On Sun, 8 Aug 2010, Jan Kara wrote: > On Fri 06-08-10 13:31:16, Lukas Czerner wrote: > ... > > +/** > > + * ext4_trim_fs() -- trim ioctl handle function > > + * @sb: superblock for filesystem > > + * @start: First Byte to trim > > + * @len: number of Bytes to trim from start > > + * @minlen: minimum extent length in Bytes > > + * > > + * ext4_trim_fs goes through all allocation groups containing Bytes from > > + * start to start+len. For each such a group ext4_trim_all_free function > > + * is invoked to trim all free space. > > + */ > > +int ext4_trim_fs(struct super_block *sb, uint64_t start, uint64_t len, > > + uint64_t minlen) > > +{ > > + struct ext4_buddy e4b; > > + ext4_fsblk_t first_group, last_group; > > + ext4_group_t group, ngroups = ext4_get_groups_count(sb); > > + ext4_grpblk_t cnt, first_block, last_block; > > + struct ext4_super_block *es = EXT4_SB(sb)->s_es; > > + int ret = 0; > > + > > + start >>= sb->s_blocksize_bits; > > + len >>= sb->s_blocksize_bits; > > + minlen >>= sb->s_blocksize_bits; > > + > > + if (unlikely(minlen > EXT4_BLOCKS_PER_GROUP(sb))) > > + return -EINVAL; > > + > > + /* Determine first and last group to examine based on start and len */ > > + first_group = (start - le32_to_cpu(es->s_first_data_block)) / > > + EXT4_BLOCKS_PER_GROUP(sb); > > + last_group = (start + len - le32_to_cpu(es->s_first_data_block)) / > > + EXT4_BLOCKS_PER_GROUP(sb); > > + last_group = (last_group > ngroups - 1) ? ngroups - 1 : last_group; > > + > > + if (first_group > last_group) > > + return -EINVAL; > > + > > + first_block = start % EXT4_BLOCKS_PER_GROUP(sb); > I think you should substract "le32_to_cpu(es->s_first_data_block)" from > the start before doing modulo. > > Honza Oh, right thanks. -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