Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756806AbYFXD2t (ORCPT ); Mon, 23 Jun 2008 23:28:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753014AbYFXD2h (ORCPT ); Mon, 23 Jun 2008 23:28:37 -0400 Received: from E23SMTP04.au.ibm.com ([202.81.18.173]:56907 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbYFXD2g (ORCPT ); Mon, 23 Jun 2008 23:28:36 -0400 Date: Tue, 24 Jun 2008 08:58:07 +0530 From: "Aneesh Kumar K.V" To: Mingming Cc: Holger Kiehl , Theodore Tso , Eric Sandeen , Jan Kara , Solofo.Ramangalahy@bull.net, Nick Dokos , linux-ext4@vger.kernel.org, linux-kernel Subject: Re: Performance of ext4 Message-ID: <20080624032807.GC10469@skywalker> References: <20080619155645.GA8582@mit.edu> <485A8C2D.1090806@redhat.com> <20080619174211.GB9119@mit.edu> <20080620085922.GH9119@mit.edu> <20080623174508.GA7216@skywalker> <1214267492.27507.285.camel@BVR-FS.beaverton.ibm.com> <20080624030721.GB10469@skywalker> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080624030721.GB10469@skywalker> 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: 5060 Lines: 161 On Tue, Jun 24, 2008 at 08:37:21AM +0530, Aneesh Kumar K.V wrote: > On Mon, Jun 23, 2008 at 05:31:32PM -0700, Mingming wrote: > > > > On Mon, 2008-06-23 at 23:15 +0530, Aneesh Kumar K.V wrote: > > > > > I found one place where we fail to update i_disksize. Can you try this > > > patch ? > > > > > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > > > index 33f940b..9fa737f 100644 > > > --- a/fs/ext4/inode.c > > > +++ b/fs/ext4/inode.c > > > @@ -1620,7 +1620,10 @@ static int ext4_da_writepage(struct page *page, > > > loff_t size; > > > unsigned long len; > > > handle_t *handle = NULL; > > > + ext4_lblk_t block; > > > + loff_t disksize; > > > struct buffer_head *page_bufs; > > > + struct buffer_head *bh, *head; > > > struct inode *inode = page->mapping->host; > > > > > > handle = ext4_journal_current_handle(); > > > @@ -1662,6 +1665,38 @@ static int ext4_da_writepage(struct page *page, > > > else > > > ret = block_write_full_page(page, ext4_da_get_block_write, wbc); > > > > > > + if (ret) > > > + return ret; > > > + /* > > > + * When called via shrink_page_list and if we don't have any unmapped > > > + * buffer_head we still could have written some new content in an > > > + * already mapped buffer. That means we need to extent i_disksize here > > > + */ > > > > In this case(when extend the file without need block allocation), > > wouldn't make sense to update the i_disksize at write_end() time? So > > that the window of i_size different from i_disksize could be much > > smaller in this case. > > > > > > Something like below? (untested) > > In this case you will have to start a transaction in write_begin . With > the below code transaction is started inside page_lock. Also I don't > think we need needed_blocks credit just 1 should be enough because we > are not doing any block allocation here. We just need to update the > inode block. > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 33f940b..0ccf7b9 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1770,6 +1770,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, struct page *page; pgoff_t index; unsigned from, to; + handle_t *handle; struct inode *inode = mapping->host; index = pos >> PAGE_CACHE_SHIFT; @@ -1777,6 +1778,17 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, to = from + len; retry: + /* + * If we are writing towards the end of an already mapped + * buffer_head, we don't do any block allocation. But we + * need to update i_disksize. + */ + handle = ext4_journal_start(inode, 1); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + page = __grab_cache_page(mapping, index); if (!page) return -ENOMEM; @@ -1786,15 +1798,65 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, ext4_da_get_block_prep); if (ret < 0) { unlock_page(page); + ext4_journal_stop(handle); page_cache_release(page); } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; +out: return ret; } +static int ext4_da_write_end(struct file *file, + struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + handle_t *handle = ext4_journal_current_handle(); + struct inode *inode = mapping->host; + unsigned from, to; + int ret = 0, ret2; + + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + + if (ret == 0) { + /* + * generic_write_end() will run mark_inode_dirty() if i_size + * changes. So let's piggyback the i_disksize mark_inode_dirty + * into that. + */ + loff_t new_i_size; + + new_i_size = pos + copied; + if (new_i_size > EXT4_I(inode)->i_disksize) + if (!walk_page_buffers(NULL, page_buffers(page), + 0, len, NULL, + ext4_bh_unmapped_or_delay)) { + /* + * Updating i_disksize when extending file without + * need block allocation + */ + if (ext4_should_order_data(inode)) + ret = ext4_jbd2_file_inode(handle, inode); + + EXT4_I(inode)->i_disksize = new_i_size; + } + ret2 = generic_write_end(file, mapping, pos, + len, copied, page, fsdata); + copied = ret2; + if (ret2 < 0) + ret = ret2; + } + ret2 = ext4_journal_stop(handle); + if (!ret) + ret = ret2; + + return ret ? ret : copied; +} + static void ext4_da_invalidatepage(struct page *page, unsigned long offset) { /* @@ -2250,7 +2312,7 @@ static int ext4_journalled_set_page_dirty(struct page *page) .writepages = ext4_da_writepages, .sync_page = block_sync_page, .write_begin = ext4_da_write_begin, - .write_end = generic_write_end, + .write_end = ext4_da_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_da_invalidatepage, .releasepage = ext4_releasepage, -- 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/