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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [md/] [dm-log.c] - Blame information for rev 62

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/*
 * 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;
 
        struct dm_io_request io_req;
 
        /*
         * Disk log fields
         */
        int log_dev_failed;
        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 rw_header(struct log_c *lc, int rw)
{
        lc->io_req.bi_rw = rw;
        lc->io_req.mem.ptr.vma = lc->disk_header;
        lc->io_req.notify.fn = NULL;
 
        return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
}
 
static int read_header(struct log_c *log)
{
        int r;
 
        r = rw_header(log, 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 inline int write_header(struct log_c *log)
{
        header_to_disk(&log->header, log->disk_header);
        return rw_header(log, WRITE);
}
 
/*----------------------------------------------------------------
 * 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;
        int r;
 
        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", &region_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->log_dev_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, ti->limits.hardsect_size);
                lc->header_location.count = buf_size >> SECTOR_SHIFT;
                lc->io_req.mem.type = DM_IO_VMA;
                lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
                                                                   PAGE_SIZE));
                if (IS_ERR(lc->io_req.client)) {
                        r = PTR_ERR(lc->io_req.client);
                        DMWARN("couldn't allocate disk io client");
                        kfree(lc);
                        return -ENOMEM;
                }
 
                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);
        dm_io_client_destroy(lc->io_req.client);
        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 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 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 mirror 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 = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
        lc->sync_search = 0;
 
        /* set the correct number of regions in the header */
        lc->header.nr_regions = lc->region_count;
 
        /* write the new header */
        r = write_header(lc);
        if (r) {
                DMWARN("%s: Failed to write header on mirror log device",
                       lc->log_dev->name);
                fail_log_device(lc);
        }
 
        return r;
}
 
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_resume(struct dirty_log *log)
{
        struct log_c *lc = (struct log_c *) log->context;
        lc->sync_search = 0;
        return 0;
}
 
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)
                fail_log_device(lc);
        else
                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_set_region_sync(struct 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 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:
                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 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_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 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 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,
};
 
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);

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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [md/] [dm-log.c] - Blame information for rev 62

Line No.	Rev	Author	Line
1	62	marcus.erl	`/*`
2			`* Copyright (C) 2003 Sistina Software`
3			`*`
4			`* This file is released under the LGPL.`
5			`*/`
6
7			`#include <linux/init.h>`
8			`#include <linux/slab.h>`
9			`#include <linux/module.h>`
10			`#include <linux/vmalloc.h>`
11
12			`#include "dm-log.h"`
13			`#include "dm-io.h"`
14
15			`#define DM_MSG_PREFIX "mirror log"`
16
17			`static LIST_HEAD(_log_types);`
18			`static DEFINE_SPINLOCK(_lock);`
19
20			`int dm_register_dirty_log_type(struct dirty_log_type *type)`
21			`{`
22			`spin_lock(&_lock);`
23			`type->use_count = 0;`
24			`list_add(&type->list, &_log_types);`
25			`spin_unlock(&_lock);`
26
27			`return 0;`
28			`}`
29
30			`int dm_unregister_dirty_log_type(struct dirty_log_type *type)`
31			`{`
32			`spin_lock(&_lock);`
33
34			`if (type->use_count)`
35			`DMWARN("Attempt to unregister a log type that is still in use");`
36			`else`
37			`list_del(&type->list);`
38
39			`spin_unlock(&_lock);`
40
41			`return 0;`
42			`}`
43
44			`static struct dirty_log_type get_type(const char type_name)`
45			`{`
46			`struct dirty_log_type *type;`
47
48			`spin_lock(&_lock);`
49			`list_for_each_entry (type, &_log_types, list)`
50			`if (!strcmp(type_name, type->name)) {`
51			`if (!type->use_count && !try_module_get(type->module)){`
52			`spin_unlock(&_lock);`
53			`return NULL;`
54			`}`
55			`type->use_count++;`
56			`spin_unlock(&_lock);`
57			`return type;`
58			`}`
59
60			`spin_unlock(&_lock);`
61			`return NULL;`
62			`}`
63
64			`static void put_type(struct dirty_log_type *type)`
65			`{`
66			`spin_lock(&_lock);`
67			`if (!--type->use_count)`
68			`module_put(type->module);`
69			`spin_unlock(&_lock);`
70			`}`
71
72			`struct dirty_log dm_create_dirty_log(const char type_name, struct dm_target *ti,`
73			`unsigned int argc, char **argv)`
74			`{`
75			`struct dirty_log_type *type;`
76			`struct dirty_log *log;`
77
78			`log = kmalloc(sizeof(*log), GFP_KERNEL);`
79			`if (!log)`
80			`return NULL;`
81
82			`type = get_type(type_name);`
83			`if (!type) {`
84			`kfree(log);`
85			`return NULL;`
86			`}`
87
88			`log->type = type;`
89			`if (type->ctr(log, ti, argc, argv)) {`
90			`kfree(log);`
91			`put_type(type);`
92			`return NULL;`
93			`}`
94
95			`return log;`
96			`}`
97
98			`void dm_destroy_dirty_log(struct dirty_log *log)`
99			`{`
100			`log->type->dtr(log);`
101			`put_type(log->type);`
102			`kfree(log);`
103			`}`
104
105			`/*-----------------------------------------------------------------`
106			`* Persistent and core logs share a lot of their implementation.`
107			`* FIXME: need a reload method to be called from a resume`
108			`---------------------------------------------------------------/`
109			`/*`
110			`* Magic for persistent mirrors: "MiRr"`
111			`*/`
112			`#define MIRROR_MAGIC 0x4D695272`
113
114			`/*`
115			`* The on-disk version of the metadata.`
116			`*/`
117			`#define MIRROR_DISK_VERSION 2`
118			`#define LOG_OFFSET 2`
119
120			`struct log_header {`
121			`uint32_t magic;`
122
123			`/*`
124			`* Simple, incrementing version. no backward`
125			`* compatibility.`
126			`*/`
127			`uint32_t version;`
128			`sector_t nr_regions;`
129			`};`
130
131			`struct log_c {`
132			`struct dm_target *ti;`
133			`int touched;`
134			`uint32_t region_size;`
135			`unsigned int region_count;`
136			`region_t sync_count;`
137
138			`unsigned bitset_uint32_count;`
139			`uint32_t *clean_bits;`
140			`uint32_t *sync_bits;`
141			`uint32_t recovering_bits; / FIXME: this seems excessive */`
142
143			`int sync_search;`
144
145			`/* Resync flag */`
146			`enum sync {`
147			`DEFAULTSYNC, /* Synchronize if necessary */`
148			`NOSYNC, /* Devices known to be already in sync */`
149			`FORCESYNC, /* Force a sync to happen */`
150			`} sync;`
151
152			`struct dm_io_request io_req;`
153
154			`/*`
155			`* Disk log fields`
156			`*/`
157			`int log_dev_failed;`
158			`struct dm_dev *log_dev;`
159			`struct log_header header;`
160
161			`struct io_region header_location;`
162			`struct log_header *disk_header;`
163			`};`
164
165			`/*`
166			`* The touched member needs to be updated every time we access`
167			`* one of the bitsets.`
168			`*/`
169			`static inline int log_test_bit(uint32_t *bs, unsigned bit)`
170			`{`
171			`return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;`
172			`}`
173
174			`static inline void log_set_bit(struct log_c *l,`
175			`uint32_t *bs, unsigned bit)`
176			`{`
177			`ext2_set_bit(bit, (unsigned long *) bs);`
178			`l->touched = 1;`
179			`}`
180
181			`static inline void log_clear_bit(struct log_c *l,`
182			`uint32_t *bs, unsigned bit)`
183			`{`
184			`ext2_clear_bit(bit, (unsigned long *) bs);`
185			`l->touched = 1;`
186			`}`
187
188			`/*----------------------------------------------------------------`
189			`* Header IO`
190			`--------------------------------------------------------------/`
191			`static void header_to_disk(struct log_header core, struct log_header disk)`
192			`{`
193			`disk->magic = cpu_to_le32(core->magic);`
194			`disk->version = cpu_to_le32(core->version);`
195			`disk->nr_regions = cpu_to_le64(core->nr_regions);`
196			`}`
197
198			`static void header_from_disk(struct log_header core, struct log_header disk)`
199			`{`
200			`core->magic = le32_to_cpu(disk->magic);`
201			`core->version = le32_to_cpu(disk->version);`
202			`core->nr_regions = le64_to_cpu(disk->nr_regions);`
203			`}`
204
205			`static int rw_header(struct log_c *lc, int rw)`
206			`{`
207			`lc->io_req.bi_rw = rw;`
208			`lc->io_req.mem.ptr.vma = lc->disk_header;`
209			`lc->io_req.notify.fn = NULL;`
210
211			`return dm_io(&lc->io_req, 1, &lc->header_location, NULL);`
212			`}`
213
214			`static int read_header(struct log_c *log)`
215			`{`
216			`int r;`
217
218			`r = rw_header(log, READ);`
219			`if (r)`
220			`return r;`
221
222			`header_from_disk(&log->header, log->disk_header);`
223
224			`/* New log required? */`
225			`if (log->sync != DEFAULTSYNC \|\| log->header.magic != MIRROR_MAGIC) {`
226			`log->header.magic = MIRROR_MAGIC;`
227			`log->header.version = MIRROR_DISK_VERSION;`
228			`log->header.nr_regions = 0;`
229			`}`
230
231			`#ifdef __LITTLE_ENDIAN`
232			`if (log->header.version == 1)`
233			`log->header.version = 2;`
234			`#endif`
235
236			`if (log->header.version != MIRROR_DISK_VERSION) {`
237			`DMWARN("incompatible disk log version");`
238			`return -EINVAL;`
239			`}`
240
241			`return 0;`
242			`}`
243
244			`static inline int write_header(struct log_c *log)`
245			`{`
246			`header_to_disk(&log->header, log->disk_header);`
247			`return rw_header(log, WRITE);`
248			`}`
249
250			`/*----------------------------------------------------------------`
251			`* core log constructor/destructor`
252			`*`
253			`* argv contains region_size followed optionally by [no]sync`
254			`--------------------------------------------------------------/`
255			`#define BYTE_SHIFT 3`
256			`static int create_log_context(struct dirty_log log, struct dm_target ti,`
257			`unsigned int argc, char **argv,`
258			`struct dm_dev *dev)`
259			`{`
260			`enum sync sync = DEFAULTSYNC;`
261
262			`struct log_c *lc;`
263			`uint32_t region_size;`
264			`unsigned int region_count;`
265			`size_t bitset_size, buf_size;`
266			`int r;`
267
268			`if (argc < 1 \|\| argc > 2) {`
269			`DMWARN("wrong number of arguments to mirror log");`
270			`return -EINVAL;`
271			`}`
272
273			`if (argc > 1) {`
274			`if (!strcmp(argv[1], "sync"))`
275			`sync = FORCESYNC;`
276			`else if (!strcmp(argv[1], "nosync"))`
277			`sync = NOSYNC;`
278			`else {`
279			`DMWARN("unrecognised sync argument to mirror log: %s",`
280			`argv[1]);`
281			`return -EINVAL;`
282			`}`
283			`}`
284
285			`if (sscanf(argv[0], "%u", &region_size) != 1) {`
286			`DMWARN("invalid region size string");`
287			`return -EINVAL;`
288			`}`
289
290			`region_count = dm_sector_div_up(ti->len, region_size);`
291
292			`lc = kmalloc(sizeof(*lc), GFP_KERNEL);`
293			`if (!lc) {`
294			`DMWARN("couldn't allocate core log");`
295			`return -ENOMEM;`
296			`}`
297
298			`lc->ti = ti;`
299			`lc->touched = 0;`
300			`lc->region_size = region_size;`
301			`lc->region_count = region_count;`
302			`lc->sync = sync;`
303
304			`/*`
305			`* Work out how many "unsigned long"s we need to hold the bitset.`
306			`*/`
307			`bitset_size = dm_round_up(region_count,`
308			`sizeof(*lc->clean_bits) << BYTE_SHIFT);`
309			`bitset_size >>= BYTE_SHIFT;`
310
311			`lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);`
312
313			`/*`
314			`* Disk log?`
315			`*/`
316			`if (!dev) {`
317			`lc->clean_bits = vmalloc(bitset_size);`
318			`if (!lc->clean_bits) {`
319			`DMWARN("couldn't allocate clean bitset");`
320			`kfree(lc);`
321			`return -ENOMEM;`
322			`}`
323			`lc->disk_header = NULL;`
324			`} else {`
325			`lc->log_dev = dev;`
326			`lc->log_dev_failed = 0;`
327			`lc->header_location.bdev = lc->log_dev->bdev;`
328			`lc->header_location.sector = 0;`
329
330			`/*`
331			`* Buffer holds both header and bitset.`
332			`*/`
333			`buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +`
334			`bitset_size, ti->limits.hardsect_size);`
335			`lc->header_location.count = buf_size >> SECTOR_SHIFT;`
336			`lc->io_req.mem.type = DM_IO_VMA;`
337			`lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,`
338			`PAGE_SIZE));`
339			`if (IS_ERR(lc->io_req.client)) {`
340			`r = PTR_ERR(lc->io_req.client);`
341			`DMWARN("couldn't allocate disk io client");`
342			`kfree(lc);`
343			`return -ENOMEM;`
344			`}`
345
346			`lc->disk_header = vmalloc(buf_size);`
347			`if (!lc->disk_header) {`
348			`DMWARN("couldn't allocate disk log buffer");`
349			`kfree(lc);`
350			`return -ENOMEM;`
351			`}`
352
353			`lc->clean_bits = (void *)lc->disk_header +`
354			`(LOG_OFFSET << SECTOR_SHIFT);`
355			`}`
356
357			`memset(lc->clean_bits, -1, bitset_size);`
358
359			`lc->sync_bits = vmalloc(bitset_size);`
360			`if (!lc->sync_bits) {`
361			`DMWARN("couldn't allocate sync bitset");`
362			`if (!dev)`
363			`vfree(lc->clean_bits);`
364			`vfree(lc->disk_header);`
365			`kfree(lc);`
366			`return -ENOMEM;`
367			`}`
368			`memset(lc->sync_bits, (sync == NOSYNC) ? -1 : 0, bitset_size);`
369			`lc->sync_count = (sync == NOSYNC) ? region_count : 0;`
370
371			`lc->recovering_bits = vmalloc(bitset_size);`
372			`if (!lc->recovering_bits) {`
373			`DMWARN("couldn't allocate sync bitset");`
374			`vfree(lc->sync_bits);`
375			`if (!dev)`
376			`vfree(lc->clean_bits);`
377			`vfree(lc->disk_header);`
378			`kfree(lc);`
379			`return -ENOMEM;`
380			`}`
381			`memset(lc->recovering_bits, 0, bitset_size);`
382			`lc->sync_search = 0;`
383			`log->context = lc;`
384
385			`return 0;`
386			`}`
387
388			`static int core_ctr(struct dirty_log log, struct dm_target ti,`
389			`unsigned int argc, char **argv)`
390			`{`
391			`return create_log_context(log, ti, argc, argv, NULL);`
392			`}`
393
394			`static void destroy_log_context(struct log_c *lc)`
395			`{`
396			`vfree(lc->sync_bits);`
397			`vfree(lc->recovering_bits);`
398			`kfree(lc);`
399			`}`
400
401			`static void core_dtr(struct dirty_log *log)`
402			`{`
403			`struct log_c lc = (struct log_c ) log->context;`
404
405			`vfree(lc->clean_bits);`
406			`destroy_log_context(lc);`
407			`}`
408
409			`/*----------------------------------------------------------------`
410			`* disk log constructor/destructor`
411			`*`
412			`* argv contains log_device region_size followed optionally by [no]sync`
413			`--------------------------------------------------------------/`
414			`static int disk_ctr(struct dirty_log log, struct dm_target ti,`
415			`unsigned int argc, char **argv)`
416			`{`
417			`int r;`
418			`struct dm_dev *dev;`
419
420			`if (argc < 2 \|\| argc > 3) {`
421			`DMWARN("wrong number of arguments to disk mirror log");`
422			`return -EINVAL;`
423			`}`
424
425			`r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,`
426			`FMODE_READ \| FMODE_WRITE, &dev);`
427			`if (r)`
428			`return r;`
429
430			`r = create_log_context(log, ti, argc - 1, argv + 1, dev);`
431			`if (r) {`
432			`dm_put_device(ti, dev);`
433			`return r;`
434			`}`
435
436			`return 0;`
437			`}`
438
439			`static void disk_dtr(struct dirty_log *log)`
440			`{`
441			`struct log_c lc = (struct log_c ) log->context;`
442
443			`dm_put_device(lc->ti, lc->log_dev);`
444			`vfree(lc->disk_header);`
445			`dm_io_client_destroy(lc->io_req.client);`
446			`destroy_log_context(lc);`
447			`}`
448
449			`static int count_bits32(uint32_t *addr, unsigned size)`
450			`{`
451			`int count = 0, i;`
452
453			`for (i = 0; i < size; i++) {`
454			`count += hweight32(*(addr+i));`
455			`}`
456			`return count;`
457			`}`
458
459			`static void fail_log_device(struct log_c *lc)`
460			`{`
461			`if (lc->log_dev_failed)`
462			`return;`
463
464			`lc->log_dev_failed = 1;`
465			`dm_table_event(lc->ti->table);`
466			`}`
467
468			`static int disk_resume(struct dirty_log *log)`
469			`{`
470			`int r;`
471			`unsigned i;`
472			`struct log_c lc = (struct log_c ) log->context;`
473			`size_t size = lc->bitset_uint32_count * sizeof(uint32_t);`
474
475			`/* read the disk header */`
476			`r = read_header(lc);`
477			`if (r) {`
478			`DMWARN("%s: Failed to read header on mirror log device",`
479			`lc->log_dev->name);`
480			`fail_log_device(lc);`
481			`/*`
482			`* If the log device cannot be read, we must assume`
483			`* all regions are out-of-sync. If we simply return`
484			`* here, the state will be uninitialized and could`
485			`* lead us to return 'in-sync' status for regions`
486			`* that are actually 'out-of-sync'.`
487			`*/`
488			`lc->header.nr_regions = 0;`
489			`}`
490
491			`/* set or clear any new bits -- device has grown */`
492			`if (lc->sync == NOSYNC)`
493			`for (i = lc->header.nr_regions; i < lc->region_count; i++)`
494			`/* FIXME: amazingly inefficient */`
495			`log_set_bit(lc, lc->clean_bits, i);`
496			`else`
497			`for (i = lc->header.nr_regions; i < lc->region_count; i++)`
498			`/* FIXME: amazingly inefficient */`
499			`log_clear_bit(lc, lc->clean_bits, i);`
500
501			`/* clear any old bits -- device has shrunk */`
502			`for (i = lc->region_count; i % (sizeof(*lc->clean_bits) << BYTE_SHIFT); i++)`
503			`log_clear_bit(lc, lc->clean_bits, i);`
504
505			`/* copy clean across to sync */`
506			`memcpy(lc->sync_bits, lc->clean_bits, size);`
507			`lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);`
508			`lc->sync_search = 0;`
509
510			`/* set the correct number of regions in the header */`
511			`lc->header.nr_regions = lc->region_count;`
512
513			`/* write the new header */`
514			`r = write_header(lc);`
515			`if (r) {`
516			`DMWARN("%s: Failed to write header on mirror log device",`
517			`lc->log_dev->name);`
518			`fail_log_device(lc);`
519			`}`
520
521			`return r;`
522			`}`
523
524			`static uint32_t core_get_region_size(struct dirty_log *log)`
525			`{`
526			`struct log_c lc = (struct log_c ) log->context;`
527			`return lc->region_size;`
528			`}`
529
530			`static int core_resume(struct dirty_log *log)`
531			`{`
532			`struct log_c lc = (struct log_c ) log->context;`
533			`lc->sync_search = 0;`
534			`return 0;`
535			`}`
536
537			`static int core_is_clean(struct dirty_log *log, region_t region)`
538			`{`
539			`struct log_c lc = (struct log_c ) log->context;`
540			`return log_test_bit(lc->clean_bits, region);`
541			`}`
542
543			`static int core_in_sync(struct dirty_log *log, region_t region, int block)`
544			`{`
545			`struct log_c lc = (struct log_c ) log->context;`
546			`return log_test_bit(lc->sync_bits, region);`
547			`}`
548
549			`static int core_flush(struct dirty_log *log)`
550			`{`
551			`/* no op */`
552			`return 0;`
553			`}`
554
555			`static int disk_flush(struct dirty_log *log)`
556			`{`
557			`int r;`
558			`struct log_c lc = (struct log_c ) log->context;`
559
560			`/* only write if the log has changed */`
561			`if (!lc->touched)`
562			`return 0;`
563
564			`r = write_header(lc);`
565			`if (r)`
566			`fail_log_device(lc);`
567			`else`
568			`lc->touched = 0;`
569
570			`return r;`
571			`}`
572
573			`static void core_mark_region(struct dirty_log *log, region_t region)`
574			`{`
575			`struct log_c lc = (struct log_c ) log->context;`
576			`log_clear_bit(lc, lc->clean_bits, region);`
577			`}`
578
579			`static void core_clear_region(struct dirty_log *log, region_t region)`
580			`{`
581			`struct log_c lc = (struct log_c ) log->context;`
582			`log_set_bit(lc, lc->clean_bits, region);`
583			`}`
584
585			`static int core_get_resync_work(struct dirty_log log, region_t region)`
586			`{`
587			`struct log_c lc = (struct log_c ) log->context;`
588
589			`if (lc->sync_search >= lc->region_count)`
590			`return 0;`
591
592			`do {`
593			`*region = ext2_find_next_zero_bit(`
594			`(unsigned long *) lc->sync_bits,`
595			`lc->region_count,`
596			`lc->sync_search);`
597			`lc->sync_search = *region + 1;`
598
599			`if (*region >= lc->region_count)`
600			`return 0;`
601
602			`} while (log_test_bit(lc->recovering_bits, *region));`
603
604			`log_set_bit(lc, lc->recovering_bits, *region);`
605			`return 1;`
606			`}`
607
608			`static void core_set_region_sync(struct dirty_log *log, region_t region,`
609			`int in_sync)`
610			`{`
611			`struct log_c lc = (struct log_c ) log->context;`
612
613			`log_clear_bit(lc, lc->recovering_bits, region);`
614			`if (in_sync) {`
615			`log_set_bit(lc, lc->sync_bits, region);`
616			`lc->sync_count++;`
617			`} else if (log_test_bit(lc->sync_bits, region)) {`
618			`lc->sync_count--;`
619			`log_clear_bit(lc, lc->sync_bits, region);`
620			`}`
621			`}`
622
623			`static region_t core_get_sync_count(struct dirty_log *log)`
624			`{`
625			`struct log_c lc = (struct log_c ) log->context;`
626
627			`return lc->sync_count;`
628			`}`
629
630			`#define DMEMIT_SYNC \`
631			`if (lc->sync != DEFAULTSYNC) \`
632			`DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")`
633
634			`static int core_status(struct dirty_log *log, status_type_t status,`
635			`char *result, unsigned int maxlen)`
636			`{`
637			`int sz = 0;`
638			`struct log_c *lc = log->context;`
639
640			`switch(status) {`
641			`case STATUSTYPE_INFO:`
642			`DMEMIT("1 %s", log->type->name);`
643			`break;`
644
645			`case STATUSTYPE_TABLE:`
646			`DMEMIT("%s %u %u ", log->type->name,`
647			`lc->sync == DEFAULTSYNC ? 1 : 2, lc->region_size);`
648			`DMEMIT_SYNC;`
649			`}`
650
651			`return sz;`
652			`}`
653
654			`static int disk_status(struct dirty_log *log, status_type_t status,`
655			`char *result, unsigned int maxlen)`
656			`{`
657			`int sz = 0;`
658			`struct log_c *lc = log->context;`
659
660			`switch(status) {`
661			`case STATUSTYPE_INFO:`
662			`DMEMIT("3 %s %s %c", log->type->name, lc->log_dev->name,`
663			`lc->log_dev_failed ? 'D' : 'A');`
664			`break;`
665
666			`case STATUSTYPE_TABLE:`
667			`DMEMIT("%s %u %s %u ", log->type->name,`
668			`lc->sync == DEFAULTSYNC ? 2 : 3, lc->log_dev->name,`
669			`lc->region_size);`
670			`DMEMIT_SYNC;`
671			`}`
672
673			`return sz;`
674			`}`
675
676			`static struct dirty_log_type _core_type = {`
677			`.name = "core",`
678			`.module = THIS_MODULE,`
679			`.ctr = core_ctr,`
680			`.dtr = core_dtr,`
681			`.resume = core_resume,`
682			`.get_region_size = core_get_region_size,`
683			`.is_clean = core_is_clean,`
684			`.in_sync = core_in_sync,`
685			`.flush = core_flush,`
686			`.mark_region = core_mark_region,`
687			`.clear_region = core_clear_region,`
688			`.get_resync_work = core_get_resync_work,`
689			`.set_region_sync = core_set_region_sync,`
690			`.get_sync_count = core_get_sync_count,`
691			`.status = core_status,`
692			`};`
693
694			`static struct dirty_log_type _disk_type = {`
695			`.name = "disk",`
696			`.module = THIS_MODULE,`
697			`.ctr = disk_ctr,`
698			`.dtr = disk_dtr,`
699			`.postsuspend = disk_flush,`
700			`.resume = disk_resume,`
701			`.get_region_size = core_get_region_size,`
702			`.is_clean = core_is_clean,`
703			`.in_sync = core_in_sync,`
704			`.flush = disk_flush,`
705			`.mark_region = core_mark_region,`
706			`.clear_region = core_clear_region,`
707			`.get_resync_work = core_get_resync_work,`
708			`.set_region_sync = core_set_region_sync,`
709			`.get_sync_count = core_get_sync_count,`
710			`.status = disk_status,`
711			`};`
712
713			`int __init dm_dirty_log_init(void)`
714			`{`
715			`int r;`
716
717			`r = dm_register_dirty_log_type(&_core_type);`
718			`if (r)`
719			`DMWARN("couldn't register core log");`
720
721			`r = dm_register_dirty_log_type(&_disk_type);`
722			`if (r) {`
723			`DMWARN("couldn't register disk type");`
724			`dm_unregister_dirty_log_type(&_core_type);`
725			`}`
726
727			`return r;`
728			`}`
729
730			`void dm_dirty_log_exit(void)`
731			`{`
732			`dm_unregister_dirty_log_type(&_disk_type);`
733			`dm_unregister_dirty_log_type(&_core_type);`
734			`}`
735
736			`EXPORT_SYMBOL(dm_register_dirty_log_type);`
737			`EXPORT_SYMBOL(dm_unregister_dirty_log_type);`
738			`EXPORT_SYMBOL(dm_create_dirty_log);`
739			`EXPORT_SYMBOL(dm_destroy_dirty_log);`