Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758439AbYAJCRk (ORCPT ); Wed, 9 Jan 2008 21:17:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757305AbYAJCRB (ORCPT ); Wed, 9 Jan 2008 21:17:01 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:37446 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756608AbYAJCQ7 (ORCPT ); Wed, 9 Jan 2008 21:16:59 -0500 From: Erez Zadok To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@ftp.linux.org.uk, hch@infradead.org, Erez Zadok Subject: [PATCH 2/4] Unionfs: mmap fixes Date: Wed, 9 Jan 2008 21:16:30 -0500 Message-Id: <1199931393738-git-send-email-ezk@cs.sunysb.edu> X-Mailer: git-send-email 1.5.2.2 X-MailKey: Erez_Zadok In-Reply-To: <1199931392670-git-send-email-ezk@cs.sunysb.edu> References: <1199931392670-git-send-email-ezk@cs.sunysb.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2577 Lines: 69 Ensure we have lower inodes in prepare/commit_write. Signed-off-by: Erez Zadok --- fs/unionfs/mmap.c | 26 +++++++++++++++++++++----- 1 files changed, 21 insertions(+), 5 deletions(-) diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c index a0e654b..ad770ac 100644 --- a/fs/unionfs/mmap.c +++ b/fs/unionfs/mmap.c @@ -224,13 +224,26 @@ out: static int unionfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) { + int err; + + unionfs_read_lock(file->f_path.dentry->d_sb, UNIONFS_SMUTEX_PARENT); /* - * Just copy lower inode attributes and return success. Not much - * else to do here. No need to lock either (lockdep won't like it). - * Let commit_write do all the hard work instead. + * This is the only place where we unconditionally copy the lower + * attribute times before calling unionfs_file_revalidate. The + * reason is that our ->write calls do_sync_write which in turn will + * call our ->prepare_write and then ->commit_write. Before our + * ->write is called, the lower mtimes are in sync, but by the time + * the VFS calls our ->commit_write, the lower mtimes have changed. + * Therefore, the only reasonable time for us to sync up from the + * changed lower mtimes, and avoid an invariant violation warning, + * is here, in ->prepare_write. */ unionfs_copy_attr_times(file->f_path.dentry->d_inode); - return 0; + err = unionfs_file_revalidate(file, true); + unionfs_check_file(file); + unionfs_read_unlock(file->f_path.dentry->d_sb); + + return err; } static int unionfs_commit_write(struct file *file, struct page *page, @@ -252,7 +265,6 @@ static int unionfs_commit_write(struct file *file, struct page *page, unionfs_check_file(file); inode = page->mapping->host; - lower_inode = unionfs_lower_inode(inode); if (UNIONFS_F(file) != NULL) lower_file = unionfs_lower_file(file); @@ -282,6 +294,10 @@ static int unionfs_commit_write(struct file *file, struct page *page, goto out; /* if vfs_write succeeded above, sync up our times/sizes */ + lower_inode = lower_file->f_path.dentry->d_inode; + if (!lower_inode) + lower_inode = unionfs_lower_inode(inode); + BUG_ON(!lower_inode); fsstack_copy_inode_size(inode, lower_inode); unionfs_copy_attr_times(inode); mark_inode_dirty_sync(inode); -- 1.5.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/