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nfs: mirroring support for direct io

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The current mirroring code only notices short writes to the first
mirror. This patch keeps per-mirror byte counts and only considers
a byte to be written once all mirrors report so.

Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
This commit is contained in:
Weston Andros Adamson 2014-09-19 12:48:33 -04:00 committed by Tom Haynes
parent a7d42ddb30
commit 0a00b77b33
1 changed files with 57 additions and 14 deletions
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71
fs/nfs/direct.c
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@ -66,6 +66,10 @@ static struct kmem_cache *nfs_direct_cachep;
/*
* This represents a set of asynchronous requests that we're waiting on
*/
struct nfs_direct_mirror {
ssize_t count;
};
struct nfs_direct_req {
struct kref kref; /* release manager */
@ -78,6 +82,10 @@ struct nfs_direct_req {
/* completion state */
atomic_t io_count; /* i/os we're waiting for */
spinlock_t lock; /* protect completion state */
struct nfs_direct_mirror mirrors[NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX];
int mirror_count;
ssize_t count, /* bytes actually processed */
bytes_left, /* bytes left to be sent */
error; /* any reported error */
@ -108,6 +116,29 @@ static inline int put_dreq(struct nfs_direct_req *dreq)
return atomic_dec_and_test(&dreq->io_count);
}
static void
nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr)
{
int i;
ssize_t count;
WARN_ON_ONCE(hdr->pgio_mirror_idx >= dreq->mirror_count);
dreq->mirrors[hdr->pgio_mirror_idx].count += hdr->good_bytes;
if (hdr->pgio_mirror_idx == 0)
dreq->count += hdr->good_bytes;
/* 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;
}
/*
* nfs_direct_select_verf - select the right verifier
* @dreq - direct request possibly spanning multiple servers
@ -241,6 +272,18 @@ void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
cinfo->completion_ops = &nfs_direct_commit_completion_ops;
}
static inline void nfs_direct_setup_mirroring(struct nfs_direct_req *dreq,
struct nfs_pageio_descriptor *pgio,
struct nfs_page *req)
{
int mirror_count = 1;
if (pgio->pg_ops->pg_get_mirror_count)
mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
dreq->mirror_count = mirror_count;
}
static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
{
struct nfs_direct_req *dreq;
@ -255,6 +298,7 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
INIT_LIST_HEAD(&dreq->mds_cinfo.list);
dreq->verf.committed = NFS_INVALID_STABLE_HOW; /* not set yet */
INIT_WORK(&dreq->work, nfs_direct_write_schedule_work);
dreq->mirror_count = 1;
spin_lock_init(&dreq->lock);
return dreq;
@ -360,14 +404,9 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
spin_lock(&dreq->lock);
if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0))
dreq->error = hdr->error;
else {
/*
* FIXME: right now this only accounts for bytes written
* to the first mirror
*/
if (hdr->pgio_mirror_idx == 0)
dreq->count += hdr->good_bytes;
}
else
nfs_direct_good_bytes(dreq, hdr);
spin_unlock(&dreq->lock);
while (!list_empty(&hdr->pages)) {
@ -598,17 +637,23 @@ static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
LIST_HEAD(reqs);
struct nfs_commit_info cinfo;
LIST_HEAD(failed);
int i;
nfs_init_cinfo_from_dreq(&cinfo, dreq);
nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
dreq->count = 0;
for (i = 0; i < dreq->mirror_count; i++)
dreq->mirrors[i].count = 0;
get_dreq(dreq);
nfs_pageio_init_write(&desc, dreq->inode, FLUSH_STABLE, false,
&nfs_direct_write_completion_ops);
desc.pg_dreq = dreq;
req = nfs_list_entry(reqs.next);
nfs_direct_setup_mirroring(dreq, &desc, req);
list_for_each_entry_safe(req, tmp, &reqs, wb_list) {
if (!nfs_pageio_add_request(&desc, req)) {
nfs_list_remove_request(req);
@ -730,12 +775,7 @@ static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
dreq->error = hdr->error;
}
if (dreq->error == 0) {
/*
* FIXME: right now this only accounts for bytes written
* to the first mirror
*/
if (hdr->pgio_mirror_idx == 0)
dreq->count += hdr->good_bytes;
nfs_direct_good_bytes(dreq, hdr);
if (nfs_write_need_commit(hdr)) {
if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES)
request_commit = true;
@ -841,6 +881,9 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
result = PTR_ERR(req);
break;
}
nfs_direct_setup_mirroring(dreq, &desc, req);
nfs_lock_request(req);
req->wb_index = pos >> PAGE_SHIFT;
req->wb_offset = pos & ~PAGE_MASK;