On Jan 11, 2008 11:28 -0600, Jose R. Santos wrote:
> +blk_t ext2fs_flexbg_offset(ext2_filsys fs, dgrp_t group, int flexbg_size,
> + ext2fs_block_bitmap bmap, int offset, int size)
Could you please add some comments for what this function is trying to do?
> + last_grp = (group + (flexbg_size - (group % flexbg_size) - 1));
Is this the same as:
last_grp = group + (flexbg_size - 1) / flexbg_size * flexbg_size
(i.e. trying to round up to the next even multiple of flexbg_size)?
Didn't we decide to have flexbg_size be a power-of-two value, so we could
use shift and mask instead of divide and mod? It's less of an issue because
group is only a 32-bit value, I guess.
> + if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
> + &first_free))
> + return first_free;
> +
> + if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
> + bmap, &first_free))
> + return first_free;
> +
> + return first_free;
> +}
> +
> errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
> ext2fs_block_bitmap bmap)
> {
> errcode_t retval;
> blk_t group_blk, start_blk, last_blk, new_blk, blk;
> - int j;
> + dgrp_t last_grp;
> + int j, rem_grps, flexbg_size = 0;
>
> group_blk = ext2fs_group_first_block(fs, group);
> last_blk = ext2fs_group_last_block(fs, group);
>
> if (!bmap)
> bmap = fs->block_map;
> +
> + if (EXT2_HAS_INCOMPAT_FEATURE (fs->super,
> + EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
> + flexbg_size = 1 << fs->super->s_log_groups_per_flex;
> + rem_grps = flexbg_size - (group % flexbg_size);
Hmm, no point in doing "groups % flexbg_size" if we have
s_log_groups_per_flex. Could do "groups & (flexbg_size - 1)" instead.
> @@ -101,7 +102,11 @@ int ext2fs_super_and_bgd_loc(ext2_filsys fs,
> + if (flex_bg_size) {
> + if ((group % flex_bg_size) == 0)
> + numblocks -= 2 + fs->inode_blocks_per_group;
Ditto.
> @@ -1045,6 +1046,20 @@ static void PRS(int argc, char *argv[])
> exit(1);
> }
> break;
> + case 'G':
> + flex_bg_size = strtoul(optarg, &tmp, 0);
> + if (*tmp) {
> + com_err(program_name, 0,
> + _("Illegal number for Flex_BG size"));
> + exit(1);
> + }
> + if (flex_bg_size < 2 ||
> + (flex_bg_size & (flex_bg_size-1)) != 0) {
> + com_err(program_name, 0,
> + _("Flex_BG size must be a power of 2"));
> + exit(1);
> + }
> + break;
We've been putting new options under "-E var=value"... I don't know what
Ted's thoughs are on using new option letters, though this one might qualify.
> @@ -1444,6 +1459,16 @@ static void PRS(int argc, char *argv[])
> }
> }
>
> + if(flex_bg_size) {
Space after "if ".
> + shift = 0;
> + tmp = flex_bg_size;
> + while ((tmp >>= 1UL) != 0UL)
> + shift++;
There isn't a "log2" function?
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
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