df does not look for filesystem that directory is on

[Gelbpunkt]

GNU coreutils will accept paths that are not mounts as parameters and output the filesystem they are from:

$ df /usr
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/nvme0n1p2 490150872 76337224 388841924  17% /

while uutils will only output something if the path given is the mountpoint

$ df /usr
df: no file systems processed

Sorry for the bad title, I wasn't really sure how to phrase this.

[Devel08]

I can't reproduce it:

$ cargo run --release df /usr
    Finished `release` profile [optimized] target(s) in 0.12s
     Running `target/release/coreutils df /usr`
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/nvme0n1p4  40049168 32611680   5380848  86% /

[hlsxx]

Same here, can't reproduce the bug, @Gelbpunkt which version of uutils did you use?

[JustSoup312]

This only seems to occur if df is run inside of a chroot.

Running df with a path results in the listed error, but running it without any subcommands or flags gives:

df: cannot read table of mounted file systems: No such file or directory

Are there some bind-mounts missing in the environment?

[Gelbpunkt]

Yeah, this is in a chroot:

# uutils
/ # df
Filesystem     1K-blocks     Used Available Use% Mounted on
tmpfs               1024        0      1024   0% /dev
tmpfs            7771240        0   7771240   0% /dev/shm
/dev/nvme0n1p2 490150872 76946628 388232520  17% /var/cache/apk
/dev/nvme0n1p2 490150872 76946628 388232520  17% /etc/apk/keys
/ # df /
df: no file systems processed
/ # df /usr
df: no file systems processed

# GNU coreutils
/ # df
Filesystem     1K-blocks     Used Available Use% Mounted on
tmpfs               1024        0      1024   0% /dev
tmpfs            7771240        0   7771240   0% /dev/shm
/dev/nvme0n1p2 490150872 76941052 388238096  17% /etc/apk/keys
/ # df /usr
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/nvme0n1p2 490150872 76941052 388238096  17% /mnt/pmbootstrap/packages
/ # df /
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/nvme0n1p2 490150872 76941076 388238072  17% /mnt/pmbootstrap/packages

Also interesting that GNU coreutils show one extra entry.