[PATCH 6.6.y] btrfs: don't ignore inode missing when replaying log tree

[Sasha Levin <sashal@kernel.org>]

From: Filipe Manana <fdmanana@suse.com>

[ Upstream commit 7ebf381a69421a88265d3c49cd0f007ba7336c9d ]

During log replay, at add_inode_ref(), we return -ENOENT if our current
inode isn't found on the subvolume tree or if a parent directory isn't
found. The error comes from btrfs_iget_logging() <- btrfs_iget() <-
btrfs_read_locked_inode().

The single caller of add_inode_ref(), replay_one_buffer(), ignores an
-ENOENT error because it expects that error to mean only that a parent
directory wasn't found and that is ok.

Before commit 5f61b961599a ("btrfs: fix inode lookup error handling during
log replay") we were converting any error when getting a parent directory
to -ENOENT and any error when getting the current inode to -EIO, so our
caller would fail log replay in case we can't find the current inode.
After that commit however in case the current inode is not found we return
-ENOENT to the caller and therefore it ignores the critical fact that the
current inode was not found in the subvolume tree.

Fix this by converting -ENOENT to 0 when we don't find a parent directory,
returning -ENOENT when we don't find the current inode and making the
caller, replay_one_buffer(), not ignore -ENOENT anymore.

Fixes: 5f61b961599a ("btrfs: fix inode lookup error handling during log replay")
CC: stable@vger.kernel.org # 6.16
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[ adapted btrfs_inode pointer usage to older inode API ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/tree-log.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 16434106c465..a64c525f647f 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1423,6 +1423,8 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 		btrfs_dir = btrfs_iget_logging(parent_objectid, root);
 		if (IS_ERR(btrfs_dir)) {
 			ret = PTR_ERR(btrfs_dir);
+			if (ret == -ENOENT)
+				ret = 0;
 			dir = NULL;
 			goto out;
 		}
@@ -1456,6 +1458,15 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
 				if (IS_ERR(btrfs_dir)) {
 					ret = PTR_ERR(btrfs_dir);
 					dir = NULL;
+					/*
+					 * A new parent dir may have not been
+					 * logged and not exist in the subvolume
+					 * tree, see the comment above before
+					 * the loop when getting the first
+					 * parent dir.
+					 */
+					if (ret == -ENOENT)
+						ret = 0;
 					goto out;
 				}
 				dir = &btrfs_dir->vfs_inode;
@@ -2611,9 +2622,8 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
 			   key.type == BTRFS_INODE_EXTREF_KEY) {
 			ret = add_inode_ref(wc->trans, root, log, path,
 					    eb, i, &key);
-			if (ret && ret != -ENOENT)
+			if (ret)
 				break;
-			ret = 0;
 		} else if (key.type == BTRFS_EXTENT_DATA_KEY) {
 			ret = replay_one_extent(wc->trans, root, path,
 						eb, i, &key);
-- 
2.50.1