diff options
Diffstat (limited to 'drivers/md/persistent-data')
21 files changed, 5625 insertions, 0 deletions
diff --git a/drivers/md/persistent-data/Kconfig b/drivers/md/persistent-data/Kconfig new file mode 100644 index 00000000000..ceb359050a5 --- /dev/null +++ b/drivers/md/persistent-data/Kconfig @@ -0,0 +1,8 @@ +config DM_PERSISTENT_DATA + tristate + depends on BLK_DEV_DM && EXPERIMENTAL + select LIBCRC32C + select DM_BUFIO + ---help--- + Library providing immutable on-disk data structure support for + device-mapper targets such as the thin provisioning target. diff --git a/drivers/md/persistent-data/Makefile b/drivers/md/persistent-data/Makefile new file mode 100644 index 00000000000..cfa95f66223 --- /dev/null +++ b/drivers/md/persistent-data/Makefile @@ -0,0 +1,11 @@ +obj-$(CONFIG_DM_PERSISTENT_DATA) += dm-persistent-data.o +dm-persistent-data-objs := \ + dm-block-manager.o \ + dm-space-map-checker.o \ + dm-space-map-common.o \ + dm-space-map-disk.o \ + dm-space-map-metadata.o \ + dm-transaction-manager.o \ + dm-btree.o \ + dm-btree-remove.o \ + dm-btree-spine.o diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c new file mode 100644 index 00000000000..0317ecdc6e5 --- /dev/null +++ b/drivers/md/persistent-data/dm-block-manager.c @@ -0,0 +1,620 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#include "dm-block-manager.h" +#include "dm-persistent-data-internal.h" +#include "../dm-bufio.h" + +#include <linux/crc32c.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/rwsem.h> +#include <linux/device-mapper.h> +#include <linux/stacktrace.h> + +#define DM_MSG_PREFIX "block manager" + +/*----------------------------------------------------------------*/ + +/* + * This is a read/write semaphore with a couple of differences. + * + * i) There is a restriction on the number of concurrent read locks that + * may be held at once. This is just an implementation detail. + * + * ii) Recursive locking attempts are detected and return EINVAL. A stack + * trace is also emitted for the previous lock aquisition. + * + * iii) Priority is given to write locks. + */ +#define MAX_HOLDERS 4 +#define MAX_STACK 10 + +typedef unsigned long stack_entries[MAX_STACK]; + +struct block_lock { + spinlock_t lock; + __s32 count; + struct list_head waiters; + struct task_struct *holders[MAX_HOLDERS]; + +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + struct stack_trace traces[MAX_HOLDERS]; + stack_entries entries[MAX_HOLDERS]; +#endif +}; + +struct waiter { + struct list_head list; + struct task_struct *task; + int wants_write; +}; + +static unsigned __find_holder(struct block_lock *lock, + struct task_struct *task) +{ + unsigned i; + + for (i = 0; i < MAX_HOLDERS; i++) + if (lock->holders[i] == task) + break; + + BUG_ON(i == MAX_HOLDERS); + return i; +} + +/* call this *after* you increment lock->count */ +static void __add_holder(struct block_lock *lock, struct task_struct *task) +{ + unsigned h = __find_holder(lock, NULL); +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + struct stack_trace *t; +#endif + + get_task_struct(task); + lock->holders[h] = task; + +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + t = lock->traces + h; + t->nr_entries = 0; + t->max_entries = MAX_STACK; + t->entries = lock->entries[h]; + t->skip = 2; + save_stack_trace(t); +#endif +} + +/* call this *before* you decrement lock->count */ +static void __del_holder(struct block_lock *lock, struct task_struct *task) +{ + unsigned h = __find_holder(lock, task); + lock->holders[h] = NULL; + put_task_struct(task); +} + +static int __check_holder(struct block_lock *lock) +{ + unsigned i; +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + static struct stack_trace t; + static stack_entries entries; +#endif + + for (i = 0; i < MAX_HOLDERS; i++) { + if (lock->holders[i] == current) { + DMERR("recursive lock detected in pool metadata"); +#ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING + DMERR("previously held here:"); + print_stack_trace(lock->traces + i, 4); + + DMERR("subsequent aquisition attempted here:"); + t.nr_entries = 0; + t.max_entries = MAX_STACK; + t.entries = entries; + t.skip = 3; + save_stack_trace(&t); + print_stack_trace(&t, 4); +#endif + return -EINVAL; + } + } + + return 0; +} + +static void __wait(struct waiter *w) +{ + for (;;) { + set_task_state(current, TASK_UNINTERRUPTIBLE); + + if (!w->task) + break; + + schedule(); + } + + set_task_state(current, TASK_RUNNING); +} + +static void __wake_waiter(struct waiter *w) +{ + struct task_struct *task; + + list_del(&w->list); + task = w->task; + smp_mb(); + w->task = NULL; + wake_up_process(task); +} + +/* + * We either wake a few readers or a single writer. + */ +static void __wake_many(struct block_lock *lock) +{ + struct waiter *w, *tmp; + + BUG_ON(lock->count < 0); + list_for_each_entry_safe(w, tmp, &lock->waiters, list) { + if (lock->count >= MAX_HOLDERS) + return; + + if (w->wants_write) { + if (lock->count > 0) + return; /* still read locked */ + + lock->count = -1; + __add_holder(lock, w->task); + __wake_waiter(w); + return; + } + + lock->count++; + __add_holder(lock, w->task); + __wake_waiter(w); + } +} + +static void bl_init(struct block_lock *lock) +{ + int i; + + spin_lock_init(&lock->lock); + lock->count = 0; + INIT_LIST_HEAD(&lock->waiters); + for (i = 0; i < MAX_HOLDERS; i++) + lock->holders[i] = NULL; +} + +static int __available_for_read(struct block_lock *lock) +{ + return lock->count >= 0 && + lock->count < MAX_HOLDERS && + list_empty(&lock->waiters); +} + +static int bl_down_read(struct block_lock *lock) +{ + int r; + struct waiter w; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) { + spin_unlock(&lock->lock); + return r; + } + + if (__available_for_read(lock)) { + lock->count++; + __add_holder(lock, current); + spin_unlock(&lock->lock); + return 0; + } + + get_task_struct(current); + + w.task = current; + w.wants_write = 0; + list_add_tail(&w.list, &lock->waiters); + spin_unlock(&lock->lock); + + __wait(&w); + put_task_struct(current); + return 0; +} + +static int bl_down_read_nonblock(struct block_lock *lock) +{ + int r; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) + goto out; + + if (__available_for_read(lock)) { + lock->count++; + __add_holder(lock, current); + r = 0; + } else + r = -EWOULDBLOCK; + +out: + spin_unlock(&lock->lock); + return r; +} + +static void bl_up_read(struct block_lock *lock) +{ + spin_lock(&lock->lock); + BUG_ON(lock->count <= 0); + __del_holder(lock, current); + --lock->count; + if (!list_empty(&lock->waiters)) + __wake_many(lock); + spin_unlock(&lock->lock); +} + +static int bl_down_write(struct block_lock *lock) +{ + int r; + struct waiter w; + + spin_lock(&lock->lock); + r = __check_holder(lock); + if (r) { + spin_unlock(&lock->lock); + return r; + } + + if (lock->count == 0 && list_empty(&lock->waiters)) { + lock->count = -1; + __add_holder(lock, current); + spin_unlock(&lock->lock); + return 0; + } + + get_task_struct(current); + w.task = current; + w.wants_write = 1; + + /* + * Writers given priority. We know there's only one mutator in the + * system, so ignoring the ordering reversal. + */ + list_add(&w.list, &lock->waiters); + spin_unlock(&lock->lock); + + __wait(&w); + put_task_struct(current); + + return 0; +} + +static void bl_up_write(struct block_lock *lock) +{ + spin_lock(&lock->lock); + __del_holder(lock, current); + lock->count = 0; + if (!list_empty(&lock->waiters)) + __wake_many(lock); + spin_unlock(&lock->lock); +} + +static void report_recursive_bug(dm_block_t b, int r) +{ + if (r == -EINVAL) + DMERR("recursive acquisition of block %llu requested.", + (unsigned long long) b); +} + +/*----------------------------------------------------------------*/ + +/* + * Block manager is currently implemented using dm-bufio. struct + * dm_block_manager and struct dm_block map directly onto a couple of + * structs in the bufio interface. I want to retain the freedom to move + * away from bufio in the future. So these structs are just cast within + * this .c file, rather than making it through to the public interface. + */ +static struct dm_buffer *to_buffer(struct dm_block *b) +{ + return (struct dm_buffer *) b; +} + +static struct dm_bufio_client *to_bufio(struct dm_block_manager *bm) +{ + return (struct dm_bufio_client *) bm; +} + +dm_block_t dm_block_location(struct dm_block *b) +{ + return dm_bufio_get_block_number(to_buffer(b)); +} +EXPORT_SYMBOL_GPL(dm_block_location); + +void *dm_block_data(struct dm_block *b) +{ + return dm_bufio_get_block_data(to_buffer(b)); +} +EXPORT_SYMBOL_GPL(dm_block_data); + +struct buffer_aux { + struct dm_block_validator *validator; + struct block_lock lock; + int write_locked; +}; + +static void dm_block_manager_alloc_callback(struct dm_buffer *buf) +{ + struct buffer_aux *aux = dm_bufio_get_aux_data(buf); + aux->validator = NULL; + bl_init(&aux->lock); +} + +static void dm_block_manager_write_callback(struct dm_buffer *buf) +{ + struct buffer_aux *aux = dm_bufio_get_aux_data(buf); + if (aux->validator) { + aux->validator->prepare_for_write(aux->validator, (struct dm_block *) buf, + dm_bufio_get_block_size(dm_bufio_get_client(buf))); + } +} + +/*---------------------------------------------------------------- + * Public interface + *--------------------------------------------------------------*/ +struct dm_block_manager *dm_block_manager_create(struct block_device *bdev, + unsigned block_size, + unsigned cache_size, + unsigned max_held_per_thread) +{ + return (struct dm_block_manager *) + dm_bufio_client_create(bdev, block_size, max_held_per_thread, + sizeof(struct buffer_aux), + dm_block_manager_alloc_callback, + dm_block_manager_write_callback); +} +EXPORT_SYMBOL_GPL(dm_block_manager_create); + +void dm_block_manager_destroy(struct dm_block_manager *bm) +{ + return dm_bufio_client_destroy(to_bufio(bm)); +} +EXPORT_SYMBOL_GPL(dm_block_manager_destroy); + +unsigned dm_bm_block_size(struct dm_block_manager *bm) +{ + return dm_bufio_get_block_size(to_bufio(bm)); +} +EXPORT_SYMBOL_GPL(dm_bm_block_size); + +dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm) +{ + return dm_bufio_get_device_size(to_bufio(bm)); +} + +static int dm_bm_validate_buffer(struct dm_block_manager *bm, + struct dm_buffer *buf, + struct buffer_aux *aux, + struct dm_block_validator *v) +{ + if (unlikely(!aux->validator)) { + int r; + if (!v) + return 0; + r = v->check(v, (struct dm_block *) buf, dm_bufio_get_block_size(to_bufio(bm))); + if (unlikely(r)) + return r; + aux->validator = v; + } else { + if (unlikely(aux->validator != v)) { + DMERR("validator mismatch (old=%s vs new=%s) for block %llu", + aux->validator->name, v ? v->name : "NULL", + (unsigned long long) + dm_bufio_get_block_number(buf)); + return -EINVAL; + } + } + + return 0; +} +int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_read(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_read(&aux->lock); + if (unlikely(r)) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + + aux->write_locked = 0; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_read(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_read_lock); + +int dm_bm_write_lock(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_read(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_write(&aux->lock); + if (r) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + + aux->write_locked = 1; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_write(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_write_lock); + +int dm_bm_read_try_lock(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + struct buffer_aux *aux; + void *p; + int r; + + p = dm_bufio_get(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + if (unlikely(!p)) + return -EWOULDBLOCK; + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_read_nonblock(&aux->lock); + if (r < 0) { + dm_bufio_release(to_buffer(*result)); + report_recursive_bug(b, r); + return r; + } + aux->write_locked = 0; + + r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v); + if (unlikely(r)) { + bl_up_read(&aux->lock); + dm_bufio_release(to_buffer(*result)); + return r; + } + + return 0; +} + +int dm_bm_write_lock_zero(struct dm_block_manager *bm, + dm_block_t b, struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + struct buffer_aux *aux; + void *p; + + p = dm_bufio_new(to_bufio(bm), b, (struct dm_buffer **) result); + if (unlikely(IS_ERR(p))) + return PTR_ERR(p); + + memset(p, 0, dm_bm_block_size(bm)); + + aux = dm_bufio_get_aux_data(to_buffer(*result)); + r = bl_down_write(&aux->lock); + if (r) { + dm_bufio_release(to_buffer(*result)); + return r; + } + + aux->write_locked = 1; + aux->validator = v; + + return 0; +} + +int dm_bm_unlock(struct dm_block *b) +{ + struct buffer_aux *aux; + aux = dm_bufio_get_aux_data(to_buffer(b)); + + if (aux->write_locked) { + dm_bufio_mark_buffer_dirty(to_buffer(b)); + bl_up_write(&aux->lock); + } else + bl_up_read(&aux->lock); + + dm_bufio_release(to_buffer(b)); + + return 0; +} +EXPORT_SYMBOL_GPL(dm_bm_unlock); + +int dm_bm_unlock_move(struct dm_block *b, dm_block_t n) +{ + struct buffer_aux *aux; + + aux = dm_bufio_get_aux_data(to_buffer(b)); + + if (aux->write_locked) { + dm_bufio_mark_buffer_dirty(to_buffer(b)); + bl_up_write(&aux->lock); + } else + bl_up_read(&aux->lock); + + dm_bufio_release_move(to_buffer(b), n); + return 0; +} + +int dm_bm_flush_and_unlock(struct dm_block_manager *bm, + struct dm_block *superblock) +{ + int r; + + r = dm_bufio_write_dirty_buffers(to_bufio(bm)); + if (unlikely(r)) + return r; + r = dm_bufio_issue_flush(to_bufio(bm)); + if (unlikely(r)) + return r; + + dm_bm_unlock(superblock); + + r = dm_bufio_write_dirty_buffers(to_bufio(bm)); + if (unlikely(r)) + return r; + r = dm_bufio_issue_flush(to_bufio(bm)); + if (unlikely(r)) + return r; + + return 0; +} + +u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor) +{ + return crc32c(~(u32) 0, data, len) ^ init_xor; +} +EXPORT_SYMBOL_GPL(dm_bm_checksum); + +/*----------------------------------------------------------------*/ + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); +MODULE_DESCRIPTION("Immutable metadata library for dm"); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h new file mode 100644 index 00000000000..924833d2dfa --- /dev/null +++ b/drivers/md/persistent-data/dm-block-manager.h @@ -0,0 +1,123 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_BLOCK_MANAGER_H +#define _LINUX_DM_BLOCK_MANAGER_H + +#include <linux/types.h> +#include <linux/blkdev.h> + +/*----------------------------------------------------------------*/ + +/* + * Block number. + */ +typedef uint64_t dm_block_t; +struct dm_block; + +dm_block_t dm_block_location(struct dm_block *b); +void *dm_block_data(struct dm_block *b); + +/*----------------------------------------------------------------*/ + +/* + * @name should be a unique identifier for the block manager, no longer + * than 32 chars. + * + * @max_held_per_thread should be the maximum number of locks, read or + * write, that an individual thread holds at any one time. + */ +struct dm_block_manager; +struct dm_block_manager *dm_block_manager_create( + struct block_device *bdev, unsigned block_size, + unsigned cache_size, unsigned max_held_per_thread); +void dm_block_manager_destroy(struct dm_block_manager *bm); + +unsigned dm_bm_block_size(struct dm_block_manager *bm); +dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm); + +/*----------------------------------------------------------------*/ + +/* + * The validator allows the caller to verify newly-read data and modify + * the data just before writing, e.g. to calculate checksums. It's + * important to be consistent with your use of validators. The only time + * you can change validators is if you call dm_bm_write_lock_zero. + */ +struct dm_block_validator { + const char *name; + void (*prepare_for_write)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); + + /* + * Return 0 if the checksum is valid or < 0 on error. + */ + int (*check)(struct dm_block_validator *v, struct dm_block *b, size_t block_size); +}; + +/*----------------------------------------------------------------*/ + +/* + * You can have multiple concurrent readers or a single writer holding a + * block lock. + */ + +/* + * dm_bm_lock() locks a block and returns through @result a pointer to + * memory that holds a copy of that block. If you have write-locked the + * block then any changes you make to memory pointed to by @result will be + * written back to the disk sometime after dm_bm_unlock is called. + */ +int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * The *_try_lock variants return -EWOULDBLOCK if the block isn't + * available immediately. + */ +int dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * Use dm_bm_write_lock_zero() when you know you're going to + * overwrite the block completely. It saves a disk read. + */ +int dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_bm_unlock(struct dm_block *b); + +/* + * An optimisation; we often want to copy a block's contents to a new + * block. eg, as part of the shadowing operation. It's far better for + * bufio to do this move behind the scenes than hold 2 locks and memcpy the + * data. + */ +int dm_bm_unlock_move(struct dm_block *b, dm_block_t n); + +/* + * It's a common idiom to have a superblock that should be committed last. + * + * @superblock should be write-locked on entry. It will be unlocked during + * this function. All dirty blocks are guaranteed to be written and flushed + * before the superblock. + * + * This method always blocks. + */ +int dm_bm_flush_and_unlock(struct dm_block_manager *bm, + struct dm_block *superblock); + +u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor); + +/*----------------------------------------------------------------*/ + +#endif /* _LINUX_DM_BLOCK_MANAGER_H */ diff --git a/drivers/md/persistent-data/dm-btree-internal.h b/drivers/md/persistent-data/dm-btree-internal.h new file mode 100644 index 00000000000..d279c768f8f --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-internal.h @@ -0,0 +1,137 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_BTREE_INTERNAL_H +#define DM_BTREE_INTERNAL_H + +#include "dm-btree.h" + +/*----------------------------------------------------------------*/ + +/* + * We'll need 2 accessor functions for n->csum and n->blocknr + * to support dm-btree-spine.c in that case. + */ + +enum node_flags { + INTERNAL_NODE = 1, + LEAF_NODE = 1 << 1 +}; + +/* + * Every btree node begins with this structure. Make sure it's a multiple + * of 8-bytes in size, otherwise the 64bit keys will be mis-aligned. + */ +struct node_header { + __le32 csum; + __le32 flags; + __le64 blocknr; /* Block this node is supposed to live in. */ + + __le32 nr_entries; + __le32 max_entries; + __le32 value_size; + __le32 padding; +} __packed; + +struct node { + struct node_header header; + __le64 keys[0]; +} __packed; + + +void inc_children(struct dm_transaction_manager *tm, struct node *n, + struct dm_btree_value_type *vt); + +int new_block(struct dm_btree_info *info, struct dm_block **result); +int unlock_block(struct dm_btree_info *info, struct dm_block *b); + +/* + * Spines keep track of the rolling locks. There are 2 variants, read-only + * and one that uses shadowing. These are separate structs to allow the + * type checker to spot misuse, for example accidentally calling read_lock + * on a shadow spine. + */ +struct ro_spine { + struct dm_btree_info *info; + + int count; + struct dm_block *nodes[2]; +}; + +void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info); +int exit_ro_spine(struct ro_spine *s); +int ro_step(struct ro_spine *s, dm_block_t new_child); +struct node *ro_node(struct ro_spine *s); + +struct shadow_spine { + struct dm_btree_info *info; + + int count; + struct dm_block *nodes[2]; + + dm_block_t root; +}; + +void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info); +int exit_shadow_spine(struct shadow_spine *s); + +int shadow_step(struct shadow_spine *s, dm_block_t b, + struct dm_btree_value_type *vt); + +/* + * The spine must have at least one entry before calling this. + */ +struct dm_block *shadow_current(struct shadow_spine *s); + +/* + * The spine must have at least two entries before calling this. + */ +struct dm_block *shadow_parent(struct shadow_spine *s); + +int shadow_has_parent(struct shadow_spine *s); + +int shadow_root(struct shadow_spine *s); + +/* + * Some inlines. + */ +static inline __le64 *key_ptr(struct node *n, uint32_t index) +{ + return n->keys + index; +} + +static inline void *value_base(struct node *n) +{ + return &n->keys[le32_to_cpu(n->header.max_entries)]; +} + +/* + * FIXME: Now that value size is stored in node we don't need the third parm. + */ +static inline void *value_ptr(struct node *n, uint32_t index, size_t value_size) +{ + BUG_ON(value_size != le32_to_cpu(n->header.value_size)); + return value_base(n) + (value_size * index); +} + +/* + * Assumes the values are suitably-aligned and converts to core format. + */ +static inline uint64_t value64(struct node *n, uint32_t index) +{ + __le64 *values_le = value_base(n); + + return le64_to_cpu(values_le[index]); +} + +/* + * Searching for a key within a single node. + */ +int lower_bound(struct node *n, uint64_t key); + +extern struct dm_block_validator btree_node_validator; + +#endif /* DM_BTREE_INTERNAL_H */ diff --git a/drivers/md/persistent-data/dm-btree-remove.c b/drivers/md/persistent-data/dm-btree-remove.c new file mode 100644 index 00000000000..65fd85ec651 --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-remove.c @@ -0,0 +1,566 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree.h" +#include "dm-btree-internal.h" +#include "dm-transaction-manager.h" + +#include <linux/module.h> + +/* + * Removing an entry from a btree + * ============================== + * + * A very important constraint for our btree is that no node, except the + * root, may have fewer than a certain number of entries. + * (MIN_ENTRIES <= nr_entries <= MAX_ENTRIES). + * + * Ensuring this is complicated by the way we want to only ever hold the + * locks on 2 nodes concurrently, and only change nodes in a top to bottom + * fashion. + * + * Each node may have a left or right sibling. When decending the spine, + * if a node contains only MIN_ENTRIES then we try and increase this to at + * least MIN_ENTRIES + 1. We do this in the following ways: + * + * [A] No siblings => this can only happen if the node is the root, in which + * case we copy the childs contents over the root. + * + * [B] No left sibling + * ==> rebalance(node, right sibling) + * + * [C] No right sibling + * ==> rebalance(left sibling, node) + * + * [D] Both siblings, total_entries(left, node, right) <= DEL_THRESHOLD + * ==> delete node adding it's contents to left and right + * + * [E] Both siblings, total_entries(left, node, right) > DEL_THRESHOLD + * ==> rebalance(left, node, right) + * + * After these operations it's possible that the our original node no + * longer contains the desired sub tree. For this reason this rebalancing + * is performed on the children of the current node. This also avoids + * having a special case for the root. + * + * Once this rebalancing has occurred we can then step into the child node + * for internal nodes. Or delete the entry for leaf nodes. + */ + +/* + * Some little utilities for moving node data around. + */ +static void node_shift(struct node *n, int shift) +{ + uint32_t nr_entries = le32_to_cpu(n->header.nr_entries); + uint32_t value_size = le32_to_cpu(n->header.value_size); + + if (shift < 0) { + shift = -shift; + BUG_ON(shift > nr_entries); + BUG_ON((void *) key_ptr(n, shift) >= value_ptr(n, shift, value_size)); + memmove(key_ptr(n, 0), + key_ptr(n, shift), + (nr_entries - shift) * sizeof(__le64)); + memmove(value_ptr(n, 0, value_size), + value_ptr(n, shift, value_size), + (nr_entries - shift) * value_size); + } else { + BUG_ON(nr_entries + shift > le32_to_cpu(n->header.max_entries)); + memmove(key_ptr(n, shift), + key_ptr(n, 0), + nr_entries * sizeof(__le64)); + memmove(value_ptr(n, shift, value_size), + value_ptr(n, 0, value_size), + nr_entries * value_size); + } +} + +static void node_copy(struct node *left, struct node *right, int shift) +{ + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t value_size = le32_to_cpu(left->header.value_size); + BUG_ON(value_size != le32_to_cpu(right->header.value_size)); + + if (shift < 0) { + shift = -shift; + BUG_ON(nr_left + shift > le32_to_cpu(left->header.max_entries)); + memcpy(key_ptr(left, nr_left), + key_ptr(right, 0), + shift * sizeof(__le64)); + memcpy(value_ptr(left, nr_left, value_size), + value_ptr(right, 0, value_size), + shift * value_size); + } else { + BUG_ON(shift > le32_to_cpu(right->header.max_entries)); + memcpy(key_ptr(right, 0), + key_ptr(left, nr_left - shift), + shift * sizeof(__le64)); + memcpy(value_ptr(right, 0, value_size), + value_ptr(left, nr_left - shift, value_size), + shift * value_size); + } +} + +/* + * Delete a specific entry from a leaf node. + */ +static void delete_at(struct node *n, unsigned index) +{ + unsigned nr_entries = le32_to_cpu(n->header.nr_entries); + unsigned nr_to_copy = nr_entries - (index + 1); + uint32_t value_size = le32_to_cpu(n->header.value_size); + BUG_ON(index >= nr_entries); + + if (nr_to_copy) { + memmove(key_ptr(n, index), + key_ptr(n, index + 1), + nr_to_copy * sizeof(__le64)); + + memmove(value_ptr(n, index, value_size), + value_ptr(n, index + 1, value_size), + nr_to_copy * value_size); + } + + n->header.nr_entries = cpu_to_le32(nr_entries - 1); +} + +static unsigned del_threshold(struct node *n) +{ + return le32_to_cpu(n->header.max_entries) / 3; +} + +static unsigned merge_threshold(struct node *n) +{ + /* + * The extra one is because we know we're potentially going to + * delete an entry. + */ + return 2 * (le32_to_cpu(n->header.max_entries) / 3) + 1; +} + +struct child { + unsigned index; + struct dm_block *block; + struct node *n; +}; + +static struct dm_btree_value_type le64_type = { + .context = NULL, + .size = sizeof(__le64), + .inc = NULL, + .dec = NULL, + .equal = NULL +}; + +static int init_child(struct dm_btree_info *info, struct node *parent, + unsigned index, struct child *result) +{ + int r, inc; + dm_block_t root; + + result->index = index; + root = value64(parent, index); + + r = dm_tm_shadow_block(info->tm, root, &btree_node_validator, + &result->block, &inc); + if (r) + return r; + + result->n = dm_block_data(result->block); + + if (inc) + inc_children(info->tm, result->n, &le64_type); + + *((__le64 *) value_ptr(parent, index, sizeof(__le64))) = + cpu_to_le64(dm_block_location(result->block)); + + return 0; +} + +static int exit_child(struct dm_btree_info *info, struct child *c) +{ + return dm_tm_unlock(info->tm, c->block); +} + +static void shift(struct node *left, struct node *right, int count) +{ + if (!count) + return; + + if (count > 0) { + node_shift(right, count); + node_copy(left, right, count); + } else { + node_copy(left, right, count); + node_shift(right, count); + } + + left->header.nr_entries = + cpu_to_le32(le32_to_cpu(left->header.nr_entries) - count); + BUG_ON(le32_to_cpu(left->header.nr_entries) > le32_to_cpu(left->header.max_entries)); + + right->header.nr_entries = + cpu_to_le32(le32_to_cpu(right->header.nr_entries) + count); + BUG_ON(le32_to_cpu(right->header.nr_entries) > le32_to_cpu(right->header.max_entries)); +} + +static void __rebalance2(struct dm_btree_info *info, struct node *parent, + struct child *l, struct child *r) +{ + struct node *left = l->n; + struct node *right = r->n; + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t nr_right = le32_to_cpu(right->header.nr_entries); + + if (nr_left + nr_right <= merge_threshold(left)) { + /* + * Merge + */ + node_copy(left, right, -nr_right); + left->header.nr_entries = cpu_to_le32(nr_left + nr_right); + delete_at(parent, r->index); + + /* + * We need to decrement the right block, but not it's + * children, since they're still referenced by left. + */ + dm_tm_dec(info->tm, dm_block_location(r->block)); + } else { + /* + * Rebalance. + */ + unsigned target_left = (nr_left + nr_right) / 2; + unsigned shift_ = nr_left - target_left; + BUG_ON(le32_to_cpu(left->header.max_entries) <= nr_left - shift_); + BUG_ON(le32_to_cpu(right->header.max_entries) <= nr_right + shift_); + shift(left, right, nr_left - target_left); + *key_ptr(parent, r->index) = right->keys[0]; + } +} + +static int rebalance2(struct shadow_spine *s, struct dm_btree_info *info, + unsigned left_index) +{ + int r; + struct node *parent; + struct child left, right; + + parent = dm_block_data(shadow_current(s)); + + r = init_child(info, parent, left_index, &left); + if (r) + return r; + + r = init_child(info, parent, left_index + 1, &right); + if (r) { + exit_child(info, &left); + return r; + } + + __rebalance2(info, parent, &left, &right); + + r = exit_child(info, &left); + if (r) { + exit_child(info, &right); + return r; + } + + return exit_child(info, &right); +} + +static void __rebalance3(struct dm_btree_info *info, struct node *parent, + struct child *l, struct child *c, struct child *r) +{ + struct node *left = l->n; + struct node *center = c->n; + struct node *right = r->n; + + uint32_t nr_left = le32_to_cpu(left->header.nr_entries); + uint32_t nr_center = le32_to_cpu(center->header.nr_entries); + uint32_t nr_right = le32_to_cpu(right->header.nr_entries); + uint32_t max_entries = le32_to_cpu(left->header.max_entries); + + unsigned target; + + BUG_ON(left->header.max_entries != center->header.max_entries); + BUG_ON(center->header.max_entries != right->header.max_entries); + + if (((nr_left + nr_center + nr_right) / 2) < merge_threshold(center)) { + /* + * Delete center node: + * + * We dump as many entries from center as possible into + * left, then the rest in right, then rebalance2. This + * wastes some cpu, but I want something simple atm. + */ + unsigned shift = min(max_entries - nr_left, nr_center); + + BUG_ON(nr_left + shift > max_entries); + node_copy(left, center, -shift); + left->header.nr_entries = cpu_to_le32(nr_left + shift); + + if (shift != nr_center) { + shift = nr_center - shift; + BUG_ON((nr_right + shift) >= max_entries); + node_shift(right, shift); + node_copy(center, right, shift); + right->header.nr_entries = cpu_to_le32(nr_right + shift); + } + *key_ptr(parent, r->index) = right->keys[0]; + + delete_at(parent, c->index); + r->index--; + + dm_tm_dec(info->tm, dm_block_location(c->block)); + __rebalance2(info, parent, l, r); + + return; + } + + /* + * Rebalance + */ + target = (nr_left + nr_center + nr_right) / 3; + BUG_ON(target > max_entries); + + /* + * Adjust the left node + */ + shift(left, center, nr_left - target); + + /* + * Adjust the right node + */ + shift(center, right, target - nr_right); + *key_ptr(parent, c->index) = center->keys[0]; + *key_ptr(parent, r->index) = right->keys[0]; +} + +static int rebalance3(struct shadow_spine *s, struct dm_btree_info *info, + unsigned left_index) +{ + int r; + struct node *parent = dm_block_data(shadow_current(s)); + struct child left, center, right; + + /* + * FIXME: fill out an array? + */ + r = init_child(info, parent, left_index, &left); + if (r) + return r; + + r = init_child(info, parent, left_index + 1, ¢er); + if (r) { + exit_child(info, &left); + return r; + } + + r = init_child(info, parent, left_index + 2, &right); + if (r) { + exit_child(info, &left); + exit_child(info, ¢er); + return r; + } + + __rebalance3(info, parent, &left, ¢er, &right); + + r = exit_child(info, &left); + if (r) { + exit_child(info, ¢er); + exit_child(info, &right); + return r; + } + + r = exit_child(info, ¢er); + if (r) { + exit_child(info, &right); + return r; + } + + r = exit_child(info, &right); + if (r) + return r; + + return 0; +} + +static int get_nr_entries(struct dm_transaction_manager *tm, + dm_block_t b, uint32_t *result) +{ + int r; + struct dm_block *block; + struct node *n; + + r = dm_tm_read_lock(tm, b, &btree_node_validator, &block); + if (r) + return r; + + n = dm_block_data(block); + *result = le32_to_cpu(n->header.nr_entries); + + return dm_tm_unlock(tm, block); +} + +static int rebalance_children(struct shadow_spine *s, + struct dm_btree_info *info, uint64_t key) +{ + int i, r, has_left_sibling, has_right_sibling; + uint32_t child_entries; + struct node *n; + + n = dm_block_data(shadow_current(s)); + + if (le32_to_cpu(n->header.nr_entries) == 1) { + struct dm_block *child; + dm_block_t b = value64(n, 0); + + r = dm_tm_read_lock(info->tm, b, &btree_node_validator, &child); + if (r) + return r; + + memcpy(n, dm_block_data(child), + dm_bm_block_size(dm_tm_get_bm(info->tm))); + r = dm_tm_unlock(info->tm, child); + if (r) + return r; + + dm_tm_dec(info->tm, dm_block_location(child)); + return 0; + } + + i = lower_bound(n, key); + if (i < 0) + return -ENODATA; + + r = get_nr_entries(info->tm, value64(n, i), &child_entries); + if (r) + return r; + + if (child_entries > del_threshold(n)) + return 0; + + has_left_sibling = i > 0; + has_right_sibling = i < (le32_to_cpu(n->header.nr_entries) - 1); + + if (!has_left_sibling) + r = rebalance2(s, info, i); + + else if (!has_right_sibling) + r = rebalance2(s, info, i - 1); + + else + r = rebalance3(s, info, i - 1); + + return r; +} + +static int do_leaf(struct node *n, uint64_t key, unsigned *index) +{ + int i = lower_bound(n, key); + + if ((i < 0) || + (i >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[i]) != key)) + return -ENODATA; + + *index = i; + + return 0; +} + +/* + * Prepares for removal from one level of the hierarchy. The caller must + * call delete_at() to remove the entry at index. + */ +static int remove_raw(struct shadow_spine *s, struct dm_btree_info *info, + struct dm_btree_value_type *vt, dm_block_t root, + uint64_t key, unsigned *index) +{ + int i = *index, r; + struct node *n; + + for (;;) { + r = shadow_step(s, root, vt); + if (r < 0) + break; + + /* + * We have to patch up the parent node, ugly, but I don't + * see a way to do this automatically as part of the spine + * op. + */ + if (shadow_has_parent(s)) { + __le64 location = cpu_to_le64(dm_block_location(shadow_current(s))); + memcpy(value_ptr(dm_block_data(shadow_parent(s)), i, sizeof(__le64)), + &location, sizeof(__le64)); + } + + n = dm_block_data(shadow_current(s)); + + if (le32_to_cpu(n->header.flags) & LEAF_NODE) + return do_leaf(n, key, index); + + r = rebalance_children(s, info, key); + if (r) + break; + + n = dm_block_data(shadow_current(s)); + if (le32_to_cpu(n->header.flags) & LEAF_NODE) + return do_leaf(n, key, index); + + i = lower_bound(n, key); + + /* + * We know the key is present, or else + * rebalance_children would have returned + * -ENODATA + */ + root = value64(n, i); + } + + return r; +} + +int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, dm_block_t *new_root) +{ + unsigned level, last_level = info->levels - 1; + int index = 0, r = 0; + struct shadow_spine spine; + struct node *n; + + init_shadow_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + r = remove_raw(&spine, info, + (level == last_level ? + &info->value_type : &le64_type), + root, keys[level], (unsigned *)&index); + if (r < 0) + break; + + n = dm_block_data(shadow_current(&spine)); + if (level != last_level) { + root = value64(n, index); + continue; + } + + BUG_ON(index < 0 || index >= le32_to_cpu(n->header.nr_entries)); + + if (info->value_type.dec) + info->value_type.dec(info->value_type.context, + value_ptr(n, index, info->value_type.size)); + + delete_at(n, index); + } + + *new_root = shadow_root(&spine); + exit_shadow_spine(&spine); + + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_remove); diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c new file mode 100644 index 00000000000..d9a7912ee8e --- /dev/null +++ b/drivers/md/persistent-data/dm-btree-spine.c @@ -0,0 +1,244 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree-internal.h" +#include "dm-transaction-manager.h" + +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "btree spine" + +/*----------------------------------------------------------------*/ + +#define BTREE_CSUM_XOR 121107 + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size); + +static void node_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + + h->blocknr = cpu_to_le64(dm_block_location(b)); + h->csum = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + + BUG_ON(node_check(v, b, 4096)); +} + +static int node_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct node *n = dm_block_data(b); + struct node_header *h = &n->header; + size_t value_size; + __le32 csum_disk; + uint32_t flags; + + if (dm_block_location(b) != le64_to_cpu(h->blocknr)) { + DMERR("node_check failed blocknr %llu wanted %llu", + le64_to_cpu(h->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags, + block_size - sizeof(__le32), + BTREE_CSUM_XOR)); + if (csum_disk != h->csum) { + DMERR("node_check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(h->csum)); + return -EILSEQ; + } + + value_size = le32_to_cpu(h->value_size); + + if (sizeof(struct node_header) + + (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) { + DMERR("node_check failed: max_entries too large"); + return -EILSEQ; + } + + if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) { + DMERR("node_check failed, too many entries"); + return -EILSEQ; + } + + /* + * The node must be either INTERNAL or LEAF. + */ + flags = le32_to_cpu(h->flags); + if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) { + DMERR("node_check failed, node is neither INTERNAL or LEAF"); + return -EILSEQ; + } + + return 0; +} + +struct dm_block_validator btree_node_validator = { + .name = "btree_node", + .prepare_for_write = node_prepare_for_write, + .check = node_check +}; + +/*----------------------------------------------------------------*/ + +static int bn_read_lock(struct dm_btree_info *info, dm_block_t b, + struct dm_block **result) +{ + return dm_tm_read_lock(info->tm, b, &btree_node_validator, result); +} + +static int bn_shadow(struct dm_btree_info *info, dm_block_t orig, + struct dm_btree_value_type *vt, + struct dm_block **result) +{ + int r, inc; + + r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator, + result, &inc); + if (!r && inc) + inc_children(info->tm, dm_block_data(*result), vt); + + return r; +} + +int new_block(struct dm_btree_info *info, struct dm_block **result) +{ + return dm_tm_new_block(info->tm, &btree_node_validator, result); +} + +int unlock_block(struct dm_btree_info *info, struct dm_block *b) +{ + return dm_tm_unlock(info->tm, b); +} + +/*----------------------------------------------------------------*/ + +void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; + s->nodes[0] = NULL; + s->nodes[1] = NULL; +} + +int exit_ro_spine(struct ro_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int ro_step(struct ro_spine *s, dm_block_t new_child) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_read_lock(s->info, new_child, s->nodes + s->count); + if (!r) + s->count++; + + return r; +} + +struct node *ro_node(struct ro_spine *s) +{ + struct dm_block *block; + + BUG_ON(!s->count); + block = s->nodes[s->count - 1]; + + return dm_block_data(block); +} + +/*----------------------------------------------------------------*/ + +void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) +{ + s->info = info; + s->count = 0; +} + +int exit_shadow_spine(struct shadow_spine *s) +{ + int r = 0, i; + + for (i = 0; i < s->count; i++) { + int r2 = unlock_block(s->info, s->nodes[i]); + if (r2 < 0) + r = r2; + } + + return r; +} + +int shadow_step(struct shadow_spine *s, dm_block_t b, + struct dm_btree_value_type *vt) +{ + int r; + + if (s->count == 2) { + r = unlock_block(s->info, s->nodes[0]); + if (r < 0) + return r; + s->nodes[0] = s->nodes[1]; + s->count--; + } + + r = bn_shadow(s->info, b, vt, s->nodes + s->count); + if (!r) { + if (!s->count) + s->root = dm_block_location(s->nodes[0]); + + s->count++; + } + + return r; +} + +struct dm_block *shadow_current(struct shadow_spine *s) +{ + BUG_ON(!s->count); + + return s->nodes[s->count - 1]; +} + +struct dm_block *shadow_parent(struct shadow_spine *s) +{ + BUG_ON(s->count != 2); + + return s->count == 2 ? s->nodes[0] : NULL; +} + +int shadow_has_parent(struct shadow_spine *s) +{ + return s->count >= 2; +} + +int shadow_root(struct shadow_spine *s) +{ + return s->root; +} diff --git a/drivers/md/persistent-data/dm-btree.c b/drivers/md/persistent-data/dm-btree.c new file mode 100644 index 00000000000..e0638be53ea --- /dev/null +++ b/drivers/md/persistent-data/dm-btree.c @@ -0,0 +1,805 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-btree-internal.h" +#include "dm-space-map.h" +#include "dm-transaction-manager.h" + +#include <linux/module.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "btree" + +/*---------------------------------------------------------------- + * Array manipulation + *--------------------------------------------------------------*/ +static void memcpy_disk(void *dest, const void *src, size_t len) + __dm_written_to_disk(src) +{ + memcpy(dest, src, len); + __dm_unbless_for_disk(src); +} + +static void array_insert(void *base, size_t elt_size, unsigned nr_elts, + unsigned index, void *elt) + __dm_written_to_disk(elt) +{ + if (index < nr_elts) + memmove(base + (elt_size * (index + 1)), + base + (elt_size * index), + (nr_elts - index) * elt_size); + + memcpy_disk(base + (elt_size * index), elt, elt_size); +} + +/*----------------------------------------------------------------*/ + +/* makes the assumption that no two keys are the same. */ +static int bsearch(struct node *n, uint64_t key, int want_hi) +{ + int lo = -1, hi = le32_to_cpu(n->header.nr_entries); + + while (hi - lo > 1) { + int mid = lo + ((hi - lo) / 2); + uint64_t mid_key = le64_to_cpu(n->keys[mid]); + + if (mid_key == key) + return mid; + + if (mid_key < key) + lo = mid; + else + hi = mid; + } + + return want_hi ? hi : lo; +} + +int lower_bound(struct node *n, uint64_t key) +{ + return bsearch(n, key, 0); +} + +void inc_children(struct dm_transaction_manager *tm, struct node *n, + struct dm_btree_value_type *vt) +{ + unsigned i; + uint32_t nr_entries = le32_to_cpu(n->header.nr_entries); + + if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) + for (i = 0; i < nr_entries; i++) + dm_tm_inc(tm, value64(n, i)); + else if (vt->inc) + for (i = 0; i < nr_entries; i++) + vt->inc(vt->context, + value_ptr(n, i, vt->size)); +} + +static int insert_at(size_t value_size, struct node *node, unsigned index, + uint64_t key, void *value) + __dm_written_to_disk(value) +{ + uint32_t nr_entries = le32_to_cpu(node->header.nr_entries); + __le64 key_le = cpu_to_le64(key); + + if (index > nr_entries || + index >= le32_to_cpu(node->header.max_entries)) { + DMERR("too many entries in btree node for insert"); + __dm_unbless_for_disk(value); + return -ENOMEM; + } + + __dm_bless_for_disk(&key_le); + + array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le); + array_insert(value_base(node), value_size, nr_entries, index, value); + node->header.nr_entries = cpu_to_le32(nr_entries + 1); + + return 0; +} + +/*----------------------------------------------------------------*/ + +/* + * We want 3n entries (for some n). This works more nicely for repeated + * insert remove loops than (2n + 1). + */ +static uint32_t calc_max_entries(size_t value_size, size_t block_size) +{ + uint32_t total, n; + size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */ + + block_size -= sizeof(struct node_header); + total = block_size / elt_size; + n = total / 3; /* rounds down */ + + return 3 * n; +} + +int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root) +{ + int r; + struct dm_block *b; + struct node *n; + size_t block_size; + uint32_t max_entries; + + r = new_block(info, &b); + if (r < 0) + return r; + + block_size = dm_bm_block_size(dm_tm_get_bm(info->tm)); + max_entries = calc_max_entries(info->value_type.size, block_size); + + n = dm_block_data(b); + memset(n, 0, block_size); + n->header.flags = cpu_to_le32(LEAF_NODE); + n->header.nr_entries = cpu_to_le32(0); + n->header.max_entries = cpu_to_le32(max_entries); + n->header.value_size = cpu_to_le32(info->value_type.size); + + *root = dm_block_location(b); + return unlock_block(info, b); +} +EXPORT_SYMBOL_GPL(dm_btree_empty); + +/*----------------------------------------------------------------*/ + +/* + * Deletion uses a recursive algorithm, since we have limited stack space + * we explicitly manage our own stack on the heap. + */ +#define MAX_SPINE_DEPTH 64 +struct frame { + struct dm_block *b; + struct node *n; + unsigned level; + unsigned nr_children; + unsigned current_child; +}; + +struct del_stack { + struct dm_transaction_manager *tm; + int top; + struct frame spine[MAX_SPINE_DEPTH]; +}; + +static int top_frame(struct del_stack *s, struct frame **f) +{ + if (s->top < 0) { + DMERR("btree deletion stack empty"); + return -EINVAL; + } + + *f = s->spine + s->top; + + return 0; +} + +static int unprocessed_frames(struct del_stack *s) +{ + return s->top >= 0; +} + +static int push_frame(struct del_stack *s, dm_block_t b, unsigned level) +{ + int r; + uint32_t ref_count; + + if (s->top >= MAX_SPINE_DEPTH - 1) { + DMERR("btree deletion stack out of memory"); + return -ENOMEM; + } + + r = dm_tm_ref(s->tm, b, &ref_count); + if (r) + return r; + + if (ref_count > 1) + /* + * This is a shared node, so we can just decrement it's + * reference counter and leave the children. + */ + dm_tm_dec(s->tm, b); + + else { + struct frame *f = s->spine + ++s->top; + + r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b); + if (r) { + s->top--; + return r; + } + + f->n = dm_block_data(f->b); + f->level = level; + f->nr_children = le32_to_cpu(f->n->header.nr_entries); + f->current_child = 0; + } + + return 0; +} + +static void pop_frame(struct del_stack *s) +{ + struct frame *f = s->spine + s->top--; + + dm_tm_dec(s->tm, dm_block_location(f->b)); + dm_tm_unlock(s->tm, f->b); +} + +int dm_btree_del(struct dm_btree_info *info, dm_block_t root) +{ + int r; + struct del_stack *s; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (!s) + return -ENOMEM; + s->tm = info->tm; + s->top = -1; + + r = push_frame(s, root, 1); + if (r) + goto out; + + while (unprocessed_frames(s)) { + uint32_t flags; + struct frame *f; + dm_block_t b; + + r = top_frame(s, &f); + if (r) + goto out; + + if (f->current_child >= f->nr_children) { + pop_frame(s); + continue; + } + + flags = le32_to_cpu(f->n->header.flags); + if (flags & INTERNAL_NODE) { + b = value64(f->n, f->current_child); + f->current_child++; + r = push_frame(s, b, f->level); + if (r) + goto out; + + } else if (f->level != (info->levels - 1)) { + b = value64(f->n, f->current_child); + f->current_child++; + r = push_frame(s, b, f->level + 1); + if (r) + goto out; + + } else { + if (info->value_type.dec) { + unsigned i; + + for (i = 0; i < f->nr_children; i++) + info->value_type.dec(info->value_type.context, + value_ptr(f->n, i, info->value_type.size)); + } + f->current_child = f->nr_children; + } + } + +out: + kfree(s); + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_del); + +/*----------------------------------------------------------------*/ + +static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key, + int (*search_fn)(struct node *, uint64_t), + uint64_t *result_key, void *v, size_t value_size) +{ + int i, r; + uint32_t flags, nr_entries; + + do { + r = ro_step(s, block); + if (r < 0) + return r; + + i = search_fn(ro_node(s), key); + + flags = le32_to_cpu(ro_node(s)->header.flags); + nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries); + if (i < 0 || i >= nr_entries) + return -ENODATA; + + if (flags & INTERNAL_NODE) + block = value64(ro_node(s), i); + + } while (!(flags & LEAF_NODE)); + + *result_key = le64_to_cpu(ro_node(s)->keys[i]); + memcpy(v, value_ptr(ro_node(s), i, value_size), value_size); + + return 0; +} + +int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value_le) +{ + unsigned level, last_level = info->levels - 1; + int r = -ENODATA; + uint64_t rkey; + __le64 internal_value_le; + struct ro_spine spine; + + init_ro_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + size_t size; + void *value_p; + + if (level == last_level) { + value_p = value_le; + size = info->value_type.size; + + } else { + value_p = &internal_value_le; + size = sizeof(uint64_t); + } + + r = btree_lookup_raw(&spine, root, keys[level], + lower_bound, &rkey, + value_p, size); + + if (!r) { + if (rkey != keys[level]) { + exit_ro_spine(&spine); + return -ENODATA; + } + } else { + exit_ro_spine(&spine); + return r; + } + + root = le64_to_cpu(internal_value_le); + } + exit_ro_spine(&spine); + + return r; +} +EXPORT_SYMBOL_GPL(dm_btree_lookup); + +/* + * Splits a node by creating a sibling node and shifting half the nodes + * contents across. Assumes there is a parent node, and it has room for + * another child. + * + * Before: + * +--------+ + * | Parent | + * +--------+ + * | + * v + * +----------+ + * | A ++++++ | + * +----------+ + * + * + * After: + * +--------+ + * | Parent | + * +--------+ + * | | + * v +------+ + * +---------+ | + * | A* +++ | v + * +---------+ +-------+ + * | B +++ | + * +-------+ + * + * Where A* is a shadow of A. + */ +static int btree_split_sibling(struct shadow_spine *s, dm_block_t root, + unsigned parent_index, uint64_t key) +{ + int r; + size_t size; + unsigned nr_left, nr_right; + struct dm_block *left, *right, *parent; + struct node *ln, *rn, *pn; + __le64 location; + + left = shadow_current(s); + + r = new_block(s->info, &right); + if (r < 0) + return r; + + ln = dm_block_data(left); + rn = dm_block_data(right); + + nr_left = le32_to_cpu(ln->header.nr_entries) / 2; + nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left; + + ln->header.nr_entries = cpu_to_le32(nr_left); + + rn->header.flags = ln->header.flags; + rn->header.nr_entries = cpu_to_le32(nr_right); + rn->header.max_entries = ln->header.max_entries; + rn->header.value_size = ln->header.value_size; + memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0])); + + size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ? + sizeof(uint64_t) : s->info->value_type.size; + memcpy(value_ptr(rn, 0, size), value_ptr(ln, nr_left, size), + size * nr_right); + + /* + * Patch up the parent + */ + parent = shadow_parent(s); + + pn = dm_block_data(parent); + location = cpu_to_le64(dm_block_location(left)); + __dm_bless_for_disk(&location); + memcpy_disk(value_ptr(pn, parent_index, sizeof(__le64)), + &location, sizeof(__le64)); + + location = cpu_to_le64(dm_block_location(right)); + __dm_bless_for_disk(&location); + + r = insert_at(sizeof(__le64), pn, parent_index + 1, + le64_to_cpu(rn->keys[0]), &location); + if (r) + return r; + + if (key < le64_to_cpu(rn->keys[0])) { + unlock_block(s->info, right); + s->nodes[1] = left; + } else { + unlock_block(s->info, left); + s->nodes[1] = right; + } + + return 0; +} + +/* + * Splits a node by creating two new children beneath the given node. + * + * Before: + * +----------+ + * | A ++++++ | + * +----------+ + * + * + * After: + * +------------+ + * | A (shadow) | + * +------------+ + * | | + * +------+ +----+ + * | | + * v v + * +-------+ +-------+ + * | B +++ | | C +++ | + * +-------+ +-------+ + */ +static int btree_split_beneath(struct shadow_spine *s, uint64_t key) +{ + int r; + size_t size; + unsigned nr_left, nr_right; + struct dm_block *left, *right, *new_parent; + struct node *pn, *ln, *rn; + __le64 val; + + new_parent = shadow_current(s); + + r = new_block(s->info, &left); + if (r < 0) + return r; + + r = new_block(s->info, &right); + if (r < 0) { + /* FIXME: put left */ + return r; + } + + pn = dm_block_data(new_parent); + ln = dm_block_data(left); + rn = dm_block_data(right); + + nr_left = le32_to_cpu(pn->header.nr_entries) / 2; + nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left; + + ln->header.flags = pn->header.flags; + ln->header.nr_entries = cpu_to_le32(nr_left); + ln->header.max_entries = pn->header.max_entries; + ln->header.value_size = pn->header.value_size; + + rn->header.flags = pn->header.flags; + rn->header.nr_entries = cpu_to_le32(nr_right); + rn->header.max_entries = pn->header.max_entries; + rn->header.value_size = pn->header.value_size; + + memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0])); + memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0])); + + size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ? + sizeof(__le64) : s->info->value_type.size; + memcpy(value_ptr(ln, 0, size), value_ptr(pn, 0, size), nr_left * size); + memcpy(value_ptr(rn, 0, size), value_ptr(pn, nr_left, size), + nr_right * size); + + /* new_parent should just point to l and r now */ + pn->header.flags = cpu_to_le32(INTERNAL_NODE); + pn->header.nr_entries = cpu_to_le32(2); + pn->header.max_entries = cpu_to_le32( + calc_max_entries(sizeof(__le64), + dm_bm_block_size( + dm_tm_get_bm(s->info->tm)))); + pn->header.value_size = cpu_to_le32(sizeof(__le64)); + + val = cpu_to_le64(dm_block_location(left)); + __dm_bless_for_disk(&val); + pn->keys[0] = ln->keys[0]; + memcpy_disk(value_ptr(pn, 0, sizeof(__le64)), &val, sizeof(__le64)); + + val = cpu_to_le64(dm_block_location(right)); + __dm_bless_for_disk(&val); + pn->keys[1] = rn->keys[0]; + memcpy_disk(value_ptr(pn, 1, sizeof(__le64)), &val, sizeof(__le64)); + + /* + * rejig the spine. This is ugly, since it knows too + * much about the spine + */ + if (s->nodes[0] != new_parent) { + unlock_block(s->info, s->nodes[0]); + s->nodes[0] = new_parent; + } + if (key < le64_to_cpu(rn->keys[0])) { + unlock_block(s->info, right); + s->nodes[1] = left; + } else { + unlock_block(s->info, left); + s->nodes[1] = right; + } + s->count = 2; + + return 0; +} + +static int btree_insert_raw(struct shadow_spine *s, dm_block_t root, + struct dm_btree_value_type *vt, + uint64_t key, unsigned *index) +{ + int r, i = *index, top = 1; + struct node *node; + + for (;;) { + r = shadow_step(s, root, vt); + if (r < 0) + return r; + + node = dm_block_data(shadow_current(s)); + + /* + * We have to patch up the parent node, ugly, but I don't + * see a way to do this automatically as part of the spine + * op. + */ + if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */ + __le64 location = cpu_to_le64(dm_block_location(shadow_current(s))); + + __dm_bless_for_disk(&location); + memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i, sizeof(uint64_t)), + &location, sizeof(__le64)); + } + + node = dm_block_data(shadow_current(s)); + + if (node->header.nr_entries == node->header.max_entries) { + if (top) + r = btree_split_beneath(s, key); + else + r = btree_split_sibling(s, root, i, key); + + if (r < 0) + return r; + } + + node = dm_block_data(shadow_current(s)); + + i = lower_bound(node, key); + + if (le32_to_cpu(node->header.flags) & LEAF_NODE) + break; + + if (i < 0) { + /* change the bounds on the lowest key */ + node->keys[0] = cpu_to_le64(key); + i = 0; + } + + root = value64(node, i); + top = 0; + } + + if (i < 0 || le64_to_cpu(node->keys[i]) != key) + i++; + + *index = i; + return 0; +} + +static int insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value) +{ + int r, need_insert; + unsigned level, index = -1, last_level = info->levels - 1; + dm_block_t block = root; + struct shadow_spine spine; + struct node *n; + struct dm_btree_value_type le64_type; + + le64_type.context = NULL; + le64_type.size = sizeof(__le64); + le64_type.inc = NULL; + le64_type.dec = NULL; + le64_type.equal = NULL; + + init_shadow_spine(&spine, info); + + for (level = 0; level < (info->levels - 1); level++) { + r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index); + if (r < 0) + goto bad; + + n = dm_block_data(shadow_current(&spine)); + need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[index]) != keys[level])); + + if (need_insert) { + dm_block_t new_tree; + __le64 new_le; + + r = dm_btree_empty(info, &new_tree); + if (r < 0) + goto bad; + + new_le = cpu_to_le64(new_tree); + __dm_bless_for_disk(&new_le); + + r = insert_at(sizeof(uint64_t), n, index, + keys[level], &new_le); + if (r) + goto bad; + } + + if (level < last_level) + block = value64(n, index); + } + + r = btree_insert_raw(&spine, block, &info->value_type, + keys[level], &index); + if (r < 0) + goto bad; + + n = dm_block_data(shadow_current(&spine)); + need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) || + (le64_to_cpu(n->keys[index]) != keys[level])); + + if (need_insert) { + if (inserted) + *inserted = 1; + + r = insert_at(info->value_type.size, n, index, + keys[level], value); + if (r) + goto bad_unblessed; + } else { + if (inserted) + *inserted = 0; + + if (info->value_type.dec && + (!info->value_type.equal || + !info->value_type.equal( + info->value_type.context, + value_ptr(n, index, info->value_type.size), + value))) { + info->value_type.dec(info->value_type.context, + value_ptr(n, index, info->value_type.size)); + } + memcpy_disk(value_ptr(n, index, info->value_type.size), + value, info->value_type.size); + } + + *new_root = shadow_root(&spine); + exit_shadow_spine(&spine); + + return 0; + +bad: + __dm_unbless_for_disk(value); +bad_unblessed: + exit_shadow_spine(&spine); + return r; +} + +int dm_btree_insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root) + __dm_written_to_disk(value) +{ + return insert(info, root, keys, value, new_root, NULL); +} +EXPORT_SYMBOL_GPL(dm_btree_insert); + +int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value) +{ + return insert(info, root, keys, value, new_root, inserted); +} +EXPORT_SYMBOL_GPL(dm_btree_insert_notify); + +/*----------------------------------------------------------------*/ + +static int find_highest_key(struct ro_spine *s, dm_block_t block, + uint64_t *result_key, dm_block_t *next_block) +{ + int i, r; + uint32_t flags; + + do { + r = ro_step(s, block); + if (r < 0) + return r; + + flags = le32_to_cpu(ro_node(s)->header.flags); + i = le32_to_cpu(ro_node(s)->header.nr_entries); + if (!i) + return -ENODATA; + else + i--; + + *result_key = le64_to_cpu(ro_node(s)->keys[i]); + if (next_block || flags & INTERNAL_NODE) + block = value64(ro_node(s), i); + + } while (flags & INTERNAL_NODE); + + if (next_block) + *next_block = block; + return 0; +} + +int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, + uint64_t *result_keys) +{ + int r = 0, count = 0, level; + struct ro_spine spine; + + init_ro_spine(&spine, info); + for (level = 0; level < info->levels; level++) { + r = find_highest_key(&spine, root, result_keys + level, + level == info->levels - 1 ? NULL : &root); + if (r == -ENODATA) { + r = 0; + break; + + } else if (r) + break; + + count++; + } + exit_ro_spine(&spine); + + return r ? r : count; +} +EXPORT_SYMBOL_GPL(dm_btree_find_highest_key); diff --git a/drivers/md/persistent-data/dm-btree.h b/drivers/md/persistent-data/dm-btree.h new file mode 100644 index 00000000000..ae02c84410f --- /dev/null +++ b/drivers/md/persistent-data/dm-btree.h @@ -0,0 +1,145 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#ifndef _LINUX_DM_BTREE_H +#define _LINUX_DM_BTREE_H + +#include "dm-block-manager.h" + +struct dm_transaction_manager; + +/*----------------------------------------------------------------*/ + +/* + * Annotations used to check on-disk metadata is handled as little-endian. + */ +#ifdef __CHECKER__ +# define __dm_written_to_disk(x) __releases(x) +# define __dm_reads_from_disk(x) __acquires(x) +# define __dm_bless_for_disk(x) __acquire(x) +# define __dm_unbless_for_disk(x) __release(x) +#else +# define __dm_written_to_disk(x) +# define __dm_reads_from_disk(x) +# define __dm_bless_for_disk(x) +# define __dm_unbless_for_disk(x) +#endif + +/*----------------------------------------------------------------*/ + +/* + * Manipulates hierarchical B+ trees with 64-bit keys and arbitrary-sized + * values. + */ + +/* + * Infomation about the values stored within the btree. + */ +struct dm_btree_value_type { + void *context; + + /* + * The size in bytes of each value. + */ + uint32_t size; + + /* + * Any of these methods can be safely set to NULL if you do not + * need the corresponding feature. + */ + + /* + * The btree is making a duplicate of the value, for instance + * because previously-shared btree nodes have now diverged. + * @value argument is the new copy that the copy function may modify. + * (Probably it just wants to increment a reference count + * somewhere.) This method is _not_ called for insertion of a new + * value: It is assumed the ref count is already 1. + */ + void (*inc)(void *context, void *value); + + /* + * This value is being deleted. The btree takes care of freeing + * the memory pointed to by @value. Often the del function just + * needs to decrement a reference count somewhere. + */ + void (*dec)(void *context, void *value); + + /* + * A test for equality between two values. When a value is + * overwritten with a new one, the old one has the dec method + * called _unless_ the new and old value are deemed equal. + */ + int (*equal)(void *context, void *value1, void *value2); +}; + +/* + * The shape and contents of a btree. + */ +struct dm_btree_info { + struct dm_transaction_manager *tm; + + /* + * Number of nested btrees. (Not the depth of a single tree.) + */ + unsigned levels; + struct dm_btree_value_type value_type; +}; + +/* + * Set up an empty tree. O(1). + */ +int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root); + +/* + * Delete a tree. O(n) - this is the slow one! It can also block, so + * please don't call it on an IO path. + */ +int dm_btree_del(struct dm_btree_info *info, dm_block_t root); + +/* + * All the lookup functions return -ENODATA if the key cannot be found. + */ + +/* + * Tries to find a key that matches exactly. O(ln(n)) + */ +int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value_le); + +/* + * Insertion (or overwrite an existing value). O(ln(n)) + */ +int dm_btree_insert(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root) + __dm_written_to_disk(value); + +/* + * A variant of insert that indicates whether it actually inserted or just + * overwrote. Useful if you're keeping track of the number of entries in a + * tree. + */ +int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, void *value, dm_block_t *new_root, + int *inserted) + __dm_written_to_disk(value); + +/* + * Remove a key if present. This doesn't remove empty sub trees. Normally + * subtrees represent a separate entity, like a snapshot map, so this is + * correct behaviour. O(ln(n)). + */ +int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, + uint64_t *keys, dm_block_t *new_root); + +/* + * Returns < 0 on failure. Otherwise the number of key entries that have + * been filled out. Remember trees can have zero entries, and as such have + * no highest key. + */ +int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, + uint64_t *result_keys); + +#endif /* _LINUX_DM_BTREE_H */ diff --git a/drivers/md/persistent-data/dm-persistent-data-internal.h b/drivers/md/persistent-data/dm-persistent-data-internal.h new file mode 100644 index 00000000000..c49e26fff36 --- /dev/null +++ b/drivers/md/persistent-data/dm-persistent-data-internal.h @@ -0,0 +1,19 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _DM_PERSISTENT_DATA_INTERNAL_H +#define _DM_PERSISTENT_DATA_INTERNAL_H + +#include "dm-block-manager.h" + +static inline unsigned dm_hash_block(dm_block_t b, unsigned hash_mask) +{ + const unsigned BIG_PRIME = 4294967291UL; + + return (((unsigned) b) * BIG_PRIME) & hash_mask; +} + +#endif /* _PERSISTENT_DATA_INTERNAL_H */ diff --git a/drivers/md/persistent-data/dm-space-map-checker.c b/drivers/md/persistent-data/dm-space-map-checker.c new file mode 100644 index 00000000000..bb44a937fe6 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-checker.c @@ -0,0 +1,437 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-checker.h" + +#include <linux/device-mapper.h> + +#ifdef CONFIG_DM_DEBUG_SPACE_MAPS + +#define DM_MSG_PREFIX "space map checker" + +/*----------------------------------------------------------------*/ + +struct count_array { + dm_block_t nr; + dm_block_t nr_free; + + uint32_t *counts; +}; + +static int ca_get_count(struct count_array *ca, dm_block_t b, uint32_t *count) +{ + if (b >= ca->nr) + return -EINVAL; + + *count = ca->counts[b]; + return 0; +} + +static int ca_count_more_than_one(struct count_array *ca, dm_block_t b, int *r) +{ + if (b >= ca->nr) + return -EINVAL; + + *r = ca->counts[b] > 1; + return 0; +} + +static int ca_set_count(struct count_array *ca, dm_block_t b, uint32_t count) +{ + uint32_t old_count; + + if (b >= ca->nr) + return -EINVAL; + + old_count = ca->counts[b]; + + if (!count && old_count) + ca->nr_free++; + + else if (count && !old_count) + ca->nr_free--; + + ca->counts[b] = count; + return 0; +} + +static int ca_inc_block(struct count_array *ca, dm_block_t b) +{ + if (b >= ca->nr) + return -EINVAL; + + ca_set_count(ca, b, ca->counts[b] + 1); + return 0; +} + +static int ca_dec_block(struct count_array *ca, dm_block_t b) +{ + if (b >= ca->nr) + return -EINVAL; + + BUG_ON(ca->counts[b] == 0); + ca_set_count(ca, b, ca->counts[b] - 1); + return 0; +} + +static int ca_create(struct count_array *ca, struct dm_space_map *sm) +{ + int r; + dm_block_t nr_blocks; + + r = dm_sm_get_nr_blocks(sm, &nr_blocks); + if (r) + return r; + + ca->nr = nr_blocks; + ca->nr_free = nr_blocks; + ca->counts = kzalloc(sizeof(*ca->counts) * nr_blocks, GFP_KERNEL); + if (!ca->counts) + return -ENOMEM; + + return 0; +} + +static int ca_load(struct count_array *ca, struct dm_space_map *sm) +{ + int r; + uint32_t count; + dm_block_t nr_blocks, i; + + r = dm_sm_get_nr_blocks(sm, &nr_blocks); + if (r) + return r; + + BUG_ON(ca->nr != nr_blocks); + + DMWARN("Loading debug space map from disk. This may take some time"); + for (i = 0; i < nr_blocks; i++) { + r = dm_sm_get_count(sm, i, &count); + if (r) { + DMERR("load failed"); + return r; + } + + ca_set_count(ca, i, count); + } + DMWARN("Load complete"); + + return 0; +} + +static int ca_extend(struct count_array *ca, dm_block_t extra_blocks) +{ + dm_block_t nr_blocks = ca->nr + extra_blocks; + uint32_t *counts = kzalloc(sizeof(*counts) * nr_blocks, GFP_KERNEL); + if (!counts) + return -ENOMEM; + + memcpy(counts, ca->counts, sizeof(*counts) * ca->nr); + kfree(ca->counts); + ca->nr = nr_blocks; + ca->nr_free += extra_blocks; + ca->counts = counts; + return 0; +} + +static int ca_commit(struct count_array *old, struct count_array *new) +{ + if (old->nr != new->nr) { + BUG_ON(old->nr > new->nr); + ca_extend(old, new->nr - old->nr); + } + + BUG_ON(old->nr != new->nr); + old->nr_free = new->nr_free; + memcpy(old->counts, new->counts, sizeof(*old->counts) * old->nr); + return 0; +} + +static void ca_destroy(struct count_array *ca) +{ + kfree(ca->counts); +} + +/*----------------------------------------------------------------*/ + +struct sm_checker { + struct dm_space_map sm; + + struct count_array old_counts; + struct count_array counts; + + struct dm_space_map *real_sm; +}; + +static void sm_checker_destroy(struct dm_space_map *sm) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + + dm_sm_destroy(smc->real_sm); + ca_destroy(&smc->old_counts); + ca_destroy(&smc->counts); + kfree(smc); +} + +static int sm_checker_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_get_nr_blocks(smc->real_sm, count); + if (!r) + BUG_ON(smc->old_counts.nr != *count); + return r; +} + +static int sm_checker_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_get_nr_free(smc->real_sm, count); + if (!r) { + /* + * Slow, but we know it's correct. + */ + dm_block_t b, n = 0; + for (b = 0; b < smc->old_counts.nr; b++) + if (smc->old_counts.counts[b] == 0 && + smc->counts.counts[b] == 0) + n++; + + if (n != *count) + DMERR("free block counts differ, checker %u, sm-disk:%u", + (unsigned) n, (unsigned) *count); + } + return r; +} + +static int sm_checker_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_new_block(smc->real_sm, b); + + if (!r) { + BUG_ON(*b >= smc->old_counts.nr); + BUG_ON(smc->old_counts.counts[*b] != 0); + BUG_ON(*b >= smc->counts.nr); + BUG_ON(smc->counts.counts[*b] != 0); + ca_set_count(&smc->counts, *b, 1); + } + + return r; +} + +static int sm_checker_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_inc_block(smc->real_sm, b); + int r2 = ca_inc_block(&smc->counts, b); + BUG_ON(r != r2); + return r; +} + +static int sm_checker_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_dec_block(smc->real_sm, b); + int r2 = ca_dec_block(&smc->counts, b); + BUG_ON(r != r2); + return r; +} + +static int sm_checker_get_count(struct dm_space_map *sm, dm_block_t b, uint32_t *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + uint32_t result2 = 0; + int r = dm_sm_get_count(smc->real_sm, b, result); + int r2 = ca_get_count(&smc->counts, b, &result2); + + BUG_ON(r != r2); + if (!r) + BUG_ON(*result != result2); + return r; +} + +static int sm_checker_count_more_than_one(struct dm_space_map *sm, dm_block_t b, int *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int result2 = 0; + int r = dm_sm_count_is_more_than_one(smc->real_sm, b, result); + int r2 = ca_count_more_than_one(&smc->counts, b, &result2); + + BUG_ON(r != r2); + if (!r) + BUG_ON(!(*result) && result2); + return r; +} + +static int sm_checker_set_count(struct dm_space_map *sm, dm_block_t b, uint32_t count) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + uint32_t old_rc; + int r = dm_sm_set_count(smc->real_sm, b, count); + int r2; + + BUG_ON(b >= smc->counts.nr); + old_rc = smc->counts.counts[b]; + r2 = ca_set_count(&smc->counts, b, count); + BUG_ON(r != r2); + + return r; +} + +static int sm_checker_commit(struct dm_space_map *sm) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r; + + r = dm_sm_commit(smc->real_sm); + if (r) + return r; + + r = ca_commit(&smc->old_counts, &smc->counts); + if (r) + return r; + + return 0; +} + +static int sm_checker_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + int r = dm_sm_extend(smc->real_sm, extra_blocks); + if (r) + return r; + + return ca_extend(&smc->counts, extra_blocks); +} + +static int sm_checker_root_size(struct dm_space_map *sm, size_t *result) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + return dm_sm_root_size(smc->real_sm, result); +} + +static int sm_checker_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len) +{ + struct sm_checker *smc = container_of(sm, struct sm_checker, sm); + return dm_sm_copy_root(smc->real_sm, copy_to_here_le, len); +} + +/*----------------------------------------------------------------*/ + +static struct dm_space_map ops_ = { + .destroy = sm_checker_destroy, + .get_nr_blocks = sm_checker_get_nr_blocks, + .get_nr_free = sm_checker_get_nr_free, + .inc_block = sm_checker_inc_block, + .dec_block = sm_checker_dec_block, + .new_block = sm_checker_new_block, + .get_count = sm_checker_get_count, + .count_is_more_than_one = sm_checker_count_more_than_one, + .set_count = sm_checker_set_count, + .commit = sm_checker_commit, + .extend = sm_checker_extend, + .root_size = sm_checker_root_size, + .copy_root = sm_checker_copy_root +}; + +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) +{ + int r; + struct sm_checker *smc; + + if (!sm) + return NULL; + + smc = kmalloc(sizeof(*smc), GFP_KERNEL); + if (!smc) + return NULL; + + memcpy(&smc->sm, &ops_, sizeof(smc->sm)); + r = ca_create(&smc->old_counts, sm); + if (r) { + kfree(smc); + return NULL; + } + + r = ca_create(&smc->counts, sm); + if (r) { + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + smc->real_sm = sm; + + r = ca_load(&smc->counts, sm); + if (r) { + ca_destroy(&smc->counts); + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + r = ca_commit(&smc->old_counts, &smc->counts); + if (r) { + ca_destroy(&smc->counts); + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + return &smc->sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create); + +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm) +{ + int r; + struct sm_checker *smc; + + if (!sm) + return NULL; + + smc = kmalloc(sizeof(*smc), GFP_KERNEL); + if (!smc) + return NULL; + + memcpy(&smc->sm, &ops_, sizeof(smc->sm)); + r = ca_create(&smc->old_counts, sm); + if (r) { + kfree(smc); + return NULL; + } + + r = ca_create(&smc->counts, sm); + if (r) { + ca_destroy(&smc->old_counts); + kfree(smc); + return NULL; + } + + smc->real_sm = sm; + return &smc->sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh); + +/*----------------------------------------------------------------*/ + +#else + +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm) +{ + return sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create); + +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm) +{ + return sm; +} +EXPORT_SYMBOL_GPL(dm_sm_checker_create_fresh); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/persistent-data/dm-space-map-checker.h b/drivers/md/persistent-data/dm-space-map-checker.h new file mode 100644 index 00000000000..444dccf6688 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-checker.h @@ -0,0 +1,26 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef SNAPSHOTS_SPACE_MAP_CHECKER_H +#define SNAPSHOTS_SPACE_MAP_CHECKER_H + +#include "dm-space-map.h" + +/*----------------------------------------------------------------*/ + +/* + * This space map wraps a real on-disk space map, and verifies all of its + * operations. It uses a lot of memory, so only use if you have a specific + * problem that you're debugging. + * + * Ownership of @sm passes. + */ +struct dm_space_map *dm_sm_checker_create(struct dm_space_map *sm); +struct dm_space_map *dm_sm_checker_create_fresh(struct dm_space_map *sm); + +/*----------------------------------------------------------------*/ + +#endif diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c new file mode 100644 index 00000000000..df2494c06cd --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-common.c @@ -0,0 +1,705 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-common.h" +#include "dm-transaction-manager.h" + +#include <linux/bitops.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map common" + +/*----------------------------------------------------------------*/ + +/* + * Index validator. + */ +#define INDEX_CSUM_XOR 160478 + +static void index_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_metadata_index *mi_le = dm_block_data(b); + + mi_le->blocknr = cpu_to_le64(dm_block_location(b)); + mi_le->csum = cpu_to_le32(dm_bm_checksum(&mi_le->padding, + block_size - sizeof(__le32), + INDEX_CSUM_XOR)); +} + +static int index_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_metadata_index *mi_le = dm_block_data(b); + __le32 csum_disk; + + if (dm_block_location(b) != le64_to_cpu(mi_le->blocknr)) { + DMERR("index_check failed blocknr %llu wanted %llu", + le64_to_cpu(mi_le->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&mi_le->padding, + block_size - sizeof(__le32), + INDEX_CSUM_XOR)); + if (csum_disk != mi_le->csum) { + DMERR("index_check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(mi_le->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator index_validator = { + .name = "index", + .prepare_for_write = index_prepare_for_write, + .check = index_check +}; + +/*----------------------------------------------------------------*/ + +/* + * Bitmap validator + */ +#define BITMAP_CSUM_XOR 240779 + +static void bitmap_prepare_for_write(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_bitmap_header *disk_header = dm_block_data(b); + + disk_header->blocknr = cpu_to_le64(dm_block_location(b)); + disk_header->csum = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, + block_size - sizeof(__le32), + BITMAP_CSUM_XOR)); +} + +static int bitmap_check(struct dm_block_validator *v, + struct dm_block *b, + size_t block_size) +{ + struct disk_bitmap_header *disk_header = dm_block_data(b); + __le32 csum_disk; + + if (dm_block_location(b) != le64_to_cpu(disk_header->blocknr)) { + DMERR("bitmap check failed blocknr %llu wanted %llu", + le64_to_cpu(disk_header->blocknr), dm_block_location(b)); + return -ENOTBLK; + } + + csum_disk = cpu_to_le32(dm_bm_checksum(&disk_header->not_used, + block_size - sizeof(__le32), + BITMAP_CSUM_XOR)); + if (csum_disk != disk_header->csum) { + DMERR("bitmap check failed csum %u wanted %u", + le32_to_cpu(csum_disk), le32_to_cpu(disk_header->csum)); + return -EILSEQ; + } + + return 0; +} + +static struct dm_block_validator dm_sm_bitmap_validator = { + .name = "sm_bitmap", + .prepare_for_write = bitmap_prepare_for_write, + .check = bitmap_check +}; + +/*----------------------------------------------------------------*/ + +#define ENTRIES_PER_WORD 32 +#define ENTRIES_SHIFT 5 + +static void *dm_bitmap_data(struct dm_block *b) +{ + return dm_block_data(b) + sizeof(struct disk_bitmap_header); +} + +#define WORD_MASK_HIGH 0xAAAAAAAAAAAAAAAAULL + +static unsigned bitmap_word_used(void *addr, unsigned b) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + + uint64_t bits = le64_to_cpu(*w_le); + uint64_t mask = (bits + WORD_MASK_HIGH + 1) & WORD_MASK_HIGH; + + return !(~bits & mask); +} + +static unsigned sm_lookup_bitmap(void *addr, unsigned b) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + unsigned hi, lo; + + b = (b & (ENTRIES_PER_WORD - 1)) << 1; + hi = !!test_bit_le(b, (void *) w_le); + lo = !!test_bit_le(b + 1, (void *) w_le); + return (hi << 1) | lo; +} + +static void sm_set_bitmap(void *addr, unsigned b, unsigned val) +{ + __le64 *words_le = addr; + __le64 *w_le = words_le + (b >> ENTRIES_SHIFT); + + b = (b & (ENTRIES_PER_WORD - 1)) << 1; + + if (val & 2) + __set_bit_le(b, (void *) w_le); + else + __clear_bit_le(b, (void *) w_le); + + if (val & 1) + __set_bit_le(b + 1, (void *) w_le); + else + __clear_bit_le(b + 1, (void *) w_le); +} + +static int sm_find_free(void *addr, unsigned begin, unsigned end, + unsigned *result) +{ + while (begin < end) { + if (!(begin & (ENTRIES_PER_WORD - 1)) && + bitmap_word_used(addr, begin)) { + begin += ENTRIES_PER_WORD; + continue; + } + + if (!sm_lookup_bitmap(addr, begin)) { + *result = begin; + return 0; + } + + begin++; + } + + return -ENOSPC; +} + +/*----------------------------------------------------------------*/ + +static int sm_ll_init(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + ll->tm = tm; + + ll->bitmap_info.tm = tm; + ll->bitmap_info.levels = 1; + + /* + * Because the new bitmap blocks are created via a shadow + * operation, the old entry has already had its reference count + * decremented and we don't need the btree to do any bookkeeping. + */ + ll->bitmap_info.value_type.size = sizeof(struct disk_index_entry); + ll->bitmap_info.value_type.inc = NULL; + ll->bitmap_info.value_type.dec = NULL; + ll->bitmap_info.value_type.equal = NULL; + + ll->ref_count_info.tm = tm; + ll->ref_count_info.levels = 1; + ll->ref_count_info.value_type.size = sizeof(uint32_t); + ll->ref_count_info.value_type.inc = NULL; + ll->ref_count_info.value_type.dec = NULL; + ll->ref_count_info.value_type.equal = NULL; + + ll->block_size = dm_bm_block_size(dm_tm_get_bm(tm)); + + if (ll->block_size > (1 << 30)) { + DMERR("block size too big to hold bitmaps"); + return -EINVAL; + } + + ll->entries_per_block = (ll->block_size - sizeof(struct disk_bitmap_header)) * + ENTRIES_PER_BYTE; + ll->nr_blocks = 0; + ll->bitmap_root = 0; + ll->ref_count_root = 0; + + return 0; +} + +int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks) +{ + int r; + dm_block_t i, nr_blocks, nr_indexes; + unsigned old_blocks, blocks; + + nr_blocks = ll->nr_blocks + extra_blocks; + old_blocks = dm_sector_div_up(ll->nr_blocks, ll->entries_per_block); + blocks = dm_sector_div_up(nr_blocks, ll->entries_per_block); + + nr_indexes = dm_sector_div_up(nr_blocks, ll->entries_per_block); + if (nr_indexes > ll->max_entries(ll)) { + DMERR("space map too large"); + return -EINVAL; + } + + for (i = old_blocks; i < blocks; i++) { + struct dm_block *b; + struct disk_index_entry idx; + + r = dm_tm_new_block(ll->tm, &dm_sm_bitmap_validator, &b); + if (r < 0) + return r; + idx.blocknr = cpu_to_le64(dm_block_location(b)); + + r = dm_tm_unlock(ll->tm, b); + if (r < 0) + return r; + + idx.nr_free = cpu_to_le32(ll->entries_per_block); + idx.none_free_before = 0; + + r = ll->save_ie(ll, i, &idx); + if (r < 0) + return r; + } + + ll->nr_blocks = nr_blocks; + return 0; +} + +int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result) +{ + int r; + dm_block_t index = b; + struct disk_index_entry ie_disk; + struct dm_block *blk; + + b = do_div(index, ll->entries_per_block); + r = ll->load_ie(ll, index, &ie_disk); + if (r < 0) + return r; + + r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &blk); + if (r < 0) + return r; + + *result = sm_lookup_bitmap(dm_bitmap_data(blk), b); + + return dm_tm_unlock(ll->tm, blk); +} + +int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result) +{ + __le32 le_rc; + int r = sm_ll_lookup_bitmap(ll, b, result); + + if (r) + return r; + + if (*result != 3) + return r; + + r = dm_btree_lookup(&ll->ref_count_info, ll->ref_count_root, &b, &le_rc); + if (r < 0) + return r; + + *result = le32_to_cpu(le_rc); + + return r; +} + +int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, + dm_block_t end, dm_block_t *result) +{ + int r; + struct disk_index_entry ie_disk; + dm_block_t i, index_begin = begin; + dm_block_t index_end = dm_sector_div_up(end, ll->entries_per_block); + + /* + * FIXME: Use shifts + */ + begin = do_div(index_begin, ll->entries_per_block); + end = do_div(end, ll->entries_per_block); + + for (i = index_begin; i < index_end; i++, begin = 0) { + struct dm_block *blk; + unsigned position; + uint32_t bit_end; + + r = ll->load_ie(ll, i, &ie_disk); + if (r < 0) + return r; + + if (le32_to_cpu(ie_disk.nr_free) == 0) + continue; + + r = dm_tm_read_lock(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &blk); + if (r < 0) + return r; + + bit_end = (i == index_end - 1) ? end : ll->entries_per_block; + + r = sm_find_free(dm_bitmap_data(blk), + max_t(unsigned, begin, le32_to_cpu(ie_disk.none_free_before)), + bit_end, &position); + if (r == -ENOSPC) { + /* + * This might happen because we started searching + * part way through the bitmap. + */ + dm_tm_unlock(ll->tm, blk); + continue; + + } else if (r < 0) { + dm_tm_unlock(ll->tm, blk); + return r; + } + + r = dm_tm_unlock(ll->tm, blk); + if (r < 0) + return r; + + *result = i * ll->entries_per_block + (dm_block_t) position; + return 0; + } + + return -ENOSPC; +} + +int sm_ll_insert(struct ll_disk *ll, dm_block_t b, + uint32_t ref_count, enum allocation_event *ev) +{ + int r; + uint32_t bit, old; + struct dm_block *nb; + dm_block_t index = b; + struct disk_index_entry ie_disk; + void *bm_le; + int inc; + + bit = do_div(index, ll->entries_per_block); + r = ll->load_ie(ll, index, &ie_disk); + if (r < 0) + return r; + + r = dm_tm_shadow_block(ll->tm, le64_to_cpu(ie_disk.blocknr), + &dm_sm_bitmap_validator, &nb, &inc); + if (r < 0) { + DMERR("dm_tm_shadow_block() failed"); + return r; + } + ie_disk.blocknr = cpu_to_le64(dm_block_location(nb)); + + bm_le = dm_bitmap_data(nb); + old = sm_lookup_bitmap(bm_le, bit); + + if (ref_count <= 2) { + sm_set_bitmap(bm_le, bit, ref_count); + + r = dm_tm_unlock(ll->tm, nb); + if (r < 0) + return r; + +#if 0 + /* FIXME: dm_btree_remove doesn't handle this yet */ + if (old > 2) { + r = dm_btree_remove(&ll->ref_count_info, + ll->ref_count_root, + &b, &ll->ref_count_root); + if (r) + return r; + } +#endif + + } else { + __le32 le_rc = cpu_to_le32(ref_count); + + sm_set_bitmap(bm_le, bit, 3); + r = dm_tm_unlock(ll->tm, nb); + if (r < 0) + return r; + + __dm_bless_for_disk(&le_rc); + r = dm_btree_insert(&ll->ref_count_info, ll->ref_count_root, + &b, &le_rc, &ll->ref_count_root); + if (r < 0) { + DMERR("ref count insert failed"); + return r; + } + } + + if (ref_count && !old) { + *ev = SM_ALLOC; + ll->nr_allocated++; + ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) - 1); + if (le32_to_cpu(ie_disk.none_free_before) == bit) + ie_disk.none_free_before = cpu_to_le32(bit + 1); + + } else if (old && !ref_count) { + *ev = SM_FREE; + ll->nr_allocated--; + ie_disk.nr_free = cpu_to_le32(le32_to_cpu(ie_disk.nr_free) + 1); + ie_disk.none_free_before = cpu_to_le32(min(le32_to_cpu(ie_disk.none_free_before), bit)); + } + + return ll->save_ie(ll, index, &ie_disk); +} + +int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + int r; + uint32_t rc; + + r = sm_ll_lookup(ll, b, &rc); + if (r) + return r; + + return sm_ll_insert(ll, b, rc + 1, ev); +} + +int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev) +{ + int r; + uint32_t rc; + + r = sm_ll_lookup(ll, b, &rc); + if (r) + return r; + + if (!rc) + return -EINVAL; + + return sm_ll_insert(ll, b, rc - 1, ev); +} + +int sm_ll_commit(struct ll_disk *ll) +{ + return ll->commit(ll); +} + +/*----------------------------------------------------------------*/ + +static int metadata_ll_load_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + memcpy(ie, ll->mi_le.index + index, sizeof(*ie)); + return 0; +} + +static int metadata_ll_save_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + memcpy(ll->mi_le.index + index, ie, sizeof(*ie)); + return 0; +} + +static int metadata_ll_init_index(struct ll_disk *ll) +{ + int r; + struct dm_block *b; + + r = dm_tm_new_block(ll->tm, &index_validator, &b); + if (r < 0) + return r; + + memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); + ll->bitmap_root = dm_block_location(b); + + return dm_tm_unlock(ll->tm, b); +} + +static int metadata_ll_open(struct ll_disk *ll) +{ + int r; + struct dm_block *block; + + r = dm_tm_read_lock(ll->tm, ll->bitmap_root, + &index_validator, &block); + if (r) + return r; + + memcpy(&ll->mi_le, dm_block_data(block), sizeof(ll->mi_le)); + return dm_tm_unlock(ll->tm, block); +} + +static dm_block_t metadata_ll_max_entries(struct ll_disk *ll) +{ + return MAX_METADATA_BITMAPS; +} + +static int metadata_ll_commit(struct ll_disk *ll) +{ + int r, inc; + struct dm_block *b; + + r = dm_tm_shadow_block(ll->tm, ll->bitmap_root, &index_validator, &b, &inc); + if (r) + return r; + + memcpy(dm_block_data(b), &ll->mi_le, sizeof(ll->mi_le)); + ll->bitmap_root = dm_block_location(b); + + return dm_tm_unlock(ll->tm, b); +} + +int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + int r; + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = metadata_ll_load_ie; + ll->save_ie = metadata_ll_save_ie; + ll->init_index = metadata_ll_init_index; + ll->open_index = metadata_ll_open; + ll->max_entries = metadata_ll_max_entries; + ll->commit = metadata_ll_commit; + + ll->nr_blocks = 0; + ll->nr_allocated = 0; + + r = ll->init_index(ll); + if (r < 0) + return r; + + r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); + if (r < 0) + return r; + + return 0; +} + +int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct disk_sm_root *smr = root_le; + + if (len < sizeof(struct disk_sm_root)) { + DMERR("sm_metadata root too small"); + return -ENOMEM; + } + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = metadata_ll_load_ie; + ll->save_ie = metadata_ll_save_ie; + ll->init_index = metadata_ll_init_index; + ll->open_index = metadata_ll_open; + ll->max_entries = metadata_ll_max_entries; + ll->commit = metadata_ll_commit; + + ll->nr_blocks = le64_to_cpu(smr->nr_blocks); + ll->nr_allocated = le64_to_cpu(smr->nr_allocated); + ll->bitmap_root = le64_to_cpu(smr->bitmap_root); + ll->ref_count_root = le64_to_cpu(smr->ref_count_root); + + return ll->open_index(ll); +} + +/*----------------------------------------------------------------*/ + +static int disk_ll_load_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + return dm_btree_lookup(&ll->bitmap_info, ll->bitmap_root, &index, ie); +} + +static int disk_ll_save_ie(struct ll_disk *ll, dm_block_t index, + struct disk_index_entry *ie) +{ + __dm_bless_for_disk(ie); + return dm_btree_insert(&ll->bitmap_info, ll->bitmap_root, + &index, ie, &ll->bitmap_root); +} + +static int disk_ll_init_index(struct ll_disk *ll) +{ + return dm_btree_empty(&ll->bitmap_info, &ll->bitmap_root); +} + +static int disk_ll_open(struct ll_disk *ll) +{ + /* nothing to do */ + return 0; +} + +static dm_block_t disk_ll_max_entries(struct ll_disk *ll) +{ + return -1ULL; +} + +static int disk_ll_commit(struct ll_disk *ll) +{ + return 0; +} + +int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm) +{ + int r; + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = disk_ll_load_ie; + ll->save_ie = disk_ll_save_ie; + ll->init_index = disk_ll_init_index; + ll->open_index = disk_ll_open; + ll->max_entries = disk_ll_max_entries; + ll->commit = disk_ll_commit; + + ll->nr_blocks = 0; + ll->nr_allocated = 0; + + r = ll->init_index(ll); + if (r < 0) + return r; + + r = dm_btree_empty(&ll->ref_count_info, &ll->ref_count_root); + if (r < 0) + return r; + + return 0; +} + +int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct disk_sm_root *smr = root_le; + + if (len < sizeof(struct disk_sm_root)) { + DMERR("sm_metadata root too small"); + return -ENOMEM; + } + + r = sm_ll_init(ll, tm); + if (r < 0) + return r; + + ll->load_ie = disk_ll_load_ie; + ll->save_ie = disk_ll_save_ie; + ll->init_index = disk_ll_init_index; + ll->open_index = disk_ll_open; + ll->max_entries = disk_ll_max_entries; + ll->commit = disk_ll_commit; + + ll->nr_blocks = le64_to_cpu(smr->nr_blocks); + ll->nr_allocated = le64_to_cpu(smr->nr_allocated); + ll->bitmap_root = le64_to_cpu(smr->bitmap_root); + ll->ref_count_root = le64_to_cpu(smr->ref_count_root); + + return ll->open_index(ll); +} + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-space-map-common.h b/drivers/md/persistent-data/dm-space-map-common.h new file mode 100644 index 00000000000..8f220821a9a --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-common.h @@ -0,0 +1,126 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_SPACE_MAP_COMMON_H +#define DM_SPACE_MAP_COMMON_H + +#include "dm-btree.h" + +/*----------------------------------------------------------------*/ + +/* + * Low level disk format + * + * Bitmap btree + * ------------ + * + * Each value stored in the btree is an index_entry. This points to a + * block that is used as a bitmap. Within the bitmap hold 2 bits per + * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and + * REF_COUNT = many. + * + * Refcount btree + * -------------- + * + * Any entry that has a ref count higher than 2 gets entered in the ref + * count tree. The leaf values for this tree is the 32-bit ref count. + */ + +struct disk_index_entry { + __le64 blocknr; + __le32 nr_free; + __le32 none_free_before; +} __packed; + + +#define MAX_METADATA_BITMAPS 255 +struct disk_metadata_index { + __le32 csum; + __le32 padding; + __le64 blocknr; + + struct disk_index_entry index[MAX_METADATA_BITMAPS]; +} __packed; + +struct ll_disk; + +typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result); +typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie); +typedef int (*init_index_fn)(struct ll_disk *ll); +typedef int (*open_index_fn)(struct ll_disk *ll); +typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll); +typedef int (*commit_fn)(struct ll_disk *ll); + +struct ll_disk { + struct dm_transaction_manager *tm; + struct dm_btree_info bitmap_info; + struct dm_btree_info ref_count_info; + + uint32_t block_size; + uint32_t entries_per_block; + dm_block_t nr_blocks; + dm_block_t nr_allocated; + + /* + * bitmap_root may be a btree root or a simple index. + */ + dm_block_t bitmap_root; + + dm_block_t ref_count_root; + + struct disk_metadata_index mi_le; + load_ie_fn load_ie; + save_ie_fn save_ie; + init_index_fn init_index; + open_index_fn open_index; + max_index_entries_fn max_entries; + commit_fn commit; +}; + +struct disk_sm_root { + __le64 nr_blocks; + __le64 nr_allocated; + __le64 bitmap_root; + __le64 ref_count_root; +} __packed; + +#define ENTRIES_PER_BYTE 4 + +struct disk_bitmap_header { + __le32 csum; + __le32 not_used; + __le64 blocknr; +} __packed; + +enum allocation_event { + SM_NONE, + SM_ALLOC, + SM_FREE, +}; + +/*----------------------------------------------------------------*/ + +int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks); +int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result); +int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result); +int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin, + dm_block_t end, dm_block_t *result); +int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev); +int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev); +int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev); +int sm_ll_commit(struct ll_disk *ll); + +int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm); +int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len); + +int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm); +int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm, + void *root_le, size_t len); + +/*----------------------------------------------------------------*/ + +#endif /* DM_SPACE_MAP_COMMON_H */ diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c new file mode 100644 index 00000000000..aeff7852cf7 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-disk.c @@ -0,0 +1,335 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map-checker.h" +#include "dm-space-map-common.h" +#include "dm-space-map-disk.h" +#include "dm-space-map.h" +#include "dm-transaction-manager.h" + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map disk" + +/*----------------------------------------------------------------*/ + +/* + * Space map interface. + */ +struct sm_disk { + struct dm_space_map sm; + + struct ll_disk ll; + struct ll_disk old_ll; + + dm_block_t begin; + dm_block_t nr_allocated_this_transaction; +}; + +static void sm_disk_destroy(struct dm_space_map *sm) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + kfree(smd); +} + +static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + return sm_ll_extend(&smd->ll, extra_blocks); +} + +static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + *count = smd->old_ll.nr_blocks; + + return 0; +} + +static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction; + + return 0; +} + +static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + return sm_ll_lookup(&smd->ll, b, result); +} + +static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b, + int *result) +{ + int r; + uint32_t count; + + r = sm_disk_get_count(sm, b, &count); + if (r) + return r; + + return count > 1; +} + +static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + int r; + uint32_t old_count; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_insert(&smd->ll, b, count, &ev); + if (!r) { + switch (ev) { + case SM_NONE: + break; + + case SM_ALLOC: + /* + * This _must_ be free in the prior transaction + * otherwise we've lost atomicity. + */ + smd->nr_allocated_this_transaction++; + break; + + case SM_FREE: + /* + * It's only free if it's also free in the last + * transaction. + */ + r = sm_ll_lookup(&smd->old_ll, b, &old_count); + if (r) + return r; + + if (!old_count) + smd->nr_allocated_this_transaction--; + break; + } + } + + return r; +} + +static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + int r; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_inc(&smd->ll, b, &ev); + if (!r && (ev == SM_ALLOC)) + /* + * This _must_ be free in the prior transaction + * otherwise we've lost atomicity. + */ + smd->nr_allocated_this_transaction++; + + return r; +} + +static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + int r; + uint32_t old_count; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_ll_dec(&smd->ll, b, &ev); + if (!r && (ev == SM_FREE)) { + /* + * It's only free if it's also free in the last + * transaction. + */ + r = sm_ll_lookup(&smd->old_ll, b, &old_count); + if (r) + return r; + + if (!old_count) + smd->nr_allocated_this_transaction--; + } + + return r; +} + +static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + int r; + enum allocation_event ev; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + /* FIXME: we should loop round a couple of times */ + r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b); + if (r) + return r; + + smd->begin = *b + 1; + r = sm_ll_inc(&smd->ll, *b, &ev); + if (!r) { + BUG_ON(ev != SM_ALLOC); + smd->nr_allocated_this_transaction++; + } + + return r; +} + +static int sm_disk_commit(struct dm_space_map *sm) +{ + int r; + dm_block_t nr_free; + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + + r = sm_disk_get_nr_free(sm, &nr_free); + if (r) + return r; + + r = sm_ll_commit(&smd->ll); + if (r) + return r; + + memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll)); + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + + r = sm_disk_get_nr_free(sm, &nr_free); + if (r) + return r; + + return 0; +} + +static int sm_disk_root_size(struct dm_space_map *sm, size_t *result) +{ + *result = sizeof(struct disk_sm_root); + + return 0; +} + +static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max) +{ + struct sm_disk *smd = container_of(sm, struct sm_disk, sm); + struct disk_sm_root root_le; + + root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks); + root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated); + root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root); + root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root); + + if (max < sizeof(root_le)) + return -ENOSPC; + + memcpy(where_le, &root_le, sizeof(root_le)); + + return 0; +} + +/*----------------------------------------------------------------*/ + +static struct dm_space_map ops = { + .destroy = sm_disk_destroy, + .extend = sm_disk_extend, + .get_nr_blocks = sm_disk_get_nr_blocks, + .get_nr_free = sm_disk_get_nr_free, + .get_count = sm_disk_get_count, + .count_is_more_than_one = sm_disk_count_is_more_than_one, + .set_count = sm_disk_set_count, + .inc_block = sm_disk_inc_block, + .dec_block = sm_disk_dec_block, + .new_block = sm_disk_new_block, + .commit = sm_disk_commit, + .root_size = sm_disk_root_size, + .copy_root = sm_disk_copy_root +}; + +static struct dm_space_map *dm_sm_disk_create_real( + struct dm_transaction_manager *tm, + dm_block_t nr_blocks) +{ + int r; + struct sm_disk *smd; + + smd = kmalloc(sizeof(*smd), GFP_KERNEL); + if (!smd) + return ERR_PTR(-ENOMEM); + + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + memcpy(&smd->sm, &ops, sizeof(smd->sm)); + + r = sm_ll_new_disk(&smd->ll, tm); + if (r) + goto bad; + + r = sm_ll_extend(&smd->ll, nr_blocks); + if (r) + goto bad; + + r = sm_disk_commit(&smd->sm); + if (r) + goto bad; + + return &smd->sm; + +bad: + kfree(smd); + return ERR_PTR(r); +} + +struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, + dm_block_t nr_blocks) +{ + struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks); + return dm_sm_checker_create_fresh(sm); +} +EXPORT_SYMBOL_GPL(dm_sm_disk_create); + +static struct dm_space_map *dm_sm_disk_open_real( + struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct sm_disk *smd; + + smd = kmalloc(sizeof(*smd), GFP_KERNEL); + if (!smd) + return ERR_PTR(-ENOMEM); + + smd->begin = 0; + smd->nr_allocated_this_transaction = 0; + memcpy(&smd->sm, &ops, sizeof(smd->sm)); + + r = sm_ll_open_disk(&smd->ll, tm, root_le, len); + if (r) + goto bad; + + r = sm_disk_commit(&smd->sm); + if (r) + goto bad; + + return &smd->sm; + +bad: + kfree(smd); + return ERR_PTR(r); +} + +struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + return dm_sm_checker_create( + dm_sm_disk_open_real(tm, root_le, len)); +} +EXPORT_SYMBOL_GPL(dm_sm_disk_open); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-space-map-disk.h b/drivers/md/persistent-data/dm-space-map-disk.h new file mode 100644 index 00000000000..447a0a9a2d9 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-disk.h @@ -0,0 +1,25 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_SPACE_MAP_DISK_H +#define _LINUX_DM_SPACE_MAP_DISK_H + +#include "dm-block-manager.h" + +struct dm_space_map; +struct dm_transaction_manager; + +/* + * Unfortunately we have to use two-phase construction due to the cycle + * between the tm and sm. + */ +struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm, + dm_block_t nr_blocks); + +struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm, + void *root, size_t len); + +#endif /* _LINUX_DM_SPACE_MAP_DISK_H */ diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c new file mode 100644 index 00000000000..e89ae5e7a51 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-metadata.c @@ -0,0 +1,596 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#include "dm-space-map.h" +#include "dm-space-map-common.h" +#include "dm-space-map-metadata.h" + +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "space map metadata" + +/*----------------------------------------------------------------*/ + +/* + * Space map interface. + * + * The low level disk format is written using the standard btree and + * transaction manager. This means that performing disk operations may + * cause us to recurse into the space map in order to allocate new blocks. + * For this reason we have a pool of pre-allocated blocks large enough to + * service any metadata_ll_disk operation. + */ + +/* + * FIXME: we should calculate this based on the size of the device. + * Only the metadata space map needs this functionality. + */ +#define MAX_RECURSIVE_ALLOCATIONS 1024 + +enum block_op_type { + BOP_INC, + BOP_DEC +}; + +struct block_op { + enum block_op_type type; + dm_block_t block; +}; + +struct sm_metadata { + struct dm_space_map sm; + + struct ll_disk ll; + struct ll_disk old_ll; + + dm_block_t begin; + + unsigned recursion_count; + unsigned allocated_this_transaction; + unsigned nr_uncommitted; + struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS]; +}; + +static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b) +{ + struct block_op *op; + + if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) { + DMERR("too many recursive allocations"); + return -ENOMEM; + } + + op = smm->uncommitted + smm->nr_uncommitted++; + op->type = type; + op->block = b; + + return 0; +} + +static int commit_bop(struct sm_metadata *smm, struct block_op *op) +{ + int r = 0; + enum allocation_event ev; + + switch (op->type) { + case BOP_INC: + r = sm_ll_inc(&smm->ll, op->block, &ev); + break; + + case BOP_DEC: + r = sm_ll_dec(&smm->ll, op->block, &ev); + break; + } + + return r; +} + +static void in(struct sm_metadata *smm) +{ + smm->recursion_count++; +} + +static int out(struct sm_metadata *smm) +{ + int r = 0; + + /* + * If we're not recursing then very bad things are happening. + */ + if (!smm->recursion_count) { + DMERR("lost track of recursion depth"); + return -ENOMEM; + } + + if (smm->recursion_count == 1 && smm->nr_uncommitted) { + while (smm->nr_uncommitted && !r) { + smm->nr_uncommitted--; + r = commit_bop(smm, smm->uncommitted + + smm->nr_uncommitted); + if (r) + break; + } + } + + smm->recursion_count--; + + return r; +} + +/* + * When using the out() function above, we often want to combine an error + * code for the operation run in the recursive context with that from + * out(). + */ +static int combine_errors(int r1, int r2) +{ + return r1 ? r1 : r2; +} + +static int recursing(struct sm_metadata *smm) +{ + return smm->recursion_count; +} + +static void sm_metadata_destroy(struct dm_space_map *sm) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + kfree(smm); +} + +static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("doesn't support extend"); + return -EINVAL; +} + +static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks; + + return 0; +} + +static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated - + smm->allocated_this_transaction; + + return 0; +} + +static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + int r, i; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + unsigned adjustment = 0; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + r = sm_ll_lookup(&smm->ll, b, result); + if (r) + return r; + + *result += adjustment; + + return 0; +} + +static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + int r, i, adjustment = 0; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + uint32_t rc; + + /* + * We may have some uncommitted adjustments to add. This list + * should always be really short. + */ + for (i = 0; i < smm->nr_uncommitted; i++) { + struct block_op *op = smm->uncommitted + i; + + if (op->block != b) + continue; + + switch (op->type) { + case BOP_INC: + adjustment++; + break; + + case BOP_DEC: + adjustment--; + break; + } + } + + if (adjustment > 1) { + *result = 1; + return 0; + } + + r = sm_ll_lookup_bitmap(&smm->ll, b, &rc); + if (r) + return r; + + if (rc == 3) + /* + * We err on the side of caution, and always return true. + */ + *result = 1; + else + *result = rc + adjustment > 1; + + return 0; +} + +static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + int r, r2; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (smm->recursion_count) { + DMERR("cannot recurse set_count()"); + return -EINVAL; + } + + in(smm); + r = sm_ll_insert(&smm->ll, b, count, &ev); + r2 = out(smm); + + return combine_errors(r, r2); +} + +static int sm_metadata_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + if (recursing(smm)) + r = add_bop(smm, BOP_DEC, b); + else { + in(smm); + r = sm_ll_dec(&smm->ll, b, &ev); + r2 = out(smm); + } + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b) +{ + int r, r2 = 0; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_find_free_block(&smm->old_ll, smm->begin, smm->old_ll.nr_blocks, b); + if (r) + return r; + + smm->begin = *b + 1; + + if (recursing(smm)) + r = add_bop(smm, BOP_INC, *b); + else { + in(smm); + r = sm_ll_inc(&smm->ll, *b, &ev); + r2 = out(smm); + } + + if (!r) + smm->allocated_this_transaction++; + + return combine_errors(r, r2); +} + +static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + int r = sm_metadata_new_block_(sm, b); + if (r) + DMERR("out of metadata space"); + return r; +} + +static int sm_metadata_commit(struct dm_space_map *sm) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_commit(&smm->ll); + if (r) + return r; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + smm->begin = 0; + smm->allocated_this_transaction = 0; + + return 0; +} + +static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result) +{ + *result = sizeof(struct disk_sm_root); + + return 0; +} + +static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + struct disk_sm_root root_le; + + root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks); + root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated); + root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root); + root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root); + + if (max < sizeof(root_le)) + return -ENOSPC; + + memcpy(where_le, &root_le, sizeof(root_le)); + + return 0; +} + +static struct dm_space_map ops = { + .destroy = sm_metadata_destroy, + .extend = sm_metadata_extend, + .get_nr_blocks = sm_metadata_get_nr_blocks, + .get_nr_free = sm_metadata_get_nr_free, + .get_count = sm_metadata_get_count, + .count_is_more_than_one = sm_metadata_count_is_more_than_one, + .set_count = sm_metadata_set_count, + .inc_block = sm_metadata_inc_block, + .dec_block = sm_metadata_dec_block, + .new_block = sm_metadata_new_block, + .commit = sm_metadata_commit, + .root_size = sm_metadata_root_size, + .copy_root = sm_metadata_copy_root +}; + +/*----------------------------------------------------------------*/ + +/* + * When a new space map is created that manages its own space. We use + * this tiny bootstrap allocator. + */ +static void sm_bootstrap_destroy(struct dm_space_map *sm) +{ +} + +static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + DMERR("boostrap doesn't support extend"); + + return -EINVAL; +} + +static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return smm->ll.nr_blocks; +} + +static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + *count = smm->ll.nr_blocks - smm->begin; + + return 0; +} + +static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return b < smm->begin ? 1 : 0; +} + +static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + *result = 0; + + return 0; +} + +static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + DMERR("boostrap doesn't support set_count"); + + return -EINVAL; +} + +static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + /* + * We know the entire device is unused. + */ + if (smm->begin == smm->ll.nr_blocks) + return -ENOSPC; + + *b = smm->begin++; + + return 0; +} + +static int sm_bootstrap_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_INC, b); +} + +static int sm_bootstrap_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + return add_bop(smm, BOP_DEC, b); +} + +static int sm_bootstrap_commit(struct dm_space_map *sm) +{ + return 0; +} + +static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result) +{ + DMERR("boostrap doesn't support root_size"); + + return -EINVAL; +} + +static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where, + size_t max) +{ + DMERR("boostrap doesn't support copy_root"); + + return -EINVAL; +} + +static struct dm_space_map bootstrap_ops = { + .destroy = sm_bootstrap_destroy, + .extend = sm_bootstrap_extend, + .get_nr_blocks = sm_bootstrap_get_nr_blocks, + .get_nr_free = sm_bootstrap_get_nr_free, + .get_count = sm_bootstrap_get_count, + .count_is_more_than_one = sm_bootstrap_count_is_more_than_one, + .set_count = sm_bootstrap_set_count, + .inc_block = sm_bootstrap_inc_block, + .dec_block = sm_bootstrap_dec_block, + .new_block = sm_bootstrap_new_block, + .commit = sm_bootstrap_commit, + .root_size = sm_bootstrap_root_size, + .copy_root = sm_bootstrap_copy_root +}; + +/*----------------------------------------------------------------*/ + +struct dm_space_map *dm_sm_metadata_init(void) +{ + struct sm_metadata *smm; + + smm = kmalloc(sizeof(*smm), GFP_KERNEL); + if (!smm) + return ERR_PTR(-ENOMEM); + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + return &smm->sm; +} + +int dm_sm_metadata_create(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + dm_block_t nr_blocks, + dm_block_t superblock) +{ + int r; + dm_block_t i; + enum allocation_event ev; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + smm->begin = superblock + 1; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm)); + + r = sm_ll_new_metadata(&smm->ll, tm); + if (r) + return r; + + r = sm_ll_extend(&smm->ll, nr_blocks); + if (r) + return r; + + memcpy(&smm->sm, &ops, sizeof(smm->sm)); + + /* + * Now we need to update the newly created data structures with the + * allocated blocks that they were built from. + */ + for (i = superblock; !r && i < smm->begin; i++) + r = sm_ll_inc(&smm->ll, i, &ev); + + if (r) + return r; + + return sm_metadata_commit(sm); +} + +int dm_sm_metadata_open(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + void *root_le, size_t len) +{ + int r; + struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm); + + r = sm_ll_open_metadata(&smm->ll, tm, root_le, len); + if (r) + return r; + + smm->begin = 0; + smm->recursion_count = 0; + smm->allocated_this_transaction = 0; + smm->nr_uncommitted = 0; + + memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll)); + return 0; +} diff --git a/drivers/md/persistent-data/dm-space-map-metadata.h b/drivers/md/persistent-data/dm-space-map-metadata.h new file mode 100644 index 00000000000..39bba0801cf --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map-metadata.h @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef DM_SPACE_MAP_METADATA_H +#define DM_SPACE_MAP_METADATA_H + +#include "dm-transaction-manager.h" + +/* + * Unfortunately we have to use two-phase construction due to the cycle + * between the tm and sm. + */ +struct dm_space_map *dm_sm_metadata_init(void); + +/* + * Create a fresh space map. + */ +int dm_sm_metadata_create(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + dm_block_t nr_blocks, + dm_block_t superblock); + +/* + * Open from a previously-recorded root. + */ +int dm_sm_metadata_open(struct dm_space_map *sm, + struct dm_transaction_manager *tm, + void *root_le, size_t len); + +#endif /* DM_SPACE_MAP_METADATA_H */ diff --git a/drivers/md/persistent-data/dm-space-map.h b/drivers/md/persistent-data/dm-space-map.h new file mode 100644 index 00000000000..1cbfc6b1638 --- /dev/null +++ b/drivers/md/persistent-data/dm-space-map.h @@ -0,0 +1,134 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_SPACE_MAP_H +#define _LINUX_DM_SPACE_MAP_H + +#include "dm-block-manager.h" + +/* + * struct dm_space_map keeps a record of how many times each block in a device + * is referenced. It needs to be fixed on disk as part of the transaction. + */ +struct dm_space_map { + void (*destroy)(struct dm_space_map *sm); + + /* + * You must commit before allocating the newly added space. + */ + int (*extend)(struct dm_space_map *sm, dm_block_t extra_blocks); + + /* + * Extensions do not appear in this count until after commit has + * been called. + */ + int (*get_nr_blocks)(struct dm_space_map *sm, dm_block_t *count); + + /* + * Space maps must never allocate a block from the previous + * transaction, in case we need to rollback. This complicates the + * semantics of get_nr_free(), it should return the number of blocks + * that are available for allocation _now_. For instance you may + * have blocks with a zero reference count that will not be + * available for allocation until after the next commit. + */ + int (*get_nr_free)(struct dm_space_map *sm, dm_block_t *count); + + int (*get_count)(struct dm_space_map *sm, dm_block_t b, uint32_t *result); + int (*count_is_more_than_one)(struct dm_space_map *sm, dm_block_t b, + int *result); + int (*set_count)(struct dm_space_map *sm, dm_block_t b, uint32_t count); + + int (*commit)(struct dm_space_map *sm); + + int (*inc_block)(struct dm_space_map *sm, dm_block_t b); + int (*dec_block)(struct dm_space_map *sm, dm_block_t b); + + /* + * new_block will increment the returned block. + */ + int (*new_block)(struct dm_space_map *sm, dm_block_t *b); + + /* + * The root contains all the information needed to fix the space map. + * Generally this info is small, so squirrel it away in a disk block + * along with other info. + */ + int (*root_size)(struct dm_space_map *sm, size_t *result); + int (*copy_root)(struct dm_space_map *sm, void *copy_to_here_le, size_t len); +}; + +/*----------------------------------------------------------------*/ + +static inline void dm_sm_destroy(struct dm_space_map *sm) +{ + sm->destroy(sm); +} + +static inline int dm_sm_extend(struct dm_space_map *sm, dm_block_t extra_blocks) +{ + return sm->extend(sm, extra_blocks); +} + +static inline int dm_sm_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count) +{ + return sm->get_nr_blocks(sm, count); +} + +static inline int dm_sm_get_nr_free(struct dm_space_map *sm, dm_block_t *count) +{ + return sm->get_nr_free(sm, count); +} + +static inline int dm_sm_get_count(struct dm_space_map *sm, dm_block_t b, + uint32_t *result) +{ + return sm->get_count(sm, b, result); +} + +static inline int dm_sm_count_is_more_than_one(struct dm_space_map *sm, + dm_block_t b, int *result) +{ + return sm->count_is_more_than_one(sm, b, result); +} + +static inline int dm_sm_set_count(struct dm_space_map *sm, dm_block_t b, + uint32_t count) +{ + return sm->set_count(sm, b, count); +} + +static inline int dm_sm_commit(struct dm_space_map *sm) +{ + return sm->commit(sm); +} + +static inline int dm_sm_inc_block(struct dm_space_map *sm, dm_block_t b) +{ + return sm->inc_block(sm, b); +} + +static inline int dm_sm_dec_block(struct dm_space_map *sm, dm_block_t b) +{ + return sm->dec_block(sm, b); +} + +static inline int dm_sm_new_block(struct dm_space_map *sm, dm_block_t *b) +{ + return sm->new_block(sm, b); +} + +static inline int dm_sm_root_size(struct dm_space_map *sm, size_t *result) +{ + return sm->root_size(sm, result); +} + +static inline int dm_sm_copy_root(struct dm_space_map *sm, void *copy_to_here_le, size_t len) +{ + return sm->copy_root(sm, copy_to_here_le, len); +} + +#endif /* _LINUX_DM_SPACE_MAP_H */ diff --git a/drivers/md/persistent-data/dm-transaction-manager.c b/drivers/md/persistent-data/dm-transaction-manager.c new file mode 100644 index 00000000000..728e89a3f97 --- /dev/null +++ b/drivers/md/persistent-data/dm-transaction-manager.c @@ -0,0 +1,400 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ +#include "dm-transaction-manager.h" +#include "dm-space-map.h" +#include "dm-space-map-checker.h" +#include "dm-space-map-disk.h" +#include "dm-space-map-metadata.h" +#include "dm-persistent-data-internal.h" + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/device-mapper.h> + +#define DM_MSG_PREFIX "transaction manager" + +/*----------------------------------------------------------------*/ + +struct shadow_info { + struct hlist_node hlist; + dm_block_t where; +}; + +/* + * It would be nice if we scaled with the size of transaction. + */ +#define HASH_SIZE 256 +#define HASH_MASK (HASH_SIZE - 1) + +struct dm_transaction_manager { + int is_clone; + struct dm_transaction_manager *real; + + struct dm_block_manager *bm; + struct dm_space_map *sm; + + spinlock_t lock; + struct hlist_head buckets[HASH_SIZE]; +}; + +/*----------------------------------------------------------------*/ + +static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b) +{ + int r = 0; + unsigned bucket = dm_hash_block(b, HASH_MASK); + struct shadow_info *si; + struct hlist_node *n; + + spin_lock(&tm->lock); + hlist_for_each_entry(si, n, tm->buckets + bucket, hlist) + if (si->where == b) { + r = 1; + break; + } + spin_unlock(&tm->lock); + + return r; +} + +/* + * This can silently fail if there's no memory. We're ok with this since + * creating redundant shadows causes no harm. + */ +static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b) +{ + unsigned bucket; + struct shadow_info *si; + + si = kmalloc(sizeof(*si), GFP_NOIO); + if (si) { + si->where = b; + bucket = dm_hash_block(b, HASH_MASK); + spin_lock(&tm->lock); + hlist_add_head(&si->hlist, tm->buckets + bucket); + spin_unlock(&tm->lock); + } +} + +static void wipe_shadow_table(struct dm_transaction_manager *tm) +{ + struct shadow_info *si; + struct hlist_node *n, *tmp; + struct hlist_head *bucket; + int i; + + spin_lock(&tm->lock); + for (i = 0; i < HASH_SIZE; i++) { + bucket = tm->buckets + i; + hlist_for_each_entry_safe(si, n, tmp, bucket, hlist) + kfree(si); + + INIT_HLIST_HEAD(bucket); + } + + spin_unlock(&tm->lock); +} + +/*----------------------------------------------------------------*/ + +static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm, + struct dm_space_map *sm) +{ + int i; + struct dm_transaction_manager *tm; + + tm = kmalloc(sizeof(*tm), GFP_KERNEL); + if (!tm) + return ERR_PTR(-ENOMEM); + + tm->is_clone = 0; + tm->real = NULL; + tm->bm = bm; + tm->sm = sm; + + spin_lock_init(&tm->lock); + for (i = 0; i < HASH_SIZE; i++) + INIT_HLIST_HEAD(tm->buckets + i); + + return tm; +} + +struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real) +{ + struct dm_transaction_manager *tm; + + tm = kmalloc(sizeof(*tm), GFP_KERNEL); + if (tm) { + tm->is_clone = 1; + tm->real = real; + } + + return tm; +} +EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone); + +void dm_tm_destroy(struct dm_transaction_manager *tm) +{ + kfree(tm); +} +EXPORT_SYMBOL_GPL(dm_tm_destroy); + +int dm_tm_pre_commit(struct dm_transaction_manager *tm) +{ + int r; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_commit(tm->sm); + if (r < 0) + return r; + + return 0; +} +EXPORT_SYMBOL_GPL(dm_tm_pre_commit); + +int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root) +{ + if (tm->is_clone) + return -EWOULDBLOCK; + + wipe_shadow_table(tm); + + return dm_bm_flush_and_unlock(tm->bm, root); +} +EXPORT_SYMBOL_GPL(dm_tm_commit); + +int dm_tm_new_block(struct dm_transaction_manager *tm, + struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + dm_block_t new_block; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_new_block(tm->sm, &new_block); + if (r < 0) + return r; + + r = dm_bm_write_lock_zero(tm->bm, new_block, v, result); + if (r < 0) { + dm_sm_dec_block(tm->sm, new_block); + return r; + } + + /* + * New blocks count as shadows in that they don't need to be + * shadowed again. + */ + insert_shadow(tm, new_block); + + return 0; +} + +static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, + struct dm_block **result) +{ + int r; + dm_block_t new; + struct dm_block *orig_block; + + r = dm_sm_new_block(tm->sm, &new); + if (r < 0) + return r; + + r = dm_sm_dec_block(tm->sm, orig); + if (r < 0) + return r; + + r = dm_bm_read_lock(tm->bm, orig, v, &orig_block); + if (r < 0) + return r; + + r = dm_bm_unlock_move(orig_block, new); + if (r < 0) { + dm_bm_unlock(orig_block); + return r; + } + + return dm_bm_write_lock(tm->bm, new, v, result); +} + +int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, struct dm_block **result, + int *inc_children) +{ + int r; + + if (tm->is_clone) + return -EWOULDBLOCK; + + r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children); + if (r < 0) + return r; + + if (is_shadow(tm, orig) && !*inc_children) + return dm_bm_write_lock(tm->bm, orig, v, result); + + r = __shadow_block(tm, orig, v, result); + if (r < 0) + return r; + insert_shadow(tm, dm_block_location(*result)); + + return r; +} + +int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **blk) +{ + if (tm->is_clone) + return dm_bm_read_try_lock(tm->real->bm, b, v, blk); + + return dm_bm_read_lock(tm->bm, b, v, blk); +} + +int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b) +{ + return dm_bm_unlock(b); +} +EXPORT_SYMBOL_GPL(dm_tm_unlock); + +void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b) +{ + /* + * The non-blocking clone doesn't support this. + */ + BUG_ON(tm->is_clone); + + dm_sm_inc_block(tm->sm, b); +} +EXPORT_SYMBOL_GPL(dm_tm_inc); + +void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b) +{ + /* + * The non-blocking clone doesn't support this. + */ + BUG_ON(tm->is_clone); + + dm_sm_dec_block(tm->sm, b); +} +EXPORT_SYMBOL_GPL(dm_tm_dec); + +int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b, + uint32_t *result) +{ + if (tm->is_clone) + return -EWOULDBLOCK; + + return dm_sm_get_count(tm->sm, b, result); +} + +struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm) +{ + return tm->bm; +} + +/*----------------------------------------------------------------*/ + +static int dm_tm_create_internal(struct dm_block_manager *bm, + dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, + struct dm_block **sblock, + int create) +{ + int r; + struct dm_space_map *inner; + + inner = dm_sm_metadata_init(); + if (IS_ERR(inner)) + return PTR_ERR(inner); + + *tm = dm_tm_create(bm, inner); + if (IS_ERR(*tm)) { + dm_sm_destroy(inner); + return PTR_ERR(*tm); + } + + if (create) { + r = dm_bm_write_lock_zero(dm_tm_get_bm(*tm), sb_location, + sb_validator, sblock); + if (r < 0) { + DMERR("couldn't lock superblock"); + goto bad1; + } + + r = dm_sm_metadata_create(inner, *tm, dm_bm_nr_blocks(bm), + sb_location); + if (r) { + DMERR("couldn't create metadata space map"); + goto bad2; + } + + *sm = dm_sm_checker_create(inner); + if (!*sm) + goto bad2; + + } else { + r = dm_bm_write_lock(dm_tm_get_bm(*tm), sb_location, + sb_validator, sblock); + if (r < 0) { + DMERR("couldn't lock superblock"); + goto bad1; + } + + r = dm_sm_metadata_open(inner, *tm, + dm_block_data(*sblock) + root_offset, + root_max_len); + if (r) { + DMERR("couldn't open metadata space map"); + goto bad2; + } + + *sm = dm_sm_checker_create(inner); + if (!*sm) + goto bad2; + } + + return 0; + +bad2: + dm_tm_unlock(*tm, *sblock); +bad1: + dm_tm_destroy(*tm); + dm_sm_destroy(inner); + return r; +} + +int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock) +{ + return dm_tm_create_internal(bm, sb_location, sb_validator, + 0, 0, tm, sm, sblock, 1); +} +EXPORT_SYMBOL_GPL(dm_tm_create_with_sm); + +int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock) +{ + return dm_tm_create_internal(bm, sb_location, sb_validator, root_offset, + root_max_len, tm, sm, sblock, 0); +} +EXPORT_SYMBOL_GPL(dm_tm_open_with_sm); + +/*----------------------------------------------------------------*/ diff --git a/drivers/md/persistent-data/dm-transaction-manager.h b/drivers/md/persistent-data/dm-transaction-manager.h new file mode 100644 index 00000000000..6da784871db --- /dev/null +++ b/drivers/md/persistent-data/dm-transaction-manager.h @@ -0,0 +1,130 @@ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_TRANSACTION_MANAGER_H +#define _LINUX_DM_TRANSACTION_MANAGER_H + +#include "dm-block-manager.h" + +struct dm_transaction_manager; +struct dm_space_map; + +/*----------------------------------------------------------------*/ + +/* + * This manages the scope of a transaction. It also enforces immutability + * of the on-disk data structures by limiting access to writeable blocks. + * + * Clients should not fiddle with the block manager directly. + */ + +void dm_tm_destroy(struct dm_transaction_manager *tm); + +/* + * The non-blocking version of a transaction manager is intended for use in + * fast path code that needs to do lookups e.g. a dm mapping function. + * You create the non-blocking variant from a normal tm. The interface is + * the same, except that most functions will just return -EWOULDBLOCK. + * Methods that return void yet may block should not be called on a clone + * viz. dm_tm_inc, dm_tm_dec. Call dm_tm_destroy() as you would with a normal + * tm when you've finished with it. You may not destroy the original prior + * to clones. + */ +struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real); + +/* + * We use a 2-phase commit here. + * + * i) In the first phase the block manager is told to start flushing, and + * the changes to the space map are written to disk. You should interrogate + * your particular space map to get detail of its root node etc. to be + * included in your superblock. + * + * ii) @root will be committed last. You shouldn't use more than the + * first 512 bytes of @root if you wish the transaction to survive a power + * failure. You *must* have a write lock held on @root for both stage (i) + * and (ii). The commit will drop the write lock. + */ +int dm_tm_pre_commit(struct dm_transaction_manager *tm); +int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root); + +/* + * These methods are the only way to get hold of a writeable block. + */ + +/* + * dm_tm_new_block() is pretty self-explanatory. Make sure you do actually + * write to the whole of @data before you unlock, otherwise you could get + * a data leak. (The other option is for tm_new_block() to zero new blocks + * before handing them out, which will be redundant in most, if not all, + * cases). + * Zeroes the new block and returns with write lock held. + */ +int dm_tm_new_block(struct dm_transaction_manager *tm, + struct dm_block_validator *v, + struct dm_block **result); + +/* + * dm_tm_shadow_block() allocates a new block and copies the data from @orig + * to it. It then decrements the reference count on original block. Use + * this to update the contents of a block in a data structure, don't + * confuse this with a clone - you shouldn't access the orig block after + * this operation. Because the tm knows the scope of the transaction it + * can optimise requests for a shadow of a shadow to a no-op. Don't forget + * to unlock when you've finished with the shadow. + * + * The @inc_children flag is used to tell the caller whether it needs to + * adjust reference counts for children. (Data in the block may refer to + * other blocks.) + * + * Shadowing implicitly drops a reference on @orig so you must not have + * it locked when you call this. + */ +int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig, + struct dm_block_validator *v, + struct dm_block **result, int *inc_children); + +/* + * Read access. You can lock any block you want. If there's a write lock + * on it outstanding then it'll block. + */ +int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b, + struct dm_block_validator *v, + struct dm_block **result); + +int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b); + +/* + * Functions for altering the reference count of a block directly. + */ +void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b); + +void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b); + +int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b, + uint32_t *result); + +struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm); + +/* + * A little utility that ties the knot by producing a transaction manager + * that has a space map managed by the transaction manager... + * + * Returns a tm that has an open transaction to write the new disk sm. + * Caller should store the new sm root and commit. + */ +int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock); + +int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, + struct dm_block_validator *sb_validator, + size_t root_offset, size_t root_max_len, + struct dm_transaction_manager **tm, + struct dm_space_map **sm, struct dm_block **sblock); + +#endif /* _LINUX_DM_TRANSACTION_MANAGER_H */ |