On 10/8/22 17:26, Florian Weimer wrote:
* David Howells:
We're seeing issues in autofs and xfstests whereby linux/mount.h (the UAPI
version) as included indirectly by linux/fs.h is conflicting with
sys/mount.h (there's a struct and an enum).
Would it be possible to just remove the #include from linux/fs.h (as patch
below) and rely on those hopefully few things that need mount flags that don't
use the glibc header for them working around it by configuration?
Wasn't <linux/mount.h> split from <linux/fs.h> relatively recently, and
userspace is probably using <linux/fs.h> to get the mount flag
definitions?
Not sure myself but this is in the user space kernel includes
and sys/mount.h has pretty much what linux/mount.h has plus a
few function declarations. It's almost a complete duplication.
The reality is that the enum declaration could be changed to
#defines (not a preferred approach) which leaves only the
struct mount_attr which is the difficult one to resolve.
In retrospect, it would have been better to add the new fsmount stuff to
a separate header file, so that we could include that easily from
<sys/mount.h> on the glibc side. Adhemerval posted a glibc patch to
fake that (for recent compilers):
[PATCH] linux: Fix sys/mount.h usage with kernel headers
<https://sourceware.org/pipermail/libc-alpha/2022-August/141316.html>
I think it should work reliably, so that's probably the direction we are
going to move in.
Looked a lot more complicated than I thought it could be, enough
that I can't say if it will work so I'll take your word for it.
Ian
