When compiling the bcachefs-tools, the following compilation warning
is reported:
libbcachefs/snapshot.c: In function ‘bch2_reconstruct_snapshots’:
libbcachefs/snapshot.c:915:19: warning: ‘tree_id’ may be used uninitialized
in this function [-Wmaybe-uninitialized]
915 | snapshot->v.tree = cpu_to_le32(tree_id);
libbcachefs/snapshot.c:903:6: note: ‘tree_id’ was declared here
903 | u32 tree_id;
| ^~~~~~~
This is a false alert, because @tree_id is changed in
bch2_snapshot_tree_create after it returns 0. And if this function
returns other value, @tree_id wouldn't be used. Thus there should
be nothing wrong in logical.
Although the report itself is a false alert, we can still make it more
explicit by setting the initial value of @tree_id to 0 (an invalid
tree ID).
Fixes: a292be3b68f3 ("bcachefs: Reconstruct missing snapshot nodes")
Signed-off-by: Hongbo Li <[email protected]>
---
v2:
- Revise the code based on Kent's reviews.
v1:
https://lore.kernel.org/all/[email protected]/T/#u
---
---
fs/bcachefs/snapshot.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c
index 2368218070d4..3aa4686cc71f 100644
--- a/fs/bcachefs/snapshot.c
+++ b/fs/bcachefs/snapshot.c
@@ -900,7 +900,8 @@ static int check_snapshot_exists(struct btree_trans *trans,
u32 id)
if (bch2_snapshot_equiv(c, id))
return 0;
- u32 tree_id;
+ /* 0 is an invalid tree ID */
+ u32 tree_id = 0;
int ret = bch2_snapshot_tree_create(trans, id, 0, &tree_id);
if (ret)
return ret;
--
2.34.1
