Re: [PATCH v8 11/27] btrfs: dedupe: Introduce interfaces to resume and cleanup dedupe info

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

Alex Lyakas wrote on 2016/03/29 19:31 +0200:
> Hi Qu, Wang,
>
> On Tue, Mar 22, 2016 at 3:35 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
>> Since we will introduce a new on-disk based dedupe method, introduce new
>> interfaces to resume previous dedupe setup.
>>
>> And since we introduce a new tree for status, also add disable handler
>> for it.
>>
>> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>>   fs/btrfs/dedupe.c  | 269 +++++++++++++++++++++++++++++++++++++++++++++++++----
>>   fs/btrfs/dedupe.h  |  13 +++
>>   fs/btrfs/disk-io.c |  21 ++++-
>>   fs/btrfs/disk-io.h |   1 +
>>   4 files changed, 283 insertions(+), 21 deletions(-)
>>
>> diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
>> index 7ef2c37..1112fec 100644
>> --- a/fs/btrfs/dedupe.c
>> +++ b/fs/btrfs/dedupe.c
>> @@ -21,6 +21,8 @@
>>   #include "transaction.h"
>>   #include "delayed-ref.h"
>>   #include "qgroup.h"
>> +#include "disk-io.h"
>> +#include "locking.h"
>>
>>   struct inmem_hash {
>>          struct rb_node hash_node;
>> @@ -41,10 +43,103 @@ static inline struct inmem_hash *inmem_alloc_hash(u16 type)
>>                          GFP_NOFS);
>>   }
>>
>> +static int init_dedupe_info(struct btrfs_dedupe_info **ret_info, u16 type,
>> +                           u16 backend, u64 blocksize, u64 limit)
>> +{
>> +       struct btrfs_dedupe_info *dedupe_info;
>> +
>> +       dedupe_info = kzalloc(sizeof(*dedupe_info), GFP_NOFS);
>> +       if (!dedupe_info)
>> +               return -ENOMEM;
>> +
>> +       dedupe_info->hash_type = type;
>> +       dedupe_info->backend = backend;
>> +       dedupe_info->blocksize = blocksize;
>> +       dedupe_info->limit_nr = limit;
>> +
>> +       /* only support SHA256 yet */
>> +       dedupe_info->dedupe_driver = crypto_alloc_shash("sha256", 0, 0);
>> +       if (IS_ERR(dedupe_info->dedupe_driver)) {
>> +               int ret;
>> +
>> +               ret = PTR_ERR(dedupe_info->dedupe_driver);
>> +               kfree(dedupe_info);
>> +               return ret;
>> +       }
>> +
>> +       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);
>> +
>> +       *ret_info = dedupe_info;
>> +       return 0;
>> +}
>> +
>> +static int init_dedupe_tree(struct btrfs_fs_info *fs_info,
>> +                           struct btrfs_dedupe_info *dedupe_info)
>> +{
>> +       struct btrfs_root *dedupe_root;
>> +       struct btrfs_key key;
>> +       struct btrfs_path *path;
>> +       struct btrfs_dedupe_status_item *status;
>> +       struct btrfs_trans_handle *trans;
>> +       int ret;
>> +
>> +       path = btrfs_alloc_path();
>> +       if (!path)
>> +               return -ENOMEM;
>> +
>> +       trans = btrfs_start_transaction(fs_info->tree_root, 2);
>> +       if (IS_ERR(trans)) {
>> +               ret = PTR_ERR(trans);
>> +               goto out;
>> +       }
>> +       dedupe_root = btrfs_create_tree(trans, fs_info,
>> +                                      BTRFS_DEDUPE_TREE_OBJECTID);
>> +       if (IS_ERR(dedupe_root)) {
>> +               ret = PTR_ERR(dedupe_root);
>> +               btrfs_abort_transaction(trans, fs_info->tree_root, ret);
>> +               goto out;
>> +       }
>> +       dedupe_info->dedupe_root = dedupe_root;
>> +
>> +       key.objectid = 0;
>> +       key.type = BTRFS_DEDUPE_STATUS_ITEM_KEY;
>> +       key.offset = 0;
>> +
>> +       ret = btrfs_insert_empty_item(trans, dedupe_root, path, &key,
>> +                                     sizeof(*status));
>> +       if (ret < 0) {
>> +               btrfs_abort_transaction(trans, fs_info->tree_root, ret);
>> +               goto out;
>> +       }
>> +
>> +       status = btrfs_item_ptr(path->nodes[0], path->slots[0],
>> +                               struct btrfs_dedupe_status_item);
>> +       btrfs_set_dedupe_status_blocksize(path->nodes[0], status,
>> +                                        dedupe_info->blocksize);
>> +       btrfs_set_dedupe_status_limit(path->nodes[0], status,
>> +                       dedupe_info->limit_nr);
>> +       btrfs_set_dedupe_status_hash_type(path->nodes[0], status,
>> +                       dedupe_info->hash_type);
>> +       btrfs_set_dedupe_status_backend(path->nodes[0], status,
>> +                       dedupe_info->backend);
>> +       btrfs_mark_buffer_dirty(path->nodes[0]);
>> +out:
>> +       btrfs_free_path(path);
>> +       if (ret == 0)
>> +               btrfs_commit_transaction(trans, fs_info->tree_root);
>> +       return ret;
>> +}
>> +
>>   int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend,
>>                          u64 blocksize, u64 limit_nr)
>>   {
>>          struct btrfs_dedupe_info *dedupe_info;
>> +       int create_tree;
>> +       u64 compat_ro_flag = btrfs_super_compat_ro_flags(fs_info->super_copy);
>>          u64 limit = limit_nr;
>>          int ret = 0;
>>
>> @@ -63,6 +158,14 @@ int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend,
>>                  limit = BTRFS_DEDUPE_LIMIT_NR_DEFAULT;
>>          if (backend == BTRFS_DEDUPE_BACKEND_ONDISK && limit_nr != 0)
>>                  limit = 0;
>> +       /* Ondisk backend needs DEDUP RO compat feature */
>> +       if (!(compat_ro_flag & BTRFS_FEATURE_COMPAT_RO_DEDUPE) &&
>> +           backend == BTRFS_DEDUPE_BACKEND_ONDISK)
>> +               return -EOPNOTSUPP;
>> +
>> +       /* Meaningless and unable to enable dedupe for RO fs */
>> +       if (fs_info->sb->s_flags & MS_RDONLY)
>> +               return -EROFS;
>>
>>          dedupe_info = fs_info->dedupe_info;
>>          if (dedupe_info) {
>> @@ -81,29 +184,71 @@ int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend,
>>                  return 0;
>>          }
>>
>> +       dedupe_info = NULL;
>>   enable:
>> -       dedupe_info = kzalloc(sizeof(*dedupe_info), GFP_NOFS);
>> -       if (dedupe_info)
>> +       create_tree = compat_ro_flag & BTRFS_FEATURE_COMPAT_RO_DEDUPE;
>> +
>> +       ret = init_dedupe_info(&dedupe_info, type, backend, blocksize, limit);
>> +       if (ret < 0)
>> +               return ret;
>> +       if (create_tree) {
>> +               ret = init_dedupe_tree(fs_info, dedupe_info);
>> +               if (ret < 0)
>> +                       goto out;
>> +       }
>> +
>> +       fs_info->dedupe_info = dedupe_info;
> I think this leaks memory. If previously we had a valid
> fs_info->dedupe_info, it will remain allocated.

Please check previous patch, or the final dedupe.c.

Just before enable tag:
------

         dedupe_info = fs_info->dedupe_info;
         if (dedupe_info) {
                 /* Check if we are re-enable for different dedupe config */
                 if (dedupe_info->blocksize != blocksize ||
                     dedupe_info->hash_type != type ||
                     dedupe_info->backend != 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 = limit;
                 mutex_unlock(&dedupe_info->lock);
                 return 0;
         }

         dedupe_info = NULL;

------

For any existing dedupe_info, btrfs_dedupe_enable() will either disable 
it or, just modify limit on-fly.

So no leaking.

Thanks for the review.
Qu
>
>
>> +       /* We must ensure dedupe_enabled is modified after dedupe_info */
>> +       smp_wmb();
>> +       fs_info->dedupe_enabled = 1;
>> +out:
>> +       if (ret < 0) {
>> +               crypto_free_shash(dedupe_info->dedupe_driver);
>> +               kfree(dedupe_info);
>> +       }
>> +       return ret;
>> +}
>> +
>> +int btrfs_dedupe_resume(struct btrfs_fs_info *fs_info,
>> +                       struct btrfs_root *dedupe_root)
>> +{
>> +       struct btrfs_dedupe_info *dedupe_info;
>> +       struct btrfs_dedupe_status_item *status;
>> +       struct btrfs_key key;
>> +       struct btrfs_path *path;
>> +       u64 blocksize;
>> +       u64 limit;
>> +       u16 type;
>> +       u16 backend;
>> +       int ret = 0;
>> +
>> +       path = btrfs_alloc_path();
>> +       if (!path)
>>                  return -ENOMEM;
>>
>> -       dedupe_info->hash_type = type;
>> -       dedupe_info->backend = backend;
>> -       dedupe_info->blocksize = blocksize;
>> -       dedupe_info->limit_nr = limit;
>> +       key.objectid = 0;
>> +       key.type = BTRFS_DEDUPE_STATUS_ITEM_KEY;
>> +       key.offset = 0;
>>
>> -       /* Only support SHA256 yet */
>> -       dedupe_info->dedupe_driver = crypto_alloc_shash("sha256", 0, 0);
>> -       if (IS_ERR(dedupe_info->dedupe_driver)) {
>> -               btrfs_err(fs_info, "failed to init sha256 driver");
>> -               ret = PTR_ERR(dedupe_info->dedupe_driver);
>> +       ret = btrfs_search_slot(NULL, dedupe_root, &key, path, 0, 0);
>> +       if (ret > 0) {
>> +               ret = -ENOENT;
>> +               goto out;
>> +       } else if (ret < 0) {
>>                  goto out;
>>          }
>>
>> -       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);
>> +       status = btrfs_item_ptr(path->nodes[0], path->slots[0],
>> +                               struct btrfs_dedupe_status_item);
>> +       blocksize = btrfs_dedupe_status_blocksize(path->nodes[0], status);
>> +       limit = btrfs_dedupe_status_limit(path->nodes[0], status);
>> +       type = btrfs_dedupe_status_hash_type(path->nodes[0], status);
>> +       backend = btrfs_dedupe_status_backend(path->nodes[0], status);
>> +
>> +       ret = init_dedupe_info(&dedupe_info, type, backend, blocksize, limit);
>> +       if (ret < 0)
>> +               goto out;
>> +       dedupe_info->dedupe_root = dedupe_root;
>>
>>          fs_info->dedupe_info = dedupe_info;
>>          /* We must ensure dedupe_enabled is modified after dedupe_info */
>> @@ -111,11 +256,36 @@ enable:
>>          fs_info->dedupe_enabled = 1;
>>
>>   out:
>> -       if (ret < 0)
>> -               kfree(dedupe_info);
>> +       btrfs_free_path(path);
>>          return ret;
>>   }
>>
>> +static void inmem_destroy(struct btrfs_dedupe_info *dedupe_info);
>> +int btrfs_dedupe_cleanup(struct btrfs_fs_info *fs_info)
>> +{
>> +       struct btrfs_dedupe_info *dedupe_info;
>> +
>> +       fs_info->dedupe_enabled = 0;
>> +
>> +       /* same as disable */
>> +       smp_wmb();
>> +       dedupe_info = fs_info->dedupe_info;
>> +       fs_info->dedupe_info = NULL;
>> +
>> +       if (!dedupe_info)
>> +               return 0;
>> +
>> +       if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
>> +               inmem_destroy(dedupe_info);
>> +       if (dedupe_info->dedupe_root) {
>> +               free_root_extent_buffers(dedupe_info->dedupe_root);
>> +               kfree(dedupe_info->dedupe_root);
>> +       }
>> +       crypto_free_shash(dedupe_info->dedupe_driver);
>> +       kfree(dedupe_info);
>> +       return 0;
>> +}
>> +
>>   static int inmem_insert_hash(struct rb_root *root,
>>                               struct inmem_hash *hash, int hash_len)
>>   {
>> @@ -325,6 +495,65 @@ static void inmem_destroy(struct btrfs_dedupe_info *dedupe_info)
>>          mutex_unlock(&dedupe_info->lock);
>>   }
>>
>> +static int remove_dedupe_tree(struct btrfs_root *dedupe_root)
>> +{
>> +       struct btrfs_trans_handle *trans;
>> +       struct btrfs_fs_info *fs_info = dedupe_root->fs_info;
>> +       struct btrfs_path *path;
>> +       struct btrfs_key key;
>> +       struct extent_buffer *node;
>> +       int ret;
>> +       int nr;
>> +
>> +       path = btrfs_alloc_path();
>> +       if (!path)
>> +               return -ENOMEM;
>> +       trans = btrfs_start_transaction(fs_info->tree_root, 2);
>> +       if (IS_ERR(trans)) {
>> +               ret = PTR_ERR(trans);
>> +               goto out;
>> +       }
>> +
>> +       path->leave_spinning = 1;
>> +       key.objectid = 0;
>> +       key.offset = 0;
>> +       key.type = 0;
>> +
>> +       while (1) {
>> +               ret = btrfs_search_slot(trans, dedupe_root, &key, path, -1, 1);
>> +               if (ret < 0)
>> +                       goto out;
>> +               node = path->nodes[0];
>> +               nr = btrfs_header_nritems(node);
>> +               if (nr == 0) {
>> +                       btrfs_release_path(path);
>> +                       break;
>> +               }
>> +               path->slots[0] = 0;
>> +               ret = btrfs_del_items(trans, dedupe_root, path, 0, nr);
>> +               if (ret)
>> +                       goto out;
>> +               btrfs_release_path(path);
>> +       }
>> +
>> +       ret = btrfs_del_root(trans, fs_info->tree_root, &dedupe_root->root_key);
>> +       if (ret)
>> +               goto out;
>> +
>> +       list_del(&dedupe_root->dirty_list);
>> +       btrfs_tree_lock(dedupe_root->node);
>> +       clean_tree_block(trans, fs_info, dedupe_root->node);
>> +       btrfs_tree_unlock(dedupe_root->node);
>> +       btrfs_free_tree_block(trans, dedupe_root, dedupe_root->node, 0, 1);
>> +       free_extent_buffer(dedupe_root->node);
>> +       free_extent_buffer(dedupe_root->commit_root);
>> +       kfree(dedupe_root);
>> +       ret = btrfs_commit_transaction(trans, fs_info->tree_root);
>> +out:
>> +       btrfs_free_path(path);
>> +       return ret;
>> +}
>> +
>>   int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
>>   {
>>          struct btrfs_dedupe_info *dedupe_info;
>> @@ -358,10 +587,12 @@ int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
>>          /* now we are OK to clean up everything */
>>          if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
>>                  inmem_destroy(dedupe_info);
>> +       if (dedupe_info->dedupe_root)
>> +               ret = remove_dedupe_tree(dedupe_info->dedupe_root);
>>
>>          crypto_free_shash(dedupe_info->dedupe_driver);
>>          kfree(dedupe_info);
>> -       return 0;
>> +       return ret;
>>   }
>>
>>   /*
>> diff --git a/fs/btrfs/dedupe.h b/fs/btrfs/dedupe.h
>> index 537f0b8..120e630 100644
>> --- a/fs/btrfs/dedupe.h
>> +++ b/fs/btrfs/dedupe.h
>> @@ -112,6 +112,19 @@ int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend,
>>    */
>>   int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info);
>>
>> + /*
>> + * Restore previous dedupe setup from disk
>> + * Called at mount time
>> + */
>> +int btrfs_dedupe_resume(struct btrfs_fs_info *fs_info,
>> +                      struct btrfs_root *dedupe_root);
>> +
>> +/*
>> + * Cleanup current btrfs_dedupe_info
>> + * Called in umount time
>> + */
>> +int btrfs_dedupe_cleanup(struct btrfs_fs_info *fs_info);
>> +
>>   /*
>>    * Calculate hash for dedup.
>>    * Caller must ensure [start, start + dedupe_bs) has valid data.
>> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
>> index 57ae928..44d098d 100644
>> --- a/fs/btrfs/disk-io.c
>> +++ b/fs/btrfs/disk-io.c
>> @@ -51,6 +51,7 @@
>>   #include "sysfs.h"
>>   #include "qgroup.h"
>>   #include "compression.h"
>> +#include "dedupe.h"
>>
>>   #ifdef CONFIG_X86
>>   #include <asm/cpufeature.h>
>> @@ -2156,7 +2157,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
>>          btrfs_destroy_workqueue(fs_info->extent_workers);
>>   }
>>
>> -static void free_root_extent_buffers(struct btrfs_root *root)
>> +void free_root_extent_buffers(struct btrfs_root *root)
>>   {
>>          if (root) {
>>                  free_extent_buffer(root->node);
>> @@ -2490,7 +2491,21 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info,
>>                  fs_info->free_space_root = root;
>>          }
>>
>> -       return 0;
>> +       location.objectid = BTRFS_DEDUPE_TREE_OBJECTID;
>> +       root = btrfs_read_tree_root(tree_root, &location);
>> +       if (IS_ERR(root)) {
>> +               ret = PTR_ERR(root);
>> +               if (ret != -ENOENT)
>> +                       return ret;
>> +               return 0;
>> +       }
>> +       set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
>> +       ret = btrfs_dedupe_resume(fs_info, root);
>> +       if (ret < 0) {
>> +               free_root_extent_buffers(root);
>> +               kfree(root);
>> +       }
>> +       return ret;
>>   }
>>
>>   int open_ctree(struct super_block *sb,
>> @@ -3885,6 +3900,8 @@ void close_ctree(struct btrfs_root *root)
>>
>>          btrfs_free_qgroup_config(fs_info);
>>
>> +       btrfs_dedupe_cleanup(fs_info);
>> +
>>          if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
>>                  btrfs_info(fs_info, "at unmount delalloc count %lld",
>>                         percpu_counter_sum(&fs_info->delalloc_bytes));
>> diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
>> index 8e79d00..42c4ff2 100644
>> --- a/fs/btrfs/disk-io.h
>> +++ b/fs/btrfs/disk-io.h
>> @@ -70,6 +70,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
>>   int btrfs_init_fs_root(struct btrfs_root *root);
>>   int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
>>                           struct btrfs_root *root);
>> +void free_root_extent_buffers(struct btrfs_root *root);
>>   void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);
>>
>>   struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
>> --
>> 2.7.3
>>
>>
>>
>> --
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>
>