Commit fd7ba1c1 authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: add nesting tags to the locking helpers 



We will need these when we switch to an rwsem, so plumb in the
infrastructure here to use later on.  I violate the 80 character limit
some here because it'll be cleaned up later.

Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 51899412

fs/btrfs/ctree.c

+8 −3
Original line number Diff line number Diff line
@@ -2875,7 +2875,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
			} else {

				if (!btrfs_tree_read_lock_atomic(b)) {

					btrfs_set_path_blocking(p);

					__btrfs_tree_read_lock(b, p->recurse);

					__btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,

							       p->recurse);

				}

				p->locks[level] = BTRFS_READ_LOCK;

			}
@@ -5453,7 +5454,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, 
			}

			if (!ret) {

				btrfs_set_path_blocking(path);

				__btrfs_tree_read_lock(next, path->recurse);

				__btrfs_tree_read_lock(next,

						       BTRFS_NESTING_NORMAL,

						       path->recurse);

			}

			next_rw_lock = BTRFS_READ_LOCK;

		}
@@ -5488,7 +5491,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, 
			ret = btrfs_try_tree_read_lock(next);

			if (!ret) {

				btrfs_set_path_blocking(path);

				__btrfs_tree_read_lock(next, path->recurse);

				__btrfs_tree_read_lock(next,

						       BTRFS_NESTING_NORMAL,

						       path->recurse);

			}

			next_rw_lock = BTRFS_READ_LOCK;

		}

fs/btrfs/locking.c

+10 −4
Original line number Diff line number Diff line
@@ -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, bool recurse)

void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,

			    bool recurse)

{

	u64 start_ns = 0;
@@ -282,7 +283,7 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse) 


void btrfs_tree_read_lock(struct extent_buffer *eb)

{

	__btrfs_tree_read_lock(eb, false);

	__btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, false);

}



/*
@@ -415,7 +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;
@@ -440,6 +441,11 @@ void btrfs_tree_lock(struct extent_buffer *eb) 
	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).
@@ -565,7 +571,7 @@ struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root, 


	while (1) {

		eb = btrfs_root_node(root);

		__btrfs_tree_read_lock(eb, recurse);

		__btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, recurse);

		if (eb == root->node)

			break;

		btrfs_tree_read_unlock(eb);

fs/btrfs/locking.h

+24 −1
Original line number Diff line number Diff line
@@ -16,12 +16,35 @@ 
#define BTRFS_WRITE_LOCK_BLOCKING 3

#define BTRFS_READ_LOCK_BLOCKING 4



/*

 * We are limited in number of subclasses by MAX_LOCKDEP_SUBCLASSES, which at

 * the time of this patch is 8, which is how many we use.  Keep this in mind if

 * you decide you want to add another subclass.

 */

enum btrfs_lock_nesting {

	BTRFS_NESTING_NORMAL,



	/*

	 * We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so

	 * add this in here and add a static_assert to keep us from going over

	 * the limit.  As of this writing we're limited to 8, and we're

	 * definitely using 8, hence this check to keep us from messing up in

	 * the future.

	 */

	BTRFS_NESTING_MAX,

};



static_assert(BTRFS_NESTING_MAX <= MAX_LOCKDEP_SUBCLASSES,

	      "too many lock subclasses defined");



struct btrfs_path;



void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest);

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, enum btrfs_lock_nesting nest,

			    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);