From mboxrd@z Thu Jan 1 00:00:00 1970 From: Allison Henderson Subject: Re: [PATCH 4/6 v7] ext4: Lock i_mutex for punch hole Date: Wed, 31 Aug 2011 11:49:08 -0700 Message-ID: <4E5E8224.3040607@linux.vnet.ibm.com> References: <1314750513-10045-1-git-send-email-achender@linux.vnet.ibm.com> <1314750513-10045-5-git-send-email-achender@linux.vnet.ibm.com> <7607E9C9-650E-4C7F-B5EA-1DD76E564C05@dilger.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Andreas Dilger Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:33539 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751288Ab1HaStQ (ORCPT ); Wed, 31 Aug 2011 14:49:16 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e4.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p7VIPrK5020211 for ; Wed, 31 Aug 2011 14:25:53 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p7VInF1q131478 for ; Wed, 31 Aug 2011 14:49:15 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p7VInDha029079 for ; Wed, 31 Aug 2011 15:49:14 -0300 In-Reply-To: <7607E9C9-650E-4C7F-B5EA-1DD76E564C05@dilger.ca> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 08/30/2011 05:31 PM, Andreas Dilger wrote: > On 2011-08-30, at 6:28 PM, Allison Henderson wrote: >> This patch modifies the fallocate routine to lock i_mutex during >> the punch hole operation. >> >> Yongqiang noticed that the vfs layer locks i_mutex for truncate, >> but not fallocate, so the fallocate routine will need to take >> care of locking i_mutex. Otherwise a page may be mapped after >> punch hole has released the pages, but before i_data_sem is >> locked to release the blocks in the extent tree. > > If the VFS is locking i_mutex for truncate, shouldn't the locking for > fallocate() also be done in the VFS? Alrighty, I will do some poking around with this idea first. I dont know if other files systems are already locking i_mutex during fallocate, and it may be the case that not all filesystems need i_mutex locked for fallocate. So I'll do a little research first, but I will post back with what I find. Thx! Allison Henderson > >> Signed-off-by: Allison Henderson >> --- >> :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c >> fs/ext4/extents.c | 10 +++++++--- >> 1 files changed, 7 insertions(+), 3 deletions(-) >> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >> index 9124cd2..007fb08 100644 >> --- a/fs/ext4/extents.c >> +++ b/fs/ext4/extents.c >> @@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >> if (mode& ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) >> return -EOPNOTSUPP; >> >> - if (mode& FALLOC_FL_PUNCH_HOLE) >> - return ext4_punch_hole(file, offset, len); >> + mutex_lock(&inode->i_mutex); >> + >> + if (mode& FALLOC_FL_PUNCH_HOLE) { >> + ret = ext4_punch_hole(file, offset, len); >> + mutex_unlock(&inode->i_mutex); >> + return ret; >> + } >> >> trace_ext4_fallocate_enter(inode, offset, len, mode); >> map.m_lblk = offset>> blkbits; >> @@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >> * credits to insert 1 extent into extent tree >> */ >> credits = ext4_chunk_trans_blocks(inode, max_blocks); >> - mutex_lock(&inode->i_mutex); >> ret = inode_newsize_ok(inode, (len + offset)); >> if (ret) { >> mutex_unlock(&inode->i_mutex); >> -- >> 1.7.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Cheers, Andreas > > > > >