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;
}
/* Version 2 is like version 1 but always little endian on disk. */
#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 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 = WRITE_FLUSH;
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 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 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 inline int write_header(struct log_c *log)
{
header_to_disk(&log->header, log->disk_header);
return rw_header(log, WRITE);
}
