From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: [patch v3] fix truncate inode time modification breakage Date: Thu, 3 Jun 2010 22:01:46 +1000 Message-ID: <20100603120146.GK6822@laptop> References: <20100601133923.GT9453@laptop> <20100601134801.GA11061@lst.de> <20100601135655.GU9453@laptop> <20100602195538.GG6152@laptop> <20100603091434.GA6822@laptop> <20100603100724.GE6822@laptop> <20100603110914.GA14006@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Miklos Szeredi , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, Hugh Dickins To: Al Viro , Christoph Hellwig Return-path: Received: from cantor2.suse.de ([195.135.220.15]:37254 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750960Ab0FCMCB (ORCPT ); Thu, 3 Jun 2010 08:02:01 -0400 Content-Disposition: inline In-Reply-To: <20100603110914.GA14006@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: I think this should be the best way to fix 2.6.35. I'll look at what it takes to completely direct truncate time/mode changes from the vfs probably on top of Christophs latest truncate patchsets. -- mtime and ctime should be changed only if the file size has actually changed. Patches changing ext2 and tmpfs from vmtruncate to new truncate sequence has caused regressions where they always update timestamps. There is some strange cases in POSIX where truncate(2) must not update times unless the size has acutally changed, see 6e656be89. This area is all still rather buggy in different ways in a lot of filesystems and needs a cleanup and audit (ideally the vfs will provide a simple attribute or call to direct all filesystems exactly which attributes to change). But coming up with the best solution will take a while and is not appropriate for rc anyway. So fix recent regression for now. Signed-off-by: Nick Piggin --- fs/ext2/inode.c | 2 +- mm/shmem.c | 5 +++-- 2 files changed, 4 insertions(+), 3 deletions(-) Index: linux-2.6/mm/shmem.c =================================================================== --- linux-2.6.orig/mm/shmem.c +++ linux-2.6/mm/shmem.c @@ -764,10 +764,11 @@ done2: static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; + loff_t newsize = attr->ia_size; int error; - if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { - loff_t newsize = attr->ia_size; + if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE) + && newsize != inode->i_size) { struct page *page = NULL; if (newsize < inode->i_size) { Index: linux-2.6/fs/ext2/inode.c =================================================================== --- linux-2.6.orig/fs/ext2/inode.c +++ linux-2.6/fs/ext2/inode.c @@ -1552,7 +1552,7 @@ int ext2_setattr(struct dentry *dentry, if (error) return error; } - if (iattr->ia_valid & ATTR_SIZE) { + if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) { error = ext2_setsize(inode, iattr->ia_size); if (error) return error;