[3/4] btrfs: backref, only search backref entries from leaves of the same root
diff mbox series

Message ID 20200207093818.23710-4-ethanwu@synology.com
State New
Headers show
Series
  • btrfs: improve normal backref walking
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Commit Message

ethanwu Feb. 7, 2020, 9:38 a.m. UTC
We could have some nodes/leaves in subvolume whose owner are not the
that subvolume. In this way, when we resolve normal backrefs of that
subvolume, we should avoid collecting those references from these blocks.

Signed-off-by: ethanwu <ethanwu@synology.com>
---
 fs/btrfs/backref.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Josef Bacik Feb. 7, 2020, 4:37 p.m. UTC | #1
On 2/7/20 4:38 AM, ethanwu wrote:
> We could have some nodes/leaves in subvolume whose owner are not the
> that subvolume. In this way, when we resolve normal backrefs of that
> subvolume, we should avoid collecting those references from these blocks.
> 
> Signed-off-by: ethanwu <ethanwu@synology.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef
Johannes Thumshirn Feb. 10, 2020, 10:54 a.m. UTC | #2
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Patch
diff mbox series

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index b4b68af48726..7e2e647ec846 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -443,11 +443,13 @@  static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 	 *    slot==nritems.
 	 * 2. We are searching for normal backref but bytenr of this leaf
 	 *    matches shared data backref
+	 * 3. The leaf owner is not equal to the root we are searching
 	 * For these cases, go to the next leaf before we continue.
 	 */
 	eb = path->nodes[0];
 	if (path->slots[0] >= btrfs_header_nritems(eb) ||
-		is_shared_data_backref(preftrees, eb->start)) {
+		is_shared_data_backref(preftrees, eb->start) ||
+		ref->root_id != btrfs_header_owner(eb)) {
 		if (time_seq == SEQ_LAST)
 			ret = btrfs_next_leaf(root, path);
 		else
@@ -466,9 +468,12 @@  static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 
 		/*
 		 * We are searching for normal backref but bytenr of this
-		 * leaf matches shared data backref.
+		 * leaf matches shared data backref. OR
+		 * The leaf owner is not equal to the root we are searching
 		 */
-		if (slot == 0 && is_shared_data_backref(preftrees, eb->start)) {
+		if (slot == 0 &&
+		    (is_shared_data_backref(preftrees, eb->start) ||
+		     ref->root_id != btrfs_header_owner(eb))) {
 			if (time_seq == SEQ_LAST)
 				ret = btrfs_next_leaf(root, path);
 			else