From: Josef Bacik josef@toxicpanda.com
[ Upstream commit b4c639f699349880b7918b861e1bd360442ec450 ]
Jens reported a compiler warning when using CONFIG_CC_OPTIMIZE_FOR_SIZE=y that looks like this
fs/btrfs/tree-log.c: In function ‘btrfs_log_prealloc_extents’: fs/btrfs/tree-log.c:4828:23: warning: ‘start_slot’ may be used uninitialized [-Wmaybe-uninitialized] 4828 | ret = copy_items(trans, inode, dst_path, path, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4829 | start_slot, ins_nr, 1, 0); | ~~~~~~~~~~~~~~~~~~~~~~~~~ fs/btrfs/tree-log.c:4725:13: note: ‘start_slot’ was declared here 4725 | int start_slot; | ^~~~~~~~~~
The compiler is incorrect, as we only use this code when ins_len > 0, and when ins_len > 0 we have start_slot properly initialized. However we generally find the -Wmaybe-uninitialized warnings valuable, so initialize start_slot to get rid of the warning.
Reported-by: Jens Axboe axboe@kernel.dk Tested-by: Jens Axboe axboe@kernel.dk Signed-off-by: Josef Bacik josef@toxicpanda.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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 0fe32c567ed74..23ec766eeb0a3 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4236,7 +4236,7 @@ static int btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans, struct extent_buffer *leaf; int slot; int ins_nr = 0; - int start_slot; + int start_slot = 0; int ret;
if (!(inode->flags & BTRFS_INODE_PREALLOC))