[PATCH 5.4 46/58] btrfs: deal with errors when checking if a dir entry exists during log replay

Greg Kroah-Hartman
2021-10-25T19:42:03Z

From: Filipe Manana <fdmanana@suse.com>

[ Upstream commit 77a5b9e3d14cbce49ceed2766b2003c034c066dc ]

Currently inode_in_dir() ignores errors returned from
btrfs_lookup_dir_index_item() and from btrfs_lookup_dir_item(), treating
any errors as if the directory entry does not exists in the fs/subvolume
tree, which is obviously not correct, as we can get errors such as -EIO
when reading extent buffers while searching the fs/subvolume's tree.

Fix that by making inode_in_dir() return the errors and making its only
caller, add_inode_ref(), deal with returned errors as well.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/tree-log.c | 47 ++++++++++++++++++++++++++++-----------------
1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 9d358dafef36..f34205569987 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -900,9 +900,11 @@ out:
}

/*
- * helper function to see if a given name and sequence number found
- * in an inode back reference are already in a directory and correctly
- * point to this inode
+ * See if a given name and sequence number found in an inode back reference are
+ * already in a directory and correctly point to this inode.
+ *
+ * Returns: < 0 on error, 0 if the directory entry does not exists and 1 if it
+ * exists.
*/
static noinline int inode_in_dir(struct btrfs_root *root,
struct btrfs_path *path,
@@ -911,29 +913,35 @@ static noinline int inode_in_dir(struct btrfs_root *root,
{
struct btrfs_dir_item *di;
struct btrfs_key location;
- int match = 0;
+ int ret = 0;

di = btrfs_lookup_dir_index_item(NULL, root, path, dirid,
index, name, name_len, 0);
- if (di && !IS_ERR(di)) {
+ if (IS_ERR(di)) {
+ if (PTR_ERR(di) != -ENOENT)
+ ret = PTR_ERR(di);
+ goto out;
+ } else if (di) {
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
if (location.objectid != objectid)
goto out;
- } else
+ } else {
goto out;
- btrfs_release_path(path);
+ }

+ btrfs_release_path(path);
di = btrfs_lookup_dir_item(NULL, root, path, dirid, name, name_len, 0);
- if (di && !IS_ERR(di)) {
- btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
- if (location.objectid != objectid)
- goto out;
- } else
+ if (IS_ERR(di)) {
+ ret = PTR_ERR(di);
goto out;
- match = 1;
+ } else if (di) {
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
+ if (location.objectid == objectid)
+ ret = 1;
+ }
out:
btrfs_release_path(path);
- return match;
+ return ret;
}

/*
@@ -1500,10 +1508,12 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
if (ret)
goto out;

- /* if we already have a perfect match, we're done */
- if (!inode_in_dir(root, path, btrfs_ino(BTRFS_I(dir)),
- btrfs_ino(BTRFS_I(inode)), ref_index,
- name, namelen)) {
+ ret = inode_in_dir(root, path, btrfs_ino(BTRFS_I(dir)),
+ btrfs_ino(BTRFS_I(inode)), ref_index,
+ name, namelen);
+ if (ret < 0) {
+ goto out;
+ } else if (ret == 0) {
/*
* look for a conflicting back reference in the
* metadata. if we find one we have to unlink that name
@@ -1561,6 +1571,7 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,

btrfs_update_inode(trans, root, inode);
}
+ /* Else, ret == 1, we already have a perfect match, we're done. */

ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + namelen;
kfree(name);
--
2.33.0