staging/lustre/lmv: fix duplicate directory entries

Previously, I accidentally introduced a new way for duplicate
directory entries to be returned from readdir().  That patch fails
to properly decrement the nlupgs counter when breaking out of the
inner-for loop.  This accounting error causes an extra iteration
of the inner-for loop when processing the next cfs page and a bad
ldp_hash_end value is then saved in the lu_dirpage.  To fix this,
always decrement the nlupgs counter on entry into the inner loop.

Note: this bug only affects architectures with > 4k-sized pages, e.g.
PowerPC.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3182
Lustre-change: http://review.whamcloud.com/6405
Signed-off-by: Ned Bass <bass6@llnl.gov>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Bobi Jam <bobijam@gmail.com>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/lmv/lmv_obd.c b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
index d10f7fc553d3be5f9ce69894aa85c90e7e2fe709..5bd952a6dd653a8b158f85df4a382c9efa5ff3f7 100644 (file)
--- a/drivers/staging/lustre/lustre/lmv/lmv_obd.c
+++ b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
@@ -1959,7 +1959,7 @@ static void lmv_adjust_dirpages(struct page **pages, int ncfspgs, int nlupgs)
                __u64                   hash_end = dp->ldp_hash_end;
                __u32                   flags = dp->ldp_flags;
 
-               for (; nlupgs > 1; nlupgs--) {
+               while (--nlupgs > 0) {
                        ent = lu_dirent_start(dp);
                        for (end_dirent = ent; ent != NULL;
                             end_dirent = ent, ent = lu_dirent_next(ent));
@@ -1993,6 +1993,7 @@ static void lmv_adjust_dirpages(struct page **pages, int ncfspgs, int nlupgs)
 
                kunmap(pages[i]);
        }
+       LASSERTF(nlupgs == 0, "left = %d", nlupgs);
 }
 #else
 #define lmv_adjust_dirpages(pages, ncfspgs, nlupgs) do {} while (0)