Messages in this thread | | | Subject | Re: [Ext2-devel] [PATCH] fix ext3 mounts at 16T | From | sho@tnes ... | Date | Fri, 18 Aug 2006 18:15:16 +0900 |
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Hi,
>I figure before we get too fired up about 48 bits and ext4 let's fix 32 bits on ext3 :) > >I need to do some actual IO testing now, but this gets things mounting for a 16T ext3 >filesystem. >(patched up e2fsprogs is needed too, I'll send that off the kernel list) > >This patch fixes these issues in the kernel: > > o sbi->s_groups_count overflows in ext3_fill_super() > > sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) - > le32_to_cpu(es->s_first_data_block) + > EXT3_BLOCKS_PER_GROUP(sb) - 1) / > EXT3_BLOCKS_PER_GROUP(sb); > > at 16T, s_blocks_count is already maxed out; adding EXT3_BLOCKS_PER_GROUP(sb) overflows it and > groups_count comes out to 0. Not really what we want, and causes a failed mount. > > Feel free to check my math (actually, please do!), but changing it this way should work & > avoid the overflow: > > (A + B - 1)/B changed to: ((A - 1)/B) + 1 > > o ext3_check_descriptors() overflows range checks
I had done the same work for both ext3 and ext2, and sent the patches to ext2-devel three months ago. If you need, you can get them from the following URL.
The introduction for my patch set: http://marc.theaimsgroup.com/?l=ext2-devel&m=114856080926308&w=2
The patch which fixes overflow problem on ext3: http://marc.theaimsgroup.com/?l=ext2-devel&m=114856129220863&w=2
The patch which fixes overflow problem on ext2: http://marc.theaimsgroup.com/?l=ext2-devel&m=114856135120693&w=2
I have reviewed your patch and found other place which might cause overflow as below. If group_first_block is the first block of the last group, overflow will occur. This has already been fixed in my patch.
o ext3_try_to_allocate_with_rsv() in fs/ext3/balloc.c if ((my_rsv->rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb)) || (my_rsv->rsv_end < group_first_block)) BUG();
Cheers, Takashi - 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/
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