@@ -482,6 +482,79 @@ int btrfs_dedup_disable(struct btrfs_fs_info *fs_info)
}
/*
+ * Return 0 for not found
+ * Return >0 for found and set bytenr_ret
+ * Return <0 for error
+ */
+static int ondisk_search_hash(struct btrfs_dedup_info *dedup_info, u8 *hash,
+ u64 *bytenr_ret, u32 *num_bytes_ret)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_root *dedup_root = dedup_info->dedup_root;
+ u8 *buf = NULL;
+ u64 hash_key;
+ int hash_len = btrfs_dedup_sizes[dedup_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_DEDUP_HASH_ITEM_KEY;
+ key.offset = (u64)-1;
+
+ ret = btrfs_search_slot(NULL, dedup_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ WARN_ON(ret == 0);
+ while (1) {
+ struct extent_buffer *node;
+ struct btrfs_dedup_hash_item *hash_item;
+ int slot;
+
+ ret = btrfs_previous_item(dedup_root, path, hash_key,
+ BTRFS_DEDUP_HASH_ITEM_KEY);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = 0;
+ goto out;
+ }
+
+ node = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(node, &key, slot);
+
+ if (key.type != BTRFS_DEDUP_HASH_ITEM_KEY ||
+ memcmp(&key.objectid, hash + hash_len - 8, 8))
+ break;
+ hash_item = btrfs_item_ptr(node, slot,
+ struct btrfs_dedup_hash_item);
+ read_extent_buffer(node, buf, (unsigned long)(hash_item + 1),
+ hash_len);
+ if (!memcmp(buf, hash, hash_len)) {
+ ret = 1;
+ *bytenr_ret = key.offset;
+ *num_bytes_ret = btrfs_dedup_hash_len(node, hash_item);
+ 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 *
@@ -511,7 +584,34 @@ inmem_search_hash(struct btrfs_dedup_info *dedup_info, u8 *hash)
return NULL;
}
-static int inmem_search(struct inode *inode, u64 file_pos,
+/* Wrapper for different backends, caller needs to hold dedup_info->lock */
+static inline int generic_search_hash(struct btrfs_dedup_info *dedup_info,
+ u8 *hash, u64 *bytenr_ret,
+ u32 *num_bytes_ret)
+{
+ if (dedup_info->hash_type == BTRFS_DEDUP_BACKEND_INMEMORY) {
+ struct inmem_hash *found_hash;
+ int ret;
+
+ found_hash = inmem_search_hash(dedup_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 (dedup_info->hash_type == BTRFS_DEDUP_BACKEND_ONDISK) {
+ return ondisk_search_hash(dedup_info, hash, bytenr_ret,
+ num_bytes_ret);
+ }
+ return -EINVAL;
+}
+
+static int generic_search(struct inode *inode, u64 file_pos,
struct btrfs_dedup_hash *hash)
{
int ret;
@@ -520,9 +620,9 @@ static int inmem_search(struct inode *inode, u64 file_pos,
struct btrfs_trans_handle *trans;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *head;
- struct inmem_hash *found_hash;
struct btrfs_dedup_info *dedup_info = fs_info->dedup_info;
u64 bytenr;
+ u64 tmp_bytenr;
u32 num_bytes;
trans = btrfs_join_transaction(root);
@@ -531,14 +631,9 @@ static int inmem_search(struct inode *inode, u64 file_pos,
again:
mutex_lock(&dedup_info->lock);
- found_hash = inmem_search_hash(dedup_info, hash->hash);
- /* If we don't find a duplicated extent, just return. */
- if (!found_hash) {
- ret = 0;
+ ret = generic_search_hash(dedup_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;
@@ -574,13 +669,21 @@ again:
goto again;
mutex_lock(&dedup_info->lock);
- /* Search again to ensure the hash is still here */
- found_hash = inmem_search_hash(dedup_info, hash->hash);
- if (!found_hash) {
- ret = 0;
+ /*
+ * Search again to ensure the hash is still here and bytenr didn't
+ * change
+ */
+ ret = generic_search_hash(dedup_info, hash->hash, &tmp_bytenr,
+ &num_bytes);
+ if (ret <= 0) {
mutex_unlock(&head->mutex);
goto out;
}
+ if (tmp_bytenr != bytenr) {
+ mutex_unlock(&head->mutex);
+ mutex_unlock(&dedup_info->lock);
+ goto again;
+ }
hash->bytenr = bytenr;
hash->num_bytes = num_bytes;
@@ -609,15 +712,15 @@ int btrfs_dedup_search(struct inode *inode, u64 file_pos,
if (WARN_ON(!dedup_info || !hash))
return 0;
- if (dedup_info->backend == BTRFS_DEDUP_BACKEND_INMEMORY)
- ret = inmem_search(inode, file_pos, hash);
-
- /* It's possible hash->bytenr/num_bytenr already changed */
- if (ret == 0) {
- hash->num_bytes = 0;
- hash->bytenr = 0;
+ if (dedup_info->backend < BTRFS_DEDUP_BACKEND_LAST) {
+ ret = generic_search(inode, file_pos, hash);
+ if (ret == 0) {
+ hash->num_bytes = 0;
+ hash->bytenr = 0;
+ }
+ return ret;
}
- return ret;
+ return -EINVAL;
}
static int hash_data(struct btrfs_dedup_info *dedup_info, const char *data,
@@ -137,6 +137,9 @@ int btrfs_dedup_calc_hash(struct btrfs_root *root, struct inode *inode,
* *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.
+ *
+ * Only on-disk backedn may return error though.
*/
int btrfs_dedup_search(struct inode *inode, u64 file_pos,
struct btrfs_dedup_hash *hash);