On Fri, Apr 01, 2016 at 02:34:55PM +0800, Qu Wenruo wrote:
> From: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
>
> Introduce static function inmem_del() to remove hash from in-memory
> dedupe tree.
> And implement btrfs_dedupe_del() and btrfs_dedup_destroy() interfaces.
>
> Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/dedupe.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 105 insertions(+)
>
> diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
> index 4e8455e..a229ded 100644
> --- a/fs/btrfs/dedupe.c
> +++ b/fs/btrfs/dedupe.c
> @@ -303,3 +303,108 @@ int btrfs_dedupe_add(struct btrfs_trans_handle *trans,
> return inmem_add(dedupe_info, hash);
> return -EINVAL;
> }
> +
> +static struct inmem_hash *
> +inmem_search_bytenr(struct btrfs_dedupe_info *dedupe_info, u64 bytenr)
> +{
> + struct rb_node **p = &dedupe_info->bytenr_root.rb_node;
> + struct rb_node *parent = NULL;
> + struct inmem_hash *entry = NULL;
> +
> + while (*p) {
> + parent = *p;
> + entry = rb_entry(parent, struct inmem_hash, bytenr_node);
> +
> + if (bytenr < entry->bytenr)
> + p = &(*p)->rb_left;
> + else if (bytenr > entry->bytenr)
> + p = &(*p)->rb_right;
> + else
> + return entry;
> + }
> +
> + return NULL;
> +}
> +
> +/* Delete a hash from in-memory dedupe tree */
> +static int inmem_del(struct btrfs_dedupe_info *dedupe_info, u64 bytenr)
> +{
> + struct inmem_hash *hash;
> +
> + mutex_lock(&dedupe_info->lock);
> + hash = inmem_search_bytenr(dedupe_info, bytenr);
> + if (!hash) {
> + mutex_unlock(&dedupe_info->lock);
> + return 0;
> + }
> +
> + __inmem_del(dedupe_info, hash);
> + mutex_unlock(&dedupe_info->lock);
> + return 0;
> +}
> +
> +/* Remove a dedupe hash from dedupe tree */
> +int btrfs_dedupe_del(struct btrfs_trans_handle *trans,
> + struct btrfs_fs_info *fs_info, u64 bytenr)
> +{
> + struct btrfs_dedupe_info *dedupe_info = fs_info->dedupe_info;
> +
> + if (!fs_info->dedupe_enabled)
> + return 0;
> +
> + if (WARN_ON(dedupe_info == NULL))
> + return -EINVAL;
> +
> + if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
> + return inmem_del(dedupe_info, bytenr);
> + return -EINVAL;
> +}
> +
> +static void inmem_destroy(struct btrfs_dedupe_info *dedupe_info)
> +{
> + struct inmem_hash *entry, *tmp;
> +
> + mutex_lock(&dedupe_info->lock);
> + list_for_each_entry_safe(entry, tmp, &dedupe_info->lru_list, lru_list)
> + __inmem_del(dedupe_info, entry);
> + mutex_unlock(&dedupe_info->lock);
> +}
> +
> +int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
> +{
> + struct btrfs_dedupe_info *dedupe_info;
> + int ret;
> +
> + /* Here we don't want to increase refs of dedupe_info */
> + fs_info->dedupe_enabled = 0;
Can this clear of fs_info->dedupe_enabled race with another thread in write?
I don't see any locking (but perhaps that comes in a later patch).
--Mark
--
Mark Fasheh
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