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rbd: set removing flag while holding list lock

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When unmapping a device, its id is supplied, and that is used to
look up which rbd device should be unmapped.  Looking up the
device involves searching the rbd device list while holding
a spinlock that protects access to that list.

Currently all of this is done under protection of the control lock,
but that protection is going away soon.  To ensure the rbd_dev is
still valid (still on the list) while setting its REMOVING flag, do
so while still holding the list lock.  To do so, get rid of
__rbd_get_dev(), and open code what it did in the one place it
was used.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-05-31 15:17:01 -05:00 committed by Sage Weil
parent 4974341eb9
commit 751cc0e3cf
1 changed files with 22 additions and 31 deletions
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53
drivers/block/rbd.c
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@ -5090,23 +5090,6 @@ static ssize_t rbd_add(struct bus_type *bus,
return (ssize_t)rc;
}
static struct rbd_device *__rbd_get_dev(unsigned long dev_id)
{
struct list_head *tmp;
struct rbd_device *rbd_dev;
spin_lock(&rbd_dev_list_lock);
list_for_each(tmp, &rbd_dev_list) {
rbd_dev = list_entry(tmp, struct rbd_device, node);
if (rbd_dev->dev_id == dev_id) {
spin_unlock(&rbd_dev_list_lock);
return rbd_dev;
}
}
spin_unlock(&rbd_dev_list_lock);
return NULL;
}
static void rbd_dev_device_release(struct device *dev)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
@ -5151,7 +5134,8 @@ static ssize_t rbd_remove(struct bus_type *bus,
size_t count)
{
struct rbd_device *rbd_dev = NULL;
int target_id;
struct list_head *tmp;
int dev_id;
unsigned long ul;
int ret;
@ -5160,26 +5144,33 @@ static ssize_t rbd_remove(struct bus_type *bus,
return ret;
/* convert to int; abort if we lost anything in the conversion */
target_id = (int) ul;
if (target_id != ul)
dev_id = (int)ul;
if (dev_id != ul)
return -EINVAL;
mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
rbd_dev = __rbd_get_dev(target_id);
if (!rbd_dev) {
ret = -ENOENT;
goto done;
ret = -ENOENT;
spin_lock(&rbd_dev_list_lock);
list_for_each(tmp, &rbd_dev_list) {
rbd_dev = list_entry(tmp, struct rbd_device, node);
if (rbd_dev->dev_id == dev_id) {
ret = 0;
break;
}
}
spin_lock_irq(&rbd_dev->lock);
if (rbd_dev->open_count)
ret = -EBUSY;
else
set_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags);
spin_unlock_irq(&rbd_dev->lock);
if (!ret) {
spin_lock_irq(&rbd_dev->lock);
if (rbd_dev->open_count)
ret = -EBUSY;
else
set_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags);
spin_unlock_irq(&rbd_dev->lock);
}
spin_unlock(&rbd_dev_list_lock);
if (ret < 0)
goto done;
rbd_bus_del_dev(rbd_dev);
ret = rbd_dev_header_watch_sync(rbd_dev, false);
if (ret)