[1.2] rootfs: improve mount-related errors #4740
Merged
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This is a backport of #4734 to 1.2.x.
While debugging an issue involving failing mounts, I discovered that
just returning the plain mount error message when we are in the fallback
code for handling locked mounts leads to unnecessary confusion.
It also doesn't help that podman currently forcefully sets "rw" on
mounts, which means that rootless containers are likely to hit the
locked mounts issue fairly often.
So we should improve our error messages to explain why the mount is
failing in the locked flags case.
Also, when reading mount errors, it is quite hard to make sense of mount
flags in their hex form. As this is the error path, the minor performance
impact of constructing a string is probably not worth hyper-optimising.
(Though maybe @kolyshkin has an opinion on this.)
Signed-off-by: Aleksa Sarai [email protected]