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authorLong Li <leo.lilong@huawei.com>2022-11-17 06:20:20 +0300
committerDarrick J. Wong <djwong@kernel.org>2022-11-17 06:20:20 +0300
commit59f6ab40fd8735c9a1a15401610a31cc06a0bbd6 (patch)
treea92755245dfe554ce24e8454df4bf93c686ce032 /fs/xfs/xfs_mount.c
parent2653d53345bda90604f673bb211dd060a5a5c232 (diff)
downloadlinux-59f6ab40fd8735c9a1a15401610a31cc06a0bbd6.tar.xz
xfs: fix sb write verify for lazysbcount
When lazysbcount is enabled, fsstress and loop mount/unmount test report the following problems: XFS (loop0): SB summary counter sanity check failed XFS (loop0): Metadata corruption detected at xfs_sb_write_verify+0x13b/0x460, xfs_sb block 0x0 XFS (loop0): Unmount and run xfs_repair XFS (loop0): First 128 bytes of corrupted metadata buffer: 00000000: 58 46 53 42 00 00 10 00 00 00 00 00 00 28 00 00 XFSB.........(.. 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000020: 69 fb 7c cd 5f dc 44 af 85 74 e0 cc d4 e3 34 5a i.|._.D..t....4Z 00000030: 00 00 00 00 00 20 00 06 00 00 00 00 00 00 00 80 ..... .......... 00000040: 00 00 00 00 00 00 00 81 00 00 00 00 00 00 00 82 ................ 00000050: 00 00 00 01 00 0a 00 00 00 00 00 04 00 00 00 00 ................ 00000060: 00 00 0a 00 b4 b5 02 00 02 00 00 08 00 00 00 00 ................ 00000070: 00 00 00 00 00 00 00 00 0c 09 09 03 14 00 00 19 ................ XFS (loop0): Corruption of in-memory data (0x8) detected at _xfs_buf_ioapply +0xe1e/0x10e0 (fs/xfs/xfs_buf.c:1580). Shutting down filesystem. XFS (loop0): Please unmount the filesystem and rectify the problem(s) XFS (loop0): log mount/recovery failed: error -117 XFS (loop0): log mount failed This corruption will shutdown the file system and the file system will no longer be mountable. The following script can reproduce the problem, but it may take a long time. #!/bin/bash device=/dev/sda testdir=/mnt/test round=0 function fail() { echo "$*" exit 1 } mkdir -p $testdir while [ $round -lt 10000 ] do echo "******* round $round ********" mkfs.xfs -f $device mount $device $testdir || fail "mount failed!" fsstress -d $testdir -l 0 -n 10000 -p 4 >/dev/null & sleep 4 killall -w fsstress umount $testdir xfs_repair -e $device > /dev/null if [ $? -eq 2 ];then echo "ERR CODE 2: Dirty log exception during repair." exit 1 fi round=$(($round+1)) done With lazysbcount is enabled, There is no additional lock protection for reading m_ifree and m_icount in xfs_log_sb(), if other cpu modifies the m_ifree, this will make the m_ifree greater than m_icount. For example, consider the following sequence and ifreedelta is postive: CPU0 CPU1 xfs_log_sb xfs_trans_unreserve_and_mod_sb ---------- ------------------------------ percpu_counter_sum(&mp->m_icount) percpu_counter_add_batch(&mp->m_icount, idelta, XFS_ICOUNT_BATCH) percpu_counter_add(&mp->m_ifree, ifreedelta); percpu_counter_sum(&mp->m_ifree) After this, incorrect inode count (sb_ifree > sb_icount) will be writen to the log. In the subsequent writing of sb, incorrect inode count (sb_ifree > sb_icount) will fail to pass the boundary check in xfs_validate_sb_write() that cause the file system shutdown. When lazysbcount is enabled, we don't need to guarantee that Lazy sb counters are completely correct, but we do need to guarantee that sb_ifree <= sb_icount. On the other hand, the constraint that m_ifree <= m_icount must be satisfied any time that there /cannot/ be other threads allocating or freeing inode chunks. If the constraint is violated under these circumstances, sb_i{count,free} (the ondisk superblock inode counters) maybe incorrect and need to be marked sick at unmount, the count will be rebuilt on the next mount. Fixes: 8756a5af1819 ("libxfs: add more bounds checking to sb sanity checks") Signed-off-by: Long Li <leo.lilong@huawei.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Diffstat (limited to 'fs/xfs/xfs_mount.c')
-rw-r--r--fs/xfs/xfs_mount.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index e8bb3c2e847e..fb87ffb48f7f 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -538,6 +538,20 @@ xfs_check_summary_counts(
return 0;
}
+static void
+xfs_unmount_check(
+ struct xfs_mount *mp)
+{
+ if (xfs_is_shutdown(mp))
+ return;
+
+ if (percpu_counter_sum(&mp->m_ifree) >
+ percpu_counter_sum(&mp->m_icount)) {
+ xfs_alert(mp, "ifree/icount mismatch at unmount");
+ xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
+ }
+}
+
/*
* Flush and reclaim dirty inodes in preparation for unmount. Inodes and
* internal inode structures can be sitting in the CIL and AIL at this point,
@@ -1077,6 +1091,7 @@ xfs_unmountfs(
if (error)
xfs_warn(mp, "Unable to free reserved block pool. "
"Freespace may not be correct on next mount.");
+ xfs_unmount_check(mp);
xfs_log_unmount(mp);
xfs_da_unmount(mp);