[PATCH 2/2] Btrfs: kill leave_spinning

[Liu Bo <bo.liu@linux.alibaba.com>]

As btrfs_clear_path_blocking() turns out to be a major source of lock
contention, we've kill it and without it btrfs_search_slot() and
btrfs_search_old_slot() are not able to return a path in spinning
mode, lets kill leave_spinning, too.

Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com>
---
 fs/btrfs/backref.c            |  3 ---
 fs/btrfs/ctree.c              | 16 +++-------------
 fs/btrfs/ctree.h              |  1 -
 fs/btrfs/delayed-inode.c      |  4 ----
 fs/btrfs/dir-item.c           |  1 -
 fs/btrfs/export.c             |  1 -
 fs/btrfs/extent-tree.c        |  7 -------
 fs/btrfs/extent_io.c          |  1 -
 fs/btrfs/file-item.c          |  4 ----
 fs/btrfs/free-space-tree.c    |  2 --
 fs/btrfs/inode-item.c         |  6 ------
 fs/btrfs/inode.c              |  8 --------
 fs/btrfs/ioctl.c              |  3 ---
 fs/btrfs/qgroup.c             |  2 --
 fs/btrfs/super.c              |  2 --
 fs/btrfs/tests/qgroup-tests.c |  4 ----
 16 files changed, 3 insertions(+), 62 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index ae750b1574a2..70c629b90710 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1613,13 +1613,11 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
 	s64 bytes_left = ((s64)size) - 1;
 	struct extent_buffer *eb = eb_in;
 	struct btrfs_key found_key;
-	int leave_spinning = path->leave_spinning;
 	struct btrfs_inode_ref *iref;
 
 	if (bytes_left >= 0)
 		dest[bytes_left] = '\0';
 
-	path->leave_spinning = 1;
 	while (1) {
 		bytes_left -= name_len;
 		if (bytes_left >= 0)
@@ -1665,7 +1663,6 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
 	}
 
 	btrfs_release_path(path);
-	path->leave_spinning = leave_spinning;
 
 	if (ret)
 		return ERR_PTR(ret);
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 8b31caa60b0a..d2df7cfbec06 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2875,14 +2875,10 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	}
 	ret = 1;
 done:
-	/*
-	 * we don't really know what they plan on doing with the path
-	 * from here on, so for now just mark it as blocking
-	 */
-	if (!p->leave_spinning)
-		btrfs_set_path_blocking(p);
 	if (ret < 0 && !p->skip_release_on_error)
 		btrfs_release_path(p);
+
+	/* path is supposed to be in blocking mode from now on. */
 	return ret;
 }
 
@@ -2987,11 +2983,10 @@ int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
 	}
 	ret = 1;
 done:
-	if (!p->leave_spinning)
-		btrfs_set_path_blocking(p);
 	if (ret < 0)
 		btrfs_release_path(p);
 
+	/* path is supposed to be in blocking mode from now on.*/
 	return ret;
 }
 
@@ -5628,7 +5623,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
 	struct btrfs_key key;
 	u32 nritems;
 	int ret;
-	int old_spinning = path->leave_spinning;
 	int next_rw_lock = 0;
 
 	nritems = btrfs_header_nritems(path->nodes[0]);
@@ -5643,7 +5637,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
 	btrfs_release_path(path);
 
 	path->keep_locks = 1;
-	path->leave_spinning = 1;
 
 	if (time_seq)
 		ret = btrfs_search_old_slot(root, &key, path, time_seq);
@@ -5780,9 +5773,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
 	ret = 0;
 done:
 	unlock_up(path, 0, 1, 0, NULL);
-	path->leave_spinning = old_spinning;
-	if (!old_spinning)
-		btrfs_set_path_blocking(path);
 
 	return ret;
 }
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1aeed3c0e949..e8bddf21b7f7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -339,7 +339,6 @@ struct btrfs_path {
 	unsigned int search_for_split:1;
 	unsigned int keep_locks:1;
 	unsigned int skip_locking:1;
-	unsigned int leave_spinning:1;
 	unsigned int search_commit_root:1;
 	unsigned int need_commit_sem:1;
 	unsigned int skip_release_on_error:1;
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index db9f45082c61..e6fbcdbc313e 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1138,7 +1138,6 @@ static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	block_rsv = trans->block_rsv;
 	trans->block_rsv = &fs_info->delayed_block_rsv;
@@ -1203,7 +1202,6 @@ int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
 		btrfs_release_delayed_node(delayed_node);
 		return -ENOMEM;
 	}
-	path->leave_spinning = 1;
 
 	block_rsv = trans->block_rsv;
 	trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
@@ -1248,7 +1246,6 @@ int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
 		ret = -ENOMEM;
 		goto trans_out;
 	}
-	path->leave_spinning = 1;
 
 	block_rsv = trans->block_rsv;
 	trans->block_rsv = &fs_info->delayed_block_rsv;
@@ -1317,7 +1314,6 @@ static void btrfs_async_run_delayed_root(struct btrfs_work *work)
 		if (!delayed_node)
 			break;
 
-		path->leave_spinning = 1;
 		root = delayed_node->root;
 
 		trans = btrfs_join_transaction(root);
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index a678b07fcf01..4f27d6ba2f1e 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -127,7 +127,6 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	btrfs_cpu_key_to_disk(&disk_key, location);
 
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 1f3755b3a37a..7f410edd92e4 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -245,7 +245,6 @@ static int btrfs_get_name(struct dentry *parent, char *name,
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	if (ino == BTRFS_FIRST_FREE_OBJECTID) {
 		key.objectid = BTRFS_I(inode)->root->root_key.objectid;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index de6f75f5547b..8d9ca923db93 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2116,7 +2116,6 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 
 	path->reada = READA_FORWARD;
-	path->leave_spinning = 1;
 	/* this will setup the path even if it fails to insert the back ref */
 	ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
 					   parent, root_objectid, owner,
@@ -2141,7 +2140,6 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	btrfs_release_path(path);
 
 	path->reada = READA_FORWARD;
-	path->leave_spinning = 1;
 	/* now insert the actual backref */
 	ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
 				    owner, offset, refs_to_add);
@@ -2251,7 +2249,6 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
 
 again:
 	path->reada = READA_FORWARD;
-	path->leave_spinning = 1;
 	ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
 	if (ret < 0) {
 		err = ret;
@@ -6700,7 +6697,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 
 	path->reada = READA_FORWARD;
-	path->leave_spinning = 1;
 
 	is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
 	BUG_ON(!is_data && refs_to_drop != 1);
@@ -6743,7 +6739,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 				goto out;
 			}
 			btrfs_release_path(path);
-			path->leave_spinning = 1;
 
 			key.objectid = bytenr;
 			key.type = BTRFS_EXTENT_ITEM_KEY;
@@ -7896,7 +7891,6 @@ static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
 				      ins, size);
 	if (ret) {
@@ -7985,7 +7979,6 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 		return -ENOMEM;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
 				      &extent_key, size);
 	if (ret) {
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 628f1aef34b0..481a4bbc49fd 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4444,7 +4444,6 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	start = round_down(start, btrfs_inode_sectorsize(inode));
 	len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index ba74827beb32..8e25953ed901 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -45,7 +45,6 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
 	file_key.offset = pos;
 	file_key.type = BTRFS_EXTENT_DATA_KEY;
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      sizeof(*item));
 	if (ret < 0)
@@ -598,7 +597,6 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
 		key.offset = end_byte - 1;
 		key.type = BTRFS_EXTENT_CSUM_KEY;
 
-		path->leave_spinning = 1;
 		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 		if (ret > 0) {
 			if (path->slots[0] == 0)
@@ -874,10 +872,8 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 	} else {
 		ins_size = csum_size;
 	}
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, root, path, &file_key,
 				      ins_size);
-	path->leave_spinning = 0;
 	if (ret < 0)
 		goto fail_unlock;
 	if (WARN_ON(ret != 0))
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index d6736595ec57..bccc33bb453c 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1188,8 +1188,6 @@ static int clear_free_space_tree(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
-
 	key.objectid = 0;
 	key.type = 0;
 	key.offset = 0;
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index a8956a3c9e05..97a7b4de1033 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -129,8 +129,6 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
-
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 	if (ret > 0)
 		ret = -ENOENT;
@@ -203,8 +201,6 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
-
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 	if (ret > 0) {
 		ret = -ENOENT;
@@ -278,7 +274,6 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(trans, root, path, &key,
 				      ins_len);
 	if (ret == -EEXIST) {
@@ -335,7 +330,6 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
 	path->skip_release_on_error = 1;
 	ret = btrfs_insert_empty_item(trans, root, path, &key,
 				      ins_len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9357a19d2bff..8b135a46835f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -191,7 +191,6 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 		key.type = BTRFS_EXTENT_DATA_KEY;
 
 		datasize = btrfs_file_extent_calc_inline_size(cur_size);
-		path->leave_spinning = 1;
 		ret = btrfs_insert_empty_item(trans, root, path, &key,
 					      datasize);
 		if (ret)
@@ -2236,7 +2235,6 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
 		ins.offset = file_pos;
 		ins.type = BTRFS_EXTENT_DATA_KEY;
 
-		path->leave_spinning = 1;
 		ret = btrfs_insert_empty_item(trans, root, path, &ins,
 					      sizeof(*fi));
 		if (ret)
@@ -2668,7 +2666,6 @@ static noinline int relink_extent_backref(struct btrfs_path *path,
 	key.type = BTRFS_EXTENT_DATA_KEY;
 	key.offset = start;
 
-	path->leave_spinning = 1;
 	if (merge) {
 		struct btrfs_file_extent_item *fi;
 		u64 extent_len;
@@ -2739,7 +2736,6 @@ static noinline int relink_extent_backref(struct btrfs_path *path,
 	ret = 1;
 out_free_path:
 	btrfs_release_path(path);
-	path->leave_spinning = 0;
 	btrfs_end_transaction(trans);
 out_unlock:
 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, lock_start, lock_end,
@@ -3833,7 +3829,6 @@ static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
 	ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
 				 1);
 	if (ret) {
@@ -3924,7 +3919,6 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	path->leave_spinning = 1;
 	di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
 				    name, name_len, -1);
 	if (IS_ERR(di)) {
@@ -4584,7 +4578,6 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 		goto out;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 	if (ret < 0)
 		goto out;
@@ -6300,7 +6293,6 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
 		goto fail;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
 	if (ret != 0)
 		goto fail_unlock;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d3a5d2a41e5f..1de051f529f9 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3899,7 +3899,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 		 * note the key will change type as we walk through the
 		 * tree.
 		 */
-		path->leave_spinning = 1;
 		ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
 				0, 0);
 		if (ret < 0)
@@ -3981,7 +3980,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 					   size);
 
 			btrfs_release_path(path);
-			path->leave_spinning = 0;
 
 			memcpy(&new_key, &key, sizeof(new_key));
 			new_key.objectid = btrfs_ino(BTRFS_I(inode));
@@ -4371,7 +4369,6 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
 		ret = -ENOMEM;
 		goto out;
 	}
-	path->leave_spinning = 1;
 
 	trans = btrfs_start_transaction(root, 1);
 	if (IS_ERR(trans)) {
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 4353bb69bb86..58e859593bbb 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -844,8 +844,6 @@ static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
 	if (!path)
 		return -ENOMEM;
 
-	path->leave_spinning = 1;
-
 	key.objectid = 0;
 	key.offset = 0;
 	key.type = 0;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6601c9aa5e35..4aa0b4f61ffd 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1015,7 +1015,6 @@ static char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
 		ret = -ENOMEM;
 		goto err;
 	}
-	path->leave_spinning = 1;
 
 	name = kmalloc(PATH_MAX, GFP_KERNEL);
 	if (!name) {
@@ -1143,7 +1142,6 @@ static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objec
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
-	path->leave_spinning = 1;
 
 	/*
 	 * Find the "default" dir item which points to the root item that we
diff --git a/fs/btrfs/tests/qgroup-tests.c b/fs/btrfs/tests/qgroup-tests.c
index 412b910b04cc..91233a0d4d62 100644
--- a/fs/btrfs/tests/qgroup-tests.c
+++ b/fs/btrfs/tests/qgroup-tests.c
@@ -36,7 +36,6 @@ static int insert_normal_tree_ref(struct btrfs_root *root, u64 bytenr,
 		return -ENOMEM;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_insert_empty_item(&trans, root, path, &ins, size);
 	if (ret) {
 		test_err("couldn't insert ref %d", ret);
@@ -86,7 +85,6 @@ static int add_tree_ref(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
 		return -ENOMEM;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
 	if (ret) {
 		test_err("couldn't find extent ref");
@@ -135,7 +133,6 @@ static int remove_extent_item(struct btrfs_root *root, u64 bytenr,
 		test_err("couldn't allocate path");
 		return -ENOMEM;
 	}
-	path->leave_spinning = 1;
 
 	ret = btrfs_search_slot(&trans, root, &key, path, -1, 1);
 	if (ret) {
@@ -170,7 +167,6 @@ static int remove_extent_ref(struct btrfs_root *root, u64 bytenr,
 		return -ENOMEM;
 	}
 
-	path->leave_spinning = 1;
 	ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
 	if (ret) {
 		test_err("couldn't find extent ref");
-- 
1.8.3.1