@@ -276,17 +276,25 @@ static void print_data_reloc_error(const struct btrfs_inode *inode, u64 file_off
u64 ref_root;
u8 ref_level;
- do {
+ while (true) {
ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
item_size, &ref_root,
&ref_level);
+ if (ret < 0) {
+ btrfs_warn_rl(fs_info,
+ "failed to resolve tree backref for logical %llu: %d",
+ logical, ret);
+ break;
+ }
+ if (ret > 0)
+ break;
+
btrfs_warn_rl(fs_info,
"csum error at logical %llu mirror %u: metadata %s (level %d) in tree %llu",
logical, mirror_num,
(ref_level ? "node" : "leaf"),
- (ret < 0 ? -1 : ref_level),
- (ret < 0 ? -1 : ref_root));
- } while (ret != 1);
+ ref_level, ref_root);
+ }
btrfs_release_path(&path);
} else {
struct btrfs_backref_walk_ctx ctx = { 0 };
@@ -473,11 +473,8 @@ static void scrub_print_common_warning(const char *errstr, struct btrfs_device *
struct extent_buffer *eb;
struct btrfs_extent_item *ei;
struct scrub_warning swarn;
- unsigned long ptr = 0;
u64 flags = 0;
- u64 ref_root;
u32 item_size;
- u8 ref_level = 0;
int ret;
/* Super block error, no need to search extent tree. */
@@ -507,19 +504,28 @@ static void scrub_print_common_warning(const char *errstr, struct btrfs_device *
item_size = btrfs_item_size(eb, path->slots[0]);
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
- do {
+ unsigned long ptr = 0;
+ u8 ref_level;
+ u64 ref_root;
+
+ while (true) {
ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
item_size, &ref_root,
&ref_level);
+ if (ret < 0) {
+ btrfs_warn(fs_info,
+ "failed to resolve tree backref for logical %llu: %d",
+ swarn.logical, ret);
+ break;
+ }
+ if (ret > 0)
+ break;
btrfs_warn_in_rcu(fs_info,
"%s at logical %llu on dev %s, physical %llu: metadata %s (level %d) in tree %llu",
- errstr, swarn.logical,
- btrfs_dev_name(dev),
- swarn.physical,
- ref_level ? "node" : "leaf",
- ret < 0 ? -1 : ref_level,
- ret < 0 ? -1 : ref_root);
- } while (ret != 1);
+ errstr, swarn.logical, btrfs_dev_name(dev),
+ swarn.physical, ref_level ? "node" : "leaf",
+ ref_level, ref_root);
+ }
btrfs_release_path(path);
} else {
struct btrfs_backref_walk_ctx ctx = { 0 };
[BUG] Smatch reports the following errors related to commit 3093caaa4d16 ("btrfs: output affected files when relocation fails"): fs/btrfs/inode.c:283 print_data_reloc_error() error: uninitialized symbol 'ref_level'. [CAUSE] That part of code is mostly copied from scrub, but unfortunately scrub code from the beginning is not doing the error handling properly. The offending code looks like this: do { ret = tree_backref_for_extent(); btrfs_warn_rl(); } while (ret != 1); There are several problems involved: - No error handling If that tree_backref_for_extent() failed, we would output the same error again and again, never really exit as it requires ret == 1 to exit. - Always do one extra output As tree_backref_for_extent() only return > 0 if there is no more backref item. This means after the last item we hit, we would output an invalid error message for ret > 0 case. [FIX] Fix the old code by: - Move @ref_root and @ref_level into the if branch And do not initialize them, so we can catch such uninitialized values just like what we do in the inode.c - Explicitly check the return value of tree_backref_for_extent() And handle ret < 0 and ret > 0 cases properly. - No more do {} while () loop Instead go while (true) {} loop since we will handle @ret manually. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Qu Wenruo <wqu@suse.com> --- fs/btrfs/inode.c | 16 ++++++++++++---- fs/btrfs/scrub.c | 28 +++++++++++++++++----------- 2 files changed, 29 insertions(+), 15 deletions(-)