[Ocfs2-devel] [PATCH 2/2] Ocfs2: Handle deletion of refcounted oprhan_inode correctly.

[Tristan Ye]

Current ocfs2 semantic for reflinking a file firstly create a
new orphan_inode in orphan_dir, then remove it to target dir
after refcounting operation done, these 2 steps makes logic
straightfoward, and guarantee a crash during reflinking can
be replayed(half-refcounted inode can be removed), while it
brings us another issue cause these 2 steps is acquiring the
orphan_dir lock respectively, the problem is, orphan_scan()
may detect the half-refcounted inode in orphan_dir as its
proper candidates to wipe off in a later time. actually it's
not of course, we'd handle this correctly.

Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
---
 fs/ocfs2/inode.c |   32 ++++++++++++++++++++++++--------
 1 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 88459bd..61fb546 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -892,14 +892,30 @@ static int ocfs2_query_inode_wipe(struct inode *inode,
 	di = (struct ocfs2_dinode *) di_bh->b_data;
 	if (!(di->i_flags & cpu_to_le32(OCFS2_ORPHANED_FL))) {
 		/* for lack of a better error? */
-		status = -EEXIST;
-		mlog(ML_ERROR,
-		     "Inode %llu (on-disk %llu) not orphaned! "
-		     "Disk flags  0x%x, inode flags 0x%x\n",
-		     (unsigned long long)oi->ip_blkno,
-		     (unsigned long long)le64_to_cpu(di->i_blkno),
-		     le32_to_cpu(di->i_flags), oi->ip_flags);
-		goto bail;
+		if (!(di->i_dyn_features &
+		      cpu_to_le16(OCFS2_HAS_REFCOUNT_FL))) {
+			status = -EEXIST;
+			mlog(ML_ERROR,
+			     "Inode %llu (on-disk %llu) not orphaned! "
+			     "Disk flags  0x%x, inode flags 0x%x\n",
+			     (unsigned long long)oi->ip_blkno,
+			     (unsigned long long)le64_to_cpu(di->i_blkno),
+			     le32_to_cpu(di->i_flags), oi->ip_flags);
+			goto bail;
+		} else {
+			/*
+			 * It did happen to us, though it's a rare case:
+			 * orphan_scan() detects the half-refcounted inode
+			 * in orphan_dir, and delete_inode() attempts to
+			 * wipe it after reflink operation done later. now
+			 * we're not allowed to delete such a valid inode,
+			 * instead, just bail out.
+			 */
+			mlog(0, "Skipping delete of %llu because it's a "
+			     "reflinked inode\n",
+			     (unsigned long long)oi->ip_blkno);
+			goto bail;
+		}
 	}
 
 	/* has someone already deleted us?! baaad... */
-- 
1.5.5