[PATCH] NFS: Add support for NFSv3 ACLs

 This adds acl support fo nfs clients via the NFSACL protocol extension, by
 implementing the getxattr, listxattr, setxattr, and removexattr iops for the
 system.posix_acl_access and system.posix_acl_default attributes.  This patch
 implements a dumb version that uses no caching (and thus adds some overhead).
 (Another patch in this patchset adds caching as well.)

 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
 Acked-by: Olaf Kirch <okir@suse.de>
 Signed-off-by: Andrew Morton <akpm@osdl.org>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 303 insertions, 0 deletions

diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
new file mode 100644
index 000000000000..393ba79fc14f
--- /dev/null
+++ b/fs/nfs/nfs3acl.c
@@ -0,0 +1,303 @@
+#include <linux/fs.h>
+#include <linux/nfs.h>
+#include <linux/nfs3.h>
+#include <linux/nfs_fs.h>
+#include <linux/xattr_acl.h>
+#include <linux/nfsacl.h>
+
+#define NFSDBG_FACILITY	NFSDBG_PROC
+
+ssize_t nfs3_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl;
+	int pos=0, len=0;
+
+#	define output(s) do {						\
+			if (pos + sizeof(s) <= size) {			\
+				memcpy(buffer + pos, s, sizeof(s));	\
+				pos += sizeof(s);			\
+			}						\
+			len += sizeof(s);				\
+		} while(0)
+
+	acl = nfs3_proc_getacl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl) {
+		output("system.posix_acl_access");
+		posix_acl_release(acl);
+	}
+
+	if (S_ISDIR(inode->i_mode)) {
+		acl = nfs3_proc_getacl(inode, ACL_TYPE_DEFAULT);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (acl) {
+			output("system.posix_acl_default");
+			posix_acl_release(acl);
+		}
+	}
+
+#	undef output
+
+	if (!buffer || len <= size)
+		return len;
+	return -ERANGE;
+}
+
+ssize_t nfs3_getxattr(struct dentry *dentry, const char *name,
+		void *buffer, size_t size)
+{
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl;
+	int type, error = 0;
+
+	if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+		type = ACL_TYPE_ACCESS;
+	else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+		type = ACL_TYPE_DEFAULT;
+	else
+		return -EOPNOTSUPP;
+
+	acl = nfs3_proc_getacl(inode, type);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	else if (acl) {
+		if (type == ACL_TYPE_ACCESS && acl->a_count == 0)
+			error = -ENODATA;
+		else
+			error = posix_acl_to_xattr(acl, buffer, size);
+		posix_acl_release(acl);
+	} else
+		error = -ENODATA;
+
+	return error;
+}
+
+int nfs3_setxattr(struct dentry *dentry, const char *name,
+	     const void *value, size_t size, int flags)
+{
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl;
+	int type, error;
+
+	if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+		type = ACL_TYPE_ACCESS;
+	else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+		type = ACL_TYPE_DEFAULT;
+	else
+		return -EOPNOTSUPP;
+
+	acl = posix_acl_from_xattr(value, size);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	error = nfs3_proc_setacl(inode, type, acl);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+int nfs3_removexattr(struct dentry *dentry, const char *name)
+{
+	struct inode *inode = dentry->d_inode;
+	int type;
+
+	if (strcmp(name, XATTR_NAME_ACL_ACCESS) == 0)
+		type = ACL_TYPE_ACCESS;
+	else if (strcmp(name, XATTR_NAME_ACL_DEFAULT) == 0)
+		type = ACL_TYPE_DEFAULT;
+	else
+		return -EOPNOTSUPP;
+
+	return nfs3_proc_setacl(inode, type, NULL);
+}
+
+struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+	struct nfs_fattr fattr;
+	struct page *pages[NFSACL_MAXPAGES] = { };
+	struct nfs3_getaclargs args = {
+		.fh = NFS_FH(inode),
+		/* The xdr layer may allocate pages here. */
+		.pages = pages,
+	};
+	struct nfs3_getaclres res = {
+		.fattr =	&fattr,
+	};
+	struct posix_acl *acl = NULL;
+	int status, count;
+
+	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	switch (type) {
+		case ACL_TYPE_ACCESS:
+			args.mask = NFS_ACLCNT|NFS_ACL;
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			if (!S_ISDIR(inode->i_mode))
+				return NULL;
+			args.mask = NFS_DFACLCNT|NFS_DFACL;
+			break;
+
+		default:
+			return ERR_PTR(-EINVAL);
+	}
+
+	dprintk("NFS call getacl\n");
+	status = rpc_call(server->client_acl, ACLPROC3_GETACL,
+			  &args, &res, 0);
+	dprintk("NFS reply getacl: %d\n", status);
+
+	/* pages may have been allocated at the xdr layer. */
+	for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
+		__free_page(args.pages[count]);
+
+	switch (status) {
+		case 0:
+			status = nfs_refresh_inode(inode, &fattr);
+			break;
+		case -EPFNOSUPPORT:
+		case -EPROTONOSUPPORT:
+			dprintk("NFS_V3_ACL extension not supported; disabling\n");
+			server->caps &= ~NFS_CAP_ACLS;
+		case -ENOTSUPP:
+			status = -EOPNOTSUPP;
+		default:
+			goto getout;
+	}
+	if ((args.mask & res.mask) != args.mask) {
+		status = -EIO;
+		goto getout;
+	}
+
+	if (res.acl_access != NULL) {
+		if (posix_acl_equiv_mode(res.acl_access, NULL) == 0) {
+			posix_acl_release(res.acl_access);
+			res.acl_access = NULL;
+		}
+	}
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			acl = res.acl_access;
+			res.acl_access = NULL;
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			acl = res.acl_default;
+			res.acl_default = NULL;
+	}
+
+getout:
+	posix_acl_release(res.acl_access);
+	posix_acl_release(res.acl_default);
+
+	if (status != 0) {
+		posix_acl_release(acl);
+		acl = ERR_PTR(status);
+	}
+	return acl;
+}
+
+static int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
+		  struct posix_acl *dfacl)
+{
+	struct nfs_server *server = NFS_SERVER(inode);
+	struct nfs_fattr fattr;
+	struct page *pages[NFSACL_MAXPAGES] = { };
+	struct nfs3_setaclargs args = {
+		.inode = inode,
+		.mask = NFS_ACL,
+		.acl_access = acl,
+		.pages = pages,
+	};
+	int status, count;
+
+	status = -EOPNOTSUPP;
+	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
+		goto out;
+
+	/* We are doing this here, because XDR marshalling can only
+	   return -ENOMEM. */
+	status = -ENOSPC;
+	if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
+		goto out;
+	if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
+		goto out;
+	if (S_ISDIR(inode->i_mode)) {
+		args.mask |= NFS_DFACL;
+		args.acl_default = dfacl;
+	}
+
+	dprintk("NFS call setacl\n");
+	nfs_begin_data_update(inode);
+	status = rpc_call(server->client_acl, ACLPROC3_SETACL,
+			  &args, &fattr, 0);
+	NFS_FLAGS(inode) |= NFS_INO_INVALID_ACCESS;
+	nfs_end_data_update(inode);
+	dprintk("NFS reply setacl: %d\n", status);
+
+	/* pages may have been allocated at the xdr layer. */
+	for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
+		__free_page(args.pages[count]);
+
+	switch (status) {
+		case 0:
+			status = nfs_refresh_inode(inode, &fattr);
+			break;
+		case -EPFNOSUPPORT:
+		case -EPROTONOSUPPORT:
+			dprintk("NFS_V3_ACL SETACL RPC not supported"
+					"(will not retry)\n");
+			server->caps &= ~NFS_CAP_ACLS;
+		case -ENOTSUPP:
+			status = -EOPNOTSUPP;
+	}
+out:
+	return status;
+}
+
+int nfs3_proc_setacl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	struct posix_acl *alloc = NULL, *dfacl = NULL;
+	int status;
+
+	if (S_ISDIR(inode->i_mode)) {
+		switch(type) {
+			case ACL_TYPE_ACCESS:
+				alloc = dfacl = nfs3_proc_getacl(inode,
+						ACL_TYPE_DEFAULT);
+				if (IS_ERR(alloc))
+					goto fail;
+				break;
+
+			case ACL_TYPE_DEFAULT:
+				dfacl = acl;
+				alloc = acl = nfs3_proc_getacl(inode,
+						ACL_TYPE_ACCESS);
+				if (IS_ERR(alloc))
+					goto fail;
+				break;
+
+			default:
+				return -EINVAL;
+		}
+	} else if (type != ACL_TYPE_ACCESS)
+			return -EINVAL;
+
+	if (acl == NULL) {
+		alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
+		if (IS_ERR(alloc))
+			goto fail;
+	}
+	status = nfs3_proc_setacls(inode, acl, dfacl);
+	posix_acl_release(alloc);
+	return status;
+
+fail:
+	return PTR_ERR(alloc);
+}