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btrfs: backref: rename and move handle_one_tree_block() 

This function is the major part of backref cache build process, move it
to backref.c so we can reuse it later.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo 2020-03-23 16:08:34 +08:00 committed by David Sterba
parent d36e7f0e8f
commit 1b60d2ec98
3 changed files with 373 additions and 355 deletions
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365
fs/btrfs/backref.c
View File

@ -13,6 +13,7 @@
#include "transaction.h"
#include "delayed-ref.h"
#include "locking.h"
#include "misc.h"
/* Just an arbitrary number so we can be sure this happened */
#define BACKREF_FOUND_SHARED 6
@ -2592,3 +2593,367 @@ void btrfs_backref_release_cache(struct btrfs_backref_cache *cache)
ASSERT(!cache->nr_nodes);
ASSERT(!cache->nr_edges);
}
/*
* Handle direct tree backref
*
* Direct tree backref means, the backref item shows its parent bytenr
* directly. This is for SHARED_BLOCK_REF backref (keyed or inlined).
*
* @ref_key: The converted backref key.
* For keyed backref, it's the item key.
* For inlined backref, objectid is the bytenr,
* type is btrfs_inline_ref_type, offset is
* btrfs_inline_ref_offset.
*/
static int handle_direct_tree_backref(struct btrfs_backref_cache *cache,
struct btrfs_key *ref_key,
struct btrfs_backref_node *cur)
{
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *upper;
struct rb_node *rb_node;
ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY);
/* Only reloc root uses backref pointing to itself */
if (ref_key->objectid == ref_key->offset) {
struct btrfs_root *root;
cur->is_reloc_root = 1;
/* Only reloc backref cache cares about a specific root */
if (cache->is_reloc) {
root = find_reloc_root(cache->fs_info, cur->bytenr);
if (WARN_ON(!root))
return -ENOENT;
cur->root = root;
} else {
/*
* For generic purpose backref cache, reloc root node
* is useless.
*/
list_add(&cur->list, &cache->useless_node);
}
return 0;
}
edge = btrfs_backref_alloc_edge(cache);
if (!edge)
return -ENOMEM;
rb_node = rb_simple_search(&cache->rb_root, ref_key->offset);
if (!rb_node) {
/* Parent node not yet cached */
upper = btrfs_backref_alloc_node(cache, ref_key->offset,
cur->level + 1);
if (!upper) {
btrfs_backref_free_edge(cache, edge);
return -ENOMEM;
}
/*
* Backrefs for the upper level block isn't cached, add the
* block to pending list
*/
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
} else {
/* Parent node already cached */
upper = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
}
btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER);
return 0;
}
/*
* Handle indirect tree backref
*
* Indirect tree backref means, we only know which tree the node belongs to.
* We still need to do a tree search to find out the parents. This is for
* TREE_BLOCK_REF backref (keyed or inlined).
*
* @ref_key: The same as @ref_key in handle_direct_tree_backref()
* @tree_key: The first key of this tree block.
* @path: A clean (released) path, to avoid allocating path everytime
* the function get called.
*/
static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_key *ref_key,
struct btrfs_key *tree_key,
struct btrfs_backref_node *cur)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_backref_node *upper;
struct btrfs_backref_node *lower;
struct btrfs_backref_edge *edge;
struct extent_buffer *eb;
struct btrfs_root *root;
struct btrfs_key root_key;
struct rb_node *rb_node;
int level;
bool need_check = true;
int ret;
root_key.objectid = ref_key->offset;
root_key.type = BTRFS_ROOT_ITEM_KEY;
root_key.offset = (u64)-1;
root = btrfs_get_fs_root(fs_info, &root_key, false);
if (IS_ERR(root))
return PTR_ERR(root);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
cur->cowonly = 1;
if (btrfs_root_level(&root->root_item) == cur->level) {
/* Tree root */
ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr);
if (btrfs_should_ignore_reloc_root(root)) {
btrfs_put_root(root);
list_add(&cur->list, &cache->useless_node);
} else {
cur->root = root;
}
return 0;
}
level = cur->level + 1;
/* Search the tree to find parent blocks referring to the block */
path->search_commit_root = 1;
path->skip_locking = 1;
path->lowest_level = level;
ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0) {
btrfs_put_root(root);
return ret;
}
if (ret > 0 && path->slots[level] > 0)
path->slots[level]--;
eb = path->nodes[level];
if (btrfs_node_blockptr(eb, path->slots[level]) != cur->bytenr) {
btrfs_err(fs_info,
"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
cur->bytenr, level - 1, root->root_key.objectid,
tree_key->objectid, tree_key->type, tree_key->offset);
btrfs_put_root(root);
ret = -ENOENT;
goto out;
}
lower = cur;
/* Add all nodes and edges in the path */
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path->nodes[level]) {
ASSERT(btrfs_root_bytenr(&root->root_item) ==
lower->bytenr);
if (btrfs_should_ignore_reloc_root(root)) {
btrfs_put_root(root);
list_add(&lower->list, &cache->useless_node);
} else {
lower->root = root;
}
break;
}
edge = btrfs_backref_alloc_edge(cache);
if (!edge) {
btrfs_put_root(root);
ret = -ENOMEM;
goto out;
}
eb = path->nodes[level];
rb_node = rb_simple_search(&cache->rb_root, eb->start);
if (!rb_node) {
upper = btrfs_backref_alloc_node(cache, eb->start,
lower->level + 1);
if (!upper) {
btrfs_put_root(root);
btrfs_backref_free_edge(cache, edge);
ret = -ENOMEM;
goto out;
}
upper->owner = btrfs_header_owner(eb);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
upper->cowonly = 1;
/*
* If we know the block isn't shared we can avoid
* checking its backrefs.
*/
if (btrfs_block_can_be_shared(root, eb))
upper->checked = 0;
else
upper->checked = 1;
/*
* Add the block to pending list if we need to check its
* backrefs, we only do this once while walking up a
* tree as we will catch anything else later on.
*/
if (!upper->checked && need_check) {
need_check = false;
list_add_tail(&edge->list[UPPER],
&cache->pending_edge);
} else {
if (upper->checked)
need_check = true;
INIT_LIST_HEAD(&edge->list[UPPER]);
}
} else {
upper = rb_entry(rb_node, struct btrfs_backref_node,
rb_node);
ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
if (!upper->owner)
upper->owner = btrfs_header_owner(eb);
}
btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER);
if (rb_node) {
btrfs_put_root(root);
break;
}
lower = upper;
upper = NULL;
}
out:
btrfs_release_path(path);
return ret;
}
/*
* Add backref node @cur into @cache.
*
* NOTE: Even if the function returned 0, @cur is not yet cached as its upper
* links aren't yet bi-directional. Needs to finish such links.
*
* @path: Released path for indirect tree backref lookup
* @iter: Released backref iter for extent tree search
* @node_key: The first key of the tree block
*/
int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
struct btrfs_backref_node *cur)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *exist;
int ret;
ret = btrfs_backref_iter_start(iter, cur->bytenr);
if (ret < 0)
return ret;
/*
* We skip the first btrfs_tree_block_info, as we don't use the key
* stored in it, but fetch it from the tree block
*/
if (btrfs_backref_has_tree_block_info(iter)) {
ret = btrfs_backref_iter_next(iter);
if (ret < 0)
goto out;
/* No extra backref? This means the tree block is corrupted */
if (ret > 0) {
ret = -EUCLEAN;
goto out;
}
}
WARN_ON(cur->checked);
if (!list_empty(&cur->upper)) {
/*
* The backref was added previously when processing backref of
* type BTRFS_TREE_BLOCK_REF_KEY
*/
ASSERT(list_is_singular(&cur->upper));
edge = list_entry(cur->upper.next, struct btrfs_backref_edge,
list[LOWER]);
ASSERT(list_empty(&edge->list[UPPER]));
exist = edge->node[UPPER];
/*
* Add the upper level block to pending list if we need check
* its backrefs
*/
if (!exist->checked)
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
} else {
exist = NULL;
}
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) {
struct extent_buffer *eb;
struct btrfs_key key;
int type;
cond_resched();
eb = btrfs_backref_get_eb(iter);
key.objectid = iter->bytenr;
if (btrfs_backref_iter_is_inline_ref(iter)) {
struct btrfs_extent_inline_ref *iref;
/* Update key for inline backref */
iref = (struct btrfs_extent_inline_ref *)
((unsigned long)iter->cur_ptr);
type = btrfs_get_extent_inline_ref_type(eb, iref,
BTRFS_REF_TYPE_BLOCK);
if (type == BTRFS_REF_TYPE_INVALID) {
ret = -EUCLEAN;
goto out;
}
key.type = type;
key.offset = btrfs_extent_inline_ref_offset(eb, iref);
} else {
key.type = iter->cur_key.type;
key.offset = iter->cur_key.offset;
}
/*
* Parent node found and matches current inline ref, no need to
* rebuild this node for this inline ref
*/
if (exist &&
((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
exist->owner == key.offset) ||
(key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
exist->bytenr == key.offset))) {
exist = NULL;
continue;
}
/* SHARED_BLOCK_REF means key.offset is the parent bytenr */
if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
ret = handle_direct_tree_backref(cache, &key, cur);
if (ret < 0)
goto out;
continue;
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
ret = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_handle_fs_error(fs_info, ret, NULL);
goto out;
} else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
continue;
}
/*
* key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
* means the root objectid. We need to search the tree to get
* its parent bytenr.
*/
ret = handle_indirect_tree_backref(cache, path, &key, node_key,
cur);
if (ret < 0)
goto out;
}
ret = 0;
cur->checked = 1;
WARN_ON(exist);
out:
btrfs_backref_iter_release(iter);
return ret;
}

6
fs/btrfs/backref.h
View File

@ -363,4 +363,10 @@ static inline void btrfs_backref_panic(struct btrfs_fs_info *fs_info,
bytenr);
}
int btrfs_backref_add_tree_node(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
struct btrfs_backref_node *cur);
#endif

357
fs/btrfs/relocation.c
View File

@ -377,360 +377,6 @@ static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
return btrfs_get_fs_root(fs_info, &key, false);
}
/*
* Handle direct tree backref
*
* Direct tree backref means, the backref item shows its parent bytenr
* directly. This is for SHARED_BLOCK_REF backref (keyed or inlined).
*
* @ref_key: The converted backref key.
* For keyed backref, it's the item key.
* For inlined backref, objectid is the bytenr,
* type is btrfs_inline_ref_type, offset is
* btrfs_inline_ref_offset.
*/
static int handle_direct_tree_backref(struct btrfs_backref_cache *cache,
struct btrfs_key *ref_key,
struct btrfs_backref_node *cur)
{
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *upper;
struct rb_node *rb_node;
ASSERT(ref_key->type == BTRFS_SHARED_BLOCK_REF_KEY);
/* Only reloc root uses backref pointing to itself */
if (ref_key->objectid == ref_key->offset) {
struct btrfs_root *root;
cur->is_reloc_root = 1;
/* Only reloc backref cache cares about a specific root */
if (cache->is_reloc) {
root = find_reloc_root(cache->fs_info, cur->bytenr);
if (WARN_ON(!root))
return -ENOENT;
cur->root = root;
} else {
/*
* For generic purpose backref cache, reloc root node
* is useless.
*/
list_add(&cur->list, &cache->useless_node);
}
return 0;
}
edge = btrfs_backref_alloc_edge(cache);
if (!edge)
return -ENOMEM;
rb_node = rb_simple_search(&cache->rb_root, ref_key->offset);
if (!rb_node) {
/* Parent node not yet cached */
upper = btrfs_backref_alloc_node(cache, ref_key->offset,
cur->level + 1);
if (!upper) {
btrfs_backref_free_edge(cache, edge);
return -ENOMEM;
}
/*
* Backrefs for the upper level block isn't cached, add the
* block to pending list
*/
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
} else {
/* Parent node already cached */
upper = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
}
btrfs_backref_link_edge(edge, cur, upper, LINK_LOWER);
return 0;
}
/*
* Handle indirect tree backref
*
* Indirect tree backref means, we only know which tree the node belongs to.
* We still need to do a tree search to find out the parents. This is for
* TREE_BLOCK_REF backref (keyed or inlined).
*
* @ref_key: The same as @ref_key in handle_direct_tree_backref()
* @tree_key: The first key of this tree block.
* @path: A clean (released) path, to avoid allocating path everytime
* the function get called.
*/
static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_key *ref_key,
struct btrfs_key *tree_key,
struct btrfs_backref_node *cur)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_backref_node *upper;
struct btrfs_backref_node *lower;
struct btrfs_backref_edge *edge;
struct extent_buffer *eb;
struct btrfs_root *root;
struct btrfs_key root_key;
struct rb_node *rb_node;
int level;
bool need_check = true;
int ret;
root_key.objectid = ref_key->offset;
root_key.type = BTRFS_ROOT_ITEM_KEY;
root_key.offset = (u64)-1;
root = btrfs_get_fs_root(fs_info, &root_key, false);
if (IS_ERR(root))
return PTR_ERR(root);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
cur->cowonly = 1;
if (btrfs_root_level(&root->root_item) == cur->level) {
/* Tree root */
ASSERT(btrfs_root_bytenr(&root->root_item) == cur->bytenr);
if (btrfs_should_ignore_reloc_root(root)) {
btrfs_put_root(root);
list_add(&cur->list, &cache->useless_node);
} else {
cur->root = root;
}
return 0;
}
level = cur->level + 1;
/* Search the tree to find parent blocks referring to the block */
path->search_commit_root = 1;
path->skip_locking = 1;
path->lowest_level = level;
ret = btrfs_search_slot(NULL, root, tree_key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0) {
btrfs_put_root(root);
return ret;
}
if (ret > 0 && path->slots[level] > 0)
path->slots[level]--;
eb = path->nodes[level];
if (btrfs_node_blockptr(eb, path->slots[level]) != cur->bytenr) {
btrfs_err(fs_info,
"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
cur->bytenr, level - 1, root->root_key.objectid,
tree_key->objectid, tree_key->type, tree_key->offset);
btrfs_put_root(root);
ret = -ENOENT;
goto out;
}
lower = cur;
/* Add all nodes and edges in the path */
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path->nodes[level]) {
ASSERT(btrfs_root_bytenr(&root->root_item) ==
lower->bytenr);
if (btrfs_should_ignore_reloc_root(root)) {
btrfs_put_root(root);
list_add(&lower->list, &cache->useless_node);
} else {
lower->root = root;
}
break;
}
edge = btrfs_backref_alloc_edge(cache);
if (!edge) {
btrfs_put_root(root);
ret = -ENOMEM;
goto out;
}
eb = path->nodes[level];
rb_node = rb_simple_search(&cache->rb_root, eb->start);
if (!rb_node) {
upper = btrfs_backref_alloc_node(cache, eb->start,
lower->level + 1);
if (!upper) {
btrfs_put_root(root);
btrfs_backref_free_edge(cache, edge);
ret = -ENOMEM;
goto out;
}
upper->owner = btrfs_header_owner(eb);
if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
upper->cowonly = 1;
/*
* If we know the block isn't shared we can avoid
* checking its backrefs.
*/
if (btrfs_block_can_be_shared(root, eb))
upper->checked = 0;
else
upper->checked = 1;
/*
* Add the block to pending list if we need to check its
* backrefs, we only do this once while walking up a
* tree as we will catch anything else later on.
*/
if (!upper->checked && need_check) {
need_check = false;
list_add_tail(&edge->list[UPPER],
&cache->pending_edge);
} else {
if (upper->checked)
need_check = true;
INIT_LIST_HEAD(&edge->list[UPPER]);
}
} else {
upper = rb_entry(rb_node, struct btrfs_backref_node,
rb_node);
ASSERT(upper->checked);
INIT_LIST_HEAD(&edge->list[UPPER]);
if (!upper->owner)
upper->owner = btrfs_header_owner(eb);
}
btrfs_backref_link_edge(edge, lower, upper, LINK_LOWER);
if (rb_node) {
btrfs_put_root(root);
break;
}
lower = upper;
upper = NULL;
}
out:
btrfs_release_path(path);
return ret;
}
static int handle_one_tree_block(struct btrfs_backref_cache *cache,
struct btrfs_path *path,
struct btrfs_backref_iter *iter,
struct btrfs_key *node_key,
struct btrfs_backref_node *cur)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *exist;
int ret;
ret = btrfs_backref_iter_start(iter, cur->bytenr);
if (ret < 0)
return ret;
/*
* We skip the first btrfs_tree_block_info, as we don't use the key
* stored in it, but fetch it from the tree block
*/
if (btrfs_backref_has_tree_block_info(iter)) {
ret = btrfs_backref_iter_next(iter);
if (ret < 0)
goto out;
/* No extra backref? This means the tree block is corrupted */
if (ret > 0) {
ret = -EUCLEAN;
goto out;
}
}
WARN_ON(cur->checked);
if (!list_empty(&cur->upper)) {
/*
* the backref was added previously when processing
* backref of type BTRFS_TREE_BLOCK_REF_KEY
*/
ASSERT(list_is_singular(&cur->upper));
edge = list_entry(cur->upper.next, struct btrfs_backref_edge,
list[LOWER]);
ASSERT(list_empty(&edge->list[UPPER]));
exist = edge->node[UPPER];
/*
* add the upper level block to pending list if we need
* check its backrefs
*/
if (!exist->checked)
list_add_tail(&edge->list[UPPER], &cache->pending_edge);
} else {
exist = NULL;
}
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) {
struct extent_buffer *eb;
struct btrfs_key key;
int type;
cond_resched();
eb = btrfs_backref_get_eb(iter);
key.objectid = iter->bytenr;
if (btrfs_backref_iter_is_inline_ref(iter)) {
struct btrfs_extent_inline_ref *iref;
/* update key for inline back ref */
iref = (struct btrfs_extent_inline_ref *)
((unsigned long)iter->cur_ptr);
type = btrfs_get_extent_inline_ref_type(eb, iref,
BTRFS_REF_TYPE_BLOCK);
if (type == BTRFS_REF_TYPE_INVALID) {
ret = -EUCLEAN;
goto out;
}
key.type = type;
key.offset = btrfs_extent_inline_ref_offset(eb, iref);
} else {
key.type = iter->cur_key.type;
key.offset = iter->cur_key.offset;
}
/*
* Parent node found and matches current inline ref, no need to
* rebuild this node for this inline ref.
*/
if (exist &&
((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
exist->owner == key.offset) ||
(key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
exist->bytenr == key.offset))) {
exist = NULL;
continue;
}
/* SHARED_BLOCK_REF means key.offset is the parent bytenr */
if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
ret = handle_direct_tree_backref(cache, &key, cur);
if (ret < 0)
goto out;
continue;
} else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
ret = -EINVAL;
btrfs_print_v0_err(fs_info);
btrfs_handle_fs_error(fs_info, ret, NULL);
goto out;
} else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
continue;
}
/*
* key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
* means the root objectid. We need to search the tree to get
* its parent bytenr.
*/
ret = handle_indirect_tree_backref(cache, path, &key, node_key,
cur);
if (ret < 0)
goto out;
}
ret = 0;
cur->checked = 1;
WARN_ON(exist);
out:
btrfs_backref_iter_release(iter);
return ret;
}
/*
* In handle_one_tree_backref(), we have only linked the lower node to the edge,
* but the upper node hasn't been linked to the edge.
@ -969,7 +615,8 @@ static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
/* Breadth-first search to build backref cache */
do {
ret = handle_one_tree_block(cache, path, iter, node_key, cur);
ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
cur);
if (ret < 0) {
err = ret;
goto out;