#include "dm.h"
#include "dm-bio-list.h"
+#include "dm-bio-record.h"
#include "dm-io.h"
#include "dm-log.h"
#include "kcopyd.h"
struct mirror {
struct mirror_set *ms;
atomic_t error_count;
- uint32_t error_type;
+ unsigned long error_type;
struct dm_dev *dev;
sector_t offset;
};
struct bio_list failures;
struct dm_io_client *io_client;
+ mempool_t *read_record_pool;
/* recovery */
region_t nr_regions;
int in_sync;
int log_failure;
+ atomic_t suspend;
atomic_t default_mirror; /* Default mirror */
struct region_hash *rh = reg->rh;
rh->log->type->set_region_sync(rh->log, reg->key, success);
+
+ /*
+ * Dispatch the bios before we call 'wake_up_all'.
+ * This is important because if we are suspending,
+ * we want to know that recovery is complete and
+ * the work queue is flushed. If we wake_up_all
+ * before we dispatch_bios (queue bios and call wake()),
+ * then we risk suspending before the work queue
+ * has been properly flushed.
+ */
dispatch_bios(rh->ms, ®->delayed_bios);
if (atomic_dec_and_test(&rh->recovery_in_flight))
wake_up_all(&_kmirrord_recovery_stopped);
wake(rh->ms);
}
+#define MIN_READ_RECORDS 20
+struct dm_raid1_read_record {
+ struct mirror *m;
+ struct dm_bio_details details;
+};
+
/*
* Every mirror should look like this one.
*/
#define DEFAULT_MIRROR 0
/*
- * This is yucky. We squirrel the mirror_set struct away inside
- * bi_next for write buffers. This is safe since the bh
+ * This is yucky. We squirrel the mirror struct away inside
+ * bi_next for read/write buffers. This is safe since the bh
* doesn't get submitted to the lower levels of block layer.
*/
-static struct mirror_set *bio_get_ms(struct bio *bio)
+static struct mirror *bio_get_m(struct bio *bio)
{
- return (struct mirror_set *) bio->bi_next;
+ return (struct mirror *) bio->bi_next;
}
-static void bio_set_ms(struct bio *bio, struct mirror_set *ms)
+static void bio_set_m(struct bio *bio, struct mirror *m)
{
- bio->bi_next = (struct bio *) ms;
+ bio->bi_next = (struct bio *) m;
}
static struct mirror *get_default_mirror(struct mirror_set *ms)
* are in the no-sync state. We have to recover these by
* recopying from the default mirror to all the others.
*---------------------------------------------------------------*/
-static void recovery_complete(int read_err, unsigned int write_err,
+static void recovery_complete(int read_err, unsigned long write_err,
void *context)
{
struct region *reg = (struct region *)context;
}
if (write_err) {
- DMERR_LIMIT("Write error during recovery (error = 0x%x)",
+ DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
write_err);
/*
* Bits correspond to devices (excluding default mirror).
*---------------------------------------------------------------*/
static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
{
- /* FIXME: add read balancing */
- return get_default_mirror(ms);
+ struct mirror *m = get_default_mirror(ms);
+
+ do {
+ if (likely(!atomic_read(&m->error_count)))
+ return m;
+
+ if (m-- == ms->mirror)
+ m += ms->nr_mirrors;
+ } while (m != get_default_mirror(ms));
+
+ return NULL;
+}
+
+static int default_ok(struct mirror *m)
+{
+ struct mirror *default_mirror = get_default_mirror(m->ms);
+
+ return !atomic_read(&default_mirror->error_count);
+}
+
+static int mirror_available(struct mirror_set *ms, struct bio *bio)
+{
+ region_t region = bio_to_region(&ms->rh, bio);
+
+ if (ms->rh.log->type->in_sync(ms->rh.log, region, 0))
+ return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
+
+ return 0;
}
/*
* remap a buffer to a particular mirror.
*/
-static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio)
+static sector_t map_sector(struct mirror *m, struct bio *bio)
+{
+ return m->offset + (bio->bi_sector - m->ms->ti->begin);
+}
+
+static void map_bio(struct mirror *m, struct bio *bio)
{
bio->bi_bdev = m->dev->bdev;
- bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin);
+ bio->bi_sector = map_sector(m, bio);
+}
+
+static void map_region(struct io_region *io, struct mirror *m,
+ struct bio *bio)
+{
+ io->bdev = m->dev->bdev;
+ io->sector = map_sector(m, bio);
+ io->count = bio->bi_size >> 9;
+}
+
+/*-----------------------------------------------------------------
+ * Reads
+ *---------------------------------------------------------------*/
+static void read_callback(unsigned long error, void *context)
+{
+ struct bio *bio = context;
+ struct mirror *m;
+
+ m = bio_get_m(bio);
+ bio_set_m(bio, NULL);
+
+ if (likely(!error)) {
+ bio_endio(bio, 0);
+ return;
+ }
+
+ fail_mirror(m, DM_RAID1_READ_ERROR);
+
+ if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
+ DMWARN_LIMIT("Read failure on mirror device %s. "
+ "Trying alternative device.",
+ m->dev->name);
+ queue_bio(m->ms, bio, bio_rw(bio));
+ return;
+ }
+
+ DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
+ m->dev->name);
+ bio_endio(bio, -EIO);
+}
+
+/* Asynchronous read. */
+static void read_async_bio(struct mirror *m, struct bio *bio)
+{
+ struct io_region io;
+ struct dm_io_request io_req = {
+ .bi_rw = READ,
+ .mem.type = DM_IO_BVEC,
+ .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
+ .notify.fn = read_callback,
+ .notify.context = bio,
+ .client = m->ms->io_client,
+ };
+
+ map_region(&io, m, bio);
+ bio_set_m(bio, m);
+ (void) dm_io(&io_req, 1, &io, NULL);
}
static void do_reads(struct mirror_set *ms, struct bio_list *reads)
while ((bio = bio_list_pop(reads))) {
region = bio_to_region(&ms->rh, bio);
+ m = get_default_mirror(ms);
/*
* We can only read balance if the region is in sync.
*/
- if (rh_in_sync(&ms->rh, region, 1))
+ if (likely(rh_in_sync(&ms->rh, region, 1)))
m = choose_mirror(ms, bio->bi_sector);
- else
- m = get_default_mirror(ms);
+ else if (m && atomic_read(&m->error_count))
+ m = NULL;
- map_bio(ms, m, bio);
- generic_make_request(bio);
+ if (likely(m))
+ read_async_bio(m, bio);
+ else
+ bio_endio(bio, -EIO);
}
}
int should_wake = 0;
unsigned long flags;
- ms = bio_get_ms(bio);
- bio_set_ms(bio, NULL);
+ ms = bio_get_m(bio)->ms;
+ bio_set_m(bio, NULL);
/*
* NOTE: We don't decrement the pending count here,
static void do_write(struct mirror_set *ms, struct bio *bio)
{
unsigned int i;
- struct io_region io[KCOPYD_MAX_REGIONS+1];
+ struct io_region io[ms->nr_mirrors], *dest = io;
struct mirror *m;
struct dm_io_request io_req = {
.bi_rw = WRITE,
.client = ms->io_client,
};
- for (i = 0; i < ms->nr_mirrors; i++) {
- m = ms->mirror + i;
+ for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
+ map_region(dest++, m, bio);
- io[i].bdev = m->dev->bdev;
- io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin);
- io[i].count = bio->bi_size >> 9;
- }
-
- bio_set_ms(bio, ms);
+ /*
+ * Use default mirror because we only need it to retrieve the reference
+ * to the mirror set in write_callback().
+ */
+ bio_set_m(bio, get_default_mirror(ms));
(void) dm_io(&io_req, ms->nr_mirrors, io, NULL);
}
/*
* Dispatch io.
*/
- if (unlikely(ms->log_failure))
+ if (unlikely(ms->log_failure)) {
+ spin_lock_irq(&ms->lock);
+ bio_list_merge(&ms->failures, &sync);
+ spin_unlock_irq(&ms->lock);
+ } else
while ((bio = bio_list_pop(&sync)))
- bio_endio(bio, -EIO);
- else while ((bio = bio_list_pop(&sync)))
- do_write(ms, bio);
+ do_write(ms, bio);
while ((bio = bio_list_pop(&recover)))
rh_delay(&ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
- map_bio(ms, get_default_mirror(ms), bio);
+ map_bio(get_default_mirror(ms), bio);
generic_make_request(bio);
}
}
if (!failures->head)
return;
- while ((bio = bio_list_pop(failures)))
- __bio_mark_nosync(ms, bio, bio->bi_size, 0);
+ if (!ms->log_failure) {
+ while ((bio = bio_list_pop(failures)))
+ __bio_mark_nosync(ms, bio, bio->bi_size, 0);
+ return;
+ }
+
+ /*
+ * If the log has failed, unattempted writes are being
+ * put on the failures list. We can't issue those writes
+ * until a log has been marked, so we must store them.
+ *
+ * If a 'noflush' suspend is in progress, we can requeue
+ * the I/O's to the core. This give userspace a chance
+ * to reconfigure the mirror, at which point the core
+ * will reissue the writes. If the 'noflush' flag is
+ * not set, we have no choice but to return errors.
+ *
+ * Some writes on the failures list may have been
+ * submitted before the log failure and represent a
+ * failure to write to one of the devices. It is ok
+ * for us to treat them the same and requeue them
+ * as well.
+ */
+ if (dm_noflush_suspending(ms->ti)) {
+ while ((bio = bio_list_pop(failures)))
+ bio_endio(bio, DM_ENDIO_REQUEUE);
+ return;
+ }
+
+ if (atomic_read(&ms->suspend)) {
+ while ((bio = bio_list_pop(failures)))
+ bio_endio(bio, -EIO);
+ return;
+ }
+
+ spin_lock_irq(&ms->lock);
+ bio_list_merge(&ms->failures, failures);
+ spin_unlock_irq(&ms->lock);
+
+ wake(ms);
}
static void trigger_event(struct work_struct *work)
ms->nr_mirrors = nr_mirrors;
ms->nr_regions = dm_sector_div_up(ti->len, region_size);
ms->in_sync = 0;
+ ms->log_failure = 0;
+ atomic_set(&ms->suspend, 0);
atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
+ len = sizeof(struct dm_raid1_read_record);
+ ms->read_record_pool = mempool_create_kmalloc_pool(MIN_READ_RECORDS,
+ len);
+ if (!ms->read_record_pool) {
+ ti->error = "Error creating mirror read_record_pool";
+ kfree(ms);
+ return NULL;
+ }
+
ms->io_client = dm_io_client_create(DM_IO_PAGES);
if (IS_ERR(ms->io_client)) {
ti->error = "Error creating dm_io client";
+ mempool_destroy(ms->read_record_pool);
kfree(ms);
return NULL;
}
if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
ti->error = "Error creating dirty region hash";
dm_io_client_destroy(ms->io_client);
+ mempool_destroy(ms->read_record_pool);
kfree(ms);
return NULL;
}
dm_io_client_destroy(ms->io_client);
rh_exit(&ms->rh);
+ mempool_destroy(ms->read_record_pool);
kfree(ms);
}
int r, rw = bio_rw(bio);
struct mirror *m;
struct mirror_set *ms = ti->private;
-
- map_context->ll = bio_to_region(&ms->rh, bio);
+ struct dm_raid1_read_record *read_record = NULL;
if (rw == WRITE) {
+ /* Save region for mirror_end_io() handler */
+ map_context->ll = bio_to_region(&ms->rh, bio);
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
if (r < 0 && r != -EWOULDBLOCK)
return r;
- if (r == -EWOULDBLOCK) /* FIXME: ugly */
- r = DM_MAPIO_SUBMITTED;
-
/*
- * We don't want to fast track a recovery just for a read
- * ahead. So we just let it silently fail.
- * FIXME: get rid of this.
+ * If region is not in-sync queue the bio.
*/
- if (!r && rw == READA)
- return -EIO;
+ if (!r || (r == -EWOULDBLOCK)) {
+ if (rw == READA)
+ return -EWOULDBLOCK;
- if (!r) {
- /* Pass this io over to the daemon */
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
+ /*
+ * The region is in-sync and we can perform reads directly.
+ * Store enough information so we can retry if it fails.
+ */
m = choose_mirror(ms, bio->bi_sector);
- if (!m)
+ if (unlikely(!m))
return -EIO;
- map_bio(ms, m, bio);
+ read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO);
+ if (likely(read_record)) {
+ dm_bio_record(&read_record->details, bio);
+ map_context->ptr = read_record;
+ read_record->m = m;
+ }
+
+ map_bio(m, bio);
+
return DM_MAPIO_REMAPPED;
}
{
int rw = bio_rw(bio);
struct mirror_set *ms = (struct mirror_set *) ti->private;
- region_t region = map_context->ll;
+ struct mirror *m = NULL;
+ struct dm_bio_details *bd = NULL;
+ struct dm_raid1_read_record *read_record = map_context->ptr;
/*
* We need to dec pending if this was a write.
*/
- if (rw == WRITE)
- rh_dec(&ms->rh, region);
+ if (rw == WRITE) {
+ rh_dec(&ms->rh, map_context->ll);
+ return error;
+ }
- return 0;
+ if (error == -EOPNOTSUPP)
+ goto out;
+
+ if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
+ goto out;
+
+ if (unlikely(error)) {
+ if (!read_record) {
+ /*
+ * There wasn't enough memory to record necessary
+ * information for a retry or there was no other
+ * mirror in-sync.
+ */
+ DMERR_LIMIT("Mirror read failed.");
+ return -EIO;
+ }
+
+ m = read_record->m;
+
+ DMERR("Mirror read failed from %s. Trying alternative device.",
+ m->dev->name);
+
+ fail_mirror(m, DM_RAID1_READ_ERROR);
+
+ /*
+ * A failed read is requeued for another attempt using an intact
+ * mirror.
+ */
+ if (default_ok(m) || mirror_available(ms, bio)) {
+ bd = &read_record->details;
+
+ dm_bio_restore(bd, bio);
+ mempool_free(read_record, ms->read_record_pool);
+ map_context->ptr = NULL;
+ queue_bio(ms, bio, rw);
+ return 1;
+ }
+ DMERR("All replicated volumes dead, failing I/O");
+ }
+
+out:
+ if (read_record) {
+ mempool_free(read_record, ms->read_record_pool);
+ map_context->ptr = NULL;
+ }
+
+ return error;
}
-static void mirror_postsuspend(struct dm_target *ti)
+static void mirror_presuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dirty_log *log = ms->rh.log;
+ atomic_set(&ms->suspend, 1);
+
+ /*
+ * We must finish up all the work that we've
+ * generated (i.e. recovery work).
+ */
rh_stop_recovery(&ms->rh);
- /* Wait for all I/O we generated to complete */
wait_event(_kmirrord_recovery_stopped,
!atomic_read(&ms->rh.recovery_in_flight));
+ if (log->type->presuspend && log->type->presuspend(log))
+ /* FIXME: need better error handling */
+ DMWARN("log presuspend failed");
+
+ /*
+ * Now that recovery is complete/stopped and the
+ * delayed bios are queued, we need to wait for
+ * the worker thread to complete. This way,
+ * we know that all of our I/O has been pushed.
+ */
+ flush_workqueue(ms->kmirrord_wq);
+}
+
+static void mirror_postsuspend(struct dm_target *ti)
+{
+ struct mirror_set *ms = ti->private;
+ struct dirty_log *log = ms->rh.log;
+
if (log->type->postsuspend && log->type->postsuspend(log))
/* FIXME: need better error handling */
- DMWARN("log suspend failed");
+ DMWARN("log postsuspend failed");
}
static void mirror_resume(struct dm_target *ti)
{
- struct mirror_set *ms = (struct mirror_set *) ti->private;
+ struct mirror_set *ms = ti->private;
struct dirty_log *log = ms->rh.log;
+
+ atomic_set(&ms->suspend, 0);
if (log->type->resume && log->type->resume(log))
/* FIXME: need better error handling */
DMWARN("log resume failed");
rh_start_recovery(&ms->rh);
}
+/*
+ * device_status_char
+ * @m: mirror device/leg we want the status of
+ *
+ * We return one character representing the most severe error
+ * we have encountered.
+ * A => Alive - No failures
+ * D => Dead - A write failure occurred leaving mirror out-of-sync
+ * S => Sync - A sychronization failure occurred, mirror out-of-sync
+ * R => Read - A read failure occurred, mirror data unaffected
+ *
+ * Returns: <char>
+ */
+static char device_status_char(struct mirror *m)
+{
+ if (!atomic_read(&(m->error_count)))
+ return 'A';
+
+ return (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
+ (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
+ (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
+}
+
+
static int mirror_status(struct dm_target *ti, status_type_t type,
char *result, unsigned int maxlen)
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
+ struct dirty_log *log = ms->rh.log;
+ char buffer[ms->nr_mirrors + 1];
switch (type) {
case STATUSTYPE_INFO:
DMEMIT("%d ", ms->nr_mirrors);
- for (m = 0; m < ms->nr_mirrors; m++)
+ for (m = 0; m < ms->nr_mirrors; m++) {
DMEMIT("%s ", ms->mirror[m].dev->name);
+ buffer[m] = device_status_char(&(ms->mirror[m]));
+ }
+ buffer[m] = '\0';
- DMEMIT("%llu/%llu 0 ",
- (unsigned long long)ms->rh.log->type->
- get_sync_count(ms->rh.log),
- (unsigned long long)ms->nr_regions);
+ DMEMIT("%llu/%llu 1 %s ",
+ (unsigned long long)log->type->get_sync_count(ms->rh.log),
+ (unsigned long long)ms->nr_regions, buffer);
- sz += ms->rh.log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
+ sz += log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
break;
case STATUSTYPE_TABLE:
- sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen);
+ sz = log->type->status(ms->rh.log, type, result, maxlen);
DMEMIT("%d", ms->nr_mirrors);
for (m = 0; m < ms->nr_mirrors; m++)
DMEMIT(" %s %llu", ms->mirror[m].dev->name,
- (unsigned long long)ms->mirror[m].offset);
+ (unsigned long long)ms->mirror[m].offset);
if (ms->features & DM_RAID1_HANDLE_ERRORS)
DMEMIT(" 1 handle_errors");
static struct target_type mirror_target = {
.name = "mirror",
- .version = {1, 0, 3},
+ .version = {1, 0, 20},
.module = THIS_MODULE,
.ctr = mirror_ctr,
.dtr = mirror_dtr,
.map = mirror_map,
.end_io = mirror_end_io,
+ .presuspend = mirror_presuspend,
.postsuspend = mirror_postsuspend,
.resume = mirror_resume,
.status = mirror_status,
projects / linux-2.6 / blobdiff