1 files changed, 157 insertions, 165 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index f333848fd3be..3229e217c773 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -34,9 +34,6 @@
 /*
  * Local function declarations
  */
-static struct nfs_page * nfs_update_request(struct nfs_open_context*,
-                                            struct page *,
-                                            unsigned int, unsigned int);
 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
                                   struct inode *inode, int ioflags);
 static void nfs_redirty_request(struct nfs_page *req);
@@ -136,16 +133,21 @@ static struct nfs_page *nfs_page_find_request(struct page *page)
 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 {
         struct inode *inode = page->mapping->host;
-        loff_t end, i_size = i_size_read(inode);
-        pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
+        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_CACHE_SHIFT;
         if (i_size > 0 && page->index < end_index)
-                return;
+                goto out;
         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
         if (i_size >= end)
-                return;
-        nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
+                goto out;
         i_size_write(inode, end);
+        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 */
@@ -169,29 +171,6 @@ static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int
         SetPageUptodate(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;
-
-        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);
-        nfs_clear_page_tag_locked(req);
-        return 0;
-}
-
 static int wb_priority(struct writeback_control *wbc)
 {
         if (wbc->for_reclaim)
@@ -268,12 +247,9 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
                         return ret;
                 spin_lock(&inode->i_lock);
         }
-        if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
-                /* This request is marked for commit */
+        if (test_bit(PG_CLEAN, &req->wb_flags)) {
                 spin_unlock(&inode->i_lock);
-                nfs_clear_page_tag_locked(req);
-                nfs_pageio_complete(pgio);
-                return 0;
+                BUG();
         }
         if (nfs_set_page_writeback(page) != 0) {
                 spin_unlock(&inode->i_lock);
@@ -355,11 +331,19 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 /*
  * Insert a write request into an inode
  */
-static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
+static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 {
         struct nfs_inode *nfsi = NFS_I(inode);
         int error;
 
+        error = radix_tree_preload(GFP_NOFS);
+        if (error != 0)
+                goto out;
+
+        /* Lock the request! */
+        nfs_lock_request_dontget(req);
+
+        spin_lock(&inode->i_lock);
         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
         BUG_ON(error);
         if (!nfsi->npages) {
@@ -373,6 +357,10 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
         kref_get(&req->wb_kref);
         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
                                 NFS_PAGE_TAG_LOCKED);
+        spin_unlock(&inode->i_lock);
+        radix_tree_preload_end();
+out:
+        return error;
 }
 
 /*
@@ -405,19 +393,6 @@ nfs_mark_request_dirty(struct nfs_page *req)
         __set_page_dirty_nobuffers(req->wb_page);
 }
 
-/*
- * Check if a request is dirty
- */
-static inline int
-nfs_dirty_request(struct nfs_page *req)
-{
-        struct page *page = req->wb_page;
-
-        if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))
-                return 0;
-        return !PageWriteback(page);
-}
-
 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 /*
  * Add a request to the inode's commit list.
@@ -430,7 +405,7 @@ nfs_mark_request_commit(struct nfs_page *req)
 
         spin_lock(&inode->i_lock);
         nfsi->ncommit++;
-        set_bit(PG_NEED_COMMIT, &(req)->wb_flags);
+        set_bit(PG_CLEAN, &(req)->wb_flags);
         radix_tree_tag_set(&nfsi->nfs_page_tree,
                         req->wb_index,
                         NFS_PAGE_TAG_COMMIT);
@@ -440,6 +415,19 @@ nfs_mark_request_commit(struct nfs_page *req)
         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
 
+static int
+nfs_clear_request_commit(struct nfs_page *req)
+{
+        struct page *page = req->wb_page;
+
+        if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
+                dec_zone_page_state(page, NR_UNSTABLE_NFS);
+                dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
+                return 1;
+        }
+        return 0;
+}
+
 static inline
 int nfs_write_need_commit(struct nfs_write_data *data)
 {
@@ -449,7 +437,7 @@ int nfs_write_need_commit(struct nfs_write_data *data)
 static inline
 int nfs_reschedule_unstable_write(struct nfs_page *req)
 {
-        if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+        if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
                 nfs_mark_request_commit(req);
                 return 1;
         }
@@ -465,6 +453,12 @@ nfs_mark_request_commit(struct nfs_page *req)
 {
 }
 
+static inline int
+nfs_clear_request_commit(struct nfs_page *req)
+{
+        return 0;
+}
+
 static inline
 int nfs_write_need_commit(struct nfs_write_data *data)
 {
@@ -522,11 +516,8 @@ 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);
-                dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
-                                BDI_RECLAIMABLE);
                 nfs_list_remove_request(req);
-                clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
+                nfs_clear_request_commit(req);
                 nfs_inode_remove_request(req);
                 nfs_unlock_request(req);
         }
@@ -564,110 +555,124 @@ static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pg
 #endif
 
 /*
- * 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
- * the calling process.
+ * Search for an existing write request, and attempt to update
+ * it to reflect a new dirty region on a given page.
  *
- * Note: Should always be called with the Page Lock held!
+ * If the attempt fails, then the existing request is flushed out
+ * to disk.
  */
-static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
-                struct page *page, unsigned int offset, unsigned int bytes)
+static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
+                struct page *page,
+                unsigned int offset,
+                unsigned int bytes)
 {
-        struct address_space *mapping = page->mapping;
-        struct inode *inode = mapping->host;
-        struct nfs_page         *req, *new = NULL;
-        pgoff_t         rqend, end;
+        struct nfs_page *req;
+        unsigned int rqend;
+        unsigned int end;
+        int error;
+
+        if (!PagePrivate(page))
+                return NULL;
 
         end = offset + bytes;
+        spin_lock(&inode->i_lock);
 
         for (;;) {
-                /* Loop over all inode entries and see if we find
-                 * A request for the page we wish to update
+                req = nfs_page_find_request_locked(page);
+                if (req == NULL)
+                        goto out_unlock;
+
+                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 (new) {
-                        if (radix_tree_preload(GFP_NOFS)) {
-                                nfs_release_request(new);
-                                return ERR_PTR(-ENOMEM);
-                        }
-                }
+                if (offset > rqend
+                    || end < req->wb_offset)
+                        goto out_flushme;
 
-                spin_lock(&inode->i_lock);
-                req = nfs_page_find_request_locked(page);
-                if (req) {
-                        if (!nfs_set_page_tag_locked(req)) {
-                                int error;
-
-                                spin_unlock(&inode->i_lock);
-                                error = nfs_wait_on_request(req);
-                                nfs_release_request(req);
-                                if (error < 0) {
-                                        if (new) {
-                                                radix_tree_preload_end();
-                                                nfs_release_request(new);
-                                        }
-                                        return ERR_PTR(error);
-                                }
-                                continue;
-                        }
-                        spin_unlock(&inode->i_lock);
-                        if (new) {
-                                radix_tree_preload_end();
-                                nfs_release_request(new);
-                        }
+                if (nfs_set_page_tag_locked(req))
                         break;
-                }
 
-                if (new) {
-                        nfs_lock_request_dontget(new);
-                        nfs_inode_add_request(inode, new);
-                        spin_unlock(&inode->i_lock);
-                        radix_tree_preload_end();
-                        req = new;
-                        goto zero_page;
-                }
+                /* The request is locked, so wait and then retry */
                 spin_unlock(&inode->i_lock);
-
-                new = nfs_create_request(ctx, inode, page, offset, bytes);
-                if (IS_ERR(new))
-                        return new;
+                error = nfs_wait_on_request(req);
+                nfs_release_request(req);
+                if (error != 0)
+                        goto out_err;
+                spin_lock(&inode->i_lock);
         }
 
-        /* We have a request for our page.
-         * If the creds don't match, or the
-         * page addresses don't match,
-         * tell the caller to wait on the conflicting
-         * request.
-         */
-        rqend = req->wb_offset + req->wb_bytes;
-        if (req->wb_context != ctx
-            || req->wb_page != page
-            || !nfs_dirty_request(req)
-            || offset > rqend || end < req->wb_offset) {
-                nfs_clear_page_tag_locked(req);
-                return ERR_PTR(-EBUSY);
-        }
+        if (nfs_clear_request_commit(req))
+                radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
+                                req->wb_index, NFS_PAGE_TAG_COMMIT);
 
         /* Okay, the request matches. Update the region */
         if (offset < req->wb_offset) {
                 req->wb_offset = offset;
                 req->wb_pgbase = offset;
-                req->wb_bytes = max(end, rqend) - req->wb_offset;
-                goto zero_page;
         }
-
         if (end > rqend)
                 req->wb_bytes = end - req->wb_offset;
-
+        else
+                req->wb_bytes = rqend - req->wb_offset;
+out_unlock:
+        spin_unlock(&inode->i_lock);
         return req;
-zero_page:
-        /* If this page might potentially be marked as up to date,
-         * then we need to zero any uninitalised data. */
-        if (req->wb_pgbase == 0 && req->wb_bytes != PAGE_CACHE_SIZE
-                        && !PageUptodate(req->wb_page))
-                zero_user_segment(req->wb_page, req->wb_bytes, PAGE_CACHE_SIZE);
+out_flushme:
+        spin_unlock(&inode->i_lock);
+        nfs_release_request(req);
+        error = nfs_wb_page(inode, page);
+out_err:
+        return ERR_PTR(error);
+}
+
+/*
+ * 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->mapping->host;
+        struct nfs_page *req;
+        int error;
+
+        req = nfs_try_to_update_request(inode, page, offset, bytes);
+        if (req != NULL)
+                goto out;
+        req = nfs_create_request(ctx, inode, page, offset, bytes);
+        if (IS_ERR(req))
+                goto out;
+        error = nfs_inode_add_request(inode, req);
+        if (error != 0) {
+                nfs_release_request(req);
+                req = ERR_PTR(error);
+        }
+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(page, req->wb_pgbase, req->wb_bytes);
+        nfs_clear_page_tag_locked(req);
+        return 0;
+}
+
 int nfs_flush_incompatible(struct file *file, struct page *page)
 {
         struct nfs_open_context *ctx = nfs_file_open_context(file);
@@ -685,8 +690,7 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
                 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);
+                do_flush = req->wb_page != page || req->wb_context != ctx;
                 nfs_release_request(req);
                 if (!do_flush)
                         return 0;
@@ -721,10 +725,10 @@ int nfs_updatepage(struct file *file, struct page *page,
 
         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 
-        dprintk("NFS:      nfs_updatepage(%s/%s %d@%Ld)\n",
+        dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
                 file->f_path.dentry->d_parent->d_name.name,
                 file->f_path.dentry->d_name.name, count,
-                (long long)(page_offset(page) +offset));
+                (long long)(page_offset(page) + offset));
 
         /* If we're not using byte range locks, and we know the page
          * is up to date, it may be more efficient to extend the write
@@ -744,7 +748,7 @@ int nfs_updatepage(struct file *file, struct page *page,
         else
                 __set_page_dirty_nobuffers(page);
 
-        dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
+        dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
                         status, (long long)i_size_read(inode));
         return status;
 }
@@ -752,12 +756,7 @@ int nfs_updatepage(struct file *file, struct page *page,
 static void nfs_writepage_release(struct nfs_page *req)
 {
 
-        if (PageError(req->wb_page)) {
-                nfs_end_page_writeback(req->wb_page);
-                nfs_inode_remove_request(req);
-        } else if (!nfs_reschedule_unstable_write(req)) {
-                /* Set the PG_uptodate flag */
-                nfs_mark_uptodate(req->wb_page, req->wb_pgbase, req->wb_bytes);
+        if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
                 nfs_end_page_writeback(req->wb_page);
                 nfs_inode_remove_request(req);
         } else
@@ -834,7 +833,7 @@ static int nfs_write_rpcsetup(struct nfs_page *req,
         NFS_PROTO(inode)->write_setup(data, &msg);
 
         dprintk("NFS: %5u initiated write call "
-                "(req %s/%Ld, %u bytes @ offset %Lu)\n",
+                "(req %s/%lld, %u bytes @ offset %llu)\n",
                 data->task.tk_pid,
                 inode->i_sb->s_id,
                 (long long)NFS_FILEID(inode),
@@ -978,13 +977,13 @@ static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
 {
         struct nfs_write_data   *data = calldata;
-        struct nfs_page         *req = data->req;
 
-        dprintk("NFS: write (%s/%Ld %d@%Ld)",
-                req->wb_context->path.dentry->d_inode->i_sb->s_id,
-                (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
-                req->wb_bytes,
-                (long long)req_offset(req));
+        dprintk("NFS: %5u write(%s/%lld %d@%lld)",
+                task->tk_pid,
+                data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
+                (long long)
+                  NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
+                data->req->wb_bytes, (long long)req_offset(data->req));
 
         nfs_writeback_done(task, data);
 }
@@ -1058,7 +1057,8 @@ static void nfs_writeback_release_full(void *calldata)
 
                 nfs_list_remove_request(req);
 
-                dprintk("NFS: write (%s/%Ld %d@%Ld)",
+                dprintk("NFS: %5u write (%s/%lld %d@%lld)",
+                        data->task.tk_pid,
                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
                         req->wb_bytes,
@@ -1078,8 +1078,6 @@ static void nfs_writeback_release_full(void *calldata)
                         dprintk(" marked for commit\n");
                         goto next;
                 }
-                /* Set the PG_uptodate flag? */
-                nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
                 dprintk(" OK\n");
 remove_request:
                 nfs_end_page_writeback(page);
@@ -1133,7 +1131,7 @@ int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
                 static unsigned long    complain;
 
                 if (time_before(complain, jiffies)) {
-                        dprintk("NFS: faulty NFS server %s:"
+                        dprintk("NFS:       faulty NFS server %s:"
                                 " (committed = %d) != (stable = %d)\n",
                                 NFS_SERVER(data->inode)->nfs_client->cl_hostname,
                                 resp->verf->committed, argp->stable);
@@ -1297,12 +1295,9 @@ static void nfs_commit_release(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);
-                dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
-                                BDI_RECLAIMABLE);
+                nfs_clear_request_commit(req);
 
-                dprintk("NFS: commit (%s/%Ld %d@%Ld)",
+                dprintk("NFS:       commit (%s/%lld %d@%lld)",
                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
                         req->wb_bytes,
@@ -1318,9 +1313,6 @@ static void nfs_commit_release(void *calldata)
                  * returned by the server against all stored verfs. */
                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
                         /* We have a match */
-                        /* Set the PG_uptodate flag */
-                        nfs_mark_uptodate(req->wb_page, req->wb_pgbase,
-                                        req->wb_bytes);
                         nfs_inode_remove_request(req);
                         dprintk(" OK\n");
                         goto next;
@@ -1479,7 +1471,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
                 req = nfs_page_find_request(page);
                 if (req == NULL)
                         goto out;
-                if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
+                if (test_bit(PG_CLEAN, &req->wb_flags)) {
                         nfs_release_request(req);
                         break;
                 }