[PATCH] Now that sync_filesystem() must be called from ->remount_fs() it needs to be EXPORT_SYMBOL() for kernel modules.

From: Anton Altaparmakov <aia21@cam.ac.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH] Now that sync_filesystem() must be called from ->remount_fs() it needs to be EXPORT_SYMBOL() for kernel modules.
Date: Thu, 21 Aug 2014 11:09:27 +0100 (BST)	[thread overview]
Message-ID: <Pine.LNX.4.64.1408211047230.11319@hermes-1.csi.cam.ac.uk> (raw)

This patch changes sync_filesystem() to be EXPORT_SYMBOL().

The reason this is needed is that starting with 3.15 kernel, due to 
Theodore Ts'o's commit 02b9984d640873b7b3809e63f81a0d7e13496886, "fs: push 
sync_filesystem() down to the file system's remount_fs()", all file 
systems that have dirty data to be written out need to call 
sync_filesystem() from their ->remount_fs() method when remounting 
read-only.

As this is now a generically required function rather than an internal 
only function it should be EXPORT_SYMBOL() so that all file systems can
call it.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
---

Hi Linus,

Can you please apply this patch for inclusion into 3.17?  Explanation is 
above.

Thanks a lot in advance!

PS. I hope Pine does not mess up the whitespace of the patch!

Best regards,

	Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK

--- linux/fs/sync.c	2014-08-21 10:30:26.000000000 +0100
+++ linux/fs/sync.c	2014-08-21 10:30:47.000000000 +0100
@@ -65,7 +65,7 @@ int sync_filesystem(struct super_block *
 		return ret;
 	return __sync_filesystem(sb, 1);
 }
-EXPORT_SYMBOL_GPL(sync_filesystem);
+EXPORT_SYMBOL(sync_filesystem);
 
 static void sync_inodes_one_sb(struct super_block *sb, void *arg)
 {
