diff options
Diffstat (limited to 'fs/btrfs/locking.c')
| -rw-r--r-- | fs/btrfs/locking.c | 45 |
1 files changed, 29 insertions, 16 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index f75612e18a82..66e02ebdd340 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -57,8 +57,8 @@ * performance reasons. * * - * Lock nesting - * ------------ + * Lock recursion + * -------------- * * A write operation on a tree might indirectly start a look up on the same * tree. This can happen when btrfs_cow_block locks the tree and needs to @@ -201,7 +201,7 @@ void btrfs_set_lock_blocking_read(struct extent_buffer *eb) * lock, but it won't change to or away from us. If we have the write * lock, we are the owner and it'll never change. */ - if (eb->lock_nested && current->pid == eb->lock_owner) + if (eb->lock_recursed && current->pid == eb->lock_owner) return; btrfs_assert_tree_read_locked(eb); atomic_inc(&eb->blocking_readers); @@ -225,7 +225,7 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb) * lock, but it won't change to or away from us. If we have the write * lock, we are the owner and it'll never change. */ - if (eb->lock_nested && current->pid == eb->lock_owner) + if (eb->lock_recursed && current->pid == eb->lock_owner) return; if (eb->blocking_writers == 0) { btrfs_assert_spinning_writers_put(eb); @@ -244,7 +244,8 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb) * * The rwlock is held upon exit. */ -void btrfs_tree_read_lock(struct extent_buffer *eb) +void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest, + bool recurse) { u64 start_ns = 0; @@ -263,8 +264,9 @@ again: * depends on this as it may be called on a partly * (write-)locked tree. */ - BUG_ON(eb->lock_nested); - eb->lock_nested = true; + WARN_ON(!recurse); + BUG_ON(eb->lock_recursed); + eb->lock_recursed = true; read_unlock(&eb->lock); trace_btrfs_tree_read_lock(eb, start_ns); return; @@ -279,6 +281,11 @@ again: trace_btrfs_tree_read_lock(eb, start_ns); } +void btrfs_tree_read_lock(struct extent_buffer *eb) +{ + __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, false); +} + /* * Lock extent buffer for read, optimistically expecting that there are no * contending blocking writers. If there are, don't wait. @@ -362,11 +369,11 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb) /* * if we're nested, we have the write lock. No new locking * is needed as long as we are the lock owner. - * The write unlock will do a barrier for us, and the lock_nested + * The write unlock will do a barrier for us, and the lock_recursed * field only matters to the lock owner. */ - if (eb->lock_nested && current->pid == eb->lock_owner) { - eb->lock_nested = false; + if (eb->lock_recursed && current->pid == eb->lock_owner) { + eb->lock_recursed = false; return; } btrfs_assert_tree_read_locked(eb); @@ -388,11 +395,11 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) /* * if we're nested, we have the write lock. No new locking * is needed as long as we are the lock owner. - * The write unlock will do a barrier for us, and the lock_nested + * The write unlock will do a barrier for us, and the lock_recursed * field only matters to the lock owner. */ - if (eb->lock_nested && current->pid == eb->lock_owner) { - eb->lock_nested = false; + if (eb->lock_recursed && current->pid == eb->lock_owner) { + eb->lock_recursed = false; return; } btrfs_assert_tree_read_locked(eb); @@ -409,7 +416,7 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) * * The rwlock is held for write upon exit. */ -void btrfs_tree_lock(struct extent_buffer *eb) +void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest) __acquires(&eb->lock) { u64 start_ns = 0; @@ -434,6 +441,11 @@ again: trace_btrfs_tree_lock(eb, start_ns); } +void btrfs_tree_lock(struct extent_buffer *eb) +{ + __btrfs_tree_lock(eb, BTRFS_NESTING_NORMAL); +} + /* * Release the write lock, either blocking or spinning (ie. there's no need * for an explicit blocking unlock, like btrfs_tree_read_unlock_blocking). @@ -552,13 +564,14 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root) * * Return: root extent buffer with read lock held */ -struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root) +struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root, + bool recurse) { struct extent_buffer *eb; while (1) { eb = btrfs_root_node(root); - btrfs_tree_read_lock(eb); + __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, recurse); if (eb == root->node) break; btrfs_tree_read_unlock(eb); |