btrfs: fix dereference before check

The superblock's ->s_fs_info is properly set in btrfs_fill_super, after
a call to open_ctree, which derefereces it before check. Although
tree_root is set via btrfs_set_super, let's be defensive and leave the
check in place.

Signed-off-by: David Sterba <dsterba@suse.cz>
This commit is contained in:
David Sterba 2011-04-19 16:45:00 +02:00
parent edc95aec57
commit 4891aca2da

View File

@ -1611,7 +1611,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *tree_root = btrfs_sb(sb);
struct btrfs_fs_info *fs_info = tree_root->fs_info;
struct btrfs_fs_info *fs_info = NULL;
struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
@ -1623,11 +1623,12 @@ struct btrfs_root *open_ctree(struct super_block *sb,
struct btrfs_super_block *disk_super;
if (!extent_root || !tree_root || !fs_info ||
if (!extent_root || !tree_root || !tree_root->fs_info ||
!chunk_root || !dev_root || !csum_root) {
err = -ENOMEM;
goto fail;
}
fs_info = tree_root->fs_info;
ret = init_srcu_struct(&fs_info->subvol_srcu);
if (ret) {