From: Tao Ma <boyu.mt@xxxxxxxxxx> We adjust 'len' with s_first_data_block - start in case of start is less than s_first_data_block, but it could underflow in case blocksize=1K, while fstrim_range.len=512 and fstrim_range.start = 0. In this case len happens to be underflow and in the end, although we are safe that last_group check will limit the trim to the whole volume, I am afraid that isn't what the user really want. So this patch fix it. It also adds a new variable s_first_data_block so that the 4 le32_to_cpu can be replaced with 1. Cc: Jan Kara <jack@xxxxxxx> Cc: Lukas Czerner <lczerner@xxxxxxxxxx> Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> --- fs/ext3/balloc.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index 045995c..ee7e0f3 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -2088,6 +2088,7 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range) struct ext3_super_block *es = EXT3_SB(sb)->s_es; uint64_t start, len, minlen, trimmed; ext3_fsblk_t max_blks = le32_to_cpu(es->s_blocks_count); + ext3_fsblk_t first_data_block = le32_to_cpu(es->s_first_data_block); int ret = 0; start = range->start >> sb->s_blocksize_bits; @@ -2097,11 +2098,11 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range) if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb))) return -EINVAL; - if (start >= max_blks) + if (start >= max_blks || start + len <= first_data_block) goto out; - if (start < le32_to_cpu(es->s_first_data_block)) { - len -= le32_to_cpu(es->s_first_data_block) - start; - start = le32_to_cpu(es->s_first_data_block); + if (start < first_data_block) { + len -= first_data_block - start; + start = first_data_block; } if (start + len > max_blks) len = max_blks - start; -- 1.6.3.GIT -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html