From 30265117ee1e23fa91920f337a3ea91207f700dc Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 6 Jun 2014 16:06:37 +1000 Subject: [PATCH] xfs: Fix rounding in xfs_alloc_fix_len() Rounding in xfs_alloc_fix_len() is wrong. As the comment states, the result should be a number of a form (k*prod+mod) however due to sign mistake the result is different. As a result allocations on raid arrays could be misaligned in some cases. This also seems to fix occasional assertion failure: XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0) in xfs_alloc_ag_vextent_size(). Also add an assertion that the result of xfs_alloc_fix_len() is of expected form. Signed-off-by: Jan Kara Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- fs/xfs/xfs_alloc.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c index 077c3417a54e..d43813267a80 100644 --- a/fs/xfs/xfs_alloc.c +++ b/fs/xfs/xfs_alloc.c @@ -257,16 +257,14 @@ xfs_alloc_fix_len( k = rlen % args->prod; if (k == args->mod) return; - if (k > args->mod) { - if ((int)(rlen = rlen - k - args->mod) < (int)args->minlen) - return; - } else { - if ((int)(rlen = rlen - args->prod - (args->mod - k)) < - (int)args->minlen) - return; - } - ASSERT(rlen >= args->minlen); - ASSERT(rlen <= args->maxlen); + if (k > args->mod) + rlen = rlen - (k - args->mod); + else + rlen = rlen - args->prod + (args->mod - k); + if ((int)rlen < (int)args->minlen) + return; + ASSERT(rlen >= args->minlen && rlen <= args->maxlen); + ASSERT(rlen % args->prod == args->mod); args->len = rlen; }