Searched hist:b8d4a5bf6a049303a29a3275f463f09a490b50ea (Results 1 – 1 of 1) sorted by relevance
/linux/kernel/ |
H A D | relay.c | diff b8d4a5bf6a049303a29a3275f463f09a490b50ea Mon Apr 22 09:41:41 CEST 2013 Dmitry Monakhov <dmonakhov@openvz.org> 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>
|