From: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
To: <linux-btrfs@vger.kernel.org>
Cc: <nborisov@suse.com>
Subject: [PATCH] btrfs: delayed-ref: extract find_first_ref_head from find_ref_head
Date: Mon, 15 Oct 2018 14:25:38 +0800 [thread overview]
Message-ID: <20181015062538.30784-1-lufq.fnst@cn.fujitsu.com> (raw)
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.
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
---
fs/btrfs/delayed-ref.c | 45 +++++++++++++++++++++++-------------------
1 file changed, 25 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 6e8be384398e..a92f104cf06f 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -164,14 +164,28 @@ 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.
+ * match is found.
*/
-static struct btrfs_delayed_ref_head* find_ref_head(
+static struct btrfs_delayed_ref_head *find_ref_head(
struct btrfs_delayed_ref_root *dr, u64 bytenr,
bool return_bigger)
{
@@ -195,10 +209,9 @@ 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;
}
@@ -358,33 +371,25 @@ 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);
- if (!head)
- return NULL;
- } else if (!head && loop) {
- return NULL;
+ head = find_first_ref_head(delayed_refs);
}
+ if (!head)
+ 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,
--
2.19.1
next reply other threads:[~2018-10-15 6:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 6:25 Lu Fengqi [this message]
2018-10-15 6:51 ` [PATCH] btrfs: delayed-ref: extract find_first_ref_head from find_ref_head Nikolay Borisov
2018-10-17 17:21 ` David Sterba
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