#include "delayed-ref.h"
#include "locking.h"
-enum merge_mode {
- MERGE_IDENTICAL_KEYS = 1,
- MERGE_IDENTICAL_PARENTS,
-};
-
/* Just an arbitrary number so we can be sure this happened */
#define BACKREF_FOUND_SHARED 6
* this structure records all encountered refs on the way up to the root
*/
struct prelim_ref {
- struct list_head list;
+ struct rb_node rbnode;
u64 root_id;
struct btrfs_key key_for_search;
int level;
u64 wanted_disk_byte;
};
+struct preftree {
+ struct rb_root root;
+};
+
+#define PREFTREE_INIT { .root = RB_ROOT }
+
+struct preftrees {
+ struct preftree direct; /* BTRFS_SHARED_[DATA|BLOCK]_REF_KEY */
+ struct preftree indirect; /* BTRFS_[TREE_BLOCK|EXTENT_DATA]_REF_KEY */
+ struct preftree indirect_missing_keys;
+};
+
static struct kmem_cache *btrfs_prelim_ref_cache;
int __init btrfs_prelim_ref_init(void)
kmem_cache_destroy(btrfs_prelim_ref_cache);
}
+static void free_pref(struct prelim_ref *ref)
+{
+ kmem_cache_free(btrfs_prelim_ref_cache, ref);
+}
+
+/*
+ * Return 0 when both refs are for the same block (and can be merged).
+ * A -1 return indicates ref1 is a 'lower' block than ref2, while 1
+ * indicates a 'higher' block.
+ */
+static int prelim_ref_compare(struct prelim_ref *ref1,
+ struct prelim_ref *ref2)
+{
+ if (ref1->level < ref2->level)
+ return -1;
+ if (ref1->level > ref2->level)
+ return 1;
+ if (ref1->root_id < ref2->root_id)
+ return -1;
+ if (ref1->root_id > ref2->root_id)
+ return 1;
+ if (ref1->key_for_search.type < ref2->key_for_search.type)
+ return -1;
+ if (ref1->key_for_search.type > ref2->key_for_search.type)
+ return 1;
+ if (ref1->key_for_search.objectid < ref2->key_for_search.objectid)
+ return -1;
+ if (ref1->key_for_search.objectid > ref2->key_for_search.objectid)
+ return 1;
+ if (ref1->key_for_search.offset < ref2->key_for_search.offset)
+ return -1;
+ if (ref1->key_for_search.offset > ref2->key_for_search.offset)
+ return 1;
+ if (ref1->parent < ref2->parent)
+ return -1;
+ if (ref1->parent > ref2->parent)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Add @newref to the @root rbtree, merging identical refs.
+ *
+ * Callers should assumed that newref has been freed after calling.
+ */
+static void prelim_ref_insert(struct preftree *preftree,
+ struct prelim_ref *newref)
+{
+ struct rb_root *root;
+ struct rb_node **p;
+ struct rb_node *parent = NULL;
+ struct prelim_ref *ref;
+ int result;
+
+ root = &preftree->root;
+ p = &root->rb_node;
+
+ while (*p) {
+ parent = *p;
+ ref = rb_entry(parent, struct prelim_ref, rbnode);
+ result = prelim_ref_compare(ref, newref);
+ if (result < 0) {
+ p = &(*p)->rb_left;
+ } else if (result > 0) {
+ p = &(*p)->rb_right;
+ } else {
+ /* Identical refs, merge them and free @newref */
+ struct extent_inode_elem *eie = ref->inode_list;
+
+ while (eie && eie->next)
+ eie = eie->next;
+
+ if (!eie)
+ ref->inode_list = newref->inode_list;
+ else
+ eie->next = newref->inode_list;
+ ref->count += newref->count;
+ free_pref(newref);
+ return;
+ }
+ }
+
+ rb_link_node(&newref->rbnode, parent, p);
+ rb_insert_color(&newref->rbnode, root);
+}
+
+/*
+ * Release the entire tree. We don't care about internal consistency so
+ * just free everything and then reset the tree root.
+ */
+static void prelim_release(struct preftree *preftree)
+{
+ struct prelim_ref *ref, *next_ref;
+
+ rbtree_postorder_for_each_entry_safe(ref, next_ref, &preftree->root,
+ rbnode)
+ free_pref(ref);
+
+ preftree->root = RB_ROOT;
+}
+
/*
* the rules for all callers of this function are:
* - obtaining the parent is the goal
* additional information that's available but not required to find the parent
* block might help in merging entries to gain some speed.
*/
-static int add_prelim_ref(struct list_head *head, u64 root_id,
+static int add_prelim_ref(struct preftree *preftree, u64 root_id,
const struct btrfs_key *key, int level, u64 parent,
u64 wanted_disk_byte, int count, gfp_t gfp_mask)
{
ref->count = count;
ref->parent = parent;
ref->wanted_disk_byte = wanted_disk_byte;
- list_add_tail(&ref->list, head);
+ prelim_ref_insert(preftree, ref);
return 0;
}
+/* direct refs use root == 0, key == NULL */
+static int add_direct_ref(struct preftrees *preftrees, int level, u64 parent,
+ u64 wanted_disk_byte, int count, gfp_t gfp_mask)
+{
+ return add_prelim_ref(&preftrees->direct, 0, NULL, level, parent,
+ wanted_disk_byte, count, gfp_mask);
+}
+
+/* indirect refs use parent == 0 */
+static int add_indirect_ref(struct preftrees *preftrees, u64 root_id,
+ const struct btrfs_key *key, int level,
+ u64 wanted_disk_byte, int count, gfp_t gfp_mask)
+{
+ struct preftree *tree = &preftrees->indirect;
+
+ if (!key)
+ tree = &preftrees->indirect_missing_keys;
+ return add_prelim_ref(tree, root_id, key, level, 0,
+ wanted_disk_byte, count, gfp_mask);
+}
+
static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
struct ulist *parents, struct prelim_ref *ref,
int level, u64 time_seq, const u64 *extent_item_pos,
}
/*
- * resolve all indirect backrefs from the list
+ * We maintain three seperate rbtrees: one for direct refs, one for
+ * indirect refs which have a key, and one for indirect refs which do not
+ * have a key. Each tree does merge on insertion.
+ *
+ * Once all of the references are located, we iterate over the tree of
+ * indirect refs with missing keys. An appropriate key is located and
+ * the ref is moved onto the tree for indirect refs. After all missing
+ * keys are thus located, we iterate over the indirect ref tree, resolve
+ * each reference, and then insert the resolved reference onto the
+ * direct tree (merging there too).
+ *
+ * New backrefs (i.e., for parent nodes) are added to the appropriate
+ * rbtree as they are encountered. The new backrefs are subsequently
+ * resolved as above.
*/
static int resolve_indirect_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 time_seq,
- struct list_head *head,
+ struct preftrees *preftrees,
const u64 *extent_item_pos, u64 total_refs,
u64 root_objectid)
{
int err;
int ret = 0;
- struct prelim_ref *ref;
- struct prelim_ref *ref_safe;
- struct prelim_ref *new_ref;
struct ulist *parents;
struct ulist_node *node;
struct ulist_iterator uiter;
+ struct rb_node *rnode;
parents = ulist_alloc(GFP_NOFS);
if (!parents)
return -ENOMEM;
/*
- * _safe allows us to insert directly after the current item without
- * iterating over the newly inserted items.
- * we're also allowed to re-assign ref during iteration.
+ * We could trade memory usage for performance here by iterating
+ * the tree, allocating new refs for each insertion, and then
+ * freeing the entire indirect tree when we're done. In some test
+ * cases, the tree can grow quite large (~200k objects).
*/
- list_for_each_entry_safe(ref, ref_safe, head, list) {
- if (ref->parent) /* already direct */
- continue;
- if (ref->count == 0)
+ while ((rnode = rb_first(&preftrees->indirect.root))) {
+ struct prelim_ref *ref;
+
+ ref = rb_entry(rnode, struct prelim_ref, rbnode);
+ if (WARN(ref->parent,
+ "BUG: direct ref found in indirect tree")) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ rb_erase(&ref->rbnode, &preftrees->indirect.root);
+
+ if (ref->count == 0) {
+ free_pref(ref);
continue;
+ }
+
if (root_objectid && ref->root_id != root_objectid) {
+ free_pref(ref);
ret = BACKREF_FOUND_SHARED;
goto out;
}
* and return directly.
*/
if (err == -ENOENT) {
+ prelim_ref_insert(&preftrees->direct, ref);
continue;
} else if (err) {
+ free_pref(ref);
ret = err;
goto out;
}
ref->parent = node ? node->val : 0;
ref->inode_list = unode_aux_to_inode_list(node);
- /* additional parents require new refs being added here */
+ /* Add a prelim_ref(s) for any other parent(s). */
while ((node = ulist_next(parents, &uiter))) {
+ struct prelim_ref *new_ref;
+
new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
GFP_NOFS);
if (!new_ref) {
+ free_pref(ref);
ret = -ENOMEM;
goto out;
}
memcpy(new_ref, ref, sizeof(*ref));
new_ref->parent = node->val;
new_ref->inode_list = unode_aux_to_inode_list(node);
- list_add(&new_ref->list, &ref->list);
+ prelim_ref_insert(&preftrees->direct, new_ref);
}
+
+ /* Now it's a direct ref, put it in the the direct tree */
+ prelim_ref_insert(&preftrees->direct, ref);
+
ulist_reinit(parents);
}
out:
return ret;
}
-static inline int ref_for_same_block(struct prelim_ref *ref1,
- struct prelim_ref *ref2)
-{
- if (ref1->level != ref2->level)
- return 0;
- if (ref1->root_id != ref2->root_id)
- return 0;
- if (ref1->key_for_search.type != ref2->key_for_search.type)
- return 0;
- if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
- return 0;
- if (ref1->key_for_search.offset != ref2->key_for_search.offset)
- return 0;
- if (ref1->parent != ref2->parent)
- return 0;
-
- return 1;
-}
-
/*
* read tree blocks and add keys where required.
*/
static int add_missing_keys(struct btrfs_fs_info *fs_info,
- struct list_head *head)
+ struct preftrees *preftrees)
{
struct prelim_ref *ref;
struct extent_buffer *eb;
+ struct preftree *tree = &preftrees->indirect_missing_keys;
+ struct rb_node *node;
- list_for_each_entry(ref, head, list) {
- if (ref->parent)
- continue;
- if (ref->key_for_search.type)
- continue;
+ while ((node = rb_first(&tree->root))) {
+ ref = rb_entry(node, struct prelim_ref, rbnode);
+ rb_erase(node, &tree->root);
+
+ BUG_ON(ref->parent); /* should not be a direct ref */
+ BUG_ON(ref->key_for_search.type);
BUG_ON(!ref->wanted_disk_byte);
+
eb = read_tree_block(fs_info, ref->wanted_disk_byte, 0);
if (IS_ERR(eb)) {
+ free_pref(ref);
return PTR_ERR(eb);
} else if (!extent_buffer_uptodate(eb)) {
+ free_pref(ref);
free_extent_buffer(eb);
return -EIO;
}
btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
+ prelim_ref_insert(&preftrees->indirect, ref);
}
return 0;
}
-/*
- * merge backrefs and adjust counts accordingly
- *
- * FIXME: For MERGE_IDENTICAL_KEYS, if we add more keys in add_prelim_ref
- * then we can merge more here. Additionally, we could even add a key
- * range for the blocks we looked into to merge even more (-> replace
- * unresolved refs by those having a parent).
- */
-static void merge_refs(struct list_head *head, enum merge_mode mode)
-{
- struct prelim_ref *pos1;
-
- list_for_each_entry(pos1, head, list) {
- struct prelim_ref *pos2 = pos1, *tmp;
-
- list_for_each_entry_safe_continue(pos2, tmp, head, list) {
- struct prelim_ref *ref1 = pos1, *ref2 = pos2;
- struct extent_inode_elem *eie;
-
- if (!ref_for_same_block(ref1, ref2))
- continue;
- if (mode == MERGE_IDENTICAL_KEYS) {
- if (!ref1->parent && ref2->parent)
- swap(ref1, ref2);
- } else {
- if (ref1->parent != ref2->parent)
- continue;
- }
-
- eie = ref1->inode_list;
- while (eie && eie->next)
- eie = eie->next;
- if (eie)
- eie->next = ref2->inode_list;
- else
- ref1->inode_list = ref2->inode_list;
- ref1->count += ref2->count;
-
- list_del(&ref2->list);
- kmem_cache_free(btrfs_prelim_ref_cache, ref2);
- cond_resched();
- }
-
- }
-}
-
/*
* add all currently queued delayed refs from this head whose seq nr is
* smaller or equal that seq to the list
*/
static int add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
- struct list_head *prefs, u64 *total_refs,
+ struct preftrees *preftrees, u64 *total_refs,
u64 inum)
{
struct btrfs_delayed_ref_node *node;
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
struct btrfs_key key;
- struct btrfs_key op_key = {0};
+ struct btrfs_key tmp_op_key;
+ struct btrfs_key *op_key = NULL;
int sgn;
int ret = 0;
- if (extent_op && extent_op->update_key)
- btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
+ if (extent_op && extent_op->update_key) {
+ btrfs_disk_key_to_cpu(&tmp_op_key, &extent_op->key);
+ op_key = &tmp_op_key;
+ }
spin_lock(&head->lock);
list_for_each_entry(node, &head->ref_list, list) {
*total_refs += (node->ref_mod * sgn);
switch (node->type) {
case BTRFS_TREE_BLOCK_REF_KEY: {
+ /* NORMAL INDIRECT METADATA backref */
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
- ret = add_prelim_ref(prefs, ref->root, &op_key,
- ref->level + 1, 0, node->bytenr,
- node->ref_mod * sgn, GFP_ATOMIC);
+ ret = add_indirect_ref(preftrees, ref->root, &tmp_op_key,
+ ref->level + 1, node->bytenr,
+ node->ref_mod * sgn,
+ GFP_ATOMIC);
break;
}
case BTRFS_SHARED_BLOCK_REF_KEY: {
+ /* SHARED DIRECT METADATA backref */
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
- ret = add_prelim_ref(prefs, 0, NULL, ref->level + 1,
+
+ ret = add_direct_ref(preftrees, ref->level + 1,
ref->parent, node->bytenr,
- node->ref_mod * sgn, GFP_ATOMIC);
+ node->ref_mod * sgn,
+ GFP_ATOMIC);
break;
}
case BTRFS_EXTENT_DATA_REF_KEY: {
+ /* NORMAL INDIRECT DATA backref */
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
break;
}
- ret = add_prelim_ref(prefs, ref->root, &key, 0, 0,
- node->bytenr, node->ref_mod * sgn,
- GFP_ATOMIC);
+ ret = add_indirect_ref(preftrees, ref->root, &key, 0,
+ node->bytenr,
+ node->ref_mod * sgn,
+ GFP_ATOMIC);
break;
}
case BTRFS_SHARED_DATA_REF_KEY: {
+ /* SHARED DIRECT FULL backref */
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
- ret = add_prelim_ref(prefs, 0, NULL, 0, ref->parent,
- node->bytenr, node->ref_mod * sgn,
+
+ ret = add_direct_ref(preftrees, 0, ref->parent,
+ node->bytenr,
+ node->ref_mod * sgn,
GFP_ATOMIC);
break;
}
* add all inline backrefs for bytenr to the list
*/
static int add_inline_refs(struct btrfs_path *path, u64 bytenr,
- int *info_level, struct list_head *prefs,
+ int *info_level, struct preftrees *preftrees,
u64 *total_refs, u64 inum)
{
int ret = 0;
switch (type) {
case BTRFS_SHARED_BLOCK_REF_KEY:
- ret = add_prelim_ref(prefs, 0, NULL, *info_level + 1,
- offset, bytenr, 1, GFP_NOFS);
+ ret = add_direct_ref(preftrees, *info_level + 1, offset,
+ bytenr, 1, GFP_NOFS);
break;
case BTRFS_SHARED_DATA_REF_KEY: {
struct btrfs_shared_data_ref *sdref;
sdref = (struct btrfs_shared_data_ref *)(iref + 1);
count = btrfs_shared_data_ref_count(leaf, sdref);
- ret = add_prelim_ref(prefs, 0, NULL, 0, offset,
+
+ ret = add_direct_ref(preftrees, 0, offset,
bytenr, count, GFP_NOFS);
break;
}
case BTRFS_TREE_BLOCK_REF_KEY:
- ret = add_prelim_ref(prefs, offset, NULL,
- *info_level + 1, 0,
- bytenr, 1, GFP_NOFS);
+ ret = add_indirect_ref(preftrees, offset, NULL,
+ *info_level + 1, bytenr, 1,
+ GFP_NOFS);
break;
case BTRFS_EXTENT_DATA_REF_KEY: {
struct btrfs_extent_data_ref *dref;
}
root = btrfs_extent_data_ref_root(leaf, dref);
- ret = add_prelim_ref(prefs, root, &key, 0, 0,
- bytenr, count, GFP_NOFS);
+
+ ret = add_indirect_ref(preftrees, root, &key, 0, bytenr,
+ count, GFP_NOFS);
break;
}
default:
*/
static int add_keyed_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 bytenr,
- int info_level, struct list_head *prefs, u64 inum)
+ int info_level, struct preftrees *preftrees,
+ u64 inum)
{
struct btrfs_root *extent_root = fs_info->extent_root;
int ret;
switch (key.type) {
case BTRFS_SHARED_BLOCK_REF_KEY:
- ret = add_prelim_ref(prefs, 0, NULL, info_level + 1,
- key.offset, bytenr, 1, GFP_NOFS);
+ /* SHARED DIRECT METADATA backref */
+ ret = add_direct_ref(preftrees, info_level + 1,
+ key.offset, bytenr, 1,
+ GFP_NOFS);
break;
case BTRFS_SHARED_DATA_REF_KEY: {
+ /* SHARED DIRECT FULL backref */
struct btrfs_shared_data_ref *sdref;
int count;
sdref = btrfs_item_ptr(leaf, slot,
struct btrfs_shared_data_ref);
count = btrfs_shared_data_ref_count(leaf, sdref);
- ret = add_prelim_ref(prefs, 0, NULL, 0, key.offset,
- bytenr, count, GFP_NOFS);
+ ret = add_direct_ref(preftrees, 0, key.offset, bytenr,
+ count, GFP_NOFS);
break;
}
case BTRFS_TREE_BLOCK_REF_KEY:
- ret = add_prelim_ref(prefs, key.offset, NULL,
- info_level + 1, 0,
- bytenr, 1, GFP_NOFS);
+ /* NORMAL INDIRECT METADATA backref */
+ ret = add_indirect_ref(preftrees, key.offset, NULL,
+ info_level + 1, bytenr, 1,
+ GFP_NOFS);
break;
case BTRFS_EXTENT_DATA_REF_KEY: {
+ /* NORMAL INDIRECT DATA backref */
struct btrfs_extent_data_ref *dref;
int count;
u64 root;
}
root = btrfs_extent_data_ref_root(leaf, dref);
- ret = add_prelim_ref(prefs, root, &key, 0, 0,
- bytenr, count, GFP_NOFS);
+ ret = add_indirect_ref(preftrees, root, &key, 0, bytenr,
+ count, GFP_NOFS);
break;
}
default:
struct btrfs_delayed_ref_head *head;
int info_level = 0;
int ret;
- struct list_head prefs_delayed;
- struct list_head prefs;
struct prelim_ref *ref;
+ struct rb_node *node;
struct extent_inode_elem *eie = NULL;
+ /* total of both direct AND indirect refs! */
u64 total_refs = 0;
-
- INIT_LIST_HEAD(&prefs);
- INIT_LIST_HEAD(&prefs_delayed);
+ struct preftrees preftrees = {
+ .direct = PREFTREE_INIT,
+ .indirect = PREFTREE_INIT,
+ .indirect_missing_keys = PREFTREE_INIT
+ };
key.objectid = bytenr;
key.offset = (u64)-1;
goto again;
}
spin_unlock(&delayed_refs->lock);
- ret = add_delayed_refs(head, time_seq,
- &prefs_delayed, &total_refs,
- inum);
+ ret = add_delayed_refs(head, time_seq, &preftrees,
+ &total_refs, inum);
mutex_unlock(&head->mutex);
if (ret)
goto out;
(key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY)) {
ret = add_inline_refs(path, bytenr, &info_level,
- &prefs, &total_refs, inum);
+ &preftrees, &total_refs, inum);
if (ret)
goto out;
ret = add_keyed_refs(fs_info, path, bytenr, info_level,
- &prefs, inum);
+ &preftrees, inum);
if (ret)
goto out;
}
}
- btrfs_release_path(path);
- list_splice_init(&prefs_delayed, &prefs);
+ btrfs_release_path(path);
- ret = add_missing_keys(fs_info, &prefs);
+ ret = add_missing_keys(fs_info, &preftrees);
if (ret)
goto out;
- merge_refs(&prefs, MERGE_IDENTICAL_KEYS);
+ WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect_missing_keys.root));
- ret = resolve_indirect_refs(fs_info, path, time_seq, &prefs,
+ ret = resolve_indirect_refs(fs_info, path, time_seq, &preftrees,
extent_item_pos, total_refs,
root_objectid);
if (ret)
goto out;
- merge_refs(&prefs, MERGE_IDENTICAL_PARENTS);
+ WARN_ON(!RB_EMPTY_ROOT(&preftrees.indirect.root));
- while (!list_empty(&prefs)) {
- ref = list_first_entry(&prefs, struct prelim_ref, list);
+ /*
+ * This walks the tree of merged and resolved refs. Tree blocks are
+ * read in as needed. Unique entries are added to the ulist, and
+ * the list of found roots is updated.
+ *
+ * We release the entire tree in one go before returning.
+ */
+ node = rb_first(&preftrees.direct.root);
+ while (node) {
+ ref = rb_entry(node, struct prelim_ref, rbnode);
+ node = rb_next(&ref->rbnode);
WARN_ON(ref->count < 0);
if (roots && ref->count && ref->root_id && ref->parent == 0) {
if (root_objectid && ref->root_id != root_objectid) {
}
eie = NULL;
}
- list_del(&ref->list);
- kmem_cache_free(btrfs_prelim_ref_cache, ref);
}
out:
btrfs_free_path(path);
- while (!list_empty(&prefs)) {
- ref = list_first_entry(&prefs, struct prelim_ref, list);
- list_del(&ref->list);
- kmem_cache_free(btrfs_prelim_ref_cache, ref);
- }
- while (!list_empty(&prefs_delayed)) {
- ref = list_first_entry(&prefs_delayed, struct prelim_ref,
- list);
- list_del(&ref->list);
- kmem_cache_free(btrfs_prelim_ref_cache, ref);
- }
+
+ prelim_release(&preftrees.direct);
+ prelim_release(&preftrees.indirect);
+ prelim_release(&preftrees.indirect_missing_keys);
+
if (ret < 0)
free_inode_elem_list(eie);
return ret;
projects / users / jedix / linux-maple.git / commitdiff