NFS: merge _full and _partial read rpc_ops
[cascardo/linux.git] / fs / nfs / read.c
index f6ab30b..c9633b2 100644 (file)
 #define NFSDBG_FACILITY                NFSDBG_PAGECACHE
 
 static const struct nfs_pageio_ops nfs_pageio_read_ops;
-static const struct rpc_call_ops nfs_read_partial_ops;
-static const struct rpc_call_ops nfs_read_full_ops;
+static const struct rpc_call_ops nfs_read_common_ops;
 
 static struct kmem_cache *nfs_rdata_cachep;
 
-struct nfs_read_header *nfs_readhdr_alloc(unsigned int pagecount)
+struct nfs_read_header *nfs_readhdr_alloc()
 {
-       struct nfs_read_header *p;
+       struct nfs_read_header *rhdr;
 
-       p = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
-       if (p) {
-               struct nfs_pgio_header *hdr = &p->header;
-               struct nfs_read_data *data = &p->rpc_data;
+       rhdr = kmem_cache_zalloc(nfs_rdata_cachep, GFP_KERNEL);
+       if (rhdr) {
+               struct nfs_pgio_header *hdr = &rhdr->header;
 
                INIT_LIST_HEAD(&hdr->pages);
-               INIT_LIST_HEAD(&data->list);
+               INIT_LIST_HEAD(&hdr->rpc_list);
+               spin_lock_init(&hdr->lock);
+               atomic_set(&hdr->refcnt, 0);
+       }
+       return rhdr;
+}
+
+struct nfs_read_data *nfs_readdata_alloc(struct nfs_pgio_header *hdr,
+                                        unsigned int pagecount)
+{
+       struct nfs_read_data *data, *prealloc;
+
+       prealloc = &container_of(hdr, struct nfs_read_header, header)->rpc_data;
+       if (prealloc->header == NULL)
+               data = prealloc;
+       else
+               data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               goto out;
+
+       if (nfs_pgarray_set(&data->pages, pagecount)) {
                data->header = hdr;
-               if (!nfs_pgarray_set(&data->pages, pagecount)) {
-                       kmem_cache_free(nfs_rdata_cachep, p);
-                       p = NULL;
-               }
+               atomic_inc(&hdr->refcnt);
+       } else {
+               if (data != prealloc)
+                       kfree(data);
+               data = NULL;
        }
-       return p;
+out:
+       return data;
 }
 
 void nfs_readhdr_free(struct nfs_pgio_header *hdr)
@@ -64,10 +84,18 @@ void nfs_readhdr_free(struct nfs_pgio_header *hdr)
 
 void nfs_readdata_release(struct nfs_read_data *rdata)
 {
+       struct nfs_pgio_header *hdr = rdata->header;
+       struct nfs_read_header *read_header = container_of(hdr, struct nfs_read_header, header);
+
        put_nfs_open_context(rdata->args.context);
        if (rdata->pages.pagevec != rdata->pages.page_array)
                kfree(rdata->pages.pagevec);
-       nfs_readhdr_free(rdata->header);
+       if (rdata != &read_header->rpc_data)
+               kfree(rdata);
+       else
+               rdata->header = NULL;
+       if (atomic_dec_and_test(&hdr->refcnt))
+               nfs_read_completion(hdr);
 }
 
 static
@@ -79,35 +107,6 @@ int nfs_return_empty_page(struct page *page)
        return 0;
 }
 
-static void nfs_readpage_truncate_uninitialised_page(struct nfs_read_data *data)
-{
-       unsigned int remainder = data->args.count - data->res.count;
-       unsigned int base = data->args.pgbase + data->res.count;
-       unsigned int pglen;
-       struct page **pages;
-
-       if (data->res.eof == 0 || remainder == 0)
-               return;
-       /*
-        * Note: "remainder" can never be negative, since we check for
-        *      this in the XDR code.
-        */
-       pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
-       base &= ~PAGE_CACHE_MASK;
-       pglen = PAGE_CACHE_SIZE - base;
-       for (;;) {
-               if (remainder <= pglen) {
-                       zero_user(*pages, base, remainder);
-                       break;
-               }
-               zero_user(*pages, base, pglen);
-               pages++;
-               remainder -= pglen;
-               pglen = PAGE_CACHE_SIZE;
-               base = 0;
-       }
-}
-
 void nfs_pageio_init_read_mds(struct nfs_pageio_descriptor *pgio,
                struct inode *inode)
 {
@@ -170,6 +169,46 @@ static void nfs_readpage_release(struct nfs_page *req)
        nfs_release_request(req);
 }
 
+/* Note io was page aligned */
+void nfs_read_completion(struct nfs_pgio_header *hdr)
+{
+       unsigned long bytes = 0;
+
+       if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
+               goto out;
+       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);
+                       }
+                       SetPageUptodate(page);
+                       nfs_list_remove_request(req);
+                       nfs_readpage_release(req);
+                       bytes += PAGE_SIZE;
+               }
+       } else {
+               while (!list_empty(&hdr->pages)) {
+                       struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+
+                       bytes += req->wb_bytes;
+                       if (bytes <= hdr->good_bytes)
+                               SetPageUptodate(req->wb_page);
+                       nfs_list_remove_request(req);
+                       nfs_readpage_release(req);
+               }
+       }
+out:
+       hdr->release(hdr);
+}
+
 int nfs_initiate_read(struct rpc_clnt *clnt,
                      struct nfs_read_data *data,
                      const struct rpc_call_ops *call_ops)
@@ -214,16 +253,12 @@ EXPORT_SYMBOL_GPL(nfs_initiate_read);
 /*
  * Set up the NFS read request struct
  */
-static void nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
+static void nfs_read_rpcsetup(struct nfs_read_data *data,
                unsigned int count, unsigned int offset)
 {
-       struct inode *inode = data->header->inode;
-
-       data->header->req         = req;
-       data->header->inode       = inode;
-       data->header->cred        = req->wb_context->cred;
+       struct nfs_page *req = data->header->req;
 
-       data->args.fh     = NFS_FH(inode);
+       data->args.fh     = NFS_FH(data->header->inode);
        data->args.offset = req_offset(req) + offset;
        data->args.pgbase = req->wb_pgbase + offset;
        data->args.pages  = data->pages.pagevec;
@@ -255,7 +290,7 @@ nfs_do_multiple_reads(struct list_head *head,
        while (!list_empty(head)) {
                int ret2;
 
-               data = list_entry(head->next, struct nfs_read_data, list);
+               data = list_first_entry(head, struct nfs_read_data, list);
                list_del_init(&data->list);
 
                ret2 = nfs_do_read(data, call_ops);
@@ -265,7 +300,7 @@ nfs_do_multiple_reads(struct list_head *head,
        return ret;
 }
 
-static void
+void
 nfs_async_read_error(struct list_head *head)
 {
        struct nfs_page *req;
@@ -290,11 +325,11 @@ nfs_async_read_error(struct list_head *head)
  * won't see the new data until our attribute cache is updated.  This is more
  * or less conventional NFS client behavior.
  */
-static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc, struct list_head *res)
+static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc,
+                           struct nfs_pgio_header *hdr)
 {
-       struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
+       struct nfs_page *req = hdr->req;
        struct page *page = req->wb_page;
-       struct nfs_read_header *rhdr;
        struct nfs_read_data *data;
        size_t rsize = desc->pg_bsize, nbytes;
        unsigned int offset;
@@ -302,85 +337,97 @@ static int nfs_pagein_multi(struct nfs_pageio_descriptor *desc, struct list_head
        int ret = 0;
 
        nfs_list_remove_request(req);
+       nfs_list_add_request(req, &hdr->pages);
 
        offset = 0;
        nbytes = desc->pg_count;
        do {
                size_t len = min(nbytes,rsize);
 
-               rhdr = nfs_readhdr_alloc(1);
-               if (!rhdr)
+               data = nfs_readdata_alloc(hdr, 1);
+               if (!data)
                        goto out_bad;
-               data = &rhdr->rpc_data;
                data->pages.pagevec[0] = page;
-               nfs_read_rpcsetup(req, data, len, offset);
-               list_add(&data->list, res);
+               nfs_read_rpcsetup(data, len, offset);
+               list_add(&data->list, &hdr->rpc_list);
                requests++;
                nbytes -= len;
                offset += len;
        } while(nbytes != 0);
-       atomic_set(&req->wb_complete, requests);
-       desc->pg_rpc_callops = &nfs_read_partial_ops;
+       desc->pg_rpc_callops = &nfs_read_common_ops;
        return ret;
 out_bad:
-       while (!list_empty(res)) {
-               data = list_entry(res->next, struct nfs_read_data, list);
+       while (!list_empty(&hdr->rpc_list)) {
+               data = list_first_entry(&hdr->rpc_list, struct nfs_read_data, list);
                list_del(&data->list);
                nfs_readdata_release(data);
        }
-       nfs_readpage_release(req);
+       nfs_async_read_error(&hdr->pages);
        return -ENOMEM;
 }
 
-static int nfs_pagein_one(struct nfs_pageio_descriptor *desc, struct list_head *res)
+static int nfs_pagein_one(struct nfs_pageio_descriptor *desc,
+                         struct nfs_pgio_header *hdr)
 {
        struct nfs_page         *req;
        struct page             **pages;
-       struct nfs_read_header  *rhdr;
-       struct nfs_read_data    *data;
+       struct nfs_read_data    *data;
        struct list_head *head = &desc->pg_list;
        int ret = 0;
 
-       rhdr = nfs_readhdr_alloc(nfs_page_array_len(desc->pg_base,
-                                                   desc->pg_count));
-       if (!rhdr) {
+       data = nfs_readdata_alloc(hdr, nfs_page_array_len(desc->pg_base,
+                                                         desc->pg_count));
+       if (!data) {
                nfs_async_read_error(head);
                ret = -ENOMEM;
                goto out;
        }
 
-       data = &rhdr->rpc_data;
        pages = data->pages.pagevec;
        while (!list_empty(head)) {
                req = nfs_list_entry(head->next);
                nfs_list_remove_request(req);
-               nfs_list_add_request(req, &rhdr->header.pages);
+               nfs_list_add_request(req, &hdr->pages);
                *pages++ = req->wb_page;
        }
-       req = nfs_list_entry(rhdr->header.pages.next);
 
-       nfs_read_rpcsetup(req, data, desc->pg_count, 0);
-       list_add(&data->list, res);
-       desc->pg_rpc_callops = &nfs_read_full_ops;
+       nfs_read_rpcsetup(data, desc->pg_count, 0);
+       list_add(&data->list, &hdr->rpc_list);
+       desc->pg_rpc_callops = &nfs_read_common_ops;
 out:
        return ret;
 }
 
-int nfs_generic_pagein(struct nfs_pageio_descriptor *desc, struct list_head *head)
+int nfs_generic_pagein(struct nfs_pageio_descriptor *desc,
+                      struct nfs_pgio_header *hdr)
 {
        if (desc->pg_bsize < PAGE_CACHE_SIZE)
-               return nfs_pagein_multi(desc, head);
-       return nfs_pagein_one(desc, head);
+               return nfs_pagein_multi(desc, hdr);
+       return nfs_pagein_one(desc, hdr);
 }
 
 static int nfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
 {
-       LIST_HEAD(head);
+       struct nfs_read_header *rhdr;
+       struct nfs_pgio_header *hdr;
        int ret;
 
-       ret = nfs_generic_pagein(desc, &head);
+       rhdr = nfs_readhdr_alloc();
+       if (!rhdr) {
+               nfs_async_read_error(&desc->pg_list);
+               return -ENOMEM;
+       }
+       hdr = &rhdr->header;
+       nfs_pgheader_init(desc, hdr, nfs_readhdr_free);
+       atomic_inc(&hdr->refcnt);
+       ret = nfs_generic_pagein(desc, hdr);
        if (ret == 0)
-               ret = nfs_do_multiple_reads(&head, desc->pg_rpc_callops);
+               ret = nfs_do_multiple_reads(&hdr->rpc_list,
+                                           desc->pg_rpc_callops);
+       else
+               set_bit(NFS_IOHDR_REDO, &hdr->flags);
+       if (atomic_dec_and_test(&hdr->refcnt))
+               nfs_read_completion(hdr);
        return ret;
 }
 
@@ -419,15 +466,13 @@ static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data
        struct nfs_readargs *argp = &data->args;
        struct nfs_readres *resp = &data->res;
 
-       if (resp->eof || resp->count == argp->count)
-               return;
-
        /* This is a short read! */
        nfs_inc_stats(data->header->inode, NFSIOS_SHORTREAD);
        /* Has the server at least made some progress? */
-       if (resp->count == 0)
+       if (resp->count == 0) {
+               nfs_set_pgio_error(data->header, -EIO, argp->offset);
                return;
-
+       }
        /* Yes, so retry the read at the end of the data */
        data->mds_offset += resp->count;
        argp->offset += resp->count;
@@ -436,38 +481,34 @@ static void nfs_readpage_retry(struct rpc_task *task, struct nfs_read_data *data
        rpc_restart_call_prepare(task);
 }
 
-/*
- * Handle a read reply that fills part of a page.
- */
-static void nfs_readpage_result_partial(struct rpc_task *task, void *calldata)
+static void nfs_readpage_result_common(struct rpc_task *task, void *calldata)
 {
        struct nfs_read_data *data = calldata;
+       struct nfs_pgio_header *hdr = data->header;
+
+       /* Note the only returns of nfs_readpage_result are 0 and -EAGAIN */
        if (nfs_readpage_result(task, data) != 0)
                return;
        if (task->tk_status < 0)
-               return;
-
-       nfs_readpage_truncate_uninitialised_page(data);
-       nfs_readpage_retry(task, data);
+               nfs_set_pgio_error(hdr, task->tk_status, data->args.offset);
+       else if (data->res.eof) {
+               loff_t bound;
+
+               bound = data->args.offset + data->res.count;
+               spin_lock(&hdr->lock);
+               if (bound < hdr->io_start + hdr->good_bytes) {
+                       set_bit(NFS_IOHDR_EOF, &hdr->flags);
+                       clear_bit(NFS_IOHDR_ERROR, &hdr->flags);
+                       hdr->good_bytes = bound - hdr->io_start;
+               }
+               spin_unlock(&hdr->lock);
+       } else if (data->res.count != data->args.count)
+               nfs_readpage_retry(task, data);
 }
 
-static void nfs_readpage_release_partial(void *calldata)
+static void nfs_readpage_release_common(void *calldata)
 {
-       struct nfs_read_data *data = calldata;
-       struct nfs_page *req = data->header->req;
-       struct page *page = req->wb_page;
-       int status = data->task.tk_status;
-
-       if (status < 0)
-               set_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags);
-
-       if (atomic_dec_and_test(&req->wb_complete)) {
-               if (!test_bit(PG_PARTIAL_READ_FAILED, &req->wb_flags))
-                       SetPageUptodate(page);
-               nfs_readpage_release(req);
-       }
-       nfs_readdata_release(data);
+       nfs_readdata_release(calldata);
 }
 
 void nfs_read_prepare(struct rpc_task *task, void *calldata)
@@ -476,75 +517,10 @@ void nfs_read_prepare(struct rpc_task *task, void *calldata)
        NFS_PROTO(data->header->inode)->read_rpc_prepare(task, data);
 }
 
-static const struct rpc_call_ops nfs_read_partial_ops = {
-       .rpc_call_prepare = nfs_read_prepare,
-       .rpc_call_done = nfs_readpage_result_partial,
-       .rpc_release = nfs_readpage_release_partial,
-};
-
-static void nfs_readpage_set_pages_uptodate(struct nfs_read_data *data)
-{
-       unsigned int count = data->res.count;
-       unsigned int base = data->args.pgbase;
-       struct page **pages;
-
-       if (data->res.eof)
-               count = data->args.count;
-       if (unlikely(count == 0))
-               return;
-       pages = &data->args.pages[base >> PAGE_CACHE_SHIFT];
-       base &= ~PAGE_CACHE_MASK;
-       count += base;
-       for (;count >= PAGE_CACHE_SIZE; count -= PAGE_CACHE_SIZE, pages++)
-               SetPageUptodate(*pages);
-       if (count == 0)
-               return;
-       /* Was this a short read? */
-       if (data->res.eof || data->res.count == data->args.count)
-               SetPageUptodate(*pages);
-}
-
-/*
- * This is the callback from RPC telling us whether a reply was
- * received or some error occurred (timeout or socket shutdown).
- */
-static void nfs_readpage_result_full(struct rpc_task *task, void *calldata)
-{
-       struct nfs_read_data *data = calldata;
-
-       if (nfs_readpage_result(task, data) != 0)
-               return;
-       if (task->tk_status < 0)
-               return;
-       /*
-        * Note: nfs_readpage_retry may change the values of
-        * data->args. In the multi-page case, we therefore need
-        * to ensure that we call nfs_readpage_set_pages_uptodate()
-        * first.
-        */
-       nfs_readpage_truncate_uninitialised_page(data);
-       nfs_readpage_set_pages_uptodate(data);
-       nfs_readpage_retry(task, data);
-}
-
-static void nfs_readpage_release_full(void *calldata)
-{
-       struct nfs_read_data *data = calldata;
-       struct nfs_pgio_header *hdr = data->header;
-
-       while (!list_empty(&hdr->pages)) {
-               struct nfs_page *req = nfs_list_entry(hdr->pages.next);
-
-               nfs_list_remove_request(req);
-               nfs_readpage_release(req);
-       }
-       nfs_readdata_release(calldata);
-}
-
-static const struct rpc_call_ops nfs_read_full_ops = {
+static const struct rpc_call_ops nfs_read_common_ops = {
        .rpc_call_prepare = nfs_read_prepare,
-       .rpc_call_done = nfs_readpage_result_full,
-       .rpc_release = nfs_readpage_release_full,
+       .rpc_call_done = nfs_readpage_result_common,
+       .rpc_release = nfs_readpage_release_common,
 };
 
 /*