lkml.org 
[lkml]   [2011]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH v6] fat: Batched discard support for fat
    Date
    Kyungmin Park <kmpark@infradead.org> writes:

    > +int fat_trim_fs(struct super_block *sb, struct fstrim_range *range)
    > +{
    > + struct msdos_sb_info *sbi = MSDOS_SB(sb);
    > + struct fatent_operations *ops = sbi->fatent_ops;
    > + struct fat_entry fatent;
    > + unsigned long reada_blocks, reada_mask, cur_block;
    > + int err, free, count, entry;
    > + int start, len, minlen, trimmed;
    > +
    > + start = range->start >> sb->s_blocksize_bits;
    > + len = range->len >> sb->s_blocksize_bits;
    > + len = round_down(start + len, sbi->sec_per_clus);
    > + start = round_up(start, sbi->sec_per_clus);
    > + minlen = range->minlen >> sb->s_blocksize_bits;
    > + minlen = round_up(minlen, sbi->sec_per_clus);
    > + trimmed = 0;
    > + count = 0;
    > + err = -EINVAL;

    Sorry for didn't mention at previous. You can use ->cluster_size, and
    ->cluster_bits.

    > + if (start >= sbi->max_cluster)
    > + goto out;
    > +
    > + len = (len > sbi->max_cluster) ? sbi->max_cluster : len;

    [...]

    > + trimmed += free;
    > + }
    > + range->len = (u64)(trimmed * sbi->sec_per_clus) << sb->s_blocksize_bits;
    > + fatent_brelse(&fatent);
    > +out:
    > + unlock_fat(sbi);
    > + return err;

    Again, this ioctl's design is unclear, and seems to be strange. I
    wouldn't want to add this before clearing it. Please explain what is
    right behavior.

    E.g. if user specified 0-1024 and FS data block was actually started at
    2048. What is right behavior? And if the end of blocks, what returned?
    For now, it seems to return range->len == 0 on both cases.

    Well, so, my suggestion is providing this like flat one extent
    file. I.e. FS have to map actual block placement to flat. And result
    also like write/read (return bytes as trimed, and at EOF returns 0).

    Thanks.
    --
    OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>


    \
     
     \ /
      Last update: 2011-03-29 07:07    [W:0.022 / U:34.380 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site