On Tue, Aug 23, 2011 at 11:01:51PM +0300, Ilya Dryomov wrote:
> Select chunks that are less than X percent full.
>
> Signed-off-by: Ilya Dryomov <idryo...@gmail.com>
> ---
> fs/btrfs/volumes.c | 33 +++++++++++++++++++++++++++++++++
> fs/btrfs/volumes.h | 1 +
> 2 files changed, 34 insertions(+), 0 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index f045615..b49ecfa 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -2193,6 +2193,33 @@ static int chunk_profiles_filter(u64 chunk_profile,
> return 1;
> }
>
> +static u64 div_factor_fine(u64 num, int factor)
> +{
factor is obtained from userspace via btrfs_restripe_args and should
imhoe be checked for safety.
> + if (factor == 100)
something like this (if the type is really 'int')
if (factor < 0 || factor >= 100)
> + return num;
> + num *= factor;
> + do_div(num, 100);
> + return num;
> +}
> +
> +static int chunk_usage_filter(struct btrfs_fs_info *fs_info, u64
> chunk_offset,
> + struct btrfs_restripe_args *rargs)
> +{
> + struct btrfs_block_group_cache *cache;
> + u64 chunk_used, user_thresh;
> + int ret = 1;
> +
> + cache = btrfs_lookup_block_group(fs_info, chunk_offset);
> + chunk_used = btrfs_block_group_used(&cache->item);
> +
> + user_thresh = div_factor_fine(cache->key.offset, rargs->usage);
^^^^^^^^^^^^
does not seem right, but AFAICS is harmless, if an overflow occurs
> + if (chunk_used < user_thresh)
> + ret = 0;
will result in ret = 1 and code below will do not continue restriping
> +
> + btrfs_put_block_group(cache);
> + return ret;
> +}
> +
> static int chunk_soft_convert_filter(u64 chunk_profile,
> struct btrfs_restripe_args *rargs)
> {
> @@ -2236,6 +2263,12 @@ static int should_restripe_chunk(struct btrfs_root
> *root,
> return 0;
> }
>
> + /* usage filter */
> + if ((rargs->flags & BTRFS_RESTRIPE_ARGS_USAGE) &&
> + chunk_usage_filter(rctl->fs_info, chunk_offset, rargs)) {
^^^
will skip restriping chunk (if the previous holds).
> + return 0;
> + }
> +
> /* soft profile changing mode */
> if ((rargs->flags & BTRFS_RESTRIPE_ARGS_SOFT) &&
> chunk_soft_convert_filter(chunk_type, rargs)) {
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index 9f96ad8..c6baf4b 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -186,6 +186,7 @@ struct map_lookup {
> * Restripe filters
> */
> #define BTRFS_RESTRIPE_ARGS_PROFILES (1ULL << 0)
> +#define BTRFS_RESTRIPE_ARGS_USAGE (1ULL << 1)
>
> /*
> * Profile changing flags. When SOFT is set we won't relocate chunk if
> --
> 1.7.5.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
