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authorWang Shilong <wangsl.fnst@cn.fujitsu.com>2013-12-11 12:29:51 +0100
committerChris Mason <clm@fb.com>2013-12-12 16:12:20 +0100
commitc974c4642fee8c58239c7753d0bf548b23799923 (patch)
treea671a832030045d977a38ec25a84044fcbca5d1e /fs
parentBtrfs: don't miss skinny extent items on delayed ref head contention (diff)
downloadlinux-c974c4642fee8c58239c7753d0bf548b23799923.tar.xz
linux-c974c4642fee8c58239c7753d0bf548b23799923.zip
Btrfs: fix an oops when doing balance relocation
I hit an oops when inserting reloc root into @reloc_root_tree(it can be easily triggered when forcing cow for relocation root) [ 866.494539] [<ffffffffa0499579>] btrfs_init_reloc_root+0x79/0xb0 [btrfs] [ 866.495321] [<ffffffffa044c240>] record_root_in_trans+0xb0/0x110 [btrfs] [ 866.496109] [<ffffffffa044d758>] btrfs_record_root_in_trans+0x48/0x80 [btrfs] [ 866.496908] [<ffffffffa0494da8>] select_reloc_root+0xa8/0x210 [btrfs] [ 866.497703] [<ffffffffa0495c8a>] do_relocation+0x16a/0x540 [btrfs] This is because reloc root inserted into @reloc_root_tree is not within one transaction,reloc root may be cowed and root block bytenr will be reused then oops happens.We should update reloc root in @reloc_root_tree when cow reloc root node, fix it. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/relocation.c70
1 files changed, 47 insertions, 23 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index ce459a7cb16d..7cdc76007c6c 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1264,10 +1264,10 @@ static int __must_check __add_reloc_root(struct btrfs_root *root)
}
/*
- * helper to update/delete the 'address of tree root -> reloc tree'
+ * helper to delete the 'address of tree root -> reloc tree'
* mapping
*/
-static int __update_reloc_root(struct btrfs_root *root, int del)
+static void __del_reloc_root(struct btrfs_root *root)
{
struct rb_node *rb_node;
struct mapping_node *node = NULL;
@@ -1275,7 +1275,7 @@ static int __update_reloc_root(struct btrfs_root *root, int del)
spin_lock(&rc->reloc_root_tree.lock);
rb_node = tree_search(&rc->reloc_root_tree.rb_root,
- root->commit_root->start);
+ root->node->start);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
@@ -1283,23 +1283,45 @@ static int __update_reloc_root(struct btrfs_root *root, int del)
spin_unlock(&rc->reloc_root_tree.lock);
if (!node)
- return 0;
+ return;
BUG_ON((struct btrfs_root *)node->data != root);
- if (!del) {
- spin_lock(&rc->reloc_root_tree.lock);
- node->bytenr = root->node->start;
- rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
- node->bytenr, &node->rb_node);
- spin_unlock(&rc->reloc_root_tree.lock);
- if (rb_node)
- backref_tree_panic(rb_node, -EEXIST, node->bytenr);
- } else {
- spin_lock(&root->fs_info->trans_lock);
- list_del_init(&root->root_list);
- spin_unlock(&root->fs_info->trans_lock);
- kfree(node);
+ spin_lock(&root->fs_info->trans_lock);
+ list_del_init(&root->root_list);
+ spin_unlock(&root->fs_info->trans_lock);
+ kfree(node);
+}
+
+/*
+ * helper to update the 'address of tree root -> reloc tree'
+ * mapping
+ */
+static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
+{
+ struct rb_node *rb_node;
+ struct mapping_node *node = NULL;
+ struct reloc_control *rc = root->fs_info->reloc_ctl;
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ rb_node = tree_search(&rc->reloc_root_tree.rb_root,
+ root->node->start);
+ if (rb_node) {
+ node = rb_entry(rb_node, struct mapping_node, rb_node);
+ rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
}
+ spin_unlock(&rc->reloc_root_tree.lock);
+
+ if (!node)
+ return 0;
+ BUG_ON((struct btrfs_root *)node->data != root);
+
+ spin_lock(&rc->reloc_root_tree.lock);
+ node->bytenr = new_bytenr;
+ rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
+ node->bytenr, &node->rb_node);
+ spin_unlock(&rc->reloc_root_tree.lock);
+ if (rb_node)
+ backref_tree_panic(rb_node, -EEXIST, node->bytenr);
return 0;
}
@@ -1420,7 +1442,6 @@ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
{
struct btrfs_root *reloc_root;
struct btrfs_root_item *root_item;
- int del = 0;
int ret;
if (!root->reloc_root)
@@ -1432,11 +1453,9 @@ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
if (root->fs_info->reloc_ctl->merge_reloc_tree &&
btrfs_root_refs(root_item) == 0) {
root->reloc_root = NULL;
- del = 1;
+ __del_reloc_root(reloc_root);
}
- __update_reloc_root(reloc_root, del);
-
if (reloc_root->commit_root != reloc_root->node) {
btrfs_set_root_node(root_item, reloc_root->node);
free_extent_buffer(reloc_root->commit_root);
@@ -2287,7 +2306,7 @@ void free_reloc_roots(struct list_head *list)
while (!list_empty(list)) {
reloc_root = list_entry(list->next, struct btrfs_root,
root_list);
- __update_reloc_root(reloc_root, 1);
+ __del_reloc_root(reloc_root);
free_extent_buffer(reloc_root->node);
free_extent_buffer(reloc_root->commit_root);
kfree(reloc_root);
@@ -2332,7 +2351,7 @@ again:
ret = merge_reloc_root(rc, root);
if (ret) {
- __update_reloc_root(reloc_root, 1);
+ __del_reloc_root(reloc_root);
free_extent_buffer(reloc_root->node);
free_extent_buffer(reloc_root->commit_root);
kfree(reloc_root);
@@ -4522,6 +4541,11 @@ int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ if (buf == root->node)
+ __update_reloc_root(root, cow->start);
+ }
+
level = btrfs_header_level(buf);
if (btrfs_header_generation(buf) <=
btrfs_root_last_snapshot(&root->root_item))