lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <20080103191733.GJ3351@webber.adilger.int> Date: Thu, 3 Jan 2008 12:17:33 -0700 From: Andreas Dilger <adilger@....com> To: Eric Sandeen <sandeen@...hat.com> Cc: ext4 development <linux-ext4@...r.kernel.org>, Alex Tomas <alex@...sterfs.com> Subject: Re: [PATCH] UPDATED: types fixup for mballoc On Jan 02, 2008 14:01 -0600, Eric Sandeen wrote: > This patch: > > changes fe_len to an int, I don't think we need it to be a long, > looking at how it's used (should it be a grpblk_t?) Also change > anything assigned to return value of mb_find_extent, since it returns > fe_len. > > changes anything that does groupno * EXT4_BLOCKS_PER_GROUP > or pa->pa_pstart + <whatever> to an ext4_fsblk_t > > fixes up any related formats > > The change to ext4_mb_scan_aligned to avoid a 64-bit modulo > could use an extra look I think. > > @@ -1732,17 +1735,18 @@ static void ext4_mb_scan_aligned(struct > BUG_ON(sbi->s_stripe == 0); > > - /* find first stripe-aligned block */ > - i = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) > - + le32_to_cpu(sbi->s_es->s_first_data_block); > - i = ((i + sbi->s_stripe - 1) / sbi->s_stripe) * sbi->s_stripe; > - i = (i - le32_to_cpu(sbi->s_es->s_first_data_block)) > - % EXT4_BLOCKS_PER_GROUP(sb); > + /* find first stripe-aligned block in group */ > + a = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) > + + le32_to_cpu(sbi->s_es->s_first_data_block); > + a = (a + sbi->s_stripe - 1) & ~((ext4_fsblk_t)sbi->s_stripe - 1); > + a = a - le32_to_cpu(sbi->s_es->s_first_data_block); > + i = do_div(a, EXT4_BLOCKS_PER_GROUP(sb)); I don't think this is correct... This code should only be used if s_stripe is NOT a power-of-two value, otherwise we can just use the buddy maps to find aligned chunks. As a result I don't think that "& (s_stripe - 1)" change is equivalent to "/ s_stripe * s_stripe". > while (i < sb->s_blocksize * 8) { > if (!mb_test_bit(i, bitmap)) { Hrmmm, I thought this should be "while (i < EXT4_BLOCKS_PER_GROUP(sb))" and not "sb->s_blocksize * 8"? Did that fix get lost somewhere? There are a few other changes in the patch related to this fix: https://bugzilla.lustre.org/attachment.cgi?id=13275 Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists