linux/fs/btrfs/delayed-ref.c
Nikolay Borisov 5e388e9581 btrfs: Fix race condition between delayed refs and blockgroup removal
When the delayed refs for a head are all run, eventually
cleanup_ref_head is called which (in case of deletion) obtains a
reference for the relevant btrfs_space_info struct by querying the bg
for the range. This is problematic because when the last extent of a
bg is deleted a race window emerges between removal of that bg and the
subsequent invocation of cleanup_ref_head. This can result in cache being null
and either a null pointer dereference or assertion failure.

	task: ffff8d04d31ed080 task.stack: ffff9e5dc10cc000
	RIP: 0010:assfail.constprop.78+0x18/0x1a [btrfs]
	RSP: 0018:ffff9e5dc10cfbe8 EFLAGS: 00010292
	RAX: 0000000000000044 RBX: 0000000000000000 RCX: 0000000000000000
	RDX: ffff8d04ffc1f868 RSI: ffff8d04ffc178c8 RDI: ffff8d04ffc178c8
	RBP: ffff8d04d29e5ea0 R08: 00000000000001f0 R09: 0000000000000001
	R10: ffff9e5dc0507d58 R11: 0000000000000001 R12: ffff8d04d29e5ea0
	R13: ffff8d04d29e5f08 R14: ffff8d04efe29b40 R15: ffff8d04efe203e0
	FS:  00007fbf58ead500(0000) GS:ffff8d04ffc00000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
	CR2: 00007fe6c6975648 CR3: 0000000013b2a000 CR4: 00000000000006f0
	DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
	Call Trace:
	 __btrfs_run_delayed_refs+0x10e7/0x12c0 [btrfs]
	 btrfs_run_delayed_refs+0x68/0x250 [btrfs]
	 btrfs_should_end_transaction+0x42/0x60 [btrfs]
	 btrfs_truncate_inode_items+0xaac/0xfc0 [btrfs]
	 btrfs_evict_inode+0x4c6/0x5c0 [btrfs]
	 evict+0xc6/0x190
	 do_unlinkat+0x19c/0x300
	 do_syscall_64+0x74/0x140
	 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
	RIP: 0033:0x7fbf589c57a7

To fix this, introduce a new flag "is_system" to head_ref structs,
which is populated at insertion time. This allows to decouple the
querying for the spaceinfo from querying the possibly deleted bg.

Fixes: d7eae3403f ("Btrfs: rework delayed ref total_bytes_pinned accounting")
CC: stable@vger.kernel.org # 4.14+
Suggested-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-20 19:17:25 +02:00

972 lines
26 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2009 Oracle. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include "ctree.h"
#include "delayed-ref.h"
#include "transaction.h"
#include "qgroup.h"
struct kmem_cache *btrfs_delayed_ref_head_cachep;
struct kmem_cache *btrfs_delayed_tree_ref_cachep;
struct kmem_cache *btrfs_delayed_data_ref_cachep;
struct kmem_cache *btrfs_delayed_extent_op_cachep;
/*
* delayed back reference update tracking. For subvolume trees
* we queue up extent allocations and backref maintenance for
* delayed processing. This avoids deep call chains where we
* add extents in the middle of btrfs_search_slot, and it allows
* us to buffer up frequently modified backrefs in an rb tree instead
* of hammering updates on the extent allocation tree.
*/
/*
* compare two delayed tree backrefs with same bytenr and type
*/
static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
struct btrfs_delayed_tree_ref *ref2)
{
if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
if (ref1->root < ref2->root)
return -1;
if (ref1->root > ref2->root)
return 1;
} else {
if (ref1->parent < ref2->parent)
return -1;
if (ref1->parent > ref2->parent)
return 1;
}
return 0;
}
/*
* compare two delayed data backrefs with same bytenr and type
*/
static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
struct btrfs_delayed_data_ref *ref2)
{
if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
if (ref1->root < ref2->root)
return -1;
if (ref1->root > ref2->root)
return 1;
if (ref1->objectid < ref2->objectid)
return -1;
if (ref1->objectid > ref2->objectid)
return 1;
if (ref1->offset < ref2->offset)
return -1;
if (ref1->offset > ref2->offset)
return 1;
} else {
if (ref1->parent < ref2->parent)
return -1;
if (ref1->parent > ref2->parent)
return 1;
}
return 0;
}
static int comp_refs(struct btrfs_delayed_ref_node *ref1,
struct btrfs_delayed_ref_node *ref2,
bool check_seq)
{
int ret = 0;
if (ref1->type < ref2->type)
return -1;
if (ref1->type > ref2->type)
return 1;
if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
btrfs_delayed_node_to_tree_ref(ref2));
else
ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
btrfs_delayed_node_to_data_ref(ref2));
if (ret)
return ret;
if (check_seq) {
if (ref1->seq < ref2->seq)
return -1;
if (ref1->seq > ref2->seq)
return 1;
}
return 0;
}
/* insert a new ref to head ref rbtree */
static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
struct rb_node *node)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent_node = NULL;
struct btrfs_delayed_ref_head *entry;
struct btrfs_delayed_ref_head *ins;
u64 bytenr;
ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
bytenr = ins->bytenr;
while (*p) {
parent_node = *p;
entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
href_node);
if (bytenr < entry->bytenr)
p = &(*p)->rb_left;
else if (bytenr > entry->bytenr)
p = &(*p)->rb_right;
else
return entry;
}
rb_link_node(node, parent_node, p);
rb_insert_color(node, root);
return NULL;
}
static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
struct btrfs_delayed_ref_node *ins)
{
struct rb_node **p = &root->rb_node;
struct rb_node *node = &ins->ref_node;
struct rb_node *parent_node = NULL;
struct btrfs_delayed_ref_node *entry;
while (*p) {
int comp;
parent_node = *p;
entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
ref_node);
comp = comp_refs(ins, entry, true);
if (comp < 0)
p = &(*p)->rb_left;
else if (comp > 0)
p = &(*p)->rb_right;
else
return entry;
}
rb_link_node(node, parent_node, p);
rb_insert_color(node, root);
return NULL;
}
/*
* find an head entry based on bytenr. This returns the delayed ref
* head if it was able to find one, or NULL if nothing was in that spot.
* If return_bigger is given, the next bigger entry is returned if no exact
* match is found.
*/
static struct btrfs_delayed_ref_head *
find_ref_head(struct rb_root *root, u64 bytenr,
int return_bigger)
{
struct rb_node *n;
struct btrfs_delayed_ref_head *entry;
n = root->rb_node;
entry = NULL;
while (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
if (bytenr < entry->bytenr)
n = n->rb_left;
else if (bytenr > entry->bytenr)
n = n->rb_right;
else
return entry;
}
if (entry && return_bigger) {
if (bytenr > entry->bytenr) {
n = rb_next(&entry->href_node);
if (!n)
n = rb_first(root);
entry = rb_entry(n, struct btrfs_delayed_ref_head,
href_node);
return entry;
}
return entry;
}
return NULL;
}
int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_ref_root *delayed_refs;
delayed_refs = &trans->transaction->delayed_refs;
lockdep_assert_held(&delayed_refs->lock);
if (mutex_trylock(&head->mutex))
return 0;
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
mutex_lock(&head->mutex);
spin_lock(&delayed_refs->lock);
if (RB_EMPTY_NODE(&head->href_node)) {
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
return -EAGAIN;
}
btrfs_put_delayed_ref_head(head);
return 0;
}
static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head,
struct btrfs_delayed_ref_node *ref)
{
lockdep_assert_held(&head->lock);
rb_erase(&ref->ref_node, &head->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
ref->in_tree = 0;
btrfs_put_delayed_ref(ref);
atomic_dec(&delayed_refs->num_entries);
if (trans->delayed_ref_updates)
trans->delayed_ref_updates--;
}
static bool merge_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head,
struct btrfs_delayed_ref_node *ref,
u64 seq)
{
struct btrfs_delayed_ref_node *next;
struct rb_node *node = rb_next(&ref->ref_node);
bool done = false;
while (!done && node) {
int mod;
next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
node = rb_next(node);
if (seq && next->seq >= seq)
break;
if (comp_refs(ref, next, false))
break;
if (ref->action == next->action) {
mod = next->ref_mod;
} else {
if (ref->ref_mod < next->ref_mod) {
swap(ref, next);
done = true;
}
mod = -next->ref_mod;
}
drop_delayed_ref(trans, delayed_refs, head, next);
ref->ref_mod += mod;
if (ref->ref_mod == 0) {
drop_delayed_ref(trans, delayed_refs, head, ref);
done = true;
} else {
/*
* Can't have multiples of the same ref on a tree block.
*/
WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
}
}
return done;
}
void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
struct btrfs_delayed_ref_node *ref;
struct rb_node *node;
u64 seq = 0;
lockdep_assert_held(&head->lock);
if (RB_EMPTY_ROOT(&head->ref_tree))
return;
/* We don't have too many refs to merge for data. */
if (head->is_data)
return;
spin_lock(&fs_info->tree_mod_seq_lock);
if (!list_empty(&fs_info->tree_mod_seq_list)) {
struct seq_list *elem;
elem = list_first_entry(&fs_info->tree_mod_seq_list,
struct seq_list, list);
seq = elem->seq;
}
spin_unlock(&fs_info->tree_mod_seq_lock);
again:
for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
if (seq && ref->seq >= seq)
continue;
if (merge_ref(trans, delayed_refs, head, ref, seq))
goto again;
}
}
int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
struct btrfs_delayed_ref_root *delayed_refs,
u64 seq)
{
struct seq_list *elem;
int ret = 0;
spin_lock(&fs_info->tree_mod_seq_lock);
if (!list_empty(&fs_info->tree_mod_seq_list)) {
elem = list_first_entry(&fs_info->tree_mod_seq_list,
struct seq_list, list);
if (seq >= elem->seq) {
btrfs_debug(fs_info,
"holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
(u32)(seq >> 32), (u32)seq,
(u32)(elem->seq >> 32), (u32)elem->seq,
delayed_refs);
ret = 1;
}
}
spin_unlock(&fs_info->tree_mod_seq_lock);
return ret;
}
struct btrfs_delayed_ref_head *
btrfs_select_ref_head(struct btrfs_trans_handle *trans)
{
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_delayed_ref_head *head;
u64 start;
bool loop = false;
delayed_refs = &trans->transaction->delayed_refs;
again:
start = delayed_refs->run_delayed_start;
head = find_ref_head(&delayed_refs->href_root, start, 1);
if (!head && !loop) {
delayed_refs->run_delayed_start = 0;
start = 0;
loop = true;
head = find_ref_head(&delayed_refs->href_root, start, 1);
if (!head)
return NULL;
} else if (!head && loop) {
return NULL;
}
while (head->processing) {
struct rb_node *node;
node = rb_next(&head->href_node);
if (!node) {
if (loop)
return NULL;
delayed_refs->run_delayed_start = 0;
start = 0;
loop = true;
goto again;
}
head = rb_entry(node, struct btrfs_delayed_ref_head,
href_node);
}
head->processing = 1;
WARN_ON(delayed_refs->num_heads_ready == 0);
delayed_refs->num_heads_ready--;
delayed_refs->run_delayed_start = head->bytenr +
head->num_bytes;
return head;
}
/*
* Helper to insert the ref_node to the tail or merge with tail.
*
* Return 0 for insert.
* Return >0 for merge.
*/
static int insert_delayed_ref(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_root *root,
struct btrfs_delayed_ref_head *href,
struct btrfs_delayed_ref_node *ref)
{
struct btrfs_delayed_ref_node *exist;
int mod;
int ret = 0;
spin_lock(&href->lock);
exist = tree_insert(&href->ref_tree, ref);
if (!exist)
goto inserted;
/* Now we are sure we can merge */
ret = 1;
if (exist->action == ref->action) {
mod = ref->ref_mod;
} else {
/* Need to change action */
if (exist->ref_mod < ref->ref_mod) {
exist->action = ref->action;
mod = -exist->ref_mod;
exist->ref_mod = ref->ref_mod;
if (ref->action == BTRFS_ADD_DELAYED_REF)
list_add_tail(&exist->add_list,
&href->ref_add_list);
else if (ref->action == BTRFS_DROP_DELAYED_REF) {
ASSERT(!list_empty(&exist->add_list));
list_del(&exist->add_list);
} else {
ASSERT(0);
}
} else
mod = -ref->ref_mod;
}
exist->ref_mod += mod;
/* remove existing tail if its ref_mod is zero */
if (exist->ref_mod == 0)
drop_delayed_ref(trans, root, href, exist);
spin_unlock(&href->lock);
return ret;
inserted:
if (ref->action == BTRFS_ADD_DELAYED_REF)
list_add_tail(&ref->add_list, &href->ref_add_list);
atomic_inc(&root->num_entries);
trans->delayed_ref_updates++;
spin_unlock(&href->lock);
return ret;
}
/*
* helper function to update the accounting in the head ref
* existing and update must have the same bytenr
*/
static noinline void
update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *existing,
struct btrfs_delayed_ref_head *update,
int *old_ref_mod_ret)
{
int old_ref_mod;
BUG_ON(existing->is_data != update->is_data);
spin_lock(&existing->lock);
if (update->must_insert_reserved) {
/* if the extent was freed and then
* reallocated before the delayed ref
* entries were processed, we can end up
* with an existing head ref without
* the must_insert_reserved flag set.
* Set it again here
*/
existing->must_insert_reserved = update->must_insert_reserved;
/*
* update the num_bytes so we make sure the accounting
* is done correctly
*/
existing->num_bytes = update->num_bytes;
}
if (update->extent_op) {
if (!existing->extent_op) {
existing->extent_op = update->extent_op;
} else {
if (update->extent_op->update_key) {
memcpy(&existing->extent_op->key,
&update->extent_op->key,
sizeof(update->extent_op->key));
existing->extent_op->update_key = true;
}
if (update->extent_op->update_flags) {
existing->extent_op->flags_to_set |=
update->extent_op->flags_to_set;
existing->extent_op->update_flags = true;
}
btrfs_free_delayed_extent_op(update->extent_op);
}
}
/*
* update the reference mod on the head to reflect this new operation,
* only need the lock for this case cause we could be processing it
* currently, for refs we just added we know we're a-ok.
*/
old_ref_mod = existing->total_ref_mod;
if (old_ref_mod_ret)
*old_ref_mod_ret = old_ref_mod;
existing->ref_mod += update->ref_mod;
existing->total_ref_mod += update->ref_mod;
/*
* If we are going to from a positive ref mod to a negative or vice
* versa we need to make sure to adjust pending_csums accordingly.
*/
if (existing->is_data) {
if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
delayed_refs->pending_csums -= existing->num_bytes;
if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
delayed_refs->pending_csums += existing->num_bytes;
}
spin_unlock(&existing->lock);
}
/*
* helper function to actually insert a head node into the rbtree.
* this does all the dirty work in terms of maintaining the correct
* overall modification count.
*/
static noinline struct btrfs_delayed_ref_head *
add_delayed_ref_head(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head_ref,
struct btrfs_qgroup_extent_record *qrecord,
u64 bytenr, u64 num_bytes, u64 ref_root, u64 reserved,
int action, int is_data, int is_system,
int *qrecord_inserted_ret,
int *old_ref_mod, int *new_ref_mod)
{
struct btrfs_delayed_ref_head *existing;
struct btrfs_delayed_ref_root *delayed_refs;
int count_mod = 1;
int must_insert_reserved = 0;
int qrecord_inserted = 0;
/* If reserved is provided, it must be a data extent. */
BUG_ON(!is_data && reserved);
/*
* the head node stores the sum of all the mods, so dropping a ref
* should drop the sum in the head node by one.
*/
if (action == BTRFS_UPDATE_DELAYED_HEAD)
count_mod = 0;
else if (action == BTRFS_DROP_DELAYED_REF)
count_mod = -1;
/*
* BTRFS_ADD_DELAYED_EXTENT means that we need to update
* the reserved accounting when the extent is finally added, or
* if a later modification deletes the delayed ref without ever
* inserting the extent into the extent allocation tree.
* ref->must_insert_reserved is the flag used to record
* that accounting mods are required.
*
* Once we record must_insert_reserved, switch the action to
* BTRFS_ADD_DELAYED_REF because other special casing is not required.
*/
if (action == BTRFS_ADD_DELAYED_EXTENT)
must_insert_reserved = 1;
else
must_insert_reserved = 0;
delayed_refs = &trans->transaction->delayed_refs;
refcount_set(&head_ref->refs, 1);
head_ref->bytenr = bytenr;
head_ref->num_bytes = num_bytes;
head_ref->ref_mod = count_mod;
head_ref->must_insert_reserved = must_insert_reserved;
head_ref->is_data = is_data;
head_ref->is_system = is_system;
head_ref->ref_tree = RB_ROOT;
INIT_LIST_HEAD(&head_ref->ref_add_list);
RB_CLEAR_NODE(&head_ref->href_node);
head_ref->processing = 0;
head_ref->total_ref_mod = count_mod;
head_ref->qgroup_reserved = 0;
head_ref->qgroup_ref_root = 0;
spin_lock_init(&head_ref->lock);
mutex_init(&head_ref->mutex);
/* Record qgroup extent info if provided */
if (qrecord) {
if (ref_root && reserved) {
head_ref->qgroup_ref_root = ref_root;
head_ref->qgroup_reserved = reserved;
}
qrecord->bytenr = bytenr;
qrecord->num_bytes = num_bytes;
qrecord->old_roots = NULL;
if(btrfs_qgroup_trace_extent_nolock(fs_info,
delayed_refs, qrecord))
kfree(qrecord);
else
qrecord_inserted = 1;
}
trace_add_delayed_ref_head(fs_info, head_ref, action);
existing = htree_insert(&delayed_refs->href_root,
&head_ref->href_node);
if (existing) {
WARN_ON(ref_root && reserved && existing->qgroup_ref_root
&& existing->qgroup_reserved);
update_existing_head_ref(delayed_refs, existing, head_ref,
old_ref_mod);
/*
* we've updated the existing ref, free the newly
* allocated ref
*/
kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
head_ref = existing;
} else {
if (old_ref_mod)
*old_ref_mod = 0;
if (is_data && count_mod < 0)
delayed_refs->pending_csums += num_bytes;
delayed_refs->num_heads++;
delayed_refs->num_heads_ready++;
atomic_inc(&delayed_refs->num_entries);
trans->delayed_ref_updates++;
}
if (qrecord_inserted_ret)
*qrecord_inserted_ret = qrecord_inserted;
if (new_ref_mod)
*new_ref_mod = head_ref->total_ref_mod;
return head_ref;
}
/*
* helper to insert a delayed tree ref into the rbtree.
*/
static noinline void
add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head_ref,
struct btrfs_delayed_ref_node *ref, u64 bytenr,
u64 num_bytes, u64 parent, u64 ref_root, int level,
int action)
{
struct btrfs_delayed_tree_ref *full_ref;
struct btrfs_delayed_ref_root *delayed_refs;
u64 seq = 0;
int ret;
if (action == BTRFS_ADD_DELAYED_EXTENT)
action = BTRFS_ADD_DELAYED_REF;
if (is_fstree(ref_root))
seq = atomic64_read(&fs_info->tree_mod_seq);
delayed_refs = &trans->transaction->delayed_refs;
/* first set the basic ref node struct up */
refcount_set(&ref->refs, 1);
ref->bytenr = bytenr;
ref->num_bytes = num_bytes;
ref->ref_mod = 1;
ref->action = action;
ref->is_head = 0;
ref->in_tree = 1;
ref->seq = seq;
RB_CLEAR_NODE(&ref->ref_node);
INIT_LIST_HEAD(&ref->add_list);
full_ref = btrfs_delayed_node_to_tree_ref(ref);
full_ref->parent = parent;
full_ref->root = ref_root;
if (parent)
ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
else
ref->type = BTRFS_TREE_BLOCK_REF_KEY;
full_ref->level = level;
trace_add_delayed_tree_ref(fs_info, ref, full_ref, action);
ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
/*
* XXX: memory should be freed at the same level allocated.
* But bad practice is anywhere... Follow it now. Need cleanup.
*/
if (ret > 0)
kmem_cache_free(btrfs_delayed_tree_ref_cachep, full_ref);
}
/*
* helper to insert a delayed data ref into the rbtree.
*/
static noinline void
add_delayed_data_ref(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head_ref,
struct btrfs_delayed_ref_node *ref, u64 bytenr,
u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
u64 offset, int action)
{
struct btrfs_delayed_data_ref *full_ref;
struct btrfs_delayed_ref_root *delayed_refs;
u64 seq = 0;
int ret;
if (action == BTRFS_ADD_DELAYED_EXTENT)
action = BTRFS_ADD_DELAYED_REF;
delayed_refs = &trans->transaction->delayed_refs;
if (is_fstree(ref_root))
seq = atomic64_read(&fs_info->tree_mod_seq);
/* first set the basic ref node struct up */
refcount_set(&ref->refs, 1);
ref->bytenr = bytenr;
ref->num_bytes = num_bytes;
ref->ref_mod = 1;
ref->action = action;
ref->is_head = 0;
ref->in_tree = 1;
ref->seq = seq;
RB_CLEAR_NODE(&ref->ref_node);
INIT_LIST_HEAD(&ref->add_list);
full_ref = btrfs_delayed_node_to_data_ref(ref);
full_ref->parent = parent;
full_ref->root = ref_root;
if (parent)
ref->type = BTRFS_SHARED_DATA_REF_KEY;
else
ref->type = BTRFS_EXTENT_DATA_REF_KEY;
full_ref->objectid = owner;
full_ref->offset = offset;
trace_add_delayed_data_ref(fs_info, ref, full_ref, action);
ret = insert_delayed_ref(trans, delayed_refs, head_ref, ref);
if (ret > 0)
kmem_cache_free(btrfs_delayed_data_ref_cachep, full_ref);
}
/*
* add a delayed tree ref. This does all of the accounting required
* to make sure the delayed ref is eventually processed before this
* transaction commits.
*/
int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, u64 parent,
u64 ref_root, int level, int action,
struct btrfs_delayed_extent_op *extent_op,
int *old_ref_mod, int *new_ref_mod)
{
struct btrfs_delayed_tree_ref *ref;
struct btrfs_delayed_ref_head *head_ref;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_qgroup_extent_record *record = NULL;
int qrecord_inserted;
int is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
BUG_ON(extent_op && extent_op->is_data);
ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
if (!ref)
return -ENOMEM;
head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
if (!head_ref)
goto free_ref;
if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
is_fstree(ref_root)) {
record = kmalloc(sizeof(*record), GFP_NOFS);
if (!record)
goto free_head_ref;
}
head_ref->extent_op = extent_op;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
/*
* insert both the head node and the new ref without dropping
* the spin lock
*/
head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
bytenr, num_bytes, 0, 0, action, 0,
is_system, &qrecord_inserted,
old_ref_mod, new_ref_mod);
add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
num_bytes, parent, ref_root, level, action);
spin_unlock(&delayed_refs->lock);
if (qrecord_inserted)
btrfs_qgroup_trace_extent_post(fs_info, record);
return 0;
free_head_ref:
kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
free_ref:
kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
return -ENOMEM;
}
/*
* add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
*/
int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
u64 parent, u64 ref_root,
u64 owner, u64 offset, u64 reserved, int action,
int *old_ref_mod, int *new_ref_mod)
{
struct btrfs_delayed_data_ref *ref;
struct btrfs_delayed_ref_head *head_ref;
struct btrfs_delayed_ref_root *delayed_refs;
struct btrfs_qgroup_extent_record *record = NULL;
int qrecord_inserted;
ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
if (!ref)
return -ENOMEM;
head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
if (!head_ref) {
kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
return -ENOMEM;
}
if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
is_fstree(ref_root)) {
record = kmalloc(sizeof(*record), GFP_NOFS);
if (!record) {
kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
kmem_cache_free(btrfs_delayed_ref_head_cachep,
head_ref);
return -ENOMEM;
}
}
head_ref->extent_op = NULL;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
/*
* insert both the head node and the new ref without dropping
* the spin lock
*/
head_ref = add_delayed_ref_head(fs_info, trans, head_ref, record,
bytenr, num_bytes, ref_root, reserved,
action, 1, 0, &qrecord_inserted,
old_ref_mod, new_ref_mod);
add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
num_bytes, parent, ref_root, owner, offset,
action);
spin_unlock(&delayed_refs->lock);
if (qrecord_inserted)
return btrfs_qgroup_trace_extent_post(fs_info, record);
return 0;
}
int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
struct btrfs_delayed_extent_op *extent_op)
{
struct btrfs_delayed_ref_head *head_ref;
struct btrfs_delayed_ref_root *delayed_refs;
head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
if (!head_ref)
return -ENOMEM;
head_ref->extent_op = extent_op;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
/*
* extent_ops just modify the flags of an extent and they don't result
* in ref count changes, hence it's safe to pass false/0 for is_system
* argument
*/
add_delayed_ref_head(fs_info, trans, head_ref, NULL, bytenr,
num_bytes, 0, 0, BTRFS_UPDATE_DELAYED_HEAD,
extent_op->is_data, 0, NULL, NULL, NULL);
spin_unlock(&delayed_refs->lock);
return 0;
}
/*
* this does a simple search for the head node for a given extent.
* It must be called with the delayed ref spinlock held, and it returns
* the head node if any where found, or NULL if not.
*/
struct btrfs_delayed_ref_head *
btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
{
return find_ref_head(&delayed_refs->href_root, bytenr, 0);
}
void __cold btrfs_delayed_ref_exit(void)
{
kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
}
int __init btrfs_delayed_ref_init(void)
{
btrfs_delayed_ref_head_cachep = kmem_cache_create(
"btrfs_delayed_ref_head",
sizeof(struct btrfs_delayed_ref_head), 0,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_delayed_ref_head_cachep)
goto fail;
btrfs_delayed_tree_ref_cachep = kmem_cache_create(
"btrfs_delayed_tree_ref",
sizeof(struct btrfs_delayed_tree_ref), 0,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_delayed_tree_ref_cachep)
goto fail;
btrfs_delayed_data_ref_cachep = kmem_cache_create(
"btrfs_delayed_data_ref",
sizeof(struct btrfs_delayed_data_ref), 0,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_delayed_data_ref_cachep)
goto fail;
btrfs_delayed_extent_op_cachep = kmem_cache_create(
"btrfs_delayed_extent_op",
sizeof(struct btrfs_delayed_extent_op), 0,
SLAB_MEM_SPREAD, NULL);
if (!btrfs_delayed_extent_op_cachep)
goto fail;
return 0;
fail:
btrfs_delayed_ref_exit();
return -ENOMEM;
}