Messages in this thread | | | Date | Sun, 28 Feb 2010 19:48:43 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH] relay: move remove_buf_file inside relay_close_buf |
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On Sat, Feb 27 2010, Dmitry Monakhov wrote: > 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) > > 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. > > We don't have to wait this long. File may be deleted > inside relay_close_buf().
Thanks, I believe this fixes a long standing problem we've had with blktrace. You can add my acked-by.
-- Jens Axboe
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