the memory in error path of xlog_recover_add_to_trans(). Normally this memory is freed in recovery pass2, but is leaked in the error path. Signed-off-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com> (cherry picked from commit 519ccb81ac1c8e3e4eed294acf93be00b43dcad6)
2013-09-24xfs: log recovery lsn ordering needs uuid checkDave Chinner
After a fair number of xfstests runs, xfs/182 started to fail regularly with a corrupted directory - a directory read verifier was failing after recovery because it found a block with a XARM magic number (remote attribute block) rather than a directory data block. The first time I saw this repeated failure I did /something/ and the problem went away, so I was never able to find the underlying problem. Test xfs/182 failed again today, and I found the root cause before I did /something else/ that made it go away. Tracing indicated that the block in question was being correctly logged, the log was being flushed by sync, but the buffer was not being written back before the shutdown occurred. Tracing also indicated that log recovery was also reading the block, but then never writing it before log recovery invalidated the cache, indicating that it was not modified by log recovery. More detailed analysis of the corpse indicated that the filesystem had a uuid of "a4131074-1872-4cac-9323-2229adbcb886" but the XARM block had a uuid of "8f32f043-c3c9-e7f8-f947-4e7f989c05d3", which indicated it was a block from an older filesystem. The reason that log recovery didn't replay it was that the LSN in the XARM block was larger than the LSN of the transaction being replayed, and so the block was not overwritten by log recovery. Hence, log recovery cant blindly trust the magic number and LSN in the block - it must verify that it belongs to the filesystem being recovered before using the LSN. i.e. if the UUIDs don't match, we need to unconditionally recovery the change held in the log. This patch was first tested on a block device that was repeatedly causing xfs/182 to fail with the same failure on the same block with the same directory read corruption signature (i.e. XARM block). It did not fail, and hasn't failed since. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-09-12xfs: remove dead code from xlog_recover_inode_pass2Mark Tinguely
Additional code in the error handler of xlog_recover_inode_pass2() results in the following error: static checker warning: "fs/xfs/xfs_log_recover.c:2999 xlog_recover_inode_pass2() info: ignoring unreachable code." Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mark Tinguely <tinguely@sgi.com> Reviewed-by: Ben Myers <bpm@sgi.com Signed-off-by: Ben Myers <bpm@sgi.com>
2013-09-10xfs: recovery of swap extents operations for CRC filesystemsDave Chinner
This is the recovery side of the btree block owner change operation performed by swapext on CRC enabled filesystems. We detect that an owner change is needed by the flag that has been placed on the inode log format flag field. Because the inode recovery is being replayed after the buffers that make up the BMBT in the given checkpoint, we can walk all the buffers and directly modify them when we see the flag set on an inode. Because the inode can be relogged and hence present in multiple chekpoints with the "change owner" flag set, we could do multiple passes across the inode to do this change. While this isn't optimal, we can't directly ignore the flag as there may be multiple independent swap extent operations being replayed on the same inode in different checkpoints so we can't ignore them. Further, because the owner change operation uses ordered buffers, we might have buffers that are newer on disk than the current checkpoint and so already have the owner changed in them. Hence we cannot just peek at a buffer in the tree and check that it has the correct owner and assume that the change was completed. So, for the moment just brute force the owner change every time we see an inode with the flag set. Note that we have to be careful here because the owner of the buffers may point to either the old owner or the new owner. Currently the verifier can't verify the owner directly, so there is no failure case here right now. If we verify the owner exactly in future, then we'll have to take this into account. This was tested in terms of normal operation via xfstests - all of the fsr tests now pass without failure. however, we really need to modify xfs/227 to stress v3 inodes correctly to ensure we fully cover this case for v5 filesystems. In terms of recovery testing, I used a hacked version of xfs_fsr that held the temp inode open for a few seconds before exiting so that the filesystem could be shut down with an open owner change recovery flags set on at least the temp inode. fsr leaves the temp inode unlinked and in btree format, so this was necessary for the owner change to be reliably replayed. logprint confirmed the tmp inode in the log had the correct flag set: INO: cnt:3 total:3 a:0x69e9e0 len:56 a:0x69ea20 len:176 a:0x69eae0 len:88 INODE: #regs:3 ino:0x44 flags:0x209 dsize:88 ^^^^^ 0x200 is set, indicating a data fork owner change needed to be replayed on inode 0x44. A printk in the revoery code confirmed that the inode change was recovered: XFS (vdc): Mounting Filesystem XFS (vdc): Starting recovery (logdev: internal) recovering owner change ino 0x44 XFS (vdc): Version 5 superblock detected. This kernel L support enabled! Use of these features in this kernel is at your own risk! XFS (vdc): Ending recovery (logdev: internal) The script used to test this was: $ cat ./recovery-fsr.sh #!/bin/bash dev=/dev/vdc mntpt=/mnt/scratch testfile=$mntpt/testfile umount $mntpt mkfs.xfs -f -m crc=1 $dev mount $dev $mntpt chmod 777 $mntpt for i in `seq 10000 -1 0`; do xfs_io -f -d -c "pwrite $(($i * 4096)) 4096" $testfile > /dev/null 2>&1 done xfs_bmap -vp $testfile |head -20 xfs_fsr -d -v $testfile & sleep 10 /home/dave/src/xfstests-dev/src/godown -f $mntpt wait umount $mntpt xfs_logprint -t $dev |tail -20 time mount $dev $mntpt xfs_bmap -vp $testfile umount $mntpt $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-09-09xfs: fix endian warning in xlog_recover_get_buf_lsn()Dave Chinner
sparse reports: fs/xfs/xfs_log_recover.c:2017:24: sparse: cast to restricted __be64 Because I used the wrong structure for the on-disk superblock cast in 50d5c8d ("xfs: check LSN ordering for v5 superblocks during recovery"). Fix it. Reported-by: kbuild test robot Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-30xfs: inode buffers may not be valid during recovery readaheadDave Chinner
CRC enabled filesystems fail log recovery with 100% reliability on xfstests xfs/085 with the following failure: XFS (vdb): Mounting Filesystem XFS (vdb): Starting recovery (logdev: internal) XFS (vdb): Corruption detected. Unmount and run xfs_repair XFS (vdb): bad inode magic/vsn daddr 144 #0 (magic=0) XFS: Assertion failed: 0, file: fs/xfs/xfs_inode_buf.c, line: 95 The problem is that the inode buffer has not been recovered before the readahead on the inode buffer is issued. The checkpoint being recovered actually allocates the inode chunk we are doing readahead from, so what comes from disk during readahead is essentially random and the verifier barfs on it. This inode buffer readahead problem affects non-crc filesystems, too, but xfstests does not trigger it at all on such configurations.... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-30xfs: check LSN ordering for v5 superblocks during recoveryDave Chinner
Log recovery has some strict ordering requirements which unordered or reordered metadata writeback can defeat. This can occur when an item is logged in a transaction, written back to disk, and then logged in a new transaction before the tail of the log is moved past the original modification. The result of this is that when we read an object off disk for recovery purposes, the buffer that we read may not contain the object type that recovery is expecting and hence at the end of the checkpoint being recovered we have an invalid object in memory. This isn't usually a problem, as recovery will then replay all the other checkpoints and that brings the object back to a valid and correct state, but the issue is that while the object is in the invalid state it can be flushed to disk. This results in the object verifier failing and triggering a corruption shutdown of log recover. This is correct behaviour for the verifiers - the problem is that we are not detecting that the object we've read off disk is newer than the transaction we are replaying. All metadata in v5 filesystems has the LSN of it's last modification stamped in it. This enabled log recover to read that field and determine the age of the object on disk correctly. If the LSN of the object on disk is older than the transaction being replayed, then we replay the modification. If the LSN of the object matches or is more recent than the transaction's LSN, then we should avoid overwriting the object as that is what leads to the transient corrupt state. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-29xfs: fix bad dquot buffer size in log recovery readaheadDave Chinner
xfstests xfs/087 fails 100% reliably with this assert: XFS (vdb): Mounting Filesystem XFS (vdb): Starting recovery (logdev: internal) XFS: Assertion failed: bp->b_flags & XBF_STALE, file: fs/xfs/xfs_buf.c, line: 548 while trying to read a dquot buffer in xlog_recover_dquot_ra_pass2(). The issue is that the buffer length to read that is passed to xfs_buf_readahead is in units of filesystem blocks, not disk blocks. (i.e. FSB, not daddr). Fix it but putting the correct conversion in place. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-29xfs: don't account buffer cancellation during log recovery readaheadDave Chinner
When doing readhaead in log recovery, we check to see if buffers are cancelled before doing readahead. If we find a cancelled buffer, however, we always decrement the reference count we have on it, and that means that readahead is causing a double decrement of the cancelled buffer reference count. This results in log recovery *replaying cancelled buffers* as the actual recovery pass does not find the cancelled buffer entry in the commit phase of the second pass across a transaction. On debug kernels, this results in an ASSERT failure like so: XFS: Assertion failed: !(flags & XFS_BLF_CANCEL), file: fs/xfs/xfs_log_recover.c, line: 1815 xfstests generic/311 reproduces this ASSERT failure with 100% reproducability. Fix it by making readahead only peek at the buffer cancelled state rather than the full accounting that xlog_check_buffer_cancelled() does. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-23xfs: introduce object readahead to log recoveryZhi Yong Wu
It can take a long time to run log recovery operation because it is single threaded and is bound by read latency. We can find that it took most of the time to wait for the read IO to occur, so if one object readahead is introduced to log recovery, it will obviously reduce the log recovery time. Log recovery time stat: w/o this patch w/ this patch real: 0m15.023s 0m7.802s user: 0m0.001s 0m0.001s sys: 0m0.246s 0m0.107s Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-20xfs: fix the comment of xlog_recover_do_dquot_buffer()Zhi Yong Wu
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-20xfs: fix the comment of xlog_find_head()Zhi Yong Wu
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-20xfs: fix the comment of xlog_recover_buffer_pass2()Zhi Yong Wu
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-13xfs:free bp in xlog_find_tail() error pathEric Sandeen
xlog_find_tail() currently leaks a bp on one error path. There is no error target, so manually free the bp before returning the error. Found by Coverity. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-13xfs: free bp in xlog_find_zeroed() error pathEric Sandeen
xlog_find_zeroed() currently leaks a bp on one error path. Using the bp_err: target resolves this. Found by Coverity. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12xfs: refactor xfs_trans_reserve() interfaceJie Liu
With the new xfs_trans_res structure has been introduced, the log reservation size, log count as well as log flags are pre-initialized at mount time. So it's time to refine xfs_trans_reserve() interface to be more neat. Also, introduce a new helper M_RES() to return a pointer to the mp->m_resv structure to simplify the input. Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12xfs: consolidate xfs_utils.cDave Chinner
There are a few small helper functions in xfs_util, all related to xfs_inode modifications. Move them all to xfs_inode.c so all xfs_inode operations are consiolidated in the one place. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12xfs: reshuffle dir2 definitions around for userspaceDave Chinner
Many of the definitions within xfs_dir2_priv.h are needed in userspace outside libxfs. Definitions within xfs_dir2_priv.h are wholly contained within libxfs, so we need to shuffle some of the definitions around to keep consistency across files shared between user and kernel space. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12xfs: separate dquot on disk format definitions out of xfs_quota.hDave Chinner
The on disk format definitions of the on-disk dquot, log formats and quota off log formats are all intertwined with other definitions for quotas. Separate them out into their own header file so they can easily be shared with userspace. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-08-12xfs: separate out log format definitionsDave Chinner
The on-disk format definitions for the log are spread randoms through a couple of header files. Consolidate it all in a single file that can be shared easily with userspace. This means that xfs_log.h and xfs_log_priv.h no longer need to be shared with userspace. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-07-24xfs: di_flushiter considered harmfulDave Chinner
When we made all inode updates transactional, we no longer needed the log recovery detection for inodes being newer on disk than the transaction being replayed - it was redundant as replay of the log would always result in the latest version of the inode would be on disk. It was redundant, but left in place because it wasn't considered to be a problem. However, with the new "don't read inodes on create" optimisation, flushiter has come back to bite us. Essentially, the optimisation made always initialises flushiter to zero in the create transaction, and so if we then crash and run recovery and the inode already on disk has a non-zero flushiter it will skip recovery of that inode. As a result, log recovery does the wrong thing and we end up with a corrupt filesystem. Because we have to support old kernel to new kernel upgrades, we can't just get rid of the flushiter support in log recovery as we might be upgrading from a kernel that doesn't have fully transactional inode updates. Unfortunately, for v4 superblocks there is no way to guarantee that log recovery knows about this fact. We cannot add a new inode format flag to say it's a "special inode create" because it won't be understood by older kernels and so recovery could do the wrong thing on downgrade. We cannot specially detect the combination of zero mode/non-zero flushiter on disk to non-zero mode, zero flushiter in the log item during recovery because wrapping of the flushiter can result in false detection. Hence that makes this "don't use flushiter" optimisation limited to a disk format that guarantees that we don't need it. And that means the only fix here is to limit the "no read IO on create" optimisation to version 5 superblocks.... Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-27xfs: Inode create item recoveryDave Chinner
When we find a icreate transaction, we need to get and initialise the buffers in the range that has been passed. Extract and verify the information in the item record, then loop over the range initialising and issuing the buffer writes delayed. Support an arbitrary size range to initialise so that in future when we allocate inodes in much larger chunks all kernels that understand this transaction can still recover them. Signed-off-by: Dave Chinner <david@fromorbit.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-14xfs: don't shutdown log recovery on validation errorsDave Chinner
Unfortunately, we cannot guarantee that items logged multiple times and replayed by log recovery do not take objects back in time. When they are taken back in time, the go into an intermediate state which is corrupt, and hence verification that occurs on this intermediate state causes log recovery to abort with a corruption shutdown. Instead of causing a shutdown and unmountable filesystem, don't verify post-recovery items before they are written to disk. This is less than optimal, but there is no way to detect this issue for non-CRC filesystems If log recovery successfully completes, this will be undone and the object will be consistent by subsequent transactions that are replayed, so in most cases we don't need to take drastic action. For CRC enabled filesystems, leave the verifiers in place - we need to call them to recalculate the CRCs on the objects anyway. This recovery problem can be solved for such filesystems - we have a LSN stamped in all metadata at writeback time that we can to determine whether the item should be replayed or not. This is a separate piece of work, so is not addressed by this patch. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-05xfs: inode unlinked list needs to recalculate the inode CRCDave Chinner
The inode unlinked list manipulations operate directly on the inode buffer, and so bypass the inode CRC calculation mechanisms. Hence an inode on the unlinked list has an invalid CRC. Fix this by recalculating the CRC whenever we modify an unlinked list pointer in an inode, ncluding during log recovery. This is trivial to do and results in unlinked list operations always leaving a consistent inode in the buffer. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-05xfs: fix log recovery transaction item reorderingDave Chinner
There are several constraints that inode allocation and unlink logging impose on log recovery. These all stem from the fact that inode alloc/unlink are logged in buffers, but all other inode changes are logged in inode items. Hence there are ordering constraints that recovery must follow to ensure the correct result occurs. As it turns out, this ordering has been working mostly by chance than good management. The existing code moves all buffers except cancelled buffers to the head of the list, and everything else to the tail of the list. The problem with this is that is interleaves inode items with the buffer cancellation items, and hence whether the inode item in an cancelled buffer gets replayed is essentially left to chance. Further, this ordering causes problems for log recovery when inode CRCs are enabled. It typically replays the inode unlink buffer long before it replays the inode core changes, and so the CRC recorded in an unlink buffer is going to be invalid and hence any attempt to validate the inode in the buffer is going to fail. Hence we really need to enforce the ordering that the inode alloc/unlink code has expected log recovery to have since inode chunk de-allocation was introduced back in 2003... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-06-04xfs: rework dquot CRCsDave Chinner
Calculating dquot CRCs when the backing buffer is written back just doesn't work reliably. There are several places which manipulate dquots directly in the buffers, and they don't calculate CRCs appropriately, nor do they always set the buffer up to calculate CRCs appropriately. Firstly, if we log a dquot buffer (e.g. during allocation) it gets logged without valid CRC, and so on recovery we end up with a dquot that is not valid. Secondly, if we recover/repair a dquot, we don't have a verifier attached to the buffer and hence CRCs are not calculated on the way down to disk. Thirdly, calculating the CRC after we've changed the contents means that if we re-read the dquot from the buffer, we cannot verify the contents of the dquot are valid, as the CRC is invalid. So, to avoid all the dquot CRC errors that are being detected by the read verifier, change to using the same model as for inodes. That is, dquot CRCs are calculated and written to the backing buffer at the time the dquot is flushed to the backing buffer. If we modify the dquot directly in the backing buffer, calculate the CRC immediately after the modification is complete. Hence the dquot in the on-disk buffer should always have a valid CRC. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-30xfs: fix split buffer vector log recovery supportDave Chinner
A long time ago in a galaxy far away.... .. the was a commit made to fix some ilinux specific "fragmented buffer" log recovery problem: http://oss.sgi.com/cgi-bin/gitweb.cgi?p=archive/xfs-import.git;a=commitdiff;h=b29c0bece51da72fb3ff3b61391a391ea54e1603 That problem occurred when a contiguous dirty region of a buffer was split across across two pages of an unmapped buffer. It's been a long time since that has been done in XFS, and the changes to log the entire inode buffers for CRC enabled filesystems has re-introduced that corner case. And, of course, it turns out that the above commit didn't actually fix anything - it just ensured that log recovery is guaranteed to fail when this situation occurs. And now for the gory details. xfstest xfs/085 is failing with this assert: XFS (vdb): bad number of regions (0) in inode log format XFS: Assertion failed: 0, file: fs/xfs/xfs_log_recover.c, line: 1583 Largely undocumented factoid #1: Log recovery depends on all log buffer format items starting with this format: struct foo_log_format { __uint16_t type; __uint16_t size; .... As recoery uses the size field and assumptions about 32 bit alignment in decoding format items. So don't pay much attention to the fact log recovery thinks that it decoding an inode log format item - it just uses them to determine what the size of the item is. But why would it see a log format item with a zero size? Well, luckily enough xfs_logprint uses the same code and gives the same error, so with a bit of gdb magic, it turns out that it isn't a log format that is being decoded. What logprint tells us is this: Oper (130): tid: a0375e1a len: 28 clientid: TRANS flags: none BUF: #regs: 2 start blkno: 144 (0x90) len: 16 bmap size: 2 flags: 0x4000 Oper (131): tid: a0375e1a len: 4096 clientid: TRANS flags: none BUF DATA ---------------------------------------------------------------------------- Oper (132): tid: a0375e1a len: 4096 clientid: TRANS flags: none xfs_logprint: unknown log operation type (4e49) ********************************************************************** * ERROR: data block=2 * ********************************************************************** That we've got a buffer format item (oper 130) that has two regions; the format item itself and one dirty region. The subsequent region after the buffer format item and it's data is them what we are tripping over, and the first bytes of it at an inode magic number. Not a log opheader like there is supposed to be. That means there's a problem with the buffer format item. It's dirty data region is 4096 bytes, and it contains - you guessed it - initialised inodes. But inode buffers are 8k, not 4k, and we log them in their entirety. So something is wrong here. The buffer format item contains: (gdb) p /x *(struct xfs_buf_log_format *)in_f $22 = {blf_type = 0x123c, blf_size = 0x2, blf_flags = 0x4000, blf_len = 0x10, blf_blkno = 0x90, blf_map_size = 0x2, blf_data_map = {0xffffffff, 0xffffffff, .... }} Two regions, and a signle dirty contiguous region of 64 bits. 64 * 128 = 8k, so this should be followed by a single 8k region of data. And the blf_flags tell us that the type of buffer is a XFS_BLFT_DINO_BUF. It contains inodes. And because it doesn't have the XFS_BLF_INODE_BUF flag set, that means it's an inode allocation buffer. So, it should be followed by 8k of inode data. But we know that the next region has a header of: (gdb) p /x *ohead $25 = {oh_tid = 0x1a5e37a0, oh_len = 0x100000, oh_clientid = 0x69, oh_flags = 0x0, oh_res2 = 0x0} and so be32_to_cpu(oh_len) = 0x1000 = 4096 bytes. It's simply not long enough to hold all the logged data. There must be another region. There is - there's a following opheader for another 4k of data that contains the other half of the inode cluster data - the one we assert fail on because it's not a log format header. So why is the second part of the data not being accounted to the correct buffer log format structure? It took a little more work with gdb to work out that the buffer log format structure was both expecting it to be there but hadn't accounted for it. It was at that point I went to the kernel code, as clearly this wasn't a bug in xfs_logprint and the kernel was writing bad stuff to the log. First port of call was the buffer item formatting code, and the discontiguous memory/contiguous dirty region handling code immediately stood out. I've wondered for a long time why the code had this comment in it: vecp->i_addr = xfs_buf_offset(bp, buffer_offset); vecp->i_len = nbits * XFS_BLF_CHUNK; vecp->i_type = XLOG_REG_TYPE_BCHUNK; /* * You would think we need to bump the nvecs here too, but we do not * this number is used by recovery, and it gets confused by the boundary * split here * nvecs++; */ vecp++; And it didn't account for the extra vector pointer. The case being handled here is that a contiguous dirty region lies across a boundary that cannot be memcpy()d across, and so has to be split into two separate operations for xlog_write() to perform. What this code assumes is that what is written to the log is two consecutive blocks of data that are accounted in the buf log format item as the same contiguous dirty region and so will get decoded as such by the log recovery code. The thing is, xlog_write() knows nothing about this, and so just does it's normal thing of adding an opheader for each vector. That means the 8k region gets written to the log as two separate regions of 4k each, but because nvecs has not been incremented, the buf log format item accounts for only one of them. Hence when we come to log recovery, we process the first 4k region and then expect to come across a new item that starts with a log format structure of some kind that tells us whenteh next data is going to be. Instead, we hit raw buffer data and things go bad real quick. So, the commit from 2002 that commented out nvecs++ is just plain wrong. It breaks log recovery completely, and it would seem the only reason this hasn't been since then is that we don't log large contigous regions of multi-page unmapped buffers very often. Never would be a closer estimate, at least until the CRC code came along.... So, lets fix that by restoring the nvecs accounting for the extra region when we hit this case..... .... and there's the problemin log recovery it is apparently working around: XFS: Assertion failed: i == item->ri_total, file: fs/xfs/xfs_log_recover.c, line: 2135 Yup, xlog_recover_do_reg_buffer() doesn't handle contigous dirty regions being broken up into multiple regions by the log formatting code. That's an easy fix, though - if the number of contiguous dirty bits exceeds the length of the region being copied out of the log, only account for the number of dirty bits that region covers, and then loop again and copy more from the next region. It's a 2 line fix. Now xfstests xfs/085 passes, we have one less piece of mystery code, and one more important piece of knowledge about how to structure new log format items.. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-05-01xfs: fix da node magic number mismatchesDave Chinner
Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-30xfs: Teach dquot recovery about CONFIG_XFS_QUOTADave Chinner
Fix a build error when CONFIG_XFS_QUOTA=n: fs/built-in.o: In function `xlog_recovery_validate_buf_type': /home/dave/src/build/x86-64/xfsdev/fs/xfs/xfs_log_recover.c:1948: undefined reference to `xfs_dquot_buf_ops' Reported-by: Michael L. Semon <mlsemon35@gmail.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27xfs: implement extended feature masksDave Chinner
The version 5 superblock has extended feature masks for compatible, incompatible and read-only compatible feature sets. Implement the masking and mount-time checking for these feature masks. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27xfs: add CRC checks to the superblockDave Chinner
With the addition of CRCs, there is such a wide and varied change to the on disk format that it makes sense to bump the superblock version number rather than try to use feature bits for all the new functionality. This commit introduces all the new superblock fields needed for all the new functionality: feature masks similar to ext4, separate project quota inodes, a LSN field for recovery and the CRC field. This commit does not bump the superblock version number, however. That will be done as a separate commit at the end of the series after all the new functionality is present so we switch it all on in one commit. This means that we can slowly introduce the changes without them being active and hence maintain bisectability of the tree. This patch is based on a patch originally written by myself back from SGI days, which was subsequently modified by Christoph Hellwig. There is relatively little of that patch remaining, but the history of the patch still should be acknowledged here. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27xfs: buffer type overruns blf_flags fieldDave Chinner
The buffer type passed to log recvoery in the buffer log item overruns the blf_flags field. I had assumed that flags field was a 32 bit value, and it turns out it is a unisgned short. Therefore having 19 flags doesn't really work. Convert the buffer type field to numeric value, and use the top 5 bits of the flags field for it. We currently have 17 types of buffers, so using 5 bits gives us plenty of room for expansion in future.... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27xfs: add buffer types to directory and attribute buffersDave Chinner
Add buffer types to the buffer log items so that log recovery can validate the buffers and calculate CRCs correctly after the buffers are recovered. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27xfs: add CRC checks to remote symlinksDave Chinner
Add a header to the remote symlink block, containing location and owner information, as well as CRCs and LSN fields. This requires verifiers to be added to the remote symlink buffers for CRC enabled filesystems. This also fixes a bug reading multiple block symlinks, where the second block overwrites the first block when copying out the link name. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add version 3 inode format with CRCsChristoph Hellwig
Add a new inode version with a larger core. The primary objective is to allow for a crc of the inode, and location information (uuid and ino) to verify it was written in the right place. We also extend it by: a creation time (for Samba); a changecount (for NFSv4); a flush sequence (in LSN format for recovery); an additional inode flags field; and some additional padding. These additional fields are not implemented yet, but already laid out in the structure. [dchinner@redhat.com] Added LSN and flags field, some factoring and rework to capture all the necessary information in the crc calculation. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add CRC checks for quota blocksChristoph Hellwig
Use the reserved space in struct xfs_dqblk to store a UUID and a crc for the quota blocks. [dchinner@redhat.com] Add a LSN field and update for current verifier infrastructure. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add CRC checks to the AGIDave Chinner
Same set of changes made to the AGF need to be made to the AGI. This patch has a similar history to the AGF, hence a similar sign-off chain. Signed-off-by: Dave Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dgc@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add CRC checks to the AGFLChristoph Hellwig
Add CRC checks, location information and a magic number to the AGFL. Previously the AGFL was just a block containing nothing but the free block pointers. The new AGFL has a real header with the usual boilerplate instead, so that we can verify it's not corrupted and written into the right place. [dchinner@redhat.com] Added LSN field, reworked significantly to fit into new verifier structure and growfs structure, enabled full verifier functionality now there is a header to verify and we can guarantee an initialised AGFL. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add CRC checks to the AGFDave Chinner
The AGF already has some self identifying fields (e.g. the sequence number) so we only need to add the uuid to it to identify the filesystem it belongs to. The location is fixed based on the sequence number, so there's no need to add a block number, either. Hence the only additional fields are the CRC and LSN fields. These are unlogged, so place some space between the end of the logged fields and them so that future expansion of the AGF for logged fields can be placed adjacent to the existing logged fields and hence not complicate the field-derived range based logging we currently have. Based originally on a patch from myself, modified further by Christoph Hellwig and then modified again to fit into the verifier structure with additional fields by myself. The multiple signed-off-by tags indicate the age and history of this patch. Signed-off-by: Dave Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-21xfs: add support for large btree blocksChristoph Hellwig
Add support for larger btree blocks that contains a CRC32C checksum, a filesystem uuid and block number for detecting filesystem consistency and out of place writes. [dchinner@redhat.com] Also include an owner field to allow reverse mappings to be implemented for improved repairability and a LSN field to so that log recovery can easily determine the last modification that made it to disk for each buffer. [dchinner@redhat.com] Add buffer log format flags to indicate the type of buffer to recovery so that we don't have to do blind magic number tests to determine what the buffer is. [dchinner@redhat.com] Modified to fit into the verifier structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-05xfs: don't free EFIs before the EFDs are committedDave Chinner
Filesystems are occasionally being shut down with this error: xfs_trans_ail_delete_bulk: attempting to delete a log item that is not in the AIL. It was diagnosed to be related to the EFI/EFD commit order when the EFI and EFD are in different checkpoints and the EFD is committed before the EFI here: http://oss.sgi.com/archives/xfs/2013-01/msg00082.html The real problem is that a single bit cannot fully describe the states that the EFI/EFD processing can be in. These completion states are: EFI EFI in AIL EFD Result committed/unpinned Yes committed OK committed/pinned No committed Shutdown uncommitted No committed Shutdown Note that the "result" field is what should happen, not what does happen. The current logic is broken and handles the first two cases correctly by luck. That is, the code will free the EFI if the XFS_EFI_COMMITTED bit is *not* set, rather than if it is set. The inverted logic "works" because if both EFI and EFD are committed, then the first __xfs_efi_release() call clears the XFS_EFI_COMMITTED bit, and the second frees the EFI item. Hence as long as xfs_efi_item_committed() has been called, everything appears to be fine. It is the third case where the logic fails - where xfs_efd_item_committed() is called before xfs_efi_item_committed(), and that results in the EFI being freed before it has been committed. That is the bug that triggered the shutdown, and hence keeping track of whether the EFI has been committed or not is insufficient to correctly order the EFI/EFD operations w.r.t. the AIL. What we really want is this: the EFI is always placed into the AIL before the last reference goes away. The only way to guarantee that is that the EFI is not freed until after it has been unpinned *and* the EFD has been committed. That is, restructure the logic so that the only case that can occur is the first case. This can be done easily by replacing the XFS_EFI_COMMITTED with an EFI reference count. The EFI is initialised with it's own count, and that is not released until it is unpinned. However, there is a complication to this method - the high level EFI/EFD code in xfs_bmap_finish() does not hold direct references to the EFI structure, and runs a transaction commit between the EFI and EFD processing. Hence the EFI can be freed even before the EFD is created using such a method. Further, log recovery uses the AIL for tracking EFI/EFDs that need to be recovered, but it uses the AIL *differently* to the EFI transaction commit. Hence log recovery never pins or unpins EFIs, so we can't drop the EFI reference count indirectly to free the EFI. However, this doesn't prevent us from using a reference count here. There is a 1:1 relationship between EFIs and EFDs, so when we initialise the EFI we can take a reference count for the EFD as well. This solves the xfs_bmap_finish() issue - the EFI will never be freed until the EFD is processed. In terms of log recovery, during the committing of the EFD we can look for the XFS_EFI_RECOVERED bit being set and drop the EFI reference as well, thereby ensuring everything works correctly there as well. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2013-02-28hlist: drop the node parameter from iteratorsSasha Levin
I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-03xfs: fix sparse reported log CRC endian issueDave Chinner
Not a bug as such, just warning noise from the xlog_cksum() returning a __be32 type when it should be returning a __le32 type. On Wed, Nov 28, 2012 at 08:30:59AM -0500, Christoph Hellwig wrote: > But why are we storing the crc field little endian while all other on > disk formats are big endian? (And yes I realize it might as well have > been me who did that back in the idea, but I still have no idea why) Because the CRC always returns the calcuation LE format, even on BE systems. So rather than always having to byte swap it everywhere and have all the force casts and anootations for sparse, it seems simpler to just make it a __le32 everywhere.... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Ben Myers <bpm@sgi.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-20xfs: add CRC checks to the logChristoph Hellwig
Implement CRCs for the log buffers. We re-use a field in struct xlog_rec_header that was used for a weak checksum of the log buffer payload in debug builds before. The new checksumming uses the crc32c checksum we will use elsewhere in XFS, and also protects the record header and addition cycle data. Due to this there are some interesting changes in xlog_sync, as we need to do the cycle wrapping for the split buffer case much earlier, as we would touch the buffer after generating the checksum otherwise. The CRC calculation is always enabled, even for non-CRC filesystems, as adding this CRC does not change the log format. On non-CRC filesystems, only issue an alert if a CRC mismatch is found and allow recovery to continue - this will act as an indicator that log recovery problems are a result of log corruption. On CRC enabled filesystems, however, log recovery will fail. Note that existing debug kernels will write a simple checksum value to the log, so the first time this is run on a filesystem taht was last used on a debug kernel it will through CRC mismatch warning errors. These can be ignored. Initially based on a patch from Dave Chinner, then modified significantly by Christoph Hellwig. Modified again by Dave Chinner to get to this version. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: convert buffer verifiers to an ops structure.Dave Chinner
To separate the verifiers from iodone functions and associate read and write verifiers at the same time, introduce a buffer verifier operations structure to the xfs_buf. This avoids the need for assigning the write verifier, clearing the iodone function and re-running ioend processing in the read verifier, and gets rid of the nasty "b_pre_io" name for the write verifier function pointer. If we ever need to, it will also be easier to add further content specific callbacks to a buffer with an ops structure in place. We also avoid needing to export verifier functions, instead we can simply export the ops structures for those that are needed outside the function they are defined in. This patch also fixes a directory block readahead verifier issue it exposed. This patch also adds ops callbacks to the inode/alloc btree blocks initialised by growfs. These will need more work before they will work with CRCs. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: verify superblocks as they are read from diskDave Chinner
Add a superblock verify callback function and pass it into the buffer read functions. Remove the now redundant verification code that is currently in use. Adding verification shows that secondary superblocks never have their "sb_inprogress" flag cleared by mkfs.xfs, so when validating the secondary superblocks during a grow operation we have to avoid checking this field. Even if we fix mkfs, we will still have to ignore this field for verification purposes unless a version of mkfs that does not have this bug was used. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-16xfs: make buffer read verication an IO completion functionDave Chinner
Add a verifier function callback capability to the buffer read interfaces. This will be used by the callers to supply a function that verifies the contents of the buffer when it is read from disk. This patch does not provide callback functions, but simply modifies the interfaces to allow them to be called. The reason for adding this to the read interfaces is that it is very difficult to tell fom the outside is a buffer was just read from disk or whether we just pulled it out of cache. Supplying a callbck allows the buffer cache to use it's internal knowledge of the buffer to execute it only when the buffer is read from disk. It is intended that the verifier functions will mark the buffer with an EFSCORRUPTED error when verification fails. This allows the reading context to distinguish a verification error from an IO error, and potentially take further actions on the buffer (e.g. attempt repair) based on the error reported. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Phil White <pwhite@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>
2012-11-07xfs: fix reading of wrapped log dataDave Chinner
Commit 4439647 ("xfs: reset buffer pointers before freeing them") in 3.0-rc1 introduced a regression when recovering log buffers that wrapped around the end of log. The second part of the log buffer at the start of the physical log was being read into the header buffer rather than the data buffer, and hence recovery was seeing garbage in the data buffer when it got to the region of the log buffer that was incorrectly read. Cc: <stable@vger.kernel.org> # 3.0.x, 3.2.x, 3.4.x 3.6.x Reported-by: Torsten Kaiser <just.for.lkml@googlemail.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mark Tinguely <tinguely@sgi.com> Signed-off-by: Ben Myers <bpm@sgi.com>