1 files changed, 36 insertions, 13 deletions

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index b7fc035a6943..49436fa7cd4f 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -986,6 +986,7 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
+	struct address_space *mapping = inode->i_mapping;
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder gh;
 	int rv;
@@ -1006,6 +1007,36 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 	if (rv != 1)
 		goto out; /* dio not valid, fall back to buffered i/o */
 
+	/*
+	 * Now since we are holding a deferred (CW) lock at this point, you
+	 * might be wondering why this is ever needed. There is a case however
+	 * where we've granted a deferred local lock against a cached exclusive
+	 * glock. That is ok provided all granted local locks are deferred, but
+	 * it also means that it is possible to encounter pages which are
+	 * cached and possibly also mapped. So here we check for that and sort
+	 * them out ahead of the dio. The glock state machine will take care of
+	 * everything else.
+	 *
+	 * If in fact the cached glock state (gl->gl_state) is deferred (CW) in
+	 * the first place, mapping->nr_pages will always be zero.
+	 */
+	if (mapping->nrpages) {
+		loff_t lstart = offset & (PAGE_CACHE_SIZE - 1);
+		loff_t len = iov_length(iov, nr_segs);
+		loff_t end = PAGE_ALIGN(offset + len) - 1;
+
+		rv = 0;
+		if (len == 0)
+			goto out;
+		if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
+			unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
+		rv = filemap_write_and_wait_range(mapping, lstart, end);
+		if (rv)
+			goto out;
+		if (rw == WRITE)
+			truncate_inode_pages_range(mapping, lstart, end);
+	}
+
 	rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 				  offset, nr_segs, gfs2_get_block_direct,
 				  NULL, NULL, 0);
@@ -1050,30 +1081,22 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 		bh = bh->b_this_page;
 	} while(bh != head);
 	spin_unlock(&sdp->sd_ail_lock);
-	gfs2_log_unlock(sdp);
 
 	head = bh = page_buffers(page);
 	do {
-		gfs2_log_lock(sdp);
 		bd = bh->b_private;
 		if (bd) {
 			gfs2_assert_warn(sdp, bd->bd_bh == bh);
-			if (!list_empty(&bd->bd_list)) {
-				if (!buffer_pinned(bh))
-					list_del_init(&bd->bd_list);
-				else
-					bd = NULL;
-			}
-			if (bd)
-				bd->bd_bh = NULL;
+			if (!list_empty(&bd->bd_list))
+				list_del_init(&bd->bd_list);
+			bd->bd_bh = NULL;
 			bh->b_private = NULL;
-		}
-		gfs2_log_unlock(sdp);
-		if (bd)
 			kmem_cache_free(gfs2_bufdata_cachep, bd);
+		}
 
 		bh = bh->b_this_page;
 	} while (bh != head);
+	gfs2_log_unlock(sdp);
 
 	return try_to_free_buffers(page);