mirror of
https://github.com/torvalds/linux.git
synced 2024-12-25 12:21:37 +00:00
4feaef830d
The space-maps track the reference counts for disk blocks allocated by both the thin-provisioning and cache targets. There are variants for tracking metadata blocks and data blocks. Transactionality is implemented by never touching blocks from the previous transaction, so we can rollback in the event of a crash. When allocating a new block we need to ensure the block is free (has reference count of 0) in both the current and previous transaction. Prior to this fix we were doing this by searching for a free block in the previous transaction, and relying on a 'begin' counter to track where the last allocation in the current transaction was. This 'begin' field was not being updated in all code paths (eg, increment of a data block reference count due to breaking sharing of a neighbour block in the same btree leaf). This fix keeps the 'begin' field, but now it's just a hint to speed up the search. Instead the current transaction is searched for a free block, and then the old transaction is double checked to ensure it's free. Much simpler. This fixes reports of sm_disk_new_block()'s BUG_ON() triggering when DM thin-provisioning's snapshots are heavily used. Reported-by: Eric Wheeler <dm-devel@lists.ewheeler.net> Cc: stable@vger.kernel.org Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
321 lines
6.6 KiB
C
321 lines
6.6 KiB
C
/*
|
|
* Copyright (C) 2011 Red Hat, Inc.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include "dm-space-map-common.h"
|
|
#include "dm-space-map-disk.h"
|
|
#include "dm-space-map.h"
|
|
#include "dm-transaction-manager.h"
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/export.h>
|
|
#include <linux/device-mapper.h>
|
|
|
|
#define DM_MSG_PREFIX "space map disk"
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
/*
|
|
* Space map interface.
|
|
*/
|
|
struct sm_disk {
|
|
struct dm_space_map sm;
|
|
|
|
struct ll_disk ll;
|
|
struct ll_disk old_ll;
|
|
|
|
dm_block_t begin;
|
|
dm_block_t nr_allocated_this_transaction;
|
|
};
|
|
|
|
static void sm_disk_destroy(struct dm_space_map *sm)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
kfree(smd);
|
|
}
|
|
|
|
static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
return sm_ll_extend(&smd->ll, extra_blocks);
|
|
}
|
|
|
|
static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
*count = smd->old_ll.nr_blocks;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
*count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
|
|
uint32_t *result)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
return sm_ll_lookup(&smd->ll, b, result);
|
|
}
|
|
|
|
static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
|
|
int *result)
|
|
{
|
|
int r;
|
|
uint32_t count;
|
|
|
|
r = sm_disk_get_count(sm, b, &count);
|
|
if (r)
|
|
return r;
|
|
|
|
*result = count > 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
|
|
uint32_t count)
|
|
{
|
|
int r;
|
|
uint32_t old_count;
|
|
enum allocation_event ev;
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
r = sm_ll_insert(&smd->ll, b, count, &ev);
|
|
if (!r) {
|
|
switch (ev) {
|
|
case SM_NONE:
|
|
break;
|
|
|
|
case SM_ALLOC:
|
|
/*
|
|
* This _must_ be free in the prior transaction
|
|
* otherwise we've lost atomicity.
|
|
*/
|
|
smd->nr_allocated_this_transaction++;
|
|
break;
|
|
|
|
case SM_FREE:
|
|
/*
|
|
* It's only free if it's also free in the last
|
|
* transaction.
|
|
*/
|
|
r = sm_ll_lookup(&smd->old_ll, b, &old_count);
|
|
if (r)
|
|
return r;
|
|
|
|
if (!old_count)
|
|
smd->nr_allocated_this_transaction--;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
|
|
{
|
|
int r;
|
|
enum allocation_event ev;
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
r = sm_ll_inc(&smd->ll, b, &ev);
|
|
if (!r && (ev == SM_ALLOC))
|
|
/*
|
|
* This _must_ be free in the prior transaction
|
|
* otherwise we've lost atomicity.
|
|
*/
|
|
smd->nr_allocated_this_transaction++;
|
|
|
|
return r;
|
|
}
|
|
|
|
static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
|
|
{
|
|
int r;
|
|
uint32_t old_count;
|
|
enum allocation_event ev;
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
r = sm_ll_dec(&smd->ll, b, &ev);
|
|
if (!r && (ev == SM_FREE)) {
|
|
/*
|
|
* It's only free if it's also free in the last
|
|
* transaction.
|
|
*/
|
|
r = sm_ll_lookup(&smd->old_ll, b, &old_count);
|
|
if (!r && !old_count)
|
|
smd->nr_allocated_this_transaction--;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
|
|
{
|
|
int r;
|
|
enum allocation_event ev;
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
/*
|
|
* Any block we allocate has to be free in both the old and current ll.
|
|
*/
|
|
r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
|
|
if (r)
|
|
return r;
|
|
|
|
smd->begin = *b + 1;
|
|
r = sm_ll_inc(&smd->ll, *b, &ev);
|
|
if (!r) {
|
|
BUG_ON(ev != SM_ALLOC);
|
|
smd->nr_allocated_this_transaction++;
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int sm_disk_commit(struct dm_space_map *sm)
|
|
{
|
|
int r;
|
|
dm_block_t nr_free;
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
|
|
r = sm_disk_get_nr_free(sm, &nr_free);
|
|
if (r)
|
|
return r;
|
|
|
|
r = sm_ll_commit(&smd->ll);
|
|
if (r)
|
|
return r;
|
|
|
|
memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
|
|
smd->begin = 0;
|
|
smd->nr_allocated_this_transaction = 0;
|
|
|
|
r = sm_disk_get_nr_free(sm, &nr_free);
|
|
if (r)
|
|
return r;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
|
|
{
|
|
*result = sizeof(struct disk_sm_root);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
|
|
{
|
|
struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
|
|
struct disk_sm_root root_le;
|
|
|
|
root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
|
|
root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
|
|
root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
|
|
root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
|
|
|
|
if (max < sizeof(root_le))
|
|
return -ENOSPC;
|
|
|
|
memcpy(where_le, &root_le, sizeof(root_le));
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*----------------------------------------------------------------*/
|
|
|
|
static struct dm_space_map ops = {
|
|
.destroy = sm_disk_destroy,
|
|
.extend = sm_disk_extend,
|
|
.get_nr_blocks = sm_disk_get_nr_blocks,
|
|
.get_nr_free = sm_disk_get_nr_free,
|
|
.get_count = sm_disk_get_count,
|
|
.count_is_more_than_one = sm_disk_count_is_more_than_one,
|
|
.set_count = sm_disk_set_count,
|
|
.inc_block = sm_disk_inc_block,
|
|
.dec_block = sm_disk_dec_block,
|
|
.new_block = sm_disk_new_block,
|
|
.commit = sm_disk_commit,
|
|
.root_size = sm_disk_root_size,
|
|
.copy_root = sm_disk_copy_root,
|
|
.register_threshold_callback = NULL
|
|
};
|
|
|
|
struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
|
|
dm_block_t nr_blocks)
|
|
{
|
|
int r;
|
|
struct sm_disk *smd;
|
|
|
|
smd = kmalloc(sizeof(*smd), GFP_KERNEL);
|
|
if (!smd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
smd->begin = 0;
|
|
smd->nr_allocated_this_transaction = 0;
|
|
memcpy(&smd->sm, &ops, sizeof(smd->sm));
|
|
|
|
r = sm_ll_new_disk(&smd->ll, tm);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = sm_ll_extend(&smd->ll, nr_blocks);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = sm_disk_commit(&smd->sm);
|
|
if (r)
|
|
goto bad;
|
|
|
|
return &smd->sm;
|
|
|
|
bad:
|
|
kfree(smd);
|
|
return ERR_PTR(r);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_sm_disk_create);
|
|
|
|
struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
|
|
void *root_le, size_t len)
|
|
{
|
|
int r;
|
|
struct sm_disk *smd;
|
|
|
|
smd = kmalloc(sizeof(*smd), GFP_KERNEL);
|
|
if (!smd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
smd->begin = 0;
|
|
smd->nr_allocated_this_transaction = 0;
|
|
memcpy(&smd->sm, &ops, sizeof(smd->sm));
|
|
|
|
r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = sm_disk_commit(&smd->sm);
|
|
if (r)
|
|
goto bad;
|
|
|
|
return &smd->sm;
|
|
|
|
bad:
|
|
kfree(smd);
|
|
return ERR_PTR(r);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_sm_disk_open);
|
|
|
|
/*----------------------------------------------------------------*/
|