Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756262Ab1EDX5N (ORCPT ); Wed, 4 May 2011 19:57:13 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:57888 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756152Ab1EDX5L (ORCPT ); Wed, 4 May 2011 19:57:11 -0400 Date: Wed, 4 May 2011 16:57:06 -0700 From: "Darrick J. Wong" To: Chris Mason Cc: Christoph Hellwig , "Theodore Ts'o" , Jeff Layton , Jan Kara , Dave Chinner , Joel Becker , "Martin K. Petersen" , Jens Axboe , linux-kernel , linux-fsdevel , Mingming Cao , linux-scsi , Dave Hansen , linux-mm Subject: Re: [PATCH v3 0/3] data integrity: Stabilize pages during writeback for ext4 Message-ID: <20110504235706.GJ20579@tux1.beaverton.ibm.com> Reply-To: djwong@us.ibm.com References: <20110408203135.GH1110@tux1.beaverton.ibm.com> <20110411124229.47bc28f6@corrin.poochiereds.net> <1302543595-sup-4352@think> <1302569212.2580.13.camel@mingming-laptop> <20110412005719.GA23077@infradead.org> <1302742128.2586.274.camel@mingming-laptop> <20110422000226.GA22189@tux1.beaverton.ibm.com> <20110504173704.GE20579@tux1.beaverton.ibm.com> <20110504184644.GA23246@infradead.org> <1304536162-sup-3721@think> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1304536162-sup-3721@think> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3926 Lines: 116 On Wed, May 04, 2011 at 03:21:55PM -0400, Chris Mason wrote: > Excerpts from Christoph Hellwig's message of 2011-05-04 14:46:44 -0400: > > This seems to miss out on a lot of the generic functionality like > > write_cache_pages and block_page_mkwrite and just patch it into > > the ext4 copy & paste variants. Please make sure your patches also > > work for filesystem that use more of the generic functionality like > > xfs or ext2 (the latter one might be fun for the mmap case). > > Probably after the block_commit_write in block_page_mkwrite() > Another question is, do we want to introduce a wait_on_stable_page_writeback()? Something like this here? It fixes block_page_mkwrite users and sticks in a simple page_mkwrite for fses that don't provide one at all. From a quick wac run it seems to make xfs work. ext2 seems to have some issues with modifying a buffer_head's bh_data without locking the bh during the update, so I guess it needs some review. --D -- fs: Modify/provide generic writepage/page_mkwrite functions to wait for writeback Modify the generic writepage function, and add an empty page_mkwrite function, to wait for page writeback to finish before allowing writes. This is so that simple filesystems have stable pages during write operations. Signed-off-by: Darrick J. Wong --- fs/buffer.c | 1 + mm/filemap.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 0 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index a08bb8e..cf9a795 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2361,6 +2361,7 @@ block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, if (!ret) ret = block_commit_write(page, 0, end); + wait_on_page_writeback(page); if (unlikely(ret)) { unlock_page(page); if (ret == -ENOMEM) diff --git a/mm/filemap.c b/mm/filemap.c index c22675f..9cb4e51 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1713,8 +1713,18 @@ page_not_uptodate: } EXPORT_SYMBOL(filemap_fault); +static int empty_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + + lock_page(page); + wait_on_page_writeback(page); + return VM_FAULT_LOCKED; +} + const struct vm_operations_struct generic_file_vm_ops = { .fault = filemap_fault, + .page_mkwrite = empty_page_mkwrite, }; /* This is used for a general mmap of a disk file */ -- Here's the beginning of a patch against ext2 also. It fixes most of the checksum errors when metadata writes are in progress, though I suspect there are more spots that I haven't caught yet. -- ext2: Lock buffer_heads during metadata update ext2 does not protect buffer head that represent metadata against modifications during write operations. This is a problem if the memory buffer needs to be stable during writes; I think there are a few more spots in ext2 that need this treatment. :) Signed-off-by: Darrick J. Wong --- fs/ext2/inode.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 788e09a..5314b0b 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -1426,6 +1426,7 @@ static int __ext2_write_inode(struct inode *inode, int do_sync) if (IS_ERR(raw_inode)) return -EIO; + lock_buffer(bh); /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ if (ei->i_state & EXT2_STATE_NEW) @@ -1502,6 +1503,8 @@ static int __ext2_write_inode(struct inode *inode, int do_sync) } } else for (n = 0; n < EXT2_N_BLOCKS; n++) raw_inode->i_block[n] = ei->i_data[n]; + unlock_buffer(bh); + mark_buffer_dirty(bh); if (do_sync) { sync_dirty_buffer(bh); -- 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/