Commit 57a4a863 authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by David Sterba
Browse files

btrfs: remove bogus NULL checks in __btrfs_write_out_cache() 



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: default avatarkernel test robot <lkp@intel.com>
Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202601170636.WsePMV5H-lkp@intel.com/


Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 2aef934b

fs/btrfs/free-space-cache.c

+4 −7
Original line number Diff line number Diff line
@@ -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 @@ static int __btrfs_write_out_cache(struct inode *inode, 
	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: