This is a note to let you know that I've just added the patch titled
Btrfs: cleanup error handling in build_backref_tree
to the 3.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-cleanup-error-handling-in-build_backref_tree.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 75bfb9aff45e44625260f52a5fd581b92ace3e62 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@xxxxxx>
Date: Fri, 19 Sep 2014 10:40:00 -0400
Subject: Btrfs: cleanup error handling in build_backref_tree
From: Josef Bacik <jbacik@xxxxxx>
commit 75bfb9aff45e44625260f52a5fd581b92ace3e62 upstream.
When balance panics it tends to panic in the
BUG_ON(!upper->checked);
test, because it means it couldn't build the backref tree properly. This is
annoying to users and frankly a recoverable error, nothing in this function is
actually fatal since it is just an in-memory building of the backrefs for a
given bytenr. So go through and change all the BUG_ON()'s to ASSERT()'s, and
fix the BUG_ON(!upper->checked) thing to just return an error.
This patch also fixes the error handling so it tears down the work we've done
properly. This code was horribly broken since we always just panic'ed instead
of actually erroring out, so it needed to be completely re-worked. With this
patch my broken image no longer panics when I mount it. Thanks,
Signed-off-by: Josef Bacik <jbacik@xxxxxx>
Signed-off-by: Chris Mason <clm@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/relocation.c | 88 +++++++++++++++++++++++++++++++++-----------------
1 file changed, 59 insertions(+), 29 deletions(-)
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -736,7 +736,8 @@ again:
err = ret;
goto out;
}
- BUG_ON(!ret || !path1->slots[0]);
+ ASSERT(ret);
+ ASSERT(path1->slots[0]);
path1->slots[0]--;
@@ -746,10 +747,10 @@ again:
* the backref was added previously when processing
* backref of type BTRFS_TREE_BLOCK_REF_KEY
*/
- BUG_ON(!list_is_singular(&cur->upper));
+ ASSERT(list_is_singular(&cur->upper));
edge = list_entry(cur->upper.next, struct backref_edge,
list[LOWER]);
- BUG_ON(!list_empty(&edge->list[UPPER]));
+ ASSERT(list_empty(&edge->list[UPPER]));
exist = edge->node[UPPER];
/*
* add the upper level block to pending list if we need
@@ -831,7 +832,7 @@ again:
cur->cowonly = 1;
}
#else
- BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
+ ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
#endif
if (key.objectid == key.offset) {
@@ -840,7 +841,7 @@ again:
* backref of this type.
*/
root = find_reloc_root(rc, cur->bytenr);
- BUG_ON(!root);
+ ASSERT(root);
cur->root = root;
break;
}
@@ -868,7 +869,7 @@ again:
} else {
upper = rb_entry(rb_node, struct backref_node,
rb_node);
- BUG_ON(!upper->checked);
+ ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
}
list_add_tail(&edge->list[LOWER], &cur->upper);
@@ -892,7 +893,7 @@ again:
if (btrfs_root_level(&root->root_item) == cur->level) {
/* tree root */
- BUG_ON(btrfs_root_bytenr(&root->root_item) !=
+ ASSERT(btrfs_root_bytenr(&root->root_item) ==
cur->bytenr);
if (should_ignore_root(root))
list_add(&cur->list, &useless);
@@ -927,7 +928,7 @@ again:
need_check = true;
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path2->nodes[level]) {
- BUG_ON(btrfs_root_bytenr(&root->root_item) !=
+ ASSERT(btrfs_root_bytenr(&root->root_item) ==
lower->bytenr);
if (should_ignore_root(root))
list_add(&lower->list, &useless);
@@ -982,7 +983,7 @@ again:
} else {
upper = rb_entry(rb_node, struct backref_node,
rb_node);
- BUG_ON(!upper->checked);
+ ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
if (!upper->owner)
upper->owner = btrfs_header_owner(eb);
@@ -1026,7 +1027,7 @@ next:
* everything goes well, connect backref nodes and insert backref nodes
* into the cache.
*/
- BUG_ON(!node->checked);
+ ASSERT(node->checked);
cowonly = node->cowonly;
if (!cowonly) {
rb_node = tree_insert(&cache->rb_root, node->bytenr,
@@ -1062,8 +1063,21 @@ next:
continue;
}
- BUG_ON(!upper->checked);
- BUG_ON(cowonly != upper->cowonly);
+ if (!upper->checked) {
+ /*
+ * Still want to blow up for developers since this is a
+ * logic bug.
+ */
+ ASSERT(0);
+ err = -EINVAL;
+ goto out;
+ }
+ if (cowonly != upper->cowonly) {
+ ASSERT(0);
+ err = -EINVAL;
+ goto out;
+ }
+
if (!cowonly) {
rb_node = tree_insert(&cache->rb_root, upper->bytenr,
&upper->rb_node);
@@ -1086,7 +1100,7 @@ next:
while (!list_empty(&useless)) {
upper = list_entry(useless.next, struct backref_node, list);
list_del_init(&upper->list);
- BUG_ON(!list_empty(&upper->upper));
+ ASSERT(list_empty(&upper->upper));
if (upper == node)
node = NULL;
if (upper->lowest) {
@@ -1119,29 +1133,45 @@ out:
if (err) {
while (!list_empty(&useless)) {
lower = list_entry(useless.next,
- struct backref_node, upper);
- list_del_init(&lower->upper);
+ struct backref_node, list);
+ list_del_init(&lower->list);
}
- upper = node;
- INIT_LIST_HEAD(&list);
- while (upper) {
- if (RB_EMPTY_NODE(&upper->rb_node)) {
- list_splice_tail(&upper->upper, &list);
- free_backref_node(cache, upper);
- }
-
- if (list_empty(&list))
- break;
-
- edge = list_entry(list.next, struct backref_edge,
- list[LOWER]);
+ while (!list_empty(&list)) {
+ edge = list_first_entry(&list, struct backref_edge,
+ list[UPPER]);
+ list_del(&edge->list[UPPER]);
list_del(&edge->list[LOWER]);
+ lower = edge->node[LOWER];
upper = edge->node[UPPER];
free_backref_edge(cache, edge);
+
+ /*
+ * Lower is no longer linked to any upper backref nodes
+ * and isn't in the cache, we can free it ourselves.
+ */
+ if (list_empty(&lower->upper) &&
+ RB_EMPTY_NODE(&lower->rb_node))
+ list_add(&lower->list, &useless);
+
+ if (!RB_EMPTY_NODE(&upper->rb_node))
+ continue;
+
+ /* Add this guy's upper edges to the list to proces */
+ list_for_each_entry(edge, &upper->upper, list[LOWER])
+ list_add_tail(&edge->list[UPPER], &list);
+ if (list_empty(&upper->upper))
+ list_add(&upper->list, &useless);
+ }
+
+ while (!list_empty(&useless)) {
+ lower = list_entry(useless.next,
+ struct backref_node, list);
+ list_del_init(&lower->list);
+ free_backref_node(cache, lower);
}
return ERR_PTR(err);
}
- BUG_ON(node && node->detached);
+ ASSERT(!node || !node->detached);
return node;
}
Patches currently in stable-queue which might be from jbacik@xxxxxx are
queue-3.17/btrfs-fix-build_backref_tree-issue-with-multiple-shared-blocks.patch
queue-3.17/btrfs-try-not-to-enospc-on-log-replay.patch
queue-3.17/btrfs-don-t-do-async-reclaim-during-log-replay.patch
queue-3.17/btrfs-cleanup-error-handling-in-build_backref_tree.patch
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