X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fsplice.c;h=4eed2f6c8eeb812921a3a047d996da6cb77742f7;hb=16c70f8c1b54b61c3b951b6fb220df250fe09b32;hp=8fef6672b9b62dc46cfccc8f7352ea55a18d9736;hpb=4e76c8a9fa413ccc09d3f7f664183dcce3555d57;p=linux-2.6.git

diff --git a/fs/splice.c b/fs/splice.c
index 8fef6672b..4eed2f6c8 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -55,31 +55,43 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
 				     struct pipe_buffer *buf)
 {
 	struct page *page = buf->page;
-	struct address_space *mapping = page_mapping(page);
+	struct address_space *mapping;
 
 	lock_page(page);
 
-	WARN_ON(!PageUptodate(page));
+	mapping = page_mapping(page);
+	if (mapping) {
+		WARN_ON(!PageUptodate(page));
 
-	/*
-	 * At least for ext2 with nobh option, we need to wait on writeback
-	 * completing on this page, since we'll remove it from the pagecache.
-	 * Otherwise truncate wont wait on the page, allowing the disk
-	 * blocks to be reused by someone else before we actually wrote our
-	 * data to them. fs corruption ensues.
-	 */
-	wait_on_page_writeback(page);
+		/*
+		 * At least for ext2 with nobh option, we need to wait on
+		 * writeback completing on this page, since we'll remove it
+		 * from the pagecache.  Otherwise truncate wont wait on the
+		 * page, allowing the disk blocks to be reused by someone else
+		 * before we actually wrote our data to them. fs corruption
+		 * ensues.
+		 */
+		wait_on_page_writeback(page);
 
-	if (PagePrivate(page))
-		try_to_release_page(page, mapping_gfp_mask(mapping));
+		if (PagePrivate(page))
+			try_to_release_page(page, mapping_gfp_mask(mapping));
 
-	if (!remove_mapping(mapping, page)) {
-		unlock_page(page);
-		return 1;
+		/*
+		 * If we succeeded in removing the mapping, set LRU flag
+		 * and return good.
+		 */
+		if (remove_mapping(mapping, page)) {
+			buf->flags |= PIPE_BUF_FLAG_LRU;
+			return 0;
+		}
 	}
 
-	buf->flags |= PIPE_BUF_FLAG_LRU;
-	return 0;
+	/*
+	 * Raced with truncate or failed to remove page from current
+	 * address space, unlock and return failure.
+	 */
+	unlock_page(page);
+	return 1;
 }
 
 static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
@@ -595,7 +607,7 @@ find_page:
 			ret = -ENOMEM;
 			page = page_cache_alloc_cold(mapping);
 			if (unlikely(!page))
-				goto out_nomem;
+				goto out_ret;
 
 			/*
 			 * This will also lock the page
@@ -654,7 +666,7 @@ find_page:
 		if (sd->pos + this_len > isize)
 			vmtruncate(mapping->host, isize);
 
-		goto out;
+		goto out_ret;
 	}
 
 	if (buf->page != page) {
@@ -686,7 +698,7 @@ find_page:
 out:
 	page_cache_release(page);
 	unlock_page(page);
-out_nomem:
+out_ret:
 	return ret;
 }
 
@@ -1389,11 +1401,11 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 	 * could deadlock (one doing tee from A -> B, the other from B -> A).
 	 */
 	if (ipipe->inode < opipe->inode) {
-		mutex_lock(&ipipe->inode->i_mutex);
-		mutex_lock(&opipe->inode->i_mutex);
+		mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_CHILD);
 	} else {
-		mutex_lock(&opipe->inode->i_mutex);
-		mutex_lock(&ipipe->inode->i_mutex);
+		mutex_lock_nested(&opipe->inode->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&ipipe->inode->i_mutex, I_MUTEX_CHILD);
 	}
 
 	do {