From 0a00b77b331a0e4aac461d4e920677661256918a Mon Sep 17 00:00:00 2001 From: Weston Andros Adamson Date: Fri, 19 Sep 2014 12:48:33 -0400 Subject: [PATCH] nfs: mirroring support for direct io 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 --- fs/nfs/direct.c | 71 +++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 57 insertions(+), 14 deletions(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 0178d4fe8ab7..651387bbfd9f 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -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; -- 2.20.1