btrfs: Properly handle backref_in_log retval

This function can return a negative error value if btrfs_search_slot
errors for whatever reason or if btrfs_alloc_path runs out of memory.
This is currently problemattic because backref_in_log is treated by its
callers as if it returns boolean.

Fix this by adding proper error handling in callers. That also enables
the function to return the direct error code from btrfs_search_slot.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 1d7f22951ef26ac7c7f9312d5a517dbd477cdeb5..24fa6560655ca9dd2a5230fbc9a610c4f128ad46 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -952,7 +952,9 @@ static noinline int backref_in_log(struct btrfs_root *log,
                return -ENOMEM;
 
        ret = btrfs_search_slot(NULL, log, key, path, 0, 0);
-       if (ret != 0) {
+       if (ret < 0) {
+               goto out;
+       } else if (ret == 1) {
                ret = 0;
                goto out;
        }
@@ -1026,10 +1028,13 @@ again:
                                           (unsigned long)(victim_ref + 1),
                                           victim_name_len);
 
-                       if (!backref_in_log(log_root, &search_key,
-                                           parent_objectid,
-                                           victim_name,
-                                           victim_name_len)) {
+                       ret = backref_in_log(log_root, &search_key,
+                                            parent_objectid, victim_name,
+                                            victim_name_len);
+                       if (ret < 0) {
+                               kfree(victim_name);
+                               return ret;
+                       } else if (!ret) {
                                inc_nlink(&inode->vfs_inode);
                                btrfs_release_path(path);
 
@@ -1091,10 +1096,12 @@ again:
                        search_key.offset = btrfs_extref_hash(parent_objectid,
                                                              victim_name,
                                                              victim_name_len);
-                       ret = 0;
-                       if (!backref_in_log(log_root, &search_key,
-                                           parent_objectid, victim_name,
-                                           victim_name_len)) {
+                       ret = backref_in_log(log_root, &search_key,
+                                            parent_objectid, victim_name,
+                                            victim_name_len);
+                       if (ret < 0) {
+                               return ret;
+                       } else if (!ret) {
                                ret = -ENOENT;
                                victim_parent = read_one_inode(root,
                                                parent_objectid);
@@ -1869,16 +1876,19 @@ static bool name_in_log_ref(struct btrfs_root *log_root,
                            const u64 dirid, const u64 ino)
 {
        struct btrfs_key search_key;
+       int ret;
 
        search_key.objectid = ino;
        search_key.type = BTRFS_INODE_REF_KEY;
        search_key.offset = dirid;
-       if (backref_in_log(log_root, &search_key, dirid, name, name_len))
+       ret = backref_in_log(log_root, &search_key, dirid, name, name_len);
+       if (ret == 1)
                return true;
 
        search_key.type = BTRFS_INODE_EXTREF_KEY;
        search_key.offset = btrfs_extref_hash(dirid, name, name_len);
-       if (backref_in_log(log_root, &search_key, dirid, name, name_len))
+       ret = backref_in_log(log_root, &search_key, dirid, name, name_len);
+       if (ret == 1)
                return true;
 
        return false;