1 files changed, 312 insertions, 304 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index f6675d2c386c..345492e78643 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -57,10 +57,13 @@
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
 #include <linux/nfs_page.h>
+#include <linux/backing-dev.h>
+
 #include <asm/uaccess.h>
 #include <linux/smp_lock.h>
 
 #include "delegation.h"
+#include "internal.h"
 #include "iostat.h"
 
 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
@@ -72,18 +75,17 @@
  * Local function declarations
  */
 static struct nfs_page * nfs_update_request(struct nfs_open_context*,
-                                            struct inode *,
                                             struct page *,
                                             unsigned int, unsigned int);
+static void nfs_mark_request_dirty(struct nfs_page *req);
 static int nfs_wait_on_write_congestion(struct address_space *, int);
 static int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int);
-static int nfs_flush_inode(struct inode *inode, unsigned long idx_start,
-                           unsigned int npages, int how);
+static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
 static const struct rpc_call_ops nfs_write_partial_ops;
 static const struct rpc_call_ops nfs_write_full_ops;
 static const struct rpc_call_ops nfs_commit_ops;
 
-static kmem_cache_t *nfs_wdata_cachep;
+static struct kmem_cache *nfs_wdata_cachep;
 static mempool_t *nfs_wdata_mempool;
 static mempool_t *nfs_commit_mempool;
 
@@ -91,7 +93,7 @@ static DECLARE_WAIT_QUEUE_HEAD(nfs_write_congestion);
 
 struct nfs_write_data *nfs_commit_alloc(void)
 {
-        struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, SLAB_NOFS);
+        struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
 
         if (p) {
                 memset(p, 0, sizeof(*p));
@@ -100,17 +102,23 @@ struct nfs_write_data *nfs_commit_alloc(void)
         return p;
 }
 
-void nfs_commit_free(struct nfs_write_data *p)
+void nfs_commit_rcu_free(struct rcu_head *head)
 {
+        struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
         if (p && (p->pagevec != &p->page_array[0]))
                 kfree(p->pagevec);
         mempool_free(p, nfs_commit_mempool);
 }
 
+void nfs_commit_free(struct nfs_write_data *wdata)
+{
+        call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free);
+}
+
 struct nfs_write_data *nfs_writedata_alloc(size_t len)
 {
         unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-        struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, SLAB_NOFS);
+        struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
 
         if (p) {
                 memset(p, 0, sizeof(*p));
@@ -129,18 +137,47 @@ struct nfs_write_data *nfs_writedata_alloc(size_t len)
         return p;
 }
 
-static void nfs_writedata_free(struct nfs_write_data *p)
+static void nfs_writedata_rcu_free(struct rcu_head *head)
 {
+        struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
         if (p && (p->pagevec != &p->page_array[0]))
                 kfree(p->pagevec);
         mempool_free(p, nfs_wdata_mempool);
 }
 
+static void nfs_writedata_free(struct nfs_write_data *wdata)
+{
+        call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
+}
+
 void nfs_writedata_release(void *wdata)
 {
         nfs_writedata_free(wdata);
 }
 
+static struct nfs_page *nfs_page_find_request_locked(struct page *page)
+{
+        struct nfs_page *req = NULL;
+
+        if (PagePrivate(page)) {
+                req = (struct nfs_page *)page_private(page);
+                if (req != NULL)
+                        atomic_inc(&req->wb_count);
+        }
+        return req;
+}
+
+static struct nfs_page *nfs_page_find_request(struct page *page)
+{
+        struct nfs_page *req = NULL;
+        spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
+
+        spin_lock(req_lock);
+        req = nfs_page_find_request_locked(page);
+        spin_unlock(req_lock);
+        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)
 {
@@ -162,113 +199,34 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
  */
 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 {
-        loff_t end_offs;
-
         if (PageUptodate(page))
                 return;
         if (base != 0)
                 return;
-        if (count == PAGE_CACHE_SIZE) {
-                SetPageUptodate(page);
+        if (count != nfs_page_length(page))
                 return;
-        }
-
-        end_offs = i_size_read(page->mapping->host) - 1;
-        if (end_offs < 0)
-                return;
-        /* Is this the last page? */
-        if (page->index != (unsigned long)(end_offs >> PAGE_CACHE_SHIFT))
-                return;
-        /* This is the last page: set PG_uptodate if we cover the entire
-         * extent of the data, then zero the rest of the page.
-         */
-        if (count == (unsigned int)(end_offs & (PAGE_CACHE_SIZE - 1)) + 1) {
+        if (count != PAGE_CACHE_SIZE)
                 memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);
-                SetPageUptodate(page);
-        }
-}
-
-/*
- * Write a page synchronously.
- * Offset is the data offset within the page.
- */
-static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode,
-                struct page *page, unsigned int offset, unsigned int count,
-                int how)
-{
-        unsigned int    wsize = NFS_SERVER(inode)->wsize;
-        int             result, written = 0;
-        struct nfs_write_data *wdata;
-
-        wdata = nfs_writedata_alloc(wsize);
-        if (!wdata)
-                return -ENOMEM;
-
-        wdata->flags = how;
-        wdata->cred = ctx->cred;
-        wdata->inode = inode;
-        wdata->args.fh = NFS_FH(inode);
-        wdata->args.context = ctx;
-        wdata->args.pages = &page;
-        wdata->args.stable = NFS_FILE_SYNC;
-        wdata->args.pgbase = offset;
-        wdata->args.count = wsize;
-        wdata->res.fattr = &wdata->fattr;
-        wdata->res.verf = &wdata->verf;
-
-        dprintk("NFS:      nfs_writepage_sync(%s/%Ld %d@%Ld)\n",
-                inode->i_sb->s_id,
-                (long long)NFS_FILEID(inode),
-                count, (long long)(page_offset(page) + offset));
-
-        set_page_writeback(page);
-        nfs_begin_data_update(inode);
-        do {
-                if (count < wsize)
-                        wdata->args.count = count;
-                wdata->args.offset = page_offset(page) + wdata->args.pgbase;
-
-                result = NFS_PROTO(inode)->write(wdata);
-
-                if (result < 0) {
-                        /* Must mark the page invalid after I/O error */
-                        ClearPageUptodate(page);
-                        goto io_error;
-                }
-                if (result < wdata->args.count)
-                        printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n",
-                                        wdata->args.count, result);
-
-                wdata->args.offset += result;
-                wdata->args.pgbase += result;
-                written += result;
-                count -= result;
-                nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, result);
-        } while (count);
-        /* Update file length */
-        nfs_grow_file(page, offset, written);
-        /* Set the PG_uptodate flag? */
-        nfs_mark_uptodate(page, offset, written);
-
-        if (PageError(page))
-                ClearPageError(page);
-
-io_error:
-        nfs_end_data_update(inode);
-        end_page_writeback(page);
-        nfs_writedata_free(wdata);
-        return written ? written : result;
+        SetPageUptodate(page);
 }
 
-static int nfs_writepage_async(struct nfs_open_context *ctx,
-                struct inode *inode, struct page *page,
+static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
                 unsigned int offset, unsigned int count)
 {
         struct nfs_page *req;
+        int ret;
 
-        req = nfs_update_request(ctx, inode, page, offset, count);
-        if (IS_ERR(req))
-                return PTR_ERR(req);
+        for (;;) {
+                req = nfs_update_request(ctx, page, offset, count);
+                if (!IS_ERR(req))
+                        break;
+                ret = PTR_ERR(req);
+                if (ret != -EBUSY)
+                        return ret;
+                ret = nfs_wb_page(page->mapping->host, page);
+                if (ret != 0)
+                        return ret;
+        }
         /* Update file length */
         nfs_grow_file(page, offset, count);
         /* Set the PG_uptodate flag? */
@@ -287,73 +245,94 @@ static int wb_priority(struct writeback_control *wbc)
 }
 
 /*
+ * Find an associated nfs write request, and prepare to flush it out
+ * Returns 1 if there was no write request, or if the request was
+ * already tagged by nfs_set_page_dirty.Returns 0 if the request
+ * was not tagged.
+ * May also return an error if the user signalled nfs_wait_on_request().
+ */
+static int nfs_page_mark_flush(struct page *page)
+{
+        struct nfs_page *req;
+        spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
+        int ret;
+
+        spin_lock(req_lock);
+        for(;;) {
+                req = nfs_page_find_request_locked(page);
+                if (req == NULL) {
+                        spin_unlock(req_lock);
+                        return 1;
+                }
+                if (nfs_lock_request_dontget(req))
+                        break;
+                /* Note: If we hold the page lock, as is the case in nfs_writepage,
+                 *       then the call to nfs_lock_request_dontget() will always
+                 *       succeed provided that someone hasn't already marked the
+                 *       request as dirty (in which case we don't care).
+                 */
+                spin_unlock(req_lock);
+                ret = nfs_wait_on_request(req);
+                nfs_release_request(req);
+                if (ret != 0)
+                        return ret;
+                spin_lock(req_lock);
+        }
+        spin_unlock(req_lock);
+        if (test_and_set_bit(PG_FLUSHING, &req->wb_flags) == 0) {
+                nfs_mark_request_dirty(req);
+                set_page_writeback(page);
+        }
+        ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
+        nfs_unlock_request(req);
+        return ret;
+}
+
+/*
  * Write an mmapped page to the server.
  */
-int nfs_writepage(struct page *page, struct writeback_control *wbc)
+static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 {
         struct nfs_open_context *ctx;
         struct inode *inode = page->mapping->host;
-        unsigned long end_index;
-        unsigned offset = PAGE_CACHE_SIZE;
-        loff_t i_size = i_size_read(inode);
-        int inode_referenced = 0;
-        int priority = wb_priority(wbc);
+        unsigned offset;
         int err;
 
         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 
-        /*
-         * Note: We need to ensure that we have a reference to the inode
-         *       if we are to do asynchronous writes. If not, waiting
-         *       in nfs_wait_on_request() may deadlock with clear_inode().
-         *
-         *       If igrab() fails here, then it is in any case safe to
-         *       call nfs_wb_page(), since there will be no pending writes.
-         */
-        if (igrab(inode) != 0)
-                inode_referenced = 1;
-        end_index = i_size >> PAGE_CACHE_SHIFT;
-
-        /* Ensure we've flushed out any previous writes */
-        nfs_wb_page_priority(inode, page, priority);
-
-        /* easy case */
-        if (page->index < end_index)
-                goto do_it;
-        /* things got complicated... */
-        offset = i_size & (PAGE_CACHE_SIZE-1);
-
-        /* OK, are we completely out? */
-        err = 0; /* potential race with truncate - ignore */
-        if (page->index >= end_index+1 || !offset)
+        err = nfs_page_mark_flush(page);
+        if (err <= 0)
+                goto out;
+        err = 0;
+        offset = nfs_page_length(page);
+        if (!offset)
                 goto out;
-do_it:
+
         ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
         if (ctx == NULL) {
                 err = -EBADF;
                 goto out;
         }
-        lock_kernel();
-        if (!IS_SYNC(inode) && inode_referenced) {
-                err = nfs_writepage_async(ctx, inode, page, 0, offset);
-                if (!wbc->for_writepages)
-                        nfs_flush_inode(inode, 0, 0, wb_priority(wbc));
-        } else {
-                err = nfs_writepage_sync(ctx, inode, page, 0,
-                                                offset, priority);
-                if (err >= 0) {
-                        if (err != offset)
-                                redirty_page_for_writepage(wbc, page);
-                        err = 0;
-                }
-        }
-        unlock_kernel();
+        err = nfs_writepage_setup(ctx, page, 0, offset);
         put_nfs_open_context(ctx);
+        if (err != 0)
+                goto out;
+        err = nfs_page_mark_flush(page);
+        if (err > 0)
+                err = 0;
 out:
+        if (!wbc->for_writepages)
+                nfs_flush_mapping(page->mapping, wbc, wb_priority(wbc));
+        return err;
+}
+
+int nfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+        int err;
+
+        err = nfs_writepage_locked(page, wbc);
         unlock_page(page);
-        if (inode_referenced)
-                iput(inode);
         return err; 
 }
 
@@ -377,25 +356,22 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
                         return 0;
                 nfs_wait_on_write_congestion(mapping, 0);
         }
-        err = nfs_flush_inode(inode, 0, 0, wb_priority(wbc));
+        err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc));
         if (err < 0)
                 goto out;
         nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
-        wbc->nr_to_write -= err;
         if (!wbc->nonblocking && wbc->sync_mode == WB_SYNC_ALL) {
                 err = nfs_wait_on_requests(inode, 0, 0);
                 if (err < 0)
                         goto out;
         }
         err = nfs_commit_inode(inode, wb_priority(wbc));
-        if (err > 0) {
-                wbc->nr_to_write -= err;
+        if (err > 0)
                 err = 0;
-        }
 out:
         clear_bit(BDI_write_congested, &bdi->state);
         wake_up_all(&nfs_write_congestion);
-        writeback_congestion_end();
+        congestion_end(WRITE);
         return err;
 }
 
@@ -418,6 +394,7 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
                         nfsi->change_attr++;
         }
         SetPagePrivate(req->wb_page);
+        set_page_private(req->wb_page, (unsigned long)req);
         nfsi->npages++;
         atomic_inc(&req->wb_count);
         return 0;
@@ -434,6 +411,7 @@ static void nfs_inode_remove_request(struct nfs_page *req)
         BUG_ON (!NFS_WBACK_BUSY(req));
 
         spin_lock(&nfsi->req_lock);
+        set_page_private(req->wb_page, 0);
         ClearPagePrivate(req->wb_page);
         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
         nfsi->npages--;
@@ -448,33 +426,6 @@ static void nfs_inode_remove_request(struct nfs_page *req)
 }
 
 /*
- * Find a request
- */
-static inline struct nfs_page *
-_nfs_find_request(struct inode *inode, unsigned long index)
-{
-        struct nfs_inode *nfsi = NFS_I(inode);
-        struct nfs_page *req;
-
-        req = (struct nfs_page*)radix_tree_lookup(&nfsi->nfs_page_tree, index);
-        if (req)
-                atomic_inc(&req->wb_count);
-        return req;
-}
-
-static struct nfs_page *
-nfs_find_request(struct inode *inode, unsigned long index)
-{
-        struct nfs_page         *req;
-        struct nfs_inode        *nfsi = NFS_I(inode);
-
-        spin_lock(&nfsi->req_lock);
-        req = _nfs_find_request(inode, index);
-        spin_unlock(&nfsi->req_lock);
-        return req;
-}
-
-/*
  * Add a request to the inode's dirty list.
  */
 static void
@@ -489,8 +440,14 @@ nfs_mark_request_dirty(struct nfs_page *req)
         nfs_list_add_request(req, &nfsi->dirty);
         nfsi->ndirty++;
         spin_unlock(&nfsi->req_lock);
-        inc_zone_page_state(req->wb_page, NR_FILE_DIRTY);
-        mark_inode_dirty(inode);
+        __mark_inode_dirty(inode, I_DIRTY_PAGES);
+}
+
+static void
+nfs_redirty_request(struct nfs_page *req)
+{
+        clear_bit(PG_FLUSHING, &req->wb_flags);
+        __set_page_dirty_nobuffers(req->wb_page);
 }
 
 /*
@@ -499,8 +456,7 @@ nfs_mark_request_dirty(struct nfs_page *req)
 static inline int
 nfs_dirty_request(struct nfs_page *req)
 {
-        struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
-        return !list_empty(&req->wb_list) && req->wb_list_head == &nfsi->dirty;
+        return test_bit(PG_FLUSHING, &req->wb_flags) == 0;
 }
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
@@ -518,7 +474,7 @@ nfs_mark_request_commit(struct nfs_page *req)
         nfsi->ncommit++;
         spin_unlock(&nfsi->req_lock);
         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
-        mark_inode_dirty(inode);
+        __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
 #endif
 
@@ -588,36 +544,11 @@ static void nfs_cancel_commit_list(struct list_head *head)
 
         while(!list_empty(head)) {
                 req = nfs_list_entry(head->next);
+                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
                 nfs_list_remove_request(req);
                 nfs_inode_remove_request(req);
-                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
-                nfs_clear_page_writeback(req);
-        }
-}
-
-/*
- * nfs_scan_dirty - Scan an inode for dirty requests
- * @inode: NFS inode to scan
- * @dst: destination list
- * @idx_start: lower bound of page->index to scan.
- * @npages: idx_start + npages sets the upper bound to scan.
- *
- * Moves requests from the inode's dirty page list.
- * The requests are *not* checked to ensure that they form a contiguous set.
- */
-static int
-nfs_scan_dirty(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
-{
-        struct nfs_inode *nfsi = NFS_I(inode);
-        int res = 0;
-
-        if (nfsi->ndirty != 0) {
-                res = nfs_scan_lock_dirty(nfsi, dst, idx_start, npages);
-                nfsi->ndirty -= res;
-                if ((nfsi->ndirty == 0) != list_empty(&nfsi->dirty))
-                        printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
+                nfs_unlock_request(req);
         }
-        return res;
 }
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
@@ -696,27 +627,27 @@ static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
  * Note: Should always be called with the Page Lock held!
  */
 static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
-                struct inode *inode, struct page *page,
-                unsigned int offset, unsigned int bytes)
+                struct page *page, unsigned int offset, unsigned int bytes)
 {
-        struct nfs_server *server = NFS_SERVER(inode);
+        struct inode *inode = page->mapping->host;
         struct nfs_inode *nfsi = NFS_I(inode);
         struct nfs_page         *req, *new = NULL;
         unsigned long           rqend, end;
 
         end = offset + bytes;
 
-        if (nfs_wait_on_write_congestion(page->mapping, server->flags & NFS_MOUNT_INTR))
+        if (nfs_wait_on_write_congestion(page->mapping, NFS_SERVER(inode)->flags & NFS_MOUNT_INTR))
                 return ERR_PTR(-ERESTARTSYS);
         for (;;) {
                 /* Loop over all inode entries and see if we find
                  * A request for the page we wish to update
                  */
                 spin_lock(&nfsi->req_lock);
-                req = _nfs_find_request(inode, page->index);
+                req = nfs_page_find_request_locked(page);
                 if (req) {
                         if (!nfs_lock_request_dontget(req)) {
                                 int error;
+
                                 spin_unlock(&nfsi->req_lock);
                                 error = nfs_wait_on_request(req);
                                 nfs_release_request(req);
@@ -743,7 +674,6 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
                                 return ERR_PTR(error);
                         }
                         spin_unlock(&nfsi->req_lock);
-                        nfs_mark_request_dirty(new);
                         return new;
                 }
                 spin_unlock(&nfsi->req_lock);
@@ -784,9 +714,8 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
 int nfs_flush_incompatible(struct file *file, struct page *page)
 {
         struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
-        struct inode    *inode = page->mapping->host;
         struct nfs_page *req;
-        int             status = 0;
+        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
@@ -795,13 +724,18 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
          * Also do the same if we find a request from an existing
          * dropped page.
          */
-        req = nfs_find_request(inode, page->index);
-        if (req) {
-                if (req->wb_page != page || ctx != req->wb_context)
-                        status = nfs_wb_page(inode, page);
+        do {
+                req = nfs_page_find_request(page);
+                if (req == NULL)
+                        return 0;
+                do_flush = req->wb_page != page || req->wb_context != ctx
+                        || !nfs_dirty_request(req);
                 nfs_release_request(req);
-        }
-        return (status < 0) ? status : 0;
+                if (!do_flush)
+                        return 0;
+                status = nfs_wb_page(page->mapping->host, page);
+        } while (status == 0);
+        return status;
 }
 
 /*
@@ -815,72 +749,27 @@ int nfs_updatepage(struct file *file, struct page *page,
 {
         struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
         struct inode    *inode = page->mapping->host;
-        struct nfs_page *req;
         int             status = 0;
 
         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 
         dprintk("NFS:      nfs_updatepage(%s/%s %d@%Ld)\n",
-                file->f_dentry->d_parent->d_name.name,
-                file->f_dentry->d_name.name, count,
+                file->f_path.dentry->d_parent->d_name.name,
+                file->f_path.dentry->d_name.name, count,
                 (long long)(page_offset(page) +offset));
 
-        if (IS_SYNC(inode)) {
-                status = nfs_writepage_sync(ctx, inode, page, offset, count, 0);
-                if (status > 0) {
-                        if (offset == 0 && status == PAGE_CACHE_SIZE)
-                                SetPageUptodate(page);
-                        return 0;
-                }
-                return status;
-        }
-
         /* If we're not using byte range locks, and we know the page
          * is entirely in cache, it may be more efficient to avoid
          * fragmenting write requests.
          */
         if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) {
-                loff_t end_offs = i_size_read(inode) - 1;
-                unsigned long end_index = end_offs >> PAGE_CACHE_SHIFT;
-
-                count += offset;
+                count = max(count + offset, nfs_page_length(page));
                 offset = 0;
-                if (unlikely(end_offs < 0)) {
-                        /* Do nothing */
-                } else if (page->index == end_index) {
-                        unsigned int pglen;
-                        pglen = (unsigned int)(end_offs & (PAGE_CACHE_SIZE-1)) + 1;
-                        if (count < pglen)
-                                count = pglen;
-                } else if (page->index < end_index)
-                        count = PAGE_CACHE_SIZE;
         }
 
-        /*
-         * Try to find an NFS request corresponding to this page
-         * and update it.
-         * If the existing request cannot be updated, we must flush
-         * it out now.
-         */
-        do {
-                req = nfs_update_request(ctx, inode, page, offset, count);
-                status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
-                if (status != -EBUSY)
-                        break;
-                /* Request could not be updated. Flush it out and try again */
-                status = nfs_wb_page(inode, page);
-        } while (status >= 0);
-        if (status < 0)
-                goto done;
+        status = nfs_writepage_setup(ctx, page, offset, count);
+        __set_page_dirty_nobuffers(page);
 
-        status = 0;
-
-        /* Update file length */
-        nfs_grow_file(page, offset, count);
-        /* Set the PG_uptodate flag? */
-        nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
-        nfs_unlock_request(req);
-done:
         dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
                         status, (long long)i_size_read(inode));
         if (status < 0)
@@ -895,7 +784,7 @@ static void nfs_writepage_release(struct nfs_page *req)
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
         if (!PageError(req->wb_page)) {
                 if (NFS_NEED_RESCHED(req)) {
-                        nfs_mark_request_dirty(req);
+                        nfs_redirty_request(req);
                         goto out;
                 } else if (NFS_NEED_COMMIT(req)) {
                         nfs_mark_request_commit(req);
@@ -977,9 +866,7 @@ static void nfs_execute_write(struct nfs_write_data *data)
         sigset_t oldset;
 
         rpc_clnt_sigmask(clnt, &oldset);
-        lock_kernel();
         rpc_execute(&data->task);
-        unlock_kernel();
         rpc_clnt_sigunmask(clnt, &oldset);
 }
 
@@ -1013,7 +900,6 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
         atomic_set(&req->wb_complete, requests);
 
         ClearPageError(page);
-        set_page_writeback(page);
         offset = 0;
         nbytes = req->wb_bytes;
         do {
@@ -1041,9 +927,9 @@ out_bad:
         while (!list_empty(&list)) {
                 data = list_entry(list.next, struct nfs_write_data, pages);
                 list_del(&data->pages);
-                nfs_writedata_free(data);
+                nfs_writedata_release(data);
         }
-        nfs_mark_request_dirty(req);
+        nfs_redirty_request(req);
         nfs_clear_page_writeback(req);
         return -ENOMEM;
 }
@@ -1074,7 +960,6 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
                 nfs_list_remove_request(req);
                 nfs_list_add_request(req, &data->pages);
                 ClearPageError(req->wb_page);
-                set_page_writeback(req->wb_page);
                 *pages++ = req->wb_page;
                 count += req->wb_bytes;
         }
@@ -1089,7 +974,7 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
         while (!list_empty(head)) {
                 struct nfs_page *req = nfs_list_entry(head->next);
                 nfs_list_remove_request(req);
-                nfs_mark_request_dirty(req);
+                nfs_redirty_request(req);
                 nfs_clear_page_writeback(req);
         }
         return -ENOMEM;
@@ -1124,7 +1009,7 @@ out_err:
         while (!list_empty(head)) {
                 req = nfs_list_entry(head->next);
                 nfs_list_remove_request(req);
-                nfs_mark_request_dirty(req);
+                nfs_redirty_request(req);
                 nfs_clear_page_writeback(req);
         }
         return error;
@@ -1440,7 +1325,7 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata)
                 }
                 /* We have a mismatch. Write the page again */
                 dprintk(" mismatch\n");
-                nfs_mark_request_dirty(req);
+                nfs_redirty_request(req);
         next:
                 nfs_clear_page_writeback(req);
         }
@@ -1457,18 +1342,17 @@ static inline int nfs_commit_list(struct inode *inode, struct list_head *head, i
 }
 #endif
 
-static int nfs_flush_inode(struct inode *inode, unsigned long idx_start,
-                           unsigned int npages, int how)
+static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
 {
-        struct nfs_inode *nfsi = NFS_I(inode);
+        struct nfs_inode *nfsi = NFS_I(mapping->host);
         LIST_HEAD(head);
-        int res;
+        long res;
 
         spin_lock(&nfsi->req_lock);
-        res = nfs_scan_dirty(inode, &head, idx_start, npages);
+        res = nfs_scan_dirty(mapping, wbc, &head);
         spin_unlock(&nfsi->req_lock);
         if (res) {
-                int error = nfs_flush_list(inode, &head, res, how);
+                int error = nfs_flush_list(mapping->host, &head, res, how);
                 if (error < 0)
                         return error;
         }
@@ -1494,38 +1378,62 @@ int nfs_commit_inode(struct inode *inode, int how)
 }
 #endif
 
-int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
-                unsigned int npages, int how)
+long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_control *wbc, int how)
 {
+        struct inode *inode = mapping->host;
         struct nfs_inode *nfsi = NFS_I(inode);
+        unsigned long idx_start, idx_end;
+        unsigned int npages = 0;
         LIST_HEAD(head);
         int nocommit = how & FLUSH_NOCOMMIT;
-        int pages, ret;
-
+        long pages, ret;
+
+        /* FIXME */
+        if (wbc->range_cyclic)
+                idx_start = 0;
+        else {
+                idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
+                idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
+                if (idx_end > idx_start) {
+                        unsigned long l_npages = 1 + idx_end - idx_start;
+                        npages = l_npages;
+                        if (sizeof(npages) != sizeof(l_npages) &&
+                                        (unsigned long)npages != l_npages)
+                                npages = 0;
+                }
+        }
         how &= ~FLUSH_NOCOMMIT;
         spin_lock(&nfsi->req_lock);
         do {
+                wbc->pages_skipped = 0;
                 ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
                 if (ret != 0)
                         continue;
-                pages = nfs_scan_dirty(inode, &head, idx_start, npages);
+                pages = nfs_scan_dirty(mapping, wbc, &head);
                 if (pages != 0) {
                         spin_unlock(&nfsi->req_lock);
-                        if (how & FLUSH_INVALIDATE)
+                        if (how & FLUSH_INVALIDATE) {
                                 nfs_cancel_dirty_list(&head);
-                        else
+                                ret = pages;
+                        } else
                                 ret = nfs_flush_list(inode, &head, pages, how);
                         spin_lock(&nfsi->req_lock);
                         continue;
                 }
+                if (wbc->pages_skipped != 0)
+                        continue;
                 if (nocommit)
                         break;
                 pages = nfs_scan_commit(inode, &head, idx_start, npages);
-                if (pages == 0)
+                if (pages == 0) {
+                        if (wbc->pages_skipped != 0)
+                                continue;
                         break;
+                }
                 if (how & FLUSH_INVALIDATE) {
                         spin_unlock(&nfsi->req_lock);
                         nfs_cancel_commit_list(&head);
+                        ret = pages;
                         spin_lock(&nfsi->req_lock);
                         continue;
                 }
@@ -1538,6 +1446,106 @@ int nfs_sync_inode_wait(struct inode *inode, unsigned long idx_start,
         return ret;
 }
 
+/*
+ * flush the inode to disk.
+ */
+int nfs_wb_all(struct inode *inode)
+{
+        struct address_space *mapping = inode->i_mapping;
+        struct writeback_control wbc = {
+                .bdi = mapping->backing_dev_info,
+                .sync_mode = WB_SYNC_ALL,
+                .nr_to_write = LONG_MAX,
+                .for_writepages = 1,
+                .range_cyclic = 1,
+        };
+        int ret;
+
+        ret = generic_writepages(mapping, &wbc);
+        if (ret < 0)
+                goto out;
+        ret = nfs_sync_mapping_wait(mapping, &wbc, 0);
+        if (ret >= 0)
+                return 0;
+out:
+        __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+        return ret;
+}
+
+int nfs_sync_mapping_range(struct address_space *mapping, loff_t range_start, loff_t range_end, int how)
+{
+        struct writeback_control wbc = {
+                .bdi = mapping->backing_dev_info,
+                .sync_mode = WB_SYNC_ALL,
+                .nr_to_write = LONG_MAX,
+                .range_start = range_start,
+                .range_end = range_end,
+                .for_writepages = 1,
+        };
+        int ret;
+
+        if (!(how & FLUSH_NOWRITEPAGE)) {
+                ret = generic_writepages(mapping, &wbc);
+                if (ret < 0)
+                        goto out;
+        }
+        ret = nfs_sync_mapping_wait(mapping, &wbc, how);
+        if (ret >= 0)
+                return 0;
+out:
+        __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+        return ret;
+}
+
+int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
+{
+        loff_t range_start = page_offset(page);
+        loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
+        struct writeback_control wbc = {
+                .bdi = page->mapping->backing_dev_info,
+                .sync_mode = WB_SYNC_ALL,
+                .nr_to_write = LONG_MAX,
+                .range_start = range_start,
+                .range_end = range_end,
+        };
+        int ret;
+
+        BUG_ON(!PageLocked(page));
+        if (!(how & FLUSH_NOWRITEPAGE) && clear_page_dirty_for_io(page)) {
+                ret = nfs_writepage_locked(page, &wbc);
+                if (ret < 0)
+                        goto out;
+        }
+        ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
+        if (ret >= 0)
+                return 0;
+out:
+        __mark_inode_dirty(inode, I_DIRTY_PAGES);
+        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)
+{
+        return nfs_wb_page_priority(inode, page, FLUSH_STABLE);
+}
+
+int nfs_set_page_dirty(struct page *page)
+{
+        struct nfs_page *req;
+
+        req = nfs_page_find_request(page);
+        if (req != NULL) {
+                /* Mark any existing write requests for flushing */
+                set_bit(PG_NEED_FLUSH, &req->wb_flags);
+                nfs_release_request(req);
+        }
+        return __set_page_dirty_nobuffers(page);
+}
+
+
 int __init nfs_init_writepagecache(void)
 {
         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",