/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
+#include <linux/delay.h>
#include <asm/atomic.h>
#define DM_MSG_PREFIX "table"
#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
+/*
+ * The table has always exactly one reference from either mapped_device->map
+ * or hash_cell->new_map. This reference is not counted in table->holders.
+ * A pair of dm_create_table/dm_destroy_table functions is used for table
+ * creation/destruction.
+ *
+ * Temporary references from the other code increase table->holders. A pair
+ * of dm_table_get/dm_table_put functions is used to manipulate it.
+ *
+ * When the table is about to be destroyed, we wait for table->holders to
+ * drop to zero.
+ */
+
struct dm_table {
struct mapped_device *md;
atomic_t holders;
sector_t *highs;
struct dm_target *targets;
+ unsigned barriers_supported:1;
+
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
* and FMODE_WRITE.
*/
- int mode;
+ fmode_t mode;
/* a list of devices used by this table */
struct list_head devices;
return 0;
}
-int dm_table_create(struct dm_table **result, int mode,
+int dm_table_create(struct dm_table **result, fmode_t mode,
unsigned num_targets, struct mapped_device *md)
{
struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
return -ENOMEM;
INIT_LIST_HEAD(&t->devices);
- atomic_set(&t->holders, 1);
+ atomic_set(&t->holders, 0);
+ t->barriers_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
}
}
-static void table_destroy(struct dm_table *t)
+void dm_table_destroy(struct dm_table *t)
{
unsigned int i;
+ while (atomic_read(&t->holders))
+ msleep(1);
+ smp_mb();
+
/* free the indexes (see dm_table_complete) */
if (t->depth >= 2)
vfree(t->index[t->depth - 2]);
if (!t)
return;
- if (atomic_dec_and_test(&t->holders))
- table_destroy(t);
+ smp_mb__before_atomic_dec();
+ atomic_dec(&t->holders);
}
/*
}
/*
- * Convert a device path to a dev_t.
- */
-static int lookup_device(const char *path, dev_t *dev)
-{
- struct block_device *bdev = lookup_bdev(path);
- if (IS_ERR(bdev))
- return PTR_ERR(bdev);
- *dev = bdev->bd_dev;
- bdput(bdev);
- return 0;
-}
-
-/*
* See if we've already got a device in the list.
*/
static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
return PTR_ERR(bdev);
r = bd_claim_by_disk(bdev, _claim_ptr, dm_disk(md));
if (r)
- blkdev_put(bdev);
+ blkdev_put(bdev, d->dm_dev.mode);
else
d->dm_dev.bdev = bdev;
return r;
return;
bd_release_from_disk(d->dm_dev.bdev, dm_disk(md));
- blkdev_put(d->dm_dev.bdev);
+ blkdev_put(d->dm_dev.bdev, d->dm_dev.mode);
d->dm_dev.bdev = NULL;
}
* careful to leave things as they were if we fail to reopen the
* device.
*/
-static int upgrade_mode(struct dm_dev_internal *dd, int new_mode,
+static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
struct mapped_device *md)
{
int r;
*/
static int __table_get_device(struct dm_table *t, struct dm_target *ti,
const char *path, sector_t start, sector_t len,
- int mode, struct dm_dev **result)
+ fmode_t mode, struct dm_dev **result)
{
int r;
dev_t uninitialized_var(dev);
return -EOVERFLOW;
} else {
/* convert the path to a device */
- if ((r = lookup_device(path, &dev)))
- return r;
+ struct block_device *bdev = lookup_bdev(path);
+
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+ dev = bdev->bd_dev;
+ bdput(bdev);
}
dd = find_device(&t->devices, dev);
{
struct request_queue *q = bdev_get_queue(bdev);
struct io_restrictions *rs = &ti->limits;
+ char b[BDEVNAME_SIZE];
+
+ if (unlikely(!q)) {
+ DMWARN("%s: Cannot set limits for nonexistent device %s",
+ dm_device_name(ti->table->md), bdevname(bdev, b));
+ return;
+ }
/*
* Combine the device limits low.
EXPORT_SYMBOL_GPL(dm_set_device_limits);
int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
- sector_t len, int mode, struct dm_dev **result)
+ sector_t len, fmode_t mode, struct dm_dev **result)
{
int r = __table_get_device(ti->table, ti, path,
start, len, mode, result);
if (!rs->max_segment_size)
rs->max_segment_size = MAX_SEGMENT_SIZE;
if (!rs->seg_boundary_mask)
- rs->seg_boundary_mask = -1;
+ rs->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
if (!rs->bounce_pfn)
rs->bounce_pfn = -1;
}
/* FIXME: the plan is to combine high here and then have
* the merge fn apply the target level restrictions. */
combine_restrictions_low(&t->limits, &tgt->limits);
+
+ if (!(tgt->type->features & DM_TARGET_SUPPORTS_BARRIERS))
+ t->barriers_supported = 0;
+
return 0;
bad:
check_for_valid_limits(&t->limits);
+ /*
+ * We only support barriers if there is exactly one underlying device.
+ */
+ if (!list_is_singular(&t->devices))
+ t->barriers_supported = 0;
+
/* how many indexes will the btree have ? */
leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
return &t->devices;
}
-int dm_table_get_mode(struct dm_table *t)
+fmode_t dm_table_get_mode(struct dm_table *t)
{
return t->mode;
}
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
- r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+ char b[BDEVNAME_SIZE];
+
+ if (likely(q))
+ r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+ else
+ DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
+ dm_device_name(t->md),
+ bdevname(dd->dm_dev.bdev, b));
}
return r;
list_for_each_entry(dd, devices, list) {
struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
-
- blk_unplug(q);
+ char b[BDEVNAME_SIZE];
+
+ if (likely(q))
+ blk_unplug(q);
+ else
+ DMWARN_LIMIT("%s: Cannot unplug nonexistent device %s",
+ dm_device_name(t->md),
+ bdevname(dd->dm_dev.bdev, b));
}
}
return t->md;
}
+int dm_table_barrier_ok(struct dm_table *t)
+{
+ return t->barriers_supported;
+}
+EXPORT_SYMBOL(dm_table_barrier_ok);
+
EXPORT_SYMBOL(dm_vcalloc);
EXPORT_SYMBOL(dm_get_device);
EXPORT_SYMBOL(dm_put_device);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff