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authorJosef Bacik <jbacik@fusionio.com>2013-07-30 16:30:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-13 15:42:50 -0700
commit027a76bf3d56c7d7ef17aadfaec826a5d33f28f3 (patch)
tree159e664043c67f5535a4bada7aa0123857f66af2
parent5df7085368ce132b9d93e5cff406df4684615419 (diff)
Btrfs: change how we queue blocks for backref checking
commit b6c60c8018c4e9beb2f83fc82c09f9d033766571 upstream. Previously we only added blocks to the list to have their backrefs checked if the level of the block is right above the one we are searching for. This is because we want to make sure we don't add the entire path up to the root to the lists to make sure we process things one at a time. This assumes that if any blocks in the path to the root are going to be not checked (shared in other words) then they will be in the level right above the current block on up. This isn't quite right though since we can have blocks higher up the list that are shared because they are attached to a reloc root. But we won't add this block to be checked and then later on we will BUG_ON(!upper->checked). So instead keep track of wether or not we've queued a block to be checked in this current search, and if we haven't go ahead and queue it to be checked. This patch fixed the panic I was seeing where we BUG_ON(!upper->checked). Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/btrfs/relocation.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 646ee21bb035..92841a73c0e3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -684,6 +684,7 @@ struct backref_node *build_backref_tree(struct reloc_control *rc,
int cowonly;
int ret;
int err = 0;
+ bool need_check = true;
path1 = btrfs_alloc_path();
path2 = btrfs_alloc_path();
@@ -906,6 +907,7 @@ again:
cur->bytenr);
lower = cur;
+ need_check = true;
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path2->nodes[level]) {
BUG_ON(btrfs_root_bytenr(&root->root_item) !=
@@ -949,14 +951,12 @@ again:
/*
* add the block to pending list if we
- * need check its backrefs. only block
- * at 'cur->level + 1' is added to the
- * tail of pending list. this guarantees
- * we check backrefs from lower level
- * blocks to upper level blocks.
+ * need check its backrefs, we only do this once
+ * while walking up a tree as we will catch
+ * anything else later on.
*/
- if (!upper->checked &&
- level == cur->level + 1) {
+ if (!upper->checked && need_check) {
+ need_check = false;
list_add_tail(&edge->list[UPPER],
&list);
} else