// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/blkdev.h>
#include <linux/sort.h>
#include <linux/rcupdate.h>
#include <linux/kthread.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/percpu_counter.h>
#include <linux/lockdep.h>
#include <linux/crc32c.h>
#include "ctree.h"
#include "extent-tree.h"
#include "transaction.h"
#include "disk-io.h"
#include "print-tree.h"
#include "volumes.h"
#include "raid56.h"
#include "locking.h"
#include "free-space-cache.h"
#include "free-space-tree.h"
#include "qgroup.h"
#include "ref-verify.h"
#include "space-info.h"
#include "block-rsv.h"
#include "discard.h"
#include "zoned.h"
#include "dev-replace.h"
#include "fs.h"
#include "accessors.h"
#include "root-tree.h"
#include "file-item.h"
#include "orphan.h"
#include "tree-checker.h"
#include "raid-stripe-tree.h"
#undef SCRAMBLE_DELAYED_REFS
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extra_op);
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei);
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod, u64 oref_root);
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op);
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key);
static int block_group_bits(struct btrfs_block_group *cache, u64 bits)
{
return (cache->flags & bits) == bits;
}
/* simple helper to search for an existing data extent at a given offset */
int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
{
struct btrfs_root *root = btrfs_extent_root(fs_info, start);
int ret;
struct btrfs_key key;
struct btrfs_path *path;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = start;
key.offset = len;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
btrfs_free_path(path);
return ret;
}
/*
* helper function to lookup reference count and flags of a tree block.
*
* the head node for delayed ref is used to store the sum of all the
* reference count modifications queued up in the rbtree. the head
* node may also store the extent flags to set. This way you can check
* to see what the reference count and extent flags would be if all of
* the delayed refs are not processed.
*/
int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 offset, int metadata, u64 *refs, u64 *flags,
u64 *owning_root)
{
struct btrfs_root *extent_root;
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_path *path;
struct btrfs_key key;
u64 num_refs;
u64 extent_flags;
u64 owner = 0;
int ret;
/*
* If we don't have skinny metadata, don't bother doing anything
* different
*/
if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
offset = fs_info->nodesize;
metadata = 0;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
search_again:
key.objectid = bytenr;
key.offset = offset;
if (metadata)
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
extent_root = btrfs_extent_root(fs_info, bytenr);
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out_free;
if (ret > 0 && key.type == BTRFS_METADATA_ITEM_KEY) {
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == fs_info->nodesize)
ret = 0;
}
}
if (ret == 0) {
struct extent_buffer *leaf = path->nodes[0];
struct btrfs_extent_item *ei;
const u32 item_size = btrfs_item_size(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EUCLEAN;
btrfs_err(fs_info,
"unexpected extent item size, has %u expect >= %zu",
item_size, sizeof(*ei));
btrfs_abort_transaction(trans, ret);
goto out_free;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
num_refs = btrfs_extent_refs(leaf, ei);
if (unlikely(num_refs == 0)) {
ret = -EUCLEAN;
btrfs_err(fs_info,
"unexpected zero reference count for extent item (%llu %u %llu)",
key.objectid, key.type, key.offset);
btrfs_abort_transaction(trans, ret);
goto out_free;
}
extent_flags = btrfs_extent_flags(leaf, ei);
owner = btrfs_get_extent_owner_root(fs_info, leaf, path->slots[0]);
} else {
num_refs = 0;
extent_flags = 0;
ret = 0;
}
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and try
* again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
goto search_again;
}
spin_lock(&head->lock);
if (head->extent_op && head->extent_op->update_flags)
extent_flags |= head->extent_op->flags_to_set;
num_refs += head->ref_mod;
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
}
spin_unlock(&delayed_refs->lock);
WARN_ON(num_refs == 0);
if (refs)
*refs = num_refs;
if (flags)
*flags = extent_flags;
if (owning_root)
*owning_root = owner;
out_free:
btrfs_free_path(path);
return ret;
}
/*
* Back reference rules. Back refs have three main goals:
*
* 1) differentiate between all holders of references to an extent so that
* when a reference is dropped we can make sure it was a valid reference
* before freeing the extent.
*
* 2) Provide enough information to quickly find the holders of an extent
* if we notice a given block is corrupted or bad.
*
* 3) Make it easy to migrate blocks for FS shrinking or storage pool
* maintenance. This is actually the same as #2, but with a slightly
* different use case.
*
* There are two kinds of back refs. The implicit back refs is optimized
* for pointers in non-shared tree blocks. For a given pointer in a block,
* back refs of this kind provide information about the block's owner tree
* and the pointer's key. These information allow us to find the block by
* b-tree searching. The full back refs is for pointers in tree blocks not
* referenced by their owner trees. The location of tree block is recorded
* in the back refs. Actually the full back refs is generic, and can be
* used in all cases the implicit back refs is used. The major shortcoming
* of the full back refs is its overhead. Every time a tree block gets
* COWed, we have to update back refs entry for all pointers in it.
*
* For a newly allocated tree block, we use implicit back refs for
* pointers in it. This means most tree related operations only involve
* implicit back refs. For a tree block created in old transaction, the
* only way to drop a reference to it is COW it. So we can detect the
* event that tree block loses its owner tree's reference and do the
* back refs conversion.
*
* When a tree block is COWed through a tree, there are four cases:
*
* The reference count of the block is one and the tree is the block's
* owner tree. Nothing to do in this case.
*
* The reference count of the block is one and the tree is not the
* block's owner tree. In this case, full back refs is used for pointers
* in the block. Remove these full back refs, add implicit back refs for
* every pointers in the new block.
*
* The reference count of the block is greater than one and the tree is
* the block's owner tree. In this case, implicit back refs is used for
* pointers in the block. Add full back refs for every pointers in the
* block, increase lower level extents' reference counts. The original
* implicit back refs are entailed to the new block.
*
* The reference count of the block is greater than one and the tree is
* not the block's owner tree. Add implicit back refs for every pointer in
* the new block, increase lower level extents' reference count.
*
* Back Reference Key composing:
*
* The key objectid corresponds to the first byte in the extent,
* The key type is used to differentiate between types of back refs.
* There are different meanings of the key offset for different types
* of back refs.
*
* File extents can be referenced by:
*
* - multiple snapshots, subvolumes, or different generations in one subvol
* - different files inside a single subvolume
* - different offsets inside a file (bookend extents in file.c)
*
* The extent ref structure for the implicit back refs has fields for:
*
* - Objectid of the subvolume root
* - objectid of the file holding the reference
* - original offset in the file
* - how many bookend extents
*
* The key offset for the implicit back refs is hash of the first
* three fields.
*
* The extent ref structure for the full back refs has field for:
*
* - number of pointers in the tree leaf
*
* The key offset for the implicit back refs is the first byte of
* the tree leaf
*
* When a file extent is allocated, The implicit back refs is used.
* the fields are filled in:
*
* (root_key.objectid, inode objectid, offset in file, 1)
*
* When a file extent is removed file truncation, we find the
* corresponding implicit back refs and check the following fields:
*
* (btrfs_header_owner(leaf), inode objectid, offset in file)
*
* Btree extents can be referenced by:
*
* - Different subvolumes
*
* Both the implicit back refs and the full back refs for tree blocks
* only consist of key. The key offset for the implicit back refs is
* objectid of block's owner tree. The key offset for the full back refs
* is the first byte of parent block.
*
* When implicit back refs is used, information about the lowest key and
* level of the tree block are required. These information are stored in
* tree block info structure.
*/
/*
* is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
* is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
* is_data == BTRFS_REF_TYPE_ANY, either type is OK.
*/
int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
struct btrfs_extent_inline_ref *iref,
enum btrfs_inline_ref_type is_data)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
int type = btrfs_extent_inline_ref_type(eb, iref);
u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
return type;
}
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
type == BTRFS_SHARED_BLOCK_REF_KEY ||
type == BTRFS_SHARED_DATA_REF_KEY ||
type == BTRFS_EXTENT_DATA_REF_KEY) {
if (is_data == BTRFS_REF_TYPE_BLOCK) {
if (type == BTRFS_TREE_BLOCK_REF_KEY)
return type;
if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
ASSERT(fs_info);
/*
* Every shared one has parent tree block,
* which must be aligned to sector size.
*/
if (offset && IS_ALIGNED(offset, fs_info->sectorsize))
return type;
}
} else if (is_data == BTRFS_REF_TYPE_DATA) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
return type;
if (type == BTRFS_SHARED_DATA_REF_KEY) {
ASSERT(fs_info);
/*
* Every shared one has parent tree block,
* which must be aligned to sector size.
*/
if (offset &&
IS_ALIGNED(offset, fs_info->sectorsize))
return type;
}
} else {
ASSERT(is_data == BTRFS_REF_TYPE_ANY);
return type;
}
}
WARN_ON(1);
btrfs_print_leaf(eb);
btrfs_err(fs_info,
"eb %llu iref 0x%lx invalid extent inline ref type %d",
eb->start, (unsigned long)iref, type);
return BTRFS_REF_TYPE_INVALID;
}
u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
{
u32 high_crc = ~(u32)0;
u32 low_crc = ~(u32)0;
__le64 lenum;
lenum = cpu_to_le64(root_objectid);
high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(owner);
low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
lenum = cpu_to_le64(offset);
low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
return ((u64)high_crc << 31) ^ (u64)low_crc;
}
static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref)
{
return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
btrfs_extent_data_ref_objectid(leaf, ref),
btrfs_extent_data_ref_offset(leaf, ref));
}
static int match_extent_data_ref(struct extent_buffer *leaf,
struct btrfs_extent_data_ref *ref,
u64 root_objectid, u64 owner, u64 offset)
{
if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
return 0;
return 1;
}
static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid,
u64 owner, u64 offset)
{
struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
struct btrfs_key key;
struct btrfs_extent_data_ref *ref;
struct extent_buffer *leaf;
u32 nritems;
int recow;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(root_objectid,
owner, offset);
}
again:
recow = 0;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
return ret;
if (parent) {
if (ret)
return -ENOENT;
return 0;
}
ret = -ENOENT;
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
while (1) {
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret) {
if (ret > 0)
return -ENOENT;
return ret;
}
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr ||
key.type != BTRFS_EXTENT_DATA_REF_KEY)
goto fail;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, root_objectid,
owner, offset)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
ret = 0;
break;
}
path->slots[0]++;
}
fail:
return ret;
}
static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_delayed_ref_node *node,
u64 bytenr)
{
struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
struct btrfs_key key;
struct extent_buffer *leaf;
u64 owner = btrfs_delayed_ref_owner(node);
u64 offset = btrfs_delayed_ref_offset(node);
u32 size;
u32 num_refs;
int ret;
key.objectid = bytenr;
if (node->parent) {
key.type = BTRFS_SHARED_DATA_REF_KEY;
key.offset = node->parent;
size = sizeof(struct btrfs_shared_data_ref);
} else {
key.type = BTRFS_EXTENT_DATA_REF_KEY;
key.offset = hash_extent_data_ref(node->ref_root, owner, offset);
size = sizeof(struct btrfs_extent_data_ref);
}
ret = btrfs_insert_empty_item(trans, root, path, &key, size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
if (node->parent) {
struct btrfs_shared_data_ref *ref;
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
if (ret == 0) {
btrfs_set_shared_data_ref_count(leaf, ref, node->ref_mod);
} else {
num_refs = btrfs_shared_data_ref_count(leaf, ref);
num_refs += node->ref_mod;
btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
}
} else {
struct btrfs_extent_data_ref *ref;
while (ret == -EEXIST) {
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (match_extent_data_ref(leaf, ref, node->ref_root,
owner, offset))
break;
btrfs_release_path(path);
key.offset++;
ret = btrfs_insert_empty_item(trans, root, path, &key,
size);
if (ret && ret != -EEXIST)
goto fail;
leaf = path->nodes[0];
}
ref = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
if (ret == 0) {
btrfs_set_extent_data_ref_root(leaf, ref, node->ref_root);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, node->ref_mod);
} else {
num_refs = btrfs_extent_data_ref_count(leaf, ref);
num_refs += node->ref_mod;
btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
}
}
btrfs_mark_buffer_dirty(trans, leaf);
ret = 0;
fail:
btrfs_release_path(path);
return ret;
}
static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
int refs_to_drop)
{
struct btrfs_key key;
struct btrfs_extent_data_ref *ref1 = NULL;
struct btrfs_shared_data_ref *ref2 = NULL;
struct extent_buffer *leaf;
u32 num_refs = 0;
int ret = 0;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else {
btrfs_err(trans->fs_info,
"unrecognized backref key (%llu %u %llu)",
key.objectid, key.type, key.offset);
btrfs_abort_transaction(trans, -EUCLEAN);
return -EUCLEAN;
}
BUG_ON(num_refs < refs_to_drop);
num_refs -= refs_to_drop;
if (num_refs == 0) {
ret = btrfs_del_item(trans, root, path);
} else {
if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
btrfs_mark_buffer_dirty(trans, leaf);
}
return ret;
}
static noinline u32 extent_data_ref_count(struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref)
{
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref1;
struct btrfs_shared_data_ref *ref2;
u32 num_refs = 0;
int type;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (iref) {
/*
* If type is invalid, we should have bailed out earlier than
* this call.
*/
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
ASSERT(type != BTRFS_REF_TYPE_INVALID);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else {
ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
}
} else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
ref1 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_data_ref);
num_refs = btrfs_extent_data_ref_count(leaf, ref1);
} else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
ref2 = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_shared_data_ref);
num_refs = btrfs_shared_data_ref_count(leaf, ref2);
} else {
WARN_ON(1);
}
return num_refs;
}
static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 parent,
u64 root_objectid)
{
struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = root_objectid;
}
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
return ret;
}
static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_delayed_ref_node *node,
u64 bytenr)
{
struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
struct btrfs_key key;
int ret;
key.objectid = bytenr;
if (node->parent) {
key.type = BTRFS_SHARED_BLOCK_REF_KEY;
key.offset = node->parent;
} else {
key.type = BTRFS_TREE_BLOCK_REF_KEY;
key.offset = node->ref_root;
}
ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
btrfs_release_path(path);
return ret;
}
static inline int extent_ref_type(u64 parent, u64 owner)
{
int type;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
if (parent > 0)
type = BTRFS_SHARED_BLOCK_REF_KEY;
else
type = BTRFS_TREE_BLOCK_REF_KEY;
} else {
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
}
return type;
}
static int find_next_key(struct btrfs_path *path, int level,
struct btrfs_key *key)
{
for (; level < BTRFS_MAX_LEVEL; level++) {
if (!path->nodes[level])
break;
if (path->slots[level] + 1 >=
btrfs_header_nritems(path->nodes[level]))
continue;
if (level == 0)
btrfs_item_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
else
btrfs_node_key_to_cpu(path->nodes[level], key,
path->slots[level] + 1);
return 0;
}
return 1;
}
/*
* look for inline back ref. if back ref is found, *ref_ret is set
* to the address of inline back ref, and 0 is returned.
*
* if back ref isn't found, *ref_ret is set to the address where it
* should be inserted, and -ENOENT is returned.
*
* if insert is true and there are too many inline back refs, the path
* points to the extent item, and -EAGAIN is returned.
*
* NOTE: inline back refs are ordered in the same way that back ref
* items in the tree are ordered.
*/
static noinline_for_stack
int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int insert)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);
struct btrfs_key key;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
u64 flags;
u64 item_size;
unsigned long ptr;
unsigned long end;
int extra_size;
int type;
int want;
int ret;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
int needed;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
want = extent_ref_type(parent, owner);
if (insert) {
extra_size = btrfs_extent_inline_ref_size(want);
path->search_for_extension = 1;
path->keep_locks = 1;
} else
extra_size = -1;
/*
* Owner is our level, so we can just add one to get the level for the
* block we are interested in.
*/
if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner;
}
again:
ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
if (ret < 0)
goto out;
/*
* We may be a newly converted file system which still has the old fat
* extent entries for metadata, so try and see if we have one of those.
*/
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
if (path->slots[0]) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret) {
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
goto again;
}
}
if (ret && !insert) {
ret = -ENOENT;
goto out;
} else if (WARN_ON(ret)) {
btrfs_print_leaf(path->nodes[0]);
btrfs_err(fs_info,
"extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
bytenr, num_bytes, parent, root_objectid, owner,
offset);
ret = -EUCLEAN;
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EUCLEAN;
btrfs_err(fs_info,
"unexpected extent item size, has %llu expect >= %zu",
item_size, sizeof(*ei));
btrfs_abort_transaction(trans, ret);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
flags = btrfs_extent_flags(leaf, ei);
ptr = (unsigned long)(ei + 1);
end = (unsigned long)ei + item_size;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
ptr += sizeof(struct btrfs_tree_block_info);
BUG_ON(ptr > end);
}
if (owner >= BTRFS_FIRST_FREE_OBJECTID)
needed = BTRFS_REF_TYPE_DATA;
else
needed = BTRFS_REF_TYPE_BLOCK;
ret = -ENOENT;
while (ptr < end) {
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
ptr += btrfs_extent_inline_ref_size(type);
continue;
}
if (type == BTRFS_REF_TYPE_INVALID) {
ret = -EUCLEAN;
goto out;
}
if (want < type)
break;
if (want > type) {
ptr += btrfs_extent_inline_ref_size(type);
continue;
}
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (match_extent_data_ref(leaf, dref, root_objectid,
owner, offset)) {
ret = 0;
break;
}
if (hash_extent_data_ref_item(leaf, dref) <
hash_extent_data_ref(root_objectid, owner, offset))
break;
} else {
u64 ref_offset;
ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
if (parent > 0) {
if (parent == ref_offset) {
ret = 0;
break;
}
if (ref_offset < parent)
break;
} else {
if (root_objectid == ref_offset) {
ret = 0;
break;
}
if (ref_offset < root_objectid)
break;
}
}
ptr += btrfs_extent_inline_ref_size(type);
}
if (unlikely(ptr > end)) {
ret = -EUCLEAN;
btrfs_print_leaf(path->nodes[0]);
btrfs_crit(fs_info,
"overrun extent record at slot %d while looking for inline extent for root %llu owner %llu offset %llu parent %llu",
path->slots[0], root_objectid, owner, offset, parent);
goto out;
}
if (ret == -ENOENT && insert) {
if (item_size + extra_size >=
BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
ret = -EAGAIN;
goto out;
}
/*
* To add new inline back ref, we have to make sure
* there is no corresponding back ref item.
* For simplicity, we just do not add new inline back
* ref if there is any kind of item for this block
*/
if (find_next_key(path, 0, &key) == 0 &&
key.objectid == bytenr &&
key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
ret = -EAGAIN;
goto out;
}
}
*ref_ret = (struct btrfs_extent_inline_ref *)ptr;
out:
if (insert) {
path->keep_locks = 0;
path->search_for_extension = 0;
btrfs_unlock_up_safe(path, 1);
}
return ret;
}
/*
* helper to add new inline back ref
*/
static noinline_for_stack
void setup_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
u64 parent, u64 root_objectid,
u64 owner, u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
unsigned long ptr;
unsigned long end;
unsigned long item_offset;
u64 refs;
int size;
int type;
leaf = path->nodes[0];
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
item_offset = (unsigned long)iref - (unsigned long)ei;
type = extent_ref_type(parent, owner);
size = btrfs_extent_inline_ref_size(type);
btrfs_extend_item(trans, path, size);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
refs += refs_to_add;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
ptr = (unsigned long)ei + item_offset;
end = (unsigned long)ei + btrfs_item_size(leaf, path->slots[0]);
if (ptr < end - size)
memmove_extent_buffer(leaf, ptr + size, ptr,
end - size - ptr);
iref = (struct btrfs_extent_inline_ref *)ptr;
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
struct btrfs_extent_data_ref *dref;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
btrfs_set_extent_data_ref_offset(leaf, dref, offset);
btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
struct btrfs_shared_data_ref *sref;
sref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
} else {
btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
}
btrfs_mark_buffer_dirty(trans, leaf);
}
static int lookup_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref **ref_ret,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner, u64 offset)
{
int ret;
ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 0);
if (ret != -ENOENT)
return ret;
btrfs_release_path(path);
*ref_ret = NULL;
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
ret = lookup_tree_block_ref(trans, path, bytenr, parent,
root_objectid);
} else {
ret = lookup_extent_data_ref(trans, path, bytenr, parent,
root_objectid, owner, offset);
}
return ret;
}
/*
* helper to update/remove inline back ref
*/
static noinline_for_stack int update_inline_extent_backref(
struct btrfs_trans_handle *trans,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_mod,
struct btrfs_delayed_extent_op *extent_op)
{
struct extent_buffer *leaf = path->nodes[0];
struct btrfs_fs_info *fs_info = leaf->fs_info;
struct btrfs_extent_item *ei;
struct btrfs_extent_data_ref *dref = NULL;
struct btrfs_shared_data_ref *sref = NULL;
unsigned long ptr;
unsigned long end;
u32 item_size;
int size;
int type;
u64 refs;
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, ei);
if (unlikely(refs_to_mod < 0 && refs + refs_to_mod <= 0)) {
struct btrfs_key key;
u32 extent_size;
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type == BTRFS_METADATA_ITEM_KEY)
extent_size = fs_info->nodesize;
else
extent_size = key.offset;
btrfs_print_leaf(leaf);
btrfs_err(fs_info,
"invalid refs_to_mod for extent %llu num_bytes %u, has %d expect >= -%llu",
key.objectid, extent_size, refs_to_mod, refs);
return -EUCLEAN;
}
refs += refs_to_mod;
btrfs_set_extent_refs(leaf, ei, refs);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
/*
* Function btrfs_get_extent_inline_ref_type() has already printed
* error messages.
*/
if (unlikely(type == BTRFS_REF_TYPE_INVALID))
return -EUCLEAN;
if (type == BTRFS_EXTENT_DATA_REF_KEY) {
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
refs = btrfs_extent_data_ref_count(leaf, dref);
} else if (type == BTRFS_SHARED_DATA_REF_KEY) {
sref = (struct btrfs_shared_data_ref *)(iref + 1);
refs = btrfs_shared_data_ref_count(leaf, sref);
} else {
refs = 1;
/*
* For tree blocks we can only drop one ref for it, and tree
* blocks should not have refs > 1.
*
* Furthermore if we're inserting a new inline backref, we
* won't reach this path either. That would be
* setup_inline_extent_backref().
*/
if (unlikely(refs_to_mod != -1)) {
struct btrfs_key key;
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
btrfs_print_leaf(leaf);
btrfs_err(fs_info,
"invalid refs_to_mod for tree block %llu, has %d expect -1",
key.objectid, refs_to_mod);
return -EUCLEAN;
}
}
if (unlikely(refs_to_mod < 0 && refs < -refs_to_mod)) {
struct btrfs_key key;
u32 extent_size;
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.type == BTRFS_METADATA_ITEM_KEY)
extent_size = fs_info->nodesize;
else
extent_size = key.offset;
btrfs_print_leaf(leaf);
btrfs_err(fs_info,
"invalid refs_to_mod for backref entry, iref %lu extent %llu num_bytes %u, has %d expect >= -%llu",
(unsigned long)iref, key.objectid, extent_size,
refs_to_mod, refs);
return -EUCLEAN;
}
refs += refs_to_mod;
if (refs > 0) {
if (type == BTRFS_EXTENT_DATA_REF_KEY)
btrfs_set_extent_data_ref_count(leaf, dref, refs);
else
btrfs_set_shared_data_ref_count(leaf, sref, refs);
} else {
size = btrfs_extent_inline_ref_size(type);
item_size = btrfs_item_size(leaf, path->slots[0]);
ptr = (unsigned long)iref;
end = (unsigned long)ei + item_size;
if (ptr + size < end)
memmove_extent_buffer(leaf, ptr, ptr + size,
end - ptr - size);
item_size -= size;
btrfs_truncate_item(trans, path, item_size, 1);
}
btrfs_mark_buffer_dirty(trans, leaf);
return 0;
}
static noinline_for_stack
int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_path *path,
u64 bytenr, u64 num_bytes, u64 parent,
u64 root_objectid, u64 owner,
u64 offset, int refs_to_add,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_extent_inline_ref *iref;
int ret;
ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
num_bytes, parent, root_objectid,
owner, offset, 1);
if (ret == 0) {
/*
* We're adding refs to a tree block we already own, this
* should not happen at all.
*/
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
btrfs_print_leaf(path->nodes[0]);
btrfs_crit(trans->fs_info,
"adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu slot %u",
bytenr, num_bytes, root_objectid, path->slots[0]);
return -EUCLEAN;
}
ret = update_inline_extent_backref(trans, path, iref,
refs_to_add, extent_op);
} else if (ret == -ENOENT) {
setup_inline_extent_backref(trans, path, iref, parent,
root_objectid, owner, offset,
refs_to_add, extent_op);
ret = 0;
}
return ret;
}
static int remove_extent_backref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct btrfs_extent_inline_ref *iref,
int refs_to_drop, int is_data)
{
int ret = 0;
BUG_ON(!is_data && refs_to_drop != 1);
if (iref)
ret = update_inline_extent_backref(trans, path, iref,
-refs_to_drop, NULL);
else if (is_data)
ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
else
ret = btrfs_del_item(trans, root, path);
return ret;
}
static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
u64 *discarded_bytes)
{
int j, ret = 0;
u64 bytes_left, end;
u64 aligned_start = ALIGN(start, 1 << SECTOR_SHIFT);
/* Adjust the range to be aligned to 512B sectors if necessary. */
if (start != aligned_start) {
len -= aligned_start - start;
len = round_down(len, 1 << SECTOR_SHIFT);
start = aligned_start;
}
*discarded_bytes = 0;
if (!len)
return 0;
end = start + len;
bytes_left = len;
/* Skip any superblocks on this device. */
for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
u64 sb_start = btrfs_sb_offset(j);
u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
u64 size = sb_start - start;
if (!in_range(sb_start, start, bytes_left) &&
!in_range(sb_end, start, bytes_left) &&
!in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
continue;
/*
* Superblock spans beginning of range. Adjust start and
* try again.
*/
if (sb_start <= start) {
start += sb_end - start;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
continue;
}
if (size) {
ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
size >> SECTOR_SHIFT,
GFP_NOFS);
if (!ret)
*discarded_bytes += size;
else if (ret != -EOPNOTSUPP)
return ret;
}
start = sb_end;
if (start > end) {
bytes_left = 0;
break;
}
bytes_left = end - start;
}
if (bytes_left) {
ret = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
bytes_left >> SECTOR_SHIFT,
GFP_NOFS);
if (!ret)
*discarded_bytes += bytes_left;
}
return ret;
}
static int do_discard_extent(struct btrfs_discard_stripe *stripe, u64 *bytes)
{
struct btrfs_device *dev = stripe->dev;
struct btrfs_fs_info *fs_info = dev->fs_info;
struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
u64 phys = stripe->physical;
u64 len = stripe->length;
u64 discarded = 0;
int ret = 0;
/* Zone reset on a zoned filesystem */
if (btrfs_can_zone_reset(dev, phys, len)) {
u64 src_disc;
ret = btrfs_reset_device_zone(dev, phys, len, &discarded);
if (ret)
goto out;
if (!btrfs_dev_replace_is_ongoing(dev_replace) ||
dev != dev_replace->srcdev)
goto out;
src_disc = discarded;
/* Send to replace target as well */
ret = btrfs_reset_device_zone(dev_replace->tgtdev, phys, len,
&discarded);
discarded += src_disc;
} else if (bdev_max_discard_sectors(stripe->dev->bdev)) {
ret = btrfs_issue_discard(dev->bdev, phys, len, &discarded);
} else {
ret = 0;
*bytes = 0;
}
out:
*bytes = discarded;
return ret;
}
int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
u64 num_bytes, u64 *actual_bytes)
{
int ret = 0;
u64 discarded_bytes = 0;
u64 end = bytenr + num_bytes;
u64 cur = bytenr;
/*
* Avoid races with device replace and make sure the devices in the
* stripes don't go away while we are discarding.
*/
btrfs_bio_counter_inc_blocked(fs_info);
while (cur < end) {
struct btrfs_discard_stripe *stripes;
unsigned int num_stripes;
int i;
num_bytes = end - cur;
stripes = btrfs_map_discard(fs_info, cur, &num_bytes, &num_stripes);
if (IS_ERR(stripes)) {
ret = PTR_ERR(stripes);
if (ret == -EOPNOTSUPP)
ret = 0;
break;
}
for (i = 0; i < num_stripes; i++) {
struct btrfs_discard_stripe *stripe = stripes + i;
u64 bytes;
if (!stripe->dev->bdev) {
ASSERT(btrfs_test_opt(fs_info, DEGRADED));
continue;
}
if (!test_bit(BTRFS_DEV_STATE_WRITEABLE,
&stripe->dev->dev_state))
continue;
ret = do_discard_extent(stripe, &bytes);
if (ret) {
/*
* Keep going if discard is not supported by the
* device.
*/
if (ret != -EOPNOTSUPP)
break;
ret = 0;
} else {
discarded_bytes += bytes;
}
}
kfree(stripes);
if (ret)
break;
cur += num_bytes;
}
btrfs_bio_counter_dec(fs_info);
if (actual_bytes)
*actual_bytes = discarded_bytes;
return ret;
}
/* Can return -ENOMEM */
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_ref *generic_ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
generic_ref->action);
BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
generic_ref->ref_root == BTRFS_TREE_LOG_OBJECTID);
if (generic_ref->type == BTRFS_REF_METADATA)
ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL);
else
ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0);
btrfs_ref_tree_mod(fs_info, generic_ref);
return ret;
}
/*
* Insert backreference for a given extent.
*
* The counterpart is in __btrfs_free_extent(), with examples and more details
* how it works.
*
* @trans: Handle of transaction
*
* @node: The delayed ref node used to get the bytenr/length for
* extent whose references are incremented.
*
* @extent_op Pointer to a structure, holding information necessary when
* updating a tree block's flags
*
*/
static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_path *path;
struct extent_buffer *leaf;
struct btrfs_extent_item *item;
struct btrfs_key key;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
u64 owner = btrfs_delayed_ref_owner(node);
u64 offset = btrfs_delayed_ref_offset(node);
u64 refs;
int refs_to_add = node->ref_mod;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/* this will setup the path even if it fails to insert the back ref */
ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
node->parent, node->ref_root, owner,
offset, refs_to_add, extent_op);
if ((ret < 0 && ret != -EAGAIN) || !ret)
goto out;
/*
* Ok we had -EAGAIN which means we didn't have space to insert and
* inline extent ref, so just update the reference count and add a
* normal backref.
*/
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
refs = btrfs_extent_refs(leaf, item);
btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, item);
btrfs_mark_buffer_dirty(trans, leaf);
btrfs_release_path(path);
/* now insert the actual backref */
if (owner < BTRFS_FIRST_FREE_OBJECTID)
ret = insert_tree_block_ref(trans, path, node, bytenr);
else
ret = insert_extent_data_ref(trans, path, node, bytenr);
if (ret)
btrfs_abort_transaction(trans, ret);
out:
btrfs_free_path(path);
return ret;
}
static void free_head_ref_squota_rsv(struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_head *href)
{
u64 root = href->owning_root;
/*
* Don't check must_insert_reserved, as this is called from contexts
* where it has already been unset.
*/
if (btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_SIMPLE ||
!href->is_data || !is_fstree(root))
return;
btrfs_qgroup_free_refroot(fs_info, root, href->reserved_bytes,
BTRFS_QGROUP_RSV_DATA);
}
static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
bool insert_reserved)
{
int ret = 0;
u64 parent = 0;
u64 flags = 0;
trace_run_delayed_data_ref(trans->fs_info, node);
if (node->type == BTRFS_SHARED_DATA_REF_KEY)
parent = node->parent;
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
struct btrfs_key key;
struct btrfs_squota_delta delta = {
.root = href->owning_root,
.num_bytes = node->num_bytes,
.is_data = true,
.is_inc = true,
.generation = trans->transid,
};
u64 owner = btrfs_delayed_ref_owner(node);
u64 offset = btrfs_delayed_ref_offset(node);
if (extent_op)
flags |= extent_op->flags_to_set;
key.objectid = node->bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = node->num_bytes;
ret = alloc_reserved_file_extent(trans, parent, node->ref_root,
flags, owner, offset, &key,
node->ref_mod,
href->owning_root);
free_head_ref_squota_rsv(trans->fs_info, href);
if (!ret)
ret = btrfs_record_squota_delta(trans->fs_info, &delta);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, href, node, extent_op);
} else {
BUG();
}
return ret;
}
static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
struct extent_buffer *leaf,
struct btrfs_extent_item *ei)
{
u64 flags = btrfs_extent_flags(leaf, ei);
if (extent_op->update_flags) {
flags |= extent_op->flags_to_set;
btrfs_set_extent_flags(leaf, ei, flags);
}
if (extent_op->update_key) {
struct btrfs_tree_block_info *bi;
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
bi = (struct btrfs_tree_block_info *)(ei + 1);
btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
}
}
static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_extent_item *ei;
struct extent_buffer *leaf;
u32 item_size;
int ret;
int metadata = 1;
if (TRANS_ABORTED(trans))
return 0;
if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
metadata = 0;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
key.objectid = head->bytenr;
if (metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = head->level;
} else {
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = head->num_bytes;
}
root = btrfs_extent_root(fs_info, key.objectid);
again:
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret < 0) {
goto out;
} else if (ret > 0) {
if (metadata) {
if (path->slots[0] > 0) {
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == head->bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == head->num_bytes)
ret = 0;
}
if (ret > 0) {
btrfs_release_path(path);
metadata = 0;
key.objectid = head->bytenr;
key.offset = head->num_bytes;
key.type = BTRFS_EXTENT_ITEM_KEY;
goto again;
}
} else {
ret = -EUCLEAN;
btrfs_err(fs_info,
"missing extent item for extent %llu num_bytes %llu level %d",
head->bytenr, head->num_bytes, head->level);
goto out;
}
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, path->slots[0]);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EUCLEAN;
btrfs_err(fs_info,
"unexpected extent item size, has %u expect >= %zu",
item_size, sizeof(*ei));
btrfs_abort_transaction(trans, ret);
goto out;
}
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
__run_delayed_extent_op(extent_op, leaf, ei);
btrfs_mark_buffer_dirty(trans, leaf);
out:
btrfs_free_path(path);
return ret;
}
static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
bool insert_reserved)
{
int ret = 0;
struct btrfs_fs_info *fs_info = trans->fs_info;
u64 parent = 0;
u64 ref_root = 0;
trace_run_delayed_tree_ref(trans->fs_info, node);
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
parent = node->parent;
ref_root = node->ref_root;
if (unlikely(node->ref_mod != 1)) {
btrfs_err(trans->fs_info,
"btree block %llu has %d references rather than 1: action %d ref_root %llu parent %llu",
node->bytenr, node->ref_mod, node->action, ref_root,
parent);
return -EUCLEAN;
}
if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
struct btrfs_squota_delta delta = {
.root = href->owning_root,
.num_bytes = fs_info->nodesize,
.is_data = false,
.is_inc = true,
.generation = trans->transid,
};
ret = alloc_reserved_tree_block(trans, node, extent_op);
if (!ret)
btrfs_record_squota_delta(fs_info, &delta);
} else if (node->action == BTRFS_ADD_DELAYED_REF) {
ret = __btrfs_inc_extent_ref(trans, node, extent_op);
} else if (node->action == BTRFS_DROP_DELAYED_REF) {
ret = __btrfs_free_extent(trans, href, node, extent_op);
} else {
BUG();
}
return ret;
}
/* helper function to actually process a single delayed ref entry */
static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op,
bool insert_reserved)
{
int ret = 0;
if (TRANS_ABORTED(trans)) {
if (insert_reserved) {
btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
free_head_ref_squota_rsv(trans->fs_info, href);
}
return 0;
}
if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
node->type == BTRFS_SHARED_BLOCK_REF_KEY)
ret = run_delayed_tree_ref(trans, href, node, extent_op,
insert_reserved);
else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
node->type == BTRFS_SHARED_DATA_REF_KEY)
ret = run_delayed_data_ref(trans, href, node, extent_op,
insert_reserved);
else if (node->type == BTRFS_EXTENT_OWNER_REF_KEY)
ret = 0;
else
BUG();
if (ret && insert_reserved)
btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
if (ret < 0)
btrfs_err(trans->fs_info,
"failed to run delayed ref for logical %llu num_bytes %llu type %u action %u ref_mod %d: %d",
node->bytenr, node->num_bytes, node->type,
node->action, node->ref_mod, ret);
return ret;
}
static inline struct btrfs_delayed_ref_node *
select_delayed_ref(struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_ref_node *ref;
if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
return NULL;
/*
* Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
* This is to prevent a ref count from going down to zero, which deletes
* the extent item from the extent tree, when there still are references
* to add, which would fail because they would not find the extent item.
*/
if (!list_empty(&head->ref_add_list))
return list_first_entry(&head->ref_add_list,
struct btrfs_delayed_ref_node, add_list);
ref = rb_entry(rb_first_cached(&head->ref_tree),
struct btrfs_delayed_ref_node, ref_node);
ASSERT(list_empty(&ref->add_list));
return ref;
}
static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
spin_lock(&delayed_refs->lock);
head->processing = false;
delayed_refs->num_heads_ready++;
spin_unlock(&delayed_refs->lock);
btrfs_delayed_ref_unlock(head);
}
static struct btrfs_delayed_extent_op *cleanup_extent_op(
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
if (!extent_op)
return NULL;
if (head->must_insert_reserved) {
head->extent_op = NULL;
btrfs_free_delayed_extent_op(extent_op);
return NULL;
}
return extent_op;
}
static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = cleanup_extent_op(head);
if (!extent_op)
return 0;
head->extent_op = NULL;
spin_unlock(&head->lock);
ret = run_delayed_extent_op(trans, head, extent_op);
btrfs_free_delayed_extent_op(extent_op);
return ret ? ret : 1;
}
u64 btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
u64 ret = 0;
/*
* We had csum deletions accounted for in our delayed refs rsv, we need
* to drop the csum leaves for this update from our delayed_refs_rsv.
*/
if (head->total_ref_mod < 0 && head->is_data) {
int nr_csums;
spin_lock(&delayed_refs->lock);
delayed_refs->pending_csums -= head->num_bytes;
spin_unlock(&delayed_refs->lock);
nr_csums = btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes);
btrfs_delayed_refs_rsv_release(fs_info, 0, nr_csums);
ret = btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums);
}
/* must_insert_reserved can be set only if we didn't run the head ref. */
if (head->must_insert_reserved)
free_head_ref_squota_rsv(fs_info, head);
return ret;
}
static int cleanup_ref_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head,
u64 *bytes_released)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
ret = run_and_cleanup_extent_op(trans, head);
if (ret < 0) {
unselect_delayed_ref_head(delayed_refs, head);
btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
return ret;
} else if (ret) {
return ret;
}
/*
* Need to drop our head ref lock and re-acquire the delayed ref lock
* and then re-check to make sure nobody got added.
*/
spin_unlock(&head->lock);
spin_lock(&delayed_refs->lock);
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
return 1;
}
btrfs_delete_ref_head(delayed_refs, head);
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
if (head->must_insert_reserved) {
btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1);
if (head->is_data) {
struct btrfs_root *csum_root;
csum_root = btrfs_csum_root(fs_info, head->bytenr);
ret = btrfs_del_csums(trans, csum_root, head->bytenr,
head->num_bytes);
}
}
*bytes_released += btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
trace_run_delayed_ref_head(fs_info, head, 0);
btrfs_delayed_ref_unlock(head);
btrfs_put_delayed_ref_head(head);
return ret;
}
static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
struct btrfs_trans_handle *trans)
{
struct btrfs_delayed_ref_root *delayed_refs =
&trans->transaction->delayed_refs;
struct btrfs_delayed_ref_head *head = NULL;
int ret;
spin_lock(&delayed_refs->lock);
head = btrfs_select_ref_head(delayed_refs);
if (!head) {
spin_unlock(&delayed_refs->lock);
return head;
}
/*
* Grab the lock that says we are going to process all the refs for
* this head
*/
ret = btrfs_delayed_ref_lock(delayed_refs, head);
spin_unlock(&delayed_refs->lock);
/*
* We may have dropped the spin lock to get the head mutex lock, and
* that might have given someone else time to free the head. If that's
* true, it has been removed from our list and we can move on.
*/
if (ret == -EAGAIN)
head = ERR_PTR(-EAGAIN);
return head;
}
static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *locked_ref,
u64 *bytes_released)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_delayed_ref_node *ref;
bool must_insert_reserved;
int ret;
delayed_refs = &trans->transaction->delayed_refs;
lockdep_assert_held(&locked_ref->mutex);
lockdep_assert_held(&locked_ref->lock);
while ((ref = select_delayed_ref(locked_ref))) {
if (ref->seq &&
btrfs_check_delayed_seq(fs_info, ref->seq)) {
spin_unlock(&locked_ref->lock);
unselect_delayed_ref_head(delayed_refs, locked_ref);
return -EAGAIN;
}
rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
/*
* When we play the delayed ref, also correct the ref_mod on
* head
*/
switch (ref->action) {
case BTRFS_ADD_DELAYED_REF:
case BTRFS_ADD_DELAYED_EXTENT:
locked_ref->ref_mod -= ref->ref_mod;
break;
case BTRFS_DROP_DELAYED_REF:
locked_ref->ref_mod += ref->ref_mod;
break;
default:
WARN_ON(1);
}
atomic_dec(&delayed_refs->num_entries);
/*
* Record the must_insert_reserved flag before we drop the
* spin lock.
*/
must_insert_reserved = locked_ref->must_insert_reserved;
/*
* Unsetting this on the head ref relinquishes ownership of
* the rsv_bytes, so it is critical that every possible code
* path from here forward frees all reserves including qgroup
* reserve.
*/
locked_ref->must_insert_reserved = false;
extent_op = locked_ref->extent_op;
locked_ref->extent_op = NULL;
spin_unlock(&locked_ref->lock);
ret = run_one_delayed_ref(trans, locked_ref, ref, extent_op,
must_insert_reserved);
btrfs_delayed_refs_rsv_release(fs_info, 1, 0);
*bytes_released += btrfs_calc_delayed_ref_bytes(fs_info, 1);
btrfs_free_delayed_extent_op(extent_op);
if (ret) {
unselect_delayed_ref_head(delayed_refs, locked_ref);
btrfs_put_delayed_ref(ref);
return ret;
}
btrfs_put_delayed_ref(ref);
cond_resched();
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);
}
return 0;
}
/*
* Returns 0 on success or if called with an already aborted transaction.
* Returns -ENOMEM or -EIO on failure and will abort the transaction.
*/
static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
u64 min_bytes)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *locked_ref = NULL;
int ret;
unsigned long count = 0;
unsigned long max_count = 0;
u64 bytes_processed = 0;
delayed_refs = &trans->transaction->delayed_refs;
if (min_bytes == 0) {
max_count = delayed_refs->num_heads_ready;
min_bytes = U64_MAX;
}
do {
if (!locked_ref) {
locked_ref = btrfs_obtain_ref_head(trans);
if (IS_ERR_OR_NULL(locked_ref)) {
if (PTR_ERR(locked_ref) == -EAGAIN) {
continue;
} else {
break;
}
}
count++;
}
/*
* We need to try and merge add/drops of the same ref since we
* can run into issues with relocate dropping the implicit ref
* and then it being added back again before the drop can
* finish. If we merged anything we need to re-loop so we can
* get a good ref.
* Or we can get node references of the same type that weren't
* merged when created due to bumps in the tree mod seq, and
* we need to merge them to prevent adding an inline extent
* backref before dropping it (triggering a BUG_ON at
* insert_inline_extent_backref()).
*/
spin_lock(&locked_ref->lock);
btrfs_merge_delayed_refs(fs_info, delayed_refs, locked_ref);
ret = btrfs_run_delayed_refs_for_head(trans, locked_ref, &bytes_processed);
if (ret < 0 && ret != -EAGAIN) {
/*
* Error, btrfs_run_delayed_refs_for_head already
* unlocked everything so just bail out
*/
return ret;
} else if (!ret) {
/*
* Success, perform the usual cleanup of a processed
* head
*/
ret = cleanup_ref_head(trans, locked_ref, &bytes_processed);
if (ret > 0 ) {
/* We dropped our lock, we need to loop. */
ret = 0;
continue;
} else if (ret) {
return ret;
}
}
/*
* Either success case or btrfs_run_delayed_refs_for_head
* returned -EAGAIN, meaning we need to select another head
*/
locked_ref = NULL;
cond_resched();
} while ((min_bytes != U64_MAX && bytes_processed < min_bytes) ||
(max_count > 0 && count < max_count) ||
locked_ref);
return 0;
}
#ifdef SCRAMBLE_DELAYED_REFS
/*
* Normally delayed refs get processed in ascending bytenr order. This
* correlates in most cases to the order added. To expose dependencies on this
* order, we start to process the tree in the middle instead of the beginning
*/
static u64 find_middle(struct rb_root *root)
{
struct rb_node *n = root->rb_node;
struct btrfs_delayed_ref_node *entry;
int alt = 1;
u64 middle;
u64 first = 0, last = 0;
n = rb_first(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
first = entry->bytenr;
}
n = rb_last(root);
if (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
last = entry->bytenr;
}
n = root->rb_node;
while (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
WARN_ON(!entry->in_tree);
middle = entry->bytenr;
if (alt)
n = n->rb_left;
else
n = n->rb_right;
alt = 1 - alt;
}
return middle;
}
#endif
/*
* Start processing the delayed reference count updates and extent insertions
* we have queued up so far.
*
* @trans: Transaction handle.
* @min_bytes: How many bytes of delayed references to process. After this
* many bytes we stop processing delayed references if there are
* any more. If 0 it means to run all existing delayed references,
* but not new ones added after running all existing ones.
* Use (u64)-1 (U64_MAX) to run all existing delayed references
* plus any new ones that are added.
*
* Returns 0 on success or if called with an aborted transaction
* Returns <0 on error and aborts the transaction
*/
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans, u64 min_bytes)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_delayed_ref_root *delayed_refs;
int ret;
/* We'll clean this up in btrfs_cleanup_transaction */
if (TRANS_ABORTED(trans))
return 0;
if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
return 0;
delayed_refs = &trans->transaction->delayed_refs;
again:
#ifdef SCRAMBLE_DELAYED_REFS
delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
#endif
ret = __btrfs_run_delayed_refs(trans, min_bytes);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
return ret;
}
if (min_bytes == U64_MAX) {
btrfs_create_pending_block_groups(trans);
spin_lock(&delayed_refs->lock);
if (RB_EMPTY_ROOT(&delayed_refs->href_root.rb_root)) {
spin_unlock(&delayed_refs->lock);
return 0;
}
spin_unlock(&delayed_refs->lock);
cond_resched();
goto again;
}
return 0;
}
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
struct extent_buffer *eb, u64 flags)
{
struct btrfs_delayed_extent_op *extent_op;
int ret;
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op)
return -ENOMEM;
extent_op->flags_to_set = flags;
extent_op->update_flags = true;
extent_op->update_key = false;
ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len,
btrfs_header_level(eb), extent_op);
if (ret)
btrfs_free_delayed_extent_op(extent_op);
return ret;
}
static noinline int check_delayed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_node *ref;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_transaction *cur_trans;
struct rb_node *node;
int ret = 0;
spin_lock(&root->fs_info->trans_lock);
cur_trans = root->fs_info->running_transaction;
if (cur_trans)
refcount_inc(&cur_trans->use_count);
spin_unlock(&root->fs_info->trans_lock);
if (!cur_trans)
return 0;
delayed_refs = &cur_trans->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head) {
spin_unlock(&delayed_refs->lock);
btrfs_put_transaction(cur_trans);
return 0;
}
if (!mutex_trylock(&head->mutex)) {
if (path->nowait) {
spin_unlock(&delayed_refs->lock);
btrfs_put_transaction(cur_trans);
return -EAGAIN;
}
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's released and let
* caller try again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
btrfs_put_transaction(cur_trans);
return -EAGAIN;
}
spin_unlock(&delayed_refs->lock);
spin_lock(&head->lock);
/*
* XXX: We should replace this with a proper search function in the
* future.
*/
for (node = rb_first_cached(&head->ref_tree); node;
node = rb_next(node)) {
u64 ref_owner;
u64 ref_offset;
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
/* If it's a shared ref we know a cross reference exists */
if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
ret = 1;
break;
}
ref_owner = btrfs_delayed_ref_owner(ref);
ref_offset = btrfs_delayed_ref_offset(ref);
/*
* If our ref doesn't match the one we're currently looking at
* then we have a cross reference.
*/
if (ref->ref_root != btrfs_root_id(root) ||
ref_owner != objectid || ref_offset != offset) {
ret = 1;
break;
}
}
spin_unlock(&head->lock);
mutex_unlock(&head->mutex);
btrfs_put_transaction(cur_trans);
return ret;
}
static noinline int check_committed_ref(struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset, u64 bytenr,
bool strict)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
struct extent_buffer *leaf;
struct btrfs_extent_data_ref *ref;
struct btrfs_extent_inline_ref *iref;
struct btrfs_extent_item *ei;
struct btrfs_key key;
u32 item_size;
u32 expected_size;
int type;
int ret;
key.objectid = bytenr;
key.offset = (u64)-1;
key.type = BTRFS_EXTENT_ITEM_KEY;
ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret == 0) {
/*
* Key with offset -1 found, there would have to exist an extent
* item with such offset, but this is out of the valid range.
*/
ret = -EUCLEAN;
goto out;
}
ret = -ENOENT;
if (path->slots[0] == 0)
goto out;
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
goto out;
ret = 1;
item_size = btrfs_item_size(leaf, path->slots[0]);
ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
expected_size = sizeof(*ei) + btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY);
/* No inline refs; we need to bail before checking for owner ref. */
if (item_size == sizeof(*ei))
goto out;
/* Check for an owner ref; skip over it to the real inline refs. */
iref = (struct btrfs_extent_inline_ref *)(ei + 1);
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
if (btrfs_fs_incompat(fs_info, SIMPLE_QUOTA) && type == BTRFS_EXTENT_OWNER_REF_KEY) {
expected_size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
iref = (struct btrfs_extent_inline_ref *)(iref + 1);
}
/* If extent item has more than 1 inline ref then it's shared */
if (item_size != expected_size)
goto out;
/*
* If extent created before last snapshot => it's shared unless the
* snapshot has been deleted. Use the heuristic if strict is false.
*/
if (!strict &&
(btrfs_extent_generation(leaf, ei) <=
btrfs_root_last_snapshot(&root->root_item)))
goto out;
/* If this extent has SHARED_DATA_REF then it's shared */
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
if (type != BTRFS_EXTENT_DATA_REF_KEY)
goto out;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
if (btrfs_extent_refs(leaf, ei) !=
btrfs_extent_data_ref_count(leaf, ref) ||
btrfs_extent_data_ref_root(leaf, ref) != btrfs_root_id(root) ||
btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
btrfs_extent_data_ref_offset(leaf, ref) != offset)
goto out;
ret = 0;
out:
return ret;
}
int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
u64 bytenr, bool strict, struct btrfs_path *path)
{
int ret;
do {
ret = check_committed_ref(root, path, objectid,
offset, bytenr, strict);
if (ret && ret != -ENOENT)
goto out;
ret = check_delayed_ref(root, path, objectid, offset, bytenr);
} while (ret == -EAGAIN);
out:
btrfs_release_path(path);
if (btrfs_is_data_reloc_root(root))
WARN_ON(ret > 0);
return ret;
}
static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
int full_backref, int inc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 parent;
u64 ref_root;
u32 nritems;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
int i;
int action;
int level;
int ret = 0;
if (btrfs_is_testing(fs_info))
return 0;
ref_root = btrfs_header_owner(buf);
nritems = btrfs_header_nritems(buf);
level = btrfs_header_level(buf);
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
return 0;
if (full_backref)
parent = buf->start;
else
parent = 0;
if (inc)
action = BTRFS_ADD_DELAYED_REF;
else
action = BTRFS_DROP_DELAYED_REF;
for (i = 0; i < nritems; i++) {
struct btrfs_ref ref = {
.action = action,
.parent = parent,
.ref_root = ref_root,
};
if (level == 0) {
btrfs_item_key_to_cpu(buf, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(buf, i,
struct btrfs_file_extent_item);
if (btrfs_file_extent_type(buf, fi) ==
BTRFS_FILE_EXTENT_INLINE)
continue;
ref.bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
if (ref.bytenr == 0)
continue;
ref.num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
ref.owning_root = ref_root;
key.offset -= btrfs_file_extent_offset(buf, fi);
btrfs_init_data_ref(&ref, key.objectid, key.offset,
btrfs_root_id(root), for_reloc);
if (inc)
ret = btrfs_inc_extent_ref(trans, &ref);
else
ret = btrfs_free_extent(trans, &ref);
if (ret)
goto fail;
} else {
/* We don't know the owning_root, leave as 0. */
ref.bytenr = btrfs_node_blockptr(buf, i);
ref.num_bytes = fs_info->nodesize;
btrfs_init_tree_ref(&ref, level - 1,
btrfs_root_id(root), for_reloc);
if (inc)
ret = btrfs_inc_extent_ref(trans, &ref);
else
ret = btrfs_free_extent(trans, &ref);
if (ret)
goto fail;
}
}
return 0;
fail:
return ret;
}
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
}
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct extent_buffer *buf, int full_backref)
{
return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
}
static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 flags;
u64 ret;
if (data)
flags = BTRFS_BLOCK_GROUP_DATA;
else if (root == fs_info->chunk_root)
flags = BTRFS_BLOCK_GROUP_SYSTEM;
else
flags = BTRFS_BLOCK_GROUP_METADATA;
ret = btrfs_get_alloc_profile(fs_info, flags);
return ret;
}
static u64 first_logical_byte(struct btrfs_fs_info *fs_info)
{
struct rb_node *leftmost;
u64 bytenr = 0;
read_lock(&fs_info->block_group_cache_lock);
/* Get the block group with the lowest logical start address. */
leftmost = rb_first_cached(&fs_info->block_group_cache_tree);
if (leftmost) {
struct btrfs_block_group *bg;
bg = rb_entry(leftmost, struct btrfs_block_group, cache_node);
bytenr = bg->start;
}
read_unlock(&fs_info->block_group_cache_lock);
return bytenr;
}
static int pin_down_extent(struct btrfs_trans_handle *trans,
struct btrfs_block_group *cache,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
spin_lock(&cache->space_info->lock);
spin_lock(&cache->lock);
cache->pinned += num_bytes;
btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
num_bytes);
if (reserved) {
cache->reserved -= num_bytes;
cache->space_info->bytes_reserved -= num_bytes;
}
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
set_extent_bit(&trans->transaction->pinned_extents, bytenr,
bytenr + num_bytes - 1, EXTENT_DIRTY, NULL);
return 0;
}
int btrfs_pin_extent(struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, int reserved)
{
struct btrfs_block_group *cache;
cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
BUG_ON(!cache); /* Logic error */
pin_down_extent(trans, cache, bytenr, num_bytes, reserved);
btrfs_put_block_group(cache);
return 0;
}
int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
const struct extent_buffer *eb)
{
struct btrfs_block_group *cache;
int ret;
cache = btrfs_lookup_block_group(trans->fs_info, eb->start);
if (!cache)
return -EINVAL;
/*
* Fully cache the free space first so that our pin removes the free space
* from the cache.
*/
ret = btrfs_cache_block_group(cache, true);
if (ret)
goto out;
pin_down_extent(trans, cache, eb->start, eb->len, 0);
/* remove us from the free space cache (if we're there at all) */
ret = btrfs_remove_free_space(cache, eb->start, eb->len);
out:
btrfs_put_block_group(cache);
return ret;
}
static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 num_bytes)
{
int ret;
struct btrfs_block_group *block_group;
block_group = btrfs_lookup_block_group(fs_info, start);
if (!block_group)
return -EINVAL;
ret = btrfs_cache_block_group(block_group, true);
if (ret)
goto out;
ret = btrfs_remove_free_space(block_group, start, num_bytes);
out:
btrfs_put_block_group(block_group);
return ret;
}
int btrfs_exclude_logged_extents(struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct btrfs_file_extent_item *item;
struct btrfs_key key;
int found_type;
int i;
int ret = 0;
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
return 0;
for (i = 0; i < btrfs_header_nritems(eb); i++) {
btrfs_item_key_to_cpu(eb, &key, i);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(eb, item);
if (found_type == BTRFS_FILE_EXTENT_INLINE)
continue;
if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
continue;
key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
if (ret)
break;
}
return ret;
}
static void
btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)
{
atomic_inc(&bg->reservations);
}
/*
* Returns the free cluster for the given space info and sets empty_cluster to
* what it should be based on the mount options.
*/
static struct btrfs_free_cluster *
fetch_cluster_info(struct btrfs_fs_info *fs_info,
struct btrfs_space_info *space_info, u64 *empty_cluster)
{
struct btrfs_free_cluster *ret = NULL;
*empty_cluster = 0;
if (btrfs_mixed_space_info(space_info))
return ret;
if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
ret = &fs_info->meta_alloc_cluster;
if (btrfs_test_opt(fs_info, SSD))
*empty_cluster = SZ_2M;
else
*empty_cluster = SZ_64K;
} else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
btrfs_test_opt(fs_info, SSD_SPREAD)) {
*empty_cluster = SZ_2M;
ret = &fs_info->data_alloc_cluster;
}
return ret;
}
static int unpin_extent_range(struct btrfs_fs_info *fs_info,
u64 start, u64 end,
const bool return_free_space)
{
struct btrfs_block_group *cache = NULL;
struct btrfs_space_info *space_info;
struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
struct btrfs_free_cluster *cluster = NULL;
u64 len;
u64 total_unpinned = 0;
u64 empty_cluster = 0;
bool readonly;
int ret = 0;
while (start <= end) {
readonly = false;
if (!cache ||
start >= cache->start + cache->length) {
if (cache)
btrfs_put_block_group(cache);
total_unpinned = 0;
cache = btrfs_lookup_block_group(fs_info, start);
if (cache == NULL) {
/* Logic error, something removed the block group. */
ret = -EUCLEAN;
goto out;
}
cluster = fetch_cluster_info(fs_info,
cache->space_info,
&empty_cluster);
empty_cluster <<= 1;
}
len = cache->start + cache->length - start;
len = min(len, end + 1 - start);
if (return_free_space)
btrfs_add_free_space(cache, start, len);
start += len;
total_unpinned += len;
space_info = cache->space_info;
/*
* If this space cluster has been marked as fragmented and we've
* unpinned enough in this block group to potentially allow a
* cluster to be created inside of it go ahead and clear the
* fragmented check.
*/
if (cluster && cluster->fragmented &&
total_unpinned > empty_cluster) {
spin_lock(&cluster->lock);
cluster->fragmented = 0;
spin_unlock(&cluster->lock);
}
spin_lock(&space_info->lock);
spin_lock(&cache->lock);
cache->pinned -= len;
btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
space_info->max_extent_size = 0;
if (cache->ro) {
space_info->bytes_readonly += len;
readonly = true;
} else if (btrfs_is_zoned(fs_info)) {
/* Need reset before reusing in a zoned block group */
btrfs_space_info_update_bytes_zone_unusable(fs_info, space_info,
len);
readonly = true;
}
spin_unlock(&cache->lock);
if (!readonly && return_free_space &&
global_rsv->space_info == space_info) {
spin_lock(&global_rsv->lock);
if (!global_rsv->full) {
u64 to_add = min(len, global_rsv->size -
global_rsv->reserved);
global_rsv->reserved += to_add;
btrfs_space_info_update_bytes_may_use(fs_info,
space_info, to_add);
if (global_rsv->reserved >= global_rsv->size)
global_rsv->full = 1;
len -= to_add;
}
spin_unlock(&global_rsv->lock);
}
/* Add to any tickets we may have */
if (!readonly && return_free_space && len)
btrfs_try_granting_tickets(fs_info, space_info);
spin_unlock(&space_info->lock);
}
if (cache)
btrfs_put_block_group(cache);
out:
return ret;
}
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group *block_group, *tmp;
struct list_head *deleted_bgs;
struct extent_io_tree *unpin;
u64 start;
u64 end;
int ret;
unpin = &trans->transaction->pinned_extents;
while (!TRANS_ABORTED(trans)) {
struct extent_state *cached_state = NULL;
mutex_lock(&fs_info->unused_bg_unpin_mutex);
if (!find_first_extent_bit(unpin, 0, &start, &end,
EXTENT_DIRTY, &cached_state)) {
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
break;
}
if (btrfs_test_opt(fs_info, DISCARD_SYNC))
ret = btrfs_discard_extent(fs_info, start,
end + 1 - start, NULL);
clear_extent_dirty(unpin, start, end, &cached_state);
ret = unpin_extent_range(fs_info, start, end, true);
BUG_ON(ret);
mutex_unlock(&fs_info->unused_bg_unpin_mutex);
free_extent_state(cached_state);
cond_resched();
}
if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
btrfs_discard_calc_delay(&fs_info->discard_ctl);
btrfs_discard_schedule_work(&fs_info->discard_ctl, true);
}
/*
* Transaction is finished. We don't need the lock anymore. We
* do need to clean up the block groups in case of a transaction
* abort.
*/
deleted_bgs = &trans->transaction->deleted_bgs;
list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
u64 trimmed = 0;
ret = -EROFS;
if (!TRANS_ABORTED(trans))
ret = btrfs_discard_extent(fs_info,
block_group->start,
block_group->length,
&trimmed);
list_del_init(&block_group->bg_list);
btrfs_unfreeze_block_group(block_group);
btrfs_put_block_group(block_group);
if (ret) {
const char *errstr = btrfs_decode_error(ret);
btrfs_warn(fs_info,
"discard failed while removing blockgroup: errno=%d %s",
ret, errstr);
}
}
return 0;
}
/*
* Parse an extent item's inline extents looking for a simple quotas owner ref.
*
* @fs_info: the btrfs_fs_info for this mount
* @leaf: a leaf in the extent tree containing the extent item
* @slot: the slot in the leaf where the extent item is found
*
* Returns the objectid of the root that originally allocated the extent item
* if the inline owner ref is expected and present, otherwise 0.
*
* If an extent item has an owner ref item, it will be the first inline ref
* item. Therefore the logic is to check whether there are any inline ref
* items, then check the type of the first one.
*/
u64 btrfs_get_extent_owner_root(struct btrfs_fs_info *fs_info,
struct extent_buffer *leaf, int slot)
{
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
struct btrfs_extent_owner_ref *oref;
unsigned long ptr;
unsigned long end;
int type;
if (!btrfs_fs_incompat(fs_info, SIMPLE_QUOTA))
return 0;
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
ptr = (unsigned long)(ei + 1);
end = (unsigned long)ei + btrfs_item_size(leaf, slot);
/* No inline ref items of any kind, can't check type. */
if (ptr == end)
return 0;
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
/* We found an owner ref, get the root out of it. */
if (type == BTRFS_EXTENT_OWNER_REF_KEY) {
oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
return btrfs_extent_owner_ref_root_id(leaf, oref);
}
/* We have inline refs, but not an owner ref. */
return 0;
}
static int do_free_extent_accounting(struct btrfs_trans_handle *trans,
u64 bytenr, struct btrfs_squota_delta *delta)
{
int ret;
u64 num_bytes = delta->num_bytes;
if (delta->is_data) {
struct btrfs_root *csum_root;
csum_root = btrfs_csum_root(trans->fs_info, bytenr);
ret = btrfs_del_csums(trans, csum_root, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_delete_raid_extent(trans, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
}
ret = btrfs_record_squota_delta(trans->fs_info, delta);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = add_to_free_space_tree(trans, bytenr, num_bytes);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_update_block_group(trans, bytenr, num_bytes, false);
if (ret)
btrfs_abort_transaction(trans, ret);
return ret;
}
#define abort_and_dump(trans, path, fmt, args...) \
({ \
btrfs_abort_transaction(trans, -EUCLEAN); \
btrfs_print_leaf(path->nodes[0]); \
btrfs_crit(trans->fs_info, fmt, ##args); \
})
/*
* Drop one or more refs of @node.
*
* 1. Locate the extent refs.
* It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item.
* Locate it, then reduce the refs number or remove the ref line completely.
*
* 2. Update the refs count in EXTENT/METADATA_ITEM
*
* Inline backref case:
*
* in extent tree we have:
*
* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
* refs 2 gen 6 flags DATA
* extent data backref root FS_TREE objectid 258 offset 0 count 1
* extent data backref root FS_TREE objectid 257 offset 0 count 1
*
* This function gets called with:
*
* node->bytenr = 13631488
* node->num_bytes = 1048576
* root_objectid = FS_TREE
* owner_objectid = 257
* owner_offset = 0
* refs_to_drop = 1
*
* Then we should get some like:
*
* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
* refs 1 gen 6 flags DATA
* extent data backref root FS_TREE objectid 258 offset 0 count 1
*
* Keyed backref case:
*
* in extent tree we have:
*
* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
* refs 754 gen 6 flags DATA
* [...]
* item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 28
* extent data backref root FS_TREE objectid 866 offset 0 count 1
*
* This function get called with:
*
* node->bytenr = 13631488
* node->num_bytes = 1048576
* root_objectid = FS_TREE
* owner_objectid = 866
* owner_offset = 0
* refs_to_drop = 1
*
* Then we should get some like:
*
* item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
* refs 753 gen 6 flags DATA
*
* And that (13631488 EXTENT_DATA_REF <HASH>) gets removed.
*/
static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_root *extent_root;
struct extent_buffer *leaf;
struct btrfs_extent_item *ei;
struct btrfs_extent_inline_ref *iref;
int ret;
int is_data;
int extent_slot = 0;
int found_extent = 0;
int num_to_del = 1;
int refs_to_drop = node->ref_mod;
u32 item_size;
u64 refs;
u64 bytenr = node->bytenr;
u64 num_bytes = node->num_bytes;
u64 owner_objectid = btrfs_delayed_ref_owner(node);
u64 owner_offset = btrfs_delayed_ref_offset(node);
bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
u64 delayed_ref_root = href->owning_root;
extent_root = btrfs_extent_root(info, bytenr);
ASSERT(extent_root);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
if (!is_data && refs_to_drop != 1) {
btrfs_crit(info,
"invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",
node->bytenr, refs_to_drop);
ret = -EINVAL;
btrfs_abort_transaction(trans, ret);
goto out;
}
if (is_data)
skinny_metadata = false;
ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
node->parent, node->ref_root, owner_objectid,
owner_offset);
if (ret == 0) {
/*
* Either the inline backref or the SHARED_DATA_REF/
* SHARED_BLOCK_REF is found
*
* Here is a quick path to locate EXTENT/METADATA_ITEM.
* It's possible the EXTENT/METADATA_ITEM is near current slot.
*/
extent_slot = path->slots[0];
while (extent_slot >= 0) {
btrfs_item_key_to_cpu(path->nodes[0], &key,
extent_slot);
if (key.objectid != bytenr)
break;
if (key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes) {
found_extent = 1;
break;
}
if (key.type == BTRFS_METADATA_ITEM_KEY &&
key.offset == owner_objectid) {
found_extent = 1;
break;
}
/* Quick path didn't find the EXTEMT/METADATA_ITEM */
if (path->slots[0] - extent_slot > 5)
break;
extent_slot--;
}
if (!found_extent) {
if (iref) {
abort_and_dump(trans, path,
"invalid iref slot %u, no EXTENT/METADATA_ITEM found but has inline extent ref",
path->slots[0]);
ret = -EUCLEAN;
goto out;
}
/* Must be SHARED_* item, remove the backref first */
ret = remove_extent_backref(trans, extent_root, path,
NULL, refs_to_drop, is_data);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
/* Slow path to locate EXTENT/METADATA_ITEM */
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
if (!is_data && skinny_metadata) {
key.type = BTRFS_METADATA_ITEM_KEY;
key.offset = owner_objectid;
}
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
if (ret > 0 && skinny_metadata && path->slots[0]) {
/*
* Couldn't find our skinny metadata item,
* see if we have ye olde extent item.
*/
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &key,
path->slots[0]);
if (key.objectid == bytenr &&
key.type == BTRFS_EXTENT_ITEM_KEY &&
key.offset == num_bytes)
ret = 0;
}
if (ret > 0 && skinny_metadata) {
skinny_metadata = false;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = num_bytes;
btrfs_release_path(path);
ret = btrfs_search_slot(trans, extent_root,
&key, path, -1, 1);
}
if (ret) {
if (ret > 0)
btrfs_print_leaf(path->nodes[0]);
btrfs_err(info,
"umm, got %d back from search, was looking for %llu, slot %d",
ret, bytenr, path->slots[0]);
}
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out;
}
extent_slot = path->slots[0];
}
} else if (WARN_ON(ret == -ENOENT)) {
abort_and_dump(trans, path,
"unable to find ref byte nr %llu parent %llu root %llu owner %llu offset %llu slot %d",
bytenr, node->parent, node->ref_root, owner_objectid,
owner_offset, path->slots[0]);
goto out;
} else {
btrfs_abort_transaction(trans, ret);
goto out;
}
leaf = path->nodes[0];
item_size = btrfs_item_size(leaf, extent_slot);
if (unlikely(item_size < sizeof(*ei))) {
ret = -EUCLEAN;
btrfs_err(trans->fs_info,
"unexpected extent item size, has %u expect >= %zu",
item_size, sizeof(*ei));
btrfs_abort_transaction(trans, ret);
goto out;
}
ei = btrfs_item_ptr(leaf, extent_slot,
struct btrfs_extent_item);
if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
key.type == BTRFS_EXTENT_ITEM_KEY) {
struct btrfs_tree_block_info *bi;
if (item_size < sizeof(*ei) + sizeof(*bi)) {
abort_and_dump(trans, path,
"invalid extent item size for key (%llu, %u, %llu) slot %u owner %llu, has %u expect >= %zu",
key.objectid, key.type, key.offset,
path->slots[0], owner_objectid, item_size,
sizeof(*ei) + sizeof(*bi));
ret = -EUCLEAN;
goto out;
}
bi = (struct btrfs_tree_block_info *)(ei + 1);
WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
}
refs = btrfs_extent_refs(leaf, ei);
if (refs < refs_to_drop) {
abort_and_dump(trans, path,
"trying to drop %d refs but we only have %llu for bytenr %llu slot %u",
refs_to_drop, refs, bytenr, path->slots[0]);
ret = -EUCLEAN;
goto out;
}
refs -= refs_to_drop;
if (refs > 0) {
if (extent_op)
__run_delayed_extent_op(extent_op, leaf, ei);
/*
* In the case of inline back ref, reference count will
* be updated by remove_extent_backref
*/
if (iref) {
if (!found_extent) {
abort_and_dump(trans, path,
"invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found, slot %u",
path->slots[0]);
ret = -EUCLEAN;
goto out;
}
} else {
btrfs_set_extent_refs(leaf, ei, refs);
btrfs_mark_buffer_dirty(trans, leaf);
}
if (found_extent) {
ret = remove_extent_backref(trans, extent_root, path,
iref, refs_to_drop, is_data);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
}
} else {
struct btrfs_squota_delta delta = {
.root = delayed_ref_root,
.num_bytes = num_bytes,
.is_data = is_data,
.is_inc = false,
.generation = btrfs_extent_generation(leaf, ei),
};
/* In this branch refs == 1 */
if (found_extent) {
if (is_data && refs_to_drop !=
extent_data_ref_count(path, iref)) {
abort_and_dump(trans, path,
"invalid refs_to_drop, current refs %u refs_to_drop %u slot %u",
extent_data_ref_count(path, iref),
refs_to_drop, path->slots[0]);
ret = -EUCLEAN;
goto out;
}
if (iref) {
if (path->slots[0] != extent_slot) {
abort_and_dump(trans, path,
"invalid iref, extent item key (%llu %u %llu) slot %u doesn't have wanted iref",
key.objectid, key.type,
key.offset, path->slots[0]);
ret = -EUCLEAN;
goto out;
}
} else {
/*
* No inline ref, we must be at SHARED_* item,
* And it's single ref, it must be:
* | extent_slot ||extent_slot + 1|
* [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ]
*/
if (path->slots[0] != extent_slot + 1) {
abort_and_dump(trans, path,
"invalid SHARED_* item slot %u, previous item is not EXTENT/METADATA_ITEM",
path->slots[0]);
ret = -EUCLEAN;
goto out;
}
path->slots[0] = extent_slot;
num_to_del = 2;
}
}
/*
* We can't infer the data owner from the delayed ref, so we need
* to try to get it from the owning ref item.
*
* If it is not present, then that extent was not written under
* simple quotas mode, so we don't need to account for its deletion.
*/
if (is_data)
delta.root = btrfs_get_extent_owner_root(trans->fs_info,
leaf, extent_slot);
ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
num_to_del);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out;
}
btrfs_release_path(path);
ret = do_free_extent_accounting(trans, bytenr, &delta);
}
btrfs_release_path(path);
out:
btrfs_free_path(path);
return ret;
}
/*
* when we free an block, it is possible (and likely) that we free the last
* delayed ref for that extent as well. This searches the delayed ref tree for
* a given extent, and if there are no other delayed refs to be processed, it
* removes it from the tree.
*/
static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
u64 bytenr)
{
struct btrfs_delayed_ref_head *head;
struct btrfs_delayed_ref_root *delayed_refs;
int ret = 0;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head)
goto out_delayed_unlock;
spin_lock(&head->lock);
if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
goto out;
if (cleanup_extent_op(head) != NULL)
goto out;
/*
* waiting for the lock here would deadlock. If someone else has it
* locked they are already in the process of dropping it anyway
*/
if (!mutex_trylock(&head->mutex))
goto out;
btrfs_delete_ref_head(delayed_refs, head);
head->processing = false;
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
BUG_ON(head->extent_op);
if (head->must_insert_reserved)
ret = 1;
btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
return ret;
out:
spin_unlock(&head->lock);
out_delayed_unlock:
spin_unlock(&delayed_refs->lock);
return 0;
}
int btrfs_free_tree_block(struct btrfs_trans_handle *trans,
u64 root_id,
struct extent_buffer *buf,
u64 parent, int last_ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group *bg;
int ret;
if (root_id != BTRFS_TREE_LOG_OBJECTID) {
struct btrfs_ref generic_ref = {
.action = BTRFS_DROP_DELAYED_REF,
.bytenr = buf->start,
.num_bytes = buf->len,
.parent = parent,
.owning_root = btrfs_header_owner(buf),
.ref_root = root_id,
};
/*
* Assert that the extent buffer is not cleared due to
* EXTENT_BUFFER_ZONED_ZEROOUT. Please refer
* btrfs_clear_buffer_dirty() and btree_csum_one_bio() for
* detail.
*/
ASSERT(btrfs_header_bytenr(buf) != 0);
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf), 0, false);
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);
if (ret < 0)
return ret;
}
if (!last_ref)
return 0;
if (btrfs_header_generation(buf) != trans->transid)
goto out;
if (root_id != BTRFS_TREE_LOG_OBJECTID) {
ret = check_ref_cleanup(trans, buf->start);
if (!ret)
goto out;
}
bg = btrfs_lookup_block_group(fs_info, buf->start);
if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
pin_down_extent(trans, bg, buf->start, buf->len, 1);
btrfs_put_block_group(bg);
goto out;
}
/*
* If there are tree mod log users we may have recorded mod log
* operations for this node. If we re-allocate this node we
* could replay operations on this node that happened when it
* existed in a completely different root. For example if it
* was part of root A, then was reallocated to root B, and we
* are doing a btrfs_old_search_slot(root b), we could replay
* operations that happened when the block was part of root A,
* giving us an inconsistent view of the btree.
*
* We are safe from races here because at this point no other
* node or root points to this extent buffer, so if after this
* check a new tree mod log user joins we will not have an
* existing log of operations on this node that we have to
* contend with.
*/
if (test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)
|| btrfs_is_zoned(fs_info)) {
pin_down_extent(trans, bg, buf->start, buf->len, 1);
btrfs_put_block_group(bg);
goto out;
}
WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
btrfs_add_free_space(bg, buf->start, buf->len);
btrfs_free_reserved_bytes(bg, buf->len, 0);
btrfs_put_block_group(bg);
trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
out:
/*
* Deleting the buffer, clear the corrupt flag since it doesn't
* matter anymore.
*/
clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
return 0;
}
/* Can return -ENOMEM */
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
if (btrfs_is_testing(fs_info))
return 0;
/*
* tree log blocks never actually go into the extent allocation
* tree, just update pinning info and exit early.
*/
if (ref->ref_root == BTRFS_TREE_LOG_OBJECTID) {
btrfs_pin_extent(trans, ref->bytenr, ref->num_bytes, 1);
ret = 0;
} else if (ref->type == BTRFS_REF_METADATA) {
ret = btrfs_add_delayed_tree_ref(trans, ref, NULL);
} else {
ret = btrfs_add_delayed_data_ref(trans, ref, 0);
}
if (ref->ref_root != BTRFS_TREE_LOG_OBJECTID)
btrfs_ref_tree_mod(fs_info, ref);
return ret;
}
enum btrfs_loop_type {
/*
* Start caching block groups but do not wait for progress or for them
* to be done.
*/
LOOP_CACHING_NOWAIT,
/*
* Wait for the block group free_space >= the space we're waiting for if
* the block group isn't cached.
*/
LOOP_CACHING_WAIT,
/*
* Allow allocations to happen from block groups that do not yet have a
* size classification.
*/
LOOP_UNSET_SIZE_CLASS,
/*
* Allocate a chunk and then retry the allocation.
*/
LOOP_ALLOC_CHUNK,
/*
* Ignore the size class restrictions for this allocation.
*/
LOOP_WRONG_SIZE_CLASS,
/*
* Ignore the empty size, only try to allocate the number of bytes
* needed for this allocation.
*/
LOOP_NO_EMPTY_SIZE,
};
static inline void
btrfs_lock_block_group(struct btrfs_block_group *cache,
int delalloc)
{
if (delalloc)
down_read(&cache->data_rwsem);
}
static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,
int delalloc)
{
btrfs_get_block_group(cache);
if (delalloc)
down_read(&cache->data_rwsem);
}
static struct btrfs_block_group *btrfs_lock_cluster(
struct btrfs_block_group *block_group,
struct btrfs_free_cluster *cluster,
int delalloc)
__acquires(&cluster->refill_lock)
{
struct btrfs_block_group *used_bg = NULL;
spin_lock(&cluster->refill_lock);
while (1) {
used_bg = cluster->block_group;
if (!used_bg)
return NULL;
if (used_bg == block_group)
return used_bg;
btrfs_get_block_group(used_bg);
if (!delalloc)
return used_bg;
if (down_read_trylock(&used_bg->data_rwsem))
return used_bg;
spin_unlock(&cluster->refill_lock);
/* We should only have one-level nested. */
down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
spin_lock(&cluster->refill_lock);
if (used_bg == cluster->block_group)
return used_bg;
up_read(&used_bg->data_rwsem);
btrfs_put_block_group(used_bg);
}
}
static inline void
btrfs_release_block_group(struct btrfs_block_group *cache,
int delalloc)
{
if (delalloc)
up_read(&cache->data_rwsem);
btrfs_put_block_group(cache);
}
/*
* Helper function for find_free_extent().
*
* Return -ENOENT to inform caller that we need fallback to unclustered mode.
* Return >0 to inform caller that we find nothing
* Return 0 means we have found a location and set ffe_ctl->found_offset.
*/
static int find_free_extent_clustered(struct btrfs_block_group *bg,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group **cluster_bg_ret)
{
struct btrfs_block_group *cluster_bg;
struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
u64 aligned_cluster;
u64 offset;
int ret;
cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
if (!cluster_bg)
goto refill_cluster;
if (cluster_bg != bg && (cluster_bg->ro ||
!block_group_bits(cluster_bg, ffe_ctl->flags)))
goto release_cluster;
offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
ffe_ctl->num_bytes, cluster_bg->start,
&ffe_ctl->max_extent_size);
if (offset) {
/* We have a block, we're done */
spin_unlock(&last_ptr->refill_lock);
trace_btrfs_reserve_extent_cluster(cluster_bg, ffe_ctl);
*cluster_bg_ret = cluster_bg;
ffe_ctl->found_offset = offset;
return 0;
}
WARN_ON(last_ptr->block_group != cluster_bg);
release_cluster:
/*
* If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
* lets just skip it and let the allocator find whatever block it can
* find. If we reach this point, we will have tried the cluster
* allocator plenty of times and not have found anything, so we are
* likely way too fragmented for the clustering stuff to find anything.
*
* However, if the cluster is taken from the current block group,
* release the cluster first, so that we stand a better chance of
* succeeding in the unclustered allocation.
*/
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
spin_unlock(&last_ptr->refill_lock);
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
return -ENOENT;
}
/* This cluster didn't work out, free it and start over */
btrfs_return_cluster_to_free_space(NULL, last_ptr);
if (cluster_bg != bg)
btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
refill_cluster:
if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
spin_unlock(&last_ptr->refill_lock);
return -ENOENT;
}
aligned_cluster = max_t(u64,
ffe_ctl->empty_cluster + ffe_ctl->empty_size,
bg->full_stripe_len);
ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
ffe_ctl->num_bytes, aligned_cluster);
if (ret == 0) {
/* Now pull our allocation out of this cluster */
offset = btrfs_alloc_from_cluster(bg, last_ptr,
ffe_ctl->num_bytes, ffe_ctl->search_start,
&ffe_ctl->max_extent_size);
if (offset) {
/* We found one, proceed */
spin_unlock(&last_ptr->refill_lock);
ffe_ctl->found_offset = offset;
trace_btrfs_reserve_extent_cluster(bg, ffe_ctl);
return 0;
}
}
/*
* At this point we either didn't find a cluster or we weren't able to
* allocate a block from our cluster. Free the cluster we've been
* trying to use, and go to the next block group.
*/
btrfs_return_cluster_to_free_space(NULL, last_ptr);
spin_unlock(&last_ptr->refill_lock);
return 1;
}
/*
* Return >0 to inform caller that we find nothing
* Return 0 when we found an free extent and set ffe_ctrl->found_offset
*/
static int find_free_extent_unclustered(struct btrfs_block_group *bg,
struct find_free_extent_ctl *ffe_ctl)
{
struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
u64 offset;
/*
* We are doing an unclustered allocation, set the fragmented flag so
* we don't bother trying to setup a cluster again until we get more
* space.
*/
if (unlikely(last_ptr)) {
spin_lock(&last_ptr->lock);
last_ptr->fragmented = 1;
spin_unlock(&last_ptr->lock);
}
if (ffe_ctl->cached) {
struct btrfs_free_space_ctl *free_space_ctl;
free_space_ctl = bg->free_space_ctl;
spin_lock(&free_space_ctl->tree_lock);
if (free_space_ctl->free_space <
ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
ffe_ctl->empty_size) {
ffe_ctl->total_free_space = max_t(u64,
ffe_ctl->total_free_space,
free_space_ctl->free_space);
spin_unlock(&free_space_ctl->tree_lock);
return 1;
}
spin_unlock(&free_space_ctl->tree_lock);
}
offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
ffe_ctl->num_bytes, ffe_ctl->empty_size,
&ffe_ctl->max_extent_size);
if (!offset)
return 1;
ffe_ctl->found_offset = offset;
return 0;
}
static int do_allocation_clustered(struct btrfs_block_group *block_group,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group **bg_ret)
{
int ret;
/* We want to try and use the cluster allocator, so lets look there */
if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {
ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret);
if (ret >= 0)
return ret;
/* ret == -ENOENT case falls through */
}
return find_free_extent_unclustered(block_group, ffe_ctl);
}
/*
* Tree-log block group locking
* ============================
*
* fs_info::treelog_bg_lock protects the fs_info::treelog_bg which
* indicates the starting address of a block group, which is reserved only
* for tree-log metadata.
*
* Lock nesting
* ============
*
* space_info::lock
* block_group::lock
* fs_info::treelog_bg_lock
*/
/*
* Simple allocator for sequential-only block group. It only allows sequential
* allocation. No need to play with trees. This function also reserves the
* bytes as in btrfs_add_reserved_bytes.
*/
static int do_allocation_zoned(struct btrfs_block_group *block_group,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group **bg_ret)
{
struct btrfs_fs_info *fs_info = block_group->fs_info;
struct btrfs_space_info *space_info = block_group->space_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
u64 start = block_group->start;
u64 num_bytes = ffe_ctl->num_bytes;
u64 avail;
u64 bytenr = block_group->start;
u64 log_bytenr;
u64 data_reloc_bytenr;
int ret = 0;
bool skip = false;
ASSERT(btrfs_is_zoned(block_group->fs_info));
/*
* Do not allow non-tree-log blocks in the dedicated tree-log block
* group, and vice versa.
*/
spin_lock(&fs_info->treelog_bg_lock);
log_bytenr = fs_info->treelog_bg;
if (log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||
(!ffe_ctl->for_treelog && bytenr == log_bytenr)))
skip = true;
spin_unlock(&fs_info->treelog_bg_lock);
if (skip)
return 1;
/*
* Do not allow non-relocation blocks in the dedicated relocation block
* group, and vice versa.
*/
spin_lock(&fs_info->relocation_bg_lock);
data_reloc_bytenr = fs_info->data_reloc_bg;
if (data_reloc_bytenr &&
((ffe_ctl->for_data_reloc && bytenr != data_reloc_bytenr) ||
(!ffe_ctl->for_data_reloc && bytenr == data_reloc_bytenr)))
skip = true;
spin_unlock(&fs_info->relocation_bg_lock);
if (skip)
return 1;
/* Check RO and no space case before trying to activate it */
spin_lock(&block_group->lock);
if (block_group->ro || btrfs_zoned_bg_is_full(block_group)) {
ret = 1;
/*
* May need to clear fs_info->{treelog,data_reloc}_bg.
* Return the error after taking the locks.
*/
}
spin_unlock(&block_group->lock);
/* Metadata block group is activated at write time. */
if (!ret && (block_group->flags & BTRFS_BLOCK_GROUP_DATA) &&
!btrfs_zone_activate(block_group)) {
ret = 1;
/*
* May need to clear fs_info->{treelog,data_reloc}_bg.
* Return the error after taking the locks.
*/
}
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
spin_lock(&fs_info->treelog_bg_lock);
spin_lock(&fs_info->relocation_bg_lock);
if (ret)
goto out;
ASSERT(!ffe_ctl->for_treelog ||
block_group->start == fs_info->treelog_bg ||
fs_info->treelog_bg == 0);
ASSERT(!ffe_ctl->for_data_reloc ||
block_group->start == fs_info->data_reloc_bg ||
fs_info->data_reloc_bg == 0);
if (block_group->ro ||
(!ffe_ctl->for_data_reloc &&
test_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags))) {
ret = 1;
goto out;
}
/*
* Do not allow currently using block group to be tree-log dedicated
* block group.
*/
if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&
(block_group->used || block_group->reserved)) {
ret = 1;
goto out;
}
/*
* Do not allow currently used block group to be the data relocation
* dedicated block group.
*/
if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg &&
(block_group->used || block_group->reserved)) {
ret = 1;
goto out;
}
WARN_ON_ONCE(block_group->alloc_offset > block_group->zone_capacity);
avail = block_group->zone_capacity - block_group->alloc_offset;
if (avail < num_bytes) {
if (ffe_ctl->max_extent_size < avail) {
/*
* With sequential allocator, free space is always
* contiguous
*/
ffe_ctl->max_extent_size = avail;
ffe_ctl->total_free_space = avail;
}
ret = 1;
goto out;
}
if (ffe_ctl->for_treelog && !fs_info->treelog_bg)
fs_info->treelog_bg = block_group->start;
if (ffe_ctl->for_data_reloc) {
if (!fs_info->data_reloc_bg)
fs_info->data_reloc_bg = block_group->start;
/*
* Do not allow allocations from this block group, unless it is
* for data relocation. Compared to increasing the ->ro, setting
* the ->zoned_data_reloc_ongoing flag still allows nocow
* writers to come in. See btrfs_inc_nocow_writers().
*
* We need to disable an allocation to avoid an allocation of
* regular (non-relocation data) extent. With mix of relocation
* extents and regular extents, we can dispatch WRITE commands
* (for relocation extents) and ZONE APPEND commands (for
* regular extents) at the same time to the same zone, which
* easily break the write pointer.
*
* Also, this flag avoids this block group to be zone finished.
*/
set_bit(BLOCK_GROUP_FLAG_ZONED_DATA_RELOC, &block_group->runtime_flags);
}
ffe_ctl->found_offset = start + block_group->alloc_offset;
block_group->alloc_offset += num_bytes;
spin_lock(&ctl->tree_lock);
ctl->free_space -= num_bytes;
spin_unlock(&ctl->tree_lock);
/*
* We do not check if found_offset is aligned to stripesize. The
* address is anyway rewritten when using zone append writing.
*/
ffe_ctl->search_start = ffe_ctl->found_offset;
out:
if (ret && ffe_ctl->for_treelog)
fs_info->treelog_bg = 0;
if (ret && ffe_ctl->for_data_reloc)
fs_info->data_reloc_bg = 0;
spin_unlock(&fs_info->relocation_bg_lock);
spin_unlock(&fs_info->treelog_bg_lock);
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
return ret;
}
static int do_allocation(struct btrfs_block_group *block_group,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group **bg_ret)
{
switch (ffe_ctl->policy) {
case BTRFS_EXTENT_ALLOC_CLUSTERED:
return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
case BTRFS_EXTENT_ALLOC_ZONED:
return do_allocation_zoned(block_group, ffe_ctl, bg_ret);
default:
BUG();
}
}
static void release_block_group(struct btrfs_block_group *block_group,
struct find_free_extent_ctl *ffe_ctl,
int delalloc)
{
switch (ffe_ctl->policy) {
case BTRFS_EXTENT_ALLOC_CLUSTERED:
ffe_ctl->retry_uncached = false;
break;
case BTRFS_EXTENT_ALLOC_ZONED:
/* Nothing to do */
break;
default:
BUG();
}
BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
ffe_ctl->index);
btrfs_release_block_group(block_group, delalloc);
}
static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,
struct btrfs_key *ins)
{
struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
if (!ffe_ctl->use_cluster && last_ptr) {
spin_lock(&last_ptr->lock);
last_ptr->window_start = ins->objectid;
spin_unlock(&last_ptr->lock);
}
}
static void found_extent(struct find_free_extent_ctl *ffe_ctl,
struct btrfs_key *ins)
{
switch (ffe_ctl->policy) {
case BTRFS_EXTENT_ALLOC_CLUSTERED:
found_extent_clustered(ffe_ctl, ins);
break;
case BTRFS_EXTENT_ALLOC_ZONED:
/* Nothing to do */
break;
default:
BUG();
}
}
static int can_allocate_chunk_zoned(struct btrfs_fs_info *fs_info,
struct find_free_extent_ctl *ffe_ctl)
{
/* Block group's activeness is not a requirement for METADATA block groups. */
if (!(ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA))
return 0;
/* If we can activate new zone, just allocate a chunk and use it */
if (btrfs_can_activate_zone(fs_info->fs_devices, ffe_ctl->flags))
return 0;
/*
* We already reached the max active zones. Try to finish one block
* group to make a room for a new block group. This is only possible
* for a data block group because btrfs_zone_finish() may need to wait
* for a running transaction which can cause a deadlock for metadata
* allocation.
*/
if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
int ret = btrfs_zone_finish_one_bg(fs_info);
if (ret == 1)
return 0;
else if (ret < 0)
return ret;
}
/*
* If we have enough free space left in an already active block group
* and we can't activate any other zone now, do not allow allocating a
* new chunk and let find_free_extent() retry with a smaller size.
*/
if (ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size)
return -ENOSPC;
/*
* Even min_alloc_size is not left in any block groups. Since we cannot
* activate a new block group, allocating it may not help. Let's tell a
* caller to try again and hope it progress something by writing some
* parts of the region. That is only possible for data block groups,
* where a part of the region can be written.
*/
if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA)
return -EAGAIN;
/*
* We cannot activate a new block group and no enough space left in any
* block groups. So, allocating a new block group may not help. But,
* there is nothing to do anyway, so let's go with it.
*/
return 0;
}
static int can_allocate_chunk(struct btrfs_fs_info *fs_info,
struct find_free_extent_ctl *ffe_ctl)
{
switch (ffe_ctl->policy) {
case BTRFS_EXTENT_ALLOC_CLUSTERED:
return 0;
case BTRFS_EXTENT_ALLOC_ZONED:
return can_allocate_chunk_zoned(fs_info, ffe_ctl);
default:
BUG();
}
}
/*
* Return >0 means caller needs to re-search for free extent
* Return 0 means we have the needed free extent.
* Return <0 means we failed to locate any free extent.
*/
static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
struct btrfs_key *ins,
struct find_free_extent_ctl *ffe_ctl,
bool full_search)
{
struct btrfs_root *root = fs_info->chunk_root;
int ret;
if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
ffe_ctl->orig_have_caching_bg = true;
if (ins->objectid) {
found_extent(ffe_ctl, ins);
return 0;
}
if (ffe_ctl->loop >= LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
return 1;
ffe_ctl->index++;
if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)
return 1;
/* See the comments for btrfs_loop_type for an explanation of the phases. */
if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
ffe_ctl->index = 0;
/*
* We want to skip the LOOP_CACHING_WAIT step if we don't have
* any uncached bgs and we've already done a full search
* through.
*/
if (ffe_ctl->loop == LOOP_CACHING_NOWAIT &&
(!ffe_ctl->orig_have_caching_bg && full_search))
ffe_ctl->loop++;
ffe_ctl->loop++;
if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
struct btrfs_trans_handle *trans;
int exist = 0;
/* Check if allocation policy allows to create a new chunk */
ret = can_allocate_chunk(fs_info, ffe_ctl);
if (ret)
return ret;
trans = current->journal_info;
if (trans)
exist = 1;
else
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
return ret;
}
ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
CHUNK_ALLOC_FORCE_FOR_EXTENT);
/* Do not bail out on ENOSPC since we can do more. */
if (ret == -ENOSPC) {
ret = 0;
ffe_ctl->loop++;
}
else if (ret < 0)
btrfs_abort_transaction(trans, ret);
else
ret = 0;
if (!exist)
btrfs_end_transaction(trans);
if (ret)
return ret;
}
if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)
return -ENOSPC;
/*
* Don't loop again if we already have no empty_size and
* no empty_cluster.
*/
if (ffe_ctl->empty_size == 0 &&
ffe_ctl->empty_cluster == 0)
return -ENOSPC;
ffe_ctl->empty_size = 0;
ffe_ctl->empty_cluster = 0;
}
return 1;
}
return -ENOSPC;
}
static bool find_free_extent_check_size_class(struct find_free_extent_ctl *ffe_ctl,
struct btrfs_block_group *bg)
{
if (ffe_ctl->policy == BTRFS_EXTENT_ALLOC_ZONED)
return true;
if (!btrfs_block_group_should_use_size_class(bg))
return true;
if (ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS)
return true;
if (ffe_ctl->loop >= LOOP_UNSET_SIZE_CLASS &&
bg->size_class == BTRFS_BG_SZ_NONE)
return true;
return ffe_ctl->size_class == bg->size_class;
}
static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_space_info *space_info,
struct btrfs_key *ins)
{
/*
* If our free space is heavily fragmented we may not be able to make
* big contiguous allocations, so instead of doing the expensive search
* for free space, simply return ENOSPC with our max_extent_size so we
* can go ahead and search for a more manageable chunk.
*
* If our max_extent_size is large enough for our allocation simply
* disable clustering since we will likely not be able to find enough
* space to create a cluster and induce latency trying.
*/
if (space_info->max_extent_size) {
spin_lock(&space_info->lock);
if (space_info->max_extent_size &&
ffe_ctl->num_bytes > space_info->max_extent_size) {
ins->offset = space_info->max_extent_size;
spin_unlock(&space_info->lock);
return -ENOSPC;
} else if (space_info->max_extent_size) {
ffe_ctl->use_cluster = false;
}
spin_unlock(&space_info->lock);
}
ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,
&ffe_ctl->empty_cluster);
if (ffe_ctl->last_ptr) {
struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
spin_lock(&last_ptr->lock);
if (last_ptr->block_group)
ffe_ctl->hint_byte = last_ptr->window_start;
if (last_ptr->fragmented) {
/*
* We still set window_start so we can keep track of the
* last place we found an allocation to try and save
* some time.
*/
ffe_ctl->hint_byte = last_ptr->window_start;
ffe_ctl->use_cluster = false;
}
spin_unlock(&last_ptr->lock);
}
return 0;
}
static int prepare_allocation_zoned(struct btrfs_fs_info *fs_info,
struct find_free_extent_ctl *ffe_ctl)
{
if (ffe_ctl->for_treelog) {
spin_lock(&fs_info->treelog_bg_lock);
if (fs_info->treelog_bg)
ffe_ctl->hint_byte = fs_info->treelog_bg;
spin_unlock(&fs_info->treelog_bg_lock);
} else if (ffe_ctl->for_data_reloc) {
spin_lock(&fs_info->relocation_bg_lock);
if (fs_info->data_reloc_bg)
ffe_ctl->hint_byte = fs_info->data_reloc_bg;
spin_unlock(&fs_info->relocation_bg_lock);
} else if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
struct btrfs_block_group *block_group;
spin_lock(&fs_info->zone_active_bgs_lock);
list_for_each_entry(block_group, &fs_info->zone_active_bgs, active_bg_list) {
/*
* No lock is OK here because avail is monotinically
* decreasing, and this is just a hint.
*/
u64 avail = block_group->zone_capacity - block_group->alloc_offset;
if (block_group_bits(block_group, ffe_ctl->flags) &&
avail >= ffe_ctl->num_bytes) {
ffe_ctl->hint_byte = block_group->start;
break;
}
}
spin_unlock(&fs_info->zone_active_bgs_lock);
}
return 0;
}
static int prepare_allocation(struct btrfs_fs_info *fs_info,
struct find_free_extent_ctl *ffe_ctl,
struct btrfs_space_info *space_info,
struct btrfs_key *ins)
{
switch (ffe_ctl->policy) {
case BTRFS_EXTENT_ALLOC_CLUSTERED:
return prepare_allocation_clustered(fs_info, ffe_ctl,
space_info, ins);
case BTRFS_EXTENT_ALLOC_ZONED:
return prepare_allocation_zoned(fs_info, ffe_ctl);
default:
BUG();
}
}
/*
* walks the btree of allocated extents and find a hole of a given size.
* The key ins is changed to record the hole:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
* Any available blocks before search_start are skipped.
*
* If there is no suitable free space, we will record the max size of
* the free space extent currently.
*
* The overall logic and call chain:
*
* find_free_extent()
* |- Iterate through all block groups
* | |- Get a valid block group
* | |- Try to do clustered allocation in that block group
* | |- Try to do unclustered allocation in that block group
* | |- Check if the result is valid
* | | |- If valid, then exit
* | |- Jump to next block group
* |
* |- Push harder to find free extents
* |- If not found, re-iterate all block groups
*/
static noinline int find_free_extent(struct btrfs_root *root,
struct btrfs_key *ins,
struct find_free_extent_ctl *ffe_ctl)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret = 0;
int cache_block_group_error = 0;
struct btrfs_block_group *block_group = NULL;
struct btrfs_space_info *space_info;
bool full_search = false;
WARN_ON(ffe_ctl->num_bytes < fs_info->sectorsize);
ffe_ctl->search_start = 0;
/* For clustered allocation */
ffe_ctl->empty_cluster = 0;
ffe_ctl->last_ptr = NULL;
ffe_ctl->use_cluster = true;
ffe_ctl->have_caching_bg = false;
ffe_ctl->orig_have_caching_bg = false;
ffe_ctl->index = btrfs_bg_flags_to_raid_index(ffe_ctl->flags);
ffe_ctl->loop = 0;
ffe_ctl->retry_uncached = false;
ffe_ctl->cached = 0;
ffe_ctl->max_extent_size = 0;
ffe_ctl->total_free_space = 0;
ffe_ctl->found_offset = 0;
ffe_ctl->policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
ffe_ctl->size_class = btrfs_calc_block_group_size_class(ffe_ctl->num_bytes);
if (btrfs_is_zoned(fs_info))
ffe_ctl->policy = BTRFS_EXTENT_ALLOC_ZONED;
ins->type = BTRFS_EXTENT_ITEM_KEY;
ins->objectid = 0;
ins->offset = 0;
trace_find_free_extent(root, ffe_ctl);
space_info = btrfs_find_space_info(fs_info, ffe_ctl->flags);
if (!space_info) {
btrfs_err(fs_info, "No space info for %llu", ffe_ctl->flags);
return -ENOSPC;
}
ret = prepare_allocation(fs_info, ffe_ctl, space_info, ins);
if (ret < 0)
return ret;
ffe_ctl->search_start = max(ffe_ctl->search_start,
first_logical_byte(fs_info));
ffe_ctl->search_start = max(ffe_ctl->search_start, ffe_ctl->hint_byte);
if (ffe_ctl->search_start == ffe_ctl->hint_byte) {
block_group = btrfs_lookup_block_group(fs_info,
ffe_ctl->search_start);
/*
* we don't want to use the block group if it doesn't match our
* allocation bits, or if its not cached.
*
* However if we are re-searching with an ideal block group
* picked out then we don't care that the block group is cached.
*/
if (block_group && block_group_bits(block_group, ffe_ctl->flags) &&
block_group->cached != BTRFS_CACHE_NO) {
down_read(&space_info->groups_sem);
if (list_empty(&block_group->list) ||
block_group->ro) {
/*
* someone is removing this block group,
* we can't jump into the have_block_group
* target because our list pointers are not
* valid
*/
btrfs_put_block_group(block_group);
up_read(&space_info->groups_sem);
} else {
ffe_ctl->index = btrfs_bg_flags_to_raid_index(
block_group->flags);
btrfs_lock_block_group(block_group,
ffe_ctl->delalloc);
ffe_ctl->hinted = true;
goto have_block_group;
}
} else if (block_group) {
btrfs_put_block_group(block_group);
}
}
search:
trace_find_free_extent_search_loop(root, ffe_ctl);
ffe_ctl->have_caching_bg = false;
if (ffe_ctl->index == btrfs_bg_flags_to_raid_index(ffe_ctl->flags) ||
ffe_ctl->index == 0)
full_search = true;
down_read(&space_info->groups_sem);
list_for_each_entry(block_group,
&space_info->block_groups[ffe_ctl->index], list) {
struct btrfs_block_group *bg_ret;
ffe_ctl->hinted = false;
/* If the block group is read-only, we can skip it entirely. */
if (unlikely(block_group->ro)) {
if (ffe_ctl->for_treelog)
btrfs_clear_treelog_bg(block_group);
if (ffe_ctl->for_data_reloc)
btrfs_clear_data_reloc_bg(block_group);
continue;
}
btrfs_grab_block_group(block_group, ffe_ctl->delalloc);
ffe_ctl->search_start = block_group->start;
/*
* this can happen if we end up cycling through all the
* raid types, but we want to make sure we only allocate
* for the proper type.
*/
if (!block_group_bits(block_group, ffe_ctl->flags)) {
u64 extra = BTRFS_BLOCK_GROUP_DUP |
BTRFS_BLOCK_GROUP_RAID1_MASK |
BTRFS_BLOCK_GROUP_RAID56_MASK |
BTRFS_BLOCK_GROUP_RAID10;
/*
* if they asked for extra copies and this block group
* doesn't provide them, bail. This does allow us to
* fill raid0 from raid1.
*/
if ((ffe_ctl->flags & extra) && !(block_group->flags & extra))
goto loop;
/*
* This block group has different flags than we want.
* It's possible that we have MIXED_GROUP flag but no
* block group is mixed. Just skip such block group.
*/
btrfs_release_block_group(block_group, ffe_ctl->delalloc);
continue;
}
have_block_group:
trace_find_free_extent_have_block_group(root, ffe_ctl, block_group);
ffe_ctl->cached = btrfs_block_group_done(block_group);
if (unlikely(!ffe_ctl->cached)) {
ffe_ctl->have_caching_bg = true;
ret = btrfs_cache_block_group(block_group, false);
/*
* If we get ENOMEM here or something else we want to
* try other block groups, because it may not be fatal.
* However if we can't find anything else we need to
* save our return here so that we return the actual
* error that caused problems, not ENOSPC.
*/
if (ret < 0) {
if (!cache_block_group_error)
cache_block_group_error = ret;
ret = 0;
goto loop;
}
ret = 0;
}
if (unlikely(block_group->cached == BTRFS_CACHE_ERROR)) {
if (!cache_block_group_error)
cache_block_group_error = -EIO;
goto loop;
}
if (!find_free_extent_check_size_class(ffe_ctl, block_group))
goto loop;
bg_ret = NULL;
ret = do_allocation(block_group, ffe_ctl, &bg_ret);
if (ret > 0)
goto loop;
if (bg_ret && bg_ret != block_group) {
btrfs_release_block_group(block_group, ffe_ctl->delalloc);
block_group = bg_ret;
}
/* Checks */
ffe_ctl->search_start = round_up(ffe_ctl->found_offset,
fs_info->stripesize);
/* move on to the next group */
if (ffe_ctl->search_start + ffe_ctl->num_bytes >
block_group->start + block_group->length) {
btrfs_add_free_space_unused(block_group,
ffe_ctl->found_offset,
ffe_ctl->num_bytes);
goto loop;
}
if (ffe_ctl->found_offset < ffe_ctl->search_start)
btrfs_add_free_space_unused(block_group,
ffe_ctl->found_offset,
ffe_ctl->search_start - ffe_ctl->found_offset);
ret = btrfs_add_reserved_bytes(block_group, ffe_ctl->ram_bytes,
ffe_ctl->num_bytes,
ffe_ctl->delalloc,
ffe_ctl->loop >= LOOP_WRONG_SIZE_CLASS);
if (ret == -EAGAIN) {
btrfs_add_free_space_unused(block_group,
ffe_ctl->found_offset,
ffe_ctl->num_bytes);
goto loop;
}
btrfs_inc_block_group_reservations(block_group);
/* we are all good, lets return */
ins->objectid = ffe_ctl->search_start;
ins->offset = ffe_ctl->num_bytes;
trace_btrfs_reserve_extent(block_group, ffe_ctl);
btrfs_release_block_group(block_group, ffe_ctl->delalloc);
break;
loop:
if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
!ffe_ctl->retry_uncached) {
ffe_ctl->retry_uncached = true;
btrfs_wait_block_group_cache_progress(block_group,
ffe_ctl->num_bytes +
ffe_ctl->empty_cluster +
ffe_ctl->empty_size);
goto have_block_group;
}
release_block_group(block_group, ffe_ctl, ffe_ctl->delalloc);
cond_resched();
}
up_read(&space_info->groups_sem);
ret = find_free_extent_update_loop(fs_info, ins, ffe_ctl, full_search);
if (ret > 0)
goto search;
if (ret == -ENOSPC && !cache_block_group_error) {
/*
* Use ffe_ctl->total_free_space as fallback if we can't find
* any contiguous hole.
*/
if (!ffe_ctl->max_extent_size)
ffe_ctl->max_extent_size = ffe_ctl->total_free_space;
spin_lock(&space_info->lock);
space_info->max_extent_size = ffe_ctl->max_extent_size;
spin_unlock(&space_info->lock);
ins->offset = ffe_ctl->max_extent_size;
} else if (ret == -ENOSPC) {
ret = cache_block_group_error;
}
return ret;
}
/*
* Entry point to the extent allocator. Tries to find a hole that is at least
* as big as @num_bytes.
*
* @root - The root that will contain this extent
*
* @ram_bytes - The amount of space in ram that @num_bytes take. This
* is used for accounting purposes. This value differs
* from @num_bytes only in the case of compressed extents.
*
* @num_bytes - Number of bytes to allocate on-disk.
*
* @min_alloc_size - Indicates the minimum amount of space that the
* allocator should try to satisfy. In some cases
* @num_bytes may be larger than what is required and if
* the filesystem is fragmented then allocation fails.
* However, the presence of @min_alloc_size gives a
* chance to try and satisfy the smaller allocation.
*
* @empty_size - A hint that you plan on doing more COW. This is the
* size in bytes the allocator should try to find free
* next to the block it returns. This is just a hint and
* may be ignored by the allocator.
*
* @hint_byte - Hint to the allocator to start searching above the byte
* address passed. It might be ignored.
*
* @ins - This key is modified to record the found hole. It will
* have the following values:
* ins->objectid == start position
* ins->flags = BTRFS_EXTENT_ITEM_KEY
* ins->offset == the size of the hole.
*
* @is_data - Boolean flag indicating whether an extent is
* allocated for data (true) or metadata (false)
*
* @delalloc - Boolean flag indicating whether this allocation is for
* delalloc or not. If 'true' data_rwsem of block groups
* is going to be acquired.
*
*
* Returns 0 when an allocation succeeded or < 0 when an error occurred. In
* case -ENOSPC is returned then @ins->offset will contain the size of the
* largest available hole the allocator managed to find.
*/
int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
u64 num_bytes, u64 min_alloc_size,
u64 empty_size, u64 hint_byte,
struct btrfs_key *ins, int is_data, int delalloc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct find_free_extent_ctl ffe_ctl = {};
bool final_tried = num_bytes == min_alloc_size;
u64 flags;
int ret;
bool for_treelog = (btrfs_root_id(root) == BTRFS_TREE_LOG_OBJECTID);
bool for_data_reloc = (btrfs_is_data_reloc_root(root) && is_data);
flags = get_alloc_profile_by_root(root, is_data);
again:
WARN_ON(num_bytes < fs_info->sectorsize);
ffe_ctl.ram_bytes = ram_bytes;
ffe_ctl.num_bytes = num_bytes;
ffe_ctl.min_alloc_size = min_alloc_size;
ffe_ctl.empty_size = empty_size;
ffe_ctl.flags = flags;
ffe_ctl.delalloc = delalloc;
ffe_ctl.hint_byte = hint_byte;
ffe_ctl.for_treelog = for_treelog;
ffe_ctl.for_data_reloc = for_data_reloc;
ret = find_free_extent(root, ins, &ffe_ctl);
if (!ret && !is_data) {
btrfs_dec_block_group_reservations(fs_info, ins->objectid);
} else if (ret == -ENOSPC) {
if (!final_tried && ins->offset) {
num_bytes = min(num_bytes >> 1, ins->offset);
num_bytes = round_down(num_bytes,
fs_info->sectorsize);
num_bytes = max(num_bytes, min_alloc_size);
ram_bytes = num_bytes;
if (num_bytes == min_alloc_size)
final_tried = true;
goto again;
} else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
struct btrfs_space_info *sinfo;
sinfo = btrfs_find_space_info(fs_info, flags);
btrfs_err(fs_info,
"allocation failed flags %llu, wanted %llu tree-log %d, relocation: %d",
flags, num_bytes, for_treelog, for_data_reloc);
if (sinfo)
btrfs_dump_space_info(fs_info, sinfo,
num_bytes, 1);
}
}
return ret;
}
int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
u64 start, u64 len, int delalloc)
{
struct btrfs_block_group *cache;
cache = btrfs_lookup_block_group(fs_info, start);
if (!cache) {
btrfs_err(fs_info, "Unable to find block group for %llu",
start);
return -ENOSPC;
}
btrfs_add_free_space(cache, start, len);
btrfs_free_reserved_bytes(cache, len, delalloc);
trace_btrfs_reserved_extent_free(fs_info, start, len);
btrfs_put_block_group(cache);
return 0;
}
int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans,
const struct extent_buffer *eb)
{
struct btrfs_block_group *cache;
int ret = 0;
cache = btrfs_lookup_block_group(trans->fs_info, eb->start);
if (!cache) {
btrfs_err(trans->fs_info, "unable to find block group for %llu",
eb->start);
return -ENOSPC;
}
ret = pin_down_extent(trans, cache, eb->start, eb->len, 1);
btrfs_put_block_group(cache);
return ret;
}
static int alloc_reserved_extent(struct btrfs_trans_handle *trans, u64 bytenr,
u64 num_bytes)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
ret = remove_from_free_space_tree(trans, bytenr, num_bytes);
if (ret)
return ret;
ret = btrfs_update_block_group(trans, bytenr, num_bytes, true);
if (ret) {
ASSERT(!ret);
btrfs_err(fs_info, "update block group failed for %llu %llu",
bytenr, num_bytes);
return ret;
}
trace_btrfs_reserved_extent_alloc(fs_info, bytenr, num_bytes);
return 0;
}
static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
u64 flags, u64 owner, u64 offset,
struct btrfs_key *ins, int ref_mod, u64 oref_root)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *extent_root;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_extent_owner_ref *oref;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
int type;
u32 size;
const bool simple_quota = (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE);
if (parent > 0)
type = BTRFS_SHARED_DATA_REF_KEY;
else
type = BTRFS_EXTENT_DATA_REF_KEY;
size = sizeof(*extent_item);
if (simple_quota)
size += btrfs_extent_inline_ref_size(BTRFS_EXTENT_OWNER_REF_KEY);
size += btrfs_extent_inline_ref_size(type);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
extent_root = btrfs_extent_root(fs_info, ins->objectid);
ret = btrfs_insert_empty_item(trans, extent_root, path, ins, size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, ref_mod);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_DATA);
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
if (simple_quota) {
btrfs_set_extent_inline_ref_type(leaf, iref, BTRFS_EXTENT_OWNER_REF_KEY);
oref = (struct btrfs_extent_owner_ref *)(&iref->offset);
btrfs_set_extent_owner_ref_root_id(leaf, oref, oref_root);
iref = (struct btrfs_extent_inline_ref *)(oref + 1);
}
btrfs_set_extent_inline_ref_type(leaf, iref, type);
if (parent > 0) {
struct btrfs_shared_data_ref *ref;
ref = (struct btrfs_shared_data_ref *)(iref + 1);
btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
} else {
struct btrfs_extent_data_ref *ref;
ref = (struct btrfs_extent_data_ref *)(&iref->offset);
btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
btrfs_set_extent_data_ref_offset(leaf, ref, offset);
btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
}
btrfs_mark_buffer_dirty(trans, path->nodes[0]);
btrfs_free_path(path);
return alloc_reserved_extent(trans, ins->objectid, ins->offset);
}
static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *node,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *extent_root;
int ret;
struct btrfs_extent_item *extent_item;
struct btrfs_key extent_key;
struct btrfs_tree_block_info *block_info;
struct btrfs_extent_inline_ref *iref;
struct btrfs_path *path;
struct extent_buffer *leaf;
u32 size = sizeof(*extent_item) + sizeof(*iref);
const u64 flags = (extent_op ? extent_op->flags_to_set : 0);
/* The owner of a tree block is the level. */
int level = btrfs_delayed_ref_owner(node);
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
extent_key.objectid = node->bytenr;
if (skinny_metadata) {
/* The owner of a tree block is the level. */
extent_key.offset = level;
extent_key.type = BTRFS_METADATA_ITEM_KEY;
} else {
extent_key.offset = node->num_bytes;
extent_key.type = BTRFS_EXTENT_ITEM_KEY;
size += sizeof(*block_info);
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
extent_root = btrfs_extent_root(fs_info, extent_key.objectid);
ret = btrfs_insert_empty_item(trans, extent_root, path, &extent_key,
size);
if (ret) {
btrfs_free_path(path);
return ret;
}
leaf = path->nodes[0];
extent_item = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_extent_item);
btrfs_set_extent_refs(leaf, extent_item, 1);
btrfs_set_extent_generation(leaf, extent_item, trans->transid);
btrfs_set_extent_flags(leaf, extent_item,
flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
if (skinny_metadata) {
iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
} else {
block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
btrfs_set_tree_block_level(leaf, block_info, level);
iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
}
if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_SHARED_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, node->parent);
} else {
btrfs_set_extent_inline_ref_type(leaf, iref,
BTRFS_TREE_BLOCK_REF_KEY);
btrfs_set_extent_inline_ref_offset(leaf, iref, node->ref_root);
}
btrfs_mark_buffer_dirty(trans, leaf);
btrfs_free_path(path);
return alloc_reserved_extent(trans, node->bytenr, fs_info->nodesize);
}
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner,
u64 offset, u64 ram_bytes,
struct btrfs_key *ins)
{
struct btrfs_ref generic_ref = {
.action = BTRFS_ADD_DELAYED_EXTENT,
.bytenr = ins->objectid,
.num_bytes = ins->offset,
.owning_root = btrfs_root_id(root),
.ref_root = btrfs_root_id(root),
};
ASSERT(generic_ref.ref_root != BTRFS_TREE_LOG_OBJECTID);
if (btrfs_is_data_reloc_root(root) && is_fstree(root->relocation_src_root))
generic_ref.owning_root = root->relocation_src_root;
btrfs_init_data_ref(&generic_ref, owner, offset, 0, false);
btrfs_ref_tree_mod(root->fs_info, &generic_ref);
return btrfs_add_delayed_data_ref(trans, &generic_ref, ram_bytes);
}
/*
* this is used by the tree logging recovery code. It records that
* an extent has been allocated and makes sure to clear the free
* space cache bits as well
*/
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
u64 root_objectid, u64 owner, u64 offset,
struct btrfs_key *ins)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
int ret;
struct btrfs_block_group *block_group;
struct btrfs_space_info *space_info;
struct btrfs_squota_delta delta = {
.root = root_objectid,
.num_bytes = ins->offset,
.generation = trans->transid,
.is_data = true,
.is_inc = true,
};
/*
* Mixed block groups will exclude before processing the log so we only
* need to do the exclude dance if this fs isn't mixed.
*/
if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
ret = __exclude_logged_extent(fs_info, ins->objectid,
ins->offset);
if (ret)
return ret;
}
block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
if (!block_group)
return -EINVAL;
space_info = block_group->space_info;
spin_lock(&space_info->lock);
spin_lock(&block_group->lock);
space_info->bytes_reserved += ins->offset;
block_group->reserved += ins->offset;
spin_unlock(&block_group->lock);
spin_unlock(&space_info->lock);
ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
offset, ins, 1, root_objectid);
if (ret)
btrfs_pin_extent(trans, ins->objectid, ins->offset, 1);
ret = btrfs_record_squota_delta(fs_info, &delta);
btrfs_put_block_group(block_group);
return ret;
}
#ifdef CONFIG_BTRFS_DEBUG
/*
* Extra safety check in case the extent tree is corrupted and extent allocator
* chooses to use a tree block which is already used and locked.
*/
static bool check_eb_lock_owner(const struct extent_buffer *eb)
{
if (eb->lock_owner == current->pid) {
btrfs_err_rl(eb->fs_info,
"tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
eb->start, btrfs_header_owner(eb), current->pid);
return true;
}
return false;
}
#else
static bool check_eb_lock_owner(struct extent_buffer *eb)
{
return false;
}
#endif
static struct extent_buffer *
btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
u64 bytenr, int level, u64 owner,
enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *buf;
u64 lockdep_owner = owner;
buf = btrfs_find_create_tree_block(fs_info, bytenr, owner, level);
if (IS_ERR(buf))
return buf;
if (check_eb_lock_owner(buf)) {
free_extent_buffer(buf);
return ERR_PTR(-EUCLEAN);
}
/*
* The reloc trees are just snapshots, so we need them to appear to be
* just like any other fs tree WRT lockdep.
*
* The exception however is in replace_path() in relocation, where we
* hold the lock on the original fs root and then search for the reloc
* root. At that point we need to make sure any reloc root buffers are
* set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make
* lockdep happy.
*/
if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&
!test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
lockdep_owner = BTRFS_FS_TREE_OBJECTID;
/* btrfs_clear_buffer_dirty() accesses generation field. */
btrfs_set_header_generation(buf, trans->transid);
/*
* This needs to stay, because we could allocate a freed block from an
* old tree into a new tree, so we need to make sure this new block is
* set to the appropriate level and owner.
*/
btrfs_set_buffer_lockdep_class(lockdep_owner, buf, level);
btrfs_tree_lock_nested(buf, nest);
btrfs_clear_buffer_dirty(trans, buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
clear_bit(EXTENT_BUFFER_ZONED_ZEROOUT, &buf->bflags);
set_extent_buffer_uptodate(buf);
memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
btrfs_set_header_level(buf, level);
btrfs_set_header_bytenr(buf, buf->start);
btrfs_set_header_generation(buf, trans->transid);
btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
btrfs_set_header_owner(buf, owner);
write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
if (btrfs_root_id(root) == BTRFS_TREE_LOG_OBJECTID) {
buf->log_index = root->log_transid % 2;
/*
* we allow two log transactions at a time, use different
* EXTENT bit to differentiate dirty pages.
*/
if (buf->log_index == 0)
set_extent_bit(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1,
EXTENT_DIRTY, NULL);
else
set_extent_bit(&root->dirty_log_pages, buf->start,
buf->start + buf->len - 1,
EXTENT_NEW, NULL);
} else {
buf->log_index = -1;
set_extent_bit(&trans->transaction->dirty_pages, buf->start,
buf->start + buf->len - 1, EXTENT_DIRTY, NULL);
}
/* this returns a buffer locked for blocking */
return buf;
}
/*
* finds a free extent and does all the dirty work required for allocation
* returns the tree buffer or an ERR_PTR on error.
*/
struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
u64 empty_size,
u64 reloc_src_root,
enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key ins;
struct btrfs_block_rsv *block_rsv;
struct extent_buffer *buf;
u64 flags = 0;
int ret;
u32 blocksize = fs_info->nodesize;
bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
u64 owning_root;
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (btrfs_is_testing(fs_info)) {
buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
level, root_objectid, nest);
if (!IS_ERR(buf))
root->alloc_bytenr += blocksize;
return buf;
}
#endif
block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
if (IS_ERR(block_rsv))
return ERR_CAST(block_rsv);
ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
empty_size, hint, &ins, 0, 0);
if (ret)
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
root_objectid, nest);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;
}
owning_root = btrfs_header_owner(buf);
if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
if (parent == 0)
parent = ins.objectid;
flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
owning_root = reloc_src_root;
} else
BUG_ON(parent > 0);
if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
struct btrfs_delayed_extent_op *extent_op;
struct btrfs_ref generic_ref = {
.action = BTRFS_ADD_DELAYED_EXTENT,
.bytenr = ins.objectid,
.num_bytes = ins.offset,
.parent = parent,
.owning_root = owning_root,
.ref_root = root_objectid,
};
if (!skinny_metadata || flags != 0) {
extent_op = btrfs_alloc_delayed_extent_op();
if (!extent_op) {
ret = -ENOMEM;
goto out_free_buf;
}
if (key)
memcpy(&extent_op->key, key, sizeof(extent_op->key));
else
memset(&extent_op->key, 0, sizeof(extent_op->key));
extent_op->flags_to_set = flags;
extent_op->update_key = (skinny_metadata ? false : true);
extent_op->update_flags = (flags != 0);
} else {
extent_op = NULL;
}
btrfs_init_tree_ref(&generic_ref, level, btrfs_root_id(root), false);
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op);
if (ret) {
btrfs_free_delayed_extent_op(extent_op);
goto out_free_buf;
}
}
return buf;
out_free_buf:
btrfs_tree_unlock(buf);
free_extent_buffer(buf);
out_free_reserved:
btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
out_unuse:
btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
return ERR_PTR(ret);
}
struct walk_control {
u64 refs[BTRFS_MAX_LEVEL];
u64 flags[BTRFS_MAX_LEVEL];
struct btrfs_key update_progress;
struct btrfs_key drop_progress;
int drop_level;
int stage;
int level;
int shared_level;
int update_ref;
int keep_locks;
int reada_slot;
int reada_count;
int restarted;
/* Indicate that extent info needs to be looked up when walking the tree. */
int lookup_info;
};
/*
* This is our normal stage. We are traversing blocks the current snapshot owns
* and we are dropping any of our references to any children we are able to, and
* then freeing the block once we've processed all of the children.
*/
#define DROP_REFERENCE 1
/*
* We enter this stage when we have to walk into a child block (meaning we can't
* simply drop our reference to it from our current parent node) and there are
* more than one reference on it. If we are the owner of any of the children
* blocks from the current parent node then we have to do the FULL_BACKREF dance
* on them in order to drop our normal ref and add the shared ref.
*/
#define UPDATE_BACKREF 2
/*
* Decide if we need to walk down into this node to adjust the references.
*
* @root: the root we are currently deleting
* @wc: the walk control for this deletion
* @eb: the parent eb that we're currently visiting
* @refs: the number of refs for wc->level - 1
* @flags: the flags for wc->level - 1
* @slot: the slot in the eb that we're currently checking
*
* This is meant to be called when we're evaluating if a node we point to at
* wc->level should be read and walked into, or if we can simply delete our
* reference to it. We return true if we should walk into the node, false if we
* can skip it.
*
* We have assertions in here to make sure this is called correctly. We assume
* that sanity checking on the blocks read to this point has been done, so any
* corrupted file systems must have been caught before calling this function.
*/
static bool visit_node_for_delete(struct btrfs_root *root, struct walk_control *wc,
struct extent_buffer *eb, u64 refs, u64 flags, int slot)
{
struct btrfs_key key;
u64 generation;
int level = wc->level;
ASSERT(level > 0);
ASSERT(wc->refs[level - 1] > 0);
/*
* The update backref stage we only want to skip if we already have
* FULL_BACKREF set, otherwise we need to read.
*/
if (wc->stage == UPDATE_BACKREF) {
if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
return false;
return true;
}
/*
* We're the last ref on this block, we must walk into it and process
* any refs it's pointing at.
*/
if (wc->refs[level - 1] == 1)
return true;
/*
* If we're already FULL_BACKREF then we know we can just drop our
* current reference.
*/
if (level == 1 && flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
return false;
/*
* This block is older than our creation generation, we can drop our
* reference to it.
*/
generation = btrfs_node_ptr_generation(eb, slot);
if (!wc->update_ref || generation <= root->root_key.offset)
return false;
/*
* This block was processed from a previous snapshot deletion run, we
* can skip it.
*/
btrfs_node_key_to_cpu(eb, &key, slot);
if (btrfs_comp_cpu_keys(&key, &wc->update_progress) < 0)
return false;
/* All other cases we need to wander into the node. */
return true;
}
static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct walk_control *wc,
struct btrfs_path *path)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 refs;
u64 flags;
u32 nritems;
struct extent_buffer *eb;
int ret;
int slot;
int nread = 0;
if (path->slots[wc->level] < wc->reada_slot) {
wc->reada_count = wc->reada_count * 2 / 3;
wc->reada_count = max(wc->reada_count, 2);
} else {
wc->reada_count = wc->reada_count * 3 / 2;
wc->reada_count = min_t(int, wc->reada_count,
BTRFS_NODEPTRS_PER_BLOCK(fs_info));
}
eb = path->nodes[wc->level];
nritems = btrfs_header_nritems(eb);
for (slot = path->slots[wc->level]; slot < nritems; slot++) {
if (nread >= wc->reada_count)
break;
cond_resched();
bytenr = btrfs_node_blockptr(eb, slot);
generation = btrfs_node_ptr_generation(eb, slot);
if (slot == path->slots[wc->level])
goto reada;
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset)
continue;
/* We don't lock the tree block, it's OK to be racy here */
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
wc->level - 1, 1, &refs,
&flags, NULL);
/* We don't care about errors in readahead. */
if (ret < 0)
continue;
/*
* This could be racey, it's conceivable that we raced and end
* up with a bogus refs count, if that's the case just skip, if
* we are actually corrupt we will notice when we look up
* everything again with our locks.
*/
if (refs == 0)
continue;
/* If we don't need to visit this node don't reada. */
if (!visit_node_for_delete(root, wc, eb, refs, flags, slot))
continue;
reada:
btrfs_readahead_node_child(eb, slot);
nread++;
}
wc->reada_slot = slot;
}
/*
* helper to process tree block while walking down the tree.
*
* when wc->stage == UPDATE_BACKREF, this function updates
* back refs for pointers in the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
int ret;
if (wc->stage == UPDATE_BACKREF && btrfs_header_owner(eb) != btrfs_root_id(root))
return 1;
/*
* when reference count of tree block is 1, it won't increase
* again. once full backref flag is set, we never clear it.
*/
if (wc->lookup_info &&
((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
(wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
ASSERT(path->locks[level]);
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level],
NULL);
if (ret)
return ret;
if (unlikely(wc->refs[level] == 0)) {
btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
eb->start);
return -EUCLEAN;
}
}
if (wc->stage == DROP_REFERENCE) {
if (wc->refs[level] > 1)
return 1;
if (path->locks[level] && !wc->keep_locks) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/* wc->stage == UPDATE_BACKREF */
if (!(wc->flags[level] & flag)) {
ASSERT(path->locks[level]);
ret = btrfs_inc_ref(trans, root, eb, 1);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_dec_ref(trans, root, eb, 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = btrfs_set_disk_extent_flags(trans, eb, flag);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
wc->flags[level] |= flag;
}
/*
* the block is shared by multiple trees, so it's not good to
* keep the tree lock
*/
if (path->locks[level] && level > 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
}
return 0;
}
/*
* This is used to verify a ref exists for this root to deal with a bug where we
* would have a drop_progress key that hadn't been updated properly.
*/
static int check_ref_exists(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 bytenr, u64 parent,
int level)
{
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *head;
struct btrfs_path *path;
struct btrfs_extent_inline_ref *iref;
int ret;
bool exists = false;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
ret = lookup_extent_backref(trans, path, &iref, bytenr,
root->fs_info->nodesize, parent,
btrfs_root_id(root), level, 0);
if (ret != -ENOENT) {
/*
* If we get 0 then we found our reference, return 1, else
* return the error if it's not -ENOENT;
*/
btrfs_free_path(path);
return (ret < 0 ) ? ret : 1;
}
/*
* We could have a delayed ref with this reference, so look it up while
* we're holding the path open to make sure we don't race with the
* delayed ref running.
*/
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
if (!head)
goto out;
if (!mutex_trylock(&head->mutex)) {
/*
* We're contended, means that the delayed ref is running, get a
* reference and wait for the ref head to be complete and then
* try again.
*/
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
goto again;
}
exists = btrfs_find_delayed_tree_ref(head, root->root_key.objectid, parent);
mutex_unlock(&head->mutex);
out:
spin_unlock(&delayed_refs->lock);
btrfs_free_path(path);
return exists ? 1 : 0;
}
/*
* We may not have an uptodate block, so if we are going to walk down into this
* block we need to drop the lock, read it off of the disk, re-lock it and
* return to continue dropping the snapshot.
*/
static int check_next_block_uptodate(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc,
struct extent_buffer *next)
{
struct btrfs_tree_parent_check check = { 0 };
u64 generation;
int level = wc->level;
int ret;
btrfs_assert_tree_write_locked(next);
generation = btrfs_node_ptr_generation(path->nodes[level], path->slots[level]);
if (btrfs_buffer_uptodate(next, generation, 0))
return 0;
check.level = level - 1;
check.transid = generation;
check.owner_root = btrfs_root_id(root);
check.has_first_key = true;
btrfs_node_key_to_cpu(path->nodes[level], &check.first_key, path->slots[level]);
btrfs_tree_unlock(next);
if (level == 1)
reada_walk_down(trans, root, wc, path);
ret = btrfs_read_extent_buffer(next, &check);
if (ret) {
free_extent_buffer(next);
return ret;
}
btrfs_tree_lock(next);
wc->lookup_info = 1;
return 0;
}
/*
* If we determine that we don't have to visit wc->level - 1 then we need to
* determine if we can drop our reference.
*
* If we are UPDATE_BACKREF then we will not, we need to update our backrefs.
*
* If we are DROP_REFERENCE this will figure out if we need to drop our current
* reference, skipping it if we dropped it from a previous incompleted drop, or
* dropping it if we still have a reference to it.
*/
static int maybe_drop_reference(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_path *path, struct walk_control *wc,
struct extent_buffer *next, u64 owner_root)
{
struct btrfs_ref ref = {
.action = BTRFS_DROP_DELAYED_REF,
.bytenr = next->start,
.num_bytes = root->fs_info->nodesize,
.owning_root = owner_root,
.ref_root = btrfs_root_id(root),
};
int level = wc->level;
int ret;
/* We are UPDATE_BACKREF, we're not dropping anything. */
if (wc->stage == UPDATE_BACKREF)
return 0;
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
ref.parent = path->nodes[level]->start;
} else {
ASSERT(btrfs_root_id(root) == btrfs_header_owner(path->nodes[level]));
if (btrfs_root_id(root) != btrfs_header_owner(path->nodes[level])) {
btrfs_err(root->fs_info, "mismatched block owner");
return -EIO;
}
}
/*
* If we had a drop_progress we need to verify the refs are set as
* expected. If we find our ref then we know that from here on out
* everything should be correct, and we can clear the
* ->restarted flag.
*/
if (wc->restarted) {
ret = check_ref_exists(trans, root, next->start, ref.parent,
level - 1);
if (ret <= 0)
return ret;
ret = 0;
wc->restarted = 0;
}
/*
* Reloc tree doesn't contribute to qgroup numbers, and we have already
* accounted them at merge time (replace_path), thus we could skip
* expensive subtree trace here.
*/
if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID &&
wc->refs[level - 1] > 1) {
u64 generation = btrfs_node_ptr_generation(path->nodes[level],
path->slots[level]);
ret = btrfs_qgroup_trace_subtree(trans, next, generation, level - 1);
if (ret) {
btrfs_err_rl(root->fs_info,
"error %d accounting shared subtree, quota is out of sync, rescan required",
ret);
}
}
/*
* We need to update the next key in our walk control so we can update
* the drop_progress key accordingly. We don't care if find_next_key
* doesn't find a key because that means we're at the end and are going
* to clean up now.
*/
wc->drop_level = level;
find_next_key(path, level, &wc->drop_progress);
btrfs_init_tree_ref(&ref, level - 1, 0, false);
return btrfs_free_extent(trans, &ref);
}
/*
* helper to process tree block pointer.
*
* when wc->stage == DROP_REFERENCE, this function checks
* reference count of the block pointed to. if the block
* is shared and we need update back refs for the subtree
* rooted at the block, this function changes wc->stage to
* UPDATE_BACKREF. if the block is shared and there is no
* need to update back, this function drops the reference
* to the block.
*
* NOTE: return value 1 means we should stop walking down.
*/
static noinline int do_walk_down(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 bytenr;
u64 generation;
u64 owner_root = 0;
struct extent_buffer *next;
int level = wc->level;
int ret = 0;
generation = btrfs_node_ptr_generation(path->nodes[level],
path->slots[level]);
/*
* if the lower level block was created before the snapshot
* was created, we know there is no need to update back refs
* for the subtree
*/
if (wc->stage == UPDATE_BACKREF &&
generation <= root->root_key.offset) {
wc->lookup_info = 1;
return 1;
}
bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
next = btrfs_find_create_tree_block(fs_info, bytenr, btrfs_root_id(root),
level - 1);
if (IS_ERR(next))
return PTR_ERR(next);
btrfs_tree_lock(next);
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
&wc->refs[level - 1],
&wc->flags[level - 1],
&owner_root);
if (ret < 0)
goto out_unlock;
if (unlikely(wc->refs[level - 1] == 0)) {
btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
bytenr);
ret = -EUCLEAN;
goto out_unlock;
}
wc->lookup_info = 0;
/* If we don't have to walk into this node skip it. */
if (!visit_node_for_delete(root, wc, path->nodes[level],
wc->refs[level - 1], wc->flags[level - 1],
path->slots[level]))
goto skip;
/*
* We have to walk down into this node, and if we're currently at the
* DROP_REFERNCE stage and this block is shared then we need to switch
* to the UPDATE_BACKREF stage in order to convert to FULL_BACKREF.
*/
if (wc->stage == DROP_REFERENCE && wc->refs[level - 1] > 1) {
wc->stage = UPDATE_BACKREF;
wc->shared_level = level - 1;
}
ret = check_next_block_uptodate(trans, root, path, wc, next);
if (ret)
return ret;
level--;
ASSERT(level == btrfs_header_level(next));
if (level != btrfs_header_level(next)) {
btrfs_err(root->fs_info, "mismatched level");
ret = -EIO;
goto out_unlock;
}
path->nodes[level] = next;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK;
wc->level = level;
if (wc->level == 1)
wc->reada_slot = 0;
return 0;
skip:
ret = maybe_drop_reference(trans, root, path, wc, next, owner_root);
if (ret)
goto out_unlock;
wc->refs[level - 1] = 0;
wc->flags[level - 1] = 0;
wc->lookup_info = 1;
ret = 1;
out_unlock:
btrfs_tree_unlock(next);
free_extent_buffer(next);
return ret;
}
/*
* helper to process tree block while walking up the tree.
*
* when wc->stage == DROP_REFERENCE, this function drops
* reference count on the block.
*
* when wc->stage == UPDATE_BACKREF, this function changes
* wc->stage back to DROP_REFERENCE if we changed wc->stage
* to UPDATE_BACKREF previously while processing the block.
*
* NOTE: return value 1 means we should stop walking up.
*/
static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret = 0;
int level = wc->level;
struct extent_buffer *eb = path->nodes[level];
u64 parent = 0;
if (wc->stage == UPDATE_BACKREF) {
ASSERT(wc->shared_level >= level);
if (level < wc->shared_level)
goto out;
ret = find_next_key(path, level + 1, &wc->update_progress);
if (ret > 0)
wc->update_ref = 0;
wc->stage = DROP_REFERENCE;
wc->shared_level = -1;
path->slots[level] = 0;
/*
* check reference count again if the block isn't locked.
* we should start walking down the tree again if reference
* count is one.
*/
if (!path->locks[level]) {
ASSERT(level > 0);
btrfs_tree_lock(eb);
path->locks[level] = BTRFS_WRITE_LOCK;
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
&wc->refs[level],
&wc->flags[level],
NULL);
if (ret < 0) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return ret;
}
if (unlikely(wc->refs[level] == 0)) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
btrfs_err(fs_info, "bytenr %llu has 0 references, expect > 0",
eb->start);
return -EUCLEAN;
}
if (wc->refs[level] == 1) {
btrfs_tree_unlock_rw(eb, path->locks[level]);
path->locks[level] = 0;
return 1;
}
}
}
/* wc->stage == DROP_REFERENCE */
ASSERT(path->locks[level] || wc->refs[level] == 1);
if (wc->refs[level] == 1) {
if (level == 0) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
ret = btrfs_dec_ref(trans, root, eb, 1);
else
ret = btrfs_dec_ref(trans, root, eb, 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
if (is_fstree(btrfs_root_id(root))) {
ret = btrfs_qgroup_trace_leaf_items(trans, eb);
if (ret) {
btrfs_err_rl(fs_info,
"error %d accounting leaf items, quota is out of sync, rescan required",
ret);
}
}
}
/* Make block locked assertion in btrfs_clear_buffer_dirty happy. */
if (!path->locks[level]) {
btrfs_tree_lock(eb);
path->locks[level] = BTRFS_WRITE_LOCK;
}
btrfs_clear_buffer_dirty(trans, eb);
}
if (eb == root->node) {
if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = eb->start;
else if (btrfs_root_id(root) != btrfs_header_owner(eb))
goto owner_mismatch;
} else {
if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
parent = path->nodes[level + 1]->start;
else if (btrfs_root_id(root) !=
btrfs_header_owner(path->nodes[level + 1]))
goto owner_mismatch;
}
ret = btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent,
wc->refs[level] == 1);
if (ret < 0)
btrfs_abort_transaction(trans, ret);
out:
wc->refs[level] = 0;
wc->flags[level] = 0;
return ret;
owner_mismatch:
btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
btrfs_header_owner(eb), btrfs_root_id(root));
return -EUCLEAN;
}
/*
* walk_down_tree consists of two steps.
*
* walk_down_proc(). Look up the reference count and reference of our current
* wc->level. At this point path->nodes[wc->level] should be populated and
* uptodate, and in most cases should already be locked. If we are in
* DROP_REFERENCE and our refcount is > 1 then we've entered a shared node and
* we can walk back up the tree. If we are UPDATE_BACKREF we have to set
* FULL_BACKREF on this node if it's not already set, and then do the
* FULL_BACKREF conversion dance, which is to drop the root reference and add
* the shared reference to all of this nodes children.
*
* do_walk_down(). This is where we actually start iterating on the children of
* our current path->nodes[wc->level]. For DROP_REFERENCE that means dropping
* our reference to the children that return false from visit_node_for_delete(),
* which has various conditions where we know we can just drop our reference
* without visiting the node. For UPDATE_BACKREF we will skip any children that
* visit_node_for_delete() returns false for, only walking down when necessary.
* The bulk of the work for UPDATE_BACKREF occurs in the walk_up_tree() part of
* snapshot deletion.
*/
static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc)
{
int level = wc->level;
int ret = 0;
wc->lookup_info = 1;
while (level >= 0) {
ret = walk_down_proc(trans, root, path, wc);
if (ret)
break;
if (level == 0)
break;
if (path->slots[level] >=
btrfs_header_nritems(path->nodes[level]))
break;
ret = do_walk_down(trans, root, path, wc);
if (ret > 0) {
path->slots[level]++;
continue;
} else if (ret < 0)
break;
level = wc->level;
}
return (ret == 1) ? 0 : ret;
}
/*
* walk_up_tree() is responsible for making sure we visit every slot on our
* current node, and if we're at the end of that node then we call
* walk_up_proc() on our current node which will do one of a few things based on
* our stage.
*
* UPDATE_BACKREF. If we wc->level is currently less than our wc->shared_level
* then we need to walk back up the tree, and then going back down into the
* other slots via walk_down_tree to update any other children from our original
* wc->shared_level. Once we're at or above our wc->shared_level we can switch
* back to DROP_REFERENCE, lookup the current nodes refs and flags, and carry on.
*
* DROP_REFERENCE. If our refs == 1 then we're going to free this tree block.
* If we're level 0 then we need to btrfs_dec_ref() on all of the data extents
* in our current leaf. After that we call btrfs_free_tree_block() on the
* current node and walk up to the next node to walk down the next slot.
*/
static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
struct walk_control *wc, int max_level)
{
int level = wc->level;
int ret;
path->slots[level] = btrfs_header_nritems(path->nodes[level]);
while (level < max_level && path->nodes[level]) {
wc->level = level;
if (path->slots[level] + 1 <
btrfs_header_nritems(path->nodes[level])) {
path->slots[level]++;
return 0;
} else {
ret = walk_up_proc(trans, root, path, wc);
if (ret > 0)
return 0;
if (ret < 0)
return ret;
if (path->locks[level]) {
btrfs_tree_unlock_rw(path->nodes[level],
path->locks[level]);
path->locks[level] = 0;
}
free_extent_buffer(path->nodes[level]);
path->nodes[level] = NULL;
level++;
}
}
return 1;
}
/*
* drop a subvolume tree.
*
* this function traverses the tree freeing any blocks that only
* referenced by the tree.
*
* when a shared tree block is found. this function decreases its
* reference count by one. if update_ref is true, this function
* also make sure backrefs for the shared block and all lower level
* blocks are properly updated.
*
* If called with for_reloc == 0, may exit early with -EAGAIN
*/
int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
{
const bool is_reloc_root = (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID);
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct btrfs_trans_handle *trans;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root_item *root_item = &root->root_item;
struct walk_control *wc;
struct btrfs_key key;
const u64 rootid = btrfs_root_id(root);
int ret = 0;
int level;
bool root_dropped = false;
bool unfinished_drop = false;
btrfs_debug(fs_info, "Drop subvolume %llu", btrfs_root_id(root));
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
ret = -ENOMEM;
goto out;
}
/*
* Use join to avoid potential EINTR from transaction start. See
* wait_reserve_ticket and the whole reservation callchain.
*/
if (for_reloc)
trans = btrfs_join_transaction(tree_root);
else
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_free;
}
ret = btrfs_run_delayed_items(trans);
if (ret)
goto out_end_trans;
/*
* This will help us catch people modifying the fs tree while we're
* dropping it. It is unsafe to mess with the fs tree while it's being
* dropped as we unlock the root node and parent nodes as we walk down
* the tree, assuming nothing will change. If something does change
* then we'll have stale information and drop references to blocks we've
* already dropped.
*/
set_bit(BTRFS_ROOT_DELETING, &root->state);
unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
path->nodes[level] = btrfs_lock_root_node(root);
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK;
memset(&wc->update_progress, 0,
sizeof(wc->update_progress));
} else {
btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
memcpy(&wc->update_progress, &key,
sizeof(wc->update_progress));
level = btrfs_root_drop_level(root_item);
BUG_ON(level == 0);
path->lowest_level = level;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
path->lowest_level = 0;
if (ret < 0)
goto out_end_trans;
WARN_ON(ret > 0);
ret = 0;
/*
* unlock our path, this is safe because only this
* function is allowed to delete this snapshot
*/
btrfs_unlock_up_safe(path, 0);
level = btrfs_header_level(root->node);
while (1) {
btrfs_tree_lock(path->nodes[level]);
path->locks[level] = BTRFS_WRITE_LOCK;
/*
* btrfs_lookup_extent_info() returns 0 for success,
* or < 0 for error.
*/
ret = btrfs_lookup_extent_info(trans, fs_info,
path->nodes[level]->start,
level, 1, &wc->refs[level],
&wc->flags[level], NULL);
if (ret < 0)
goto out_end_trans;
BUG_ON(wc->refs[level] == 0);
if (level == btrfs_root_drop_level(root_item))
break;
btrfs_tree_unlock(path->nodes[level]);
path->locks[level] = 0;
WARN_ON(wc->refs[level] != 1);
level--;
}
}
wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = update_ref;
wc->keep_locks = 0;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
ret = walk_down_tree(trans, root, path, wc);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
break;
}
ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
break;
}
if (ret > 0) {
BUG_ON(wc->stage != DROP_REFERENCE);
ret = 0;
break;
}
if (wc->stage == DROP_REFERENCE) {
wc->drop_level = wc->level;
btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
&wc->drop_progress,
path->slots[wc->drop_level]);
}
btrfs_cpu_key_to_disk(&root_item->drop_progress,
&wc->drop_progress);
btrfs_set_root_drop_level(root_item, wc->drop_level);
BUG_ON(wc->level == 0);
if (btrfs_should_end_transaction(trans) ||
(!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
root_item);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_end_trans;
}
if (!is_reloc_root)
btrfs_set_last_root_drop_gen(fs_info, trans->transid);
btrfs_end_transaction_throttle(trans);
if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
btrfs_debug(fs_info,
"drop snapshot early exit");
ret = -EAGAIN;
goto out_free;
}
/*
* Use join to avoid potential EINTR from transaction
* start. See wait_reserve_ticket and the whole
* reservation callchain.
*/
if (for_reloc)
trans = btrfs_join_transaction(tree_root);
else
trans = btrfs_start_transaction(tree_root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_free;
}
}
}
btrfs_release_path(path);
if (ret)
goto out_end_trans;
ret = btrfs_del_root(trans, &root->root_key);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_end_trans;
}
if (!is_reloc_root) {
ret = btrfs_find_root(tree_root, &root->root_key, path,
NULL, NULL);
if (ret < 0) {
btrfs_abort_transaction(trans, ret);
goto out_end_trans;
} else if (ret > 0) {
ret = 0;
/*
* If we fail to delete the orphan item this time
* around, it'll get picked up the next time.
*
* The most common failure here is just -ENOENT.
*/
btrfs_del_orphan_item(trans, tree_root, btrfs_root_id(root));
}
}
/*
* This subvolume is going to be completely dropped, and won't be
* recorded as dirty roots, thus pertrans meta rsv will not be freed at
* commit transaction time. So free it here manually.
*/
btrfs_qgroup_convert_reserved_meta(root, INT_MAX);
btrfs_qgroup_free_meta_all_pertrans(root);
if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))
btrfs_add_dropped_root(trans, root);
else
btrfs_put_root(root);
root_dropped = true;
out_end_trans:
if (!is_reloc_root)
btrfs_set_last_root_drop_gen(fs_info, trans->transid);
btrfs_end_transaction_throttle(trans);
out_free:
kfree(wc);
btrfs_free_path(path);
out:
if (!ret && root_dropped) {
ret = btrfs_qgroup_cleanup_dropped_subvolume(fs_info, rootid);
if (ret < 0)
btrfs_warn_rl(fs_info,
"failed to cleanup qgroup 0/%llu: %d",
rootid, ret);
ret = 0;
}
/*
* We were an unfinished drop root, check to see if there are any
* pending, and if not clear and wake up any waiters.
*/
if (!ret && unfinished_drop)
btrfs_maybe_wake_unfinished_drop(fs_info);
/*
* So if we need to stop dropping the snapshot for whatever reason we
* need to make sure to add it back to the dead root list so that we
* keep trying to do the work later. This also cleans up roots if we
* don't have it in the radix (like when we recover after a power fail
* or unmount) so we don't leak memory.
*/
if (!for_reloc && !root_dropped)
btrfs_add_dead_root(root);
return ret;
}
/*
* drop subtree rooted at tree block 'node'.
*
* NOTE: this function will unlock and release tree block 'node'
* only used by relocation code
*/
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *node,
struct extent_buffer *parent)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_path *path;
struct walk_control *wc;
int level;
int parent_level;
int ret = 0;
BUG_ON(btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
wc = kzalloc(sizeof(*wc), GFP_NOFS);
if (!wc) {
btrfs_free_path(path);
return -ENOMEM;
}
btrfs_assert_tree_write_locked(parent);
parent_level = btrfs_header_level(parent);
atomic_inc(&parent->refs);
path->nodes[parent_level] = parent;
path->slots[parent_level] = btrfs_header_nritems(parent);
btrfs_assert_tree_write_locked(node);
level = btrfs_header_level(node);
path->nodes[level] = node;
path->slots[level] = 0;
path->locks[level] = BTRFS_WRITE_LOCK;
wc->refs[parent_level] = 1;
wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
wc->level = level;
wc->shared_level = -1;
wc->stage = DROP_REFERENCE;
wc->update_ref = 0;
wc->keep_locks = 1;
wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
while (1) {
ret = walk_down_tree(trans, root, path, wc);
if (ret < 0)
break;
ret = walk_up_tree(trans, root, path, wc, parent_level);
if (ret) {
if (ret > 0)
ret = 0;
break;
}
}
kfree(wc);
btrfs_free_path(path);
return ret;
}
/*
* Unpin the extent range in an error context and don't add the space back.
* Errors are not propagated further.
*/
void btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, u64 start, u64 end)
{
unpin_extent_range(fs_info, start, end, false);
}
/*
* It used to be that old block groups would be left around forever.
* Iterating over them would be enough to trim unused space. Since we
* now automatically remove them, we also need to iterate over unallocated
* space.
*
* We don't want a transaction for this since the discard may take a
* substantial amount of time. We don't require that a transaction be
* running, but we do need to take a running transaction into account
* to ensure that we're not discarding chunks that were released or
* allocated in the current transaction.
*
* Holding the chunks lock will prevent other threads from allocating
* or releasing chunks, but it won't prevent a running transaction
* from committing and releasing the memory that the pending chunks
* list head uses. For that, we need to take a reference to the
* transaction and hold the commit root sem. We only need to hold
* it while performing the free space search since we have already
* held back allocations.
*/
static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
{
u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0;
int ret;
*trimmed = 0;
/* Discard not supported = nothing to do. */
if (!bdev_max_discard_sectors(device->bdev))
return 0;
/* Not writable = nothing to do. */
if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
return 0;
/* No free space = nothing to do. */
if (device->total_bytes <= device->bytes_used)
return 0;
ret = 0;
while (1) {
struct btrfs_fs_info *fs_info = device->fs_info;
u64 bytes;
ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
if (ret)
break;
find_first_clear_extent_bit(&device->alloc_state, start,
&start, &end,
CHUNK_TRIMMED | CHUNK_ALLOCATED);
/* Check if there are any CHUNK_* bits left */
if (start > device->total_bytes) {
WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
btrfs_warn_in_rcu(fs_info,
"ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
start, end - start + 1,
btrfs_dev_name(device),
device->total_bytes);
mutex_unlock(&fs_info->chunk_mutex);
ret = 0;
break;
}
/* Ensure we skip the reserved space on each device. */
start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);
/*
* If find_first_clear_extent_bit find a range that spans the
* end of the device it will set end to -1, in this case it's up
* to the caller to trim the value to the size of the device.
*/
end = min(end, device->total_bytes - 1);
len = end - start + 1;
/* We didn't find any extents */
if (!len) {
mutex_unlock(&fs_info->chunk_mutex);
ret = 0;
break;
}
ret = btrfs_issue_discard(device->bdev, start, len,
&bytes);
if (!ret)
set_extent_bit(&device->alloc_state, start,
start + bytes - 1, CHUNK_TRIMMED, NULL);
mutex_unlock(&fs_info->chunk_mutex);
if (ret)
break;
start += len;
*trimmed += bytes;
if (fatal_signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
cond_resched();
}
return ret;
}
/*
* Trim the whole filesystem by:
* 1) trimming the free space in each block group
* 2) trimming the unallocated space on each device
*
* This will also continue trimming even if a block group or device encounters
* an error. The return value will be the last error, or 0 if nothing bad
* happens.
*/
int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
{
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
struct btrfs_block_group *cache = NULL;
struct btrfs_device *device;
u64 group_trimmed;
u64 range_end = U64_MAX;
u64 start;
u64 end;
u64 trimmed = 0;
u64 bg_failed = 0;
u64 dev_failed = 0;
int bg_ret = 0;
int dev_ret = 0;
int ret = 0;
if (range->start == U64_MAX)
return -EINVAL;
/*
* Check range overflow if range->len is set.
* The default range->len is U64_MAX.
*/
if (range->len != U64_MAX &&
check_add_overflow(range->start, range->len, &range_end))
return -EINVAL;
cache = btrfs_lookup_first_block_group(fs_info, range->start);
for (; cache; cache = btrfs_next_block_group(cache)) {
if (cache->start >= range_end) {
btrfs_put_block_group(cache);
break;
}
start = max(range->start, cache->start);
end = min(range_end, cache->start + cache->length);
if (end - start >= range->minlen) {
if (!btrfs_block_group_done(cache)) {
ret = btrfs_cache_block_group(cache, true);
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
ret = btrfs_trim_block_group(cache,
&group_trimmed,
start,
end,
range->minlen);
trimmed += group_trimmed;
if (ret) {
bg_failed++;
bg_ret = ret;
continue;
}
}
}
if (bg_failed)
btrfs_warn(fs_info,
"failed to trim %llu block group(s), last error %d",
bg_failed, bg_ret);
mutex_lock(&fs_devices->device_list_mutex);
list_for_each_entry(device, &fs_devices->devices, dev_list) {
if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
continue;
ret = btrfs_trim_free_extents(device, &group_trimmed);
trimmed += group_trimmed;
if (ret) {
dev_failed++;
dev_ret = ret;
break;
}
}
mutex_unlock(&fs_devices->device_list_mutex);
if (dev_failed)
btrfs_warn(fs_info,
"failed to trim %llu device(s), last error %d",
dev_failed, dev_ret);
range->len = trimmed;
if (bg_ret)
return bg_ret;
return dev_ret;
}
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