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 :)
-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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