From: Subject: Patch "ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages" has been added to the 2.6.27-stable tree Date: Fri, 25 Jun 2010 16:32:18 -0700 Message-ID: <12775087381163@site> References: <4C00191B.3030702@jaysonking.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Cc: , To: aneesh.kumar@linux.vnet.ibm.com, david@fromorbit.com, dev@jaysonking.com, gregkh@suse.de, Kay.Diederichs@uni-konstanz.de, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, sta Return-path: Received: from kroah.org ([198.145.64.141]:33855 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756520Ab0FYXci (ORCPT ); Fri, 25 Jun 2010 19:32:38 -0400 In-Reply-To: <4C00191B.3030702@jaysonking.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages to the 2.6.27-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch and it can be found in the queue-2.6.27 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From dev@jaysonking.com Fri Jun 25 15:33:41 2010 From: Aneesh Kumar K.V Date: Fri, 28 May 2010 14:27:23 -0500 Subject: ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages To: Stable team , LKML , Greg Kroah-Hartman Cc: "Theodore Ts'o" , Dave Chinner , "Jayson R. King" , Kay Diederichs , Ext4 Developers List , "Aneesh Kumar K.V" Message-ID: <4C00191B.3030702@jaysonking.com> From: Aneesh Kumar K.V commit 2acf2c261b823d9d9ed954f348b97620297a36b5 upstream. With delayed allocation we lock the page in write_cache_pages() and try to build an in memory extent of contiguous blocks. This is needed so that we can get large contiguous blocks request. If range_cyclic mode is enabled, write_cache_pages() will loop back to the 0 index if no I/O has been done yet, and try to start writing from the beginning of the range. That causes an attempt to take the page lock of lower index page while holding the page lock of higher index page, which can cause a dead lock with another writeback thread. The solution is to implement the range_cyclic behavior in ext4_da_writepages() instead. http://bugzilla.kernel.org/show_bug.cgi?id=12579 Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" Signed-off-by: Jayson R. King Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2575,6 +2575,7 @@ static int ext4_da_writepages(struct add struct mpage_da_data mpd; struct inode *inode = mapping->host; long pages_written = 0, pages_skipped; + int range_cyclic, cycled = 1, io_done = 0; int needed_blocks, ret = 0, nr_to_writebump = 0; struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); @@ -2612,9 +2613,15 @@ static int ext4_da_writepages(struct add if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) range_whole = 1; - if (wbc->range_cyclic) + range_cyclic = wbc->range_cyclic; + if (wbc->range_cyclic) { index = mapping->writeback_index; - else + if (index) + cycled = 0; + wbc->range_start = index << PAGE_CACHE_SHIFT; + wbc->range_end = LLONG_MAX; + wbc->range_cyclic = 0; + } else index = wbc->range_start >> PAGE_CACHE_SHIFT; mpd.wbc = wbc; @@ -2622,6 +2629,7 @@ static int ext4_da_writepages(struct add pages_skipped = wbc->pages_skipped; +retry: while (!ret && wbc->nr_to_write > 0) { /* @@ -2676,6 +2684,7 @@ static int ext4_da_writepages(struct add pages_written += mpd.pages_written; wbc->pages_skipped = pages_skipped; ret = 0; + io_done = 1; } else if (wbc->nr_to_write) /* * There is no more writeout needed @@ -2684,6 +2693,13 @@ static int ext4_da_writepages(struct add */ break; } + if (!io_done && !cycled) { + cycled = 1; + index = 0; + wbc->range_start = index << PAGE_CACHE_SHIFT; + wbc->range_end = mapping->writeback_index - 1; + goto retry; + } if (pages_skipped != wbc->pages_skipped) printk(KERN_EMERG "This should not happen leaving %s " "with nr_to_write = %ld ret = %d\n", @@ -2691,6 +2707,7 @@ static int ext4_da_writepages(struct add /* Update index */ index += pages_written; + wbc->range_cyclic = range_cyclic; if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) /* * set the writeback_index so that range_cyclic Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch queue-2.6.27/ext4-use-our-own-write_cache_pages.patch queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch