On 08/31/2011 04:17 PM, Arne Jansen wrote:
> On 06.08.2011 10:35, Liu Bo wrote:
>> When btrfs recovers from a crash, it may hit the oops below:
>>
>> ------------[ cut here ]------------
>> kernel BUG at fs/btrfs/inode.c:4580!
>> [...]
>> RIP: 0010:[<ffffffffa03df251>] [<ffffffffa03df251>] btrfs_add_link+0x161/0x1c0 [btrfs]
>> [...]
>> Call Trace:
>> [<ffffffffa03e7b31>] ? btrfs_inode_ref_index+0x31/0x80 [btrfs]
>> [<ffffffffa04054e9>] add_inode_ref+0x319/0x3f0 [btrfs]
>> [<ffffffffa0407087>] replay_one_buffer+0x2c7/0x390 [btrfs]
>> [<ffffffffa040444a>] walk_down_log_tree+0x32a/0x480 [btrfs]
>> [<ffffffffa0404695>] walk_log_tree+0xf5/0x240 [btrfs]
>> [<ffffffffa0406cc0>] btrfs_recover_log_trees+0x250/0x350 [btrfs]
>> [<ffffffffa0406dc0>] ? btrfs_recover_log_trees+0x350/0x350 [btrfs]
>> [<ffffffffa03d18b2>] open_ctree+0x1442/0x17d0 [btrfs]
>> [...]
>>
>> This comes from that while replaying an inode ref item, we forget to
>> check those old conflicting DIR_ITEM and DIR_INDEX items in fs/file tree,
>> then we will come to conflict corners which lead to BUG_ON().
>
> Is this a workaround for an on-disk corruption or a bug fix for the
> log replay code? It sounds like the latter, but I ask to be sure :)
>
The latter one, for log replay when we recover from a btrfs crash.
thanks,
liubo
> -Arne
>
>> Signed-off-by: Liu Bo <liubo2009@xxxxxxxxxxxxxx>
>> ---
>> fs/btrfs/tree-log.c | 28 ++++++++++++++++++++++++----
>> 1 files changed, 24 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
>> index babee65..786639f 100644
>> --- a/fs/btrfs/tree-log.c
>> +++ b/fs/btrfs/tree-log.c
>> @@ -799,14 +799,15 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
>> struct extent_buffer *eb, int slot,
>> struct btrfs_key *key)
>> {
>> - struct inode *dir;
>> - int ret;
>> struct btrfs_inode_ref *ref;
>> + struct btrfs_dir_item *di;
>> + struct inode *dir;
>> struct inode *inode;
>> - char *name;
>> - int namelen;
>> unsigned long ref_ptr;
>> unsigned long ref_end;
>> + char *name;
>> + int namelen;
>> + int ret;
>> int search_done = 0;
>>
>> /*
>> @@ -909,6 +910,25 @@ again:
>> }
>> btrfs_release_path(path);
>>
>> + /* look for a conflicting sequence number */
>> + di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
>> + btrfs_inode_ref_index(eb, ref),
>> + name, namelen, 0);
>> + if (di && !IS_ERR(di)) {
>> + ret = drop_one_dir_item(trans, root, path, dir, di);
>> + BUG_ON(ret);
>> + }
>> + btrfs_release_path(path);
>> +
>> + /* look for a conflicing name */
>> + di = btrfs_lookup_dir_item(trans, root, path, btrfs_ino(dir),
>> + name, namelen, 0);
>> + if (di && !IS_ERR(di)) {
>> + ret = drop_one_dir_item(trans, root, path, dir, di);
>> + BUG_ON(ret);
>> + }
>> + btrfs_release_path(path);
>> +
>> insert:
>> /* insert our name */
>> ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
>
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