This is a note to let you know that I've just added the patch titled
btrfs: initialize start_slot in btrfs_log_prealloc_extents
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-initialize-start_slot-in-btrfs_log_prealloc_ex.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 36424ad6f74cc330ae8c12d1afded8b2f8186139
Author: Josef Bacik <josef@xxxxxxxxxxxxxx>
Date: Tue Sep 5 12:15:24 2023 -0400
btrfs: initialize start_slot in btrfs_log_prealloc_extents
[ 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@xxxxxxxxx>
Tested-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 926b1d34e55cc..f75333d7b78a5 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4283,7 +4283,7 @@ 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))
