diff options
Diffstat (limited to 'fs/btrfs/disk-io.h')
| -rw-r--r-- | fs/btrfs/disk-io.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 534d583e609..b71acd6e1e5 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -76,6 +76,27 @@ void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root); void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root); void btrfs_free_fs_root(struct btrfs_root *root); + +/* + * This function is used to grab the root, and avoid it is freed when we + * access it. But it doesn't ensure that the tree is not dropped. + * + * If you want to ensure the whole tree is safe, you should use + * fs_info->subvol_srcu + */ +static inline struct btrfs_root *btrfs_grab_fs_root(struct btrfs_root *root) +{ + if (atomic_inc_not_zero(&root->refs)) + return root; + return NULL; +} + +static inline void btrfs_put_fs_root(struct btrfs_root *root) +{ + if (atomic_dec_and_test(&root->refs)) + kfree(root); +} + void btrfs_mark_buffer_dirty(struct extent_buffer *buf); int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid, int atomic); |