Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751413AbWHWGTK (ORCPT ); Wed, 23 Aug 2006 02:19:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751392AbWHWGTK (ORCPT ); Wed, 23 Aug 2006 02:19:10 -0400 Received: from mx1.mail.ru ([194.67.23.121]:51026 "EHLO mx1.mail.ru") by vger.kernel.org with ESMTP id S1751379AbWHWGTH (ORCPT ); Wed, 23 Aug 2006 02:19:07 -0400 Date: Wed, 23 Aug 2006 10:28:22 +0400 From: Evgeniy Dushistov To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Andrew Morton Subject: [PATCH 1/2]: ufs: write to hole in big file Message-ID: <20060823062822.GA8311@rain> Mail-Followup-To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3540 Lines: 122 Such scenario: open(O_TRUNC) lseek(1024 * 1024 * 80) write("A") lseek(1024 * 2) write("A") may cause access to invalid address. This happened because of "goal" is calculated in wrong way in block allocation path, as I see this problem exists also in 2.4. We use construction like this i_data[lastfrag], i_data array of pointers to direct blocks, indirect and so on, it has ceratain size ~20 elements, and lastfrag may have value for example 40000. Also this patch fixes related to handling such scenario issues, wrong zeroing metadata, in case of block(not fragment) allocation, and wrong goal calculation, when we allocate block Signed-off-by: Evgeniy Dushistov --- Index: linux-2.6.18-rc4-mm1/fs/ufs/inode.c =================================================================== --- linux-2.6.18-rc4-mm1.orig/fs/ufs/inode.c +++ linux-2.6.18-rc4-mm1/fs/ufs/inode.c @@ -169,18 +169,20 @@ static void ufs_clear_frag(struct inode static struct buffer_head * ufs_clear_frags(struct inode *inode, sector_t beg, - unsigned int n) + unsigned int n, sector_t want) { - struct buffer_head *res, *bh; + struct buffer_head *res = NULL, *bh; sector_t end = beg + n; - res = sb_getblk(inode->i_sb, beg); - ufs_clear_frag(inode, res); - for (++beg; beg < end; ++beg) { + for (; beg < end; ++beg) { bh = sb_getblk(inode->i_sb, beg); ufs_clear_frag(inode, bh); - brelse(bh); + if (want != beg) + brelse(bh); + else + res = bh; } + BUG_ON(!res); return res; } @@ -265,7 +267,9 @@ repeat: lastfrag = ufsi->i_lastfrag; } - goal = fs32_to_cpu(sb, ufsi->i_u1.i_data[lastblock]) + uspi->s_fpb; + tmp = fs32_to_cpu(sb, ufsi->i_u1.i_data[lastblock]); + if (tmp) + goal = tmp + uspi->s_fpb; tmp = ufs_new_fragments (inode, p, fragment - blockoff, goal, required + blockoff, err, locked_page); @@ -277,13 +281,15 @@ repeat: tmp = ufs_new_fragments(inode, p, fragment - (blockoff - lastblockoff), fs32_to_cpu(sb, *p), required + (blockoff - lastblockoff), err, locked_page); - } + } else /* (lastblock > block) */ { /* * We will allocate new block before last allocated block */ - else /* (lastblock > block) */ { - if (lastblock && (tmp = fs32_to_cpu(sb, ufsi->i_u1.i_data[lastblock-1]))) - goal = tmp + uspi->s_fpb; + if (block) { + tmp = fs32_to_cpu(sb, ufsi->i_u1.i_data[block-1]); + if (tmp) + goal = tmp + uspi->s_fpb; + } tmp = ufs_new_fragments(inode, p, fragment - blockoff, goal, uspi->s_fpb, err, locked_page); } @@ -296,7 +302,7 @@ repeat: } if (!phys) { - result = ufs_clear_frags(inode, tmp + blockoff, required); + result = ufs_clear_frags(inode, tmp, required, tmp + blockoff); } else { *phys = tmp + blockoff; result = NULL; @@ -383,7 +389,7 @@ repeat: } } - if (block && (tmp = fs32_to_cpu(sb, ((__fs32*)bh->b_data)[block-1]) + uspi->s_fpb)) + if (block && (tmp = fs32_to_cpu(sb, ((__fs32*)bh->b_data)[block-1]))) goal = tmp + uspi->s_fpb; else goal = bh->b_blocknr + uspi->s_fpb; @@ -397,7 +403,8 @@ repeat: if (!phys) { - result = ufs_clear_frags(inode, tmp + blockoff, uspi->s_fpb); + result = ufs_clear_frags(inode, tmp, uspi->s_fpb, + tmp + blockoff); } else { *phys = tmp + blockoff; *new = 1; -- /Evgeniy - 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/