This mirrors what we already do during allocation. We lock the control
device first, and then release the block device and then delete it.
This makes things substantially more robust as long all participants do
such locking: we won't attempt to delete a block device somebody else
already is using.
Back when I wrote this code I wasn't aware of BLKPG and what it can do.
Hence I came up with this hack to attach an empty file to delete all
partitions. But today we can do better with BLKPG: let's just explicitly
remove all partitions, and then try again.
Let's rework how we lock loopback block devices in two ways:
1. Lock a separate fd, instead of the main block device fd. We already
did that for our internal locking when allocating loopback block
devices, but do so for the exposed locking (i.e.
loop_device_flock()), too, so that the lock is independent of the
main fd we actually use of IO.
2. Instead of locking the device during allocation of the loopback
device, then unlocking it (which will make udev run), and then
re-locking things if we need, let's instead just keep the lock the
whole time, to make things a bit safer and faster, and not have to
wait for udev at all. This is done by adding a "lock_op" parameter to
loop device allocation functions that declares the initial state of
the lock, and is one of LOCK_UN/LOCK_SH/LOCK_EX. This change also
shortens a lot of code, since we allocate + immediately lock loopback
devices pretty much everywhere.
This reverts a major chunk of 75d7e04eb4
Now that the loopback device code already destroys the partitions we
don't have to do this here anymore.
I am sure the right place to delete the partitions is in the loopback
code, since we really only should do that for loopback devices, see
bug #24431, and not on "real" block devices.
I am also not convinced dropping partitions the dissection logic doesn't
care about is a good idea, after all. The dissection stuff should
probably not consider itself the "owner" of the block devices it
analyzes, but take a more passive role: figure out what is what, but not
modify it.
Fixes: #24431
Whenever we release a loopback device, let's first synchronously delete
all partitions, so that we know that's complete and not done
asynchronously in the background. Take a BSD lock on the device while
doing so, so that udev won't make the devices busy while we do this.
Often I end up debugging a problem on a system, and I
do e.g. `journalctl --grep=failed|error`. The use of the term
"failed" for condition checks adds a *lot* of unnecessary noise into
this.
Now, I know this regexp search isn't precise, but it has proven
to be useful to me.
I think "failed" is too strong of a term as a baseline, and also
just stands out to e.g. humans watching their servers boot or
whatever.
The term "met condition" is fairly widely used, e.g.
https://stackoverflow.com/questions/63751794/what-does-the-condition-is-met-exactly-mean-in-programming-languages
Use that instead.
Unfortunately, hex output can only be produced with unsigned types. Some
cases can be fixed by producing the correct type, but a few simply have
to be cast. At least casting makes it explicit.
The key doesn't create a release event. This is a fix to make it work properly. I made sure the product is generic to work on all Victus laptops.
This fix#23006.
Luca Boccassi
Lennart Poettering
Yu Watanabe
Antonio Alvarez Feijoo
dependabot[bot]
Colin Walters
Frantisek Sumsal
Jan Janssen
Swapnil Devesh
LockBlock-dev