From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934356Ab2AJXDL (ORCPT ); Tue, 10 Jan 2012 18:03:11 -0500 Received: from cantor2.suse.de ([195.135.220.15]:52695 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934342Ab2AJXDF (ORCPT ); Tue, 10 Jan 2012 18:03:05 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Jan 10 13:56:04 2012 Message-Id: <20120110215604.319826410@clark.kroah.org> User-Agent: quilt/0.50-25.1 Date: Tue, 10 Jan 2012 13:55:35 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jan Kara Subject: [32/49] udf: Fix deadlock when converting file from in-ICB one to normal one In-Reply-To: <20120110215609.GA22505@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit d2eb8c359309ec45d6bf5b147303ab8e13be86ea upstream. During BKL removal in 2.6.38, conversion of files from in-ICB format to normal format got broken. We call ->writepage with i_data_sem held but udf_get_block() also acquires i_data_sem thus creating A-A deadlock. We fix the problem by dropping i_data_sem before calling ->writepage() which is safe since i_mutex still protects us against any changes in the file. Also fix pagelock - i_data_sem lock inversion in udf_expand_file_adinicb() by dropping i_data_sem before calling find_or_create_page(). Reported-by: Matthias Matiak Tested-by: Matthias Matiak Reviewed-by: Namjae Jeon Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/udf/file.c | 6 +++--- fs/udf/inode.c | 21 ++++++++++++++++++--- 2 files changed, 21 insertions(+), 6 deletions(-) --- a/fs/udf/file.c +++ b/fs/udf/file.c @@ -125,7 +125,6 @@ static ssize_t udf_file_aio_write(struct err = udf_expand_file_adinicb(inode); if (err) { udf_debug("udf_expand_adinicb: err=%d\n", err); - up_write(&iinfo->i_data_sem); return err; } } else { @@ -133,9 +132,10 @@ static ssize_t udf_file_aio_write(struct iinfo->i_lenAlloc = pos + count; else iinfo->i_lenAlloc = inode->i_size; + up_write(&iinfo->i_data_sem); } - } - up_write(&iinfo->i_data_sem); + } else + up_write(&iinfo->i_data_sem); retval = generic_file_aio_write(iocb, iov, nr_segs, ppos); if (retval > 0) --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -151,6 +151,12 @@ const struct address_space_operations ud .bmap = udf_bmap, }; +/* + * Expand file stored in ICB to a normal one-block-file + * + * This function requires i_data_sem for writing and releases it. + * This function requires i_mutex held + */ int udf_expand_file_adinicb(struct inode *inode) { struct page *page; @@ -169,9 +175,15 @@ int udf_expand_file_adinicb(struct inode iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG; /* from now on we have normal address_space methods */ inode->i_data.a_ops = &udf_aops; + up_write(&iinfo->i_data_sem); mark_inode_dirty(inode); return 0; } + /* + * Release i_data_sem so that we can lock a page - page lock ranks + * above i_data_sem. i_mutex still protects us against file changes. + */ + up_write(&iinfo->i_data_sem); page = find_or_create_page(inode->i_mapping, 0, GFP_NOFS); if (!page) @@ -187,6 +199,7 @@ int udf_expand_file_adinicb(struct inode SetPageUptodate(page); kunmap(page); } + down_write(&iinfo->i_data_sem); memset(iinfo->i_ext.i_data + iinfo->i_lenEAttr, 0x00, iinfo->i_lenAlloc); iinfo->i_lenAlloc = 0; @@ -196,17 +209,20 @@ int udf_expand_file_adinicb(struct inode iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG; /* from now on we have normal address_space methods */ inode->i_data.a_ops = &udf_aops; + up_write(&iinfo->i_data_sem); err = inode->i_data.a_ops->writepage(page, &udf_wbc); if (err) { /* Restore everything back so that we don't lose data... */ lock_page(page); kaddr = kmap(page); + down_write(&iinfo->i_data_sem); memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size); kunmap(page); unlock_page(page); iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB; inode->i_data.a_ops = &udf_adinicb_aops; + up_write(&iinfo->i_data_sem); } page_cache_release(page); mark_inode_dirty(inode); @@ -1111,10 +1127,9 @@ int udf_setsize(struct inode *inode, lof if (bsize < (udf_file_entry_alloc_offset(inode) + newsize)) { err = udf_expand_file_adinicb(inode); - if (err) { - up_write(&iinfo->i_data_sem); + if (err) return err; - } + down_write(&iinfo->i_data_sem); } else iinfo->i_lenAlloc = newsize; }