When a table is dropped, we delete its sstables, and finally try to delete
the table's top-level directory with the rmdir system call. When the
auto-snapshot feature is enabled (this is still Scylla's default),
the snapshot will remain in that directory so it won't be empty and will
cannot be removed. Today, this results in a long, ugly and scary warning
in the log:
```
WARN 2023-07-06 20:48:04,995 [shard 0] sstable - Could not remove table directory "/tmp/scylla-test-198265/data/alternator_alternator_Test_1688665684546/alternator_Test_1688665684546-4238f2201c2511eeb15859c589d9be4d/snapshots": std::filesystem::__cxx11::filesystem_error (error system:39, filesystem error: remove failed: Directory not empty [/tmp/scylla-test-198265/data/alternator_alternator_Test_1688665684546/alternator_Test_1688665684546-4238f2201c2511eeb15859c589d9be4d/snapshots]). Ignored.
```
It is bad to log as a warning something which is completely normal - it
happens every time a table is dropped with the perfectly valid (and even
default) auto-snapshot mode. We should only log a warning if the deletion
failed because of some unexpected reason.
And in fact, this is exactly what the code **tried** to do - it does
not log a warning if the rmdir failed with EEXIST. It even had a comment
saying why it was doing this. But the problem is that in Linux, deleting
a non-empty directory does not return EEXIST, it returns ENOTEMPTY...
Posix actually allows both. So we need to check both, and this is the
only change in this patch.
To confirm this that this patch works, edit test/cql-pytest/run.py and
change auto-snapshot from 0 to 1, run test/alternator/run (for example)
and see many "Directory not empty" warnings as above. With this patch,
none of these warnings appear.
Fixes#13538
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#14557
edfb89ef65