/* * Copyright (C) 2003 Sistina Software * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the LGPL. */ #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/vmalloc.h> #include <linux/dm-io.h> #include <linux/dm-dirty-log.h> #include <linux/device-mapper.h> #define DM_MSG_PREFIX "dirty region log" static LIST_HEAD(_log_types); static DEFINE_SPINLOCK(_lock); static struct dm_dirty_log_type *__find_dirty_log_type(const char *name) { struct dm_dirty_log_type *log_type; list_for_each_entry(log_type, &_log_types, list) if (!strcmp(name, log_type->name)) return log_type; return NULL; } static struct dm_dirty_log_type *_get_dirty_log_type(const char *name) { struct dm_dirty_log_type *log_type; spin_lock(&_lock); log_type = __find_dirty_log_type(name); if (log_type && !try_module_get(log_type->module)) log_type = NULL; spin_unlock(&_lock); return log_type; } /* * get_type * @type_name * * Attempt to retrieve the dm_dirty_log_type by name. If not already * available, attempt to load the appropriate module. * * Log modules are named "dm-log-" followed by the 'type_name'. * Modules may contain multiple types. * This function will first try the module "dm-log-<type_name>", * then truncate 'type_name' on the last '-' and try again. * * For example, if type_name was "clustered-disk", it would search * 'dm-log-clustered-disk' then 'dm-log-clustered'. * * Returns: dirty_log_type* on success, NULL on failure */ static struct dm_dirty_log_type *get_type(const char *type_name) { char *p, *type_name_dup; struct dm_dirty_log_type *log_type; if (!type_name) return NULL; log_type = _get_dirty_log_type(type_name); if (log_type) return log_type; type_name_dup = kstrdup(type_name, GFP_KERNEL); if (!type_name_dup) { DMWARN("No memory left to attempt log module load for \"%s\"", type_name); return NULL; } while (request_module("dm-log-%s", type_name_dup) || !(log_type = _get_dirty_log_type(type_name))) { p = strrchr(type_name_dup, '-'); if (!p) break; p[0] = '\0'; } if (!log_type) DMWARN("Module for logging type \"%s\" not found.", type_name); kfree(type_name_dup); return log_type; } static void put_type(struct dm_dirty_log_type *type) { if (!type) return; spin_lock(&_lock); if (!__find_dirty_log_type(type->name)) goto out; module_put(type->module); out: spin_unlock(&_lock); } int dm_dirty_log_type_register(struct dm_dirty_log_type *type) { int r = 0; spin_lock(&_lock); if (!__find_dirty_log_type(type->name)) list_add(&type->list, &_log_types); else r = -EEXIST; spin_unlock(&_lock); return r; } EXPORT_SYMBOL(dm_dirty_log_type_register); int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type) { spin_lock(&_lock); if (!__find_dirty_log_type(type->name)) { spin_unlock(&_lock); return -EINVAL; } list_del(&type->list); spin_unlock(&_lock); return 0; } EXPORT_SYMBOL(dm_dirty_log_type_unregister); struct dm_dirty_log *dm_dirty_log_create(const char *type_name, struct dm_target *ti, int (*flush_callback_fn)(struct dm_target *ti), unsigned int argc, char **argv) { struct dm_dirty_log_type *type; struct dm_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->flush_callback_fn = flush_callback_fn; log->type = type; if (type->ctr(log, ti, argc, argv)) { kfree(log); put_type(type); return NULL; } return log; } EXPORT_SYMBOL(dm_dirty_log_create); void dm_dirty_log_destroy(struct dm_dirty_log *log) { log->type->dtr(log); put_type(log->type); kfree(log); } EXPORT_SYMBOL(dm_dirty_log_destroy); /*----------------------------------------------------------------- * 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_disk { __le32 magic; /* * Simple, incrementing version. no backward * compatibility. */ __le32 version; __le64 nr_regions; } __packed; struct log_header_core { uint32_t magic; uint32_t version; uint64_t nr_regions; }; struct log_c { struct dm_target *ti; int touched_dirtied; int touched_cleaned; int flush_failed; 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; struct dm_io_request io_req; /* * Disk log fields */ int log_dev_failed; int log_dev_flush_failed; struct dm_dev *log_dev; struct log_header_core header; struct dm_io_region header_location; struct log_header_disk *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 test_bit_le(bit, bs) ? 1 : 0; } static inline void log_set_bit(struct log_c *l, uint32_t *bs, unsigned bit) { __set_bit_le(bit, bs); l->touched_cleaned = 1; } static inline void log_clear_bit(struct log_c *l, uint32_t *bs, unsigned bit) { __clear_bit_le(bit, bs); l->touched_dirtied = 1; } /*---------------------------------------------------------------- * Header IO *--------------------------------------------------------------*/ static void header_to_disk(struct log_header_core *core, struct log_header_disk *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 *core, struct log_header_disk *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 rw_header(struct log_c *lc, int op) { lc->io_req.bi_op = op; lc->io_req.bi_op_flags = 0; return dm_io(&lc->io_req, 1, &lc->header_location, NULL); } static int flush_header(struct log_c *lc) { struct dm_io_region null_location = { .bdev = lc->header_location.bdev, .sector = 0, .count = 0, }; lc->io_req.bi_op = REQ_OP_WRITE; lc->io_req.bi_op_flags = REQ_PREFLUSH; return dm_io(&lc->io_req, 1, &null_location, NULL); } static int read_header(struct log_c *log) { int r; r = rw_header(log, REQ_OP_READ); 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 int _check_region_size(struct dm_target *ti, uint32_t region_size) { if (region_size < 2 || region_size > ti->len) return 0; if (!is_power_of_2(region_size)) return 0; return 1; } /*---------------------------------------------------------------- * core log constructor/destructor * * argv contains region_size followed optionally by [no]sync *--------------------------------------------------------------*/ #define BYTE_SHIFT 3 static int create_log_context(struct dm_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; int r; char dummy; if (argc < 1 || argc > 2) { DMWARN("wrong number of arguments to dirty region 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 " "dirty region log: %s", argv[1]); return -EINVAL; } } if (sscanf(argv[0], "%u%c", ®ion_size, &dummy) != 1 || !_check_region_size(ti, region_size)) { DMWARN("invalid region size %s", argv[0]); 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_dirtied = 0; lc->touched_cleaned = 0; lc->flush_failed = 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->log_dev_failed = 0; lc->log_dev_flush_failed = 0; 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, bdev_logical_block_size(lc->header_location. bdev)); if (buf_size > i_size_read(dev->bdev->bd_inode)) { DMWARN("log device %s too small: need %llu bytes", dev->name, (unsigned long long)buf_size); kfree(lc); return -EINVAL; } lc->header_location.count = buf_size >> SECTOR_SHIFT; lc->io_req.mem.type = DM_IO_VMA; lc->io_req.notify.fn = NULL; lc->io_req.client = dm_io_client_create(); if (IS_ERR(lc->io_req.client)) { r = PTR_ERR(lc->io_req.client); DMWARN("couldn't allocate disk io client"); kfree(lc); return r; } lc->disk_header = vmalloc(buf_size); if (!lc->disk_header) { DMWARN("couldn't allocate disk log buffer"); dm_io_client_destroy(lc->io_req.client); kfree(lc); return -ENOMEM; } lc->io_req.mem.ptr.vma = lc->disk_header; 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); else dm_io_client_destroy(lc->io_req.client); 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 = vzalloc(bitset_size); if (!lc->recovering_bits) { DMWARN("couldn't allocate sync bitset"); vfree(lc->sync_bits); if (!dev) vfree(lc->clean_bits); else dm_io_client_destroy(lc->io_req.client); vfree(lc->disk_header); kfree(lc); return -ENOMEM; } lc->sync_search = 0; log->context = lc; return 0; } static int core_ctr(struct dm_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 dm_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 dm_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 dirty region log"); return -EINVAL; } r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &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 dm_dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; dm_put_device(lc->ti, lc->log_dev); vfree(lc->disk_header); dm_io_client_destroy(lc->io_req.client); destroy_log_context(lc); } static void fail_log_device(struct log_c *lc) { if (lc->log_dev_failed) return; lc->log_dev_failed = 1; dm_table_event(lc->ti->table); } static int disk_resume(struct dm_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) { DMWARN("%s: Failed to read header on dirty region log device", lc->log_dev->name); fail_log_device(lc); /* * If the log device cannot be read, we must assume * all regions are out-of-sync. If we simply return * here, the state will be uninitialized and could * lead us to return 'in-sync' status for regions * that are actually 'out-of-sync'. */ lc->header.nr_regions = 0; } /* 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 = memweight(lc->clean_bits, lc->bitset_uint32_count * sizeof(uint32_t)); lc->sync_search = 0; /* set the correct number of regions in the header */ lc->header.nr_regions = lc->region_count; header_to_disk(&lc->header, lc->disk_header); /* write the new header */ r = rw_header(lc, REQ_OP_WRITE); if (!r) { r = flush_header(lc); if (r) lc->log_dev_flush_failed = 1; } if (r) { DMWARN("%s: Failed to write header on dirty region log device", lc->log_dev->name); fail_log_device(lc); } return r; } static uint32_t core_get_region_size(struct dm_dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; return lc->region_size; } static int core_resume(struct dm_dirty_log *log) { struct log_c *lc = (struct log_c *) log->context; lc->sync_search = 0; return 0; } static int core_is_clean(struct dm_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 dm_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 dm_dirty_log *log) { /* no op */ return 0; } static int disk_flush(struct dm_dirty_log *log) { int r, i; struct log_c *lc = log->context; /* only write if the log has changed */ if (!lc->touched_cleaned && !lc->touched_dirtied) return 0; if (lc->touched_cleaned && log->flush_callback_fn && log->flush_callback_fn(lc->ti)) { /* * At this point it is impossible to determine which * regions are clean and which are dirty (without * re-reading the log off disk). So mark all of them * dirty. */ lc->flush_failed = 1; for (i = 0; i < lc->region_count; i++) log_clear_bit(lc, lc->clean_bits, i); } r = rw_header(lc, REQ_OP_WRITE); if (r) fail_log_device(lc); else { if (lc->touched_dirtied) { r = flush_header(lc); if (r) { lc->log_dev_flush_failed = 1; fail_log_device(lc); } else lc->touched_dirtied = 0; } lc->touched_cleaned = 0; } return r; } static void core_mark_region(struct dm_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 dm_dirty_log *log, region_t region) { struct log_c *lc = (struct log_c *) log->context; if (likely(!lc->flush_failed)) log_set_bit(lc, lc->clean_bits, region); } static int core_get_resync_work(struct dm_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 = find_next_zero_bit_le(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_set_region_sync(struct dm_dirty_log *log, region_t region, int in_sync) { struct log_c *lc = (struct log_c *) log->context; log_clear_bit(lc, lc->recovering_bits, region); if (in_sync) { log_set_bit(lc, lc->sync_bits, region); lc->sync_count++; } else if (log_test_bit(lc->sync_bits, region)) { lc->sync_count--; log_clear_bit(lc, lc->sync_bits, region); } } static region_t core_get_sync_count(struct dm_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 dm_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: DMEMIT("1 %s", log->type->name); 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 dm_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: DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name, lc->log_dev_flush_failed ? 'F' : lc->log_dev_failed ? 'D' : 'A'); break; case STATUSTYPE_TABLE: DMEMIT("%s %u %s %u ", log->type->name, lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name, lc->region_size); DMEMIT_SYNC; } return sz; } static struct dm_dirty_log_type _core_type = { .name = "core", .module = THIS_MODULE, .ctr = core_ctr, .dtr = core_dtr, .resume = core_resume, .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, .set_region_sync = core_set_region_sync, .get_sync_count = core_get_sync_count, .status = core_status, }; static struct dm_dirty_log_type _disk_type = { .name = "disk", .module = THIS_MODULE, .ctr = disk_ctr, .dtr = disk_dtr, .postsuspend = 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, .set_region_sync = core_set_region_sync, .get_sync_count = core_get_sync_count, .status = disk_status, }; static int __init dm_dirty_log_init(void) { int r; r = dm_dirty_log_type_register(&_core_type); if (r) DMWARN("couldn't register core log"); r = dm_dirty_log_type_register(&_disk_type); if (r) { DMWARN("couldn't register disk type"); dm_dirty_log_type_unregister(&_core_type); } return r; } static void __exit dm_dirty_log_exit(void) { dm_dirty_log_type_unregister(&_disk_type); dm_dirty_log_type_unregister(&_core_type); } module_init(dm_dirty_log_init); module_exit(dm_dirty_log_exit); MODULE_DESCRIPTION(DM_NAME " dirty region log"); MODULE_AUTHOR("Joe Thornber, Heinz Mauelshagen <dm-devel@redhat.com>"); MODULE_LICENSE("GPL");