From 2192b0baea395274ffcd38ec70e284389e3c243d Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Wed, 5 Jul 2017 12:07:52 -0700 Subject: xfs: fix contiguous dquot chunk iteration livelock The patch below updated xfs_dq_get_next_id() to use the XFS iext lookup helpers to locate the next quota id rather than to seek for data in the quota file. The updated code fails to correctly handle the case where the quota inode might have contiguous chunks part of the same extent. In this case, the start block offset is calculated based on the next expected id but the extent lookup returns the same start offset as for the previous chunk. This causes the returned id to go backwards and livelocks the quota iteration. This problem is reproduced intermittently by generic/232. To handle this case, check whether the startoff from the extent lookup is behind the startoff calculated from the next quota id. If so, bump up got.br_startoff to the specific file offset that is expected to hold the next dquot chunk. Fixes: bda250dbaf39 ("xfs: rewrite xfs_dq_get_next_id using xfs_iext_lookup_extent") Signed-off-by: Brian Foster Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_dquot.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c index 8848b397e7a8..f89f7b5241e6 100644 --- a/fs/xfs/xfs_dquot.c +++ b/fs/xfs/xfs_dquot.c @@ -733,10 +733,15 @@ xfs_dq_get_next_id( return error; } - if (xfs_iext_lookup_extent(quotip, "ip->i_df, start, &idx, &got)) + if (xfs_iext_lookup_extent(quotip, "ip->i_df, start, &idx, &got)) { + /* contiguous chunk, bump startoff for the id calculation */ + if (got.br_startoff < start) + got.br_startoff = start; *id = got.br_startoff * mp->m_quotainfo->qi_dqperchunk; - else + } else { error = -ENOENT; + } + xfs_iunlock(quotip, lock_flags); return error; -- cgit v1.2.3