linux-ext4 - Help! How to delete an 8094-byte PATH?

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Message-ID: <d4a67b38-3026-59be-06a8-3a9a5f908eb4@embecosm.com>
Date:   Thu, 27 Jan 2022 07:06:51 +0000
From:   Maxim Blinov <maxim.blinov@...ecosm.com>
To:     linux-ext4@...r.kernel.org
Subject: Help! How to delete an 8094-byte PATH?

Hi all,

I'm not a subscriber to this list (so please put me in the CC), but I've
hit a really annoying un-googleable issue that I don't know who to ask
about.

A runaway script has been recursively creating sub-directories under
sub-directories until it hit the (apparent) OS limit. The path in
question goes something like this:

/work/build-native/binutils-gdb/gnulib/confdir3/confdir3/confdir3/confdir3/confdir3/........
(you get the idea)

It was only stopped by the following error:
mkdir: cannot create directory 'confdir3': File name too long

OK, fine, that was silly but whatever, right? I tried to delete this
huge directory from the top with

rm -rf confdir3/

but that simply generated the same error as above. So, I figured "Hey,
I'll just walk all the way to the bottom, and delete the directories
one-by-one bottom up". Here's the script I ran to get to the bottom:

$ for i in $(seq 999999); do echo "im $i levels deep"; cd confdir3; done;

It then ran for a while, and eventually I got to the bottom:

```
...
im 892 levels deep
im 893 levels deep
im 894 levels deep
im 895 levels deep
im 896 levels deep
bash: cd: confdir3: File name too long
$ ls
<nothing here>
```

So then, I `cd ../`, and `rmdir confdir3`, but even here, I get

rmdir: failed to remove 'confdir3/': File name too long

I would be very grateful if someone could please help suggest how I
might get this infernal tower of directories off of my precious ext4
partition.

I was thinking maybe there's some kind of magic "forget this directory
inode ever existed" command, but I am out of my depth with filesystems.

Best Regards,

Maxim Blinov