- 根目录:
- drivers
- md
- dm-table.c
/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm.h"
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/namei.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#define DM_MSG_PREFIX "table"
#define MAX_DEPTH 16
#define NODE_SIZE L1_CACHE_BYTES
#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
/*
* The table has always exactly one reference from either mapped_device->map
* or hash_cell->new_map. This reference is not counted in table->holders.
* A pair of dm_create_table/dm_destroy_table functions is used for table
* creation/destruction.
*
* Temporary references from the other code increase table->holders. A pair
* of dm_table_get/dm_table_put functions is used to manipulate it.
*
* When the table is about to be destroyed, we wait for table->holders to
* drop to zero.
*/
struct dm_table {
struct mapped_device *md;
atomic_t holders;
unsigned type;
/* btree table */
unsigned int depth;
unsigned int counts[MAX_DEPTH]; /* in nodes */
sector_t *index[MAX_DEPTH];
unsigned int num_targets;
unsigned int num_allocated;
sector_t *highs;
struct dm_target *targets;
struct target_type *immutable_target_type;
unsigned integrity_supported:1;
unsigned singleton:1;
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
* and FMODE_WRITE.
*/
fmode_t mode;
/* a list of devices used by this table */
struct list_head devices;
/* events get handed up using this callback */
void (*event_fn)(void *);
void *event_context;
struct dm_md_mempools *mempools;
struct list_head target_callbacks;
};
/*
* Similar to ceiling(log_size(n))
*/
static unsigned int int_log(unsigned int n, unsigned int base)
{
int result = 0;
while (n > 1) {
n = dm_div_up(n, base);
result++;
}
return result;
}
/*
* Calculate the index of the child node of the n'th node k'th key.
*/
static inline unsigned int get_child(unsigned int n, unsigned int k)
{
return (n * CHILDREN_PER_NODE) + k;
}
/*
* Return the n'th node of level l from table t.
*/
static inline sector_t *get_node(struct dm_table *t,
unsigned int l, unsigned int n)
{
return t->index[l] + (n * KEYS_PER_NODE);
}
/*
* Return the highest key that you could lookup from the n'th
* node on level l of the btree.
*/
static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
{
for (; l < t->depth - 1; l++)
n = get_child(n, CHILDREN_PER_NODE - 1);
if (n >= t->counts[l])
return (sector_t) - 1;
return get_node(t, l, n)[KEYS_PER_NODE - 1];
}
/*
* Fills in a level of the btree based on the highs of the level
* below it.
*/
static int setup_btree_index(unsigned int l, struct dm_table *t)
{
unsigned int n, k;
sector_t *node;
for (n = 0U; n < t->counts[l]; n++) {
node = get_node(t, l, n);
for (k = 0U; k < KEYS_PER_NODE; k++)
node[k] = high(t, l + 1, get_child(n, k));
}
return 0;
}
void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
{
unsigned long size;
void *addr;
/*
* Check that we're not going to overflow.
*/
if (nmemb > (ULONG_MAX / elem_size))
return NULL;
size = nmemb * elem_size;
addr = vzalloc(size);
return addr;
}
EXPORT_SYMBOL(dm_vcalloc);
/*
* highs, and targets are managed as dynamic arrays during a
* table load.
*/
static int alloc_targets(struct dm_table *t, unsigned int num)
{
sector_t *n_highs;
struct dm_target *n_targets;
int n = t->num_targets;
/*
* Allocate both the target array and offset array at once.
* Append an empty entry to catch sectors beyond the end of
* the device.
*/
n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
sizeof(sector_t));
if (!n_highs)
return -ENOMEM;
n_targets = (struct dm_target *) (n_highs + num);
if (n) {
memcpy(n_highs, t->highs, sizeof(*n_highs) * n);
memcpy(n_targets, t->targets, sizeof(*n_targets) * n);
}
memset(n_highs + n, -1, sizeof(*n_highs) * (num - n));
vfree(t->highs);
t->num_allocated = num;
t->highs = n_highs;
t->targets = n_targets;
return 0;
}
int dm_table_create(struct dm_table **result, fmode_t mode,
unsigned num_targets, struct mapped_device *md)
{
struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
if (!t)
return -ENOMEM;
INIT_LIST_HEAD(&t->devices);
INIT_LIST_HEAD(&t->target_callbacks);
atomic_set(&t->holders, 0);
if (!num_targets)
num_targets = KEYS_PER_NODE;
num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
if (alloc_targets(t, num_targets)) {
kfree(t);
t = NULL;
return -ENOMEM;
}
t->mode = mode;
t->md = md;
*result = t;
return 0;
}
static void free_devices(struct list_head *devices)
{
struct list_head *tmp, *next;
list_for_each_safe(tmp, next, devices) {
struct dm_dev_internal *dd =
list_entry(tmp, struct dm_dev_internal, list);
DMWARN("dm_table_destroy: dm_put_device call missing for %s",
dd->dm_dev.name);
kfree(dd);
}
}
void dm_table_destroy(struct dm_table *t)
{
unsigned int i;
if (!t)
return;
while (atomic_read(&t->holders))
msleep(1);
smp_mb();
/* free the indexes */
if (t->depth >= 2)
vfree(t->index[t->depth - 2]);
/* free the targets */
for (i = 0; i < t->num_targets; i++) {
struct dm_target *tgt = t->targets + i;
if (tgt->type->dtr)
tgt->type->dtr(tgt);
dm_put_target_type(tgt->type);
}
vfree(t->highs);
/* free the device list */
if (t->devices.next != &t->devices)
free_devices(&t->devices);
dm_free_md_mempools(t->mempools);
kfree(t);
}
void dm_table_get(struct dm_table *t)
{
atomic_inc(&t->holders);
}
EXPORT_SYMBOL(dm_table_get);
void dm_table_put(struct dm_table *t)
{
if (!t)
return;
smp_mb__before_atomic_dec();
atomic_dec(&t->holders);
}
EXPORT_SYMBOL(dm_table_put);
/*
* Checks to see if we need to extend highs or targets.
*/
static inline int check_space(struct dm_table *t)
{
if (t->num_targets >= t->num_allocated)
return alloc_targets(t, t->num_allocated * 2);
return 0;
}
/*
* See if we've already got a device in the list.
*/
static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
{
struct dm_dev_internal *dd;
list_for_each_entry (dd, l, list)
if (dd->dm_dev.bdev->bd_dev == dev)
return dd;
return NULL;
}
/*
* Open a device so we can use it as a map destination.
*/
static int open_dev(struct dm_dev_internal *d, dev_t dev,
struct mapped_device *md)
{
static char *_claim_ptr = "I belong to device-mapper";
struct block_device *bdev;
int r;
BUG_ON(d->dm_dev.bdev);
bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
r = bd_link_disk_holder(bdev, dm_disk(md));
if (r) {
blkdev_put(bdev, d->dm_dev.mode | FMODE_EXCL);
return r;
}
d->dm_dev.bdev = bdev;
return 0;
}
/*
* Close a device that we've been using.
*/
static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
{
if (!d->dm_dev.bdev)
return;
bd_unlink_disk_holder(d->dm_dev.bdev, dm_disk(md));
blkdev_put(d->dm_dev.bdev, d->dm_dev.mode | FMODE_EXCL);
d->dm_dev.bdev = NULL;
}
/*
* If possible, this checks an area of a destination device is invalid.
*/
static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct request_queue *q;
struct queue_limits *limits = data;
struct block_device *bdev = dev->bdev;
sector_t dev_size =
i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
unsigned short logical_block_size_sectors =
limits->logical_block_size >> SECTOR_SHIFT;
char b[BDEVNAME_SIZE];
/*
* Some devices exist without request functions,
* such as loop devices not yet bound to backing files.
* Forbid the use of such devices.
*/
q = bdev_get_queue(bdev);
if (!q || !q->make_request_fn) {
DMWARN("%s: %s is not yet initialised: "
"start=%llu, len=%llu, dev_size=%llu",
dm_device_name(ti->table->md), bdevname(bdev, b),
(unsigned long long)start,
(unsigned long long)len,
(unsigned long long)dev_size);
return 1;
}
if (!dev_size)
return 0;
if ((start >= dev_size) || (start + len > dev_size)) {
DMWARN("%s: %s too small for target: "
"start=%llu, len=%llu, dev_size=%llu",
dm_device_name(ti->table->md), bdevname(bdev, b),
(unsigned long long)start,
(unsigned long long)len,
(unsigned long long)dev_size);
return 1;
}
if (logical_block_size_sectors <= 1)
return 0;
if (start & (logical_block_size_sectors - 1)) {
DMWARN("%s: start=%llu not aligned to h/w "
"logical block size %u of %s",
dm_device_name(ti->table->md),
(unsigned long long)start,
limits->logical_block_size, bdevname(bdev, b));
return 1;
}
if (len & (logical_block_size_sectors - 1)) {
DMWARN("%s: len=%llu not aligned to h/w "
"logical block size %u of %s",
dm_device_name(ti->table->md),
(unsigned long long)len,
limits->logical_block_size, bdevname(bdev, b));
return 1;
}
return 0;
}
/*
* This upgrades the mode on an already open dm_dev, being
* careful to leave things as they were if we fail to reopen the
* device and not to touch the existing bdev field in case
* it is accessed concurrently inside dm_table_any_congested().
*/
static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
struct mapped_device *md)
{
int r;
struct dm_dev_internal dd_new, dd_old;
dd_new = dd_old = *dd;
dd_new.dm_dev.mode |= new_mode;
dd_new.dm_dev.bdev = NULL;
r = open_dev(&dd_new, dd->dm_dev.bdev->bd_dev, md);
if (r)
return r;
dd->dm_dev.mode |= new_mode;
close_dev(&dd_old, md);
return 0;
}
/*
* Add a device to the list, or just increment the usage count if
* it's already present.
*/
int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
struct dm_dev **result)
{
int r;
dev_t uninitialized_var(dev);
struct dm_dev_internal *dd;
unsigned int major, minor;
struct dm_table *t = ti->table;
BUG_ON(!t);
if (sscanf(path, "%u:%u", &major, &minor) == 2) {
/* Extract the major/minor numbers */
dev = MKDEV(major, minor);
if (MAJOR(dev) != major || MINOR(dev) != minor)
return -EOVERFLOW;
} else {
/* convert the path to a device */
struct block_device *bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
dev = bdev->bd_dev;
bdput(bdev);
}
dd = find_device(&t->devices, dev);
if (!dd) {
dd = kmalloc(sizeof(*dd), GFP_KERNEL);
if (!dd)
return -ENOMEM;
dd->dm_dev.mode = mode;
dd->dm_dev.bdev = NULL;
if ((r = open_dev(dd, dev, t->md))) {
kfree(dd);
return r;
}
format_dev_t(dd->dm_dev.name, dev);
atomic_set(&dd->count, 0);
list_add(&dd->list, &t->devices);
} else if (dd->dm_dev.mode != (mode | dd->dm_dev.mode)) {
r = upgrade_mode(dd, mode, t->md);
if (r)
return r;
}
atomic_inc(&dd->count);
*result = &dd->dm_dev;
return 0;
}
EXPORT_SYMBOL(dm_get_device);
int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct queue_limits *limits = data;
struct block_device *bdev = dev->bdev;
struct request_queue *q = bdev_get_queue(bdev);
char b[BDEVNAME_SIZE];
if (unlikely(!q)) {
DMWARN("%s: Cannot set limits for nonexistent device %s",
dm_device_name(ti->table->md), bdevname(bdev, b));
return 0;
}
if (bdev_stack_limits(limits, bdev, start) < 0)
DMWARN("%s: adding target device %s caused an alignment inconsistency: "
"physical_block_size=%u, logical_block_size=%u, "
"alignment_offset=%u, start=%llu",
dm_device_name(ti->table->md), bdevname(bdev, b),
q->limits.physical_block_size,
q->limits.logical_block_size,
q->limits.alignment_offset,
(unsigned long long) start << SECTOR_SHIFT);
/*
* Check if merge fn is supported.
* If not we'll force DM to use PAGE_SIZE or
* smaller I/O, just to be safe.
*/
if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
blk_limits_max_hw_sectors(limits,
(unsigned int) (PAGE_SIZE >> 9));
return 0;
}
EXPORT_SYMBOL_GPL(dm_set_device_limits);
/*
* Decrement a device's use count and remove it if necessary.
*/
void dm_put_device(struct dm_target *ti, struct dm_dev *d)
{
struct dm_dev_internal *dd = container_of(d, struct dm_dev_internal,
dm_dev);
if (atomic_dec_and_test(&dd->count)) {
close_dev(dd, ti->table->md);
list_del(&dd->list);
kfree(dd);
}
}
EXPORT_SYMBOL(dm_put_device);
/*
* Checks to see if the target joins onto the end of the table.
*/
static int adjoin(struct dm_table *table, struct dm_target *ti)
{
struct dm_target *prev;
if (!table->num_targets)
return !ti->begin;
prev = &table->targets[table->num_targets - 1];
return (ti->begin == (prev->begin + prev->len));
}
/*
* Used to dynamically allocate the arg array.
*/
static char **realloc_argv(unsigned *array_size, char **old_argv)
{
char **argv;
unsigned new_size;
new_size = *array_size ? *array_size * 2 : 64;
argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL);
if (argv) {
memcpy(argv, old_argv, *array_size * sizeof(*argv));
*array_size = new_size;
}
kfree(old_argv);
return argv;
}
/*
* Destructively splits up the argument list to pass to ctr.
*/
int dm_split_args(int *argc, char ***argvp, char *input)
{
char *start, *end = input, *out, **argv = NULL;
unsigned array_size = 0;
*argc = 0;
if (!input) {
*argvp = NULL;
return 0;
}
argv = realloc_argv(&array_size, argv);
if (!argv)
return -ENOMEM;
while (1) {
/* Skip whitespace */
start = skip_spaces(end);
if (!*start)
break; /* success, we hit the end */
/* 'out' is used to remove any back-quotes */
end = out = start;
while (*end) {
/* Everything apart from '\0' can be quoted */
if (*end == '\\' && *(end + 1)) {
*out++ = *(end + 1);
end += 2;
continue;
}
if (isspace(*end))
break; /* end of token */
*out++ = *end++;
}
/* have we already filled the array ? */
if ((*argc + 1) > array_size) {
argv = realloc_argv(&array_size, argv);
if (!argv)
return -ENOMEM;
}
/* we know this is whitespace */
if (*end)
end++;
/* terminate the string and put it in the array */
*out = '\0';
argv[*argc] = start;
(*argc)++;
}
*argvp = argv;
return 0;
}
/*
* Impose necessary and sufficient conditions on a devices's table such
* that any incoming bio which respects its logical_block_size can be
* processed successfully. If it falls across the boundary between
* two or more targets, the size of each piece it gets split into must
* be compatible with the logical_block_size of the target processing it.
*/
static int validate_hardware_logical_block_alignment(struct dm_table *table,
struct queue_limits *limits)
{
/*
* This function uses arithmetic modulo the logical_block_size
* (in units of 512-byte sectors).
*/
unsigned short device_logical_block_size_sects =
limits->logical_block_size >> SECTOR_SHIFT;
/*
* Offset of the start of the next table entry, mod logical_block_size.
*/
unsigned short next_target_start = 0;
/*
* Given an aligned bio that extends beyond the end of a
* target, how many sectors must the next target handle?
*/
unsigned short remaining = 0;
struct dm_target *uninitialized_var(ti);
struct queue_limits ti_limits;
unsigned i = 0;
/*
* Check each entry in the table in turn.
*/
while (i < dm_table_get_num_targets(table)) {
ti = dm_table_get_target(table, i++);
blk_set_stacking_limits(&ti_limits);
/* combine all target devices' limits */
if (ti->type->iterate_devices)
ti->type->iterate_devices(ti, dm_set_device_limits,
&ti_limits);
/*
* If the remaining sectors fall entirely within this
* table entry are they compatible with its logical_block_size?
*/
if (remaining < ti->len &&
remaining & ((ti_limits.logical_block_size >>
SECTOR_SHIFT) - 1))
break; /* Error */
next_target_start =
(unsigned short) ((next_target_start + ti->len) &
(device_logical_block_size_sects - 1));
remaining = next_target_start ?
device_logical_block_size_sects - next_target_start : 0;
}
if (remaining) {
DMWARN("%s: table line %u (start sect %llu len %llu) "
"not aligned to h/w logical block size %u",
dm_device_name(table->md), i,
(unsigned long long) ti->begin,
(unsigned long long) ti->len,
limits->logical_block_size);
return -EINVAL;
}
return 0;
}
int dm_table_add_target(struct dm_table *t, const char *type,
sector_t start, sector_t len, char *params)
{
int r = -EINVAL, argc;
char **argv;
struct dm_target *tgt;
if (t->singleton) {
DMERR("%s: target type %s must appear alone in table",
dm_device_name(t->md), t->targets->type->name);
return -EINVAL;
}
if ((r = check_space(t)))
return r;
tgt = t->targets + t->num_targets;
memset(tgt, 0, sizeof(*tgt));
if (!len) {
DMERR("%s: zero-length target", dm_device_name(t->md));
return -EINVAL;
}
tgt->type = dm_get_target_type(type);
if (!tgt->type) {
DMERR("%s: %s: unknown target type", dm_device_name(t->md),
type);
return -EINVAL;
}
if (dm_target_needs_singleton(tgt->type)) {
if (t->num_targets) {
DMERR("%s: target type %s must appear alone in table",
dm_device_name(t->md), type);
return -EINVAL;
}
t->singleton = 1;
}
if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
DMERR("%s: target type %s may not be included in read-only tables",
dm_device_name(t->md), type);
return -EINVAL;
}
if (t->immutable_target_type) {
if (t->immutable_target_type != tgt->type) {
DMERR("%s: immutable target type %s cannot be mixed with other target types",
dm_device_name(t->md), t->immutable_target_type->name);
return -EINVAL;
}
} else if (dm_target_is_immutable(tgt->type)) {
if (t->num_targets) {
DMERR("%s: immutable target type %s cannot be mixed with other target types",
dm_device_name(t->md), tgt->type->name);
return -EINVAL;
}
t->immutable_target_type = tgt->type;
}
tgt->table = t;
tgt->begin = start;
tgt->len = len;
tgt->error = "Unknown error";
/*
* Does this target adjoin the previous one ?
*/
if (!adjoin(t, tgt)) {
tgt->error = "Gap in table";
r = -EINVAL;
goto bad;
}
r = dm_split_args(&argc, &argv, params);
if (r) {
tgt->error = "couldn't split parameters (insufficient memory)";
goto bad;
}
r = tgt->type->ctr(tgt, argc, argv);
kfree(argv);
if (r)
goto bad;
t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
if (!tgt->num_discard_requests && tgt->discards_supported)
DMWARN("%s: %s: ignoring discards_supported because num_discard_requests is zero.",
dm_device_name(t->md), type);
return 0;
bad:
DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
dm_put_target_type(tgt->type);
return r;
}
/*
* Target argument parsing helpers.
*/
static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *value, char **error, unsigned grouped)
{
const char *arg_str = dm_shift_arg(arg_set);
if (!arg_str ||
(sscanf(arg_str, "%u", value) != 1) ||
(*value < arg->min) ||
(*value > arg->max) ||
(grouped && arg_set->argc < *value)) {
*error = arg->error;
return -EINVAL;
}
return 0;
}
int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *value, char **error)
{
return validate_next_arg(arg, arg_set, value, error, 0);
}
EXPORT_SYMBOL(dm_read_arg);
int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
unsigned *value, char **error)
{
return validate_next_arg(arg, arg_set, value, error, 1);
}
EXPORT_SYMBOL(dm_read_arg_group);
const char *dm_shift_arg(struct dm_arg_set *as)
{
char *r;
if (as->argc) {
as->argc--;
r = *as->argv;
as->argv++;
return r;
}
return NULL;
}
EXPORT_SYMBOL(dm_shift_arg);
void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
{
BUG_ON(as->argc < num_args);
as->argc -= num_args;
as->argv += num_args;
}
EXPORT_SYMBOL(dm_consume_args);
static int dm_table_set_type(struct dm_table *t)
{
unsigned i;
unsigned bio_based = 0, request_based = 0;
struct dm_target *tgt;
struct dm_dev_internal *dd;
struct list_head *devices;
for (i = 0; i < t->num_targets; i++) {
tgt = t->targets + i;
if (dm_target_request_based(tgt))
request_based = 1;
else
bio_based = 1;
if (bio_based && request_based) {
DMWARN("Inconsistent table: different target types"
" can't be mixed up");
return -EINVAL;
}
}
if (bio_based) {
/* We must use this table as bio-based */
t->type = DM_TYPE_BIO_BASED;
return 0;
}
BUG_ON(!request_based); /* No targets in this table */
/* Non-request-stackable devices can't be used for request-based dm */
devices = dm_table_get_devices(t);
list_for_each_entry(dd, devices, list) {
if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev.bdev))) {
DMWARN("table load rejected: including"
" non-request-stackable devices");
return -EINVAL;
}
}
/*
* Request-based dm supports only tables that have a single target now.
* To support multiple targets, request splitting support is needed,
* and that needs lots of changes in the block-layer.
* (e.g. request completion process for partial completion.)
*/
if (t->num_targets > 1) {
DMWARN("Request-based dm doesn't support multiple targets yet");
return -EINVAL;
}
t->type = DM_TYPE_REQUEST_BASED;
return 0;
}
unsigned dm_table_get_type(struct dm_table *t)
{
return t->type;
}
struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
{
return t->immutable_target_type;
}
bool dm_table_request_based(struct dm_table *t)
{
return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
}
int dm_table_alloc_md_mempools(struct dm_table *t)
{
unsigned type = dm_table_get_type(t);
if (unlikely(type == DM_TYPE_NONE)) {
DMWARN("no table type is set, can't allocate mempools");
return -EINVAL;
}
t->mempools = dm_alloc_md_mempools(type, t->integrity_supported);
if (!t->mempools)
return -ENOMEM;
return 0;
}
void dm_table_free_md_mempools(struct dm_table *t)
{
dm_free_md_mempools(t->mempools);
t->mempools = NULL;
}
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
{
return t->mempools;
}
static int setup_indexes(struct dm_table *t)
{
int i;
unsigned int total = 0;
sector_t *indexes;
/* allocate the space for *all* the indexes */
for (i = t->depth - 2; i >= 0; i--) {
t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
total += t->counts[i];
}
indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
if (!indexes)
return -ENOMEM;
/* set up internal nodes, bottom-up */
for (i = t->depth - 2; i >= 0; i--) {
t->index[i] = indexes;
indexes += (KEYS_PER_NODE * t->counts[i]);
setup_btree_index(i, t);
}
return 0;
}
/*
* Builds the btree to index the map.
*/
static int dm_table_build_index(struct dm_table *t)
{
int r = 0;
unsigned int leaf_nodes;
/* how many indexes will the btree have ? */
leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
/* leaf layer has already been set up */
t->counts[t->depth - 1] = leaf_nodes;
t->index[t->depth - 1] = t->highs;
if (t->depth >= 2)
r = setup_indexes(t);
return r;
}
/*
* Get a disk whose integrity profile reflects the table's profile.
* If %match_all is true, all devices' profiles must match.
* If %match_all is false, all devices must at least have an
* allocated integrity profile; but uninitialized is ok.
* Returns NULL if integrity support was inconsistent or unavailable.
*/
static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
bool match_all)
{
struct list_head *devices = dm_table_get_devices(t);
struct dm_dev_internal *dd = NULL;
struct gendisk *prev_disk = NULL, *template_disk = NULL;
list_for_each_entry(dd, devices, list) {
template_disk = dd->dm_dev.bdev->bd_disk;
if (!blk_get_integrity(template_disk))
goto no_integrity;
if (!match_all && !blk_integrity_is_initialized(template_disk))
continue; /* skip uninitialized profiles */
else if (prev_disk &&
blk_integrity_compare(prev_disk, template_disk) < 0)
goto no_integrity;
prev_disk = template_disk;
}
return template_disk;
no_integrity:
if (prev_disk)
DMWARN("%s: integrity not set: %s and %s profile mismatch",
dm_device_name(t->md),
prev_disk->disk_name,
template_disk->disk_name);
return NULL;
}
/*
* Register the mapped device for blk_integrity support if
* the underlying devices have an integrity profile. But all devices
* may not have matching profiles (checking all devices isn't reliable
* during table load because this table may use other DM device(s) which
* must be resumed before they will have an initialized integity profile).
* Stacked DM devices force a 2 stage integrity profile validation:
* 1 - during load, validate all initialized integrity profiles match
* 2 - during resume, validate all integrity profiles match
*/
static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
{
struct gendisk *template_disk = NULL;
template_disk = dm_table_get_integrity_disk(t, false);
if (!template_disk)
return 0;
if (!blk_integrity_is_initialized(dm_disk(md))) {
t->integrity_supported = 1;
return blk_integrity_register(dm_disk(md), NULL);
}
/*
* If DM device already has an initalized integrity
* profile the new profile should not conflict.
*/
if (blk_integrity_is_initialized(template_disk) &&
blk_integrity_compare(dm_disk(md), template_disk) < 0) {
DMWARN("%s: conflict with existing integrity profile: "
"%s profile mismatch",
dm_device_name(t->md),
template_disk->disk_name);
return 1;
}
/* Preserve existing initialized integrity profile */
t->integrity_supported = 1;
return 0;
}
/*
* Prepares the table for use by building the indices,
* setting the type, and allocating mempools.
*/
int dm_table_complete(struct dm_table *t)
{
int r;
r = dm_table_set_type(t);
if (r) {
DMERR("unable to set table type");
return r;
}
r = dm_table_build_index(t);
if (r) {
DMERR("unable to build btrees");
return r;
}
r = dm_table_prealloc_integrity(t, t->md);
if (r) {
DMERR("could not register integrity profile.");
return r;
}
r = dm_table_alloc_md_mempools(t);
if (r)
DMERR("unable to allocate mempools");
return r;
}
static DEFINE_MUTEX(_event_lock);
void dm_table_event_callback(struct dm_table *t,
void (*fn)(void *), void *context)
{
mutex_lock(&_event_lock);
t->event_fn = fn;
t->event_context = context;
mutex_unlock(&_event_lock);
}
void dm_table_event(struct dm_table *t)
{
/*
* You can no longer call dm_table_event() from interrupt
* context, use a bottom half instead.
*/
BUG_ON(in_interrupt());
mutex_lock(&_event_lock);
if (t->event_fn)
t->event_fn(t->event_context);
mutex_unlock(&_event_lock);
}
EXPORT_SYMBOL(dm_table_event);
sector_t dm_table_get_size(struct dm_table *t)
{
return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
}
EXPORT_SYMBOL(dm_table_get_size);
struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
{
if (index >= t->num_targets)
return NULL;
return t->targets + index;
}
/*
* Search the btree for the correct target.
*
* Caller should check returned pointer with dm_target_is_valid()
* to trap I/O beyond end of device.
*/
struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
{
unsigned int l, n = 0, k = 0;
sector_t *node;
for (l = 0; l < t->depth; l++) {
n = get_child(n, k);
node = get_node(t, l, n);
for (k = 0; k < KEYS_PER_NODE; k++)
if (node[k] >= sector)
break;
}
return &t->targets[(KEYS_PER_NODE * n) + k];
}
/*
* Establish the new table's queue_limits and validate them.
*/
int dm_calculate_queue_limits(struct dm_table *table,
struct queue_limits *limits)
{
struct dm_target *uninitialized_var(ti);
struct queue_limits ti_limits;
unsigned i = 0;
blk_set_stacking_limits(limits);
while (i < dm_table_get_num_targets(table)) {
blk_set_stacking_limits(&ti_limits);
ti = dm_table_get_target(table, i++);
if (!ti->type->iterate_devices)
goto combine_limits;
/*
* Combine queue limits of all the devices this target uses.
*/
ti->type->iterate_devices(ti, dm_set_device_limits,
&ti_limits);
/* Set I/O hints portion of queue limits */
if (ti->type->io_hints)
ti->type->io_hints(ti, &ti_limits);
/*
* Check each device area is consistent with the target's
* overall queue limits.
*/
if (ti->type->iterate_devices(ti, device_area_is_invalid,
&ti_limits))
return -EINVAL;
combine_limits:
/*
* Merge this target's queue limits into the overall limits
* for the table.
*/
if (blk_stack_limits(limits, &ti_limits, 0) < 0)
DMWARN("%s: adding target device "
"(start sect %llu len %llu) "
"caused an alignment inconsistency",
dm_device_name(table->md),
(unsigned long long) ti->begin,
(unsigned long long) ti->len);
}
return validate_hardware_logical_block_alignment(table, limits);
}
/*
* Set the integrity profile for this device if all devices used have
* matching profiles. We're quite deep in the resume path but still
* don't know if all devices (particularly DM devices this device
* may be stacked on) have matching profiles. Even if the profiles
* don't match we have no way to fail (to resume) at this point.
*/
static void dm_table_set_integrity(struct dm_table *t)
{
struct gendisk *template_disk = NULL;
if (!blk_get_integrity(dm_disk(t->md)))
return;
template_disk = dm_table_get_integrity_disk(t, true);
if (template_disk)
blk_integrity_register(dm_disk(t->md),
blk_get_integrity(template_disk));
else if (blk_integrity_is_initialized(dm_disk(t->md)))
DMWARN("%s: device no longer has a valid integrity profile",
dm_device_name(t->md));
else
DMWARN("%s: unable to establish an integrity profile",
dm_device_name(t->md));
}
static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
unsigned flush = (*(unsigned *)data);
struct request_queue *q = bdev_get_queue(dev->bdev);
return q && (q->flush_flags & flush);
}
static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
{
struct dm_target *ti;
unsigned i = 0;
/*
* Require at least one underlying device to support flushes.
* t->devices includes internal dm devices such as mirror logs
* so we need to use iterate_devices here, which targets
* supporting flushes must provide.
*/
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (!ti->num_flush_requests)
continue;
if (ti->type->iterate_devices &&
ti->type->iterate_devices(ti, device_flush_capable, &flush))
return 1;
}
return 0;
}
static bool dm_table_discard_zeroes_data(struct dm_table *t)
{
struct dm_target *ti;
unsigned i = 0;
/* Ensure that all targets supports discard_zeroes_data. */
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (ti->discard_zeroes_data_unsupported)
return 0;
}
return 1;
}
static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct request_queue *q = bdev_get_queue(dev->bdev);
return q && blk_queue_nonrot(q);
}
static bool dm_table_is_nonrot(struct dm_table *t)
{
struct dm_target *ti;
unsigned i = 0;
/* Ensure that all underlying device are non-rotational. */
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (!ti->type->iterate_devices ||
!ti->type->iterate_devices(ti, device_is_nonrot, NULL))
return 0;
}
return 1;
}
void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
struct queue_limits *limits)
{
unsigned flush = 0;
/*
* Copy table's limits to the DM device's request_queue
*/
q->limits = *limits;
if (!dm_table_supports_discards(t))
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
else
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
if (dm_table_supports_flush(t, REQ_FLUSH)) {
flush |= REQ_FLUSH;
if (dm_table_supports_flush(t, REQ_FUA))
flush |= REQ_FUA;
}
blk_queue_flush(q, flush);
if (!dm_table_discard_zeroes_data(t))
q->limits.discard_zeroes_data = 0;
if (dm_table_is_nonrot(t))
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
else
queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
dm_table_set_integrity(t);
/*
* QUEUE_FLAG_STACKABLE must be set after all queue settings are
* visible to other CPUs because, once the flag is set, incoming bios
* are processed by request-based dm, which refers to the queue
* settings.
* Until the flag set, bios are passed to bio-based dm and queued to
* md->deferred where queue settings are not needed yet.
* Those bios are passed to request-based dm at the resume time.
*/
smp_mb();
if (dm_table_request_based(t))
queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
}
unsigned int dm_table_get_num_targets(struct dm_table *t)
{
return t->num_targets;
}
struct list_head *dm_table_get_devices(struct dm_table *t)
{
return &t->devices;
}
fmode_t dm_table_get_mode(struct dm_table *t)
{
return t->mode;
}
EXPORT_SYMBOL(dm_table_get_mode);
static void suspend_targets(struct dm_table *t, unsigned postsuspend)
{
int i = t->num_targets;
struct dm_target *ti = t->targets;
while (i--) {
if (postsuspend) {
if (ti->type->postsuspend)
ti->type->postsuspend(ti);
} else if (ti->type->presuspend)
ti->type->presuspend(ti);
ti++;
}
}
void dm_table_presuspend_targets(struct dm_table *t)
{
if (!t)
return;
suspend_targets(t, 0);
}
void dm_table_postsuspend_targets(struct dm_table *t)
{
if (!t)
return;
suspend_targets(t, 1);
}
int dm_table_resume_targets(struct dm_table *t)
{
int i, r = 0;
for (i = 0; i < t->num_targets; i++) {
struct dm_target *ti = t->targets + i;
if (!ti->type->preresume)
continue;
r = ti->type->preresume(ti);
if (r)
return r;
}
for (i = 0; i < t->num_targets; i++) {
struct dm_target *ti = t->targets + i;
if (ti->type->resume)
ti->type->resume(ti);
}
return 0;
}
void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
{
list_add(&cb->list, &t->target_callbacks);
}
EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
int dm_table_any_congested(struct dm_table *t, int bdi_bits)
{
struct dm_dev_internal *dd;
struct list_head *devices = dm_table_get_devices(t);
struct dm_target_callbacks *cb;
int r = 0;
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
char b[BDEVNAME_SIZE];
if (likely(q))
r |= bdi_congested(&q->backing_dev_info, bdi_bits);
else
DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
dm_device_name(t->md),
bdevname(dd->dm_dev.bdev, b));
}
list_for_each_entry(cb, &t->target_callbacks, list)
if (cb->congested_fn)
r |= cb->congested_fn(cb, bdi_bits);
return r;
}
int dm_table_any_busy_target(struct dm_table *t)
{
unsigned i;
struct dm_target *ti;
for (i = 0; i < t->num_targets; i++) {
ti = t->targets + i;
if (ti->type->busy && ti->type->busy(ti))
return 1;
}
return 0;
}
struct mapped_device *dm_table_get_md(struct dm_table *t)
{
return t->md;
}
EXPORT_SYMBOL(dm_table_get_md);
static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct request_queue *q = bdev_get_queue(dev->bdev);
return q && blk_queue_discard(q);
}
bool dm_table_supports_discards(struct dm_table *t)
{
struct dm_target *ti;
unsigned i = 0;
/*
* Unless any target used by the table set discards_supported,
* require at least one underlying device to support discards.
* t->devices includes internal dm devices such as mirror logs
* so we need to use iterate_devices here, which targets
* supporting discard selectively must provide.
*/
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (!ti->num_discard_requests)
continue;
if (ti->discards_supported)
return 1;
if (ti->type->iterate_devices &&
ti->type->iterate_devices(ti, device_discard_capable, NULL))
return 1;
}
return 0;
}