/* * Copyright (C) 2003 Sistina Software * * This file is released under the LGPL. */ #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/vmalloc.h> #include "dm-log.h" #include "dm-io.h" #define DM_MSG_PREFIX "mirror log" static LIST_HEAD(_log_types); static DEFINE_SPINLOCK(_lock); int dm_register_dirty_log_type(struct dirty_log_type *type) { spin_lock(&_lock); type->use_count = 0; list_add(&type->list, &_log_types); spin_unlock(&_lock); return 0; } int dm_unregister_dirty_log_type(struct dirty_log_type *type) { spin_lock(&_lock); if (type->use_count) DMWARN("Attempt to unregister a log type that is still in use"); else list_del(&type->list); spin_unlock(&_lock); return 0; } static struct dirty_log_type *get_type(const char *type_name) { struct dirty_log_type *type; spin_lock(&_lock); list_for_each_entry (type, &_log_types, list) if (!strcmp(type_name, type->name)) { if (!type->use_count && !try_module_get(type->module)){ spin_unlock(&_lock); return NULL; } type->use_count++; spin_unlock(&_lock); return type; } spin_unlock(&_lock); return NULL; } static void put_type(struct dirty_log_type *type) { spin_lock(&_lock); if (!--type->use_count) module_put(type->module); spin_unlock(&_lock); } struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti, unsigned int argc, char **argv) { struct dirty_log_type *type; struct dirty_log *log; log = kmalloc(sizeof(*log), GFP_KERNEL); if (!log) return NULL; type = get_type(type_name); if (!type) { kfree(log); return NULL; } log->type = type; if (type->ctr(log, ti, argc, argv)) { kfree(log); put_type(type); return NULL; } return log; } void dm_destroy_dirty_log(struct dirty_log *log) { log->type->dtr(log); put_type(log->type); kfree(log); } /*----------------------------------------------------------------- * Persistent and core logs share a lot of their implementation. * FIXME: need a reload method to be called from a resume *---------------------------------------------------------------*/ /* * Magic for persistent mirrors: "MiRr" */ #define MIRROR_MAGIC 0x4D695272 /* * The on-disk version of the metadata. */ #define MIRROR_DISK_VERSION 2 #define LOG_OFFSET 2 struct log_header { uint32_t magic; /* * Simple, incrementing version. no backward * compatibility. */ uint32_t version; sector_t nr_regions; }; struct log_c { struct dm_target *ti; int touched; uint32_t region_size; unsigned int region_count; region_t sync_count; unsigned bitset_uint32_count; uint32_t *clean_bits; uint32_t *sync_bits; uint32_t *recovering_bits; /* FIXME: this seems excessive */ int sync_search; /* Resync flag */ enum sync { DEFAULTSYNC, /* Synchronize if necessary */ NOSYNC, /* Devices known to be already in sync */ FORCESYNC, /* Force a sync to happen */ } sync; /* * Disk log fields */ struct dm_dev *log_dev; struct log_header header; struct io_region header_location; struct log_header *disk_header; }; /* * The touched member needs to be updated every time we access * one of the bitsets. */ static inline int log_test_bit(uint32_t *bs, unsigned bit) { return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0; } static inline void log_set_bit(struct log_c *l, uint32_t *bs, unsigned bit) { ext2_set_bit(bit, (unsigned long *) bs); l->touched = 1; } static inline void log_clear_bit(struct log_c *l, uint32_t *bs, unsigned bit) { ext2_clear_bit(bit, (unsigned long *) bs); l->touched = 1; } /*---------------------------------------------------------------- * Header IO *--------------------------------------------------------------*/ static void header_to_disk(struct log_header *core, struct log_header *disk) { disk->magic = cpu_to_le32(core->magic); disk->version = cpu_to_le32(core->version); disk->nr_regions = cpu_to_le64(core->nr_regions); } static void header_from_disk(struct log_header *core, struct log_header *disk) { core->magic = le32_to_cpu(disk->magic); core->version = le32_to_cpu(disk->version); core->nr_regions = le64_to_cpu(disk->nr_regions); } static int read_header(struct log_c *log) { int r; unsigned long ebits; r = dm_io_sync_vm(1, &log->header_location, READ, log->disk_header, &ebits); if (r) return r; header_from_disk(&log->header, log->disk_header); /* New log required? */ if (log->sync != DEFAULTSYNC || log->header.magic != MIRROR_MAGIC) { log->header.magic = MIRROR_MAGIC; log->header.version = MIRROR_DISK_VERSION; log->header.nr_regions = 0; } #ifdef __LITTLE_ENDIAN if (log->header.version == 1) log->header.version = 2; #endif if (log->header.version != MIRROR_DISK_VERSION) { DMWARN("incompatible disk log version"); return -EINVAL; } return 0; } static inline int write_header(struct log_c *log) { unsigned long ebits; header_to_disk(&log->header, log->disk_header); return dm_io_sync_vm(1, &log->header_location, WRITE, log->disk_header, &ebits); } /*---------------------------------------------------------------- * core log constructor/destructor * * argv contains region_size followed optionally by [no]sync *--------------------------------------------------------------*/ #define BYTE_SHIFT 3 static int create_log_context(struct dirty_log *log, struct dm_target *ti, unsigned int argc, char **argv, struct dm_dev *dev) { enum sync sync = DEFAULTSYNC; struct log_c *lc; uint32_t region_size; unsigned int region_count; size_t bitset_size, buf_size; if (argc < 1 || argc > 2) { DMWARN("wrong number of arguments to mirror log"); return -EINVAL; } if (argc > 1) { if (!strcmp(argv[1], "sync")) sync = FORCESYNC; else if (!strcmp(argv[1], "nosync")) sync = NOSYNC; else { DMWARN("unrecognised sync argument to mirror log: %s", argv[1]); return -EINVAL; } } if (sscanf(argv[0], "%u", ®ion_size) != 1) { DMWARN("invalid region size string"); return -EINVAL; } region_count = dm_sector_div_up(ti->len, region_size); lc = kmalloc(sizeof(*lc), GFP_KERNEL); if (!lc) { DMWARN("couldn't allocate core log"); return -ENOMEM; } lc->ti = ti; lc->touched = 0; lc->region_size = region_size; lc->region_count = region_count; lc->sync = sync; /* * Work out how many "unsigned long"s we need to hold the bitset. */ bitset_size = dm_round_up(region_count, sizeof(*lc->clean_bits) << BYTE_SHIFT); bitset_size >>= BYTE_SHIFT; lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits); /* * Disk log? */ if (!dev) { lc->clean_bits = vmalloc(bitset_size); if (!lc->clean_bits) { DMWARN("couldn't allocate clean bitset"); kfree(lc); return -ENOMEM; } lc->disk_header = NULL; } else { lc->log_dev = dev; lc->header_location.bdev = lc->log_dev->bdev; lc->header_location.sector = 0; /* * Buffer holds both header and bitset. */ buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size, ti->limits.hardsect_size); lc->header_location.count = buf_size >> SECTOR_SHIFT; lc->disk_header = vmalloc(buf_size); if (!lc->disk_header) { DMWARN("couldn't allocate disk log buffer"); kfree(lc); return -ENOMEM; } lc->clean_bits = (void *)lc->disk_header + (LOG_OFFSET << SECTOR_SHIFT); } memset(lc->clean_bits, -1, bitset_size); lc->sync_bits = vmalloc(bitset_size); if (!lc->sync_bits) { DMWARN("couldn't allocate sync bitset"); if (!dev) vfree(lc->clean_bits); vfree(lc->disk_header); kfree(lc); return -ENOMEM; } memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size); lc->sync_count = (sync == NOSYNC) ? region_count : 0; lc->recovering_bits = vmalloc(bitset_size); if (!lc->recovering_bits) { DMWARN("couldn't allocate sync bitset"); vfree(lc->sync_bits); if (!dev) vfree(lc->clean_bits); vfree(lc->disk_header); kfree(lc); return -ENOMEM; } memset(lc->recovering_bits, 0, bitset_size); lc->sync_search = 0; log->context = lc; return 0; } static int core_ctr(struct dirty_log *log, struct dm_target *ti, unsigned int argc, char **argv) { return create_log_context(log, ti, argc, argv, NULL); } static void destroy_log_context(struct log_c *lc) { vfree(lc->sync_bits); vfree(lc->recovering_bits); kfree(lc); } static void core_dtr(struct dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; vfree(lc->clean_bits); destroy_log_context(lc); } /*---------------------------------------------------------------- * disk log constructor/destructor * * argv contains log_device region_size followed optionally by [no]sync *--------------------------------------------------------------*/ static int disk_ctr(struct dirty_log *log, struct dm_target *ti, unsigned int argc, char **argv) { int r; struct dm_dev *dev; if (argc < 2 || argc > 3) { DMWARN("wrong number of arguments to disk mirror log"); return -EINVAL; } r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */, FMODE_READ | FMODE_WRITE, &dev); if (r) return r; r = create_log_context(log, ti, argc - 1, argv + 1, dev); if (r) { dm_put_device(ti, dev); return r; } return 0; } static void disk_dtr(struct dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; dm_put_device(lc->ti, lc->log_dev); vfree(lc->disk_header); destroy_log_context(lc); } static int count_bits32(uint32_t *addr, unsigned size) { int count = 0, i; for (i = 0; i < size; i++) { count += hweight32(*(addr+i)); } return count; } static int disk_resume(struct dirty_log *log) { int r; unsigned i; struct log_c *lc = (struct log_c *) log->context; size_t size = lc->bitset_uint32_count * sizeof(uint32_t); /* read the disk header */ r = read_header(lc); if (r) return r; /* set or clear any new bits -- device has grown */ if (lc->sync == NOSYNC) for (i = lc->header.nr_regions; i < lc->region_count; i++) /* FIXME: amazingly inefficient */ log_set_bit(lc, lc->clean_bits, i); else for (i = lc->header.nr_regions; i < lc->region_count; i++) /* FIXME: amazingly inefficient */ log_clear_bit(lc, lc->clean_bits, i); /* clear any old bits -- device has shrunk */ for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++) log_clear_bit(lc, lc->clean_bits, i); /* copy clean across to sync */ memcpy(lc->sync_bits, lc->clean_bits, size); lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count); /* set the correct number of regions in the header */ lc->header.nr_regions = lc->region_count; /* write the new header */ return write_header(lc); } static uint32_t core_get_region_size(struct dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; return lc->region_size; } static int core_is_clean(struct dirty_log *log, region_t region) { struct log_c *lc = (struct log_c *) log->context; return log_test_bit(lc->clean_bits, region); } static int core_in_sync(struct dirty_log *log, region_t region, int block) { struct log_c *lc = (struct log_c *) log->context; return log_test_bit(lc->sync_bits, region); } static int core_flush(struct dirty_log *log) { /* no op */ return 0; } static int disk_flush(struct dirty_log *log) { int r; struct log_c *lc = (struct log_c *) log->context; /* only write if the log has changed */ if (!lc->touched) return 0; r = write_header(lc); if (!r) lc->touched = 0; return r; } static void core_mark_region(struct dirty_log *log, region_t region) { struct log_c *lc = (struct log_c *) log->context; log_clear_bit(lc, lc->clean_bits, region); } static void core_clear_region(struct dirty_log *log, region_t region) { struct log_c *lc = (struct log_c *) log->context; log_set_bit(lc, lc->clean_bits, region); } static int core_get_resync_work(struct dirty_log *log, region_t *region) { struct log_c *lc = (struct log_c *) log->context; if (lc->sync_search >= lc->region_count) return 0; do { *region = ext2_find_next_zero_bit( (unsigned long *) lc->sync_bits, lc->region_count, lc->sync_search); lc->sync_search = *region + 1; if (*region >= lc->region_count) return 0; } while (log_test_bit(lc->recovering_bits, *region)); log_set_bit(lc, lc->recovering_bits, *region); return 1; } static void core_complete_resync_work(struct dirty_log *log, region_t region, int success) { struct log_c *lc = (struct log_c *) log->context; log_clear_bit(lc, lc->recovering_bits, region); if (success) { log_set_bit(lc, lc->sync_bits, region); lc->sync_count++; } } static region_t core_get_sync_count(struct dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; return lc->sync_count; } #define DMEMIT_SYNC \ if (lc->sync != DEFAULTSYNC) \ DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "") static int core_status(struct dirty_log *log, status_type_t status, char *result, unsigned int maxlen) { int sz = 0; struct log_c *lc = log->context; switch(status) { case STATUSTYPE_INFO: break; case STATUSTYPE_TABLE: DMEMIT("%s %u %u ", log->type->name, lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size); DMEMIT_SYNC; } return sz; } static int disk_status(struct dirty_log *log, status_type_t status, char *result, unsigned int maxlen) { int sz = 0; char buffer[16]; struct log_c *lc = log->context; switch(status) { case STATUSTYPE_INFO: break; case STATUSTYPE_TABLE: format_dev_t(buffer, lc->log_dev->bdev->bd_dev); DMEMIT("%s %u %s %u ", log->type->name, lc->sync == DEFAULTSYNC ? 2 : 3, buffer, lc->region_size); DMEMIT_SYNC; } return sz; } static struct dirty_log_type _core_type = { .name = "core", .module = THIS_MODULE, .ctr = core_ctr, .dtr = core_dtr, .get_region_size = core_get_region_size, .is_clean = core_is_clean, .in_sync = core_in_sync, .flush = core_flush, .mark_region = core_mark_region, .clear_region = core_clear_region, .get_resync_work = core_get_resync_work, .complete_resync_work = core_complete_resync_work, .get_sync_count = core_get_sync_count, .status = core_status, }; static struct dirty_log_type _disk_type = { .name = "disk", .module = THIS_MODULE, .ctr = disk_ctr, .dtr = disk_dtr, .suspend = disk_flush, .resume = disk_resume, .get_region_size = core_get_region_size, .is_clean = core_is_clean, .in_sync = core_in_sync, .flush = disk_flush, .mark_region = core_mark_region, .clear_region = core_clear_region, .get_resync_work = core_get_resync_work, .complete_resync_work = core_complete_resync_work, .get_sync_count = core_get_sync_count, .status = disk_status, }; int __init dm_dirty_log_init(void) { int r; r = dm_register_dirty_log_type(&_core_type); if (r) DMWARN("couldn't register core log"); r = dm_register_dirty_log_type(&_disk_type); if (r) { DMWARN("couldn't register disk type"); dm_unregister_dirty_log_type(&_core_type); } return r; } void dm_dirty_log_exit(void) { dm_unregister_dirty_log_type(&_disk_type); dm_unregister_dirty_log_type(&_core_type); } EXPORT_SYMBOL(dm_register_dirty_log_type); EXPORT_SYMBOL(dm_unregister_dirty_log_type); EXPORT_SYMBOL(dm_create_dirty_log); EXPORT_SYMBOL(dm_destroy_dirty_log);