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Subject[PATCH 38/48] staging/lustre/lmv: fix duplicate directory entries
Date
From: Ned Bass <bass6@llnl.gov>

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>
---
drivers/staging/lustre/lustre/lmv/lmv_obd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/lustre/lustre/lmv/lmv_obd.c b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
index 9e68eea..11c8d64 100644
--- a/drivers/staging/lustre/lustre/lmv/lmv_obd.c
+++ b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
@@ -2157,7 +2157,7 @@ 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));
@@ -2191,6 +2191,7 @@ 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)
--
1.7.9.5


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