On 11/16/2012 07:43 AM, Alex Elder wrote:
There is no check in rbd_remove() to see if anybody holds ope the
image being removed. That's not cool.
Add a simple open count that goes up and down with opens and closes
(releases) of the device, and don't allow an rbd image to be removed
if the count is non-zero. Both functions are protected by the
bd_mutex so there's no need for any other concurrency protection.
Signed-off-by: Alex Elder <[email protected]>
---
drivers/block/rbd.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index fba0822..9d9a2f3 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -255,6 +255,7 @@ struct rbd_device {
/* sysfs related */
struct device dev;
+ unsigned long open_count;
};
static DEFINE_MUTEX(ctl_mutex); /* Serialize
open/close/setup/teardown */
@@ -358,6 +359,7 @@ static int rbd_open(struct block_device *bdev,
fmode_t mode)
rbd_get_dev(rbd_dev);
set_device_ro(bdev, rbd_dev->mapping.read_only);
+ rbd_dev->open_count++;
return 0;
}
@@ -366,6 +368,8 @@ static int rbd_release(struct gendisk *disk, fmode_t
mode)
{
struct rbd_device *rbd_dev = disk->private_data;
+ rbd_assert(rbd_dev->open_count > 0);
+ rbd_dev->open_count--;
rbd_put_dev(rbd_dev);
return 0;
@@ -3764,6 +3768,11 @@ static ssize_t rbd_remove(struct bus_type *bus,
goto done;
}
+ if (rbd_dev->open_count) {
+ ret = -EBUSY;
+ goto done;
+ }
+
Is this protected by bd_mutex?
rbd_remove_all_snaps(rbd_dev);
rbd_bus_del_dev(rbd_dev);
--
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