From 0a9df0df17a011fa4d17277a8c8dd662668c6426 Mon Sep 17 00:00:00 2001 From: Lu Fengqi Date: Mon, 15 Oct 2018 14:25:38 +0800 Subject: [PATCH] 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: Nikolay Borisov Signed-off-by: Lu Fengqi [ reformat comment ] Signed-off-by: David Sterba --- fs/btrfs/delayed-ref.c | 50 +++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 23 deletions(-) diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 5149165b49a4..9301b3ad9217 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -164,14 +164,27 @@ 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( +static struct btrfs_delayed_ref_head *find_ref_head( struct btrfs_delayed_ref_root *dr, u64 bytenr, bool return_bigger) { @@ -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); - 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, -- 2.30.2