Xiubo Li
ff9edf3f77
[ Upstream commit 862488105b ]
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: Mike Christie <mchristi@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.