https://learn.microsoft.com/en-us/windows/win32/fileio/about...
In some other cases, I've used a pattern where I used a symlink to folders. The symlink is created, resolved or updated atomically, and all I need is eventual consistency.
That last case was to manage several APT repository indices. The indices were constantly updated to publish new testing or unstable releases of software and machines in the fleet were regularly fetching the repository index. The APT protocol and structure being a bit "dumb" (for better or worse) requires you to fetch files (many of them) in the reverse order they are created, which leads to obvious issues like the signature is updated only after the list of files is updated, or the list of files is created only after the list of packages is created.
Long story short, each update would create a new folder that's consistent, and a symlink points to the last created folder (to atomically replace the folder as it was not possible to swap them), and a small HTTP server would initiate a server side session when the first file is fetched and only return files from the same index list, and everything is eventually consistent, and we never get APT complaining about having signature or hash mismatches. The pivotal component was indeed the atomicity of having a symlink to deal with it, as the Java implementation didn't have access to a more modern "openat" syscall, relative to a specific folder.
mv a b
mv c d
If that's not what you're saying, could you give an example of something you want to be able to do but can't?
You can remedy 2) by doing fsync() on the parent directory in between. I just asked ChatGPT which directory you need to fsync. It says it's both, the source and the target directory. Which "makes sense" and simplifies implementations, but it means the rename operation is atomic only at runtime, not if there's a crash in between. It think you might end up with 0 or 2 entries after a crash if you're unlucky.
If that's true, then for safety maybe one should never rename across directories, but instead do a coordinated link(source, target), fsync(target_dir), unlink(source), fsync(source_dir)
As to whether it’s technically possible for it to happen on a system that stays on, I’m not sure, but it’s certainly vanishingly rare and likely requires very specific circumstances—not just a random race condition.
Or to go a level deeper, if you have 2 occurrences of rename(2) from the stdlibc ...
rename('a', 'b'); rename('c', 'd');
...and the compiler decides on out of order execution or optimizing by scheduling on different cpus, you can get a and d existing at the same time.
The reason it won't happen in the example you posted is the shell ensures the atomicity (by not forking the second mv until the wait() on the first returns)
`inotifywait` actually sees them in order, but nothing ensure that it's that way.
$ inotifywait -m /tmp
/tmp/ MOVED_FROM a
/tmp/ MOVED_TO b
/tmp/ MOVED_FROM c
/tmp/ MOVED_TO d
$ stat b d | grep '^Change'
Change: 2026-02-06 12:22:55.394932841 +0100
Change: 2026-02-06 12:22:55.394932841 +0100
Given
$ (
set -eo pipefail
for i in {1..10000}
do
printf '%d ' "$i"
touch a c
mv a b &
mv c d &
wait
rm b d
done
)
1 2 3 4 5 6 .....
$ inotifywait -m -e MOVED_FROM,MOVED_TO /tmp > /tmp/output
cat /tmp/output | xargs -l4 | sort | uniq -c
9104 /tmp/ MOVED_FROM a /tmp/ MOVED_TO b /tmp/ MOVED_FROM c /tmp/ MOVED_TO d
896 /tmp/ MOVED_FROM c /tmp/ MOVED_TO d /tmp/ MOVED_FROM a /tmp/ MOVED_TO b