diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2020-08-20 11:46:01 -0400 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-10-07 12:12:16 +0200 |
| commit | 51899412dd95b2d9f50297c527b22ada3da0000c (patch) | |
| tree | 8f5b2c4d45f492cb6b7c917e4af30043314c9690 /fs/btrfs/locking.h | |
| parent | 329ced799be881feab445b68163cd3869340cc08 (diff) | |
btrfs: introduce btrfs_path::recurse
Our current tree locking stuff allows us to recurse with read locks if
we're already holding the write lock. This is necessary for the space
cache inode, as we could be holding a lock on the root_tree root when we
need to cache a block group, and thus need to be able to read down the
root_tree to read in the inode cache.
We can get away with this in our current locking, but we won't be able
to with a rwsem. Handle this by purposefully annotating the places
where we require recursion, so that in the future we can maybe come up
with a way to avoid the recursion. In the case of the free space inode,
this will be superseded by the free space tree.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/locking.h')
| -rw-r--r-- | fs/btrfs/locking.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index d715846c10b8..31f6d6405c1d 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -21,6 +21,7 @@ struct btrfs_path; void btrfs_tree_lock(struct extent_buffer *eb); void btrfs_tree_unlock(struct extent_buffer *eb); +void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse); void btrfs_tree_read_lock(struct extent_buffer *eb); void btrfs_tree_read_unlock(struct extent_buffer *eb); void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb); @@ -29,6 +30,14 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb); int btrfs_try_tree_read_lock(struct extent_buffer *eb); int btrfs_try_tree_write_lock(struct extent_buffer *eb); int btrfs_tree_read_lock_atomic(struct extent_buffer *eb); +struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root); +struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root, + bool recurse); + +static inline struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root) +{ + return __btrfs_read_lock_root_node(root, false); +} #ifdef CONFIG_BTRFS_DEBUG static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) { |