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btrfs: don't create or leak aliased root while cleaning up orphans

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commit 909c3a22da (Btrfs: fix loading of orphan roots leading to BUG_ON)
avoids the BUG_ON but can add an aliased root to the dead_roots list or
leak the root.

Since we've already been loading roots into the radix tree, we should
use it before looking the root up on disk.

Cc: <stable@vger.kernel.org> # 4.5
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Jeff Mahoney 2016-08-17 21:58:33 -04:00 committed by Chris Mason
parent 187ee58c62
commit 35bbb97fc8
3 changed files with 22 additions and 11 deletions
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4
fs/btrfs/disk-io.c
View file

@ -1624,8 +1624,8 @@ int btrfs_init_fs_root(struct btrfs_root *root)
return ret;
}
static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
u64 root_id)
struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
u64 root_id)
{
struct btrfs_root *root;

2
fs/btrfs/disk-io.h
View file

@ -68,6 +68,8 @@ struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
struct btrfs_key *location);
int btrfs_init_fs_root(struct btrfs_root *root);
struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
u64 root_id);
int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
struct btrfs_root *root);
void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);

27
fs/btrfs/root-tree.c
View file

@ -272,6 +272,23 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
root_key.objectid = key.offset;
key.offset++;
/*
* The root might have been inserted already, as before we look
* for orphan roots, log replay might have happened, which
* triggers a transaction commit and qgroup accounting, which
* in turn reads and inserts fs roots while doing backref
* walking.
*/
root = btrfs_lookup_fs_root(tree_root->fs_info,
root_key.objectid);
if (root) {
WARN_ON(!test_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
&root->state));
if (btrfs_root_refs(&root->root_item) == 0)
btrfs_add_dead_root(root);
continue;
}
root = btrfs_read_fs_root(tree_root, &root_key);
err = PTR_ERR_OR_ZERO(root);
if (err && err != -ENOENT) {
@ -310,16 +327,8 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root)
set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
err = btrfs_insert_fs_root(root->fs_info, root);
/*
* The root might have been inserted already, as before we look
* for orphan roots, log replay might have happened, which
* triggers a transaction commit and qgroup accounting, which
* in turn reads and inserts fs roots while doing backref
* walking.
*/
if (err == -EEXIST)
err = 0;
if (err) {
BUG_ON(err == -EEXIST);
btrfs_free_fs_root(root);
break;
}