Merge branch 'fixes' of git://git.linux-nfs.org/pub/linux/nfs-2.6

* 'fixes' of git://git.linux-nfs.org/pub/linux/nfs-2.6:
  NFS: Fix nfs_direct_dirty_pages()
  NFS: Fix handful of compiler warnings in direct.c
  NFS: Avoid a deadlock situation on write

3 files changed, 57 insertions, 22 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 345aa5c0f382..0c542ec92d5b 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -122,19 +122,25 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_
 	return -EINVAL;
 }
 
-static void nfs_direct_dirty_pages(struct page **pages, int npages)
+static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count)
 {
-	int i;
+	unsigned int npages;
+	unsigned int i;
+
+	if (count == 0)
+		return;
+	pages += (pgbase >> PAGE_SHIFT);
+	npages = (count + (pgbase & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	for (i = 0; i < npages; i++) {
 		struct page *page = pages[i];
 		if (!PageCompound(page))
-			set_page_dirty_lock(page);
+			set_page_dirty(page);
 	}
 }
 
-static void nfs_direct_release_pages(struct page **pages, int npages)
+static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
 {
-	int i;
+	unsigned int i;
 	for (i = 0; i < npages; i++)
 		page_cache_release(pages[i]);
 }
@@ -224,17 +230,18 @@ static void nfs_direct_read_result(struct rpc_task *task, void *calldata)
 	if (nfs_readpage_result(task, data) != 0)
 		return;
 
-	nfs_direct_dirty_pages(data->pagevec, data->npages);
-	nfs_direct_release_pages(data->pagevec, data->npages);
-
 	spin_lock(&dreq->lock);
-
-	if (likely(task->tk_status >= 0))
-		dreq->count += data->res.count;
-	else
+	if (unlikely(task->tk_status < 0)) {
 		dreq->error = task->tk_status;
-
-	spin_unlock(&dreq->lock);
+		spin_unlock(&dreq->lock);
+	} else {
+		dreq->count += data->res.count;
+		spin_unlock(&dreq->lock);
+		nfs_direct_dirty_pages(data->pagevec,
+				data->args.pgbase,
+				data->res.count);
+	}
+	nfs_direct_release_pages(data->pagevec, data->npages);
 
 	if (put_dreq(dreq))
 		nfs_direct_complete(dreq);
@@ -279,9 +286,12 @@ static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned lo
 		result = get_user_pages(current, current->mm, user_addr,
 					data->npages, 1, 0, data->pagevec, NULL);
 		up_read(&current->mm->mmap_sem);
-		if (unlikely(result < data->npages)) {
-			if (result > 0)
-				nfs_direct_release_pages(data->pagevec, result);
+		if (result < 0) {
+			nfs_readdata_release(data);
+			break;
+		}
+		if ((unsigned)result < data->npages) {
+			nfs_direct_release_pages(data->pagevec, result);
 			nfs_readdata_release(data);
 			break;
 		}
@@ -610,9 +620,12 @@ static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned l
 		result = get_user_pages(current, current->mm, user_addr,
 					data->npages, 0, 0, data->pagevec, NULL);
 		up_read(&current->mm->mmap_sem);
-		if (unlikely(result < data->npages)) {
-			if (result > 0)
-				nfs_direct_release_pages(data->pagevec, result);
+		if (result < 0) {
+			nfs_writedata_release(data);
+			break;
+		}
+		if ((unsigned)result < data->npages) {
+			nfs_direct_release_pages(data->pagevec, result);
 			nfs_writedata_release(data);
 			break;
 		}
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index cbdd1c6aaa94..c5bb51a29e80 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -355,6 +355,26 @@ void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
 	nfs_pageio_doio(desc);
 }
 
+/**
+ * nfs_pageio_cond_complete - Conditional I/O completion
+ * @desc: pointer to io descriptor
+ * @index: page index
+ *
+ * It is important to ensure that processes don't try to take locks
+ * on non-contiguous ranges of pages as that might deadlock. This
+ * function should be called before attempting to wait on a locked
+ * nfs_page. It will complete the I/O if the page index 'index'
+ * is not contiguous with the existing list of pages in 'desc'.
+ */
+void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
+{
+	if (!list_empty(&desc->pg_list)) {
+		struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev);
+		if (index != prev->wb_index + 1)
+			nfs_pageio_doio(desc);
+	}
+}
+
 #define NFS_SCAN_MAXENTRIES 16
 /**
  * nfs_scan_list - Scan a list for matching requests
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index b084c03ce493..af344a158e01 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -273,8 +273,6 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 		 *	 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)
@@ -321,6 +319,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
 		pgio = &mypgio;
 	}
 
+	nfs_pageio_cond_complete(pgio, page->index);
+
 	err = nfs_page_async_flush(pgio, page);
 	if (err <= 0)
 		goto out;
@@ -329,6 +329,8 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
 	if (!offset)
 		goto out;
 
+	nfs_pageio_cond_complete(pgio, page->index);
+
 	ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
 	if (ctx == NULL) {
 		err = -EBADF;