From: Jan Kara Subject: Re: [PATCH 23/28] mbcache: make mbcache more generic Date: Thu, 15 Jun 2017 09:41:58 +0200 Message-ID: <20170615074158.GA1764@quack2.suse.cz> References: <20170531081517.11438-1-tahsin@google.com> <20170531081517.11438-23-tahsin@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Theodore Ts'o , Andreas Dilger , Dave Kleikamp , Alexander Viro , Mark Fasheh , Joel Becker , Jens Axboe , Deepa Dinamani , Mike Christie , Fabian Frederick , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, jfs-discussion@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org To: Tahsin Erdogan Return-path: Content-Disposition: inline In-Reply-To: <20170531081517.11438-23-tahsin@google.com> Sender: reiserfs-devel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed 31-05-17 01:15:12, Tahsin Erdogan wrote: > Large xattr feature would like to use the mbcache for xattr value > deduplication. Current implementation is geared towards xattr block > deduplication. Make it more generic so that it can be used by both. Can you explain a bit more what do you mean by "make it more generic" as it seems you just rename a couple of things here... Honza > > Signed-off-by: Tahsin Erdogan > --- > fs/ext2/xattr.c | 18 +++++++++--------- > fs/ext4/xattr.c | 10 +++++----- > fs/mbcache.c | 43 +++++++++++++++++++++---------------------- > include/linux/mbcache.h | 14 ++++++++------ > 4 files changed, 43 insertions(+), 42 deletions(-) > > diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c > index fbdb8f171893..1e5f76070580 100644 > --- a/fs/ext2/xattr.c > +++ b/fs/ext2/xattr.c > @@ -493,8 +493,8 @@ bad_block: ext2_error(sb, "ext2_xattr_set", > * This must happen under buffer lock for > * ext2_xattr_set2() to reliably detect modified block > */ > - mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache, > - hash, bh->b_blocknr); > + mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash, > + bh->b_blocknr); > > /* keep the buffer locked while modifying it. */ > } else { > @@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, > * This must happen under buffer lock for > * ext2_xattr_set2() to reliably detect freed block > */ > - mb_cache_entry_delete_block(ext2_mb_cache, > - hash, old_bh->b_blocknr); > + mb_cache_entry_delete(ext2_mb_cache, hash, > + old_bh->b_blocknr); > /* Free the old block. */ > ea_bdebug(old_bh, "freeing"); > ext2_free_blocks(inode, old_bh->b_blocknr, 1); > @@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode) > * This must happen under buffer lock for ext2_xattr_set2() to > * reliably detect freed block > */ > - mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache, > - hash, bh->b_blocknr); > + mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash, > + bh->b_blocknr); > ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); > get_bh(bh); > bforget(bh); > @@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) > while (ce) { > struct buffer_head *bh; > > - bh = sb_bread(inode->i_sb, ce->e_block); > + bh = sb_bread(inode->i_sb, ce->e_value); > if (!bh) { > ext2_error(inode->i_sb, "ext2_xattr_cache_find", > "inode %ld: block %ld read error", > - inode->i_ino, (unsigned long) ce->e_block); > + inode->i_ino, (unsigned long) ce->e_value); > } else { > lock_buffer(bh); > /* > @@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) > } else if (le32_to_cpu(HDR(bh)->h_refcount) > > EXT2_XATTR_REFCOUNT_MAX) { > ea_idebug(inode, "block %ld refcount %d>%d", > - (unsigned long) ce->e_block, > + (unsigned long) ce->e_value, > le32_to_cpu(HDR(bh)->h_refcount), > EXT2_XATTR_REFCOUNT_MAX); > } else if (!ext2_xattr_cmp(header, HDR(bh))) { > diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c > index 886d06e409b6..772948f168c3 100644 > --- a/fs/ext4/xattr.c > +++ b/fs/ext4/xattr.c > @@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode, > * This must happen under buffer lock for > * ext4_xattr_block_set() to reliably detect freed block > */ > - mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr); > + mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr); > get_bh(bh); > unlock_buffer(bh); > ext4_free_blocks(handle, inode, bh, 0, 1, > @@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode, > * ext4_xattr_block_set() to reliably detect modified > * block > */ > - mb_cache_entry_delete_block(ext4_mb_cache, hash, > - bs->bh->b_blocknr); > + mb_cache_entry_delete(ext4_mb_cache, hash, > + bs->bh->b_blocknr); > ea_bdebug(bs->bh, "modifying in-place"); > error = ext4_xattr_set_entry(i, s, handle, inode); > if (!error) { > @@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, > while (ce) { > struct buffer_head *bh; > > - bh = sb_bread(inode->i_sb, ce->e_block); > + bh = sb_bread(inode->i_sb, ce->e_value); > if (!bh) { > EXT4_ERROR_INODE(inode, "block %lu read error", > - (unsigned long) ce->e_block); > + (unsigned long) ce->e_value); > } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { > *pce = ce; > return bh; > diff --git a/fs/mbcache.c b/fs/mbcache.c > index b19be429d655..77a5b99d8f92 100644 > --- a/fs/mbcache.c > +++ b/fs/mbcache.c > @@ -10,7 +10,7 @@ > /* > * Mbcache is a simple key-value store. Keys need not be unique, however > * key-value pairs are expected to be unique (we use this fact in > - * mb_cache_entry_delete_block()). > + * mb_cache_entry_delete()). > * > * Ext2 and ext4 use this cache for deduplication of extended attribute blocks. > * They use hash of a block contents as a key and block number as a value. > @@ -62,15 +62,15 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache, > * @cache - cache where the entry should be created > * @mask - gfp mask with which the entry should be allocated > * @key - key of the entry > - * @block - block that contains data > - * @reusable - is the block reusable by other inodes? > + * @value - value of the entry > + * @reusable - is the entry reusable by others? > * > - * Creates entry in @cache with key @key and records that data is stored in > - * block @block. The function returns -EBUSY if entry with the same key > - * and for the same block already exists in cache. Otherwise 0 is returned. > + * Creates entry in @cache with key @key and value @value. The function returns > + * -EBUSY if entry with the same key and value already exists in cache. > + * Otherwise 0 is returned. > */ > int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, > - sector_t block, bool reusable) > + cache_value_t value, bool reusable) > { > struct mb_cache_entry *entry, *dup; > struct hlist_bl_node *dup_node; > @@ -91,12 +91,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, > /* One ref for hash, one ref returned */ > atomic_set(&entry->e_refcnt, 1); > entry->e_key = key; > - entry->e_block = block; > + entry->e_value = value; > entry->e_reusable = reusable; > head = mb_cache_entry_head(cache, key); > hlist_bl_lock(head); > hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) { > - if (dup->e_key == key && dup->e_block == block) { > + if (dup->e_key == key && dup->e_value == value) { > hlist_bl_unlock(head); > kmem_cache_free(mb_entry_cache, entry); > return -EBUSY; > @@ -187,13 +187,13 @@ struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, > EXPORT_SYMBOL(mb_cache_entry_find_next); > > /* > - * mb_cache_entry_get - get a cache entry by block number (and key) > + * mb_cache_entry_get - get a cache entry by value (and key) > * @cache - cache we work with > - * @key - key of block number @block > - * @block - block number > + * @key - key > + * @value - value > */ > struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, > - sector_t block) > + cache_value_t value) > { > struct hlist_bl_node *node; > struct hlist_bl_head *head; > @@ -202,7 +202,7 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, > head = mb_cache_entry_head(cache, key); > hlist_bl_lock(head); > hlist_bl_for_each_entry(entry, node, head, e_hash_list) { > - if (entry->e_key == key && entry->e_block == block) { > + if (entry->e_key == key && entry->e_value == value) { > atomic_inc(&entry->e_refcnt); > goto out; > } > @@ -214,15 +214,14 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, > } > EXPORT_SYMBOL(mb_cache_entry_get); > > -/* mb_cache_entry_delete_block - remove information about block from cache > +/* mb_cache_entry_delete - remove a cache entry > * @cache - cache we work with > - * @key - key of block @block > - * @block - block number > + * @key - key > + * @value - value > * > - * Remove entry from cache @cache with key @key with data stored in @block. > + * Remove entry from cache @cache with key @key and value @value. > */ > -void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, > - sector_t block) > +void mb_cache_entry_delete(struct mb_cache *cache, u32 key, cache_value_t value) > { > struct hlist_bl_node *node; > struct hlist_bl_head *head; > @@ -231,7 +230,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, > head = mb_cache_entry_head(cache, key); > hlist_bl_lock(head); > hlist_bl_for_each_entry(entry, node, head, e_hash_list) { > - if (entry->e_key == key && entry->e_block == block) { > + if (entry->e_key == key && entry->e_value == value) { > /* We keep hash list reference to keep entry alive */ > hlist_bl_del_init(&entry->e_hash_list); > hlist_bl_unlock(head); > @@ -248,7 +247,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, > } > hlist_bl_unlock(head); > } > -EXPORT_SYMBOL(mb_cache_entry_delete_block); > +EXPORT_SYMBOL(mb_cache_entry_delete); > > /* mb_cache_entry_touch - cache entry got used > * @cache - cache the entry belongs to > diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h > index 86c9a8b480c5..e2d9f2f926a4 100644 > --- a/include/linux/mbcache.h > +++ b/include/linux/mbcache.h > @@ -9,6 +9,8 @@ > > struct mb_cache; > > +typedef sector_t cache_value_t; > + > struct mb_cache_entry { > /* List of entries in cache - protected by cache->c_list_lock */ > struct list_head e_list; > @@ -19,15 +21,15 @@ struct mb_cache_entry { > u32 e_key; > u32 e_referenced:1; > u32 e_reusable:1; > - /* Block number of hashed block - stable during lifetime of the entry */ > - sector_t e_block; > + /* User provided value - stable during lifetime of the entry */ > + cache_value_t e_value; > }; > > struct mb_cache *mb_cache_create(int bucket_bits); > void mb_cache_destroy(struct mb_cache *cache); > > int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, > - sector_t block, bool reusable); > + cache_value_t value, bool reusable); > void __mb_cache_entry_free(struct mb_cache_entry *entry); > static inline int mb_cache_entry_put(struct mb_cache *cache, > struct mb_cache_entry *entry) > @@ -38,10 +40,10 @@ static inline int mb_cache_entry_put(struct mb_cache *cache, > return 1; > } > > -void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, > - sector_t block); > +void mb_cache_entry_delete(struct mb_cache *cache, u32 key, > + cache_value_t value); > struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key, > - sector_t block); > + cache_value_t value); > struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache, > u32 key); > struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache, > -- > 2.13.0.219.gdb65acc882-goog > > -- Jan Kara SUSE Labs, CR