Commit 85f5a4d6 authored by Ilya Dryomov's avatar Ilya Dryomov

rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set

There is a window between when RBD_DEV_FLAG_REMOVING is set and when
the device is removed from rbd_dev_list.  During this window, we set
"already" and return 0.

Returning 0 from write(2) can confuse userspace tools because
0 indicates that nothing was written.  In particular, "rbd unmap"
will retry the write multiple times a second:

  10:28:05.463299 write(4, "0", 1)        = 0
  10:28:05.463509 write(4, "0", 1)        = 0
  10:28:05.463720 write(4, "0", 1)        = 0
  10:28:05.463942 write(4, "0", 1)        = 0
  10:28:05.464155 write(4, "0", 1)        = 0

Cc: stable@vger.kernel.org
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Tested-by: default avatarDongsheng Yang <dongsheng.yang@easystack.cn>
parent c64a2b05
......@@ -5986,7 +5986,6 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
struct list_head *tmp;
int dev_id;
char opt_buf[6];
bool already = false;
bool force = false;
int ret;
......@@ -6019,13 +6018,13 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
spin_lock_irq(&rbd_dev->lock);
if (rbd_dev->open_count && !force)
ret = -EBUSY;
else
already = test_and_set_bit(RBD_DEV_FLAG_REMOVING,
&rbd_dev->flags);
else if (test_and_set_bit(RBD_DEV_FLAG_REMOVING,
&rbd_dev->flags))
ret = -EINPROGRESS;
spin_unlock_irq(&rbd_dev->lock);
}
spin_unlock(&rbd_dev_list_lock);
if (ret < 0 || already)
if (ret)
return ret;
if (force) {
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment