Re: [PATCH v15.1 02/13] btrfs: dedupe: Introduce function to initialize dedupe info

[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>
>
> Add generic function to initialize dedupe info.
>
> 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/Makefile          |   2 +-
>  fs/btrfs/dedupe.c          | 169 +++++++++++++++++++++++++++++++++++++
>  fs/btrfs/dedupe.h          |  12 +++
>  include/uapi/linux/btrfs.h |   3 +
>  4 files changed, 185 insertions(+), 1 deletion(-)
>  create mode 100644 fs/btrfs/dedupe.c
>
> diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
> index ca693dd554e9..78fdc87dba39 100644
> --- a/fs/btrfs/Makefile
> +++ b/fs/btrfs/Makefile
> @@ -10,7 +10,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
>            export.o tree-log.o free-space-cache.o zlib.o lzo.o zstd.o \
>            compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \
>            reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
> -          uuid-tree.o props.o free-space-tree.o tree-checker.o
> +          uuid-tree.o props.o free-space-tree.o tree-checker.o dedupe.o
>
>  btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
>  btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
> diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
> new file mode 100644
> index 000000000000..06523162753d
> --- /dev/null
> +++ b/fs/btrfs/dedupe.c
> @@ -0,0 +1,169 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2016 Fujitsu.  All rights reserved.
> + */
> +
> +#include "ctree.h"
> +#include "dedupe.h"
> +#include "btrfs_inode.h"
> +#include "delayed-ref.h"
> +
> +struct inmem_hash {
> +       struct rb_node hash_node;
> +       struct rb_node bytenr_node;
> +       struct list_head lru_list;
> +
> +       u64 bytenr;
> +       u32 num_bytes;
> +
> +       u8 hash[];
> +};
> +
> +static struct btrfs_dedupe_info *
> +init_dedupe_info(struct btrfs_ioctl_dedupe_args *dargs)
> +{
> +       struct btrfs_dedupe_info *dedupe_info;
> +
> +       dedupe_info = kzalloc(sizeof(*dedupe_info), GFP_NOFS);
> +       if (!dedupe_info)
> +               return ERR_PTR(-ENOMEM);
> +
> +       dedupe_info->hash_algo = dargs->hash_algo;
> +       dedupe_info->backend = dargs->backend;
> +       dedupe_info->blocksize = dargs->blocksize;
> +       dedupe_info->limit_nr = dargs->limit_nr;
> +
> +       /* only support SHA256 yet */
> +       dedupe_info->dedupe_driver = crypto_alloc_shash("sha256", 0, 0);
> +       if (IS_ERR(dedupe_info->dedupe_driver)) {
> +               kfree(dedupe_info);
> +               return ERR_CAST(dedupe_info->dedupe_driver);
> +       }
> +
> +       dedupe_info->hash_root = RB_ROOT;
> +       dedupe_info->bytenr_root = RB_ROOT;
> +       dedupe_info->current_nr = 0;
> +       INIT_LIST_HEAD(&dedupe_info->lru_list);
> +       mutex_init(&dedupe_info->lock);
> +
> +       return dedupe_info;
> +}
> +
> +/*
> + * Helper to check if parameters are valid.
> + * The first invalid field will be set to (-1), to info user which parameter
> + * is invalid.
> + * Except dargs->limit_nr or dargs->limit_mem, in that case, 0 will returned
> + * to info user, since user can specify any value to limit, except 0.
> + */
> +static int check_dedupe_parameter(struct btrfs_fs_info *fs_info,
> +                                 struct btrfs_ioctl_dedupe_args *dargs)
> +{
> +       u64 blocksize = dargs->blocksize;
> +       u64 limit_nr = dargs->limit_nr;
> +       u64 limit_mem = dargs->limit_mem;
> +       u16 hash_algo = dargs->hash_algo;
> +       u8 backend = dargs->backend;
> +
> +       /*
> +        * Set all reserved fields to -1, allow user to detect
> +        * unsupported optional parameters.
> +        */
> +       memset(dargs->__unused, -1, sizeof(dargs->__unused));
> +       if (blocksize > BTRFS_DEDUPE_BLOCKSIZE_MAX ||
> +           blocksize < BTRFS_DEDUPE_BLOCKSIZE_MIN ||
> +           blocksize < fs_info->sectorsize ||
> +           !is_power_of_2(blocksize) ||
> +           blocksize < PAGE_SIZE) {
> +               dargs->blocksize = (u64)-1;
> +               return -EINVAL;
> +       }
> +       if (hash_algo >= ARRAY_SIZE(btrfs_hash_sizes)) {
> +               dargs->hash_algo = (u16)-1;
> +               return -EINVAL;
> +       }
> +       if (backend >= BTRFS_DEDUPE_BACKEND_COUNT) {
> +               dargs->backend = (u8)-1;
> +               return -EINVAL;
> +       }
> +
> +       /* Backend specific check */
> +       if (backend == BTRFS_DEDUPE_BACKEND_INMEMORY) {
> +               /* only one limit is accepted for enable*/
> +               if (dargs->limit_nr && dargs->limit_mem) {
> +                       dargs->limit_nr = 0;
> +                       dargs->limit_mem = 0;
> +                       return -EINVAL;
> +               }
> +
> +               if (!limit_nr && !limit_mem)
> +                       dargs->limit_nr = BTRFS_DEDUPE_LIMIT_NR_DEFAULT;
> +               else {
> +                       u64 tmp = (u64)-1;
> +
> +                       if (limit_mem) {
> +                               tmp = div_u64(limit_mem,
> +                                       (sizeof(struct inmem_hash)) +
> +                                       btrfs_hash_sizes[hash_algo]);
> +                               /* Too small limit_mem to fill a hash item */
> +                               if (!tmp) {
> +                                       dargs->limit_mem = 0;
> +                                       dargs->limit_nr = 0;
> +                                       return -EINVAL;
> +                               }
> +                       }
> +                       if (!limit_nr)
> +                               limit_nr = (u64)-1;
> +
> +                       dargs->limit_nr = min(tmp, limit_nr);
> +               }
> +       }
> +       if (backend == BTRFS_DEDUPE_BACKEND_ONDISK)
> +               dargs->limit_nr = 0;
> +
> +       return 0;
> +}
> +
> +int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info,
> +                       struct btrfs_ioctl_dedupe_args *dargs)
> +{
> +       struct btrfs_dedupe_info *dedupe_info;
> +       int ret = 0;
> +
> +       ret = check_dedupe_parameter(fs_info, dargs);
> +       if (ret < 0)
> +               return ret;
> +
> +       dedupe_info = fs_info->dedupe_info;
> +       if (dedupe_info) {
> +               /* Check if we are re-enable for different dedupe config */
> +               if (dedupe_info->blocksize != dargs->blocksize ||
> +                   dedupe_info->hash_algo != dargs->hash_algo ||
> +                   dedupe_info->backend != dargs->backend) {
> +                       btrfs_dedupe_disable(fs_info);
> +                       goto enable;
> +               }
> +
> +               /* On-fly limit change is OK */
> +               mutex_lock(&dedupe_info->lock);
> +               fs_info->dedupe_info->limit_nr = dargs->limit_nr;
> +               mutex_unlock(&dedupe_info->lock);
> +               return 0;
> +       }
> +
> +enable:
> +       dedupe_info = init_dedupe_info(dargs);
> +       if (IS_ERR(dedupe_info))
> +               return PTR_ERR(dedupe_info);
> +       fs_info->dedupe_info = dedupe_info;
> +       /* We must ensure dedupe_bs is modified after dedupe_info */
> +       smp_wmb();
> +       fs_info->dedupe_enabled = 1;
> +       return ret;
> +}
> +
> +int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
> +{
> +       /* Place holder for bisect, will be implemented in later patches */
> +       return 0;
> +}
> diff --git a/fs/btrfs/dedupe.h b/fs/btrfs/dedupe.h
> index 222ce7b4d827..87f5b7ce7766 100644
> --- a/fs/btrfs/dedupe.h
> +++ b/fs/btrfs/dedupe.h
> @@ -52,6 +52,18 @@ static inline int btrfs_dedupe_hash_hit(struct btrfs_dedupe_hash *hash)
>         return (hash && hash->bytenr);
>  }
>
> +static inline int btrfs_dedupe_hash_size(u16 algo)
> +{
> +       if (WARN_ON(algo >= ARRAY_SIZE(btrfs_hash_sizes)))
> +               return -EINVAL;
> +       return sizeof(struct btrfs_dedupe_hash) + btrfs_hash_sizes[algo];
> +}
> +
> +static inline struct btrfs_dedupe_hash *btrfs_dedupe_alloc_hash(u16 algo)
> +{
> +       return kzalloc(btrfs_dedupe_hash_size(algo), GFP_NOFS);
> +}
> +
>  /*
>   * Initial inband dedupe info
>   * Called at dedupe enable time.
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index 9cd15d2a40aa..ba879ac931f2 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h
> @@ -683,6 +683,9 @@ struct btrfs_ioctl_get_dev_stats {
>  /* Hash algorithm, only support SHA256 yet */
>  #define BTRFS_DEDUPE_HASH_SHA256               0
>
> +/* Default dedupe limit on number of hash */
> +#define BTRFS_DEDUPE_LIMIT_NR_DEFAULT  (32 * 1024)
> +
>  /*
>   * This structure is used for dedupe enable/disable/configure
>   * and status ioctl.
> --
> 2.19.1
>
>
>
Reviewed-by: Timofey Titovets <nefelim4ag@gmail.com>

Thanks.

-- 
Have a nice day,
Timofey.