Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/nfs_common/nfsacl.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/nfsacl.h | 3 ++
2 files changed, 74 insertions(+)
diff --git a/fs/nfs_common/nfsacl.c b/fs/nfs_common/nfsacl.c
index 79c563c1a5e8..5a5bd85d08f8 100644
--- a/fs/nfs_common/nfsacl.c
+++ b/fs/nfs_common/nfsacl.c
@@ -136,6 +136,77 @@ int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
}
EXPORT_SYMBOL_GPL(nfsacl_encode);
+/**
+ * nfs_stream_encode_acl - Encode an NFSv3 ACL
+ *
+ * @xdr: an xdr_stream positioned to receive an encoded ACL
+ * @inode: inode of file whose ACL this is
+ * @acl: posix_acl to encode
+ * @encode_entries: whether to encode ACEs as well
+ * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
+ *
+ * Return values:
+ * %false: The ACL could not be encoded
+ * %true: @xdr is advanced to the next available position
+ */
+bool nfs_stream_encode_acl(struct xdr_stream *xdr, struct inode *inode,
+ struct posix_acl *acl, int encode_entries,
+ int typeflag)
+{
+ const size_t elem_size = XDR_UNIT * 3;
+ u32 entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
+ struct nfsacl_encode_desc nfsacl_desc = {
+ .desc = {
+ .elem_size = elem_size,
+ .array_len = encode_entries ? entries : 0,
+ .xcode = xdr_nfsace_encode,
+ },
+ .acl = acl,
+ .typeflag = typeflag,
+ .uid = inode->i_uid,
+ .gid = inode->i_gid,
+ };
+ struct nfsacl_simple_acl aclbuf;
+ unsigned int base;
+ int err;
+
+ if (entries > NFS_ACL_MAX_ENTRIES)
+ return false;
+ if (xdr_stream_encode_u32(xdr, entries) < 0)
+ return false;
+
+ if (encode_entries && acl && acl->a_count == 3) {
+ struct posix_acl *acl2 = &aclbuf.acl;
+
+ /* Avoid the use of posix_acl_alloc(). nfsacl_encode() is
+ * invoked in contexts where a memory allocation failure is
+ * fatal. Fortunately this fake ACL is small enough to
+ * construct on the stack. */
+ posix_acl_init(acl2, 4);
+
+ /* Insert entries in canonical order: other orders seem
+ to confuse Solaris VxFS. */
+ acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */
+ acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */
+ acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */
+ acl2->a_entries[2].e_tag = ACL_MASK;
+ acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */
+ nfsacl_desc.acl = acl2;
+ }
+
+ base = xdr_stream_pos(xdr);
+ if (!xdr_reserve_space(xdr, XDR_UNIT +
+ elem_size * nfsacl_desc.desc.array_len))
+ return false;
+ err = xdr_encode_array2(xdr->buf, base, &nfsacl_desc.desc);
+ if (err)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(nfs_stream_encode_acl);
+
+
struct nfsacl_decode_desc {
struct xdr_array2_desc desc;
unsigned int count;
diff --git a/include/linux/nfsacl.h b/include/linux/nfsacl.h
index 0ba99c513649..8e76a79cdc6a 100644
--- a/include/linux/nfsacl.h
+++ b/include/linux/nfsacl.h
@@ -41,5 +41,8 @@ nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
extern bool
nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
struct posix_acl **pacl);
+extern bool
+nfs_stream_encode_acl(struct xdr_stream *xdr, struct inode *inode,
+ struct posix_acl *acl, int encode_entries, int typeflag);
#endif /* __LINUX_NFSACL_H */
