nfs: fix DIO good bytes calculation
For direct read that has IO size larger than rsize, we'll split
it into several READ requests and nfs_direct_good_bytes() would
count completed bytes incorrectly by eating last zero count reply.
Fix it by handling mirror and non-mirror cases differently such that
we only count mirrored writes differently.
This fixes 5fadeb47("nfs: count DIO good bytes correctly with mirroring").
Reported-by: Jean Spector <jean@primarydata.com>
Cc: <stable@vger.kernel.org> # v3.19+
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 018a06a..e97a67e 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -131,20 +131,25 @@
WARN_ON_ONCE(hdr->pgio_mirror_idx >= dreq->mirror_count);
- count = dreq->mirrors[hdr->pgio_mirror_idx].count;
- if (count + dreq->io_start < hdr->io_start + hdr->good_bytes) {
- count = hdr->io_start + hdr->good_bytes - dreq->io_start;
- dreq->mirrors[hdr->pgio_mirror_idx].count = count;
+ if (dreq->mirror_count == 1) {
+ dreq->mirrors[hdr->pgio_mirror_idx].count += hdr->good_bytes;
+ dreq->count += hdr->good_bytes;
+ } else {
+ /* mirrored writes */
+ count = dreq->mirrors[hdr->pgio_mirror_idx].count;
+ if (count + dreq->io_start < hdr->io_start + hdr->good_bytes) {
+ count = hdr->io_start + hdr->good_bytes - dreq->io_start;
+ dreq->mirrors[hdr->pgio_mirror_idx].count = count;
+ }
+ /* update the dreq->count by finding the minimum agreed count from all
+ * mirrors */
+ count = dreq->mirrors[0].count;
+
+ for (i = 1; i < dreq->mirror_count; i++)
+ count = min(count, dreq->mirrors[i].count);
+
+ dreq->count = count;
}
-
- /* update the dreq->count by finding the minimum agreed count from all
- * mirrors */
- count = dreq->mirrors[0].count;
-
- for (i = 1; i < dreq->mirror_count; i++)
- count = min(count, dreq->mirrors[i].count);
-
- dreq->count = count;
}
/*