* This file is released under the GPL.
*/
-#include "dm.h"
+#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/log2.h>
#define DM_MSG_PREFIX "striped"
+#define DM_IO_ERROR_THRESHOLD 15
struct stripe {
struct dm_dev *dev;
sector_t physical_start;
+
+ atomic_t error_count;
};
struct stripe_c {
uint32_t chunk_shift;
sector_t chunk_mask;
+ /* Needed for handling events */
+ struct dm_target *ti;
+
+ /* Work struct used for triggering events*/
+ struct work_struct kstriped_ws;
+
struct stripe stripe[0];
};
+static struct workqueue_struct *kstriped;
+
+/*
+ * An event is triggered whenever a drive
+ * drops out of a stripe volume.
+ */
+static void trigger_event(struct work_struct *work)
+{
+ struct stripe_c *sc = container_of(work, struct stripe_c, kstriped_ws);
+
+ dm_table_event(sc->ti->table);
+
+}
+
static inline struct stripe_c *alloc_context(unsigned int stripes)
{
size_t len;
- if (array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
- stripes))
+ if (dm_array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
+ stripes))
return NULL;
len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
return -ENXIO;
sc->stripe[stripe].physical_start = start;
+
return 0;
}
return -ENOMEM;
}
+ INIT_WORK(&sc->kstriped_ws, trigger_event);
+
+ /* Set pointer to dm target; used in trigger_event */
+ sc->ti = ti;
+
sc->stripes = stripes;
sc->stripe_width = width;
ti->split_io = chunk_size;
+ ti->num_flush_requests = stripes;
sc->chunk_mask = ((sector_t) chunk_size) - 1;
for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
kfree(sc);
return r;
}
+ atomic_set(&(sc->stripe[i].error_count), 0);
}
ti->private = sc;
+
return 0;
}
for (i = 0; i < sc->stripes; i++)
dm_put_device(ti, sc->stripe[i].dev);
+ flush_workqueue(kstriped);
kfree(sc);
}
union map_info *map_context)
{
struct stripe_c *sc = (struct stripe_c *) ti->private;
+ sector_t offset, chunk;
+ uint32_t stripe;
- sector_t offset = bio->bi_sector - ti->begin;
- sector_t chunk = offset >> sc->chunk_shift;
- uint32_t stripe = sector_div(chunk, sc->stripes);
+ if (unlikely(bio_empty_barrier(bio))) {
+ BUG_ON(map_context->flush_request >= sc->stripes);
+ bio->bi_bdev = sc->stripe[map_context->flush_request].dev->bdev;
+ return DM_MAPIO_REMAPPED;
+ }
+
+ offset = bio->bi_sector - ti->begin;
+ chunk = offset >> sc->chunk_shift;
+ stripe = sector_div(chunk, sc->stripes);
bio->bi_bdev = sc->stripe[stripe].dev->bdev;
bio->bi_sector = sc->stripe[stripe].physical_start +
return DM_MAPIO_REMAPPED;
}
+/*
+ * Stripe status:
+ *
+ * INFO
+ * #stripes [stripe_name <stripe_name>] [group word count]
+ * [error count 'A|D' <error count 'A|D'>]
+ *
+ * TABLE
+ * #stripes [stripe chunk size]
+ * [stripe_name physical_start <stripe_name physical_start>]
+ *
+ */
+
static int stripe_status(struct dm_target *ti,
status_type_t type, char *result, unsigned int maxlen)
{
struct stripe_c *sc = (struct stripe_c *) ti->private;
+ char buffer[sc->stripes + 1];
unsigned int sz = 0;
unsigned int i;
switch (type) {
case STATUSTYPE_INFO:
- result[0] = '\0';
+ DMEMIT("%d ", sc->stripes);
+ for (i = 0; i < sc->stripes; i++) {
+ DMEMIT("%s ", sc->stripe[i].dev->name);
+ buffer[i] = atomic_read(&(sc->stripe[i].error_count)) ?
+ 'D' : 'A';
+ }
+ buffer[i] = '\0';
+ DMEMIT("1 %s", buffer);
break;
case STATUSTYPE_TABLE:
return 0;
}
+static int stripe_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ unsigned i;
+ char major_minor[16];
+ struct stripe_c *sc = ti->private;
+
+ if (!error)
+ return 0; /* I/O complete */
+
+ if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
+ return error;
+
+ if (error == -EOPNOTSUPP)
+ return error;
+
+ memset(major_minor, 0, sizeof(major_minor));
+ sprintf(major_minor, "%d:%d",
+ MAJOR(disk_devt(bio->bi_bdev->bd_disk)),
+ MINOR(disk_devt(bio->bi_bdev->bd_disk)));
+
+ /*
+ * Test to see which stripe drive triggered the event
+ * and increment error count for all stripes on that device.
+ * If the error count for a given device exceeds the threshold
+ * value we will no longer trigger any further events.
+ */
+ for (i = 0; i < sc->stripes; i++)
+ if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
+ atomic_inc(&(sc->stripe[i].error_count));
+ if (atomic_read(&(sc->stripe[i].error_count)) <
+ DM_IO_ERROR_THRESHOLD)
+ queue_work(kstriped, &sc->kstriped_ws);
+ }
+
+ return error;
+}
+
+static int stripe_iterate_devices(struct dm_target *ti,
+ iterate_devices_callout_fn fn, void *data)
+{
+ struct stripe_c *sc = ti->private;
+ int ret = 0;
+ unsigned i = 0;
+
+ do
+ ret = fn(ti, sc->stripe[i].dev,
+ sc->stripe[i].physical_start, data);
+ while (!ret && ++i < sc->stripes);
+
+ return ret;
+}
+
static struct target_type stripe_target = {
.name = "striped",
- .version= {1, 0, 2},
+ .version = {1, 2, 0},
.module = THIS_MODULE,
.ctr = stripe_ctr,
.dtr = stripe_dtr,
.map = stripe_map,
+ .end_io = stripe_end_io,
.status = stripe_status,
+ .iterate_devices = stripe_iterate_devices,
};
int __init dm_stripe_init(void)
int r;
r = dm_register_target(&stripe_target);
- if (r < 0)
+ if (r < 0) {
DMWARN("target registration failed");
+ return r;
+ }
+
+ kstriped = create_singlethread_workqueue("kstriped");
+ if (!kstriped) {
+ DMERR("failed to create workqueue kstriped");
+ dm_unregister_target(&stripe_target);
+ return -ENOMEM;
+ }
return r;
}
void dm_stripe_exit(void)
{
- if (dm_unregister_target(&stripe_target))
- DMWARN("target unregistration failed");
+ dm_unregister_target(&stripe_target);
+ destroy_workqueue(kstriped);
return;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff