[PATCH] fix ext3 mounts at 16T
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 ext3_check_descriptors() iterates over all block groups making sure that various bits are within the right block ranges... on the last pass through, it is checking the error case [item] >= block + EXT3_BLOCKS_PER_GROUP(sb) where "block" is the first block in the last block group. The last block in this group (and the last one that will fit in 32 bits) is block + EXT3_BLOCKS_PER_GROUP(sb)- 1. block + EXT3_BLOCKS_PER_GROUP(sb) wraps back around to 0. so, make things clearer with "first_block" and "last_block" where those are first and last, inclusive, and use <, > rather than <, >=. Finally, the last block group may be smaller than the rest, so account for this on the last pass through: last_block = sb->s_blocks_count - 1; (a similar patch could be done for ext2; does anyone in their right mind use ext2 at 16T? I'll send an ext2 patch doing the same thing if that's warranted) Signed-off-by: Eric Sandeen <esandeen@redhat.com> Cc: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -1174,7 +1174,8 @@ static int ext3_setup_super(struct super_block *sb, struct ext3_super_block *es,
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static int ext3_check_descriptors (struct super_block * sb)
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{
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struct ext3_sb_info *sbi = EXT3_SB(sb);
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ext3_fsblk_t block = le32_to_cpu(sbi->s_es->s_first_data_block);
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ext3_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
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ext3_fsblk_t last_block;
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struct ext3_group_desc * gdp = NULL;
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int desc_block = 0;
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int i;
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@ -1183,12 +1184,17 @@ static int ext3_check_descriptors (struct super_block * sb)
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for (i = 0; i < sbi->s_groups_count; i++)
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{
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if (i == sbi->s_groups_count - 1)
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last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
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else
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last_block = first_block +
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(EXT3_BLOCKS_PER_GROUP(sb) - 1);
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if ((i % EXT3_DESC_PER_BLOCK(sb)) == 0)
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gdp = (struct ext3_group_desc *)
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sbi->s_group_desc[desc_block++]->b_data;
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if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
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le32_to_cpu(gdp->bg_block_bitmap) >=
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block + EXT3_BLOCKS_PER_GROUP(sb))
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if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
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le32_to_cpu(gdp->bg_block_bitmap) > last_block)
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{
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ext3_error (sb, "ext3_check_descriptors",
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"Block bitmap for group %d"
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@ -1197,9 +1203,8 @@ static int ext3_check_descriptors (struct super_block * sb)
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le32_to_cpu(gdp->bg_block_bitmap));
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return 0;
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}
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if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
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le32_to_cpu(gdp->bg_inode_bitmap) >=
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block + EXT3_BLOCKS_PER_GROUP(sb))
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if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
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le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
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{
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ext3_error (sb, "ext3_check_descriptors",
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"Inode bitmap for group %d"
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@ -1208,9 +1213,9 @@ static int ext3_check_descriptors (struct super_block * sb)
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le32_to_cpu(gdp->bg_inode_bitmap));
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return 0;
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}
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if (le32_to_cpu(gdp->bg_inode_table) < block ||
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le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
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block + EXT3_BLOCKS_PER_GROUP(sb))
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if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
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le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
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last_block)
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{
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ext3_error (sb, "ext3_check_descriptors",
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"Inode table for group %d"
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@ -1219,7 +1224,7 @@ static int ext3_check_descriptors (struct super_block * sb)
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le32_to_cpu(gdp->bg_inode_table));
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return 0;
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}
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block += EXT3_BLOCKS_PER_GROUP(sb);
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first_block += EXT3_BLOCKS_PER_GROUP(sb);
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gdp++;
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}
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@ -1622,10 +1627,9 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
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if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
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goto cantfind_ext3;
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sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
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le32_to_cpu(es->s_first_data_block) +
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EXT3_BLOCKS_PER_GROUP(sb) - 1) /
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EXT3_BLOCKS_PER_GROUP(sb);
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sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
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le32_to_cpu(es->s_first_data_block) - 1)
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/ EXT3_BLOCKS_PER_GROUP(sb)) + 1;
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db_count = (sbi->s_groups_count + EXT3_DESC_PER_BLOCK(sb) - 1) /
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EXT3_DESC_PER_BLOCK(sb);
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sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
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