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author | Dmitry Monakhov <dmonakhov@openvz.org> | 2013-04-22 07:41:41 (GMT) |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2013-04-30 11:00:02 (GMT) |
commit | b8d4a5bf6a049303a29a3275f463f09a490b50ea (patch) | |
tree | c9a87f8a6eb8a64d0c5b8304c80bc2c22407289c | |
parent | ea56505bedd03e21f497c59cece15a62b4398fc4 (diff) | |
download | linux-b8d4a5bf6a049303a29a3275f463f09a490b50ea.tar.xz |
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>
-rw-r--r-- | kernel/relay.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/relay.c b/kernel/relay.c index 01ab081..a0d2000 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -234,7 +234,6 @@ static void relay_destroy_buf(struct rchan_buf *buf) static void relay_remove_buf(struct kref *kref) { struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref); - buf->chan->cb->remove_buf_file(buf->dentry); relay_destroy_buf(buf); } @@ -484,6 +483,7 @@ static void relay_close_buf(struct rchan_buf *buf) { buf->finalized = 1; del_timer_sync(&buf->timer); + buf->chan->cb->remove_buf_file(buf->dentry); kref_put(&buf->kref, relay_remove_buf); } |