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Commit 0a9df0df authored by Lu Fengqi's avatar Lu Fengqi Committed by David Sterba
Browse files

btrfs: delayed-ref: extract find_first_ref_head from find_ref_head 



The find_ref_head shouldn't return the first entry even if no exact match
is found. So move the hidden behavior to higher level.

Besides, remove the useless local variables in the btrfs_select_ref_head.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarLu Fengqi <lufq.fnst@cn.fujitsu.com>
[ reformat comment ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 5ce55557

fs/btrfs/delayed-ref.c

+27 −23
Original line number Diff line number Diff line
@@ -164,12 +164,25 @@ static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root, 
	return NULL;

}



static struct btrfs_delayed_ref_head *find_first_ref_head(

		struct btrfs_delayed_ref_root *dr)

{

	struct rb_node *n;

	struct btrfs_delayed_ref_head *entry;



	n = rb_first_cached(&dr->href_root);

	if (!n)

		return NULL;



	entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);



	return entry;

}



/*

 * find an head entry based on bytenr. This returns the delayed ref

 * head if it was able to find one, or NULL if nothing was in that spot.

 * If return_bigger is given, the next bigger entry is returned if no exact

 * match is found. But if no bigger one is found then the first node of the

 * ref head tree will be returned.

 * Find a head entry based on bytenr. This returns the delayed ref head if it

 * was able to find one, or NULL if nothing was in that spot.  If return_bigger

 * is given, the next bigger entry is returned if no exact match is found.

 */

static struct btrfs_delayed_ref_head *find_ref_head(

		struct btrfs_delayed_ref_root *dr, u64 bytenr,
@@ -195,10 +208,9 @@ static struct btrfs_delayed_ref_head* find_ref_head( 
		if (bytenr > entry->bytenr) {

			n = rb_next(&entry->href_node);

			if (!n)

				n = rb_first_cached(&dr->href_root);

				return NULL;

			entry = rb_entry(n, struct btrfs_delayed_ref_head,

					 href_node);

			return entry;

		}

		return entry;

	}
@@ -355,33 +367,25 @@ struct btrfs_delayed_ref_head *btrfs_select_ref_head( 
		struct btrfs_delayed_ref_root *delayed_refs)

{

	struct btrfs_delayed_ref_head *head;

	u64 start;

	bool loop = false;



again:

	start = delayed_refs->run_delayed_start;

	head = find_ref_head(delayed_refs, start, true);

	if (!head && !loop) {

	head = find_ref_head(delayed_refs, delayed_refs->run_delayed_start,

			     true);

	if (!head && delayed_refs->run_delayed_start != 0) {

		delayed_refs->run_delayed_start = 0;

		start = 0;

		loop = true;

		head = find_ref_head(delayed_refs, start, true);

		head = find_first_ref_head(delayed_refs);

	}

	if (!head)

		return NULL;

	} else if (!head && loop) {

		return NULL;

	}



	while (head->processing) {

		struct rb_node *node;



		node = rb_next(&head->href_node);

		if (!node) {

			if (loop)

			if (delayed_refs->run_delayed_start == 0)

				return NULL;

			delayed_refs->run_delayed_start = 0;

			start = 0;

			loop = true;

			goto again;

		}

		head = rb_entry(node, struct btrfs_delayed_ref_head,