Date: Thu, 22 Nov 2001 14:34:50 +0100 From: Miquel van Smoorenburg To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org Subject: [PATCH] block_dev.c: fsync() on close() considered harmful Message-ID: <20011122143450.A28020@cistron.nl> Reply-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i X-NCC-RegID: nl.cistron I'm running an INN usenet news server that uses raw partitions for storage. I.e. it opens /dev/sda7 etc. and mmap()s [which finally works in 2.4, hurray] Even though the server is keeping those devices open, when a utility program (sm) opens that file/device and closes() it the close() causes a fsync() on the device, something that is not wanted. I applied the following patch which fixes it for me, it prevents the sync-after-close if it was close() calling blkdev_put() and we're not the last one to call blkdev_put(). That means fsync() will still be done on unmounts or when the last user of the device closes it, but not otherwise. Is this correct or am I overlooking something? --- linux-2.4.15-pre8/fs/block_dev.c.orig Thu Oct 25 22:58:35 2001 +++ linux-2.4.15-pre8/fs/block_dev.c Wed Nov 21 13:32:16 2001 @@ -603,7 +603,7 @@ down(&bdev->bd_sem); lock_kernel(); - if (kind == BDEV_FILE) + if (kind == BDEV_FILE && bdev->bd_openers == 1) __block_fsync(bd_inode); else if (kind == BDEV_FS) fsync_no_super(rdev); Mike. -- "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former" -- Albert Einstein.