From: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
To: <linux-btrfs@vger.kernel.org>
Cc: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>,
Mark Fasheh <mfasheh@suse.de>,
Qu Wenruo <quwenruo@cn.fujitsu.com>
Subject: [PATCH v15.1 04/13] btrfs: dedupe: Introduce function to remove hash from in-memory tree
Date: Tue, 6 Nov 2018 14:41:13 +0800 [thread overview]
Message-ID: <20181106064122.6154-5-lufq.fnst@cn.fujitsu.com> (raw)
In-Reply-To: <20181106064122.6154-1-lufq.fnst@cn.fujitsu.com>
From: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Introduce static function inmem_del() to remove hash from in-memory
dedupe tree.
And implement btrfs_dedupe_del() and btrfs_dedup_disable() interfaces.
Also for btrfs_dedupe_disable(), add new functions to wait existing
writer and block incoming writers to eliminate all possible race.
Cc: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
---
fs/btrfs/dedupe.c | 131 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 125 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/dedupe.c b/fs/btrfs/dedupe.c
index 784bb3a8a5ab..951fefd19fde 100644
--- a/fs/btrfs/dedupe.c
+++ b/fs/btrfs/dedupe.c
@@ -170,12 +170,6 @@ int btrfs_dedupe_enable(struct btrfs_fs_info *fs_info,
return ret;
}
-int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
-{
- /* Place holder for bisect, will be implemented in later patches */
- return 0;
-}
-
static int inmem_insert_hash(struct rb_root *root,
struct inmem_hash *hash, int hash_len)
{
@@ -317,3 +311,128 @@ int btrfs_dedupe_add(struct btrfs_fs_info *fs_info,
return inmem_add(dedupe_info, hash);
return -EINVAL;
}
+
+static struct inmem_hash *
+inmem_search_bytenr(struct btrfs_dedupe_info *dedupe_info, u64 bytenr)
+{
+ struct rb_node **p = &dedupe_info->bytenr_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 (bytenr < entry->bytenr)
+ p = &(*p)->rb_left;
+ else if (bytenr > entry->bytenr)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ return NULL;
+}
+
+/* Delete a hash from in-memory dedupe tree */
+static int inmem_del(struct btrfs_dedupe_info *dedupe_info, u64 bytenr)
+{
+ struct inmem_hash *hash;
+
+ mutex_lock(&dedupe_info->lock);
+ hash = inmem_search_bytenr(dedupe_info, bytenr);
+ if (!hash) {
+ mutex_unlock(&dedupe_info->lock);
+ return 0;
+ }
+
+ __inmem_del(dedupe_info, hash);
+ mutex_unlock(&dedupe_info->lock);
+ return 0;
+}
+
+/* Remove a dedupe hash from dedupe tree */
+int btrfs_dedupe_del(struct btrfs_fs_info *fs_info, u64 bytenr)
+{
+ struct btrfs_dedupe_info *dedupe_info = fs_info->dedupe_info;
+
+ if (!fs_info->dedupe_enabled)
+ return 0;
+
+ if (WARN_ON(dedupe_info == NULL))
+ return -EINVAL;
+
+ if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
+ return inmem_del(dedupe_info, bytenr);
+ return -EINVAL;
+}
+
+static void inmem_destroy(struct btrfs_dedupe_info *dedupe_info)
+{
+ struct inmem_hash *entry, *tmp;
+
+ mutex_lock(&dedupe_info->lock);
+ list_for_each_entry_safe(entry, tmp, &dedupe_info->lru_list, lru_list)
+ __inmem_del(dedupe_info, entry);
+ mutex_unlock(&dedupe_info->lock);
+}
+
+/*
+ * Helper function to wait and block all incoming writers
+ *
+ * Use rw_sem introduced for freeze to wait/block writers.
+ * So during the block time, no new write will happen, so we can
+ * do something quite safe, espcially helpful for dedupe disable,
+ * as it affect buffered write.
+ */
+static void block_all_writers(struct btrfs_fs_info *fs_info)
+{
+ struct super_block *sb = fs_info->sb;
+
+ percpu_down_write(sb->s_writers.rw_sem + SB_FREEZE_WRITE - 1);
+ down_write(&sb->s_umount);
+}
+
+static void unblock_all_writers(struct btrfs_fs_info *fs_info)
+{
+ struct super_block *sb = fs_info->sb;
+
+ up_write(&sb->s_umount);
+ percpu_up_write(sb->s_writers.rw_sem + SB_FREEZE_WRITE - 1);
+}
+
+int btrfs_dedupe_disable(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_dedupe_info *dedupe_info;
+ int ret;
+
+ dedupe_info = fs_info->dedupe_info;
+
+ if (!dedupe_info)
+ return 0;
+
+ /* Don't allow disable status change in RO mount */
+ if (fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
+
+ /*
+ * Wait for all unfinished writers and block further writers.
+ * Then sync the whole fs so all current write will go through
+ * dedupe, and all later write won't go through dedupe.
+ */
+ block_all_writers(fs_info);
+ ret = sync_filesystem(fs_info->sb);
+ fs_info->dedupe_enabled = 0;
+ fs_info->dedupe_info = NULL;
+ unblock_all_writers(fs_info);
+ if (ret < 0)
+ return ret;
+
+ /* now we are OK to clean up everything */
+ if (dedupe_info->backend == BTRFS_DEDUPE_BACKEND_INMEMORY)
+ inmem_destroy(dedupe_info);
+
+ crypto_free_shash(dedupe_info->dedupe_driver);
+ kfree(dedupe_info);
+ return 0;
+}
--
2.19.1
next prev parent reply other threads:[~2018-11-06 6:41 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 6:41 [PATCH v15.1 00/13] Btrfs In-band De-duplication Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 01/13] btrfs: dedupe: Introduce dedupe framework and its header Lu Fengqi
2018-11-08 9:53 ` Timofey Titovets
2018-11-09 21:10 ` Josef Bacik
2018-11-06 6:41 ` [PATCH v15.1 02/13] btrfs: dedupe: Introduce function to initialize dedupe info Lu Fengqi
2018-11-08 12:31 ` Timofey Titovets
2018-11-06 6:41 ` [PATCH v15.1 03/13] btrfs: dedupe: Introduce function to add hash into in-memory tree Lu Fengqi
2018-11-08 20:18 ` Timofey Titovets
2018-11-06 6:41 ` Lu Fengqi [this message]
2018-11-09 21:17 ` [PATCH v15.1 04/13] btrfs: dedupe: Introduce function to remove hash from " Josef Bacik
2018-11-06 6:41 ` [PATCH v15.1 05/13] btrfs: delayed-ref: Add support for increasing data ref under spinlock Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 06/13] btrfs: dedupe: Introduce function to search for an existing hash Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 07/13] btrfs: dedupe: Implement btrfs_dedupe_calc_hash interface Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 08/13] btrfs: ordered-extent: Add support for dedupe Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 09/13] btrfs: introduce type based delalloc metadata reserve Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 10/13] btrfs: dedupe: Inband in-memory only de-duplication implement Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 11/13] btrfs: dedupe: Add ioctl for inband deduplication Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 12/13] btrfs: relocation: Enhance error handling to avoid BUG_ON Lu Fengqi
2018-11-06 6:41 ` [PATCH v15.1 13/13] btrfs: dedupe: Introduce new reconfigure ioctl Lu Fengqi
2018-11-10 7:21 ` [PATCH v15.1 00/13] Btrfs In-band De-duplication Anand Jain
2018-11-13 13:45 ` David Sterba
2018-11-14 3:47 ` Lu Fengqi
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