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authorIlya Dryomov <idryomov@gmail.com>2019-01-08 19:47:38 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-16 22:03:25 +0100
commitf3e9ba4c1b5ddcdd4dabaf3c977b51163eb3bff3 (patch)
treecb9cc9e626cb1304a15e7b5c607a3610087c20df
parent513bbaffa81ea0fb2b10744ff39da7cc6967e877 (diff)
rbd: don't return 0 on unmap if RBD_DEV_FLAG_REMOVING is set
commit 85f5a4d666fd9be73856ed16bb36c5af5b406b29 upstream. 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: Ilya Dryomov <idryomov@gmail.com> Tested-by: Dongsheng Yang <dongsheng.yang@easystack.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/block/rbd.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 8e5140bbf241..1e92b61d0bd5 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -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) {