[PATCH v3 2/3] ocfs2: detect released suballocator bg for fh_to_[dentry|parent]

[Heming Zhao]

After ocfs2 has the ability to reclaim suballoc free bg, the
suballocator block group may be released. This change makes xfstest
case 426 failed.

The existed code call stack:

ocfs2_fh_to_dentry //or ocfs2_fh_to_parent
 ocfs2_get_dentry
  ocfs2_test_inode_bit
   ocfs2_test_suballoc_bit
    ocfs2_read_group_descriptor
     + read released bg, triggers validate fails, then cause -EROFS

how to fix:
The read bg failure is expectation, we should ignore this error.

Signed-off-by: Heming Zhao <heming.zhao@xxxxxxxx>
Reviewed-by: Su Yue <glass.su@xxxxxxxx>
---
 fs/ocfs2/suballoc.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index d62010166c34..9e847f59c9ef 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -3118,7 +3118,7 @@ static int ocfs2_test_suballoc_bit(struct ocfs2_super *osb,
 	struct ocfs2_group_desc *group;
 	struct buffer_head *group_bh = NULL;
 	u64 bg_blkno;
-	int status;
+	int status, quiet = 0, released;
 
 	trace_ocfs2_test_suballoc_bit((unsigned long long)blkno,
 				      (unsigned int)bit);
@@ -3134,11 +3134,15 @@ static int ocfs2_test_suballoc_bit(struct ocfs2_super *osb,
 
 	bg_blkno = group_blkno ? group_blkno :
 		   ocfs2_which_suballoc_group(blkno, bit);
-	status = ocfs2_read_group_descriptor(suballoc, alloc_di, bg_blkno,
-					     &group_bh);
-	if (status < 0) {
+	status = ocfs2_read_hint_group_descriptor(suballoc, alloc_di, bg_blkno,
+					     &group_bh, &released);
+	if (released) {
+		quiet = 1;
+		status = -EINVAL;
+		goto bail;
+	} else if (status < 0) {
 		mlog(ML_ERROR, "read group %llu failed %d\n",
-		     (unsigned long long)bg_blkno, status);
+				(unsigned long long)bg_blkno, status);
 		goto bail;
 	}
 
@@ -3148,7 +3152,7 @@ static int ocfs2_test_suballoc_bit(struct ocfs2_super *osb,
 bail:
 	brelse(group_bh);
 
-	if (status)
+	if (status && (!quiet))
 		mlog_errno(status);
 	return status;
 }
@@ -3168,7 +3172,7 @@ static int ocfs2_test_suballoc_bit(struct ocfs2_super *osb,
  */
 int ocfs2_test_inode_bit(struct ocfs2_super *osb, u64 blkno, int *res)
 {
-	int status;
+	int status, quiet = 0;
 	u64 group_blkno = 0;
 	u16 suballoc_bit = 0, suballoc_slot = 0;
 	struct inode *inode_alloc_inode;
@@ -3210,8 +3214,12 @@ int ocfs2_test_inode_bit(struct ocfs2_super *osb, u64 blkno, int *res)
 
 	status = ocfs2_test_suballoc_bit(osb, inode_alloc_inode, alloc_bh,
 					 group_blkno, blkno, suballoc_bit, res);
-	if (status < 0)
-		mlog(ML_ERROR, "test suballoc bit failed %d\n", status);
+	if (status < 0) {
+		if (status == -EINVAL)
+			quiet = 1;
+		else
+			mlog(ML_ERROR, "test suballoc bit failed %d\n", status);
+	}
 
 	ocfs2_inode_unlock(inode_alloc_inode, 0);
 	inode_unlock(inode_alloc_inode);
@@ -3219,7 +3227,7 @@ int ocfs2_test_inode_bit(struct ocfs2_super *osb, u64 blkno, int *res)
 	iput(inode_alloc_inode);
 	brelse(alloc_bh);
 bail:
-	if (status)
+	if (status && !quiet)
 		mlog_errno(status);
 	return status;
 }
-- 
2.35.3