From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Thu, 23 Jan 2014 23:55:21 +0000 (-0800)
Subject: fs/pipe.c: skip file_update_time on frozen fs
X-Git-Tag: v3.14-rc1~108^2~51
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=7e775f46a125f894a1d71e96797c776dbec161f0;p=linux.git

fs/pipe.c: skip file_update_time on frozen fs

Pipe has no data associated with fs so it is not good idea to block
pipe_write() if FS is frozen, but we can not update file's time on such
filesystem.  Let's use same idea as we use in touch_time().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=65701

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/pipe.c b/fs/pipe.c
index 0e0752ef2715..78fd0d0788db 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -663,10 +663,11 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
 		wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 	}
-	if (ret > 0) {
+	if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) {
 		int err = file_update_time(filp);
 		if (err)
 			ret = err;
+		sb_end_write(file_inode(filp)->i_sb);
 	}
 	return ret;
 }