From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [Regression] Commit 02c24a82187d5a628c68edfe71ae60dc135cd178 breaks s2disk Date: Tue, 2 Aug 2011 02:17:48 +0200 Message-ID: <201108020217.48952.rjw@sisk.pl> References: <201108020147.01136.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <201108020147.01136.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Josef Bacik Cc: Jan Kara , Linux PM mailing list , Linus Torvalds , LKML , Al Viro List-Id: linux-pm@vger.kernel.org On Tuesday, August 02, 2011, Rafael J. Wysocki wrote: > Hi, > > Unfortunately s2disk (which is a user space tool for saving hibernate images) > doesn't work any more after your commit 02c24a82187d5a628c68edfe71ae60dc135cd178 > (fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers). > The symptom is that the s2disk's resume counterpart cannot find the image in > the device even though s2disk considers it as successfully saved. > > What happens is that s2disk opens a block device (disk partition to be precise) > directly and writes to it eventually calling fsync(). My interpretation of the > failure is that before commit 02c24a82187d5a628c68ed, when s2disk called fsync() > the VFS layer would run filemap_write_and_wait_range() that in turn would cause > the data to go to the disk, but after that commit this doesn't happen any more. > > If I'm right, then not only s2disk, but any process writing directly to a block > device will have a problem with fsync(). Well, I'm not sure if the patch below is the right fix, but it evidently makes s2disk work for me again. Thanks, Rafael --- fs/block_dev.c | 4 ++++ 1 file changed, 4 insertions(+) Index: linux-2.6/fs/block_dev.c =================================================================== --- linux-2.6.orig/fs/block_dev.c +++ linux-2.6/fs/block_dev.c @@ -387,6 +387,10 @@ int blkdev_fsync(struct file *filp, loff struct inode *bd_inode = filp->f_mapping->host; struct block_device *bdev = I_BDEV(bd_inode); int error; + + error = filemap_write_and_wait_range(filp->f_mapping, start, end); + if (error) + return error; /* * There is no need to serialise calls to blkdev_issue_flush with