From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:43542 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752211AbcAGBIp (ORCPT ); Wed, 6 Jan 2016 20:08:45 -0500 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id DEAC5409257D for ; Thu, 7 Jan 2016 09:08:20 +0800 (CST) From: Qu Wenruo To: CC: Wang Xiaoguang Subject: [PATCH v3 03/16] btrfs: dedup: Introduce function to add hash into in-memory tree Date: Thu, 7 Jan 2016 09:08:04 +0800 Message-ID: <1452128897-5433-4-git-send-email-quwenruo@cn.fujitsu.com> In-Reply-To: <1452128897-5433-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1452128897-5433-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-btrfs-owner@vger.kernel.org List-ID: From: Wang Xiaoguang Introduce static function inmem_add() to add hash into in-memory tree. And now we can implement the btrfs_dedup_add() interface. Sgined-o Signed-off-by: Wang Xiaoguang --- v3: Use specific struct inmem_hash for inmem backend Handle corner case where same bytenr may have 2 different hashes. --- fs/btrfs/dedup.c | 165 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) diff --git a/fs/btrfs/dedup.c b/fs/btrfs/dedup.c index c1fadff..279f50b 100644 --- a/fs/btrfs/dedup.c +++ b/fs/btrfs/dedup.c @@ -21,6 +21,25 @@ #include "transaction.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 inline struct inmem_hash *inmem_alloc_hash(u16 type) +{ + if (WARN_ON(type >= ARRAY_SIZE(btrfs_dedup_sizes))) + return NULL; + return kzalloc(sizeof(struct inmem_hash) + btrfs_dedup_sizes[type], + GFP_NOFS); +} + int btrfs_dedup_enable(struct btrfs_fs_info *fs_info, u16 type, u16 backend, u64 blocksize, u64 limit) { @@ -94,3 +113,149 @@ out: } return ret; } + +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_dedup_info *dedup_info, + struct inmem_hash *hash) +{ + list_del(&hash->lru_list); + rb_erase(&hash->hash_node, &dedup_info->hash_root); + rb_erase(&hash->bytenr_node, &dedup_info->bytenr_root); + + if (!WARN_ON(dedup_info->current_nr == 0)) + dedup_info->current_nr--; + + kfree(hash); +} + +/* + * Insert a hash into in-memory dedup 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_dedup_info *dedup_info, + struct btrfs_dedup_hash *hash) +{ + int ret = 0; + u16 type = dedup_info->hash_type; + struct inmem_hash *ihash; + + ihash = inmem_alloc_hash(type); + + if (!ihash) + return -ENOMEM; + + /* Copy the data out */ + ihash->bytenr = hash->bytenr; + ihash->num_bytes = hash->num_bytes; + memcpy(ihash->hash, hash->hash, btrfs_dedup_sizes[type]); + + spin_lock(&dedup_info->lock); + + /* + * Insert bytenr node first + * It is *POSSIBLE* that same bytenr has different hash, + * since hash is added at finish_ordered_io, but freed + * at delayed_ref time. + * If a extent is allocated and freed, then reallocated in the + * same trans, same bytenr will has different hash. + * So let insert_bytenr to handle it. + * TODO: Maybe just free previous inmem_hash would be better? + */ + ret = inmem_insert_bytenr(&dedup_info->bytenr_root, ihash); + if (ret > 0) { + kfree(ihash); + ret = 0; + goto out; + } + + ret = inmem_insert_hash(&dedup_info->hash_root, ihash, + btrfs_dedup_sizes[type]); + if (ret > 0) { + /* + * We only keep one hash in tree to save memory, so if + * hash conflicts, free current one. + */ + rb_erase(&ihash->bytenr_node, &dedup_info->bytenr_root); + kfree(ihash); + ret = 0; + goto out; + } + + list_add(&ihash->lru_list, &dedup_info->lru_list); + dedup_info->current_nr++; + + /* Remove the last dedup hash if we exceed limit */ + while (dedup_info->current_nr > dedup_info->limit_nr) { + struct inmem_hash *last; + + last = list_entry(dedup_info->lru_list.prev, + struct inmem_hash, lru_list); + __inmem_del(dedup_info, last); + } +out: + spin_unlock(&dedup_info->lock); + return 0; +} + +int btrfs_dedup_add(struct btrfs_trans_handle *trans, struct btrfs_root *root, + struct btrfs_dedup_hash *hash) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_dedup_info *dedup_info = fs_info->dedup_info; + + if (!dedup_info || !hash) + return 0; + + if (WARN_ON(hash->bytenr == 0)) + return -EINVAL; + + if (dedup_info->backend == BTRFS_DEDUP_BACKEND_INMEMORY) + return inmem_add(dedup_info, hash); + return -EINVAL; +} -- 2.6.4