NFS: Make nfs_updatepage() mark the page as dirty.

This will ensure that we can call set_page_writeback() from within
nfs_writepage(), which is always called with the page lock set.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 57 insertions, 17 deletions

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 0eca6a542106..130528d09a26 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -77,6 +77,7 @@
 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 int nfs_wait_on_requests(struct inode *, unsigned long, unsigned int);
 static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
@@ -245,29 +246,64 @@ 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);
+        ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
+        nfs_unlock_request(req);
+        return ret;
+}
+
+/*
  * Write an mmapped page to the server.
  */
 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 {
         struct nfs_open_context *ctx;
         struct inode *inode = page->mapping->host;
-        struct nfs_page *req;
         unsigned offset;
-        int err = 0;
+        int err;
 
         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 
-        req = nfs_page_find_request(page);
-        if (req != NULL) {
-                int flushme = test_bit(PG_NEED_FLUSH, &req->wb_flags);
-                nfs_release_request(req);
-                if (!flushme)
-                        goto out;
-                /* Ensure we've flushed out the invalid write */
-                nfs_wb_page_priority(inode, page, wb_priority(wbc) | FLUSH_STABLE | FLUSH_NOWRITEPAGE);
-        }
-
+        err = nfs_page_mark_flush(page);
+        if (err <= 0)
+                goto out;
+        err = 0;
         offset = nfs_page_length(page);
         if (!offset)
                 goto out;
@@ -279,7 +315,11 @@ static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc
         }
         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));
@@ -409,8 +449,7 @@ 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)
@@ -628,7 +667,6 @@ 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);
@@ -684,7 +722,7 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
                 if (req == NULL)
                         return 0;
                 do_flush = req->wb_page != page || req->wb_context != ctx
-                        || test_bit(PG_NEED_FLUSH, &req->wb_flags);
+                        || !nfs_dirty_request(req);
                 nfs_release_request(req);
                 if (!do_flush)
                         return 0;
@@ -723,6 +761,7 @@ int nfs_updatepage(struct file *file, struct page *page,
         }
 
         status = nfs_writepage_setup(ctx, page, offset, count);
+        __set_page_dirty_nobuffers(page);
 
         dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
                         status, (long long)i_size_read(inode));
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index d111be639140..2e555d49c9b7 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -31,6 +31,7 @@
 #define PG_NEED_COMMIT          1
 #define PG_NEED_RESCHED         2
 #define PG_NEED_FLUSH           3
+#define PG_FLUSHING             4
 
 struct nfs_inode;
 struct nfs_page {