Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[cascardo/linux.git] / fs / nfs / write.c
index dea1737..5d44b8b 100644 (file)
@@ -12,6 +12,7 @@
 #include <linux/pagemap.h>
 #include <linux/file.h>
 #include <linux/writeback.h>
+#include <linux/swap.h>
 
 #include <linux/sunrpc/clnt.h>
 #include <linux/nfs_fs.h>
@@ -37,9 +38,8 @@
 static struct nfs_page * nfs_update_request(struct nfs_open_context*,
                                            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 long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
+static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
+                                 struct inode *inode, int ioflags);
 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;
@@ -48,8 +48,6 @@ static struct kmem_cache *nfs_wdata_cachep;
 static mempool_t *nfs_wdata_mempool;
 static mempool_t *nfs_commit_mempool;
 
-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, GFP_NOFS);
@@ -74,9 +72,8 @@ 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)
+struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
 {
-       unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
        struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
 
        if (p) {
@@ -142,7 +139,7 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
 {
        struct inode *inode = page->mapping->host;
        loff_t end, i_size = i_size_read(inode);
-       unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+       pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 
        if (i_size > 0 && page->index < end_index)
                return;
@@ -153,6 +150,13 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
        i_size_write(inode, end);
 }
 
+/* A writeback failed: mark the page as bad, and invalidate the page cache */
+static void nfs_set_pageerror(struct page *page)
+{
+       SetPageError(page);
+       nfs_zap_mapping(page->mapping->host, page->mapping);
+}
+
 /* We can set the PG_uptodate flag if we see that a write request
  * covers the full page.
  */
@@ -197,12 +201,49 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 static int wb_priority(struct writeback_control *wbc)
 {
        if (wbc->for_reclaim)
-               return FLUSH_HIGHPRI;
+               return FLUSH_HIGHPRI | FLUSH_STABLE;
        if (wbc->for_kupdate)
                return FLUSH_LOWPRI;
        return 0;
 }
 
+/*
+ * 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 int nfs_set_page_writeback(struct page *page)
+{
+       int ret = test_set_page_writeback(page);
+
+       if (!ret) {
+               struct inode *inode = page->mapping->host;
+               struct nfs_server *nfss = NFS_SERVER(inode);
+
+               if (atomic_inc_return(&nfss->writeback) >
+                               NFS_CONGESTION_ON_THRESH)
+                       set_bdi_congested(&nfss->backing_dev_info, WRITE);
+       }
+       return ret;
+}
+
+static void nfs_end_page_writeback(struct page *page)
+{
+       struct inode *inode = page->mapping->host;
+       struct nfs_server *nfss = NFS_SERVER(inode);
+
+       end_page_writeback(page);
+       if (atomic_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) {
+               clear_bdi_congested(&nfss->backing_dev_info, WRITE);
+               congestion_end(WRITE);
+       }
+}
+
 /*
  * 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
@@ -210,10 +251,12 @@ static int wb_priority(struct writeback_control *wbc)
  * 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)
+static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
+                               struct page *page)
 {
        struct nfs_page *req;
-       spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
+       struct nfs_inode *nfsi = NFS_I(page->mapping->host);
+       spinlock_t *req_lock = &nfsi->req_lock;
        int ret;
 
        spin_lock(req_lock);
@@ -231,19 +274,30 @@ static int nfs_page_mark_flush(struct page *page)
                 *       request as dirty (in which case we don't care).
                 */
                spin_unlock(req_lock);
+               /* Prevent deadlock! */
+               nfs_pageio_complete(pgio);
                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);
+       if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+               /* This request is marked for commit */
+               spin_unlock(req_lock);
+               nfs_unlock_request(req);
+               nfs_pageio_complete(pgio);
+               return 1;
+       }
+       if (nfs_set_page_writeback(page) != 0) {
+               spin_unlock(req_lock);
+               BUG();
        }
+       radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
+                       NFS_PAGE_TAG_WRITEBACK);
        ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
-       nfs_unlock_request(req);
+       spin_unlock(req_lock);
+       nfs_pageio_add_request(pgio, req);
        return ret;
 }
 
@@ -252,6 +306,7 @@ static int nfs_page_mark_flush(struct page *page)
  */
 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 {
+       struct nfs_pageio_descriptor mypgio, *pgio;
        struct nfs_open_context *ctx;
        struct inode *inode = page->mapping->host;
        unsigned offset;
@@ -260,7 +315,14 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
        nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
        nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 
-       err = nfs_page_mark_flush(page);
+       if (wbc->for_writepages)
+               pgio = wbc->fs_private;
+       else {
+               nfs_pageio_init_write(&mypgio, inode, wb_priority(wbc));
+               pgio = &mypgio;
+       }
+
+       err = nfs_page_async_flush(pgio, page);
        if (err <= 0)
                goto out;
        err = 0;
@@ -277,12 +339,12 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
        put_nfs_open_context(ctx);
        if (err != 0)
                goto out;
-       err = nfs_page_mark_flush(page);
+       err = nfs_page_async_flush(pgio, page);
        if (err > 0)
                err = 0;
 out:
        if (!wbc->for_writepages)
-               nfs_flush_mapping(page->mapping, wbc, FLUSH_STABLE|wb_priority(wbc));
+               nfs_pageio_complete(pgio);
        return err;
 }
 
@@ -295,36 +357,23 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc)
        return err; 
 }
 
-/*
- * Note: causes nfs_update_request() to block on the assumption
- *      that the writeback is generated due to memory pressure.
- */
 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 {
-       struct backing_dev_info *bdi = mapping->backing_dev_info;
        struct inode *inode = mapping->host;
+       struct nfs_pageio_descriptor pgio;
        int err;
 
        nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 
+       nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
+       wbc->fs_private = &pgio;
        err = generic_writepages(mapping, wbc);
+       nfs_pageio_complete(&pgio);
        if (err)
                return err;
-       while (test_and_set_bit(BDI_write_congested, &bdi->state) != 0) {
-               if (wbc->nonblocking)
-                       return 0;
-               nfs_wait_on_write_congestion(mapping, 0);
-       }
-       err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc));
-       if (err < 0)
-               goto out;
-       nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
-       err = 0;
-out:
-       clear_bit(BDI_write_congested, &bdi->state);
-       wake_up_all(&nfs_write_congestion);
-       congestion_end(WRITE);
-       return err;
+       if (pgio.pg_error)
+               return pgio.pg_error;
+       return 0;
 }
 
 /*
@@ -347,13 +396,15 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
        }
        SetPagePrivate(req->wb_page);
        set_page_private(req->wb_page, (unsigned long)req);
+       if (PageDirty(req->wb_page))
+               set_bit(PG_NEED_FLUSH, &req->wb_flags);
        nfsi->npages++;
        atomic_inc(&req->wb_count);
        return 0;
 }
 
 /*
- * Insert a write request into an inode
+ * Remove a write request from an inode
  */
 static void nfs_inode_remove_request(struct nfs_page *req)
 {
@@ -366,6 +417,8 @@ static void nfs_inode_remove_request(struct nfs_page *req)
        set_page_private(req->wb_page, 0);
        ClearPagePrivate(req->wb_page);
        radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
+       if (test_and_clear_bit(PG_NEED_FLUSH, &req->wb_flags))
+               __set_page_dirty_nobuffers(req->wb_page);
        nfsi->npages--;
        if (!nfsi->npages) {
                spin_unlock(&nfsi->req_lock);
@@ -377,28 +430,9 @@ static void nfs_inode_remove_request(struct nfs_page *req)
        nfs_release_request(req);
 }
 
-/*
- * Add a request to the inode's dirty list.
- */
-static void
-nfs_mark_request_dirty(struct nfs_page *req)
-{
-       struct inode *inode = req->wb_context->dentry->d_inode;
-       struct nfs_inode *nfsi = NFS_I(inode);
-
-       spin_lock(&nfsi->req_lock);
-       radix_tree_tag_set(&nfsi->nfs_page_tree,
-                       req->wb_index, NFS_PAGE_TAG_DIRTY);
-       nfs_list_add_request(req, &nfsi->dirty);
-       nfsi->ndirty++;
-       spin_unlock(&nfsi->req_lock);
-       __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);
 }
 
@@ -408,7 +442,11 @@ nfs_redirty_request(struct nfs_page *req)
 static inline int
 nfs_dirty_request(struct nfs_page *req)
 {
-       return test_bit(PG_FLUSHING, &req->wb_flags) == 0;
+       struct page *page = req->wb_page;
+
+       if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))
+               return 0;
+       return !PageWriteback(req->wb_page);
 }
 
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
@@ -424,10 +462,48 @@ nfs_mark_request_commit(struct nfs_page *req)
        spin_lock(&nfsi->req_lock);
        nfs_list_add_request(req, &nfsi->commit);
        nfsi->ncommit++;
+       set_bit(PG_NEED_COMMIT, &(req)->wb_flags);
        spin_unlock(&nfsi->req_lock);
        inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
        __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
+
+static inline
+int nfs_write_need_commit(struct nfs_write_data *data)
+{
+       return data->verf.committed != NFS_FILE_SYNC;
+}
+
+static inline
+int nfs_reschedule_unstable_write(struct nfs_page *req)
+{
+       if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+               nfs_mark_request_commit(req);
+               return 1;
+       }
+       if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
+               nfs_redirty_request(req);
+               return 1;
+       }
+       return 0;
+}
+#else
+static inline void
+nfs_mark_request_commit(struct nfs_page *req)
+{
+}
+
+static inline
+int nfs_write_need_commit(struct nfs_write_data *data)
+{
+       return 0;
+}
+
+static inline
+int nfs_reschedule_unstable_write(struct nfs_page *req)
+{
+       return 0;
+}
 #endif
 
 /*
@@ -435,11 +511,11 @@ nfs_mark_request_commit(struct nfs_page *req)
  *
  * Interruptible by signals only if mounted with intr flag.
  */
-static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_start, unsigned int npages)
+static int nfs_wait_on_requests_locked(struct inode *inode, pgoff_t idx_start, unsigned int npages)
 {
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs_page *req;
-       unsigned long           idx_end, next;
+       pgoff_t idx_end, next;
        unsigned int            res = 0;
        int                     error;
 
@@ -468,17 +544,6 @@ static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_st
        return res;
 }
 
-static void nfs_cancel_dirty_list(struct list_head *head)
-{
-       struct nfs_page *req;
-       while(!list_empty(head)) {
-               req = nfs_list_entry(head->next);
-               nfs_list_remove_request(req);
-               nfs_inode_remove_request(req);
-               nfs_clear_page_writeback(req);
-       }
-}
-
 static void nfs_cancel_commit_list(struct list_head *head)
 {
        struct nfs_page *req;
@@ -487,6 +552,7 @@ static void nfs_cancel_commit_list(struct list_head *head)
                req = nfs_list_entry(head->next);
                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
                nfs_list_remove_request(req);
+               clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
                nfs_inode_remove_request(req);
                nfs_unlock_request(req);
        }
@@ -504,7 +570,7 @@ static void nfs_cancel_commit_list(struct list_head *head)
  * The requests are *not* checked to ensure that they form a contiguous set.
  */
 static int
-nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
+nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 {
        struct nfs_inode *nfsi = NFS_I(inode);
        int res = 0;
@@ -518,48 +584,12 @@ nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_st
        return res;
 }
 #else
-static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
+static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 {
        return 0;
 }
 #endif
 
-static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
-{
-       struct backing_dev_info *bdi = mapping->backing_dev_info;
-       DEFINE_WAIT(wait);
-       int ret = 0;
-
-       might_sleep();
-
-       if (!bdi_write_congested(bdi))
-               return 0;
-
-       nfs_inc_stats(mapping->host, NFSIOS_CONGESTIONWAIT);
-
-       if (intr) {
-               struct rpc_clnt *clnt = NFS_CLIENT(mapping->host);
-               sigset_t oldset;
-
-               rpc_clnt_sigmask(clnt, &oldset);
-               prepare_to_wait(&nfs_write_congestion, &wait, TASK_INTERRUPTIBLE);
-               if (bdi_write_congested(bdi)) {
-                       if (signalled())
-                               ret = -ERESTARTSYS;
-                       else
-                               schedule();
-               }
-               rpc_clnt_sigunmask(clnt, &oldset);
-       } else {
-               prepare_to_wait(&nfs_write_congestion, &wait, TASK_UNINTERRUPTIBLE);
-               if (bdi_write_congested(bdi))
-                       schedule();
-       }
-       finish_wait(&nfs_write_congestion, &wait);
-       return ret;
-}
-
-
 /*
  * Try to update any existing write request, or create one if there is none.
  * In order to match, the request's credentials must match those of
@@ -570,15 +600,14 @@ static int nfs_wait_on_write_congestion(struct address_space *mapping, int intr)
 static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
                struct page *page, unsigned int offset, unsigned int bytes)
 {
-       struct inode *inode = page->mapping->host;
+       struct address_space *mapping = page->mapping;
+       struct inode *inode = mapping->host;
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs_page         *req, *new = NULL;
-       unsigned long           rqend, end;
+       pgoff_t         rqend, end;
 
        end = offset + bytes;
 
-       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
@@ -714,32 +743,18 @@ int nfs_updatepage(struct file *file, struct page *page,
         dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
                        status, (long long)i_size_read(inode));
        if (status < 0)
-               ClearPageUptodate(page);
+               nfs_set_pageerror(page);
        return status;
 }
 
 static void nfs_writepage_release(struct nfs_page *req)
 {
-       end_page_writeback(req->wb_page);
 
-#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-       if (!PageError(req->wb_page)) {
-               if (NFS_NEED_RESCHED(req)) {
-                       nfs_redirty_request(req);
-                       goto out;
-               } else if (NFS_NEED_COMMIT(req)) {
-                       nfs_mark_request_commit(req);
-                       goto out;
-               }
-       }
-       nfs_inode_remove_request(req);
-
-out:
-       nfs_clear_commit(req);
-       nfs_clear_reschedule(req);
-#else
-       nfs_inode_remove_request(req);
-#endif
+       if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
+               nfs_end_page_writeback(req->wb_page);
+               nfs_inode_remove_request(req);
+       } else
+               nfs_end_page_writeback(req->wb_page);
        nfs_clear_page_writeback(req);
 }
 
@@ -816,7 +831,7 @@ static void nfs_execute_write(struct nfs_write_data *data)
  * Generate multiple small requests to write out a single
  * contiguous dirty area on one page.
  */
-static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
+static int nfs_flush_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 {
        struct nfs_page *req = nfs_list_entry(head->next);
        struct page *page = req->wb_page;
@@ -828,11 +843,11 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
 
        nfs_list_remove_request(req);
 
-       nbytes = req->wb_bytes;
+       nbytes = count;
        do {
                size_t len = min(nbytes, wsize);
 
-               data = nfs_writedata_alloc(len);
+               data = nfs_writedata_alloc(1);
                if (!data)
                        goto out_bad;
                list_add(&data->pages, &list);
@@ -843,23 +858,19 @@ static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
 
        ClearPageError(page);
        offset = 0;
-       nbytes = req->wb_bytes;
+       nbytes = count;
        do {
                data = list_entry(list.next, struct nfs_write_data, pages);
                list_del_init(&data->pages);
 
                data->pagevec[0] = page;
 
-               if (nbytes > wsize) {
-                       nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
-                                       wsize, offset, how);
-                       offset += wsize;
-                       nbytes -= wsize;
-               } else {
-                       nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
-                                       nbytes, offset, how);
-                       nbytes = 0;
-               }
+               if (nbytes < wsize)
+                       wsize = nbytes;
+               nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
+                                  wsize, offset, how);
+               offset += wsize;
+               nbytes -= wsize;
                nfs_execute_write(data);
        } while (nbytes != 0);
 
@@ -872,6 +883,7 @@ out_bad:
                nfs_writedata_release(data);
        }
        nfs_redirty_request(req);
+       nfs_end_page_writeback(req->wb_page);
        nfs_clear_page_writeback(req);
        return -ENOMEM;
 }
@@ -884,26 +896,23 @@ out_bad:
  * This is the case if nfs_updatepage detects a conflicting request
  * that has been written but not committed.
  */
-static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
+static int nfs_flush_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 {
        struct nfs_page         *req;
        struct page             **pages;
        struct nfs_write_data   *data;
-       unsigned int            count;
 
-       data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize);
+       data = nfs_writedata_alloc(npages);
        if (!data)
                goto out_bad;
 
        pages = data->pagevec;
-       count = 0;
        while (!list_empty(head)) {
                req = nfs_list_entry(head->next);
                nfs_list_remove_request(req);
                nfs_list_add_request(req, &data->pages);
                ClearPageError(req->wb_page);
                *pages++ = req->wb_page;
-               count += req->wb_bytes;
        }
        req = nfs_list_entry(data->pages.next);
 
@@ -917,44 +926,21 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
                struct nfs_page *req = nfs_list_entry(head->next);
                nfs_list_remove_request(req);
                nfs_redirty_request(req);
+               nfs_end_page_writeback(req->wb_page);
                nfs_clear_page_writeback(req);
        }
        return -ENOMEM;
 }
 
-static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how)
+static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
+                                 struct inode *inode, int ioflags)
 {
-       LIST_HEAD(one_request);
-       int (*flush_one)(struct inode *, struct list_head *, int);
-       struct nfs_page *req;
-       int wpages = NFS_SERVER(inode)->wpages;
        int wsize = NFS_SERVER(inode)->wsize;
-       int error;
 
-       flush_one = nfs_flush_one;
        if (wsize < PAGE_CACHE_SIZE)
-               flush_one = nfs_flush_multi;
-       /* For single writes, FLUSH_STABLE is more efficient */
-       if (npages <= wpages && npages == NFS_I(inode)->npages
-                       && nfs_list_entry(head->next)->wb_bytes <= wsize)
-               how |= FLUSH_STABLE;
-
-       do {
-               nfs_coalesce_requests(head, &one_request, wpages);
-               req = nfs_list_entry(one_request.next);
-               error = flush_one(inode, &one_request, how);
-               if (error < 0)
-                       goto out_err;
-       } while (!list_empty(head));
-       return 0;
-out_err:
-       while (!list_empty(head)) {
-               req = nfs_list_entry(head->next);
-               nfs_list_remove_request(req);
-               nfs_redirty_request(req);
-               nfs_clear_page_writeback(req);
-       }
-       return error;
+               nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
+       else
+               nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
 }
 
 /*
@@ -976,26 +962,31 @@ static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
                return;
 
        if (task->tk_status < 0) {
-               ClearPageUptodate(page);
-               SetPageError(page);
+               nfs_set_pageerror(page);
                req->wb_context->error = task->tk_status;
                dprintk(", error = %d\n", task->tk_status);
-       } else {
-#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-               if (data->verf.committed < NFS_FILE_SYNC) {
-                       if (!NFS_NEED_COMMIT(req)) {
-                               nfs_defer_commit(req);
-                               memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
-                               dprintk(" defer commit\n");
-                       } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
-                               nfs_defer_reschedule(req);
-                               dprintk(" server reboot detected\n");
-                       }
-               } else
-#endif
-                       dprintk(" OK\n");
+               goto out;
        }
 
+       if (nfs_write_need_commit(data)) {
+               spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
+
+               spin_lock(req_lock);
+               if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
+                       /* Do nothing we need to resend the writes */
+               } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+                       memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
+                       dprintk(" defer commit\n");
+               } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
+                       set_bit(PG_NEED_RESCHED, &req->wb_flags);
+                       clear_bit(PG_NEED_COMMIT, &req->wb_flags);
+                       dprintk(" server reboot detected\n");
+               }
+               spin_unlock(req_lock);
+       } else
+               dprintk(" OK\n");
+
+out:
        if (atomic_dec_and_test(&req->wb_complete))
                nfs_writepage_release(req);
 }
@@ -1034,28 +1025,23 @@ static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
                        (long long)req_offset(req));
 
                if (task->tk_status < 0) {
-                       ClearPageUptodate(page);
-                       SetPageError(page);
+                       nfs_set_pageerror(page);
                        req->wb_context->error = task->tk_status;
-                       end_page_writeback(page);
-                       nfs_inode_remove_request(req);
                        dprintk(", error = %d\n", task->tk_status);
-                       goto next;
+                       goto remove_request;
                }
-               end_page_writeback(page);
 
-#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
-               if (data->args.stable != NFS_UNSTABLE || data->verf.committed == NFS_FILE_SYNC) {
-                       nfs_inode_remove_request(req);
-                       dprintk(" OK\n");
+               if (nfs_write_need_commit(data)) {
+                       memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
+                       nfs_mark_request_commit(req);
+                       nfs_end_page_writeback(page);
+                       dprintk(" marked for commit\n");
                        goto next;
                }
-               memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
-               nfs_mark_request_commit(req);
-               dprintk(" marked for commit\n");
-#else
+               dprintk(" OK\n");
+remove_request:
+               nfs_end_page_writeback(page);
                nfs_inode_remove_request(req);
-#endif
        next:
                nfs_clear_page_writeback(req);
        }
@@ -1243,6 +1229,7 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata)
        while (!list_empty(&data->pages)) {
                req = nfs_list_entry(data->pages.next);
                nfs_list_remove_request(req);
+               clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
                dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 
                dprintk("NFS: commit (%s/%Ld %d@%Ld)",
@@ -1277,31 +1264,7 @@ static const struct rpc_call_ops nfs_commit_ops = {
        .rpc_call_done = nfs_commit_done,
        .rpc_release = nfs_commit_release,
 };
-#else
-static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
-{
-       return 0;
-}
-#endif
-
-static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
-{
-       struct nfs_inode *nfsi = NFS_I(mapping->host);
-       LIST_HEAD(head);
-       long res;
 
-       spin_lock(&nfsi->req_lock);
-       res = nfs_scan_dirty(mapping, wbc, &head);
-       spin_unlock(&nfsi->req_lock);
-       if (res) {
-               int error = nfs_flush_list(mapping->host, &head, res, how);
-               if (error < 0)
-                       return error;
-       }
-       return res;
-}
-
-#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 int nfs_commit_inode(struct inode *inode, int how)
 {
        struct nfs_inode *nfsi = NFS_I(inode);
@@ -1318,13 +1281,18 @@ int nfs_commit_inode(struct inode *inode, int how)
        }
        return res;
 }
+#else
+static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
+{
+       return 0;
+}
 #endif
 
 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;
+       pgoff_t idx_start, idx_end;
        unsigned int npages = 0;
        LIST_HEAD(head);
        int nocommit = how & FLUSH_NOCOMMIT;
@@ -1337,41 +1305,24 @@ long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_contr
                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;
+                       pgoff_t l_npages = 1 + idx_end - idx_start;
                        npages = l_npages;
                        if (sizeof(npages) != sizeof(l_npages) &&
-                                       (unsigned long)npages != l_npages)
+                                       (pgoff_t)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(mapping, wbc, &head);
-               if (pages != 0) {
-                       spin_unlock(&nfsi->req_lock);
-                       if (how & FLUSH_INVALIDATE) {
-                               nfs_cancel_dirty_list(&head);
-                               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 (wbc->pages_skipped != 0)
-                               continue;
+               if (pages == 0)
                        break;
-               }
                if (how & FLUSH_INVALIDATE) {
                        spin_unlock(&nfsi->req_lock);
                        nfs_cancel_commit_list(&head);
@@ -1403,7 +1354,7 @@ int nfs_wb_all(struct inode *inode)
        };
        int ret;
 
-       ret = generic_writepages(mapping, &wbc);
+       ret = nfs_writepages(mapping, &wbc);
        if (ret < 0)
                goto out;
        ret = nfs_sync_mapping_wait(mapping, &wbc, 0);
@@ -1426,11 +1377,9 @@ int nfs_sync_mapping_range(struct address_space *mapping, loff_t range_start, lo
        };
        int ret;
 
-       if (!(how & FLUSH_NOWRITEPAGE)) {
-               ret = generic_writepages(mapping, &wbc);
-               if (ret < 0)
-                       goto out;
-       }
+       ret = nfs_writepages(mapping, &wbc);
+       if (ret < 0)
+               goto out;
        ret = nfs_sync_mapping_wait(mapping, &wbc, how);
        if (ret >= 0)
                return 0;
@@ -1453,7 +1402,7 @@ int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
        int ret;
 
        BUG_ON(!PageLocked(page));
-       if (!(how & FLUSH_NOWRITEPAGE) && clear_page_dirty_for_io(page)) {
+       if (clear_page_dirty_for_io(page)) {
                ret = nfs_writepage_locked(page, &wbc);
                if (ret < 0)
                        goto out;
@@ -1478,15 +1427,32 @@ int nfs_wb_page(struct inode *inode, struct page* page)
 
 int nfs_set_page_dirty(struct page *page)
 {
+       struct address_space *mapping = page->mapping;
+       struct inode *inode;
+       spinlock_t *req_lock;
        struct nfs_page *req;
+       int ret;
 
-       req = nfs_page_find_request(page);
+       if (!mapping)
+               goto out_raced;
+       inode = mapping->host;
+       if (!inode)
+               goto out_raced;
+       req_lock = &NFS_I(inode)->req_lock;
+       spin_lock(req_lock);
+       req = nfs_page_find_request_locked(page);
        if (req != NULL) {
                /* Mark any existing write requests for flushing */
-               set_bit(PG_NEED_FLUSH, &req->wb_flags);
+               ret = !test_and_set_bit(PG_NEED_FLUSH, &req->wb_flags);
+               spin_unlock(req_lock);
                nfs_release_request(req);
+               return ret;
        }
-       return __set_page_dirty_nobuffers(page);
+       ret = __set_page_dirty_nobuffers(page);
+       spin_unlock(req_lock);
+       return ret;
+out_raced:
+       return !TestSetPageDirty(page);
 }
 
 
@@ -1509,6 +1475,26 @@ int __init nfs_init_writepagecache(void)
        if (nfs_commit_mempool == NULL)
                return -ENOMEM;
 
+       /*
+        * 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;
 }