Commit 9631e4cc authored by Josef Bacik's avatar Josef Bacik Committed by David Sterba
Browse files

btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks 



When we COW a block we are holding a lock on the original block, and
then we lock the new COW block.  Because our lockdep maps are based on
root + level, this will make lockdep complain.  We need a way to
indicate a subclass for locking the COW'ed block, so plumb through our
btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer,
and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks.

The reason I've added all this extra infrastructure is because there
will be need of different nesting classes in follow up patches.

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 fd7ba1c1

fs/btrfs/ctree.c

+32 −20
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans, 
		btrfs_node_key(buf, &disk_key, 0);



	cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,

			&disk_key, level, buf->start, 0);

			&disk_key, level, buf->start, 0, BTRFS_NESTING_NORMAL);

	if (IS_ERR(cow))

		return PTR_ERR(cow);
@@ -957,7 +957,8 @@ static struct extent_buffer *alloc_tree_block_no_bg_flush( 
					  const struct btrfs_disk_key *disk_key,

					  int level,

					  u64 hint,

					  u64 empty_size)

					  u64 empty_size,

					  enum btrfs_lock_nesting nest)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct extent_buffer *ret;
@@ -986,7 +987,7 @@ static struct extent_buffer *alloc_tree_block_no_bg_flush( 


	ret = btrfs_alloc_tree_block(trans, root, parent_start,

				     root->root_key.objectid, disk_key, level,

				     hint, empty_size);

				     hint, empty_size, nest);

	trans->can_flush_pending_bgs = true;



	return ret;
@@ -1009,7 +1010,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, 
			     struct extent_buffer *buf,

			     struct extent_buffer *parent, int parent_slot,

			     struct extent_buffer **cow_ret,

			     u64 search_start, u64 empty_size)

			     u64 search_start, u64 empty_size,

			     enum btrfs_lock_nesting nest)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct btrfs_disk_key disk_key;
@@ -1040,7 +1042,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, 
		parent_start = parent->start;



	cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key,

					   level, search_start, empty_size);

					   level, search_start, empty_size, nest);

	if (IS_ERR(cow))

		return PTR_ERR(cow);
@@ -1446,7 +1448,8 @@ static inline int should_cow_block(struct btrfs_trans_handle *trans, 
noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,

		    struct btrfs_root *root, struct extent_buffer *buf,

		    struct extent_buffer *parent, int parent_slot,

		    struct extent_buffer **cow_ret)

		    struct extent_buffer **cow_ret,

		    enum btrfs_lock_nesting nest)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	u64 search_start;
@@ -1485,7 +1488,7 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, 
	 */

	btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);

	ret = __btrfs_cow_block(trans, root, buf, parent,

				 parent_slot, cow_ret, search_start, 0);

				 parent_slot, cow_ret, search_start, 0, nest);



	trace_btrfs_cow_block(root, buf, *cow_ret);
@@ -1657,7 +1660,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, 
		err = __btrfs_cow_block(trans, root, cur, parent, i,

					&cur, search_start,

					min(16 * blocksize,

					    (end_slot - i) * blocksize));

					    (end_slot - i) * blocksize),

					BTRFS_NESTING_COW);

		if (err) {

			btrfs_tree_unlock(cur);

			free_extent_buffer(cur);
@@ -1855,7 +1859,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 


		btrfs_tree_lock(child);

		btrfs_set_lock_blocking_write(child);

		ret = btrfs_cow_block(trans, root, child, mid, 0, &child);

		ret = btrfs_cow_block(trans, root, child, mid, 0, &child,

				      BTRFS_NESTING_COW);

		if (ret) {

			btrfs_tree_unlock(child);

			free_extent_buffer(child);
@@ -1894,7 +1899,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		btrfs_tree_lock(left);

		btrfs_set_lock_blocking_write(left);

		wret = btrfs_cow_block(trans, root, left,

				       parent, pslot - 1, &left);

				       parent, pslot - 1, &left,

				       BTRFS_NESTING_COW);

		if (wret) {

			ret = wret;

			goto enospc;
@@ -1909,7 +1915,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, 
		btrfs_tree_lock(right);

		btrfs_set_lock_blocking_write(right);

		wret = btrfs_cow_block(trans, root, right,

				       parent, pslot + 1, &right);

				       parent, pslot + 1, &right,

				       BTRFS_NESTING_COW);

		if (wret) {

			ret = wret;

			goto enospc;
@@ -2077,7 +2084,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
			wret = 1;

		} else {

			ret = btrfs_cow_block(trans, root, left, parent,

					      pslot - 1, &left);

					      pslot - 1, &left,

					      BTRFS_NESTING_COW);

			if (ret)

				wret = 1;

			else {
@@ -2132,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, 
		} else {

			ret = btrfs_cow_block(trans, root, right,

					      parent, pslot + 1,

					      &right);

					      &right, BTRFS_NESTING_COW);

			if (ret)

				wret = 1;

			else {
@@ -2740,11 +2748,13 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
			btrfs_set_path_blocking(p);

			if (last_level)

				err = btrfs_cow_block(trans, root, b, NULL, 0,

						      &b);

						      &b,

						      BTRFS_NESTING_COW);

			else

				err = btrfs_cow_block(trans, root, b,

						      p->nodes[level + 1],

						      p->slots[level + 1], &b);

						      p->slots[level + 1], &b,

						      BTRFS_NESTING_COW);

			if (err) {

				ret = err;

				goto done;
@@ -3396,7 +3406,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans, 
		btrfs_node_key(lower, &lower_key, 0);



	c = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level,

					 root->node->start, 0);

					 root->node->start, 0,

					 BTRFS_NESTING_NORMAL);

	if (IS_ERR(c))

		return PTR_ERR(c);
@@ -3526,7 +3537,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, 
	btrfs_node_key(c, &disk_key, mid);



	split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level,

					     c->start, 0);

					     c->start, 0, BTRFS_NESTING_NORMAL);

	if (IS_ERR(split))

		return PTR_ERR(split);
@@ -3804,7 +3815,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root 


	/* cow and double check */

	ret = btrfs_cow_block(trans, root, right, upper,

			      slot + 1, &right);

			      slot + 1, &right, BTRFS_NESTING_COW);

	if (ret)

		goto out_unlock;
@@ -4045,7 +4056,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root 


	/* cow and double check */

	ret = btrfs_cow_block(trans, root, left,

			      path->nodes[1], slot - 1, &left);

			      path->nodes[1], slot - 1, &left,

			      BTRFS_NESTING_COW);

	if (ret) {

		/* we hit -ENOSPC, but it isn't fatal here */

		if (ret == -ENOSPC)
@@ -4312,7 +4324,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans, 
		btrfs_item_key(l, &disk_key, mid);



	right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,

					     l->start, 0);

					     l->start, 0, BTRFS_NESTING_NORMAL);

	if (IS_ERR(right))

		return PTR_ERR(right);

fs/btrfs/ctree.h

+4 −2
Original line number Diff line number Diff line
@@ -2526,7 +2526,8 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
					     u64 parent, u64 root_objectid,

					     const struct btrfs_disk_key *key,

					     int level, u64 hint,

					     u64 empty_size);

					     u64 empty_size,

					     enum btrfs_lock_nesting nest);

void btrfs_free_tree_block(struct btrfs_trans_handle *trans,

			   struct btrfs_root *root,

			   struct extent_buffer *buf,
@@ -2667,7 +2668,8 @@ struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, 
int btrfs_cow_block(struct btrfs_trans_handle *trans,

		    struct btrfs_root *root, struct extent_buffer *buf,

		    struct extent_buffer *parent, int parent_slot,

		    struct extent_buffer **cow_ret);

		    struct extent_buffer **cow_ret,

		    enum btrfs_lock_nesting nest);

int btrfs_copy_root(struct btrfs_trans_handle *trans,

		      struct btrfs_root *root,

		      struct extent_buffer *buf,

fs/btrfs/disk-io.c

+3 −2
Original line number Diff line number Diff line
@@ -1205,7 +1205,8 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans, 
	root->root_key.type = BTRFS_ROOT_ITEM_KEY;

	root->root_key.offset = 0;



	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);

	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,

				      BTRFS_NESTING_NORMAL);

	if (IS_ERR(leaf)) {

		ret = PTR_ERR(leaf);

		leaf = NULL;
@@ -1277,7 +1278,7 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans, 
	 */



	leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,

			NULL, 0, 0, 0);

			NULL, 0, 0, 0, BTRFS_NESTING_NORMAL);

	if (IS_ERR(leaf)) {

		btrfs_put_root(root);

		return ERR_CAST(leaf);

fs/btrfs/extent-tree.c

+7 −5
Original line number Diff line number Diff line
@@ -4656,7 +4656,8 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, 


static struct extent_buffer *

btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,

		      u64 bytenr, int level, u64 owner)

		      u64 bytenr, int level, u64 owner,

		      enum btrfs_lock_nesting nest)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct extent_buffer *buf;
@@ -4679,7 +4680,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root, 
	}



	btrfs_set_buffer_lockdep_class(owner, buf, level);

	btrfs_tree_lock(buf);

	__btrfs_tree_lock(buf, nest);

	btrfs_clean_tree_block(buf);

	clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
@@ -4725,7 +4726,8 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
					     u64 parent, u64 root_objectid,

					     const struct btrfs_disk_key *key,

					     int level, u64 hint,

					     u64 empty_size)

					     u64 empty_size,

					     enum btrfs_lock_nesting nest)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct btrfs_key ins;
@@ -4741,7 +4743,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS

	if (btrfs_is_testing(fs_info)) {

		buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,

					    level, root_objectid);

					    level, root_objectid, nest);

		if (!IS_ERR(buf))

			root->alloc_bytenr += blocksize;

		return buf;
@@ -4758,7 +4760,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans, 
		goto out_unuse;



	buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,

				    root_objectid);

				    root_objectid, nest);

	if (IS_ERR(buf)) {

		ret = PTR_ERR(buf);

		goto out_free_reserved;

fs/btrfs/ioctl.c

+2 −1
Original line number Diff line number Diff line
@@ -628,7 +628,8 @@ static noinline int create_subvol(struct inode *dir, 
	if (ret)

		goto fail;



	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);

	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,

				      BTRFS_NESTING_NORMAL);

	if (IS_ERR(leaf)) {

		ret = PTR_ERR(leaf);

		goto fail;