From 6103fb43fbc6d1caa78f26a1d0aa3d1a4525cea5 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 12 Feb 2014 15:07:52 +0000 Subject: Btrfs: remove unnecessary ref heads rb tree search When we didn't find the exact ref head we were looking for, if return_bigger != 0 we set a new search key to match either the next node after the last one we found or the first one in the ref heads rb tree, and then did another full tree search. For both cases this ended up being pointless as we would end up returning an entry we already had before repeating the search. Signed-off-by: Filipe David Borba Manana Signed-off-by: Josef Bacik --- fs/btrfs/delayed-ref.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/delayed-ref.c') diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index f3bff89eecf0..56cdfe988d69 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -205,7 +205,6 @@ find_ref_head(struct rb_root *root, u64 bytenr, struct btrfs_delayed_ref_head *entry; int cmp = 0; -again: n = root->rb_node; entry = NULL; while (n) { @@ -234,9 +233,9 @@ again: n = rb_first(root); entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node); - bytenr = entry->node.bytenr; - return_bigger = 0; - goto again; + if (last) + *last = entry; + return entry; } return entry; } -- cgit v1.2.3 From 85fdfdf6118dc00c2fcea8907815e48c98ee6c1d Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 12 Feb 2014 15:07:53 +0000 Subject: Btrfs: cleanup delayed-ref.c:find_ref_head() The argument last wasn't used, all callers supplied a NULL value for it. Also removed unnecessary intermediate storage of the result of key comparisons. Signed-off-by: Filipe David Borba Manana Signed-off-by: Josef Bacik --- fs/btrfs/delayed-ref.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) (limited to 'fs/btrfs/delayed-ref.c') diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 56cdfe988d69..2502ba5a3ac0 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -199,42 +199,30 @@ static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root, */ static struct btrfs_delayed_ref_head * find_ref_head(struct rb_root *root, u64 bytenr, - struct btrfs_delayed_ref_head **last, int return_bigger) + int return_bigger) { struct rb_node *n; struct btrfs_delayed_ref_head *entry; - int cmp = 0; n = root->rb_node; entry = NULL; while (n) { entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node); - if (last) - *last = entry; if (bytenr < entry->node.bytenr) - cmp = -1; - else if (bytenr > entry->node.bytenr) - cmp = 1; - else - cmp = 0; - - if (cmp < 0) n = n->rb_left; - else if (cmp > 0) + else if (bytenr > entry->node.bytenr) n = n->rb_right; else return entry; } if (entry && return_bigger) { - if (cmp > 0) { + if (bytenr > entry->node.bytenr) { n = rb_next(&entry->href_node); if (!n) n = rb_first(root); entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node); - if (last) - *last = entry; return entry; } return entry; @@ -414,12 +402,12 @@ btrfs_select_ref_head(struct btrfs_trans_handle *trans) again: start = delayed_refs->run_delayed_start; - head = find_ref_head(&delayed_refs->href_root, start, NULL, 1); + head = find_ref_head(&delayed_refs->href_root, start, 1); if (!head && !loop) { delayed_refs->run_delayed_start = 0; start = 0; loop = true; - head = find_ref_head(&delayed_refs->href_root, start, NULL, 1); + head = find_ref_head(&delayed_refs->href_root, start, 1); if (!head) return NULL; } else if (!head && loop) { @@ -897,7 +885,7 @@ btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr) struct btrfs_delayed_ref_root *delayed_refs; delayed_refs = &trans->transaction->delayed_refs; - return find_ref_head(&delayed_refs->href_root, bytenr, NULL, 0); + return find_ref_head(&delayed_refs->href_root, bytenr, 0); } void btrfs_delayed_ref_exit(void) -- cgit v1.2.3 From 21543baddcdbaa49db5ac8766ae564381e7c64d9 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Fri, 14 Mar 2014 20:55:01 +0000 Subject: Btrfs: fix race when updating existing ref head While we update an existing ref head's extent_op, we're not holding its spinlock, so while we're updating its extent_op contents (key, flags) we can have a task running __btrfs_run_delayed_refs() that holds the ref head's lock and sets its extent_op to NULL right after the task updating the ref head just checked its extent_op was not NULL. Signed-off-by: Filipe David Borba Manana Signed-off-by: Chris Mason --- fs/btrfs/delayed-ref.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/delayed-ref.c') diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index 2502ba5a3ac0..31299646024d 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -495,6 +495,7 @@ update_existing_head_ref(struct btrfs_delayed_ref_node *existing, ref = btrfs_delayed_node_to_head(update); BUG_ON(existing_ref->is_data != ref->is_data); + spin_lock(&existing_ref->lock); if (ref->must_insert_reserved) { /* if the extent was freed and then * reallocated before the delayed ref @@ -536,7 +537,6 @@ update_existing_head_ref(struct btrfs_delayed_ref_node *existing, * only need the lock for this case cause we could be processing it * currently, for refs we just added we know we're a-ok. */ - spin_lock(&existing_ref->lock); existing->ref_mod += update->ref_mod; spin_unlock(&existing_ref->lock); } -- cgit v1.2.3