On 10/30/18 12:20 PM, Darrick J. Wong wrote:
> On Tue, Oct 30, 2018 at 10:20:37PM +1100, Dave Chinner wrote:
>> This reverts commit 67a79e2cc9320aaf269cd00e9c8d16892931886d.
>>
>> A root LEAFN block can exist in a directory. When we convert from
>> leaf format (LEAF1 - internal free list) to node format (LEAFN -
>> external free list) the only change to the single root leaf block is
>> that it's magic number is changed from LEAF1 to LEAFN.
>>
>> We don't actually end up with DA nodes in the tree until the LEAFN
>> node is split, and that requires a couple more dirents to be added
>> to the directory to fill the LEAFN block up completely. Then it will
>> split and create a DA node root block pointing to multiple LEAFN
>> leaf blocks.
>>
>> Hence restore the old behaviour where we skip the DA node tree
>> rebuild if there is a LEAFN root block found as there is no tree to
>> rebuild.
>
> The trouble with reverting the patch is that xfs_repair goes back to
> tripping over an assertion in release_da_cursor_int if the reason why
> we got bno == 0 is that the directory has a da btree block with
> nbtree[0].before pointing to zero.
>
> Will post a better fix + regression tests for both issues shortly.
Well let's discuss pros/cons & risks/rewards on that, I'm semi-inclined
to just revert it for 4.19 and fix it properly in 4.20, because I don't think
it's ever been seen in the wild...?
-eric
> --D
>
>> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
>> ---
>> repair/dir2.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/repair/dir2.c b/repair/dir2.c
>> index 3374ae722bf9..ba5763ed3d26 100644
>> --- a/repair/dir2.c
>> +++ b/repair/dir2.c
>> @@ -1242,11 +1242,11 @@ process_node_dir2(
>> return 1;
>>
>> /*
>> - * Directories with a root marked XFS_DIR2_LEAFN_MAGIC are corrupt
>> + * Skip directories with a root marked XFS_DIR2_LEAFN_MAGIC
>> */
>> if (bno == 0) {
>> - err_release_da_cursor(mp, &da_cursor, 0);
>> - return 1;
>> + release_da_cursor(mp, &da_cursor, 0);
>> + return 0;
>> } else {
>> /*
>> * Now pass cursor and bno into leaf-block processing routine.
>> --
>> 2.19.1
>>
>
