blob: 4ba1ab9cc76db89935ed619d8886715d0eeaa6ad [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2009 Oracle. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/rbtree.h>
#include <linux/slab.h>
#include <linux/error-injection.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "volumes.h"
#include "locking.h"
#include "btrfs_inode.h"
#include "async-thread.h"
#include "free-space-cache.h"
#include "inode-map.h"
#include "qgroup.h"
#include "print-tree.h"
#include "delalloc-space.h"
#include "block-group.h"
#include "backref.h"
#include "misc.h"
/*
* Relocation overview
*
* [What does relocation do]
*
* The objective of relocation is to relocate all extents of the target block
* group to other block groups.
* This is utilized by resize (shrink only), profile converting, compacting
* space, or balance routine to spread chunks over devices.
*
* Before | After
* ------------------------------------------------------------------
* BG A: 10 data extents | BG A: deleted
* BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
* BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
*
* [How does relocation work]
*
* 1. Mark the target block group read-only
* New extents won't be allocated from the target block group.
*
* 2.1 Record each extent in the target block group
* To build a proper map of extents to be relocated.
*
* 2.2 Build data reloc tree and reloc trees
* Data reloc tree will contain an inode, recording all newly relocated
* data extents.
* There will be only one data reloc tree for one data block group.
*
* Reloc tree will be a special snapshot of its source tree, containing
* relocated tree blocks.
* Each tree referring to a tree block in target block group will get its
* reloc tree built.
*
* 2.3 Swap source tree with its corresponding reloc tree
* Each involved tree only refers to new extents after swap.
*
* 3. Cleanup reloc trees and data reloc tree.
* As old extents in the target block group are still referenced by reloc
* trees, we need to clean them up before really freeing the target block
* group.
*
* The main complexity is in steps 2.2 and 2.3.
*
* The entry point of relocation is relocate_block_group() function.
*/
#define RELOCATION_RESERVED_NODES 256
/*
* map address of tree root to tree
*/
struct mapping_node {
struct {
struct rb_node rb_node;
u64 bytenr;
}; /* Use rb_simle_node for search/insert */
void *data;
};
struct mapping_tree {
struct rb_root rb_root;
spinlock_t lock;
};
/*
* present a tree block to process
*/
struct tree_block {
struct {
struct rb_node rb_node;
u64 bytenr;
}; /* Use rb_simple_node for search/insert */
struct btrfs_key key;
unsigned int level:8;
unsigned int key_ready:1;
};
#define MAX_EXTENTS 128
struct file_extent_cluster {
u64 start;
u64 end;
u64 boundary[MAX_EXTENTS];
unsigned int nr;
};
struct reloc_control {
/* block group to relocate */
struct btrfs_block_group *block_group;
/* extent tree */
struct btrfs_root *extent_root;
/* inode for moving data */
struct inode *data_inode;
struct btrfs_block_rsv *block_rsv;
struct btrfs_backref_cache backref_cache;
struct file_extent_cluster cluster;
/* tree blocks have been processed */
struct extent_io_tree processed_blocks;
/* map start of tree root to corresponding reloc tree */
struct mapping_tree reloc_root_tree;
/* list of reloc trees */
struct list_head reloc_roots;
/* list of subvolume trees that get relocated */
struct list_head dirty_subvol_roots;
/* size of metadata reservation for merging reloc trees */
u64 merging_rsv_size;
/* size of relocated tree nodes */
u64 nodes_relocated;
/* reserved size for block group relocation*/
u64 reserved_bytes;
u64 search_start;
u64 extents_found;
unsigned int stage:8;
unsigned int create_reloc_tree:1;
unsigned int merge_reloc_tree:1;
unsigned int found_file_extent:1;
};
/* stages of data relocation */
#define MOVE_DATA_EXTENTS 0
#define UPDATE_DATA_PTRS 1
static void mark_block_processed(struct reloc_control *rc,
struct btrfs_backref_node *node)
{
u32 blocksize;
if (node->level == 0 ||
in_range(node->bytenr, rc->block_group->start,
rc->block_group->length)) {
blocksize = rc->extent_root->fs_info->nodesize;
set_extent_bits(&rc->processed_blocks, node->bytenr,
node->bytenr + blocksize - 1, EXTENT_DIRTY);
}
node->processed = 1;
}
static void mapping_tree_init(struct mapping_tree *tree)
{
tree->rb_root = RB_ROOT;
spin_lock_init(&tree->lock);
}
/*
* walk up backref nodes until reach node presents tree root
*/
static struct btrfs_backref_node *walk_up_backref(
struct btrfs_backref_node *node,
struct btrfs_backref_edge *edges[], int *index)
{
struct btrfs_backref_edge *edge;
int idx = *index;
while (!list_empty(&node->upper)) {
edge = list_entry(node->upper.next,
struct btrfs_backref_edge, list[LOWER]);
edges[idx++] = edge;
node = edge->node[UPPER];
}
BUG_ON(node->detached);
*index = idx;
return node;
}
/*
* walk down backref nodes to find start of next reference path
*/
static struct btrfs_backref_node *walk_down_backref(
struct btrfs_backref_edge *edges[], int *index)
{
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *lower;
int idx = *index;
while (idx > 0) {
edge = edges[idx - 1];
lower = edge->node[LOWER];
if (list_is_last(&edge->list[LOWER], &lower->upper)) {
idx--;
continue;
}
edge = list_entry(edge->list[LOWER].next,
struct btrfs_backref_edge, list[LOWER]);
edges[idx - 1] = edge;
*index = idx;
return edge->node[UPPER];
}
*index = 0;
return NULL;
}
static void update_backref_node(struct btrfs_backref_cache *cache,
struct btrfs_backref_node *node, u64 bytenr)
{
struct rb_node *rb_node;
rb_erase(&node->rb_node, &cache->rb_root);
node->bytenr = bytenr;
rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
if (rb_node)
btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
}
/*
* update backref cache after a transaction commit
*/
static int update_backref_cache(struct btrfs_trans_handle *trans,
struct btrfs_backref_cache *cache)
{
struct btrfs_backref_node *node;
int level = 0;
if (cache->last_trans == 0) {
cache->last_trans = trans->transid;
return 0;
}
if (cache->last_trans == trans->transid)
return 0;
/*
* detached nodes are used to avoid unnecessary backref
* lookup. transaction commit changes the extent tree.
* so the detached nodes are no longer useful.
*/
while (!list_empty(&cache->detached)) {
node = list_entry(cache->detached.next,
struct btrfs_backref_node, list);
btrfs_backref_cleanup_node(cache, node);
}
while (!list_empty(&cache->changed)) {
node = list_entry(cache->changed.next,
struct btrfs_backref_node, list);
list_del_init(&node->list);
BUG_ON(node->pending);
update_backref_node(cache, node, node->new_bytenr);
}
/*
* some nodes can be left in the pending list if there were
* errors during processing the pending nodes.
*/
for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
list_for_each_entry(node, &cache->pending[level], list) {
BUG_ON(!node->pending);
if (node->bytenr == node->new_bytenr)
continue;
update_backref_node(cache, node, node->new_bytenr);
}
}
cache->last_trans = 0;
return 1;
}
static bool reloc_root_is_dead(struct btrfs_root *root)
{
/*
* Pair with set_bit/clear_bit in clean_dirty_subvols and
* btrfs_update_reloc_root. We need to see the updated bit before
* trying to access reloc_root
*/
smp_rmb();
if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
return true;
return false;
}
/*
* Check if this subvolume tree has valid reloc tree.
*
* Reloc tree after swap is considered dead, thus not considered as valid.
* This is enough for most callers, as they don't distinguish dead reloc root
* from no reloc root. But btrfs_should_ignore_reloc_root() below is a
* special case.
*/
static bool have_reloc_root(struct btrfs_root *root)
{
if (reloc_root_is_dead(root))
return false;
if (!root->reloc_root)
return false;
return true;
}
int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
{
struct btrfs_root *reloc_root;
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return 0;
/* This root has been merged with its reloc tree, we can ignore it */
if (reloc_root_is_dead(root))
return 1;
reloc_root = root->reloc_root;
if (!reloc_root)
return 0;
if (btrfs_header_generation(reloc_root->commit_root) ==
root->fs_info->running_transaction->transid)
return 0;
/*
* if there is reloc tree and it was created in previous
* transaction backref lookup can find the reloc tree,
* so backref node for the fs tree root is useless for
* relocation.
*/
return 1;
}
/*
* find reloc tree by address of tree root
*/
struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
{
struct reloc_control *rc = fs_info->reloc_ctl;
struct rb_node *rb_node;
struct mapping_node *node;
struct btrfs_root *root = NULL;
ASSERT(rc);
spin_lock(&rc->reloc_root_tree.lock);
rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
root = (struct btrfs_root *)node->data;
}
spin_unlock(&rc->reloc_root_tree.lock);
return btrfs_grab_root(root);
}
/*
* For useless nodes, do two major clean ups:
*
* - Cleanup the children edges and nodes
* If child node is also orphan (no parent) during cleanup, then the child
* node will also be cleaned up.
*
* - Freeing up leaves (level 0), keeps nodes detached
* For nodes, the node is still cached as "detached"
*
* Return false if @node is not in the @useless_nodes list.
* Return true if @node is in the @useless_nodes list.
*/
static bool handle_useless_nodes(struct reloc_control *rc,
struct btrfs_backref_node *node)
{
struct btrfs_backref_cache *cache = &rc->backref_cache;
struct list_head *useless_node = &cache->useless_node;
bool ret = false;
while (!list_empty(useless_node)) {
struct btrfs_backref_node *cur;
cur = list_first_entry(useless_node, struct btrfs_backref_node,
list);
list_del_init(&cur->list);
/* Only tree root nodes can be added to @useless_nodes */
ASSERT(list_empty(&cur->upper));
if (cur == node)
ret = true;
/* The node is the lowest node */
if (cur->lowest) {
list_del_init(&cur->lower);
cur->lowest = 0;
}
/* Cleanup the lower edges */
while (!list_empty(&cur->lower)) {
struct btrfs_backref_edge *edge;
struct btrfs_backref_node *lower;
edge = list_entry(cur->lower.next,
struct btrfs_backref_edge, list[UPPER]);
list_del(&edge->list[UPPER]);
list_del(&edge->list[LOWER]);
lower = edge->node[LOWER];
btrfs_backref_free_edge(cache, edge);
/* Child node is also orphan, queue for cleanup */
if (list_empty(&lower->upper))
list_add(&lower->list, useless_node);
}
/* Mark this block processed for relocation */
mark_block_processed(rc, cur);
/*
* Backref nodes for tree leaves are deleted from the cache.
* Backref nodes for upper level tree blocks are left in the
* cache to avoid unnecessary backref lookup.
*/
if (cur->level > 0) {
list_add(&cur->list, &cache->detached);
cur->detached = 1;
} else {
rb_erase(&cur->rb_node, &cache->rb_root);
btrfs_backref_free_node(cache, cur);
}
}
return ret;
}
/*
* Build backref tree for a given tree block. Root of the backref tree
* corresponds the tree block, leaves of the backref tree correspond roots of
* b-trees that reference the tree block.
*
* The basic idea of this function is check backrefs of a given block to find
* upper level blocks that reference the block, and then check backrefs of
* these upper level blocks recursively. The recursion stops when tree root is
* reached or backrefs for the block is cached.
*
* NOTE: if we find that backrefs for a block are cached, we know backrefs for
* all upper level blocks that directly/indirectly reference the block are also
* cached.
*/
static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
struct reloc_control *rc, struct btrfs_key *node_key,
int level, u64 bytenr)
{
struct btrfs_backref_iter *iter;
struct btrfs_backref_cache *cache = &rc->backref_cache;
/* For searching parent of TREE_BLOCK_REF */
struct btrfs_path *path;
struct btrfs_backref_node *cur;
struct btrfs_backref_node *node = NULL;
struct btrfs_backref_edge *edge;
int ret;
int err = 0;
iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info, GFP_NOFS);
if (!iter)
return ERR_PTR(-ENOMEM);
path = btrfs_alloc_path();
if (!path) {
err = -ENOMEM;
goto out;
}
node = btrfs_backref_alloc_node(cache, bytenr, level);
if (!node) {
err = -ENOMEM;
goto out;
}
node->lowest = 1;
cur = node;
/* Breadth-first search to build backref cache */
do {
ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
cur);
if (ret < 0) {
err = ret;
goto out;
}
edge = list_first_entry_or_null(&cache->pending_edge,
struct btrfs_backref_edge, list[UPPER]);
/*
* The pending list isn't empty, take the first block to
* process
*/
if (edge) {
list_del_init(&edge->list[UPPER]);
cur = edge->node[UPPER];
}
} while (edge);
/* Finish the upper linkage of newly added edges/nodes */
ret = btrfs_backref_finish_upper_links(cache, node);
if (ret < 0) {
err = ret;
goto out;
}
if (handle_useless_nodes(rc, node))
node = NULL;
out:
btrfs_backref_iter_free(iter);
btrfs_free_path(path);
if (err) {
btrfs_backref_error_cleanup(cache, node);
return ERR_PTR(err);
}
ASSERT(!node || !node->detached);
ASSERT(list_empty(&cache->useless_node) &&
list_empty(&cache->pending_edge));
return node;
}
/*
* helper to add backref node for the newly created snapshot.
* the backref node is created by cloning backref node that
* corresponds to root of source tree
*/
static int clone_backref_node(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_root *src,
struct btrfs_root *dest)
{
struct btrfs_root *reloc_root = src->reloc_root;
struct btrfs_backref_cache *cache = &rc->backref_cache;
struct btrfs_backref_node *node = NULL;
struct btrfs_backref_node *new_node;
struct btrfs_backref_edge *edge;
struct btrfs_backref_edge *new_edge;
struct rb_node *rb_node;
if (cache->last_trans > 0)
update_backref_cache(trans, cache);
rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
if (rb_node) {
node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
if (node->detached)
node = NULL;
else
BUG_ON(node->new_bytenr != reloc_root->node->start);
}
if (!node) {
rb_node = rb_simple_search(&cache->rb_root,
reloc_root->commit_root->start);
if (rb_node) {
node = rb_entry(rb_node, struct btrfs_backref_node,
rb_node);
BUG_ON(node->detached);
}
}
if (!node)
return 0;
new_node = btrfs_backref_alloc_node(cache, dest->node->start,
node->level);
if (!new_node)
return -ENOMEM;
new_node->lowest = node->lowest;
new_node->checked = 1;
new_node->root = btrfs_grab_root(dest);
ASSERT(new_node->root);
if (!node->lowest) {
list_for_each_entry(edge, &node->lower, list[UPPER]) {
new_edge = btrfs_backref_alloc_edge(cache);
if (!new_edge)
goto fail;
btrfs_backref_link_edge(new_edge, edge->node[LOWER],
new_node, LINK_UPPER);
}
} else {
list_add_tail(&new_node->lower, &cache->leaves);
}
rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
&new_node->rb_node);
if (rb_node)
btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
if (!new_node->lowest) {
list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
list_add_tail(&new_edge->list[LOWER],
&new_edge->node[LOWER]->upper);
}
}
return 0;
fail:
while (!list_empty(&new_node->lower)) {
new_edge = list_entry(new_node->lower.next,
struct btrfs_backref_edge, list[UPPER]);
list_del(&new_edge->list[UPPER]);
btrfs_backref_free_edge(cache, new_edge);
}
btrfs_backref_free_node(cache, new_node);
return -ENOMEM;
}
/*
* helper to add 'address of tree root -> reloc tree' mapping
*/
static int __must_check __add_reloc_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct rb_node *rb_node;
struct mapping_node *node;
struct reloc_control *rc = fs_info->reloc_ctl;
node = kmalloc(sizeof(*node), GFP_NOFS);
if (!node)
return -ENOMEM;
node->bytenr = root->commit_root->start;
node->data = root;
spin_lock(&rc->reloc_root_tree.lock);
rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
node->bytenr, &node->rb_node);
spin_unlock(&rc->reloc_root_tree.lock);
if (rb_node) {
btrfs_panic(fs_info, -EEXIST,
"Duplicate root found for start=%llu while inserting into relocation tree",
node->bytenr);
}
list_add_tail(&root->root_list, &rc->reloc_roots);
return 0;
}
/*
* helper to delete the 'address of tree root -> reloc tree'
* mapping
*/
static void __del_reloc_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct rb_node *rb_node;
struct mapping_node *node = NULL;
struct reloc_control *rc = fs_info->reloc_ctl;
bool put_ref = false;
if (rc && root->node) {
spin_lock(&rc->reloc_root_tree.lock);
rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
root->commit_root->start);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
RB_CLEAR_NODE(&node->rb_node);
}
spin_unlock(&rc->reloc_root_tree.lock);
if (!node)
return;
BUG_ON((struct btrfs_root *)node->data != root);
}
/*
* We only put the reloc root here if it's on the list. There's a lot
* of places where the pattern is to splice the rc->reloc_roots, process
* the reloc roots, and then add the reloc root back onto
* rc->reloc_roots. If we call __del_reloc_root while it's off of the
* list we don't want the reference being dropped, because the guy
* messing with the list is in charge of the reference.
*/
spin_lock(&fs_info->trans_lock);
if (!list_empty(&root->root_list)) {
put_ref = true;
list_del_init(&root->root_list);
}
spin_unlock(&fs_info->trans_lock);
if (put_ref)
btrfs_put_root(root);
kfree(node);
}
/*
* helper to update the 'address of tree root -> reloc tree'
* mapping
*/
static int __update_reloc_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct rb_node *rb_node;
struct mapping_node *node = NULL;
struct reloc_control *rc = fs_info->reloc_ctl;
spin_lock(&rc->reloc_root_tree.lock);
rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
root->commit_root->start);
if (rb_node) {
node = rb_entry(rb_node, struct mapping_node, rb_node);
rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
}
spin_unlock(&rc->reloc_root_tree.lock);
if (!node)
return 0;
BUG_ON((struct btrfs_root *)node->data != root);
spin_lock(&rc->reloc_root_tree.lock);
node->bytenr = root->node->start;
rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
node->bytenr, &node->rb_node);
spin_unlock(&rc->reloc_root_tree.lock);
if (rb_node)
btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
return 0;
}
static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 objectid)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *reloc_root;
struct extent_buffer *eb;
struct btrfs_root_item *root_item;
struct btrfs_key root_key;
int ret;
root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
BUG_ON(!root_item);
root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
root_key.type = BTRFS_ROOT_ITEM_KEY;
root_key.offset = objectid;
if (root->root_key.objectid == objectid) {
u64 commit_root_gen;
/* called by btrfs_init_reloc_root */
ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
BTRFS_TREE_RELOC_OBJECTID);
BUG_ON(ret);
/*
* Set the last_snapshot field to the generation of the commit
* root - like this ctree.c:btrfs_block_can_be_shared() behaves
* correctly (returns true) when the relocation root is created
* either inside the critical section of a transaction commit
* (through transaction.c:qgroup_account_snapshot()) and when
* it's created before the transaction commit is started.
*/
commit_root_gen = btrfs_header_generation(root->commit_root);
btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
} else {
/*
* called by btrfs_reloc_post_snapshot_hook.
* the source tree is a reloc tree, all tree blocks
* modified after it was created have RELOC flag
* set in their headers. so it's OK to not update
* the 'last_snapshot'.
*/
ret = btrfs_copy_root(trans, root, root->node, &eb,
BTRFS_TREE_RELOC_OBJECTID);
BUG_ON(ret);
}
memcpy(root_item, &root->root_item, sizeof(*root_item));
btrfs_set_root_bytenr(root_item, eb->start);
btrfs_set_root_level(root_item, btrfs_header_level(eb));
btrfs_set_root_generation(root_item, trans->transid);
if (root->root_key.objectid == objectid) {
btrfs_set_root_refs(root_item, 0);
memset(&root_item->drop_progress, 0,
sizeof(struct btrfs_disk_key));
root_item->drop_level = 0;
}
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
ret = btrfs_insert_root(trans, fs_info->tree_root,
&root_key, root_item);
BUG_ON(ret);
kfree(root_item);
reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
BUG_ON(IS_ERR(reloc_root));
set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
reloc_root->last_trans = trans->transid;
return reloc_root;
}
/*
* create reloc tree for a given fs tree. reloc tree is just a
* snapshot of the fs tree with special root objectid.
*
* The reloc_root comes out of here with two references, one for
* root->reloc_root, and another for being on the rc->reloc_roots list.
*/
int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *reloc_root;
struct reloc_control *rc = fs_info->reloc_ctl;
struct btrfs_block_rsv *rsv;
int clear_rsv = 0;
int ret;
if (!rc)
return 0;
/*
* The subvolume has reloc tree but the swap is finished, no need to
* create/update the dead reloc tree
*/
if (reloc_root_is_dead(root))
return 0;
/*
* This is subtle but important. We do not do
* record_root_in_transaction for reloc roots, instead we record their
* corresponding fs root, and then here we update the last trans for the
* reloc root. This means that we have to do this for the entire life
* of the reloc root, regardless of which stage of the relocation we are
* in.
*/
if (root->reloc_root) {
reloc_root = root->reloc_root;
reloc_root->last_trans = trans->transid;
return 0;
}
/*
* We are merging reloc roots, we do not need new reloc trees. Also
* reloc trees never need their own reloc tree.
*/
if (!rc->create_reloc_tree ||
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
return 0;
if (!trans->reloc_reserved) {
rsv = trans->block_rsv;
trans->block_rsv = rc->block_rsv;
clear_rsv = 1;
}
reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
if (clear_rsv)
trans->block_rsv = rsv;
ret = __add_reloc_root(reloc_root);
BUG_ON(ret < 0);
root->reloc_root = btrfs_grab_root(reloc_root);
return 0;
}
/*
* update root item of reloc tree
*/
int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *reloc_root;
struct btrfs_root_item *root_item;
int ret;
if (!have_reloc_root(root))
goto out;
reloc_root = root->reloc_root;
root_item = &reloc_root->root_item;
/*
* We are probably ok here, but __del_reloc_root() will drop its ref of
* the root. We have the ref for root->reloc_root, but just in case
* hold it while we update the reloc root.
*/
btrfs_grab_root(reloc_root);
/* root->reloc_root will stay until current relocation finished */
if (fs_info->reloc_ctl->merge_reloc_tree &&
btrfs_root_refs(root_item) == 0) {
set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
/*
* Mark the tree as dead before we change reloc_root so
* have_reloc_root will not touch it from now on.
*/
smp_wmb();
__del_reloc_root(reloc_root);
}
if (reloc_root->commit_root != reloc_root->node) {
__update_reloc_root(reloc_root);
btrfs_set_root_node(root_item, reloc_root->node);
free_extent_buffer(reloc_root->commit_root);
reloc_root->commit_root = btrfs_root_node(reloc_root);
}
ret = btrfs_update_root(trans, fs_info->tree_root,
&reloc_root->root_key, root_item);
BUG_ON(ret);
btrfs_put_root(reloc_root);
out:
return 0;
}
/*
* helper to find first cached inode with inode number >= objectid
* in a subvolume
*/
static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
{
struct rb_node *node;
struct rb_node *prev;
struct btrfs_inode *entry;
struct inode *inode;
spin_lock(&root->inode_lock);
again:
node = root->inode_tree.rb_node;
prev = NULL;
while (node) {
prev = node;
entry = rb_entry(node, struct btrfs_inode, rb_node);
if (objectid < btrfs_ino(entry))
node = node->rb_left;
else if (objectid > btrfs_ino(entry))
node = node->rb_right;
else
break;
}
if (!node) {
while (prev) {
entry = rb_entry(prev, struct btrfs_inode, rb_node);
if (objectid <= btrfs_ino(entry)) {
node = prev;
break;
}
prev = rb_next(prev);
}
}
while (node) {
entry = rb_entry(node, struct btrfs_inode, rb_node);
inode = igrab(&entry->vfs_inode);
if (inode) {
spin_unlock(&root->inode_lock);
return inode;
}
objectid = btrfs_ino(entry) + 1;
if (cond_resched_lock(&root->inode_lock))
goto again;
node = rb_next(node);
}
spin_unlock(&root->inode_lock);
return NULL;
}
/*
* get new location of data
*/
static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
u64 bytenr, u64 num_bytes)
{
struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
struct btrfs_path *path;
struct btrfs_file_extent_item *fi;
struct extent_buffer *leaf;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
bytenr -= BTRFS_I(reloc_inode)->index_cnt;
ret = btrfs_lookup_file_extent(NULL, root, path,
btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
if (ret < 0)
goto out;
if (ret > 0) {
ret = -ENOENT;
goto out;
}
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
btrfs_file_extent_compression(leaf, fi) ||
btrfs_file_extent_encryption(leaf, fi) ||
btrfs_file_extent_other_encoding(leaf, fi));
if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
ret = -EINVAL;
goto out;
}
*new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
ret = 0;
out:
btrfs_free_path(path);
return ret;
}
/*
* update file extent items in the tree leaf to point to
* the new locations.
*/
static noinline_for_stack
int replace_file_extents(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_root *root,
struct extent_buffer *leaf)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
struct inode *inode = NULL;
u64 parent;
u64 bytenr;
u64 new_bytenr = 0;
u64 num_bytes;
u64 end;
u32 nritems;
u32 i;
int ret = 0;
int first = 1;
int dirty = 0;
if (rc->stage != UPDATE_DATA_PTRS)
return 0;
/* reloc trees always use full backref */
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
parent = leaf->start;
else
parent = 0;
nritems = btrfs_header_nritems(leaf);
for (i = 0; i < nritems; i++) {
struct btrfs_ref ref = { 0 };
cond_resched();
btrfs_item_key_to_cpu(leaf, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
if (bytenr == 0)
continue;
if (!in_range(bytenr, rc->block_group->start,
rc->block_group->length))
continue;
/*
* if we are modifying block in fs tree, wait for readpage
* to complete and drop the extent cache
*/
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
if (first) {
inode = find_next_inode(root, key.objectid);
first = 0;
} else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
btrfs_add_delayed_iput(inode);
inode = find_next_inode(root, key.objectid);
}
if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
end = key.offset +
btrfs_file_extent_num_bytes(leaf, fi);
WARN_ON(!IS_ALIGNED(key.offset,
fs_info->sectorsize));
WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
end--;
ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
key.offset, end);
if (!ret)
continue;
btrfs_drop_extent_cache(BTRFS_I(inode),
key.offset, end, 1);
unlock_extent(&BTRFS_I(inode)->io_tree,
key.offset, end);
}
}
ret = get_new_location(rc->data_inode, &new_bytenr,
bytenr, num_bytes);
if (ret) {
/*
* Don't have to abort since we've not changed anything
* in the file extent yet.
*/
break;
}
btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
dirty = 1;
key.offset -= btrfs_file_extent_offset(leaf, fi);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
num_bytes, parent);
ref.real_root = root->root_key.objectid;
btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
key.objectid, key.offset);
ret = btrfs_inc_extent_ref(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
num_bytes, parent);
ref.real_root = root->root_key.objectid;
btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
key.objectid, key.offset);
ret = btrfs_free_extent(trans, &ref);
if (ret) {
btrfs_abort_transaction(trans, ret);
break;
}
}
if (dirty)
btrfs_mark_buffer_dirty(leaf);
if (inode)
btrfs_add_delayed_iput(inode);
return ret;
}
static noinline_for_stack
int memcmp_node_keys(struct extent_buffer *eb, int slot,
struct btrfs_path *path, int level)
{
struct btrfs_disk_key key1;
struct btrfs_disk_key key2;
btrfs_node_key(eb, &key1, slot);
btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
return memcmp(&key1, &key2, sizeof(key1));
}
/*
* try to replace tree blocks in fs tree with the new blocks
* in reloc tree. tree blocks haven't been modified since the
* reloc tree was create can be replaced.
*
* if a block was replaced, level of the block + 1 is returned.
* if no block got replaced, 0 is returned. if there are other
* errors, a negative error number is returned.
*/
static noinline_for_stack
int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
struct btrfs_root *dest, struct btrfs_root *src,
struct btrfs_path *path, struct btrfs_key *next_key,
int lowest_level, int max_level)
{
struct btrfs_fs_info *fs_info = dest->fs_info;
struct extent_buffer *eb;
struct extent_buffer *parent;
struct btrfs_ref ref = { 0 };
struct btrfs_key key;
u64 old_bytenr;
u64 new_bytenr;
u64 old_ptr_gen;
u64 new_ptr_gen;
u64 last_snapshot;
u32 blocksize;
int cow = 0;
int level;
int ret;
int slot;
BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
last_snapshot = btrfs_root_last_snapshot(&src->root_item);
again:
slot = path->slots[lowest_level];
btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
eb = btrfs_lock_root_node(dest);
btrfs_set_lock_blocking_write(eb);
level = btrfs_header_level(eb);
if (level < lowest_level) {
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
return 0;
}
if (cow) {
ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
BUG_ON(ret);
}
btrfs_set_lock_blocking_write(eb);
if (next_key) {
next_key->objectid = (u64)-1;
next_key->type = (u8)-1;
next_key->offset = (u64)-1;
}
parent = eb;
while (1) {
struct btrfs_key first_key;
level = btrfs_header_level(parent);
BUG_ON(level < lowest_level);
ret = btrfs_bin_search(parent, &key, &slot);
if (ret < 0)
break;
if (ret && slot > 0)
slot--;
if (next_key && slot + 1 < btrfs_header_nritems(parent))
btrfs_node_key_to_cpu(parent, next_key, slot + 1);
old_bytenr = btrfs_node_blockptr(parent, slot);
blocksize = fs_info->nodesize;
old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
btrfs_node_key_to_cpu(parent, &first_key, slot);
if (level <= max_level) {
eb = path->nodes[level];
new_bytenr = btrfs_node_blockptr(eb,
path->slots[level]);
new_ptr_gen = btrfs_node_ptr_generation(eb,
path->slots[level]);
} else {
new_bytenr = 0;
new_ptr_gen = 0;
}
if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
ret = level;
break;
}
if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
memcmp_node_keys(parent, slot, path, level)) {
if (level <= lowest_level) {
ret = 0;
break;
}
eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
level - 1, &first_key);
if (IS_ERR(eb)) {
ret = PTR_ERR(eb);
break;
} else if (!extent_buffer_uptodate(eb)) {
ret = -EIO;
free_extent_buffer(eb);
break;
}
btrfs_tree_lock(eb);
if (cow) {
ret = btrfs_cow_block(trans, dest, eb, parent,
slot, &eb);
BUG_ON(ret);
}
btrfs_set_lock_blocking_write(eb);
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
parent = eb;
continue;
}
if (!cow) {
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
cow = 1;
goto again;
}
btrfs_node_key_to_cpu(path->nodes[level], &key,
path->slots[level]);
btrfs_release_path(path);
path->lowest_level = level;
ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
path->lowest_level = 0;
BUG_ON(ret);
/*
* Info qgroup to trace both subtrees.
*
* We must trace both trees.
* 1) Tree reloc subtree
* If not traced, we will leak data numbers
* 2) Fs subtree
* If not traced, we will double count old data
*
* We don't scan the subtree right now, but only record
* the swapped tree blocks.
* The real subtree rescan is delayed until we have new
* CoW on the subtree root node before transaction commit.
*/
ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
rc->block_group, parent, slot,
path->nodes[level], path->slots[level],
last_snapshot);
if (ret < 0)
break;
/*
* swap blocks in fs tree and reloc tree.
*/
btrfs_set_node_blockptr(parent, slot, new_bytenr);
btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
btrfs_mark_buffer_dirty(parent);
btrfs_set_node_blockptr(path->nodes[level],
path->slots[level], old_bytenr);
btrfs_set_node_ptr_generation(path->nodes[level],
path->slots[level], old_ptr_gen);
btrfs_mark_buffer_dirty(path->nodes[level]);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
blocksize, path->nodes[level]->start);
ref.skip_qgroup = true;
btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
ret = btrfs_inc_extent_ref(trans, &ref);
BUG_ON(ret);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
blocksize, 0);
ref.skip_qgroup = true;
btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
ret = btrfs_inc_extent_ref(trans, &ref);
BUG_ON(ret);
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
blocksize, path->nodes[level]->start);
btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
ref.skip_qgroup = true;
ret = btrfs_free_extent(trans, &ref);
BUG_ON(ret);
btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
blocksize, 0);
btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
ref.skip_qgroup = true;
ret = btrfs_free_extent(trans, &ref);
BUG_ON(ret);
btrfs_unlock_up_safe(path, 0);
ret = level;
break;
}
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
return ret;
}
/*
* helper to find next relocated block in reloc tree
*/
static noinline_for_stack
int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
int *level)
{
struct extent_buffer *eb;
int i;
u64 last_snapshot;
u32 nritems;
last_snapshot = btrfs_root_last_snapshot(&root->root_item);
for (i = 0; i < *level; i++) {
free_extent_buffer(path->nodes[i]);
path->nodes[i] = NULL;
}
for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
eb = path->nodes[i];
nritems = btrfs_header_nritems(eb);
while (path->slots[i] + 1 < nritems) {
path->slots[i]++;
if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
last_snapshot)
continue;
*level = i;
return 0;
}
free_extent_buffer(path->nodes[i]);
path->nodes[i] = NULL;
}
return 1;
}
/*
* walk down reloc tree to find relocated block of lowest level
*/
static noinline_for_stack
int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
int *level)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *eb = NULL;
int i;
u64 bytenr;
u64 ptr_gen = 0;
u64 last_snapshot;
u32 nritems;
last_snapshot = btrfs_root_last_snapshot(&root->root_item);
for (i = *level; i > 0; i--) {
struct btrfs_key first_key;
eb = path->nodes[i];
nritems = btrfs_header_nritems(eb);
while (path->slots[i] < nritems) {
ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
if (ptr_gen > last_snapshot)
break;
path->slots[i]++;
}
if (path->slots[i] >= nritems) {
if (i == *level)
break;
*level = i + 1;
return 0;
}
if (i == 1) {
*level = i;
return 0;
}
bytenr = btrfs_node_blockptr(eb, path->slots[i]);
btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
&first_key);
if (IS_ERR(eb)) {
return PTR_ERR(eb);
} else if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
return -EIO;
}
BUG_ON(btrfs_header_level(eb) != i - 1);
path->nodes[i - 1] = eb;
path->slots[i - 1] = 0;
}
return 1;
}
/*
* invalidate extent cache for file extents whose key in range of
* [min_key, max_key)
*/
static int invalidate_extent_cache(struct btrfs_root *root,
struct btrfs_key *min_key,
struct btrfs_key *max_key)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct inode *inode = NULL;
u64 objectid;
u64 start, end;
u64 ino;
objectid = min_key->objectid;
while (1) {
cond_resched();
iput(inode);
if (objectid > max_key->objectid)
break;
inode = find_next_inode(root, objectid);
if (!inode)
break;
ino = btrfs_ino(BTRFS_I(inode));
if (ino > max_key->objectid) {
iput(inode);
break;
}
objectid = ino + 1;
if (!S_ISREG(inode->i_mode))
continue;
if (unlikely(min_key->objectid == ino)) {
if (min_key->type > BTRFS_EXTENT_DATA_KEY)
continue;
if (min_key->type < BTRFS_EXTENT_DATA_KEY)
start = 0;
else {
start = min_key->offset;
WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
}
} else {
start = 0;
}
if (unlikely(max_key->objectid == ino)) {
if (max_key->type < BTRFS_EXTENT_DATA_KEY)
continue;
if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
end = (u64)-1;
} else {
if (max_key->offset == 0)
continue;
end = max_key->offset;
WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
end--;
}
} else {
end = (u64)-1;
}
/* the lock_extent waits for readpage to complete */
lock_extent(&BTRFS_I(inode)->io_tree, start, end);
btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
}
return 0;
}
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key)
{
while (level < BTRFS_MAX_LEVEL) {
if (!path->nodes[level])
break;
if (path->slots[level] + 1 <
btrfs_header_nritems(path->nodes[level])) {
btrfs_node_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
return 0;
}
level++;
}
return 1;
}
/*
* Insert current subvolume into reloc_control::dirty_subvol_roots
*/
static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_root *root)
{
struct btrfs_root *reloc_root = root->reloc_root;
struct btrfs_root_item *reloc_root_item;
/* @root must be a subvolume tree root with a valid reloc tree */
ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
ASSERT(reloc_root);
reloc_root_item = &reloc_root->root_item;
memset(&reloc_root_item->drop_progress, 0,
sizeof(reloc_root_item->drop_progress));
reloc_root_item->drop_level = 0;
btrfs_set_root_refs(reloc_root_item, 0);
btrfs_update_reloc_root(trans, root);
if (list_empty(&root->reloc_dirty_list)) {
btrfs_grab_root(root);
list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
}
}
static int clean_dirty_subvols(struct reloc_control *rc)
{
struct btrfs_root *root;
struct btrfs_root *next;
int ret = 0;
int ret2;
list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
reloc_dirty_list) {
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
/* Merged subvolume, cleanup its reloc root */
struct btrfs_root *reloc_root = root->reloc_root;
list_del_init(&root->reloc_dirty_list);
root->reloc_root = NULL;
/*
* Need barrier to ensure clear_bit() only happens after
* root->reloc_root = NULL. Pairs with have_reloc_root.
*/
smp_wmb();
clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
if (reloc_root) {
/*
* btrfs_drop_snapshot drops our ref we hold for
* ->reloc_root. If it fails however we must
* drop the ref ourselves.
*/
ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
if (ret2 < 0) {
btrfs_put_root(reloc_root);
if (!ret)
ret = ret2;
}
}
btrfs_put_root(root);
} else {
/* Orphan reloc tree, just clean it up */
ret2 = btrfs_drop_snapshot(root, 0, 1);
if (ret2 < 0) {
btrfs_put_root(root);
if (!ret)
ret = ret2;
}
}
}
return ret;
}
/*
* merge the relocated tree blocks in reloc tree with corresponding
* fs tree.
*/
static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct btrfs_key key;
struct btrfs_key next_key;
struct btrfs_trans_handle *trans = NULL;
struct btrfs_root *reloc_root;
struct btrfs_root_item *root_item;
struct btrfs_path *path;
struct extent_buffer *leaf;
int level;
int max_level;
int replaced = 0;
int ret;
int err = 0;
u32 min_reserved;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
reloc_root = root->reloc_root;
root_item = &reloc_root->root_item;
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_root_level(root_item);
atomic_inc(&reloc_root->node->refs);
path->nodes[level] = reloc_root->node;
path->slots[level] = 0;
} else {
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
level = root_item->drop_level;
BUG_ON(level == 0);
path->lowest_level = level;
ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0) {
btrfs_free_path(path);
return ret;
}
btrfs_node_key_to_cpu(path->nodes[level], &next_key,
path->slots[level]);
WARN_ON(memcmp(&key, &next_key, sizeof(key)));
btrfs_unlock_up_safe(path, 0);
}
/*
* In merge_reloc_root(), we modify the upper level pointer to swap the
* tree blocks between reloc tree and subvolume tree. Thus for tree
* block COW, we COW at most from level 1 to root level for each tree.
*
* Thus the needed metadata size is at most root_level * nodesize,
* and * 2 since we have two trees to COW.
*/
min_reserved = fs_info->nodesize * btrfs_root_level(root_item) * 2;
memset(&next_key, 0, sizeof(next_key));
while (1) {
ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
BTRFS_RESERVE_FLUSH_LIMIT);
if (ret) {
err = ret;
goto out;
}
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
trans = NULL;
goto out;
}
/*
* At this point we no longer have a reloc_control, so we can't
* depend on btrfs_init_reloc_root to update our last_trans.
*
* But that's ok, we started the trans handle on our
* corresponding fs_root, which means it's been added to the
* dirty list. At commit time we'll still call
* btrfs_update_reloc_root() and update our root item
* appropriately.
*/
reloc_root->last_trans = trans->transid;
trans->block_rsv = rc->block_rsv;
replaced = 0;
max_level = level;
ret = walk_down_reloc_tree(reloc_root, path, &level);
if (ret < 0) {
err = ret;
goto out;
}
if (ret > 0)
break;
if (!find_next_key(path, level, &key) &&
btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
ret = 0;
} else {
ret = replace_path(trans, rc, root, reloc_root, path,
&next_key, level, max_level);
}
if (ret < 0) {
err = ret;
goto out;
}
if (ret > 0) {
level = ret;
btrfs_node_key_to_cpu(path->nodes[level], &key,
path->slots[level]);
replaced = 1;
}
ret = walk_up_reloc_tree(reloc_root, path, &level);
if (ret > 0)
break;
BUG_ON(level == 0);
/*
* save the merging progress in the drop_progress.
* this is OK since root refs == 1 in this case.
*/
btrfs_node_key(path->nodes[level], &root_item->drop_progress,
path->slots[level]);
root_item->drop_level = level;
btrfs_end_transaction_throttle(trans);
trans = NULL;
btrfs_btree_balance_dirty(fs_info);
if (replaced && rc->stage == UPDATE_DATA_PTRS)
invalidate_extent_cache(root, &key, &next_key);
}
/*
* handle the case only one block in the fs tree need to be
* relocated and the block is tree root.
*/
leaf = btrfs_lock_root_node(root);
ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
btrfs_tree_unlock(leaf);
free_extent_buffer(leaf);
if (ret < 0)
err = ret;
out:
btrfs_free_path(path);
if (err == 0)
insert_dirty_subvol(trans, rc, root);
if (trans)
btrfs_end_transaction_throttle(trans);
btrfs_btree_balance_dirty(fs_info);
if (replaced && rc->stage == UPDATE_DATA_PTRS)
invalidate_extent_cache(root, &key, &next_key);
return err;
}
static noinline_for_stack
int prepare_to_merge(struct reloc_control *rc, int err)
{
struct btrfs_root *root = rc->extent_root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *reloc_root;
struct btrfs_trans_handle *trans;
LIST_HEAD(reloc_roots);
u64 num_bytes = 0;
int ret;
mutex_lock(&fs_info->reloc_mutex);
rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
rc->merging_rsv_size += rc->nodes_relocated * 2;
mutex_unlock(&fs_info->reloc_mutex);
again:
if (!err) {
num_bytes = rc->merging_rsv_size;
ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
BTRFS_RESERVE_FLUSH_ALL);
if (ret)
err = ret;
}
trans = btrfs_join_transaction(rc->extent_root);
if (IS_ERR(trans)) {
if (!err)
btrfs_block_rsv_release(fs_info, rc->block_rsv,
num_bytes, NULL);
return PTR_ERR(trans);
}
if (!err) {
if (num_bytes != rc->merging_rsv_size) {
btrfs_end_transaction(trans);
btrfs_block_rsv_release(fs_info, rc->block_rsv,
num_bytes, NULL);
goto again;
}
}
rc->merge_reloc_tree = 1;
while (!list_empty(&rc->reloc_roots)) {
reloc_root = list_entry(rc->reloc_roots.next,
struct btrfs_root, root_list);
list_del_init(&reloc_root->root_list);
root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
false);
BUG_ON(IS_ERR(root));
BUG_ON(root->reloc_root != reloc_root);
/*
* set reference count to 1, so btrfs_recover_relocation
* knows it should resumes merging
*/
if (!err)
btrfs_set_root_refs(&reloc_root->root_item, 1);
btrfs_update_reloc_root(trans, root);
list_add(&reloc_root->root_list, &reloc_roots);
btrfs_put_root(root);
}
list_splice(&reloc_roots, &rc->reloc_roots);
if (!err)
btrfs_commit_transaction(trans);
else
btrfs_end_transaction(trans);
return err;
}
static noinline_for_stack
void free_reloc_roots(struct list_head *list)
{
struct btrfs_root *reloc_root, *tmp;
list_for_each_entry_safe(reloc_root, tmp, list, root_list)
__del_reloc_root(reloc_root);
}
static noinline_for_stack
void merge_reloc_roots(struct reloc_control *rc)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct btrfs_root *root;
struct btrfs_root *reloc_root;
LIST_HEAD(reloc_roots);
int found = 0;
int ret = 0;
again:
root = rc->extent_root;
/*
* this serializes us with btrfs_record_root_in_transaction,
* we have to make sure nobody is in the middle of
* adding their roots to the list while we are
* doing this splice
*/
mutex_lock(&fs_info->reloc_mutex);
list_splice_init(&rc->reloc_roots, &reloc_roots);
mutex_unlock(&fs_info->reloc_mutex);
while (!list_empty(&reloc_roots)) {
found = 1;
reloc_root = list_entry(reloc_roots.next,
struct btrfs_root, root_list);
root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
false);
if (btrfs_root_refs(&reloc_root->root_item) > 0) {
BUG_ON(IS_ERR(root));
BUG_ON(root->reloc_root != reloc_root);
ret = merge_reloc_root(rc, root);
btrfs_put_root(root);
if (ret) {
if (list_empty(&reloc_root->root_list))
list_add_tail(&reloc_root->root_list,
&reloc_roots);
goto out;
}
} else {
if (!IS_ERR(root)) {
if (root->reloc_root == reloc_root) {
root->reloc_root = NULL;
btrfs_put_root(reloc_root);
}
clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
&root->state);
btrfs_put_root(root);
}
list_del_init(&reloc_root->root_list);
/* Don't forget to queue this reloc root for cleanup */
list_add_tail(&reloc_root->reloc_dirty_list,
&rc->dirty_subvol_roots);
}
}
if (found) {
found = 0;
goto again;
}
out:
if (ret) {
btrfs_handle_fs_error(fs_info, ret, NULL);
free_reloc_roots(&reloc_roots);
/* new reloc root may be added */
mutex_lock(&fs_info->reloc_mutex);
list_splice_init(&rc->reloc_roots, &reloc_roots);
mutex_unlock(&fs_info->reloc_mutex);
free_reloc_roots(&reloc_roots);
}
/*
* We used to have
*
* BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
*
* here, but it's wrong. If we fail to start the transaction in
* prepare_to_merge() we will have only 0 ref reloc roots, none of which
* have actually been removed from the reloc_root_tree rb tree. This is
* fine because we're bailing here, and we hold a reference on the root
* for the list that holds it, so these roots will be cleaned up when we
* do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
* will be cleaned up on unmount.
*
* The remaining nodes will be cleaned up by free_reloc_control.
*/
}
static void free_block_list(struct rb_root *blocks)
{
struct tree_block *block;
struct rb_node *rb_node;
while ((rb_node = rb_first(blocks))) {
block = rb_entry(rb_node, struct tree_block, rb_node);
rb_erase(rb_node, blocks);
kfree(block);
}
}
static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *reloc_root)
{
struct btrfs_fs_info *fs_info = reloc_root->fs_info;
struct btrfs_root *root;
int ret;
if (reloc_root->last_trans == trans->transid)
return 0;
root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
BUG_ON(IS_ERR(root));
BUG_ON(root->reloc_root != reloc_root);
ret = btrfs_record_root_in_trans(trans, root);
btrfs_put_root(root);
return ret;
}
static noinline_for_stack
struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_backref_node *node,
struct btrfs_backref_edge *edges[])
{
struct btrfs_backref_node *next;
struct btrfs_root *root;
int index = 0;
next = node;
while (1) {
cond_resched();
next = walk_up_backref(next, edges, &index);
root = next->root;
BUG_ON(!root);
BUG_ON(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state));
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
record_reloc_root_in_trans(trans, root);
break;
}
btrfs_record_root_in_trans(trans, root);
root = root->reloc_root;
if (next->new_bytenr != root->node->start) {
BUG_ON(next->new_bytenr);
BUG_ON(!list_empty(&next->list));
next->new_bytenr = root->node->start;
btrfs_put_root(next->root);
next->root = btrfs_grab_root(root);
ASSERT(next->root);
list_add_tail(&next->list,
&rc->backref_cache.changed);
mark_block_processed(rc, next);
break;
}
WARN_ON(1);
root = NULL;
next = walk_down_backref(edges, &index);
if (!next || next->level <= node->level)
break;
}
if (!root)
return NULL;
next = node;
/* setup backref node path for btrfs_reloc_cow_block */
while (1) {
rc->backref_cache.path[next->level] = next;
if (--index < 0)
break;
next = edges[index]->node[UPPER];
}
return root;
}
/*
* Select a tree root for relocation.
*
* Return NULL if the block is not shareable. We should use do_relocation() in
* this case.
*
* Return a tree root pointer if the block is shareable.
* Return -ENOENT if the block is root of reloc tree.
*/
static noinline_for_stack
struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
{
struct btrfs_backref_node *next;
struct btrfs_root *root;
struct btrfs_root *fs_root = NULL;
struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
int index = 0;
next = node;
while (1) {
cond_resched();
next = walk_up_backref(next, edges, &index);
root = next->root;
BUG_ON(!root);
/* No other choice for non-shareable tree */
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return root;
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
fs_root = root;
if (next != node)
return NULL;
next = walk_down_backref(edges, &index);
if (!next || next->level <= node->level)
break;
}
if (!fs_root)
return ERR_PTR(-ENOENT);
return fs_root;
}
static noinline_for_stack
u64 calcu_metadata_size(struct reloc_control *rc,
struct btrfs_backref_node *node, int reserve)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct btrfs_backref_node *next = node;
struct btrfs_backref_edge *edge;
struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
u64 num_bytes = 0;
int index = 0;
BUG_ON(reserve && node->processed);
while (next) {
cond_resched();
while (1) {
if (next->processed && (reserve || next != node))
break;
num_bytes += fs_info->nodesize;
if (list_empty(&next->upper))
break;
edge = list_entry(next->upper.next,
struct btrfs_backref_edge, list[LOWER]);
edges[index++] = edge;
next = edge->node[UPPER];
}
next = walk_down_backref(edges, &index);
}
return num_bytes;
}
static int reserve_metadata_space(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_backref_node *node)
{
struct btrfs_root *root = rc->extent_root;
struct btrfs_fs_info *fs_info = root->fs_info;
u64 num_bytes;
int ret;
u64 tmp;
num_bytes = calcu_metadata_size(rc, node, 1) * 2;
trans->block_rsv = rc->block_rsv;
rc->reserved_bytes += num_bytes;
/*
* We are under a transaction here so we can only do limited flushing.
* If we get an enospc just kick back -EAGAIN so we know to drop the
* transaction and try to refill when we can flush all the things.
*/
ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
BTRFS_RESERVE_FLUSH_LIMIT);
if (ret) {
tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
while (tmp <= rc->reserved_bytes)
tmp <<= 1;
/*
* only one thread can access block_rsv at this point,
* so we don't need hold lock to protect block_rsv.
* we expand more reservation size here to allow enough
* space for relocation and we will return earlier in
* enospc case.
*/
rc->block_rsv->size = tmp + fs_info->nodesize *
RELOCATION_RESERVED_NODES;
return -EAGAIN;
}
return 0;
}
/*
* relocate a block tree, and then update pointers in upper level
* blocks that reference the block to point to the new location.
*
* if called by link_to_upper, the block has already been relocated.
* in that case this function just updates pointers.
*/
static int do_relocation(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_backref_node *node,
struct btrfs_key *key,
struct btrfs_path *path, int lowest)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct btrfs_backref_node *upper;
struct btrfs_backref_edge *edge;
struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
struct btrfs_root *root;
struct extent_buffer *eb;
u32 blocksize;
u64 bytenr;
u64 generation;
int slot;
int ret;
int err = 0;
BUG_ON(lowest && node->eb);
path->lowest_level = node->level + 1;
rc->backref_cache.path[node->level] = node;
list_for_each_entry(edge, &node->upper, list[LOWER]) {
struct btrfs_key first_key;
struct btrfs_ref ref = { 0 };
cond_resched();
upper = edge->node[UPPER];
root = select_reloc_root(trans, rc, upper, edges);
BUG_ON(!root);
if (upper->eb && !upper->locked) {
if (!lowest) {
ret = btrfs_bin_search(upper->eb, key, &slot);
if (ret < 0) {
err = ret;
goto next;
}
BUG_ON(ret);
bytenr = btrfs_node_blockptr(upper->eb, slot);
if (node->eb->start == bytenr)
goto next;
}
btrfs_backref_drop_node_buffer(upper);
}
if (!upper->eb) {
ret = btrfs_search_slot(trans, root, key, path, 0, 1);
if (ret) {
if (ret < 0)
err = ret;
else
err = -ENOENT;
btrfs_release_path(path);
break;
}
if (!upper->eb) {
upper->eb = path->nodes[upper->level];
path->nodes[upper->level] = NULL;
} else {
BUG_ON(upper->eb != path->nodes[upper->level]);
}
upper->locked = 1;
path->locks[upper->level] = 0;
slot = path->slots[upper->level];
btrfs_release_path(path);
} else {
ret = btrfs_bin_search(upper->eb, key, &slot);
if (ret < 0) {
err = ret;
goto next;
}
BUG_ON(ret);
}
bytenr = btrfs_node_blockptr(upper->eb, slot);
if (lowest) {
if (bytenr != node->bytenr) {
btrfs_err(root->fs_info,
"lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
bytenr, node->bytenr, slot,
upper->eb->start);
err = -EIO;
goto next;
}
} else {
if (node->eb->start == bytenr)
goto next;
}
blocksize = root->fs_info->nodesize;
generation = btrfs_node_ptr_generation(upper->eb, slot);
btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
eb = read_tree_block(fs_info, bytenr, generation,
upper->level - 1, &first_key);
if (IS_ERR(eb)) {
err = PTR_ERR(eb);
goto next;
} else if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
err = -EIO;
goto next;
}
btrfs_tree_lock(eb);
btrfs_set_lock_blocking_write(eb);
if (!node->eb) {
ret = btrfs_cow_block(trans, root, eb, upper->eb,
slot, &eb);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
if (ret < 0) {
err = ret;
goto next;
}
BUG_ON(node->eb != eb);
} else {
btrfs_set_node_blockptr(upper->eb, slot,
node->eb->start);
btrfs_set_node_ptr_generation(upper->eb, slot,
trans->transid);
btrfs_mark_buffer_dirty(upper->eb);
btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
node->eb->start, blocksize,
upper->eb->start);
ref.real_root = root->root_key.objectid;
btrfs_init_tree_ref(&ref, node->level,
btrfs_header_owner(upper->eb));
ret = btrfs_inc_extent_ref(trans, &ref);
BUG_ON(ret);
ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
BUG_ON(ret);
}
next:
if (!upper->pending)
btrfs_backref_drop_node_buffer(upper);
else
btrfs_backref_unlock_node_buffer(upper);
if (err)
break;
}
if (!err && node->pending) {
btrfs_backref_drop_node_buffer(node);
list_move_tail(&node->list, &rc->backref_cache.changed);
node->pending = 0;
}
path->lowest_level = 0;
BUG_ON(err == -ENOSPC);
return err;
}
static int link_to_upper(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_backref_node *node,
struct btrfs_path *path)
{
struct btrfs_key key;
btrfs_node_key_to_cpu(node->eb, &key, 0);
return do_relocation(trans, rc, node, &key, path, 0);
}
static int finish_pending_nodes(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_path *path, int err)
{
LIST_HEAD(list);
struct btrfs_backref_cache *cache = &rc->backref_cache;
struct btrfs_backref_node *node;
int level;
int ret;
for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
while (!list_empty(&cache->pending[level])) {
node = list_entry(cache->pending[level].next,
struct btrfs_backref_node, list);
list_move_tail(&node->list, &list);
BUG_ON(!node->pending);
if (!err) {
ret = link_to_upper(trans, rc, node, path);
if (ret < 0)
err = ret;
}
}
list_splice_init(&list, &cache->pending[level]);
}
return err;
}
/*
* mark a block and all blocks directly/indirectly reference the block
* as processed.
*/
static void update_processed_blocks(struct reloc_control *rc,
struct btrfs_backref_node *node)
{
struct btrfs_backref_node *next = node;
struct btrfs_backref_edge *edge;
struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
int index = 0;
while (next) {
cond_resched();
while (1) {
if (next->processed)
break;
mark_block_processed(rc, next);
if (list_empty(&next->upper))
break;
edge = list_entry(next->upper.next,
struct btrfs_backref_edge, list[LOWER]);
edges[index++] = edge;
next = edge->node[UPPER];
}
next = walk_down_backref(edges, &index);
}
}
static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
{
u32 blocksize = rc->extent_root->fs_info->nodesize;
if (test_range_bit(&rc->processed_blocks, bytenr,
bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
return 1;
return 0;
}
static int get_tree_block_key(struct btrfs_fs_info *fs_info,
struct tree_block *block)
{
struct extent_buffer *eb;
eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
block->level, NULL);
if (IS_ERR(eb)) {
return PTR_ERR(eb);
} else if (!extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
return -EIO;
}
if (block->level == 0)
btrfs_item_key_to_cpu(eb, &block->key, 0);
else
btrfs_node_key_to_cpu(eb, &block->key, 0);
free_extent_buffer(eb);
block->key_ready = 1;
return 0;
}
/*
* helper function to relocate a tree block
*/
static int relocate_tree_block(struct btrfs_trans_handle *trans,
struct reloc_control *rc,
struct btrfs_backref_node *node,
struct btrfs_key *key,
struct btrfs_path *path)
{
struct btrfs_root *root;
int ret = 0;
if (!node)
return 0;
/*
* If we fail here we want to drop our backref_node because we are going
* to start over and regenerate the tree for it.
*/
ret = reserve_metadata_space(trans, rc, node);
if (ret)
goto out;
BUG_ON(node->processed);
root = select_one_root(node);
if (root == ERR_PTR(-ENOENT)) {
update_processed_blocks(rc, node);
goto out;
}
if (root) {
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
BUG_ON(node->new_bytenr);
BUG_ON(!list_empty(&node->list));
btrfs_record_root_in_trans(trans, root);
root = root->reloc_root;
node->new_bytenr = root->node->start;
btrfs_put_root(node->root);
node->root = btrfs_grab_root(root);
ASSERT(node->root);
list_add_tail(&node->list, &rc->backref_cache.changed);
} else {
path->lowest_level = node->level;
ret = btrfs_search_slot(trans, root, key, path, 0, 1);
btrfs_release_path(path);
if (ret > 0)
ret = 0;
}
if (!ret)
update_processed_blocks(rc, node);
} else {
ret = do_relocation(trans, rc, node, key, path, 1);
}
out:
if (ret || node->level == 0 || node->cowonly)
btrfs_backref_cleanup_node(&rc->backref_cache, node);
return ret;
}
/*
* relocate a list of blocks
*/
static noinline_for_stack
int relocate_tree_blocks(struct btrfs_trans_handle *trans,
struct reloc_control *rc, struct rb_root *blocks)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
struct btrfs_backref_node *node;
struct btrfs_path *path;
struct tree_block *block;
struct tree_block *next;
int ret;
int err = 0;
path = btrfs_alloc_path();
if (!path) {
err = -ENOMEM;
goto out_free_blocks;
}
/* Kick in readahead for tree blocks with missing keys */
rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
if (!block->key_ready)
readahead_tree_block(fs_info, block->bytenr);
}
/* Get first keys */
rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
if (!block->key_ready) {
err = get_tree_block_key(fs_info, block);
if (err)
goto out_free_path;
}
}
/* Do tree relocation */
rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
node = build_backref_tree(rc, &block->key,
block->level, block->bytenr);
if (IS_ERR(node)) {
err = PTR_ERR(node);
goto out;
}
ret = relocate_tree_block(trans, rc, node, &block->key,
path);
if (ret < 0) {
err = ret;
break;
}
}
out:
err = finish_pending_nodes(trans, rc, path, err);
out_free_path:
btrfs_free_path(path);
out_free_blocks:
free_block_list(blocks);
return err;
}
static noinline_for_stack int prealloc_file_extent_cluster(
struct btrfs_inode *inode,
struct file_extent_cluster *cluster)
{
u64 alloc_hint = 0;
u64 start;
u64 end;
u64 offset = inode->index_cnt;
u64 num_bytes;
int nr;
int ret = 0;
u64 prealloc_start = cluster->start - offset;
u64 prealloc_end = cluster->end - offset;
u64 cur_offset = prealloc_start;
BUG_ON(cluster->start != cluster->boundary[0]);
ret = btrfs_alloc_data_chunk_ondemand(inode,
prealloc_end + 1 - prealloc_start);
if (ret)
return ret;
inode_lock(&inode->vfs_inode);
for (nr = 0; nr < cluster->nr; nr++) {
start = cluster->boundary[nr] - offset;
if (nr + 1 < cluster->nr)
end = cluster->boundary[nr + 1] - 1 - offset;
else
end = cluster->end - offset;
lock_extent(&inode->io_tree, start, end);
num_bytes = end + 1 - start;
ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
num_bytes, num_bytes,
end + 1, &alloc_hint);
cur_offset = end + 1;
unlock_extent(&inode->io_tree, start, end);
if (ret)
break;
}
inode_unlock(&inode->vfs_inode);
if (cur_offset < prealloc_end)
btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
prealloc_end + 1 - cur_offset);
return ret;
}
static noinline_for_stack
int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
u64 block_start)
{
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct extent_map *em;
int ret = 0;
em = alloc_extent_map();
if (!em)
return -ENOMEM;
em->start = start;
em->len = end + 1 - start;
em->block_len = em->len;
em->block_start = block_start;
set_bit(EXTENT_FLAG_PINNED, &em->flags);
lock_extent(&BTRFS_I(inode)->io_tree, start, end);
while (1) {
write_lock(&em_tree->lock);
ret = add_extent_mapping(em_tree, em, 0);
write_unlock(&em_tree->lock);
if (ret != -EEXIST) {
free_extent_map(em);
break;
}
btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
}
unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
return ret;
}
/*
* Allow error injection to test balance cancellation
*/
int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
{
return atomic_read(&fs_info->balance_cancel_req) ||
fatal_signal_pending(current);
}
ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
static int relocate_file_extent_cluster(struct inode *inode,
struct file_extent_cluster *cluster)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
u64 page_start;
u64 page_end;
u64 offset = BTRFS_I(inode)->index_cnt;
unsigned long index;
unsigned long last_index;
struct page *page;
struct file_ra_state *ra;
gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
int nr = 0;
int ret = 0;
if (!cluster->nr)
return 0;
ra = kzalloc(sizeof(*ra), GFP_NOFS);
if (!ra)
return -ENOMEM;
ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
if (ret)
goto out;
file_ra_state_init(ra, inode->i_mapping);
ret = setup_extent_mapping(inode, cluster->start - offset,
cluster->end - offset, cluster->start);
if (ret)
goto out;
index = (cluster->start - offset) >> PAGE_SHIFT;
last_index = (cluster->end - offset) >> PAGE_SHIFT;
while (index <= last_index) {
ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
PAGE_SIZE);
if (ret)
goto out;
page = find_lock_page(inode->i_mapping, index);
if (!page) {
page_cache_sync_readahead(inode->i_mapping,
ra, NULL, index,
last_index + 1 - index);
page = find_or_create_page(inode->i_mapping, index,
mask);
if (!page) {
btrfs_delalloc_release_metadata(BTRFS_I(inode),
PAGE_SIZE, true);
btrfs_delalloc_release_extents(BTRFS_I(inode),
PAGE_SIZE);
ret = -ENOMEM;
goto out;
}
}
if (PageReadahead(page)) {
page_cache_async_readahead(inode->i_mapping,
ra, NULL, page, index,
last_index + 1 - index);
}
if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
put_page(page);
btrfs_delalloc_release_metadata(BTRFS_I(inode),
PAGE_SIZE, true);
btrfs_delalloc_release_extents(BTRFS_I(inode),
PAGE_SIZE);
ret = -EIO;
goto out;
}
}
page_start = page_offset(page);
page_end = page_start + PAGE_SIZE - 1;
lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
set_page_extent_mapped(page);
if (nr < cluster->nr &&
page_start + offset == cluster->boundary[nr]) {
set_extent_bits(&BTRFS_I(inode)->io_tree,
page_start, page_end,
EXTENT_BOUNDARY);
nr++;
}
ret = btrfs_set_extent_delalloc(BTRFS_I(inode), page_start,
page_end, 0, NULL);
if (ret) {
unlock_page(page);
put_page(page);
btrfs_delalloc_release_metadata(BTRFS_I(inode),
PAGE_SIZE, true);