Re: [PATCH v15.1 03/13] btrfs: dedupe: Introduce function to add hash into in-memory tree

[Timofey Titovets <nefelim4ag@gmail.com>]

вт, 6 нояб. 2018 г. в 9:41, Lu Fengqi <lufq.fnst@cn.fujitsu.com>:
>
> From: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
>
> Introduce static function inmem_add() to add hash into in-memory tree.
> And now we can implement the btrfs_dedupe_add() interface.
>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
> Reviewed-by: Josef Bacik <jbacik@fb.com>
> Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
> ---
>  fs/btrfs/dedupe.c | 150 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 150 insertions(+)
>
> diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
> index 06523162753d..784bb3a8a5ab 100644
> --- a/fs/btrfs/dedupe.c
> +++ b/fs/btrfs/dedupe.c
> @@ -19,6 +19,14 @@ struct inmem_hash {
>         u8 hash[];
>  };
>
> +static inline struct inmem_hash *inmem_alloc_hash(u16 algo)
> +{
> +       if (WARN_ON(algo >= ARRAY_SIZE(btrfs_hash_sizes)))
> +               return NULL;
> +       return kzalloc(sizeof(struct inmem_hash) + btrfs_hash_sizes[algo],
> +                       GFP_NOFS);
> +}
> +
>  static struct btrfs_dedupe_info *
>  init_dedupe_info(struct btrfs_ioctl_dedupe_args *dargs)
>  {
> @@ -167,3 +175,145 @@ int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
>         /* Place holder for bisect, will be implemented in later patches */
>         return 0;
>  }
> +
> +static int inmem_insert_hash(struct rb_root *root,
> +                            struct inmem_hash *hash, int hash_len)
> +{
> +       struct rb_node **p = &root->rb_node;
> +       struct rb_node *parent = NULL;
> +       struct inmem_hash *entry = NULL;
> +
> +       while (*p) {
> +               parent = *p;
> +               entry = rb_entry(parent, struct inmem_hash, hash_node);
> +               if (memcmp(hash->hash, entry->hash, hash_len) < 0)
> +                       p = &(*p)->rb_left;
> +               else if (memcmp(hash->hash, entry->hash, hash_len) > 0)
> +                       p = &(*p)->rb_right;
> +               else
> +                       return 1;
> +       }
> +       rb_link_node(&hash->hash_node, parent, p);
> +       rb_insert_color(&hash->hash_node, root);
> +       return 0;
> +}
> +
> +static int inmem_insert_bytenr(struct rb_root *root,
> +                              struct inmem_hash *hash)
> +{
> +       struct rb_node **p = &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 (hash->bytenr < entry->bytenr)
> +                       p = &(*p)->rb_left;
> +               else if (hash->bytenr > entry->bytenr)
> +                       p = &(*p)->rb_right;
> +               else
> +                       return 1;
> +       }
> +       rb_link_node(&hash->bytenr_node, parent, p);
> +       rb_insert_color(&hash->bytenr_node, root);
> +       return 0;
> +}
> +
> +static void __inmem_del(struct btrfs_dedupe_info *dedupe_info,
> +                       struct inmem_hash *hash)
> +{
> +       list_del(&hash->lru_list);
> +       rb_erase(&hash->hash_node, &dedupe_info->hash_root);
> +       rb_erase(&hash->bytenr_node, &dedupe_info->bytenr_root);
> +
> +       if (!WARN_ON(dedupe_info->current_nr == 0))
> +               dedupe_info->current_nr--;
> +
> +       kfree(hash);
> +}
> +
> +/*
> + * Insert a hash into in-memory dedupe tree
> + * Will remove exceeding last recent use hash.
> + *
> + * If the hash mathced with existing one, we won't insert it, to
> + * save memory
> + */
> +static int inmem_add(struct btrfs_dedupe_info *dedupe_info,
> +                    struct btrfs_dedupe_hash *hash)
> +{
> +       int ret = 0;
> +       u16 algo = dedupe_info->hash_algo;
> +       struct inmem_hash *ihash;
> +
> +       ihash = inmem_alloc_hash(algo);
> +
> +       if (!ihash)
> +               return -ENOMEM;
> +
> +       /* Copy the data out */
> +       ihash->bytenr = hash->bytenr;
> +       ihash->num_bytes = hash->num_bytes;
> +       memcpy(ihash->hash, hash->hash, btrfs_hash_sizes[algo]);
> +
> +       mutex_lock(&dedupe_info->lock);
> +
> +       ret = inmem_insert_bytenr(&dedupe_info->bytenr_root, ihash);
> +       if (ret > 0) {
> +               kfree(ihash);
> +               ret = 0;
> +               goto out;
> +       }
> +
> +       ret = inmem_insert_hash(&dedupe_info->hash_root, ihash,
> +                               btrfs_hash_sizes[algo]);
> +       if (ret > 0) {
> +               /*
> +                * We only keep one hash in tree to save memory, so if
> +                * hash conflicts, free the one to insert.
> +                */
> +               rb_erase(&ihash->bytenr_node, &dedupe_info->bytenr_root);
> +               kfree(ihash);
> +               ret = 0;
> +               goto out;
> +       }
> +
> +       list_add(&ihash->lru_list, &dedupe_info->lru_list);
> +       dedupe_info->current_nr++;
> +
> +       /* Remove the last dedupe hash if we exceed limit */
> +       while (dedupe_info->current_nr > dedupe_info->limit_nr) {
> +               struct inmem_hash *last;
> +
> +               last = list_entry(dedupe_info->lru_list.prev,
> +                                 struct inmem_hash, lru_list);
> +               __inmem_del(dedupe_info, last);
> +       }
> +out:
> +       mutex_unlock(&dedupe_info->lock);
> +       return 0;
> +}
> +
> +int btrfs_dedupe_add(struct btrfs_fs_info *fs_info,
> +                    struct btrfs_dedupe_hash *hash)
> +{
> +       struct btrfs_dedupe_info *dedupe_info = fs_info->dedupe_info;
> +
> +       if (!fs_info->dedupe_enabled || !hash)
> +               return 0;
> +
> +       if (WARN_ON(dedupe_info == NULL))
> +               return -EINVAL;
> +
> +       if (WARN_ON(!btrfs_dedupe_hash_hit(hash)))
> +               return -EINVAL;
> +
> +       /* ignore old hash */
> +       if (dedupe_info->blocksize != hash->num_bytes)
> +               return 0;
> +
> +       if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
> +               return inmem_add(dedupe_info, hash);
> +       return -EINVAL;
> +}
> --
> 2.19.1
>
>
>

Reviewed-by: Timofey Titovets <nefelim4ag@gmail.com>

Thanks.

-- 
Have a nice day,
Timofey.