v4.19.13 snapshot.
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
new file mode 100644
index 0000000..586726a
--- /dev/null
+++ b/fs/nfs/write.c
@@ -0,0 +1,2153 @@
+/*
+ * linux/fs/nfs/write.c
+ *
+ * Write file data over NFS.
+ *
+ * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/writeback.h>
+#include <linux/swap.h>
+#include <linux/migrate.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/nfs_page.h>
+#include <linux/backing-dev.h>
+#include <linux/export.h>
+#include <linux/freezer.h>
+#include <linux/wait.h>
+#include <linux/iversion.h>
+
+#include <linux/uaccess.h>
+
+#include "delegation.h"
+#include "internal.h"
+#include "iostat.h"
+#include "nfs4_fs.h"
+#include "fscache.h"
+#include "pnfs.h"
+
+#include "nfstrace.h"
+
+#define NFSDBG_FACILITY NFSDBG_PAGECACHE
+
+#define MIN_POOL_WRITE (32)
+#define MIN_POOL_COMMIT (4)
+
+struct nfs_io_completion {
+ void (*complete)(void *data);
+ void *data;
+ struct kref refcount;
+};
+
+/*
+ * Local function declarations
+ */
+static void nfs_redirty_request(struct nfs_page *req);
+static const struct rpc_call_ops nfs_commit_ops;
+static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
+static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
+static const struct nfs_rw_ops nfs_rw_write_ops;
+static void nfs_clear_request_commit(struct nfs_page *req);
+static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
+ struct inode *inode);
+static struct nfs_page *
+nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
+ struct page *page);
+
+static struct kmem_cache *nfs_wdata_cachep;
+static mempool_t *nfs_wdata_mempool;
+static struct kmem_cache *nfs_cdata_cachep;
+static mempool_t *nfs_commit_mempool;
+
+struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail)
+{
+ struct nfs_commit_data *p;
+
+ if (never_fail)
+ p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
+ else {
+ /* It is OK to do some reclaim, not no safe to wait
+ * for anything to be returned to the pool.
+ * mempool_alloc() cannot handle that particular combination,
+ * so we need two separate attempts.
+ */
+ p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
+ if (!p)
+ p = kmem_cache_alloc(nfs_cdata_cachep, GFP_NOIO |
+ __GFP_NOWARN | __GFP_NORETRY);
+ if (!p)
+ return NULL;
+ }
+
+ memset(p, 0, sizeof(*p));
+ INIT_LIST_HEAD(&p->pages);
+ return p;
+}
+EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
+
+void nfs_commit_free(struct nfs_commit_data *p)
+{
+ mempool_free(p, nfs_commit_mempool);
+}
+EXPORT_SYMBOL_GPL(nfs_commit_free);
+
+static struct nfs_pgio_header *nfs_writehdr_alloc(void)
+{
+ struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
+
+ memset(p, 0, sizeof(*p));
+ p->rw_mode = FMODE_WRITE;
+ return p;
+}
+
+static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
+{
+ mempool_free(hdr, nfs_wdata_mempool);
+}
+
+static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
+{
+ return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
+}
+
+static void nfs_io_completion_init(struct nfs_io_completion *ioc,
+ void (*complete)(void *), void *data)
+{
+ ioc->complete = complete;
+ ioc->data = data;
+ kref_init(&ioc->refcount);
+}
+
+static void nfs_io_completion_release(struct kref *kref)
+{
+ struct nfs_io_completion *ioc = container_of(kref,
+ struct nfs_io_completion, refcount);
+ ioc->complete(ioc->data);
+ kfree(ioc);
+}
+
+static void nfs_io_completion_get(struct nfs_io_completion *ioc)
+{
+ if (ioc != NULL)
+ kref_get(&ioc->refcount);
+}
+
+static void nfs_io_completion_put(struct nfs_io_completion *ioc)
+{
+ if (ioc != NULL)
+ kref_put(&ioc->refcount, nfs_io_completion_release);
+}
+
+static struct nfs_page *
+nfs_page_private_request(struct page *page)
+{
+ if (!PagePrivate(page))
+ return NULL;
+ return (struct nfs_page *)page_private(page);
+}
+
+/*
+ * nfs_page_find_head_request_locked - find head request associated with @page
+ *
+ * must be called while holding the inode lock.
+ *
+ * returns matching head request with reference held, or NULL if not found.
+ */
+static struct nfs_page *
+nfs_page_find_private_request(struct page *page)
+{
+ struct address_space *mapping = page_file_mapping(page);
+ struct nfs_page *req;
+
+ if (!PagePrivate(page))
+ return NULL;
+ spin_lock(&mapping->private_lock);
+ req = nfs_page_private_request(page);
+ if (req) {
+ WARN_ON_ONCE(req->wb_head != req);
+ kref_get(&req->wb_kref);
+ }
+ spin_unlock(&mapping->private_lock);
+ return req;
+}
+
+static struct nfs_page *
+nfs_page_find_swap_request(struct page *page)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs_page *req = NULL;
+ if (!PageSwapCache(page))
+ return NULL;
+ mutex_lock(&nfsi->commit_mutex);
+ if (PageSwapCache(page)) {
+ req = nfs_page_search_commits_for_head_request_locked(nfsi,
+ page);
+ if (req) {
+ WARN_ON_ONCE(req->wb_head != req);
+ kref_get(&req->wb_kref);
+ }
+ }
+ mutex_unlock(&nfsi->commit_mutex);
+ return req;
+}
+
+/*
+ * nfs_page_find_head_request - find head request associated with @page
+ *
+ * returns matching head request with reference held, or NULL if not found.
+ */
+static struct nfs_page *nfs_page_find_head_request(struct page *page)
+{
+ struct nfs_page *req;
+
+ req = nfs_page_find_private_request(page);
+ if (!req)
+ req = nfs_page_find_swap_request(page);
+ return req;
+}
+
+/* Adjust the file length if we're writing beyond the end */
+static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ loff_t end, i_size;
+ pgoff_t end_index;
+
+ spin_lock(&inode->i_lock);
+ i_size = i_size_read(inode);
+ end_index = (i_size - 1) >> PAGE_SHIFT;
+ if (i_size > 0 && page_index(page) < end_index)
+ goto out;
+ end = page_file_offset(page) + ((loff_t)offset+count);
+ if (i_size >= end)
+ goto out;
+ i_size_write(inode, end);
+ NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
+ nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
+out:
+ spin_unlock(&inode->i_lock);
+}
+
+/* A writeback failed: mark the page as bad, and invalidate the page cache */
+static void nfs_set_pageerror(struct page *page)
+{
+ nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
+}
+
+/*
+ * nfs_page_group_search_locked
+ * @head - head request of page group
+ * @page_offset - offset into page
+ *
+ * Search page group with head @head to find a request that contains the
+ * page offset @page_offset.
+ *
+ * Returns a pointer to the first matching nfs request, or NULL if no
+ * match is found.
+ *
+ * Must be called with the page group lock held
+ */
+static struct nfs_page *
+nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
+{
+ struct nfs_page *req;
+
+ req = head;
+ do {
+ if (page_offset >= req->wb_pgbase &&
+ page_offset < (req->wb_pgbase + req->wb_bytes))
+ return req;
+
+ req = req->wb_this_page;
+ } while (req != head);
+
+ return NULL;
+}
+
+/*
+ * nfs_page_group_covers_page
+ * @head - head request of page group
+ *
+ * Return true if the page group with head @head covers the whole page,
+ * returns false otherwise
+ */
+static bool nfs_page_group_covers_page(struct nfs_page *req)
+{
+ struct nfs_page *tmp;
+ unsigned int pos = 0;
+ unsigned int len = nfs_page_length(req->wb_page);
+
+ nfs_page_group_lock(req);
+
+ for (;;) {
+ tmp = nfs_page_group_search_locked(req->wb_head, pos);
+ if (!tmp)
+ break;
+ pos = tmp->wb_pgbase + tmp->wb_bytes;
+ }
+
+ nfs_page_group_unlock(req);
+ return pos >= len;
+}
+
+/* We can set the PG_uptodate flag if we see that a write request
+ * covers the full page.
+ */
+static void nfs_mark_uptodate(struct nfs_page *req)
+{
+ if (PageUptodate(req->wb_page))
+ return;
+ if (!nfs_page_group_covers_page(req))
+ return;
+ SetPageUptodate(req->wb_page);
+}
+
+static int wb_priority(struct writeback_control *wbc)
+{
+ int ret = 0;
+
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ ret = FLUSH_COND_STABLE;
+ return ret;
+}
+
+/*
+ * NFS congestion control
+ */
+
+int nfs_congestion_kb;
+
+#define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10))
+#define NFS_CONGESTION_OFF_THRESH \
+ (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
+
+static void nfs_set_page_writeback(struct page *page)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_server *nfss = NFS_SERVER(inode);
+ int ret = test_set_page_writeback(page);
+
+ WARN_ON_ONCE(ret != 0);
+
+ if (atomic_long_inc_return(&nfss->writeback) >
+ NFS_CONGESTION_ON_THRESH)
+ set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
+}
+
+static void nfs_end_page_writeback(struct nfs_page *req)
+{
+ struct inode *inode = page_file_mapping(req->wb_page)->host;
+ struct nfs_server *nfss = NFS_SERVER(inode);
+ bool is_done;
+
+ is_done = nfs_page_group_sync_on_bit(req, PG_WB_END);
+ nfs_unlock_request(req);
+ if (!is_done)
+ return;
+
+ end_page_writeback(req->wb_page);
+ if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
+ clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
+}
+
+/*
+ * nfs_unroll_locks_and_wait - unlock all newly locked reqs and wait on @req
+ *
+ * this is a helper function for nfs_lock_and_join_requests
+ *
+ * @inode - inode associated with request page group, must be holding inode lock
+ * @head - head request of page group, must be holding head lock
+ * @req - request that couldn't lock and needs to wait on the req bit lock
+ *
+ * NOTE: this must be called holding page_group bit lock
+ * which will be released before returning.
+ *
+ * returns 0 on success, < 0 on error.
+ */
+static void
+nfs_unroll_locks(struct inode *inode, struct nfs_page *head,
+ struct nfs_page *req)
+{
+ struct nfs_page *tmp;
+
+ /* relinquish all the locks successfully grabbed this run */
+ for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
+ if (!kref_read(&tmp->wb_kref))
+ continue;
+ nfs_unlock_and_release_request(tmp);
+ }
+}
+
+/*
+ * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
+ *
+ * @destroy_list - request list (using wb_this_page) terminated by @old_head
+ * @old_head - the old head of the list
+ *
+ * All subrequests must be locked and removed from all lists, so at this point
+ * they are only "active" in this function, and possibly in nfs_wait_on_request
+ * with a reference held by some other context.
+ */
+static void
+nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
+ struct nfs_page *old_head,
+ struct inode *inode)
+{
+ while (destroy_list) {
+ struct nfs_page *subreq = destroy_list;
+
+ destroy_list = (subreq->wb_this_page == old_head) ?
+ NULL : subreq->wb_this_page;
+
+ WARN_ON_ONCE(old_head != subreq->wb_head);
+
+ /* make sure old group is not used */
+ subreq->wb_this_page = subreq;
+
+ clear_bit(PG_REMOVE, &subreq->wb_flags);
+
+ /* Note: races with nfs_page_group_destroy() */
+ if (!kref_read(&subreq->wb_kref)) {
+ /* Check if we raced with nfs_page_group_destroy() */
+ if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags))
+ nfs_free_request(subreq);
+ continue;
+ }
+
+ subreq->wb_head = subreq;
+
+ if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
+ nfs_release_request(subreq);
+ atomic_long_dec(&NFS_I(inode)->nrequests);
+ }
+
+ /* subreq is now totally disconnected from page group or any
+ * write / commit lists. last chance to wake any waiters */
+ nfs_unlock_and_release_request(subreq);
+ }
+}
+
+/*
+ * nfs_lock_and_join_requests - join all subreqs to the head req and return
+ * a locked reference, cancelling any pending
+ * operations for this page.
+ *
+ * @page - the page used to lookup the "page group" of nfs_page structures
+ *
+ * This function joins all sub requests to the head request by first
+ * locking all requests in the group, cancelling any pending operations
+ * and finally updating the head request to cover the whole range covered by
+ * the (former) group. All subrequests are removed from any write or commit
+ * lists, unlinked from the group and destroyed.
+ *
+ * Returns a locked, referenced pointer to the head request - which after
+ * this call is guaranteed to be the only request associated with the page.
+ * Returns NULL if no requests are found for @page, or a ERR_PTR if an
+ * error was encountered.
+ */
+static struct nfs_page *
+nfs_lock_and_join_requests(struct page *page)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_page *head, *subreq;
+ struct nfs_page *destroy_list = NULL;
+ unsigned int total_bytes;
+ int ret;
+
+try_again:
+ /*
+ * A reference is taken only on the head request which acts as a
+ * reference to the whole page group - the group will not be destroyed
+ * until the head reference is released.
+ */
+ head = nfs_page_find_head_request(page);
+ if (!head)
+ return NULL;
+
+ /* lock the page head first in order to avoid an ABBA inefficiency */
+ if (!nfs_lock_request(head)) {
+ ret = nfs_wait_on_request(head);
+ nfs_release_request(head);
+ if (ret < 0)
+ return ERR_PTR(ret);
+ goto try_again;
+ }
+
+ /* Ensure that nobody removed the request before we locked it */
+ if (head != nfs_page_private_request(page) && !PageSwapCache(page)) {
+ nfs_unlock_and_release_request(head);
+ goto try_again;
+ }
+
+ ret = nfs_page_group_lock(head);
+ if (ret < 0)
+ goto release_request;
+
+ /* lock each request in the page group */
+ total_bytes = head->wb_bytes;
+ for (subreq = head->wb_this_page; subreq != head;
+ subreq = subreq->wb_this_page) {
+
+ if (!kref_get_unless_zero(&subreq->wb_kref)) {
+ if (subreq->wb_offset == head->wb_offset + total_bytes)
+ total_bytes += subreq->wb_bytes;
+ continue;
+ }
+
+ while (!nfs_lock_request(subreq)) {
+ /*
+ * Unlock page to allow nfs_page_group_sync_on_bit()
+ * to succeed
+ */
+ nfs_page_group_unlock(head);
+ ret = nfs_wait_on_request(subreq);
+ if (!ret)
+ ret = nfs_page_group_lock(head);
+ if (ret < 0) {
+ nfs_unroll_locks(inode, head, subreq);
+ nfs_release_request(subreq);
+ goto release_request;
+ }
+ }
+ /*
+ * Subrequests are always contiguous, non overlapping
+ * and in order - but may be repeated (mirrored writes).
+ */
+ if (subreq->wb_offset == (head->wb_offset + total_bytes)) {
+ /* keep track of how many bytes this group covers */
+ total_bytes += subreq->wb_bytes;
+ } else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset ||
+ ((subreq->wb_offset + subreq->wb_bytes) >
+ (head->wb_offset + total_bytes)))) {
+ nfs_page_group_unlock(head);
+ nfs_unroll_locks(inode, head, subreq);
+ nfs_unlock_and_release_request(subreq);
+ ret = -EIO;
+ goto release_request;
+ }
+ }
+
+ /* Now that all requests are locked, make sure they aren't on any list.
+ * Commit list removal accounting is done after locks are dropped */
+ subreq = head;
+ do {
+ nfs_clear_request_commit(subreq);
+ subreq = subreq->wb_this_page;
+ } while (subreq != head);
+
+ /* unlink subrequests from head, destroy them later */
+ if (head->wb_this_page != head) {
+ /* destroy list will be terminated by head */
+ destroy_list = head->wb_this_page;
+ head->wb_this_page = head;
+
+ /* change head request to cover whole range that
+ * the former page group covered */
+ head->wb_bytes = total_bytes;
+ }
+
+ /* Postpone destruction of this request */
+ if (test_and_clear_bit(PG_REMOVE, &head->wb_flags)) {
+ set_bit(PG_INODE_REF, &head->wb_flags);
+ kref_get(&head->wb_kref);
+ atomic_long_inc(&NFS_I(inode)->nrequests);
+ }
+
+ nfs_page_group_unlock(head);
+
+ nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
+
+ /* Did we lose a race with nfs_inode_remove_request()? */
+ if (!(PagePrivate(page) || PageSwapCache(page))) {
+ nfs_unlock_and_release_request(head);
+ return NULL;
+ }
+
+ /* still holds ref on head from nfs_page_find_head_request
+ * and still has lock on head from lock loop */
+ return head;
+
+release_request:
+ nfs_unlock_and_release_request(head);
+ return ERR_PTR(ret);
+}
+
+static void nfs_write_error_remove_page(struct nfs_page *req)
+{
+ nfs_end_page_writeback(req);
+ generic_error_remove_page(page_file_mapping(req->wb_page),
+ req->wb_page);
+ nfs_release_request(req);
+}
+
+static bool
+nfs_error_is_fatal_on_server(int err)
+{
+ switch (err) {
+ case 0:
+ case -ERESTARTSYS:
+ case -EINTR:
+ return false;
+ }
+ return nfs_error_is_fatal(err);
+}
+
+/*
+ * Find an associated nfs write request, and prepare to flush it out
+ * May return an error if the user signalled nfs_wait_on_request().
+ */
+static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
+ struct page *page)
+{
+ struct nfs_page *req;
+ int ret = 0;
+
+ req = nfs_lock_and_join_requests(page);
+ if (!req)
+ goto out;
+ ret = PTR_ERR(req);
+ if (IS_ERR(req))
+ goto out;
+
+ nfs_set_page_writeback(page);
+ WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
+
+ ret = 0;
+ /* If there is a fatal error that covers this write, just exit */
+ if (nfs_error_is_fatal_on_server(req->wb_context->error))
+ goto out_launder;
+
+ if (!nfs_pageio_add_request(pgio, req)) {
+ ret = pgio->pg_error;
+ /*
+ * Remove the problematic req upon fatal errors on the server
+ */
+ if (nfs_error_is_fatal(ret)) {
+ nfs_context_set_write_error(req->wb_context, ret);
+ if (nfs_error_is_fatal_on_server(ret))
+ goto out_launder;
+ }
+ nfs_redirty_request(req);
+ ret = -EAGAIN;
+ } else
+ nfs_add_stats(page_file_mapping(page)->host,
+ NFSIOS_WRITEPAGES, 1);
+out:
+ return ret;
+out_launder:
+ nfs_write_error_remove_page(req);
+ return ret;
+}
+
+static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
+ struct nfs_pageio_descriptor *pgio)
+{
+ int ret;
+
+ nfs_pageio_cond_complete(pgio, page_index(page));
+ ret = nfs_page_async_flush(pgio, page);
+ if (ret == -EAGAIN) {
+ redirty_page_for_writepage(wbc, page);
+ ret = 0;
+ }
+ return ret;
+}
+
+/*
+ * Write an mmapped page to the server.
+ */
+static int nfs_writepage_locked(struct page *page,
+ struct writeback_control *wbc)
+{
+ struct nfs_pageio_descriptor pgio;
+ struct inode *inode = page_file_mapping(page)->host;
+ int err;
+
+ nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
+ nfs_pageio_init_write(&pgio, inode, 0,
+ false, &nfs_async_write_completion_ops);
+ err = nfs_do_writepage(page, wbc, &pgio);
+ nfs_pageio_complete(&pgio);
+ if (err < 0)
+ return err;
+ if (pgio.pg_error < 0)
+ return pgio.pg_error;
+ return 0;
+}
+
+int nfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+ int ret;
+
+ ret = nfs_writepage_locked(page, wbc);
+ unlock_page(page);
+ return ret;
+}
+
+static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
+{
+ int ret;
+
+ ret = nfs_do_writepage(page, wbc, data);
+ unlock_page(page);
+ return ret;
+}
+
+static void nfs_io_completion_commit(void *inode)
+{
+ nfs_commit_inode(inode, 0);
+}
+
+int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+ struct inode *inode = mapping->host;
+ struct nfs_pageio_descriptor pgio;
+ struct nfs_io_completion *ioc = nfs_io_completion_alloc(GFP_NOFS);
+ int err;
+
+ nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
+
+ if (ioc)
+ nfs_io_completion_init(ioc, nfs_io_completion_commit, inode);
+
+ nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
+ &nfs_async_write_completion_ops);
+ pgio.pg_io_completion = ioc;
+ err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
+ nfs_pageio_complete(&pgio);
+ nfs_io_completion_put(ioc);
+
+ if (err < 0)
+ goto out_err;
+ err = pgio.pg_error;
+ if (err < 0)
+ goto out_err;
+ return 0;
+out_err:
+ return err;
+}
+
+/*
+ * Insert a write request into an inode
+ */
+static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
+{
+ struct address_space *mapping = page_file_mapping(req->wb_page);
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ WARN_ON_ONCE(req->wb_this_page != req);
+
+ /* Lock the request! */
+ nfs_lock_request(req);
+
+ /*
+ * Swap-space should not get truncated. Hence no need to plug the race
+ * with invalidate/truncate.
+ */
+ spin_lock(&mapping->private_lock);
+ if (!nfs_have_writebacks(inode) &&
+ NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
+ inode_inc_iversion_raw(inode);
+ if (likely(!PageSwapCache(req->wb_page))) {
+ set_bit(PG_MAPPED, &req->wb_flags);
+ SetPagePrivate(req->wb_page);
+ set_page_private(req->wb_page, (unsigned long)req);
+ }
+ spin_unlock(&mapping->private_lock);
+ atomic_long_inc(&nfsi->nrequests);
+ /* this a head request for a page group - mark it as having an
+ * extra reference so sub groups can follow suit.
+ * This flag also informs pgio layer when to bump nrequests when
+ * adding subrequests. */
+ WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
+ kref_get(&req->wb_kref);
+}
+
+/*
+ * Remove a write request from an inode
+ */
+static void nfs_inode_remove_request(struct nfs_page *req)
+{
+ struct address_space *mapping = page_file_mapping(req->wb_page);
+ struct inode *inode = mapping->host;
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs_page *head;
+
+ atomic_long_dec(&nfsi->nrequests);
+ if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
+ head = req->wb_head;
+
+ spin_lock(&mapping->private_lock);
+ if (likely(head->wb_page && !PageSwapCache(head->wb_page))) {
+ set_page_private(head->wb_page, 0);
+ ClearPagePrivate(head->wb_page);
+ clear_bit(PG_MAPPED, &head->wb_flags);
+ }
+ spin_unlock(&mapping->private_lock);
+ }
+
+ if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags))
+ nfs_release_request(req);
+}
+
+static void
+nfs_mark_request_dirty(struct nfs_page *req)
+{
+ if (req->wb_page)
+ __set_page_dirty_nobuffers(req->wb_page);
+}
+
+/*
+ * nfs_page_search_commits_for_head_request_locked
+ *
+ * Search through commit lists on @inode for the head request for @page.
+ * Must be called while holding the inode (which is cinfo) lock.
+ *
+ * Returns the head request if found, or NULL if not found.
+ */
+static struct nfs_page *
+nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
+ struct page *page)
+{
+ struct nfs_page *freq, *t;
+ struct nfs_commit_info cinfo;
+ struct inode *inode = &nfsi->vfs_inode;
+
+ nfs_init_cinfo_from_inode(&cinfo, inode);
+
+ /* search through pnfs commit lists */
+ freq = pnfs_search_commit_reqs(inode, &cinfo, page);
+ if (freq)
+ return freq->wb_head;
+
+ /* Linearly search the commit list for the correct request */
+ list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
+ if (freq->wb_page == page)
+ return freq->wb_head;
+ }
+
+ return NULL;
+}
+
+/**
+ * nfs_request_add_commit_list_locked - add request to a commit list
+ * @req: pointer to a struct nfs_page
+ * @dst: commit list head
+ * @cinfo: holds list lock and accounting info
+ *
+ * This sets the PG_CLEAN bit, updates the cinfo count of
+ * number of outstanding requests requiring a commit as well as
+ * the MM page stats.
+ *
+ * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
+ * nfs_page lock.
+ */
+void
+nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
+ struct nfs_commit_info *cinfo)
+{
+ set_bit(PG_CLEAN, &req->wb_flags);
+ nfs_list_add_request(req, dst);
+ atomic_long_inc(&cinfo->mds->ncommit);
+}
+EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
+
+/**
+ * nfs_request_add_commit_list - add request to a commit list
+ * @req: pointer to a struct nfs_page
+ * @dst: commit list head
+ * @cinfo: holds list lock and accounting info
+ *
+ * This sets the PG_CLEAN bit, updates the cinfo count of
+ * number of outstanding requests requiring a commit as well as
+ * the MM page stats.
+ *
+ * The caller must _not_ hold the cinfo->lock, but must be
+ * holding the nfs_page lock.
+ */
+void
+nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
+{
+ mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+ nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
+ mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+ if (req->wb_page)
+ nfs_mark_page_unstable(req->wb_page, cinfo);
+}
+EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
+
+/**
+ * nfs_request_remove_commit_list - Remove request from a commit list
+ * @req: pointer to a nfs_page
+ * @cinfo: holds list lock and accounting info
+ *
+ * This clears the PG_CLEAN bit, and updates the cinfo's count of
+ * number of outstanding requests requiring a commit
+ * It does not update the MM page stats.
+ *
+ * The caller _must_ hold the cinfo->lock and the nfs_page lock.
+ */
+void
+nfs_request_remove_commit_list(struct nfs_page *req,
+ struct nfs_commit_info *cinfo)
+{
+ if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
+ return;
+ nfs_list_remove_request(req);
+ atomic_long_dec(&cinfo->mds->ncommit);
+}
+EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
+
+static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
+ struct inode *inode)
+{
+ cinfo->inode = inode;
+ cinfo->mds = &NFS_I(inode)->commit_info;
+ cinfo->ds = pnfs_get_ds_info(inode);
+ cinfo->dreq = NULL;
+ cinfo->completion_ops = &nfs_commit_completion_ops;
+}
+
+void nfs_init_cinfo(struct nfs_commit_info *cinfo,
+ struct inode *inode,
+ struct nfs_direct_req *dreq)
+{
+ if (dreq)
+ nfs_init_cinfo_from_dreq(cinfo, dreq);
+ else
+ nfs_init_cinfo_from_inode(cinfo, inode);
+}
+EXPORT_SYMBOL_GPL(nfs_init_cinfo);
+
+/*
+ * Add a request to the inode's commit list.
+ */
+void
+nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
+ struct nfs_commit_info *cinfo, u32 ds_commit_idx)
+{
+ if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
+ return;
+ nfs_request_add_commit_list(req, cinfo);
+}
+
+static void
+nfs_clear_page_commit(struct page *page)
+{
+ dec_node_page_state(page, NR_UNSTABLE_NFS);
+ dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
+ WB_RECLAIMABLE);
+}
+
+/* Called holding the request lock on @req */
+static void
+nfs_clear_request_commit(struct nfs_page *req)
+{
+ if (test_bit(PG_CLEAN, &req->wb_flags)) {
+ struct inode *inode = d_inode(req->wb_context->dentry);
+ struct nfs_commit_info cinfo;
+
+ nfs_init_cinfo_from_inode(&cinfo, inode);
+ mutex_lock(&NFS_I(inode)->commit_mutex);
+ if (!pnfs_clear_request_commit(req, &cinfo)) {
+ nfs_request_remove_commit_list(req, &cinfo);
+ }
+ mutex_unlock(&NFS_I(inode)->commit_mutex);
+ nfs_clear_page_commit(req->wb_page);
+ }
+}
+
+int nfs_write_need_commit(struct nfs_pgio_header *hdr)
+{
+ if (hdr->verf.committed == NFS_DATA_SYNC)
+ return hdr->lseg == NULL;
+ return hdr->verf.committed != NFS_FILE_SYNC;
+}
+
+static void nfs_async_write_init(struct nfs_pgio_header *hdr)
+{
+ nfs_io_completion_get(hdr->io_completion);
+}
+
+static void nfs_write_completion(struct nfs_pgio_header *hdr)
+{
+ struct nfs_commit_info cinfo;
+ unsigned long bytes = 0;
+
+ if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
+ goto out;
+ nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
+ while (!list_empty(&hdr->pages)) {
+ struct nfs_page *req = nfs_list_entry(hdr->pages.next);
+
+ bytes += req->wb_bytes;
+ nfs_list_remove_request(req);
+ if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
+ (hdr->good_bytes < bytes)) {
+ nfs_set_pageerror(req->wb_page);
+ nfs_context_set_write_error(req->wb_context, hdr->error);
+ goto remove_req;
+ }
+ if (nfs_write_need_commit(hdr)) {
+ memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
+ nfs_mark_request_commit(req, hdr->lseg, &cinfo,
+ hdr->pgio_mirror_idx);
+ goto next;
+ }
+remove_req:
+ nfs_inode_remove_request(req);
+next:
+ nfs_end_page_writeback(req);
+ nfs_release_request(req);
+ }
+out:
+ nfs_io_completion_put(hdr->io_completion);
+ hdr->release(hdr);
+}
+
+unsigned long
+nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
+{
+ return atomic_long_read(&cinfo->mds->ncommit);
+}
+
+/* NFS_I(cinfo->inode)->commit_mutex held by caller */
+int
+nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
+ struct nfs_commit_info *cinfo, int max)
+{
+ struct nfs_page *req, *tmp;
+ int ret = 0;
+
+restart:
+ list_for_each_entry_safe(req, tmp, src, wb_list) {
+ kref_get(&req->wb_kref);
+ if (!nfs_lock_request(req)) {
+ int status;
+
+ /* Prevent deadlock with nfs_lock_and_join_requests */
+ if (!list_empty(dst)) {
+ nfs_release_request(req);
+ continue;
+ }
+ /* Ensure we make progress to prevent livelock */
+ mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+ status = nfs_wait_on_request(req);
+ nfs_release_request(req);
+ mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+ if (status < 0)
+ break;
+ goto restart;
+ }
+ nfs_request_remove_commit_list(req, cinfo);
+ clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
+ nfs_list_add_request(req, dst);
+ ret++;
+ if ((ret == max) && !cinfo->dreq)
+ break;
+ cond_resched();
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
+
+/*
+ * nfs_scan_commit - Scan an inode for commit requests
+ * @inode: NFS inode to scan
+ * @dst: mds destination list
+ * @cinfo: mds and ds lists of reqs ready to commit
+ *
+ * Moves requests from the inode's 'commit' request list.
+ * The requests are *not* checked to ensure that they form a contiguous set.
+ */
+int
+nfs_scan_commit(struct inode *inode, struct list_head *dst,
+ struct nfs_commit_info *cinfo)
+{
+ int ret = 0;
+
+ if (!atomic_long_read(&cinfo->mds->ncommit))
+ return 0;
+ mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
+ if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
+ const int max = INT_MAX;
+
+ ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
+ cinfo, max);
+ ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
+ }
+ mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
+ return ret;
+}
+
+/*
+ * Search for an existing write request, and attempt to update
+ * it to reflect a new dirty region on a given page.
+ *
+ * If the attempt fails, then the existing request is flushed out
+ * to disk.
+ */
+static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
+ struct page *page,
+ unsigned int offset,
+ unsigned int bytes)
+{
+ struct nfs_page *req;
+ unsigned int rqend;
+ unsigned int end;
+ int error;
+
+ end = offset + bytes;
+
+ req = nfs_lock_and_join_requests(page);
+ if (IS_ERR_OR_NULL(req))
+ return req;
+
+ rqend = req->wb_offset + req->wb_bytes;
+ /*
+ * Tell the caller to flush out the request if
+ * the offsets are non-contiguous.
+ * Note: nfs_flush_incompatible() will already
+ * have flushed out requests having wrong owners.
+ */
+ if (offset > rqend || end < req->wb_offset)
+ goto out_flushme;
+
+ /* Okay, the request matches. Update the region */
+ if (offset < req->wb_offset) {
+ req->wb_offset = offset;
+ req->wb_pgbase = offset;
+ }
+ if (end > rqend)
+ req->wb_bytes = end - req->wb_offset;
+ else
+ req->wb_bytes = rqend - req->wb_offset;
+ return req;
+out_flushme:
+ /*
+ * Note: we mark the request dirty here because
+ * nfs_lock_and_join_requests() cannot preserve
+ * commit flags, so we have to replay the write.
+ */
+ nfs_mark_request_dirty(req);
+ nfs_unlock_and_release_request(req);
+ error = nfs_wb_page(inode, page);
+ return (error < 0) ? ERR_PTR(error) : NULL;
+}
+
+/*
+ * Try to update an existing write request, or create one if there is none.
+ *
+ * Note: Should always be called with the Page Lock held to prevent races
+ * if we have to add a new request. Also assumes that the caller has
+ * already called nfs_flush_incompatible() if necessary.
+ */
+static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
+ struct page *page, unsigned int offset, unsigned int bytes)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_page *req;
+
+ req = nfs_try_to_update_request(inode, page, offset, bytes);
+ if (req != NULL)
+ goto out;
+ req = nfs_create_request(ctx, page, NULL, offset, bytes);
+ if (IS_ERR(req))
+ goto out;
+ nfs_inode_add_request(inode, req);
+out:
+ return req;
+}
+
+static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
+ unsigned int offset, unsigned int count)
+{
+ struct nfs_page *req;
+
+ req = nfs_setup_write_request(ctx, page, offset, count);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+ /* Update file length */
+ nfs_grow_file(page, offset, count);
+ nfs_mark_uptodate(req);
+ nfs_mark_request_dirty(req);
+ nfs_unlock_and_release_request(req);
+ return 0;
+}
+
+int nfs_flush_incompatible(struct file *file, struct page *page)
+{
+ struct nfs_open_context *ctx = nfs_file_open_context(file);
+ struct nfs_lock_context *l_ctx;
+ struct file_lock_context *flctx = file_inode(file)->i_flctx;
+ struct nfs_page *req;
+ int do_flush, status;
+ /*
+ * Look for a request corresponding to this page. If there
+ * is one, and it belongs to another file, we flush it out
+ * before we try to copy anything into the page. Do this
+ * due to the lack of an ACCESS-type call in NFSv2.
+ * Also do the same if we find a request from an existing
+ * dropped page.
+ */
+ do {
+ req = nfs_page_find_head_request(page);
+ if (req == NULL)
+ return 0;
+ l_ctx = req->wb_lock_context;
+ do_flush = req->wb_page != page ||
+ !nfs_match_open_context(req->wb_context, ctx);
+ if (l_ctx && flctx &&
+ !(list_empty_careful(&flctx->flc_posix) &&
+ list_empty_careful(&flctx->flc_flock))) {
+ do_flush |= l_ctx->lockowner != current->files;
+ }
+ nfs_release_request(req);
+ if (!do_flush)
+ return 0;
+ status = nfs_wb_page(page_file_mapping(page)->host, page);
+ } while (status == 0);
+ return status;
+}
+
+/*
+ * Avoid buffered writes when a open context credential's key would
+ * expire soon.
+ *
+ * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
+ *
+ * Return 0 and set a credential flag which triggers the inode to flush
+ * and performs NFS_FILE_SYNC writes if the key will expired within
+ * RPC_KEY_EXPIRE_TIMEO.
+ */
+int
+nfs_key_timeout_notify(struct file *filp, struct inode *inode)
+{
+ struct nfs_open_context *ctx = nfs_file_open_context(filp);
+ struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
+
+ return rpcauth_key_timeout_notify(auth, ctx->cred);
+}
+
+/*
+ * Test if the open context credential key is marked to expire soon.
+ */
+bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
+{
+ struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
+
+ return rpcauth_cred_key_to_expire(auth, ctx->cred);
+}
+
+/*
+ * If the page cache is marked as unsafe or invalid, then we can't rely on
+ * the PageUptodate() flag. In this case, we will need to turn off
+ * write optimisations that depend on the page contents being correct.
+ */
+static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (nfs_have_delegated_attributes(inode))
+ goto out;
+ if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
+ return false;
+ smp_rmb();
+ if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
+ return false;
+out:
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+ return false;
+ return PageUptodate(page) != 0;
+}
+
+static bool
+is_whole_file_wrlock(struct file_lock *fl)
+{
+ return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
+ fl->fl_type == F_WRLCK;
+}
+
+/* If we know the page is up to date, and we're not using byte range locks (or
+ * if we have the whole file locked for writing), it may be more efficient to
+ * extend the write to cover the entire page in order to avoid fragmentation
+ * inefficiencies.
+ *
+ * If the file is opened for synchronous writes then we can just skip the rest
+ * of the checks.
+ */
+static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
+{
+ int ret;
+ struct file_lock_context *flctx = inode->i_flctx;
+ struct file_lock *fl;
+
+ if (file->f_flags & O_DSYNC)
+ return 0;
+ if (!nfs_write_pageuptodate(page, inode))
+ return 0;
+ if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
+ return 1;
+ if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
+ list_empty_careful(&flctx->flc_posix)))
+ return 1;
+
+ /* Check to see if there are whole file write locks */
+ ret = 0;
+ spin_lock(&flctx->flc_lock);
+ if (!list_empty(&flctx->flc_posix)) {
+ fl = list_first_entry(&flctx->flc_posix, struct file_lock,
+ fl_list);
+ if (is_whole_file_wrlock(fl))
+ ret = 1;
+ } else if (!list_empty(&flctx->flc_flock)) {
+ fl = list_first_entry(&flctx->flc_flock, struct file_lock,
+ fl_list);
+ if (fl->fl_type == F_WRLCK)
+ ret = 1;
+ }
+ spin_unlock(&flctx->flc_lock);
+ return ret;
+}
+
+/*
+ * Update and possibly write a cached page of an NFS file.
+ *
+ * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
+ * things with a page scheduled for an RPC call (e.g. invalidate it).
+ */
+int nfs_updatepage(struct file *file, struct page *page,
+ unsigned int offset, unsigned int count)
+{
+ struct nfs_open_context *ctx = nfs_file_open_context(file);
+ struct inode *inode = page_file_mapping(page)->host;
+ int status = 0;
+
+ nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
+
+ dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n",
+ file, count, (long long)(page_file_offset(page) + offset));
+
+ if (!count)
+ goto out;
+
+ if (nfs_can_extend_write(file, page, inode)) {
+ count = max(count + offset, nfs_page_length(page));
+ offset = 0;
+ }
+
+ status = nfs_writepage_setup(ctx, page, offset, count);
+ if (status < 0)
+ nfs_set_pageerror(page);
+ else
+ __set_page_dirty_nobuffers(page);
+out:
+ dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
+ status, (long long)i_size_read(inode));
+ return status;
+}
+
+static int flush_task_priority(int how)
+{
+ switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
+ case FLUSH_HIGHPRI:
+ return RPC_PRIORITY_HIGH;
+ case FLUSH_LOWPRI:
+ return RPC_PRIORITY_LOW;
+ }
+ return RPC_PRIORITY_NORMAL;
+}
+
+static void nfs_initiate_write(struct nfs_pgio_header *hdr,
+ struct rpc_message *msg,
+ const struct nfs_rpc_ops *rpc_ops,
+ struct rpc_task_setup *task_setup_data, int how)
+{
+ int priority = flush_task_priority(how);
+
+ task_setup_data->priority = priority;
+ rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
+ trace_nfs_initiate_write(hdr->inode, hdr->io_start, hdr->good_bytes,
+ hdr->args.stable);
+}
+
+/* If a nfs_flush_* function fails, it should remove reqs from @head and
+ * call this on each, which will prepare them to be retried on next
+ * writeback using standard nfs.
+ */
+static void nfs_redirty_request(struct nfs_page *req)
+{
+ nfs_mark_request_dirty(req);
+ set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
+ nfs_end_page_writeback(req);
+ nfs_release_request(req);
+}
+
+static void nfs_async_write_error(struct list_head *head)
+{
+ struct nfs_page *req;
+
+ while (!list_empty(head)) {
+ req = nfs_list_entry(head->next);
+ nfs_list_remove_request(req);
+ nfs_redirty_request(req);
+ }
+}
+
+static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
+{
+ nfs_async_write_error(&hdr->pages);
+ filemap_fdatawrite_range(hdr->inode->i_mapping, hdr->args.offset,
+ hdr->args.offset + hdr->args.count - 1);
+}
+
+static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
+ .init_hdr = nfs_async_write_init,
+ .error_cleanup = nfs_async_write_error,
+ .completion = nfs_write_completion,
+ .reschedule_io = nfs_async_write_reschedule_io,
+};
+
+void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
+ struct inode *inode, int ioflags, bool force_mds,
+ const struct nfs_pgio_completion_ops *compl_ops)
+{
+ struct nfs_server *server = NFS_SERVER(inode);
+ const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
+
+#ifdef CONFIG_NFS_V4_1
+ if (server->pnfs_curr_ld && !force_mds)
+ pg_ops = server->pnfs_curr_ld->pg_write_ops;
+#endif
+ nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
+ server->wsize, ioflags);
+}
+EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
+
+void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
+{
+ struct nfs_pgio_mirror *mirror;
+
+ if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
+ pgio->pg_ops->pg_cleanup(pgio);
+
+ pgio->pg_ops = &nfs_pgio_rw_ops;
+
+ nfs_pageio_stop_mirroring(pgio);
+
+ mirror = &pgio->pg_mirrors[0];
+ mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
+}
+EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
+
+
+void nfs_commit_prepare(struct rpc_task *task, void *calldata)
+{
+ struct nfs_commit_data *data = calldata;
+
+ NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
+}
+
+/*
+ * Special version of should_remove_suid() that ignores capabilities.
+ */
+static int nfs_should_remove_suid(const struct inode *inode)
+{
+ umode_t mode = inode->i_mode;
+ int kill = 0;
+
+ /* suid always must be killed */
+ if (unlikely(mode & S_ISUID))
+ kill = ATTR_KILL_SUID;
+
+ /*
+ * sgid without any exec bits is just a mandatory locking mark; leave
+ * it alone. If some exec bits are set, it's a real sgid; kill it.
+ */
+ if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
+ kill |= ATTR_KILL_SGID;
+
+ if (unlikely(kill && S_ISREG(mode)))
+ return kill;
+
+ return 0;
+}
+
+static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
+ struct nfs_fattr *fattr)
+{
+ struct nfs_pgio_args *argp = &hdr->args;
+ struct nfs_pgio_res *resp = &hdr->res;
+ u64 size = argp->offset + resp->count;
+
+ if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
+ fattr->size = size;
+ if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
+ fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
+ return;
+ }
+ if (size != fattr->size)
+ return;
+ /* Set attribute barrier */
+ nfs_fattr_set_barrier(fattr);
+ /* ...and update size */
+ fattr->valid |= NFS_ATTR_FATTR_SIZE;
+}
+
+void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
+{
+ struct nfs_fattr *fattr = &hdr->fattr;
+ struct inode *inode = hdr->inode;
+
+ spin_lock(&inode->i_lock);
+ nfs_writeback_check_extend(hdr, fattr);
+ nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
+ spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
+
+/*
+ * This function is called when the WRITE call is complete.
+ */
+static int nfs_writeback_done(struct rpc_task *task,
+ struct nfs_pgio_header *hdr,
+ struct inode *inode)
+{
+ int status;
+
+ /*
+ * ->write_done will attempt to use post-op attributes to detect
+ * conflicting writes by other clients. A strict interpretation
+ * of close-to-open would allow us to continue caching even if
+ * another writer had changed the file, but some applications
+ * depend on tighter cache coherency when writing.
+ */
+ status = NFS_PROTO(inode)->write_done(task, hdr);
+ if (status != 0)
+ return status;
+
+ nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
+ trace_nfs_writeback_done(inode, task->tk_status,
+ hdr->args.offset, hdr->res.verf);
+
+ if (hdr->res.verf->committed < hdr->args.stable &&
+ task->tk_status >= 0) {
+ /* We tried a write call, but the server did not
+ * commit data to stable storage even though we
+ * requested it.
+ * Note: There is a known bug in Tru64 < 5.0 in which
+ * the server reports NFS_DATA_SYNC, but performs
+ * NFS_FILE_SYNC. We therefore implement this checking
+ * as a dprintk() in order to avoid filling syslog.
+ */
+ static unsigned long complain;
+
+ /* Note this will print the MDS for a DS write */
+ if (time_before(complain, jiffies)) {
+ dprintk("NFS: faulty NFS server %s:"
+ " (committed = %d) != (stable = %d)\n",
+ NFS_SERVER(inode)->nfs_client->cl_hostname,
+ hdr->res.verf->committed, hdr->args.stable);
+ complain = jiffies + 300 * HZ;
+ }
+ }
+
+ /* Deal with the suid/sgid bit corner case */
+ if (nfs_should_remove_suid(inode)) {
+ spin_lock(&inode->i_lock);
+ NFS_I(inode)->cache_validity |= NFS_INO_INVALID_OTHER;
+ spin_unlock(&inode->i_lock);
+ }
+ return 0;
+}
+
+/*
+ * This function is called when the WRITE call is complete.
+ */
+static void nfs_writeback_result(struct rpc_task *task,
+ struct nfs_pgio_header *hdr)
+{
+ struct nfs_pgio_args *argp = &hdr->args;
+ struct nfs_pgio_res *resp = &hdr->res;
+
+ if (resp->count < argp->count) {
+ static unsigned long complain;
+
+ /* This a short write! */
+ nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
+
+ /* Has the server at least made some progress? */
+ if (resp->count == 0) {
+ if (time_before(complain, jiffies)) {
+ printk(KERN_WARNING
+ "NFS: Server wrote zero bytes, expected %u.\n",
+ argp->count);
+ complain = jiffies + 300 * HZ;
+ }
+ nfs_set_pgio_error(hdr, -EIO, argp->offset);
+ task->tk_status = -EIO;
+ return;
+ }
+
+ /* For non rpc-based layout drivers, retry-through-MDS */
+ if (!task->tk_ops) {
+ hdr->pnfs_error = -EAGAIN;
+ return;
+ }
+
+ /* Was this an NFSv2 write or an NFSv3 stable write? */
+ if (resp->verf->committed != NFS_UNSTABLE) {
+ /* Resend from where the server left off */
+ hdr->mds_offset += resp->count;
+ argp->offset += resp->count;
+ argp->pgbase += resp->count;
+ argp->count -= resp->count;
+ } else {
+ /* Resend as a stable write in order to avoid
+ * headaches in the case of a server crash.
+ */
+ argp->stable = NFS_FILE_SYNC;
+ }
+ rpc_restart_call_prepare(task);
+ }
+}
+
+static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
+{
+ return wait_var_event_killable(&cinfo->rpcs_out,
+ !atomic_read(&cinfo->rpcs_out));
+}
+
+static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
+{
+ atomic_inc(&cinfo->rpcs_out);
+}
+
+static void nfs_commit_end(struct nfs_mds_commit_info *cinfo)
+{
+ if (atomic_dec_and_test(&cinfo->rpcs_out))
+ wake_up_var(&cinfo->rpcs_out);
+}
+
+void nfs_commitdata_release(struct nfs_commit_data *data)
+{
+ put_nfs_open_context(data->context);
+ nfs_commit_free(data);
+}
+EXPORT_SYMBOL_GPL(nfs_commitdata_release);
+
+int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
+ const struct nfs_rpc_ops *nfs_ops,
+ const struct rpc_call_ops *call_ops,
+ int how, int flags)
+{
+ struct rpc_task *task;
+ int priority = flush_task_priority(how);
+ struct rpc_message msg = {
+ .rpc_argp = &data->args,
+ .rpc_resp = &data->res,
+ .rpc_cred = data->cred,
+ };
+ struct rpc_task_setup task_setup_data = {
+ .task = &data->task,
+ .rpc_client = clnt,
+ .rpc_message = &msg,
+ .callback_ops = call_ops,
+ .callback_data = data,
+ .workqueue = nfsiod_workqueue,
+ .flags = RPC_TASK_ASYNC | flags,
+ .priority = priority,
+ };
+ /* Set up the initial task struct. */
+ nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
+ trace_nfs_initiate_commit(data);
+
+ dprintk("NFS: initiated commit call\n");
+
+ task = rpc_run_task(&task_setup_data);
+ if (IS_ERR(task))
+ return PTR_ERR(task);
+ if (how & FLUSH_SYNC)
+ rpc_wait_for_completion_task(task);
+ rpc_put_task(task);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_initiate_commit);
+
+static loff_t nfs_get_lwb(struct list_head *head)
+{
+ loff_t lwb = 0;
+ struct nfs_page *req;
+
+ list_for_each_entry(req, head, wb_list)
+ if (lwb < (req_offset(req) + req->wb_bytes))
+ lwb = req_offset(req) + req->wb_bytes;
+
+ return lwb;
+}
+
+/*
+ * Set up the argument/result storage required for the RPC call.
+ */
+void nfs_init_commit(struct nfs_commit_data *data,
+ struct list_head *head,
+ struct pnfs_layout_segment *lseg,
+ struct nfs_commit_info *cinfo)
+{
+ struct nfs_page *first = nfs_list_entry(head->next);
+ struct inode *inode = d_inode(first->wb_context->dentry);
+
+ /* Set up the RPC argument and reply structs
+ * NB: take care not to mess about with data->commit et al. */
+
+ list_splice_init(head, &data->pages);
+
+ data->inode = inode;
+ data->cred = first->wb_context->cred;
+ data->lseg = lseg; /* reference transferred */
+ /* only set lwb for pnfs commit */
+ if (lseg)
+ data->lwb = nfs_get_lwb(&data->pages);
+ data->mds_ops = &nfs_commit_ops;
+ data->completion_ops = cinfo->completion_ops;
+ data->dreq = cinfo->dreq;
+
+ data->args.fh = NFS_FH(data->inode);
+ /* Note: we always request a commit of the entire inode */
+ data->args.offset = 0;
+ data->args.count = 0;
+ data->context = get_nfs_open_context(first->wb_context);
+ data->res.fattr = &data->fattr;
+ data->res.verf = &data->verf;
+ nfs_fattr_init(&data->fattr);
+}
+EXPORT_SYMBOL_GPL(nfs_init_commit);
+
+void nfs_retry_commit(struct list_head *page_list,
+ struct pnfs_layout_segment *lseg,
+ struct nfs_commit_info *cinfo,
+ u32 ds_commit_idx)
+{
+ struct nfs_page *req;
+
+ while (!list_empty(page_list)) {
+ req = nfs_list_entry(page_list->next);
+ nfs_list_remove_request(req);
+ nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
+ if (!cinfo->dreq)
+ nfs_clear_page_commit(req->wb_page);
+ nfs_unlock_and_release_request(req);
+ }
+}
+EXPORT_SYMBOL_GPL(nfs_retry_commit);
+
+static void
+nfs_commit_resched_write(struct nfs_commit_info *cinfo,
+ struct nfs_page *req)
+{
+ __set_page_dirty_nobuffers(req->wb_page);
+}
+
+/*
+ * Commit dirty pages
+ */
+static int
+nfs_commit_list(struct inode *inode, struct list_head *head, int how,
+ struct nfs_commit_info *cinfo)
+{
+ struct nfs_commit_data *data;
+
+ /* another commit raced with us */
+ if (list_empty(head))
+ return 0;
+
+ data = nfs_commitdata_alloc(true);
+
+ /* Set up the argument struct */
+ nfs_init_commit(data, head, NULL, cinfo);
+ atomic_inc(&cinfo->mds->rpcs_out);
+ return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
+ data->mds_ops, how, 0);
+}
+
+/*
+ * COMMIT call returned
+ */
+static void nfs_commit_done(struct rpc_task *task, void *calldata)
+{
+ struct nfs_commit_data *data = calldata;
+
+ dprintk("NFS: %5u nfs_commit_done (status %d)\n",
+ task->tk_pid, task->tk_status);
+
+ /* Call the NFS version-specific code */
+ NFS_PROTO(data->inode)->commit_done(task, data);
+ trace_nfs_commit_done(data);
+}
+
+static void nfs_commit_release_pages(struct nfs_commit_data *data)
+{
+ struct nfs_page *req;
+ int status = data->task.tk_status;
+ struct nfs_commit_info cinfo;
+ struct nfs_server *nfss;
+
+ while (!list_empty(&data->pages)) {
+ req = nfs_list_entry(data->pages.next);
+ nfs_list_remove_request(req);
+ if (req->wb_page)
+ nfs_clear_page_commit(req->wb_page);
+
+ dprintk("NFS: commit (%s/%llu %d@%lld)",
+ req->wb_context->dentry->d_sb->s_id,
+ (unsigned long long)NFS_FILEID(d_inode(req->wb_context->dentry)),
+ req->wb_bytes,
+ (long long)req_offset(req));
+ if (status < 0) {
+ nfs_context_set_write_error(req->wb_context, status);
+ if (req->wb_page)
+ nfs_inode_remove_request(req);
+ dprintk_cont(", error = %d\n", status);
+ goto next;
+ }
+
+ /* Okay, COMMIT succeeded, apparently. Check the verifier
+ * returned by the server against all stored verfs. */
+ if (!nfs_write_verifier_cmp(&req->wb_verf, &data->verf.verifier)) {
+ /* We have a match */
+ if (req->wb_page)
+ nfs_inode_remove_request(req);
+ dprintk_cont(" OK\n");
+ goto next;
+ }
+ /* We have a mismatch. Write the page again */
+ dprintk_cont(" mismatch\n");
+ nfs_mark_request_dirty(req);
+ set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
+ next:
+ nfs_unlock_and_release_request(req);
+ /* Latency breaker */
+ cond_resched();
+ }
+ nfss = NFS_SERVER(data->inode);
+ if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
+ clear_bdi_congested(inode_to_bdi(data->inode), BLK_RW_ASYNC);
+
+ nfs_init_cinfo(&cinfo, data->inode, data->dreq);
+ nfs_commit_end(cinfo.mds);
+}
+
+static void nfs_commit_release(void *calldata)
+{
+ struct nfs_commit_data *data = calldata;
+
+ data->completion_ops->completion(data);
+ nfs_commitdata_release(calldata);
+}
+
+static const struct rpc_call_ops nfs_commit_ops = {
+ .rpc_call_prepare = nfs_commit_prepare,
+ .rpc_call_done = nfs_commit_done,
+ .rpc_release = nfs_commit_release,
+};
+
+static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
+ .completion = nfs_commit_release_pages,
+ .resched_write = nfs_commit_resched_write,
+};
+
+int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
+ int how, struct nfs_commit_info *cinfo)
+{
+ int status;
+
+ status = pnfs_commit_list(inode, head, how, cinfo);
+ if (status == PNFS_NOT_ATTEMPTED)
+ status = nfs_commit_list(inode, head, how, cinfo);
+ return status;
+}
+
+static int __nfs_commit_inode(struct inode *inode, int how,
+ struct writeback_control *wbc)
+{
+ LIST_HEAD(head);
+ struct nfs_commit_info cinfo;
+ int may_wait = how & FLUSH_SYNC;
+ int ret, nscan;
+
+ nfs_init_cinfo_from_inode(&cinfo, inode);
+ nfs_commit_begin(cinfo.mds);
+ for (;;) {
+ ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
+ if (ret <= 0)
+ break;
+ ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
+ if (ret < 0)
+ break;
+ ret = 0;
+ if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
+ if (nscan < wbc->nr_to_write)
+ wbc->nr_to_write -= nscan;
+ else
+ wbc->nr_to_write = 0;
+ }
+ if (nscan < INT_MAX)
+ break;
+ cond_resched();
+ }
+ nfs_commit_end(cinfo.mds);
+ if (ret || !may_wait)
+ return ret;
+ return wait_on_commit(cinfo.mds);
+}
+
+int nfs_commit_inode(struct inode *inode, int how)
+{
+ return __nfs_commit_inode(inode, how, NULL);
+}
+EXPORT_SYMBOL_GPL(nfs_commit_inode);
+
+int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ int flags = FLUSH_SYNC;
+ int ret = 0;
+
+ if (wbc->sync_mode == WB_SYNC_NONE) {
+ /* no commits means nothing needs to be done */
+ if (!atomic_long_read(&nfsi->commit_info.ncommit))
+ goto check_requests_outstanding;
+
+ /* Don't commit yet if this is a non-blocking flush and there
+ * are a lot of outstanding writes for this mapping.
+ */
+ if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
+ goto out_mark_dirty;
+
+ /* don't wait for the COMMIT response */
+ flags = 0;
+ }
+
+ ret = __nfs_commit_inode(inode, flags, wbc);
+ if (!ret) {
+ if (flags & FLUSH_SYNC)
+ return 0;
+ } else if (atomic_long_read(&nfsi->commit_info.ncommit))
+ goto out_mark_dirty;
+
+check_requests_outstanding:
+ if (!atomic_read(&nfsi->commit_info.rpcs_out))
+ return ret;
+out_mark_dirty:
+ __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_write_inode);
+
+/*
+ * Wrapper for filemap_write_and_wait_range()
+ *
+ * Needed for pNFS in order to ensure data becomes visible to the
+ * client.
+ */
+int nfs_filemap_write_and_wait_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend)
+{
+ int ret;
+
+ ret = filemap_write_and_wait_range(mapping, lstart, lend);
+ if (ret == 0)
+ ret = pnfs_sync_inode(mapping->host, true);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
+
+/*
+ * flush the inode to disk.
+ */
+int nfs_wb_all(struct inode *inode)
+{
+ int ret;
+
+ trace_nfs_writeback_inode_enter(inode);
+
+ ret = filemap_write_and_wait(inode->i_mapping);
+ if (ret)
+ goto out;
+ ret = nfs_commit_inode(inode, FLUSH_SYNC);
+ if (ret < 0)
+ goto out;
+ pnfs_sync_inode(inode, true);
+ ret = 0;
+
+out:
+ trace_nfs_writeback_inode_exit(inode, ret);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_wb_all);
+
+int nfs_wb_page_cancel(struct inode *inode, struct page *page)
+{
+ struct nfs_page *req;
+ int ret = 0;
+
+ wait_on_page_writeback(page);
+
+ /* blocking call to cancel all requests and join to a single (head)
+ * request */
+ req = nfs_lock_and_join_requests(page);
+
+ if (IS_ERR(req)) {
+ ret = PTR_ERR(req);
+ } else if (req) {
+ /* all requests from this page have been cancelled by
+ * nfs_lock_and_join_requests, so just remove the head
+ * request from the inode / page_private pointer and
+ * release it */
+ nfs_inode_remove_request(req);
+ nfs_unlock_and_release_request(req);
+ }
+
+ return ret;
+}
+
+/*
+ * Write back all requests on one page - we do this before reading it.
+ */
+int nfs_wb_page(struct inode *inode, struct page *page)
+{
+ loff_t range_start = page_file_offset(page);
+ loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = 0,
+ .range_start = range_start,
+ .range_end = range_end,
+ };
+ int ret;
+
+ trace_nfs_writeback_page_enter(inode);
+
+ for (;;) {
+ wait_on_page_writeback(page);
+ if (clear_page_dirty_for_io(page)) {
+ ret = nfs_writepage_locked(page, &wbc);
+ if (ret < 0)
+ goto out_error;
+ continue;
+ }
+ ret = 0;
+ if (!PagePrivate(page))
+ break;
+ ret = nfs_commit_inode(inode, FLUSH_SYNC);
+ if (ret < 0)
+ goto out_error;
+ }
+out_error:
+ trace_nfs_writeback_page_exit(inode, ret);
+ return ret;
+}
+
+#ifdef CONFIG_MIGRATION
+int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
+ struct page *page, enum migrate_mode mode)
+{
+ /*
+ * If PagePrivate is set, then the page is currently associated with
+ * an in-progress read or write request. Don't try to migrate it.
+ *
+ * FIXME: we could do this in principle, but we'll need a way to ensure
+ * that we can safely release the inode reference while holding
+ * the page lock.
+ */
+ if (PagePrivate(page))
+ return -EBUSY;
+
+ if (!nfs_fscache_release_page(page, GFP_KERNEL))
+ return -EBUSY;
+
+ return migrate_page(mapping, newpage, page, mode);
+}
+#endif
+
+int __init nfs_init_writepagecache(void)
+{
+ nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
+ sizeof(struct nfs_pgio_header),
+ 0, SLAB_HWCACHE_ALIGN,
+ NULL);
+ if (nfs_wdata_cachep == NULL)
+ return -ENOMEM;
+
+ nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
+ nfs_wdata_cachep);
+ if (nfs_wdata_mempool == NULL)
+ goto out_destroy_write_cache;
+
+ nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
+ sizeof(struct nfs_commit_data),
+ 0, SLAB_HWCACHE_ALIGN,
+ NULL);
+ if (nfs_cdata_cachep == NULL)
+ goto out_destroy_write_mempool;
+
+ nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
+ nfs_cdata_cachep);
+ if (nfs_commit_mempool == NULL)
+ goto out_destroy_commit_cache;
+
+ /*
+ * NFS congestion size, scale with available memory.
+ *
+ * 64MB: 8192k
+ * 128MB: 11585k
+ * 256MB: 16384k
+ * 512MB: 23170k
+ * 1GB: 32768k
+ * 2GB: 46340k
+ * 4GB: 65536k
+ * 8GB: 92681k
+ * 16GB: 131072k
+ *
+ * This allows larger machines to have larger/more transfers.
+ * Limit the default to 256M
+ */
+ nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
+ if (nfs_congestion_kb > 256*1024)
+ nfs_congestion_kb = 256*1024;
+
+ return 0;
+
+out_destroy_commit_cache:
+ kmem_cache_destroy(nfs_cdata_cachep);
+out_destroy_write_mempool:
+ mempool_destroy(nfs_wdata_mempool);
+out_destroy_write_cache:
+ kmem_cache_destroy(nfs_wdata_cachep);
+ return -ENOMEM;
+}
+
+void nfs_destroy_writepagecache(void)
+{
+ mempool_destroy(nfs_commit_mempool);
+ kmem_cache_destroy(nfs_cdata_cachep);
+ mempool_destroy(nfs_wdata_mempool);
+ kmem_cache_destroy(nfs_wdata_cachep);
+}
+
+static const struct nfs_rw_ops nfs_rw_write_ops = {
+ .rw_alloc_header = nfs_writehdr_alloc,
+ .rw_free_header = nfs_writehdr_free,
+ .rw_done = nfs_writeback_done,
+ .rw_result = nfs_writeback_result,
+ .rw_initiate = nfs_initiate_write,
+};