Refreshed to linux-2.6.25-rc5-mm1.
This patch generates a uevent on a device failure and does NOT process
further writes until it receives 'unblock' message. LVM or other tools
are expected to get the miror-set status upon receiving the above uevent
and record the failed device in their metadata, and then send the
'unblock' message to the dm-raid1 target.
Please comment. This would help LVM select the right master device at
mirror logical volume activation/load time.
Signed-off-by: Malahal Naineni <malahal@xxxxxxxxxx>
diff -r bfb50ef53671 drivers/md/dm-raid1.c
--- a/drivers/md/dm-raid1.c Mon Mar 31 10:13:13 2008 -0700
+++ b/drivers/md/dm-raid1.c Tue Apr 01 16:09:09 2008 -0700
@@ -10,6 +10,7 @@
#include "dm-io.h"
#include "dm-log.h"
#include "kcopyd.h"
+#include "dm-uevent.h"
#include <linux/ctype.h>
#include <linux/init.h>
@@ -26,8 +27,11 @@
#define DM_MSG_PREFIX "raid1"
#define DM_IO_PAGES 64
-#define DM_RAID1_HANDLE_ERRORS 0x01
+#define DM_RAID1_HANDLE_ERRORS 0x01
+#define DM_RAID1_BLOCK_ON_ERROR 0x02
#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
+#define block_on_error(p) ((p)->features & DM_RAID1_BLOCK_ON_ERROR)
+#define handle_all_errors(p) (errors_handled(p) || block_on_error(p))
static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
@@ -148,6 +152,7 @@ struct mirror_set {
region_t nr_regions;
int in_sync;
int log_failure;
+ int write_blocked;
atomic_t suspend;
atomic_t default_mirror; /* Default mirror */
@@ -443,7 +448,7 @@ static void rh_update_states(struct regi
}
list_for_each_entry_safe(reg, next, &failed_recovered, list) {
- complete_resync_work(reg, errors_handled(rh->ms) ? 0 : 1);
+ complete_resync_work(reg, handle_all_errors(rh->ms) ? 0 : 1);
mempool_free(reg, rh->region_pool);
}
@@ -706,8 +711,10 @@ static void fail_mirror(struct mirror *m
{
struct mirror_set *ms = m->ms;
struct mirror *new;
+ unsigned long flags;
+ int generate_uevent = 0;
- if (!errors_handled(ms))
+ if (!handle_all_errors(ms))
return;
/*
@@ -719,6 +726,25 @@ static void fail_mirror(struct mirror *m
if (test_and_set_bit(error_type, &m->error_type))
return;
+
+ /*
+ * Make sure that device failure is recorded in the metadata
+ * before allowing any new writes. Agent acting on the following
+ * uevent should query the status of the mirrorset, update
+ * metadata accordingly and then send the unblock message.
+ */
+ if (block_on_error(ms)) {
+ spin_lock_irqsave(&ms->lock, flags);
+ if (!ms->write_blocked) {
+ ms->write_blocked = 1;
+ generate_uevent = 1;
+ }
+ spin_unlock_irqrestore(&ms->lock, flags);
+ if (generate_uevent) {
+ dm_dev_uevent(DM_UEVENT_DEV_CHANGE, ms->ti);
+ schedule_work(&ms->trigger_event);
+ }
+ }
if (m != get_default_mirror(ms))
goto out;
@@ -835,6 +861,7 @@ static void do_recovery(struct mirror_se
int r;
struct region *reg;
struct dm_dirty_log *log = ms->rh.log;
+ struct mirror *m;
/*
* Start quiescing some regions.
@@ -855,6 +882,10 @@ static void do_recovery(struct mirror_se
*/
if (!ms->in_sync &&
(log->type->get_sync_count(log) == ms->nr_regions)) {
+ for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++) {
+ atomic_set(&m->error_count, 0);
+ m->error_type = 0;
+ }
/* the sync is complete */
dm_table_event(ms->ti->table);
ms->in_sync = 1;
@@ -1086,7 +1117,7 @@ static void write_callback(unsigned long
DMERR("All replicated volumes dead, failing I/O");
/* None of the writes succeeded, fail the I/O. */
ret = -EIO;
- } else if (errors_handled(ms)) {
+ } else if (handle_all_errors(ms)) {
/*
* Need to raise event. Since raising
* events can block, we need to do it in
@@ -1139,6 +1170,13 @@ static void do_writes(struct mirror_set
if (!writes->head)
return;
+
+ if (ms->write_blocked) {
+ spin_lock_irq(&ms->lock);
+ bio_list_merge(&ms->writes, writes);
+ spin_unlock_irq(&ms->lock);
+ return;
+ }
/*
* Classify each write.
@@ -1202,6 +1240,13 @@ static void do_failures(struct mirror_se
if (!failures->head)
return;
+
+ if (ms->write_blocked) {
+ spin_lock_irq(&ms->lock);
+ bio_list_merge(&ms->failures, failures);
+ spin_unlock_irq(&ms->lock);
+ return;
+ }
if (!ms->log_failure) {
while ((bio = bio_list_pop(failures)))
@@ -1297,7 +1342,6 @@ static void do_mirror(struct work_struct
schedule();
}
-
/*-----------------------------------------------------------------
* Target functions
*---------------------------------------------------------------*/
@@ -1327,6 +1371,7 @@ static struct mirror_set *alloc_context(
ms->nr_regions = dm_sector_div_up(ti->len, region_size);
ms->in_sync = 0;
ms->log_failure = 0;
+ ms->write_blocked = 0;
atomic_set(&ms->suspend, 0);
atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
@@ -1448,6 +1493,7 @@ static int parse_features(struct mirror_
{
unsigned num_features;
struct dm_target *ti = ms->ti;
+ int i;
*args_used = 0;
@@ -1458,24 +1504,25 @@ static int parse_features(struct mirror_
ti->error = "Invalid number of features";
return -EINVAL;
}
+ argv++, argc--;
- argc--;
- argv++;
- (*args_used)++;
-
- if (num_features > argc) {
+ if (argc < num_features) {
ti->error = "Not enough arguments to support feature count";
return -EINVAL;
}
- if (!strcmp("handle_errors", argv[0]))
- ms->features |= DM_RAID1_HANDLE_ERRORS;
- else {
- ti->error = "Unrecognised feature requested";
- return -EINVAL;
+ for (i = 0; i < num_features; i++) {
+ if (!strcmp("handle_errors", argv[i]))
+ ms->features |= DM_RAID1_HANDLE_ERRORS;
+ else if (!strcmp("block_on_error", argv[i]))
+ ms->features |= DM_RAID1_BLOCK_ON_ERROR;
+ else {
+ ti->error = "Unrecognised feature requested";
+ return -EINVAL;
+ }
}
- (*args_used)++;
+ *args_used = 1 + num_features;
return 0;
}
@@ -1789,6 +1836,7 @@ static void mirror_resume(struct dm_targ
*
* We return one character representing the most severe error
* we have encountered.
+ * M => Master - Has the latest data, can serve as a mirror Master
* 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
@@ -1798,6 +1846,14 @@ static void mirror_resume(struct dm_targ
*/
static char device_status_char(struct mirror *m)
{
+ struct mirror_set *ms = m->ms;
+
+ if (block_on_error(ms)) {
+ if (atomic_read(&m->error_count) == 0 &&
+ (ms->in_sync || get_default_mirror(ms) == m))
+ return 'M';
+ }
+
if (!atomic_read(&(m->error_count)))
return 'A';
@@ -1840,10 +1896,73 @@ static int mirror_status(struct dm_targe
DMEMIT(" %s %llu", ms->mirror[m].dev->name,
(unsigned long long)ms->mirror[m].offset);
- if (ms->features & DM_RAID1_HANDLE_ERRORS)
+ if (errors_handled(ms) && block_on_error(ms))
+ DMEMIT(" 2 handle_errors block_on_error");
+ else if (errors_handled(ms))
DMEMIT(" 1 handle_errors");
+ else if (block_on_error(ms))
+ DMEMIT(" 1 block_on_error");
}
+ return 0;
+}
+
+/* unblock message handler
+ *
+ * This message has the mirror device recorded states. If they don't
+ * agree to the actual state in the target, we regenerate uvent. If the
+ * recorded state and the actual of state of each device is same, we
+ * unblock the mirrorset to allow writes.
+ */
+static int mirror_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+ struct mirror_set *ms = (struct mirror_set *) ti->private;
+ char device_status;
+ char *name; /* major:minor format */
+ int i;
+
+ if (!block_on_error(ms))
+ return -EINVAL;
+ if (argc < 1 || strnicmp(argv[0], "unblock", sizeof("unblock")))
+ return -EINVAL;
+ argv++;
+ argc--;
+
+ spin_lock_irq(&ms->lock);
+ if (!ms->write_blocked)
+ DMWARN("Received unblock message when not blocked!");
+ if (argc != 2 * ms->nr_mirrors)
+ goto error;
+
+ for (i = 0; i < ms->nr_mirrors; i++) {
+ name = argv[2 * i];
+ if (strncmp(name, ms->mirror[i].dev->name,
+ sizeof(ms->mirror[i].dev->name))) {
+ DMWARN("name %s doesn't match name %s\n", name,
+ (ms->mirror[i].dev->name));
+ goto error;
+ }
+ if (sscanf(argv[2 * i + 1], "%c", &device_status) != 1) {
+ DMWARN("incorrect recorded state value");
+ goto error;
+ }
+
+ /* Re-generate uevent if the actual device state has
+ * changed since we last reported.
+ */
+ if (device_status != device_status_char(&ms->mirror[i]))
+ goto error;
+ }
+ ms->write_blocked = 0;
+ spin_unlock_irq(&ms->lock);
+ wake(ms);
+ return 0;
+
+error:
+ /* Regenerate the event */
+ spin_unlock_irq(&ms->lock);
+ dm_dev_uevent(DM_UEVENT_DEV_CHANGE, ms->ti);
+ schedule_work(&ms->trigger_event);
return 0;
}
@@ -1859,6 +1978,7 @@ static struct target_type mirror_target
.postsuspend = mirror_postsuspend,
.resume = mirror_resume,
.status = mirror_status,
+ .message = mirror_message,
};
static int __init dm_mirror_init(void)
diff -r bfb50ef53671 drivers/md/dm-uevent.c
--- a/drivers/md/dm-uevent.c Mon Mar 31 10:13:13 2008 -0700
+++ b/drivers/md/dm-uevent.c Tue Apr 01 16:09:09 2008 -0700
@@ -35,6 +35,7 @@ static const struct {
} _dm_uevent_type_names[] = {
{DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"},
{DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"},
+ {DM_UEVENT_DEV_CHANGE, KOBJ_CHANGE, "TARGET_STATE_CHANGE"},
};
static struct kmem_cache *_dm_event_cache;
@@ -111,6 +112,48 @@ static struct dm_uevent *dm_build_path_u
if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d",
nr_valid_paths)) {
DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed",
+ __func__);
+ goto err_add;
+ }
+
+ return event;
+
+err_add:
+ dm_uevent_free(event);
+err_nomem:
+ return ERR_PTR(-ENOMEM);
+}
+
+static struct dm_uevent *dm_build_dev_uevent(struct mapped_device *md,
+ struct dm_target *ti,
+ enum kobject_action action,
+ const char *dm_action)
+{
+ struct dm_uevent *event;
+
+ event = dm_uevent_alloc(md);
+ if (!event) {
+ DMERR("%s: dm_uevent_alloc() failed", __func__);
+ goto err_nomem;
+ }
+
+ event->action = action;
+
+ if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) {
+ DMERR("%s: add_uevent_var() for DM_TARGET failed",
+ __func__);
+ goto err_add;
+ }
+
+ if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) {
+ DMERR("%s: add_uevent_var() for DM_ACTION failed",
+ __func__);
+ goto err_add;
+ }
+
+ if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u",
+ dm_next_uevent_seq(md))) {
+ DMERR("%s: add_uevent_var() for DM_SEQNUM failed",
__func__);
goto err_add;
}
@@ -205,6 +248,36 @@ out:
}
EXPORT_SYMBOL_GPL(dm_path_uevent);
+/**
+ * dm_dev_uevent - called to create a new dev event and queue it
+ *
+ * @event_type: dev event type enum
+ * @ti: pointer to a dm_target
+ *
+ */
+void dm_dev_uevent(enum dm_uevent_type event_type, struct dm_target *ti)
+{
+ struct mapped_device *md = dm_table_get_md(ti->table);
+ struct dm_uevent *event;
+
+ if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) {
+ DMERR("%s: Invalid event_type %d", __func__, event_type);
+ goto out;
+ }
+
+ event = dm_build_dev_uevent(md, ti,
+ _dm_uevent_type_names[event_type].action,
+ _dm_uevent_type_names[event_type].name);
+ if (IS_ERR(event))
+ goto out;
+
+ dm_uevent_add(md, &event->elist);
+
+out:
+ dm_put(md);
+}
+EXPORT_SYMBOL_GPL(dm_dev_uevent);
+
int dm_uevent_init(void)
{
_dm_event_cache = KMEM_CACHE(dm_uevent, 0);
diff -r bfb50ef53671 drivers/md/dm-uevent.h
--- a/drivers/md/dm-uevent.h Mon Mar 31 10:13:13 2008 -0700
+++ b/drivers/md/dm-uevent.h Tue Apr 01 16:09:09 2008 -0700
@@ -24,6 +24,7 @@ enum dm_uevent_type {
enum dm_uevent_type {
DM_UEVENT_PATH_FAILED,
DM_UEVENT_PATH_REINSTATED,
+ DM_UEVENT_DEV_CHANGE,
};
#ifdef CONFIG_DM_UEVENT
@@ -34,6 +35,8 @@ extern void dm_path_uevent(enum dm_ueven
extern void dm_path_uevent(enum dm_uevent_type event_type,
struct dm_target *ti, const char *path,
unsigned nr_valid_paths);
+extern void dm_dev_uevent(enum dm_uevent_type event_type,
+ struct dm_target *ti);
#else
@@ -53,6 +56,10 @@ static inline void dm_path_uevent(enum d
unsigned nr_valid_paths)
{
}
+static inline void dm_dev_uevent(enum dm_uevent_type event_type,
+ struct dm_target *ti)
+{
+}
#endif /* CONFIG_DM_UEVENT */
--
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