[RFC PATCH 03/11] NFS/NFSD: data structure enablement for nfs4_acl passthru support

[Mike Snitzer <snitzer@kernel.org>]

From: Mike Snitzer <snitzer@hammerspace.com>

Add setacl and getacl to export_operations structure. Both of these
methods allow NFSD to pass an nfs4_acl structure to exported
filesystem.

Update the nfs4_acl structure to allow for dual use of the new
nfs4_acl passthru support in addition to its existing usage. This
duality is reflected through use of a union, but the xdr_buf payload
is used to initialize all members in the union needed for passthru (in
a later NFSD commit).

Move nfs4_acl_type structure to include/linux/nfsacl.h so that it can
be used by NFS and NFSD.

Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
---
 include/linux/exportfs.h |  9 +++++++++
 include/linux/nfs4.h     | 23 +++++++++++++++++++++--
 include/linux/nfs_xdr.h  |  7 -------
 include/linux/nfsacl.h   |  7 +++++++
 4 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 0262c9258b34..e73e7ba5ef45 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -10,6 +10,7 @@ struct inode;
 struct iomap;
 struct super_block;
 struct vfsmount;
+struct nfs4_acl;
 
 /* limit the handle size to NFSv4 handle size now */
 #define MAX_HANDLE_SZ 128
@@ -215,6 +216,12 @@ struct fid {
  * commit_metadata:
  *    @commit_metadata should commit metadata changes to stable storage.
  *
+ * setacl:
+ *    @setacl will use the nfs4_acl @acl to establish the acl using SETATTR.
+ *
+ * getacl:
+ *    @getacl will use the nfs4_acl @acl to retrieve the acl using GETATTR.
+ *
  * Locking rules:
  *    get_parent is called with child->d_inode->i_mutex down
  *    get_name is not (which is possibly inconsistent)
@@ -238,6 +245,8 @@ struct export_operations {
 			  bool write, u32 *device_generation);
 	int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
 			     int nr_iomaps, struct iattr *iattr);
+	int (*setacl)(struct inode *inode, struct nfs4_acl *acl);
+	int (*getacl)(struct inode *inode, struct nfs4_acl *acl);
 #define	EXPORT_OP_NOWCC			(0x1) /* don't collect v3 wcc data */
 #define	EXPORT_OP_NOSUBTREECHK		(0x2) /* no subtree checking */
 #define	EXPORT_OP_CLOSE_BEFORE_UNLINK	(0x4) /* close files before unlink */
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 147a4d178c12..28c10edeea5b 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -16,6 +16,7 @@
 #include <linux/list.h>
 #include <linux/uidgid.h>
 #include <uapi/linux/nfs4.h>
+#include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/sunrpc/xdrgen/nfs4_1.h>
 
@@ -38,8 +39,26 @@ struct nfs4_ace {
 };
 
 struct nfs4_acl {
-	uint32_t	naces;
-	struct nfs4_ace	aces[];
+	union {
+		struct {
+			/*
+			 * Payload to use for deferred decode into
+			 * pages once ACL passthru is required
+			 * (which uses abnormal members below).
+			 */
+			struct xdr_buf payload;
+			/* Normal counted list of ACEs */
+			uint32_t naces;
+			struct nfs4_ace	aces[];
+		} __attribute__ ((packed));
+		struct {
+			/* Abnormal counted list of pages */
+			uint32_t type;
+			uint32_t len;
+			uint32_t pgbase;
+			struct page *pages[];
+		} __attribute__ ((packed));
+	};
 };
 
 #define NFS4_MAXLABELLEN	2048
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 2b30af613bab..65dbe7c05346 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -827,13 +827,6 @@ struct nfs_setattrargs {
 	const struct nfs4_label		*label;
 };
 
-enum nfs4_acl_type {
-	NFS4ACL_NONE = 0,
-	NFS4ACL_ACL,
-	NFS4ACL_DACL,
-	NFS4ACL_SACL,
-};
-
 struct nfs_setaclargs {
 	struct nfs4_sequence_args	seq_args;
 	struct nfs_fh *			fh;
diff --git a/include/linux/nfsacl.h b/include/linux/nfsacl.h
index 8e76a79cdc6a..a1941dc56db0 100644
--- a/include/linux/nfsacl.h
+++ b/include/linux/nfsacl.h
@@ -22,6 +22,13 @@
 #define NFS_ACL_MAX_ENTRIES_INLINE	(5)
 #define NFS_ACL_INLINE_BUFSIZE	((2*(2+3*NFS_ACL_MAX_ENTRIES_INLINE)) << 2)
 
+enum nfs4_acl_type {
+	NFS4ACL_NONE = 0,
+	NFS4ACL_ACL,
+	NFS4ACL_DACL,
+	NFS4ACL_SACL,
+};
+
 static inline unsigned int
 nfsacl_size(struct posix_acl *acl_access, struct posix_acl *acl_default)
 {
-- 
2.44.0