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;