On linux with python lib, when using mkdir -p, does not capture child folder creations

[yufei-pan]

mkdir -p tfp/new

only one event got generated
{"effect_time":1738138437295141641,"path_name":".../test/tfp","associated_path_name":null,"effect_type":"create","path_type":"dir"}

This maybe a limit of underlying inotify ?

I am on 6.12.10-200.fc41.x86_64

[e-dant]

I'm pretty sure that we're not adding a mark on that first directory quickly enough to receive the second event.

If there was an error watching new directories, we'd shoot a warning up and tell you. It looks like we just didn't notice.

Ideally we should write the watcher in such a way that avoids the race altogether.

[e-dant]

We do notice destroy events on the nested path, though those events are tied to the first path, so not much of a surprise.

$ ( wtr.watcher /tmp -ms 1000 | grep -v self | jq -c '. | {(.path_name): .effect_type}' ) & ( cd /tmp ; sleep 0.1 ; mkdir -p a/b ; rmdir a/b a )
{"/tmp/a":"create"}
{"/tmp/a/b":"destroy"}
{"/tmp/a":"destroy"}

[e-dant]

f4aaf62 should fix this.

[e-dant]

For fanotify, things get a bit weird. It "works", but:

{"path_type":"dir","path_name":"/tmp/a","effect_type":"create","effect_time":1738444397609015400,"associated":null}
{"path_type":"dir","path_name":"/tmp/a/b","effect_type":"create","effect_time":1738444397609122077,"associated":null}
{"path_type":"dir","path_name":"/tmp/a (deleted)/b","effect_type":"destroy","effect_time":1738444397610121378,"associated":null}
{"path_type":"dir","path_name":"/tmp/a","effect_type":"destroy","effect_time":1738444397610169432,"associated":null}

We get some weird "/tmp/a (deleted)/b" action there. The "(deleted)" part is just something fanotify decided to add all by itself.

[e-dant]

For fanotify, things get a bit weird. It "works", but...

Can't perfectly reproduce the behavior. I didn't write the kernel's fanotify implementation, but maybe if someone more versed in it could explain when that path is concatenated with extra metadata, and when it is not, that would be nice. Seems a bit weird.