tree 2e03d9e6e1d75a8558610fcee226f6e1f9fe6fc4
parent 90e98c5229c0adfadf2c2ad2c91d72902bf61bc4
author Josh Durgin <josh.durgin@inktank.com> 1396638392 -0700
committer Ilya Dryomov <idryomov@redhat.com> 1413306212 +0400

rbd: read image size for discard check safely

In rbd_img_request_fill() the image size is only checked to determine
whether we can truncate an object instead of zeroing it for discard
requests. Take rbd_dev->header_rwsem while reading the image size, and
move this read into the discard check, so that non-discard ops don't
need to take the semaphore in this function.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>