[RFC v6 40/40] nfs: Add support for the v4.1 dacl attribute

[Andreas Gruenbacher <andreas.gruenbacher@gmail.com>]

The dacl attribute includes Automatic Inheritance flags not supported by
the acl attribute.  it is only supported in NFS version 4.1 and higher.
On systems where NFS version 4.0 is still the default, an additional
mount option is needed:

    mount -t nfs4 -o vers=4.1 [...]

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/nfs/nfs4proc.c       |  2 +-
 fs/nfs/nfs4xdr.c        | 55 ++++++++++++++++++++++++++++++++++++++++++-------
 include/linux/nfs_xdr.h |  2 +-
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e72f53e..5b53e90 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4482,7 +4482,7 @@ static struct richacl *__nfs4_get_acl_uncached(struct inode *inode)
 	struct nfs_server *server = NFS_SERVER(inode);
 	struct page *pages[DIV_ROUND_UP(NFS4ACL_SIZE_MAX, PAGE_SIZE)] = {};
 	struct nfs_getaclargs args = {
-		.fh = NFS_FH(inode),
+		.inode = inode,
 		.acl_pages = pages,
 		.acl_len = ARRAY_SIZE(pages) * PAGE_SIZE,
 	};
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 78a9fbd..bfb4d49 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1648,9 +1648,16 @@ encode_setacl(struct xdr_stream *xdr, struct nfs_setaclargs *arg, struct compoun
 	encode_nfs4_stateid(xdr, &zero_stateid);
 
 	/* Encode attribute bitmap. */
-	p = reserve_space(xdr, 2*4);
-	*p++ = cpu_to_be32(1);
-	*p = cpu_to_be32(FATTR4_WORD0_ACL);
+	if (arg->server->attr_bitmask[1] & FATTR4_WORD1_DACL) {
+		p = reserve_space(xdr, 3*4);
+		*p++ = cpu_to_be32(2);
+		*p++ = 0;
+		*p = cpu_to_be32(FATTR4_WORD1_DACL);
+	} else {
+		p = reserve_space(xdr, 2*4);
+		*p++ = cpu_to_be32(1);
+		*p = cpu_to_be32(FATTR4_WORD0_ACL);
+	}
 
 	attrlen_offset = xdr->buf->len;
 	xdr_reserve_space(xdr, 4);  /* to be backfilled later */
@@ -2485,9 +2492,12 @@ static void nfs4_xdr_enc_getacl(struct rpc_rqst *req, struct xdr_stream *xdr,
 
 	encode_compound_hdr(xdr, req, &hdr);
 	encode_sequence(xdr, &args->seq_args, &hdr);
-	encode_putfh(xdr, args->fh, &hdr);
+	encode_putfh(xdr, NFS_FH(args->inode), &hdr);
 	replen = hdr.replen + op_decode_hdr_maxsz + 1;
-	encode_getattr_two(xdr, FATTR4_WORD0_ACL, FATTR4_WORD1_MODE, &hdr);
+	if (NFS_SERVER(args->inode)->attr_bitmask[1] & FATTR4_WORD1_DACL)
+		encode_getattr_two(xdr, 0, FATTR4_WORD1_MODE | FATTR4_WORD1_DACL, &hdr);
+	else
+		encode_getattr_two(xdr, FATTR4_WORD0_ACL, FATTR4_WORD1_MODE, &hdr);
 
 	xdr_inline_pages(&req->rq_rcv_buf, replen << 2,
 		args->acl_pages, 0, args->acl_len);
@@ -5375,14 +5385,28 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
 
 	if (unlikely(bitmap[0] & (FATTR4_WORD0_ACL - 1U)))
 		return -EIO;
-	if (likely(bitmap[0] & FATTR4_WORD0_ACL)) {
+
+	if (bitmap[0] & FATTR4_WORD0_ACL) {
+		struct richace *ace;
+
+		if (bitmap[1] & FATTR4_WORD1_DACL)
+			return -EIO;
+
 		acl = decode_acl_entries(xdr, res->server);
 		status = PTR_ERR(acl);
 		if (IS_ERR(acl))
 			goto out;
+
+		status = -EIO;
+		richacl_for_each_entry(ace, acl) {
+			if (ace->e_flags & RICHACE_INHERITED_ACE)
+				goto out;
+		}
 		bitmap[0] &= ~FATTR4_WORD0_ACL;
-	} else
+	} else if (!(bitmap[1] & FATTR4_WORD1_DACL)) {
 		status = -EOPNOTSUPP;
+		goto out;
+	}
 
 	status = -EIO;
 	if (unlikely(bitmap[0]))
@@ -5391,6 +5415,23 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
 	status = decode_attr_mode(xdr, bitmap, &res->mode);
 	if (status < 0)
 		goto out;
+	if (bitmap[1] & FATTR4_WORD1_DACL) {
+		unsigned int flags;
+		__be32 *p;
+
+		p = xdr_inline_decode(xdr, 4);
+		status = -EIO;
+		if (unlikely(!p))
+			goto out;
+		flags = be32_to_cpup(p);
+
+		acl = decode_acl_entries(xdr, res->server);
+		status = PTR_ERR(acl);
+		if (IS_ERR(acl))
+			goto out;
+		acl->a_flags = flags;
+		bitmap[1] &= ~FATTR4_WORD1_DACL;
+	}
 	status = 0;
 
 out:
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index f1c8f93..abe0b66 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -695,7 +695,7 @@ struct nfs_setaclres {
 
 struct nfs_getaclargs {
 	struct nfs4_sequence_args 	seq_args;
-	struct nfs_fh *			fh;
+	struct inode *			inode;
 	size_t				acl_len;
 	struct page **			acl_pages;
 };
-- 
2.5.0