From f66bf042693b620133d39af8d2f13615f03eadfc Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 23 Jun 2015 08:47:20 +1000 Subject: xfs: don't truncate attribute extents if no extents exist The xfs_attr3_root_inactive() call from xfs_attr_inactive() assumes that attribute blocks exist to invalidate. It is possible to have an attribute fork without extents, however. Consider the case where the attribute fork is created towards the beginning of xfs_attr_set() but some part of the subsequent attribute set fails. If an inode in such a state hits xfs_attr_inactive(), it eventually calls xfs_dabuf_map() and possibly xfs_bmapi_read(). The former emits a filesystem corruption warning, returns an error that bubbles back up to xfs_attr_inactive(), and leads to destruction of the in-core attribute fork without an on-disk reset. If the inode happens to make it back through xfs_inactive() in this state (e.g., via a concurrent bulkstat that cycles the inode from the reclaim state and releases it), i_afp might not exist when xfs_bmapi_read() is called and causes a NULL dereference panic. A '-p 2' fsstress run to ENOSPC on a relatively small fs (1GB) reproduces these problems. The behavior is a regression caused by: 6dfe5a0 xfs: xfs_attr_inactive leaves inconsistent attr fork state behind ... which removed logic that avoided the attribute extent truncate when no extents exist. Restore this logic to ensure the attribute fork is destroyed and reset correctly if it exists without any allocated extents. cc: stable@vger.kernel.org # 3.12 to 4.0.x Signed-off-by: Brian Foster Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/xfs_attr_inactive.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c index 3fbf167cfb4c..73e75a87af50 100644 --- a/fs/xfs/xfs_attr_inactive.c +++ b/fs/xfs/xfs_attr_inactive.c @@ -435,8 +435,14 @@ xfs_attr_inactive( */ xfs_trans_ijoin(trans, dp, 0); - /* invalidate and truncate the attribute fork extents */ - if (dp->i_d.di_aformat != XFS_DINODE_FMT_LOCAL) { + /* + * Invalidate and truncate the attribute fork extents. Make sure the + * fork actually has attributes as otherwise the invalidation has no + * blocks to read and returns an error. In this case, just do the fork + * removal below. + */ + if (xfs_inode_hasattr(dp) && + dp->i_d.di_aformat != XFS_DINODE_FMT_LOCAL) { error = xfs_attr3_root_inactive(&trans, dp); if (error) goto out_cancel; -- cgit v1.2.3