kernel-ark/drivers/md/dm-table.c
Alasdair G Kergon 55a62eef8d dm: rename request variables to bios
Use 'bio' in the name of variables and functions that deal with
bios rather than 'request' to avoid confusion with the normal
block layer use of 'request'.

No functional changes.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:47 +00:00

1672 lines
38 KiB
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);
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 */
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;
char dummy;
BUG_ON(!t);
if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 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_bios && tgt->discards_supported)
DMWARN("%s: %s: ignoring discards_supported because num_discard_bios 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);
char dummy;
if (!arg_str ||
(sscanf(arg_str, "%u%c", value, &dummy) != 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);
unsigned per_bio_data_size = 0;
struct dm_target *tgt;
unsigned i;
if (unlikely(type == DM_TYPE_NONE)) {
DMWARN("no table type is set, can't allocate mempools");
return -EINVAL;
}
if (type == DM_TYPE_BIO_BASED)
for (i = 0; i < t->num_targets; i++) {
tgt = t->targets + i;
per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
}
t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
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];
}
static int count_device(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
unsigned *num_devices = data;
(*num_devices)++;
return 0;
}
/*
* Check whether a table has no data devices attached using each
* target's iterate_devices method.
* Returns false if the result is unknown because a target doesn't
* support iterate_devices.
*/
bool dm_table_has_no_data_devices(struct dm_table *table)
{
struct dm_target *uninitialized_var(ti);
unsigned i = 0, num_devices = 0;
while (i < dm_table_get_num_targets(table)) {
ti = dm_table_get_target(table, i++);
if (!ti->type->iterate_devices)
return false;
ti->type->iterate_devices(ti, count_device, &num_devices);
if (num_devices)
return false;
}
return true;
}
/*
* 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_bios)
continue;
if (ti->flush_supported)
return 1;
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 int device_is_not_random(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_add_random(q);
}
static bool dm_table_all_devices_attribute(struct dm_table *t,
iterate_devices_callout_fn func)
{
struct dm_target *ti;
unsigned i = 0;
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, func, NULL))
return 0;
}
return 1;
}
static int device_not_write_same_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 && !q->limits.max_write_same_sectors;
}
static bool dm_table_supports_write_same(struct dm_table *t)
{
struct dm_target *ti;
unsigned i = 0;
while (i < dm_table_get_num_targets(t)) {
ti = dm_table_get_target(t, i++);
if (!ti->num_write_same_bios)
return false;
if (!ti->type->iterate_devices ||
!ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
return false;
}
return true;
}
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;
/* Ensure that all underlying devices are non-rotational. */
if (dm_table_all_devices_attribute(t, device_is_nonrot))
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
else
queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
if (!dm_table_supports_write_same(t))
q->limits.max_write_same_sectors = 0;
dm_table_set_integrity(t);
/*
* Determine whether or not this queue's I/O timings contribute
* to the entropy pool, Only request-based targets use this.
* Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
* have it set.
*/
if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
/*
* 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_bios)
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;
}