From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:62526 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1758594AbcDAGfq (ORCPT ); Fri, 1 Apr 2016 02:35:46 -0400 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Wang Xiaoguang Subject: [PATCH v10 18/21] btrfs: dedupe: Add support for on-disk hash search Date: Fri, 1 Apr 2016 14:35:09 +0800 Message-Id: <1459492512-31435-19-git-send-email-quwenruo@cn.fujitsu.com> In-Reply-To: <1459492512-31435-1-git-send-email-quwenruo@cn.fujitsu.com> References: <1459492512-31435-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Now on-disk backend should be able to search hash now. Signed-off-by: Wang Xiaoguang Signed-off-by: Qu Wenruo --- fs/btrfs/dedupe.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++------ fs/btrfs/dedupe.h | 1 + 2 files changed, 151 insertions(+), 17 deletions(-) diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c index a274c1c..00f2a01 100644 --- a/fs/btrfs/dedupe.c +++ b/fs/btrfs/dedupe.c @@ -652,6 +652,112 @@ int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info) } /* + * Compare ondisk hash with src. + * Return 0 if hash matches. + * Return non-zero for hash mismatch + * + * Caller should ensure the slot contains a valid hash item. + */ +static int memcmp_ondisk_hash(const struct btrfs_key *key, + struct extent_buffer *node, int slot, + int hash_len, const u8 *src) +{ + u64 offset; + int ret; + + /* Return value doesn't make sense in this case though */ + if (WARN_ON(hash_len <= 8 || key->type != BTRFS_DEDUPE_HASH_ITEM_KEY)) + return -EINVAL; + + /* compare the hash exlcuding the last 64 bits */ + offset = btrfs_item_ptr_offset(node, slot); + ret = memcmp_extent_buffer(node, src, offset, hash_len - 8); + if (ret) + return ret; + return memcmp(&key->objectid, src + hash_len - 8, 8); +} + + /* + * Return 0 for not found + * Return >0 for found and set bytenr_ret + * Return <0 for error + */ +static int ondisk_search_hash(struct btrfs_dedupe_info *dedupe_info, u8 *hash, + u64 *bytenr_ret, u32 *num_bytes_ret) +{ + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_root *dedupe_root = dedupe_info->dedupe_root; + u8 *buf = NULL; + u64 hash_key; + int hash_len = btrfs_dedupe_sizes[dedupe_info->hash_type]; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + buf = kmalloc(hash_len, GFP_NOFS); + if (!buf) { + ret = -ENOMEM; + goto out; + } + + memcpy(&hash_key, hash + hash_len - 8, 8); + key.objectid = hash_key; + key.type = BTRFS_DEDUPE_HASH_ITEM_KEY; + key.offset = (u64)-1; + + ret = btrfs_search_slot(NULL, dedupe_root, &key, path, 0, 0); + if (ret < 0) + goto out; + WARN_ON(ret == 0); + while (1) { + struct extent_buffer *node; + struct btrfs_dedupe_hash_item *hash_item; + int slot; + + ret = btrfs_previous_item(dedupe_root, path, hash_key, + BTRFS_DEDUPE_HASH_ITEM_KEY); + if (ret < 0) + break; + if (ret > 0) { + ret = 0; + break; + } + + node = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(node, &key, slot); + + /* + * Type of objectid mismatch means no previous item may + * hit, exit searching + */ + if (key.type != BTRFS_DEDUPE_HASH_ITEM_KEY || + memcmp(&key.objectid, &hash_key, 8)) + break; + hash_item = btrfs_item_ptr(node, slot, + struct btrfs_dedupe_hash_item); + /* + * If the hash mismatch, it's still possible that previous item + * has the desired hash. + */ + if (memcmp_ondisk_hash(&key, node, slot, hash_len, hash)) + continue; + /* Found */ + ret = 1; + *bytenr_ret = key.offset; + *num_bytes_ret = dedupe_info->blocksize; + break; + } +out: + kfree(buf); + btrfs_free_path(path); + return ret; +} + +/* * Caller must ensure the corresponding ref head is not being run. */ static struct inmem_hash * @@ -681,9 +787,36 @@ inmem_search_hash(struct btrfs_dedupe_info *dedupe_info, u8 *hash) return NULL; } -static int inmem_search(struct btrfs_dedupe_info *dedupe_info, - struct inode *inode, u64 file_pos, - struct btrfs_dedupe_hash *hash) +/* Wapper for different backends, caller needs to hold dedupe_info->lock */ +static inline int generic_search_hash(struct btrfs_dedupe_info *dedupe_info, + u8 *hash, u64 *bytenr_ret, + u32 *num_bytes_ret) +{ + if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY) { + struct inmem_hash *found_hash; + int ret; + + found_hash = inmem_search_hash(dedupe_info, hash); + if (found_hash) { + ret = 1; + *bytenr_ret = found_hash->bytenr; + *num_bytes_ret = found_hash->num_bytes; + } else { + ret = 0; + *bytenr_ret = 0; + *num_bytes_ret = 0; + } + return ret; + } else if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_ONDISK) { + return ondisk_search_hash(dedupe_info, hash, bytenr_ret, + num_bytes_ret); + } + return -EINVAL; +} + +static int generic_search(struct btrfs_dedupe_info *dedupe_info, + struct inode *inode, u64 file_pos, + struct btrfs_dedupe_hash *hash) { int ret; struct btrfs_root *root = BTRFS_I(inode)->root; @@ -693,9 +826,9 @@ static int inmem_search(struct btrfs_dedupe_info *dedupe_info, struct btrfs_delayed_ref_head *insert_head; struct btrfs_delayed_data_ref *insert_dref; struct btrfs_qgroup_extent_record *insert_qrecord = NULL; - struct inmem_hash *found_hash; int free_insert = 1; u64 bytenr; + u64 tmp_bytenr; u32 num_bytes; insert_head = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS); @@ -727,14 +860,9 @@ static int inmem_search(struct btrfs_dedupe_info *dedupe_info, again: mutex_lock(&dedupe_info->lock); - found_hash = inmem_search_hash(dedupe_info, hash->hash); - /* If we don't find a duplicated extent, just return. */ - if (!found_hash) { - ret = 0; + ret = generic_search_hash(dedupe_info, hash->hash, &bytenr, &num_bytes); + if (ret <= 0) goto out; - } - bytenr = found_hash->bytenr; - num_bytes = found_hash->num_bytes; delayed_refs = &trans->transaction->delayed_refs; @@ -773,13 +901,17 @@ again: mutex_lock(&dedupe_info->lock); /* Search again to ensure the hash is still here */ - found_hash = inmem_search_hash(dedupe_info, hash->hash); - if (!found_hash) { - ret = 0; + ret = generic_search_hash(dedupe_info, hash->hash, &tmp_bytenr, + &num_bytes); + if (ret <= 0) { mutex_unlock(&head->mutex); goto out; } - ret = 1; + if (tmp_bytenr != bytenr) { + mutex_unlock(&head->mutex); + mutex_unlock(&dedupe_info->lock); + goto again; + } hash->bytenr = bytenr; hash->num_bytes = num_bytes; @@ -824,8 +956,9 @@ int btrfs_dedupe_search(struct btrfs_fs_info *fs_info, if (WARN_ON(btrfs_dedupe_hash_hit(hash))) return -EINVAL; - if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY) - ret = inmem_search(dedupe_info, inode, file_pos, hash); + if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY || + dedupe_info->backend == BTRFS_DEDUPE_BACKEND_ONDISK) + ret = generic_search(dedupe_info, inode, file_pos, hash); /* It's possible hash->bytenr/num_bytenr already changed */ if (ret == 0) { diff --git a/fs/btrfs/dedupe.h b/fs/btrfs/dedupe.h index 2038ab8..bfcacd7 100644 --- a/fs/btrfs/dedupe.h +++ b/fs/btrfs/dedupe.h @@ -163,6 +163,7 @@ int btrfs_dedupe_calc_hash(struct btrfs_fs_info *fs_info, * *INCREASED*, and hash->bytenr/num_bytes will record the existing * extent data. * Return 0 for a hash miss. Nothing is done + * Return < 0 for error */ int btrfs_dedupe_search(struct btrfs_fs_info *fs_info, struct inode *inode, u64 file_pos, -- 2.7.4