From e703c206135acb458adb705ec44bcc5d2615b37d Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Fri, 2 Mar 2012 13:09:05 +0100 Subject: [PATCH] ext3: fix start and len arguments handling in ext3_trim_fs() The overflow might happen when passing blocknr into ext3_get_group_no_and_offset(), because it expects type ext3_fsblk_t which might be smaller than uint64_t. This will most likely happen when calling FITRIM with the default argument len = ULLONG_MAX. Fix this by using "end" variable instead of "start+len" as it is easier to get right and specifically check that the end is not beyond the end of the file system, so we are sure that the result of get_group_no_and_offset() will not overflow. Otherwise truncate it to the size of the file system. Signed-off-by: Lukas Czerner Cc: Jan Kara Signed-off-by: Jan Kara --- fs/ext3/balloc.c | 77 ++++++++++++++++++++++++------------------------ 1 file changed, 39 insertions(+), 38 deletions(-) diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index 954a7d355f59..1e036b79384c 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -1973,7 +1973,7 @@ static ext3_grpblk_t ext3_trim_all_free(struct super_block *sb, sbi = EXT3_SB(sb); /* Walk through the whole group */ - while (start < max) { + while (start <= max) { start = bitmap_search_next_usable_block(start, bitmap_bh, max); if (start < 0) break; @@ -1983,7 +1983,7 @@ static ext3_grpblk_t ext3_trim_all_free(struct super_block *sb, * Allocate contiguous free extents by setting bits in the * block bitmap */ - while (next < max + while (next <= max && claim_block(sb_bgl_lock(sbi, group), next, bitmap_bh)) { next++; @@ -2094,73 +2094,74 @@ err_out: */ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range) { - ext3_grpblk_t last_block, first_block, free_blocks; - unsigned long first_group, last_group; - unsigned long group, ngroups; + ext3_grpblk_t last_block, first_block; + unsigned long group, first_group, last_group; struct ext3_group_desc *gdp; struct ext3_super_block *es = EXT3_SB(sb)->s_es; - uint64_t start, len, minlen, trimmed; + uint64_t start, minlen, end, trimmed = 0; + ext3_fsblk_t first_data_blk = + le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block); ext3_fsblk_t max_blks = le32_to_cpu(es->s_blocks_count); int ret = 0; - start = (range->start >> sb->s_blocksize_bits) + - le32_to_cpu(es->s_first_data_block); - len = range->len >> sb->s_blocksize_bits; + start = range->start >> sb->s_blocksize_bits; + end = start + (range->len >> sb->s_blocksize_bits) - 1; minlen = range->minlen >> sb->s_blocksize_bits; - trimmed = 0; - if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb))) + if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)) || + unlikely(start >= max_blks)) return -EINVAL; - if (start >= max_blks) - return -EINVAL; - if (start + len > max_blks) - len = max_blks - start; + if (end >= max_blks) + end = max_blks - 1; + if (end <= first_data_blk) + goto out; + if (start < first_data_blk) + start = first_data_blk; - ngroups = EXT3_SB(sb)->s_groups_count; smp_rmb(); /* Determine first and last group to examine based on start and len */ ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) start, &first_group, &first_block); - ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) (start + len), + ext3_get_group_no_and_offset(sb, (ext3_fsblk_t) end, &last_group, &last_block); - last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group; - last_block = EXT3_BLOCKS_PER_GROUP(sb); - if (first_group > last_group) - return -EINVAL; + /* end now represents the last block to discard in this group */ + end = EXT3_BLOCKS_PER_GROUP(sb) - 1; for (group = first_group; group <= last_group; group++) { gdp = ext3_get_group_desc(sb, group, NULL); if (!gdp) break; - free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); - if (free_blocks < minlen) - continue; - /* * For all the groups except the last one, last block will - * always be EXT3_BLOCKS_PER_GROUP(sb), so we only need to - * change it for the last group in which case first_block + - * len < EXT3_BLOCKS_PER_GROUP(sb). + * always be EXT3_BLOCKS_PER_GROUP(sb)-1, so we only need to + * change it for the last group, note that last_block is + * already computed earlier by ext3_get_group_no_and_offset() */ - if (first_block + len < EXT3_BLOCKS_PER_GROUP(sb)) - last_block = first_block + len; - len -= last_block - first_block; + if (group == last_group) + end = last_block; - ret = ext3_trim_all_free(sb, group, first_block, - last_block, minlen); - if (ret < 0) - break; + if (le16_to_cpu(gdp->bg_free_blocks_count) >= minlen) { + ret = ext3_trim_all_free(sb, group, first_block, + end, minlen); + if (ret < 0) + break; + trimmed += ret; + } - trimmed += ret; + /* + * For every group except the first one, we are sure + * that the first block to discard will be block #0. + */ first_block = 0; } - if (ret >= 0) + if (ret > 0) ret = 0; - range->len = trimmed * sb->s_blocksize; +out: + range->len = trimmed * sb->s_blocksize; return ret; }