linux-kernel - [PATCH] fs: Do not check for valid page->mapping in page_cache_pipe_buf

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Message-Id: <1464233085-19165-1-git-send-email-adas@redhat.com>
Date:	Wed, 25 May 2016 22:24:45 -0500
From:	Abhi Das <adas@...hat.com>
To:	cluster-devel@...hat.com, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Cc:	Abhi Das <adas@...hat.com>, Miklos Szeredi <mszeredi@...hat.com>,
	Jens Axboe <axboe@...com>, Al Viro <viro@...iv.linux.org.uk>
Subject: [PATCH] fs: Do not check for valid page->mapping in page_cache_pipe_buf_confirm

If the page is truncated after being spliced into the pipe, it's
probably not invalid.

For filesystems that invalidate pages, we used to return -ENODATA
even though the data is there, it's just possibly different from
what was spliced into the pipe. We shouldn't have to throw away
the buffer or return error in this case.

Signed-off-by: Abhi Das <adas@...hat.com>
CC: Miklos Szeredi <mszeredi@...hat.com>
CC: Jens Axboe <axboe@...com>
CC: Al Viro <viro@...iv.linux.org.uk>
---
 fs/splice.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index dd9bf7e..b9899b99 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -106,15 +106,6 @@ static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
 		lock_page(page);
 
 		/*
-		 * Page got truncated/unhashed. This will cause a 0-byte
-		 * splice, if this is the first page.
-		 */
-		if (!page->mapping) {
-			err = -ENODATA;
-			goto error;
-		}
-
-		/*
 		 * Uh oh, read-error from disk.
 		 */
 		if (!PageUptodate(page)) {
-- 
2.4.3