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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Jeff Layton <jlayton@kernel.org>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] nfsd: clean up mounted_on_fileid handling
Thread-Topic: [PATCH] nfsd: clean up mounted_on_fileid handling
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Date:   Thu, 8 Sep 2022 19:19:10 +0000
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> On Sep 8, 2022, at 12:31 PM, Jeff Layton <jlayton@kernel.org> wrote:
>=20
> We only need the inode number for this, not a full rack of attributes.
> Rename this function make it take a pointer to a u64 instead of
> struct kstat, and change it to just request STATX_INO.
>=20
> Signed-off-by: Jeff Layton <jlayton@kernel.org>

I'm relying on your expertise in this area.

As I apply this for testing, may I rename get_mounted_on_ino() to
nfsd4_get_mounted_on_ino() ?


> ---
> fs/nfsd/nfs4xdr.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>=20
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 1e9690a061ec..5980df859c3a 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2774,9 +2774,10 @@ static __be32 fattr_handle_absent_fs(u32 *bmval0, =
u32 *bmval1, u32 *bmval2, u32
> }
>=20
>=20
> -static int get_parent_attributes(struct svc_export *exp, struct kstat *s=
tat)
> +static int get_mounted_on_ino(struct svc_export *exp, u64 *pino)
> {
> 	struct path path =3D exp->ex_path;
> +	struct kstat stat;
> 	int err;
>=20
> 	path_get(&path);
> @@ -2784,8 +2785,10 @@ static int get_parent_attributes(struct svc_export=
 *exp, struct kstat *stat)
> 		if (path.dentry !=3D path.mnt->mnt_root)
> 			break;
> 	}
> -	err =3D vfs_getattr(&path, stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_ST=
AT);
> +	err =3D vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT);
> 	path_put(&path);
> +	if (!err)
> +		*pino =3D stat.ino;
> 	return err;
> }
>=20
> @@ -3282,22 +3285,21 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct=
 svc_fh *fhp,
> 		*p++ =3D cpu_to_be32(stat.btime.tv_nsec);
> 	}
> 	if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
> -		struct kstat parent_stat;
> 		u64 ino =3D stat.ino;
>=20
> 		p =3D xdr_reserve_space(xdr, 8);
> 		if (!p)
>                 	goto out_resource;
> 		/*
> -		 * Get parent's attributes if not ignoring crossmount
> -		 * and this is the root of a cross-mounted filesystem.
> +		 * Get ino of mountpoint in parent filesystem, if not ignoring
> +		 * crossmount and this is the root of a cross-mounted
> +		 * filesystem.
> 		 */
> 		if (ignore_crossmnt =3D=3D 0 &&
> 		    dentry =3D=3D exp->ex_path.mnt->mnt_root) {
> -			err =3D get_parent_attributes(exp, &parent_stat);
> +			err =3D get_mounted_on_ino(exp, &ino);
> 			if (err)
> 				goto out_nfserr;
> -			ino =3D parent_stat.ino;
> 		}
> 		p =3D xdr_encode_hyper(p, ino);
> 	}
> --=20
> 2.37.3
>=20

--
Chuck Lever