dm: keep old table until after resume succeeded
When swapping a new table into place, retain the old table until
its replacement is in place.
An old check for an empty table is removed because this is enforced
in populate_table().
__unbind() becomes redundant when followed by __bind().
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index a3d2026..63fd4de 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -855,7 +855,7 @@
unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
struct hash_cell *hc;
struct mapped_device *md;
- struct dm_table *new_map;
+ struct dm_table *new_map, *old_map = NULL;
down_write(&_hash_lock);
@@ -884,11 +884,11 @@
if (!dm_suspended(md))
dm_suspend(md, suspend_flags);
- r = dm_swap_table(md, new_map);
- if (r) {
+ old_map = dm_swap_table(md, new_map);
+ if (IS_ERR(old_map)) {
dm_table_destroy(new_map);
dm_put(md);
- return r;
+ return PTR_ERR(old_map);
}
if (dm_table_get_mode(new_map) & FMODE_WRITE)
@@ -900,6 +900,8 @@
if (dm_suspended(md))
r = dm_resume(md);
+ if (old_map)
+ dm_table_destroy(old_map);
if (!r) {
dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 255b75c..c254c6c 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2033,9 +2033,13 @@
mutex_unlock(&md->bdev->bd_inode->i_mutex);
}
-static int __bind(struct mapped_device *md, struct dm_table *t,
- struct queue_limits *limits)
+/*
+ * Returns old map, which caller must destroy.
+ */
+static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
+ struct queue_limits *limits)
{
+ struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
unsigned long flags;
@@ -2050,11 +2054,6 @@
__set_size(md, size);
- if (!size) {
- dm_table_destroy(t);
- return 0;
- }
-
dm_table_event_callback(t, event_callback, md);
/*
@@ -2070,11 +2069,12 @@
__bind_mempools(md, t);
write_lock_irqsave(&md->map_lock, flags);
+ old_map = md->map;
md->map = t;
dm_table_set_restrictions(t, q, limits);
write_unlock_irqrestore(&md->map_lock, flags);
- return 0;
+ return old_map;
}
/*
@@ -2368,13 +2368,13 @@
}
/*
- * Swap in a new table (destroying old one).
+ * Swap in a new table, returning the old one for the caller to destroy.
*/
-int dm_swap_table(struct mapped_device *md, struct dm_table *table)
+struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
- struct dm_table *map;
+ struct dm_table *map = ERR_PTR(-EINVAL);
struct queue_limits limits;
- int r = -EINVAL;
+ int r;
mutex_lock(&md->suspend_lock);
@@ -2383,8 +2383,10 @@
goto out;
r = dm_calculate_queue_limits(table, &limits);
- if (r)
+ if (r) {
+ map = ERR_PTR(r);
goto out;
+ }
/* cannot change the device type, once a table is bound */
if (md->map &&
@@ -2393,13 +2395,11 @@
goto out;
}
- map = __unbind(md);
- r = __bind(md, table, &limits);
- dm_table_destroy(map);
+ map = __bind(md, table, &limits);
out:
mutex_unlock(&md->suspend_lock);
- return r;
+ return map;
}
/*
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index fc16a35..b9c6c8c 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -295,8 +295,10 @@
/*
* The device must be suspended before calling this method.
+ * Returns the previous table, which the caller must destroy.
*/
-int dm_swap_table(struct mapped_device *md, struct dm_table *t);
+struct dm_table *dm_swap_table(struct mapped_device *md,
+ struct dm_table *t);
/*
* A wrapper around vmalloc.