[PATCH] xfs: log the inode on directory sf to block format change

[Brian Foster <bfoster@redhat.com>]

When a directory changes from shortform (sf) to block format, the sf
format is copied to a temporary buffer, the inode format is modified
and the updated format filled with the dentries from the temporary
buffer. If the inode format is modified and attempt to grow the
inode fails (due to I/O error, for example), it is possible to
return an error while leaving the directory in an inconsistent state
and with an otherwise clean transaction. This results in corruption
of the associated directory and leads to xfs_dabuf_map() errors as
subsequent lookups cannot accurately determine the format of the
directory. This problem is reproduced occasionally by generic/475.

The fundamental problem is that xfs_dir2_sf_to_block() changes the
on-disk inode format without logging the inode. The inode is
eventually logged by the bmapi layer in the common case, but error
checking introduces the possibility of failing the high level
request before this happens.

Update xfs_dir2_sf_to_block() to log the inode when the on-disk
format is changed. This ensures that any subsequent errors after the
format has changed cause the transaction to abort.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/libxfs/xfs_dir2_block.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/xfs/libxfs/xfs_dir2_block.c b/fs/xfs/libxfs/xfs_dir2_block.c
index 9595ced393dc..3d1e5f6d64fd 100644
--- a/fs/xfs/libxfs/xfs_dir2_block.c
+++ b/fs/xfs/libxfs/xfs_dir2_block.c
@@ -1098,6 +1098,7 @@ xfs_dir2_sf_to_block(
 	xfs_idata_realloc(dp, -ifp->if_bytes, XFS_DATA_FORK);
 	xfs_bmap_local_to_extents_empty(dp, XFS_DATA_FORK);
 	dp->i_d.di_size = 0;
+	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
 	/*
 	 * Add block 0 to the inode.
-- 
2.20.1