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nfs: fix DIO good bytes calculation

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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>
This commit is contained in:
Peng Tao 2015-04-09 23:02:16 +08:00 committed by Trond Myklebust
parent ea96d1ecbe
commit 1ccbad9f9f
1 changed files with 18 additions and 13 deletions
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31
fs/nfs/direct.c
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@ -131,20 +131,25 @@ nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr)
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;
}
/*