xfs: when replaying bmap operations, don't let unlinked inodes get reaped

Log recovery will iget an inode to replay BUI items and iput the inode
when it's done.  Unfortunately, if the inode was unlinked, the iput
will see that i_nlink == 0 and decide to truncate & free the inode,
which prevents us from replaying subsequent BUIs.  We can't skip the
BUIs because we have to replay all the redo items to ensure that
atomic operations complete.

Since unlinked inode recovery will reap the inode anyway, we can
safely introduce a new inode flag to indicate that an inode is in this
'unlinked recovery' state and should not be auto-reaped in the
drop_inode path.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 204b794cebd5..35c04a790754 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1008,6 +1008,16 @@ xfs_fs_drop_inode(
 {
 	struct xfs_inode	*ip = XFS_I(inode);
 
+	/*
+	 * If this unlinked inode is in the middle of recovery, don't
+	 * drop the inode just yet; log recovery will take care of
+	 * that.  See the comment for this inode flag.
+	 */
+	if (ip->i_flags & XFS_IRECOVERY) {
+		ASSERT(ip->i_mount->m_log->l_flags & XLOG_RECOVERY_NEEDED);
+		return 0;
+	}
+
 	return generic_drop_inode(inode) || (ip->i_flags & XFS_IDONTCACHE);
 }