Commit 86248810 authored by Xiubo Li's avatar Xiubo Li Committed by Jens Axboe

nbd: fix possible sysfs duplicate warning

1. nbd_put takes the mutex and drops nbd->ref to 0. It then does
idr_remove and drops the mutex.

2. nbd_genl_connect takes the mutex. idr_find/idr_for_each fails
to find an existing device, so it does nbd_dev_add.

3. just before the nbd_put could call nbd_dev_remove or not finished
totally, but if nbd_dev_add try to add_disk, we can hit:

debugfs: Directory 'nbd1' with parent 'block' already present!

This patch will make sure all the disk add/remove stuff are done
by holding the nbd_index_mutex lock.
Reported-by: default avatarMike Christie <mchristi@redhat.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarXiubo Li <xiubli@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 79a85e21
...@@ -248,8 +248,8 @@ static void nbd_put(struct nbd_device *nbd) ...@@ -248,8 +248,8 @@ static void nbd_put(struct nbd_device *nbd)
if (refcount_dec_and_mutex_lock(&nbd->refs, if (refcount_dec_and_mutex_lock(&nbd->refs,
&nbd_index_mutex)) { &nbd_index_mutex)) {
idr_remove(&nbd_index_idr, nbd->index); idr_remove(&nbd_index_idr, nbd->index);
mutex_unlock(&nbd_index_mutex);
nbd_dev_remove(nbd); nbd_dev_remove(nbd);
mutex_unlock(&nbd_index_mutex);
} }
} }
......
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