linux-ext4 - Re: Patch on algorithm of place allocation for inode tables in mke2fs

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 16 Oct 2009 12:05:45 -0600
From:	Andreas Dilger <adilger@....com>
To:	Vyacheslav Dubeyko <Vyacheslav.Dubeyko@...onis.com>
Cc:	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: Patch on algorithm of place allocation for inode tables in mke2fs

On 16-Oct-09, at 08:45, Vyacheslav Dubeyko wrote:
> Let's try to make raw partition with 8 Gb size by fdisk and then to  
> format it (for example, mkfs.ext4 -b 4096 -L ext4_4K_8G /dev/sdb1).  
> If we have 2098482 block count on volume with 4 Kb block size and  
> flex block group size as 16 then we will have 65 groups on volume.  
> The last group (that has 1329 blocks) will be the first and sole  
> group in last flex group. Current mke2fs code makes such allocation  
> scheme in last group: Block bitmap at 2097152 (+0), Inode bitmap at  
> 2097168 (+16), Inode table at 8626 - 9130. The inode table of the  
> last group will be placed at the volume begin because of we can't  
> allocate sufficient block count for all inode tables in flex group.  
> I offer the patch for mke2fs utility:
>
> diff --git a/lib/ext2fs/alloc_tables.c b/lib/ext2fs/alloc_tables.c
> index 8547ad6..4639527 100644
> --- a/lib/ext2fs/alloc_tables.c
> +++ b/lib/ext2fs/alloc_tables.c
> @@ -181,10 +181,15 @@ errcode_t  
> ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
> 		blk_t prev_block = 0;
> 		if (group && fs->group_desc[group-1].bg_inode_table)
> 			prev_block = fs->group_desc[group-1].bg_inode_table;
> +		int requsted_size = 0;

This C++ style declaration needs to go at the beginning of the function.

> +		if ((group+1) == fs->group_desc_count &&
> +				(fs->group_desc_count % flexbg_size) == 1)
> +			requsted_size = fs->inode_blocks_per_group;
> +		else
> +			requsted_size = fs->inode_blocks_per_group * rem_grps;
> 		group_blk = flexbg_offset(fs, group, prev_block, bmap,
> 						 flexbg_size * 2,
> -						 fs->inode_blocks_per_group *
> -						 rem_grps,
> +						 requsted_size,
> 						 fs->inode_blocks_per_group);
> 		last_blk = ext2fs_group_last_block(fs, last_grp);
> 	}


I think the rest of this looks reasonable.

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