On Mon, 10 Jan 2011, Jan Kara wrote: > When s_first_data_block is not zero (which happens e.g. when block size is 1KB) > and trim ioctl is called to start trimming from block 0, the math in > ext4_get_group_no_and_offset() overflows. The overall result is that ioctl > returns EINVAL which is kind of unexpected and we probably don't want > userspace tools to bother with internal details of filesystem structure. > So just silently increase starting offset (and shorten length) when starting > block is below s_first_data_block. > > CC: Lukas Czerner <lczerner@xxxxxxxxxx> > Signed-off-by: Jan Kara <jack@xxxxxxx> > --- > fs/ext4/mballoc.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 4c4766c..b9c2aad 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4819,6 +4819,8 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) > ext4_group_t group, ngroups = ext4_get_groups_count(sb); > ext4_grpblk_t cnt = 0, first_block, last_block; > uint64_t start, len, minlen, trimmed; > + ext4_fsblk_t first_data_blk = > + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); > int ret = 0; > > start = range->start >> sb->s_blocksize_bits; > @@ -4828,6 +4830,10 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range) > > if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb))) > return -EINVAL; > + if (start < first_data_blk) { > + len -= first_data_blk - start; > + start = first_data_blk; > + } > > /* Determine first and last group to examine based on start and len */ > ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start, > Hi Ted, forget my previous patch, this is the right one. Thanks Jan! -Lukas -- 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