On Fri, Sep 20, 2013 at 05:05:08PM -0500, Mark Tinguely wrote:
> Commit f5ea1100 cleans up the disk to host conversions for
> node directory entries, but because a variable is reused in
> xfs_node_toosmall() the next node is not correctly found.
> If the original node is small enough (<= 3/8 of the node size),
> this change may incorrectly cause a node collapse when it should
> not. That will cause an assert in xfstest generic/319:
>
> Assertion failed: first <= last && last < BBTOB(bp->b_length),
> file: /root/newest/xfs/fs/xfs/xfs_trans_buf.c, line: 569
>
> Keep the original node header to get the correct forward node.
>
> Signed-off-by: Mark Tinguely <tinguely@xxxxxxx>
> ---
> fs/xfs/xfs_da_btree.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> Index: b/fs/xfs/xfs_da_btree.c
> ===================================================================
> --- a/fs/xfs/xfs_da_btree.c
> +++ b/fs/xfs/xfs_da_btree.c
> @@ -1163,6 +1163,7 @@ xfs_da3_node_toosmall(
> xfs_dablk_t blkno;
> struct xfs_buf *bp;
> struct xfs_da3_icnode_hdr nodehdr;
> + struct xfs_da3_icnode_hdr firstnhdr;
> int count;
> int forward;
> int error;
> @@ -1221,13 +1222,14 @@ xfs_da3_node_toosmall(
> count -= state->node_ents >> 2;
> count -= nodehdr.count;
>
> + firstnhdr = nodehdr;
> /* start with smaller blk num */
> forward = nodehdr.forw < nodehdr.back;
> for (i = 0; i < 2; forward = !forward, i++) {
> if (forward)
> - blkno = nodehdr.forw;
> + blkno = firstnhdr.forw;
> else
> - blkno = nodehdr.back;
> + blkno = firstnhdr.back;
> if (blkno == 0)
> continue;
> error = xfs_da3_node_read(state->args->trans, state->args->dp,
Yes, that definitely a bug, but I think that the change doesn't
scope correctly. The original node header doesn't need to be saved
like this - the node header decoded in the loop needs a loop-scope
variable. i.e.:
/* start with smaller blk num */
forward = nodehdr.forw < nodehdr.back;
for (i = 0; i < 2; forward = !forward, i++) {
+ struct xfs_da3_icnode_hdr thdr;
+
if (forward)
blkno = nodehdr.forw;
else
blkno = nodehdr.back;
if (blkno == 0)
continue;
error = xfs_da3_node_read(state->args->trans, state->args->dp,
blkno, -1, &bp, state->args->whichfork);
if (error)
return(error);
node = bp->b_addr;
- xfs_da3_node_hdr_from_disk(&nodehdr, node);
+ xfs_da3_node_hdr_from_disk(&thdr, node);
xfs_trans_brelse(state->args->trans, bp);
- if (count - nodehdr.count >= 0)
+ if (count - thdr.count >= 0)
break; /* fits with at least 25% to spare */
}
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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