Now on-disk backend should be able to search hash now.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
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
--
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