relay: move remove_buf_file inside relay_close_buf
Currently remove_buf_file callback is called from from kobject
release method. This result in follow issue:
# blktrace -d /dev/sda1 -d /dev/sda -o test
blktrace_setup()
dir = create_dir()
rchan = relay_open(dir,...)
->create_buf_file_callback
buf_file = debugfs_create_file(dir, )
Userspace will open buf_file.
Later we make a decision to stop tracing
blktrace_down()
relay_close(rhcan) /* just decrement kobj reference */
/* since it is not zero then callback not called */
debugfs_remove(dir) /* FAIL due to non empty dir */
Later user space will close the file and file will be deleted,
but directory still exist.
user_space_close()
->file_release
->release_buf_file_callback
->debugfs_remove(buf_file
## TESTCASE:
# blktrace -d /dev/sda1 -d /dev/sda -o test
# After that blktrace infrastructure will remain broken in
# an unusable state so: blktrace -d /dev/sda1 will not work.
In fact this is general issue, blktrace is just one of examples.
We can not reliably remove parent dir until all users close the
buf_file.
Solution: We don't have to wait that long. File should be deleted inside
relay_close_buf().
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed