diff options
Diffstat (limited to 'drivers/md/dm-table.c')
| -rw-r--r-- | drivers/md/dm-table.c | 1577 |
1 files changed, 1577 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c new file mode 100644 index 00000000..2e227fbf --- /dev/null +++ b/drivers/md/dm-table.c @@ -0,0 +1,1577 @@ +/* + * 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 */ + 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_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); + 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); + + 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; +} |