NFS: rewrite directio read to use async coalesce code

This also has the advantage that it allows directio to use pnfs.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 123 insertions, 132 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 22a40c408449..4ba9a2c839bb 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -124,22 +124,6 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_
         return -EINVAL;
 }
 
-static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count)
-{
-        unsigned int npages;
-        unsigned int i;
-
-        if (count == 0)
-                return;
-        pages += (pgbase >> PAGE_SHIFT);
-        npages = (count + (pgbase & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
-        for (i = 0; i < npages; i++) {
-                struct page *page = pages[i];
-                if (!PageCompound(page))
-                        set_page_dirty(page);
-        }
-}
-
 static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
 {
         unsigned int i;
@@ -226,58 +210,92 @@ static void nfs_direct_complete(struct nfs_direct_req *dreq)
         nfs_direct_req_release(dreq);
 }
 
-/*
- * We must hold a reference to all the pages in this direct read request
- * until the RPCs complete.  This could be long *after* we are woken up in
- * nfs_direct_wait (for instance, if someone hits ^C on a slow server).
- */
-static void nfs_direct_read_result(struct rpc_task *task, void *calldata)
+void nfs_direct_readpage_release(struct nfs_page *req)
 {
-        struct nfs_read_data *data = calldata;
-
-        nfs_readpage_result(task, data);
+        dprintk("NFS: direct read done (%s/%lld %d@%lld)\n",
+                req->wb_context->dentry->d_inode->i_sb->s_id,
+                (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
+                req->wb_bytes,
+                (long long)req_offset(req));
+        nfs_release_request(req);
 }
 
-static void nfs_direct_read_release(void *calldata)
+static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
 {
+        unsigned long bytes = 0;
+        struct nfs_direct_req *dreq = hdr->dreq;
 
-        struct nfs_read_data *data = calldata;
-        struct nfs_direct_req *dreq = (struct nfs_direct_req *)data->header->req;
-        int status = data->task.tk_status;
+        if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
+                goto out_put;
 
         spin_lock(&dreq->lock);
-        if (unlikely(status < 0)) {
-                dreq->error = status;
-                spin_unlock(&dreq->lock);
+        if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0))
+                dreq->error = hdr->error;
+        else
+                dreq->count += hdr->good_bytes;
+        spin_unlock(&dreq->lock);
+
+        if (!test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
+                while (!list_empty(&hdr->pages)) {
+                        struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+                        struct page *page = req->wb_page;
+
+                        if (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
+                                if (bytes > hdr->good_bytes)
+                                        zero_user(page, 0, PAGE_SIZE);
+                                else if (hdr->good_bytes - bytes < PAGE_SIZE)
+                                        zero_user_segment(page,
+                                                hdr->good_bytes & ~PAGE_MASK,
+                                                PAGE_SIZE);
+                        }
+                        bytes += req->wb_bytes;
+                        nfs_list_remove_request(req);
+                        nfs_direct_readpage_release(req);
+                        if (!PageCompound(page))
+                                set_page_dirty(page);
+                        page_cache_release(page);
+                }
         } else {
-                dreq->count += data->res.count;
-                spin_unlock(&dreq->lock);
-                nfs_direct_dirty_pages(data->pages.pagevec,
-                                data->args.pgbase,
-                                data->res.count);
+                while (!list_empty(&hdr->pages)) {
+                        struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+
+                        if (bytes < hdr->good_bytes)
+                                if (!PageCompound(req->wb_page))
+                                        set_page_dirty(req->wb_page);
+                        bytes += req->wb_bytes;
+                        page_cache_release(req->wb_page);
+                        nfs_list_remove_request(req);
+                        nfs_direct_readpage_release(req);
+                }
         }
-        nfs_direct_release_pages(data->pages.pagevec, data->pages.npages);
-
+out_put:
         if (put_dreq(dreq))
                 nfs_direct_complete(dreq);
-        nfs_readdata_release(data);
+        hdr->release(hdr);
 }
 
-static const struct rpc_call_ops nfs_read_direct_ops = {
-        .rpc_call_prepare = nfs_read_prepare,
-        .rpc_call_done = nfs_direct_read_result,
-        .rpc_release = nfs_direct_read_release,
-};
-
-static void nfs_direct_readhdr_release(struct nfs_read_header *rhdr)
+static void nfs_sync_pgio_error(struct list_head *head)
 {
-        struct nfs_read_data *data = &rhdr->rpc_data;
+        struct nfs_page *req;
 
-        if (data->pages.pagevec != data->pages.page_array)
-                kfree(data->pages.pagevec);
-        nfs_readhdr_free(&rhdr->header);
+        while (!list_empty(head)) {
+                req = nfs_list_entry(head->next);
+                nfs_list_remove_request(req);
+                nfs_release_request(req);
+        }
 }
 
+static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr)
+{
+        get_dreq(hdr->dreq);
+}
+
+static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = {
+        .error_cleanup = nfs_sync_pgio_error,
+        .init_hdr = nfs_direct_pgio_init,
+        .completion = nfs_direct_read_completion,
+};
+
 /*
  * For each rsize'd chunk of the user's buffer, dispatch an NFS READ
  * operation.  If nfs_readdata_alloc() or get_user_pages() fails,
@@ -285,118 +303,85 @@ static void nfs_direct_readhdr_release(struct nfs_read_header *rhdr)
  * handled automatically by nfs_direct_read_result().  Otherwise, if
  * no requests have been sent, just return an error.
  */
-static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
+static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc,
                                                 const struct iovec *iov,
                                                 loff_t pos)
 {
+        struct nfs_direct_req *dreq = desc->pg_dreq;
         struct nfs_open_context *ctx = dreq->ctx;
         struct inode *inode = ctx->dentry->d_inode;
         unsigned long user_addr = (unsigned long)iov->iov_base;
         size_t count = iov->iov_len;
         size_t rsize = NFS_SERVER(inode)->rsize;
-        struct rpc_task *task;
-        struct rpc_message msg = {
-                .rpc_cred = ctx->cred,
-        };
-        struct rpc_task_setup task_setup_data = {
-                .rpc_client = NFS_CLIENT(inode),
-                .rpc_message = &msg,
-                .callback_ops = &nfs_read_direct_ops,
-                .workqueue = nfsiod_workqueue,
-                .flags = RPC_TASK_ASYNC,
-        };
         unsigned int pgbase;
         int result;
         ssize_t started = 0;
+        struct page **pagevec = NULL;
+        unsigned int npages;
 
         do {
-                struct nfs_read_header *rhdr;
-                struct nfs_read_data *data;
-                struct nfs_page_array *pages;
                 size_t bytes;
+                int i;
 
                 pgbase = user_addr & ~PAGE_MASK;
-                bytes = min(rsize,count);
+                bytes = min(max(rsize, PAGE_SIZE), count);
 
                 result = -ENOMEM;
-                rhdr = nfs_readhdr_alloc();
-                if (unlikely(!rhdr))
-                        break;
-                data = nfs_readdata_alloc(&rhdr->header, nfs_page_array_len(pgbase, bytes));
-                if (!data) {
-                        nfs_readhdr_free(&rhdr->header);
+                npages = nfs_page_array_len(pgbase, bytes);
+                if (!pagevec)
+                        pagevec = kmalloc(npages * sizeof(struct page *),
+                                          GFP_KERNEL);
+                if (!pagevec)
                         break;
-                }
-                data->header = &rhdr->header;
-                atomic_inc(&data->header->refcnt);
-                pages = &data->pages;
-
                 down_read(&current->mm->mmap_sem);
                 result = get_user_pages(current, current->mm, user_addr,
-                                        pages->npages, 1, 0, pages->pagevec, NULL);
+                                        npages, 1, 0, pagevec, NULL);
                 up_read(&current->mm->mmap_sem);
-                if (result < 0) {
-                        nfs_direct_readhdr_release(rhdr);
+                if (result < 0)
                         break;
-                }
-                if ((unsigned)result < pages->npages) {
+                if ((unsigned)result < npages) {
                         bytes = result * PAGE_SIZE;
                         if (bytes <= pgbase) {
-                                nfs_direct_release_pages(pages->pagevec, result);
-                                nfs_direct_readhdr_release(rhdr);
+                                nfs_direct_release_pages(pagevec, result);
                                 break;
                         }
                         bytes -= pgbase;
-                        pages->npages = result;
+                        npages = result;
                 }
 
-                get_dreq(dreq);
-
-                rhdr->header.req = (struct nfs_page *) dreq;
-                rhdr->header.inode = inode;
-                rhdr->header.cred = msg.rpc_cred;
-                data->args.fh = NFS_FH(inode);
-                data->args.context = get_nfs_open_context(ctx);
-                data->args.lock_context = dreq->l_ctx;
-                data->args.offset = pos;
-                data->args.pgbase = pgbase;
-                data->args.pages = pages->pagevec;
-                data->args.count = bytes;
-                data->res.fattr = &data->fattr;
-                data->res.eof = 0;
-                data->res.count = bytes;
-                nfs_fattr_init(&data->fattr);
-                msg.rpc_argp = &data->args;
-                msg.rpc_resp = &data->res;
-
-                task_setup_data.task = &data->task;
-                task_setup_data.callback_data = data;
-                NFS_PROTO(inode)->read_setup(data, &msg);
-
-                task = rpc_run_task(&task_setup_data);
-                if (IS_ERR(task))
-                        break;
-
-                dprintk("NFS: %5u initiated direct read call "
-                        "(req %s/%Ld, %zu bytes @ offset %Lu)\n",
-                                task->tk_pid,
-                                inode->i_sb->s_id,
-                                (long long)NFS_FILEID(inode),
-                                bytes,
-                                (unsigned long long)data->args.offset);
-                rpc_put_task(task);
-
-                started += bytes;
-                user_addr += bytes;
-                pos += bytes;
-                /* FIXME: Remove this unnecessary math from final patch */
-                pgbase += bytes;
-                pgbase &= ~PAGE_MASK;
-                BUG_ON(pgbase != (user_addr & ~PAGE_MASK));
-
-                count -= bytes;
+                for (i = 0; i < npages; i++) {
+                        struct nfs_page *req;
+                        unsigned int req_len = min(bytes, PAGE_SIZE - pgbase);
+                        /* XXX do we need to do the eof zeroing found in async_filler? */
+                        req = nfs_create_request(dreq->ctx, dreq->inode,
+                                                 pagevec[i],
+                                                 pgbase, req_len);
+                        if (IS_ERR(req)) {
+                                nfs_direct_release_pages(pagevec + i,
+                                                         npages - i);
+                                result = PTR_ERR(req);
+                                break;
+                        }
+                        req->wb_index = pos >> PAGE_SHIFT;
+                        req->wb_offset = pos & ~PAGE_MASK;
+                        if (!nfs_pageio_add_request(desc, req)) {
+                                result = desc->pg_error;
+                                nfs_release_request(req);
+                                nfs_direct_release_pages(pagevec + i,
+                                                         npages - i);
+                                break;
+                        }
+                        pgbase = 0;
+                        bytes -= req_len;
+                        started += req_len;
+                        user_addr += req_len;
+                        pos += req_len;
+                        count -= req_len;
+                }
         } while (count != 0);
 
+        kfree(pagevec);
+
         if (started)
                 return started;
         return result < 0 ? (ssize_t) result : -EFAULT;
@@ -407,15 +392,19 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
                                               unsigned long nr_segs,
                                               loff_t pos)
 {
+        struct nfs_pageio_descriptor desc;
         ssize_t result = -EINVAL;
         size_t requested_bytes = 0;
         unsigned long seg;
 
+        nfs_pageio_init_read(&desc, dreq->inode,
+                             &nfs_direct_read_completion_ops);
         get_dreq(dreq);
+        desc.pg_dreq = dreq;
 
         for (seg = 0; seg < nr_segs; seg++) {
                 const struct iovec *vec = &iov[seg];
-                result = nfs_direct_read_schedule_segment(dreq, vec, pos);
+                result = nfs_direct_read_schedule_segment(&desc, vec, pos);
                 if (result < 0)
                         break;
                 requested_bytes += result;
@@ -424,6 +413,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
                 pos += vec->iov_len;
         }
 
+        nfs_pageio_complete(&desc);
+
         /*
          * If no bytes were started, return the error, and let the
          * generic layer handle the completion.