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| author | Long Li <leo.lilong@huawei.com> | 2022-11-17 13:02:56 -0800 |
|---|---|---|
| committer | Darrick J. Wong <djwong@kernel.org> | 2022-11-21 10:00:01 -0800 |
| commit | 28b4b0596343d19d140da059eee0e5c2b5328731 (patch) | |
| tree | c33a8c9c5251fede2e7cafd56205187f909083d3 /fs/xfs | |
| parent | 64c80dfd04d1dd2ecf550542c8f3f41b54b20207 (diff) | |
| download | linux-28b4b0596343d19d140da059eee0e5c2b5328731.tar.bz2 | |
xfs: fix incorrect i_nlink caused by inode racing
The following error occurred during the fsstress test:
XFS: Assertion failed: VFS_I(ip)->i_nlink >= 2, file: fs/xfs/xfs_inode.c, line: 2452
The problem was that inode race condition causes incorrect i_nlink to be
written to disk, and then it is read into memory. Consider the following
call graph, inodes that are marked as both XFS_IFLUSHING and
XFS_IRECLAIMABLE, i_nlink will be reset to 1 and then restored to original
value in xfs_reinit_inode(). Therefore, the i_nlink of directory on disk
may be set to 1.
xfsaild
xfs_inode_item_push
xfs_iflush_cluster
xfs_iflush
xfs_inode_to_disk
xfs_iget
xfs_iget_cache_hit
xfs_iget_recycle
xfs_reinit_inode
inode_init_always
xfs_reinit_inode() needs to hold the ILOCK_EXCL as it is changing internal
inode state and can race with other RCU protected inode lookups. On the
read side, xfs_iflush_cluster() grabs the ILOCK_SHARED while under rcu +
ip->i_flags_lock, and so xfs_iflush/xfs_inode_to_disk() are protected from
racing inode updates (during transactions) by that lock.
Fixes: ff7bebeb91f8 ("xfs: refactor the inode recycling code") # goes further back than this
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')
| -rw-r--r-- | fs/xfs/xfs_icache.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index eae7427062cf..f35e2cee5265 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -342,6 +342,9 @@ xfs_iget_recycle( trace_xfs_iget_recycle(ip); + if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) + return -EAGAIN; + /* * We need to make it look like the inode is being reclaimed to prevent * the actual reclaim workers from stomping over us while we recycle @@ -355,6 +358,7 @@ xfs_iget_recycle( ASSERT(!rwsem_is_locked(&inode->i_rwsem)); error = xfs_reinit_inode(mp, inode); + xfs_iunlock(ip, XFS_ILOCK_EXCL); if (error) { /* * Re-initializing the inode failed, and we are in deep @@ -518,6 +522,8 @@ xfs_iget_cache_hit( if (ip->i_flags & XFS_IRECLAIMABLE) { /* Drops i_flags_lock and RCU read lock. */ error = xfs_iget_recycle(pag, ip); + if (error == -EAGAIN) + goto out_skip; if (error) return error; } else { |