Btrfs: avoid null dereference and leaks when bailing from open_ctree()
Fix bugs introduced by 6c41761f. Firstly, after failing to allocate any
of the tree roots (first 'goto fail' in open_ctree()) we would
dereference a NULL fs_info pointer in free_fs_info(). Secondly, after
failures from init_srcu_struct(), setup_bdi() and new_inode() we would
leak all earlier allocated roots: fs_info fields haven't been
initialized yet so free_fs_info() is rendered useless.
Fix this by initializing fs_info pointer and fs_info fields before any
allocations happen.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e53a5bb..91db90b 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1890,31 +1890,32 @@
u64 features;
struct btrfs_key location;
struct buffer_head *bh;
- struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
- GFP_NOFS);
- struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
- GFP_NOFS);
+ struct btrfs_super_block *disk_super;
struct btrfs_root *tree_root = btrfs_sb(sb);
- 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),
- GFP_NOFS);
+ struct btrfs_fs_info *fs_info = tree_root->fs_info;
+ struct btrfs_root *extent_root;
+ struct btrfs_root *csum_root;
+ struct btrfs_root *chunk_root;
+ struct btrfs_root *dev_root;
struct btrfs_root *log_tree_root;
-
int ret;
int err = -EINVAL;
int num_backups_tried = 0;
int backup_index = 0;
- struct btrfs_super_block *disk_super;
+ extent_root = fs_info->extent_root =
+ kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+ csum_root = fs_info->csum_root =
+ kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+ chunk_root = fs_info->chunk_root =
+ kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+ dev_root = fs_info->dev_root =
+ kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
- if (!extent_root || !tree_root || !tree_root->fs_info ||
- !chunk_root || !dev_root || !csum_root) {
+ if (!extent_root || !csum_root || !chunk_root || !dev_root) {
err = -ENOMEM;
goto fail;
}
- fs_info = tree_root->fs_info;
ret = init_srcu_struct(&fs_info->subvol_srcu);
if (ret) {
@@ -1954,12 +1955,6 @@
mutex_init(&fs_info->reloc_mutex);
init_completion(&fs_info->kobj_unregister);
- fs_info->tree_root = tree_root;
- fs_info->extent_root = extent_root;
- fs_info->csum_root = csum_root;
- fs_info->chunk_root = chunk_root;
- fs_info->dev_root = dev_root;
- fs_info->fs_devices = fs_devices;
INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
INIT_LIST_HEAD(&fs_info->space_info);
btrfs_mapping_init(&fs_info->mapping_tree);