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Re: [PATCH 5/5] 9pfs: fix removing non-existent POSIX ACL xattr on macOS
From: |
Christian Schoenebeck |
Subject: |
Re: [PATCH 5/5] 9pfs: fix removing non-existent POSIX ACL xattr on macOS host |
Date: |
Thu, 21 Apr 2022 12:55:24 +0200 |
On Donnerstag, 21. April 2022 10:26:11 CEST Greg Kurz wrote:
> On Tue, 19 Apr 2022 13:43:30 +0200
>
> Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:
> > When mapped POSIX ACL is used, we are ignoring errors when trying
> > to remove a POSIX ACL xattr that does not exist. On Linux hosts we
> > would get ENODATA in such cases, on macOS hosts however we get
> > ENOATTR instead, so ignore ENOATTR errors as well.
> >
> > This patch fixes e.g. a command on Linux guest like:
> > cp --preserve=mode old new
> >
> > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> > ---
> >
> > hw/9pfs/9p-posix-acl.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
> > index eadae270dd..2bf155f941 100644
> > --- a/hw/9pfs/9p-posix-acl.c
> > +++ b/hw/9pfs/9p-posix-acl.c
> > @@ -65,7 +65,13 @@ static int mp_pacl_removexattr(FsContext *ctx,
> >
> > int ret;
> >
> > ret = local_removexattr_nofollow(ctx, path, MAP_ACL_ACCESS);
> >
> > - if (ret == -1 && errno == ENODATA) {
> > + if (ret == -1 &&
> > + (errno == ENODATA
> > +#ifdef ENOATTR
> > + || errno == ENOATTR
> > +#endif
> > + )
>
> We already have this in <qemu/xattr.h> which is included by
> 9p-posix-acl.c :
>
> /*
> * Modern distributions (e.g. Fedora 15), have no libattr.so, place attr.h
> * in /usr/include/sys, and don't have ENOATTR.
> */
>
>
> #ifdef CONFIG_LIBATTR
> # include <attr/xattr.h>
> #else
> # if !defined(ENOATTR)
> # define ENOATTR ENODATA
> # endif
> # include <sys/xattr.h>
> #endif
>
> I guess this patch could just s/ENODATA/ENOATTR/ to avoid the
> extra ifdefery.
Not viable, because macOS does have both ENODATA==96 and ENOATTR==93. On Linux
the two macros were historically defined to the same numeric values, that's
why it worked there.
Maybe I should define a separate macro like:
#if ...
# define P9_ENOATTR ENOATTR
#else
# define P9_ENOATTR ENODATA
#end
?
Actually good that you pointed me at this, because I just realized there is a
2nd place in 9p-posix-acl.c which would require this as well. For some reason
the 2nd place just did not trigger while I was testing it on macOS.
Best regards,
Christian Schoenebeck
- Re: [PATCH 3/5] 9pfs: fix wrong encoding of rdev field in Rgetattr on macOS, (continued)
[PATCH 4/5] 9pfs: fix wrong errno being sent to Linux client on macOS host, Christian Schoenebeck, 2022/04/19
[PATCH 5/5] 9pfs: fix removing non-existent POSIX ACL xattr on macOS host, Christian Schoenebeck, 2022/04/19