diff options
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/ctree.h | 1 | ||||
-rw-r--r-- | fs/btrfs/disk-io.c | 5 | ||||
-rw-r--r-- | fs/btrfs/disk-io.h | 21 | ||||
-rw-r--r-- | fs/btrfs/extent-tree.c | 2 |
4 files changed, 26 insertions, 3 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index a84e59b..91a8ca7 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1746,6 +1746,7 @@ struct btrfs_root { int force_cow; spinlock_t root_item_lock; + atomic_t refs; }; struct btrfs_ioctl_defrag_range_args { diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index c65a5aa..90b643e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1216,6 +1216,7 @@ static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize, atomic_set(&root->log_writers, 0); atomic_set(&root->log_batch, 0); atomic_set(&root->orphan_inodes, 0); + atomic_set(&root->refs, 1); root->log_transid = 0; root->last_log_commit = 0; extent_io_tree_init(&root->dirty_log_pages, @@ -2052,7 +2053,7 @@ static void del_fs_roots(struct btrfs_fs_info *fs_info) } else { free_extent_buffer(gang[0]->node); free_extent_buffer(gang[0]->commit_root); - kfree(gang[0]); + btrfs_put_fs_root(gang[0]); } } @@ -3417,7 +3418,7 @@ static void free_fs_root(struct btrfs_root *root) kfree(root->free_ino_ctl); kfree(root->free_ino_pinned); kfree(root->name); - kfree(root); + btrfs_put_fs_root(root); } void btrfs_free_fs_root(struct btrfs_root *root) diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 534d583..b71acd6e 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); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index c989fe6..04066c2 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7469,7 +7469,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, } else { free_extent_buffer(root->node); free_extent_buffer(root->commit_root); - kfree(root); + btrfs_put_fs_root(root); } out_end_trans: btrfs_end_transaction_throttle(trans, tree_root); |