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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>
This commit is contained in:
Ilya Dryomov 2011-11-09 00:08:15 +02:00
parent f23c8af8ca
commit 4d34b27895
1 changed files with 15 additions and 20 deletions
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35
fs/btrfs/disk-io.c
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@ -1890,31 +1890,32 @@ struct btrfs_root *open_ctree(struct super_block *sb,
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 @@ struct btrfs_root *open_ctree(struct super_block *sb,
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);