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btrfs: remove bogus NULL checks in __btrfs_write_out_cache()

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Dan reported a new smatch warning in free-space-cache.c:

New smatch warnings:
fs/btrfs/free-space-cache.c:1207 write_pinned_extent_entries() warn: variable dereferenced before check 'block_group' (see line 1203)

But the check if the block_group pointer is NULL is bogus, because to
get to this point block_group::io_ctl has already been dereferenced
further up the call-chain when calling __btrfs_write_out_cache() from
btrfs_write_out_cache().

Remove the bogus checks for block_group == NULL in
__btrfs_write_out_cache() and it's siblings.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202601170636.WsePMV5H-lkp@intel.com/
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Johannes Thumshirn 2026-01-19 08:17:50 +01:00 • committed by David Sterba
parent 2aef934b56
commit 57a4a863cd
1 changed files with 4 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

11
fs/btrfs/free-space-cache.c
View file

@ -1080,7 +1080,7 @@ int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
struct btrfs_trim_range *trim_entry;
/* Get the cluster for this block_group if it exists */
if (block_group && !list_empty(&block_group->cluster_list)) {
if (!list_empty(&block_group->cluster_list)) {
cluster = list_first_entry(&block_group->cluster_list,
struct btrfs_free_cluster, block_group_list);
}
@ -1204,9 +1204,6 @@ static noinline_for_stack int write_pinned_extent_entries(
struct extent_io_tree *unpin = NULL;
int ret;
if (!block_group)
return 0;
/*
* We want to add any pinned extents to our free space cache
* so we don't leak the space
@ -1394,7 +1391,7 @@ static int __btrfs_write_out_cache(struct inode *inode,
if (ret)
return ret;
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
if (block_group->flags & BTRFS_BLOCK_GROUP_DATA) {
down_write(&block_group->data_rwsem);
spin_lock(&block_group->lock);
if (block_group->delalloc_bytes) {
@ -1466,7 +1463,7 @@ static int __btrfs_write_out_cache(struct inode *inode,
goto out_nospc;
}
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
if (block_group->flags & BTRFS_BLOCK_GROUP_DATA)
up_write(&block_group->data_rwsem);
/*
* Release the pages and unlock the extent, we will flush
@ -1501,7 +1498,7 @@ out_nospc:
cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
out_unlock:
if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
if (block_group->flags & BTRFS_BLOCK_GROUP_DATA)
up_write(&block_group->data_rwsem);
out: