Persistent log for mirroring. Compiles but not run yet.
--- diff/drivers/md/dm-log.c 2003-11-26 10:18:32.000000000 +0000
+++ source/drivers/md/dm-log.c 2003-12-10 13:34:26.000000000 +0000
@@ -69,7 +69,7 @@
spin_unlock(&_lock);
}
-struct dirty_log *dm_create_dirty_log(const char *type_name, sector_t dev_size,
+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;
@@ -86,7 +86,7 @@
}
log->type = type;
- if (type->ctr(log, dev_size, argc, argv)) {
+ if (type->ctr(log, ti, argc, argv)) {
kfree(log);
put_type(type);
return NULL;
@@ -102,37 +102,193 @@
kfree(log);
}
-
/*-----------------------------------------------------------------
- * In core log, ie. trivial, non-persistent
- *
- * For now we'll keep this simple and just have 2 bitsets, one
- * for clean/dirty, the other for sync/nosync. The sync bitset
- * will be freed when everything is in sync.
- *
- * FIXME: problems with a 64bit sector_t
+ * Persistent and core logs share a lot of their implementation.
+ * FIXME: need a reload method to be called from a resume
*---------------------------------------------------------------*/
-struct core_log {
+/*
+ * Magic for persistent mirrors: "MiRr"
+ */
+#define MIRROR_MAGIC 0x4D695272
+
+/*
+ * The on-disk version of the metadata.
+ */
+#define MIRROR_DISK_VERSION 1
+#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;
sector_t region_size;
unsigned int region_count;
- unsigned long *clean_bits;
- unsigned long *sync_bits;
- unsigned long *recovering_bits; /* FIXME: this seems excessive */
+
+ unsigned bitset_uint32_count;
+ uint32_t *clean_bits;
+ uint32_t *sync_bits;
+ uint32_t *recovering_bits; /* FIXME: this seems excessive */
int sync_search;
+
+ /*
+ * Disk log fields
+ */
+ struct dm_dev *log_dev;
+ struct log_header header;
+
+ struct io_region header_location;
+ struct page *header_pages;
+ struct log_header *disk_header;
+
+ struct io_region bits_location;
+ struct page *bits_pages;
+ uint32_t *disk_bits;
};
+/*
+ * 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(bit, (unsigned long *) bs) ? 1 : 0;
+}
+
+static inline void log_set_bit(struct log_c *l,
+ uint32_t *bs, unsigned bit)
+{
+ set_bit(bit, (unsigned long *) bs);
+ l->touched = 1;
+}
+
+static inline void log_clear_bit(struct log_c *l,
+ uint32_t *bs, unsigned bit)
+{
+ 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(1, &log->header_location, READ,
+ log->header_pages, 0, &ebits);
+ if (r)
+ return r;
+
+ header_from_disk(&log->header, log->disk_header);
+
+ if (log->header.magic != MIRROR_MAGIC) {
+ log->header.magic = MIRROR_MAGIC;
+ log->header.version = MIRROR_DISK_VERSION;
+ log->header.nr_regions = 0;
+ }
+
+ 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(1, &log->header_location, WRITE,
+ log->header_pages, 0, &ebits);
+}
+
+/*----------------------------------------------------------------
+ * Bits IO
+ *--------------------------------------------------------------*/
+static inline void bits_to_core(uint32_t *core, uint32_t *disk, unsigned count)
+{
+ unsigned i;
+
+ for (i = 0; i < count; i++)
+ core[i] = le32_to_cpu(disk[i]);
+}
+
+static inline void bits_to_disk(uint32_t *core, uint32_t *disk, unsigned count)
+{
+ unsigned i;
+
+ /* copy across the clean/dirty bitset */
+ for (i = 0; i < i; i++)
+ disk[i] = cpu_to_le32(core[i]);
+}
+
+static int read_bits(struct log_c *log)
+{
+ int r;
+ unsigned long ebits;
+
+ r = dm_io_sync(1, &log->bits_location, READ,
+ log->bits_pages, 0, &ebits);
+ if (r)
+ return r;
+
+ bits_to_core(log->clean_bits, log->disk_bits,
+ log->bitset_uint32_count);
+ return 0;
+}
+
+static int write_bits(struct log_c *log)
+{
+ unsigned long ebits;
+ bits_to_disk(log->clean_bits, log->disk_bits,
+ log->bitset_uint32_count);
+ return dm_io_sync(1, &log->bits_location, WRITE,
+ log->bits_pages, 0, &ebits);
+}
+
+/*----------------------------------------------------------------
+ * constructor/destructor
+ *--------------------------------------------------------------*/
#define BYTE_SHIFT 3
-static int core_ctr(struct dirty_log *log, sector_t dev_size,
+static int core_ctr(struct dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
- struct core_log *clog;
+ struct log_c *lc;
sector_t region_size;
unsigned int region_count;
size_t bitset_size;
if (argc != 1) {
- DMWARN("wrong number of arguments to core_log");
+ DMWARN("wrong number of arguments to log_c");
return -EINVAL;
}
@@ -141,81 +297,182 @@
return -EINVAL;
}
- region_count = dm_div_up(dev_size, region_size);
+ region_count = dm_div_up(ti->len, region_size);
- clog = kmalloc(sizeof(*clog), GFP_KERNEL);
- if (!clog) {
+ lc = kmalloc(sizeof(*lc), GFP_KERNEL);
+ if (!lc) {
DMWARN("couldn't allocate core log");
return -ENOMEM;
}
- clog->region_size = region_size;
- clog->region_count = region_count;
+ lc->ti = ti;
+ lc->touched = 0;
+ lc->region_size = region_size;
+ lc->region_count = region_count;
/*
* Work out how many words we need to hold the bitset.
*/
bitset_size = dm_round_up(region_count,
- sizeof(*clog->clean_bits) << BYTE_SHIFT);
+ sizeof(*lc->clean_bits) << BYTE_SHIFT);
bitset_size >>= BYTE_SHIFT;
- clog->clean_bits = vmalloc(bitset_size);
- if (!clog->clean_bits) {
+ lc->bitset_uint32_count = bitset_size / 4;
+ lc->clean_bits = vmalloc(bitset_size);
+ if (!lc->clean_bits) {
DMWARN("couldn't allocate clean bitset");
- kfree(clog);
+ kfree(lc);
return -ENOMEM;
}
- memset(clog->clean_bits, -1, bitset_size);
+ memset(lc->clean_bits, -1, bitset_size);
- clog->sync_bits = vmalloc(bitset_size);
- if (!clog->sync_bits) {
+ lc->sync_bits = vmalloc(bitset_size);
+ if (!lc->sync_bits) {
DMWARN("couldn't allocate sync bitset");
- vfree(clog->clean_bits);
- kfree(clog);
+ vfree(lc->clean_bits);
+ kfree(lc);
return -ENOMEM;
}
- memset(clog->sync_bits, 0, bitset_size);
+ memset(lc->sync_bits, 0, bitset_size);
- clog->recovering_bits = vmalloc(bitset_size);
- if (!clog->recovering_bits) {
+ lc->recovering_bits = vmalloc(bitset_size);
+ if (!lc->recovering_bits) {
DMWARN("couldn't allocate sync bitset");
- vfree(clog->sync_bits);
- vfree(clog->clean_bits);
- kfree(clog);
+ vfree(lc->sync_bits);
+ vfree(lc->clean_bits);
+ kfree(lc);
return -ENOMEM;
}
- memset(clog->recovering_bits, 0, bitset_size);
- clog->sync_search = 0;
- log->context = clog;
+ memset(lc->recovering_bits, 0, bitset_size);
+ lc->sync_search = 0;
+ log->context = lc;
return 0;
}
static void core_dtr(struct dirty_log *log)
{
- struct core_log *clog = (struct core_log *) log->context;
- vfree(clog->clean_bits);
- vfree(clog->sync_bits);
- vfree(clog->recovering_bits);
- kfree(clog);
+ struct log_c *lc = (struct log_c *) log->context;
+ vfree(lc->clean_bits);
+ vfree(lc->sync_bits);
+ vfree(lc->recovering_bits);
+ kfree(lc);
+}
+
+static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
+ unsigned int argc, char **argv)
+{
+ int r;
+ size_t size;
+ struct log_c *lc;
+ struct dm_dev *dev;
+
+ r = dm_get_device(ti, argv[0], 0, 0 /* FIXME */,
+ FMODE_READ | FMODE_WRITE, &dev);
+ if (r)
+ return r;
+
+ r = core_ctr(log, ti, argc - 1, argv + 1);
+ if (r) {
+ dm_put_device(ti, dev);
+ return r;
+ }
+
+ lc = (struct log_c *) log->context;
+ lc->log_dev = dev;
+
+ /* setup the disk header fields */
+ lc->header_location.bdev = lc->log_dev->bdev;
+ lc->header_location.sector = 0;
+ lc->header_location.count = 1;
+ lc->disk_header = vmalloc(sizeof(struct log_header));
+ if (!lc->disk_header)
+ goto bad;
+
+ lc->header_pages = vmalloc_to_page(lc->disk_header);
+
+ /* setup the disk bitset fields */
+ lc->bits_location.bdev = lc->log_dev->bdev;
+ lc->bits_location.sector = LOG_OFFSET;
+
+ size = dm_round_up(lc->bitset_uint32_count * sizeof(uint32_t),
+ 1 << SECTOR_SHIFT);
+ lc->bits_location.count = size >> SECTOR_SHIFT;
+ lc->disk_bits = vmalloc(size);
+ if (!lc->disk_bits) {
+ vfree(lc->disk_header);
+ goto bad;
+ }
+ lc->bits_pages = vmalloc_to_page(lc->disk_bits);
+ return 0;
+
+ bad:
+ dm_put_device(ti, lc->log_dev);
+ core_dtr(log);
+ return -ENOMEM;
+}
+
+static void disk_dtr(struct dirty_log *log)
+{
+ struct log_c *lc = (struct log_c *) log->context;
+ core_dtr(log);
+ dm_put_device(lc->ti, lc->log_dev);
+ vfree(lc->disk_header);
+ vfree(lc->disk_bits);
+}
+
+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;
+
+ /* read the bits */
+ r = read_bits(lc);
+ if (r)
+ return r;
+
+ /* zero any new bits if the mirror has grown */
+ for (i = lc->header.nr_regions; i < lc->region_count; i++)
+ /* FIXME: amazingly inefficient */
+ log_clear_bit(lc, lc->clean_bits, i);
+
+ /* copy clean across to sync */
+ memcpy(lc->sync_bits, lc->clean_bits, size);
+
+ /* write the bits */
+ r = write_bits(lc);
+ if (r)
+ return r;
+
+ /* 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 sector_t core_get_region_size(struct dirty_log *log)
{
- struct core_log *clog = (struct core_log *) log->context;
- return clog->region_size;
+ 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 core_log *clog = (struct core_log *) log->context;
- return test_bit(region, clog->clean_bits);
+ 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 core_log *clog = (struct core_log *) log->context;
-
- return test_bit(region, clog->sync_bits) ? 1 : 0;
+ 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)
@@ -224,53 +481,68 @@
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_bits(lc);
+ if (!r)
+ lc->touched = 0;
+
+ return r;
+}
+
static void core_mark_region(struct dirty_log *log, region_t region)
{
- struct core_log *clog = (struct core_log *) log->context;
- clear_bit(region, clog->clean_bits);
+ 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 core_log *clog = (struct core_log *) log->context;
- set_bit(region, clog->clean_bits);
+ 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 core_log *clog = (struct core_log *) log->context;
+ struct log_c *lc = (struct log_c *) log->context;
- if (clog->sync_search >= clog->region_count)
+ if (lc->sync_search >= lc->region_count)
return 0;
do {
- *region = find_next_zero_bit(clog->sync_bits,
- clog->region_count,
- clog->sync_search);
- clog->sync_search = *region + 1;
+ *region = find_next_zero_bit((unsigned long *) lc->sync_bits,
+ lc->region_count,
+ lc->sync_search);
+ lc->sync_search = *region + 1;
- if (*region == clog->region_count)
+ if (*region == lc->region_count)
return 0;
- } while (test_bit(*region, clog->recovering_bits));
+ } while (log_test_bit(lc->recovering_bits, *region));
- set_bit(*region, clog->recovering_bits);
+ 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 core_log *clog = (struct core_log *) log->context;
+ struct log_c *lc = (struct log_c *) log->context;
- clear_bit(region, clog->recovering_bits);
+ log_clear_bit(lc, lc->recovering_bits, region);
if (success)
- set_bit(region, clog->sync_bits);
+ log_set_bit(lc, lc->sync_bits, region);
}
static struct dirty_log_type _core_type = {
.name = "core",
-
.ctr = core_ctr,
.dtr = core_dtr,
.get_region_size = core_get_region_size,
@@ -283,6 +555,21 @@
.complete_resync_work = core_complete_resync_work
};
+static struct dirty_log_type _disk_type = {
+ .name = "disk",
+ .ctr = disk_ctr,
+ .dtr = disk_dtr,
+ .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
+};
+
__init int dm_dirty_log_init(void)
{
int r;
@@ -291,11 +578,18 @@
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);
}
--- diff/drivers/md/dm-log.h 2003-11-26 10:18:32.000000000 +0000
+++ source/drivers/md/dm-log.h 2003-12-10 13:02:37.000000000 +0000
@@ -24,11 +24,18 @@
struct module *module;
unsigned int use_count;
- int (*ctr)(struct dirty_log *log, sector_t dev_size,
+ int (*ctr)(struct dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv);
void (*dtr)(struct dirty_log *log);
/*
+ * There are times when we don't want the log to touch
+ * the disk.
+ */
+ int (*suspend)(struct dirty_log *log);
+ int (*resume)(struct dirty_log *log);
+
+ /*
* Retrieves the smallest size of region that the log can
* deal with.
*/
@@ -99,7 +106,7 @@
* Make sure you use these two functions, rather than calling
* type->constructor/destructor() directly.
*/
-struct dirty_log *dm_create_dirty_log(const char *type_name, sector_t dev_size,
+struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
unsigned int argc, char **argv);
void dm_destroy_dirty_log(struct dirty_log *log);
--- diff/drivers/md/dm-raid1.c 2003-12-04 11:18:37.000000000 +0000
+++ source/drivers/md/dm-raid1.c 2003-12-10 13:37:42.000000000 +0000
@@ -637,6 +637,8 @@
struct region *reg = (struct region *) context;
struct mirror_set *ms = reg->rh->ms;
+ /* FIXME: we need to flush the log */
+
/* FIXME: better error handling */
rh_recovery_end(reg, read_err || write_err);
if (++ms->sync_count == ms->nr_regions)
@@ -1025,7 +1027,7 @@
return NULL;
}
- dl = dm_create_dirty_log(argv[0], ti->len, param_count, argv + 2);
+ dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2);
if (!dl) {
ti->error = "dm-mirror: Error creating mirror dirty log";
return NULL;
@@ -1198,12 +1200,20 @@
static void mirror_suspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
+ struct dirty_log *log = ms->rh.log;
rh_stop_recovery(&ms->rh);
+ if (log->type->suspend && log->type->suspend(log))
+ /* FIXME: need better error handling */
+ DMWARN("log suspend failed");
}
static void mirror_resume(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
+ struct dirty_log *log = ms->rh.log;
+ if (log->type->resume && log->type->resume(log))
+ /* FIXME: need better error handling */
+ DMWARN("log resume failed");
rh_start_recovery(&ms->rh);
}