Message-ID: <158454420278.2864823.13636081072762779412.stgit@warthog.procyon.org.uk>
Date:   Wed, 18 Mar 2020 15:10:02 +0000
From:   David Howells <dhowells@...hat.com>
To:     torvalds@...ux-foundation.org, viro@...iv.linux.org.uk
Cc:     Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        linux-nfs@...r.kernel.org, dhowells@...hat.com, raven@...maw.net,
        mszeredi@...hat.com, christian@...uner.io, jannh@...gle.com,
        darrick.wong@...cle.com, kzak@...hat.com, jlayton@...hat.com,
        linux-api@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 13/13] fsinfo: Example support for NFS [ver #19]

Add the ability to list NFS server addresses and hostname, timestamp
information and capabilities as an example.

Is this useful for export from NFS?  Is there anything else that would be
useful?

Signed-off-by: David Howells <dhowells@...hat.com>
cc: Trond Myklebust <trond.myklebust@...merspace.com>
cc: Anna Schumaker <anna.schumaker@...app.com>
cc: linux-nfs@...r.kernel.org
---

 fs/nfs/Makefile              |    1 
 fs/nfs/fsinfo.c              |  230 ++++++++++++++++++++++++++++++++++++++++++
 fs/nfs/internal.h            |    6 +
 fs/nfs/nfs4super.c           |    3 +
 fs/nfs/super.c               |    3 +
 include/uapi/linux/fsinfo.h  |   29 +++++
 include/uapi/linux/windows.h |   35 ++++++
 samples/vfs/test-fsinfo.c    |   38 +++++++
 8 files changed, 345 insertions(+)
 create mode 100644 fs/nfs/fsinfo.c
 create mode 100644 include/uapi/linux/windows.h

diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index 2433c3e03cfa..20fbc9596833 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -13,6 +13,7 @@ nfs-y 			:= client.o dir.o file.o getroot.o inode.o super.o \
 nfs-$(CONFIG_ROOT_NFS)	+= nfsroot.o
 nfs-$(CONFIG_SYSCTL)	+= sysctl.o
 nfs-$(CONFIG_NFS_FSCACHE) += fscache.o fscache-index.o
+nfs-$(CONFIG_FSINFO)	+= fsinfo.o
 
 obj-$(CONFIG_NFS_V2) += nfsv2.o
 nfsv2-y := nfs2super.o proc.o nfs2xdr.o
diff --git a/fs/nfs/fsinfo.c b/fs/nfs/fsinfo.c
new file mode 100644
index 000000000000..a0299ec27efd
--- /dev/null
+++ b/fs/nfs/fsinfo.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Filesystem information for NFS
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@...hat.com)
+ */
+
+#include <linux/nfs_fs.h>
+#include <linux/windows.h>
+#include "internal.h"
+
+static const struct fsinfo_timestamp_info nfs_timestamp_info = {
+	.atime = {
+		.minimum	= 0,
+		.maximum	= UINT_MAX,
+		.gran_mantissa	= 1,
+		.gran_exponent	= 0,
+	},
+	.mtime = {
+		.minimum	= 0,
+		.maximum	= UINT_MAX,
+		.gran_mantissa	= 1,
+		.gran_exponent	= 0,
+	},
+	.ctime = {
+		.minimum	= 0,
+		.maximum	= UINT_MAX,
+		.gran_mantissa	= 1,
+		.gran_exponent	= 0,
+	},
+	.btime = {
+		.minimum	= 0,
+		.maximum	= UINT_MAX,
+		.gran_mantissa	= 1,
+		.gran_exponent	= 0,
+	},
+};
+
+static int nfs_fsinfo_get_timestamp_info(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	struct fsinfo_timestamp_info *r = ctx->buffer;
+	unsigned long long nsec;
+	unsigned int rem, mant;
+	int exp = -9;
+
+	*r = nfs_timestamp_info;
+
+	nsec = server->time_delta.tv_nsec;
+	nsec += server->time_delta.tv_sec * 1000000000ULL;
+	if (nsec == 0)
+		goto out;
+
+	do {
+		mant = nsec;
+		rem = do_div(nsec, 10);
+		if (rem)
+			break;
+		exp++;
+	} while (nsec);
+
+	r->atime.gran_mantissa = mant;
+	r->atime.gran_exponent = exp;
+	r->btime.gran_mantissa = mant;
+	r->btime.gran_exponent = exp;
+	r->ctime.gran_mantissa = mant;
+	r->ctime.gran_exponent = exp;
+	r->mtime.gran_mantissa = mant;
+	r->mtime.gran_exponent = exp;
+
+out:
+	return sizeof(*r);
+}
+
+static int nfs_fsinfo_get_info(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	const struct nfs_client *clp = server->nfs_client;
+	struct fsinfo_nfs_info *r = ctx->buffer;
+
+	r->version		= clp->rpc_ops->version;
+	r->minor_version	= clp->cl_minorversion;
+	r->transport_proto	= clp->cl_proto;
+	return sizeof(*r);
+}
+
+static int nfs_fsinfo_get_server_name(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	const struct nfs_client *clp = server->nfs_client;
+
+	return fsinfo_string(clp->cl_hostname, ctx);
+}
+
+static int nfs_fsinfo_get_server_addresses(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	const struct nfs_client *clp = server->nfs_client;
+	struct fsinfo_nfs_server_address *addr = ctx->buffer;
+	int ret;
+
+	ret = 1 * sizeof(*addr);
+	if (ret <= ctx->buf_size)
+		memcpy(&addr[0].address, &clp->cl_addr, clp->cl_addrlen);
+	return ret;
+
+}
+
+static int nfs_fsinfo_get_gssapi_name(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	const struct nfs_client *clp = server->nfs_client;
+
+	return fsinfo_string(clp->cl_acceptor, ctx);
+}
+
+static int nfs_fsinfo_get_limits(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	struct fsinfo_limits *lim = ctx->buffer;
+
+	lim->max_file_size.hi	= 0;
+	lim->max_file_size.lo	= server->maxfilesize;
+	lim->max_ino.hi		= 0;
+	lim->max_ino.lo		= U64_MAX;
+	lim->max_hard_links	= UINT_MAX;
+	lim->max_uid		= UINT_MAX;
+	lim->max_gid		= UINT_MAX;
+	lim->max_filename_len	= NAME_MAX - 1;
+	lim->max_symlink_len	= PATH_MAX - 1;
+	return sizeof(*lim);
+}
+
+static int nfs_fsinfo_get_supports(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	struct fsinfo_supports *sup = ctx->buffer;
+
+	/* Don't set STATX_INO as i_ino is fabricated and may not be unique. */
+
+	if (!(server->caps & NFS_CAP_MODE))
+		sup->stx_mask |= STATX_TYPE | STATX_MODE;
+	if (server->caps & NFS_CAP_OWNER)
+		sup->stx_mask |= STATX_UID;
+	if (server->caps & NFS_CAP_OWNER_GROUP)
+		sup->stx_mask |= STATX_GID;
+	if (server->caps & NFS_CAP_ATIME)
+		sup->stx_mask |= STATX_ATIME;
+	if (server->caps & NFS_CAP_CTIME)
+		sup->stx_mask |= STATX_CTIME;
+	if (server->caps & NFS_CAP_MTIME)
+		sup->stx_mask |= STATX_MTIME;
+	if (server->attr_bitmask[0] & FATTR4_WORD0_SIZE)
+		sup->stx_mask |= STATX_SIZE;
+	if (server->attr_bitmask[1] & FATTR4_WORD1_NUMLINKS)
+		sup->stx_mask |= STATX_NLINK;
+
+	if (server->attr_bitmask[0] & FATTR4_WORD0_ARCHIVE)
+		sup->win_file_attrs |= ATTR_ARCHIVE;
+	if (server->attr_bitmask[0] & FATTR4_WORD0_HIDDEN)
+		sup->win_file_attrs |= ATTR_HIDDEN;
+	if (server->attr_bitmask[1] & FATTR4_WORD1_SYSTEM)
+		sup->win_file_attrs |= ATTR_SYSTEM;
+
+	sup->stx_attributes = STATX_ATTR_AUTOMOUNT;
+	return sizeof(*sup);
+}
+
+static int nfs_fsinfo_get_features(struct path *path, struct fsinfo_context *ctx)
+{
+	const struct nfs_server *server = NFS_SB(path->dentry->d_sb);
+	struct fsinfo_features *ft = ctx->buffer;
+
+	fsinfo_set_feature(ft, FSINFO_FEAT_IS_NETWORK_FS);
+	fsinfo_set_feature(ft, FSINFO_FEAT_AUTOMOUNTS);
+	fsinfo_set_feature(ft, FSINFO_FEAT_O_SYNC);
+	fsinfo_set_feature(ft, FSINFO_FEAT_O_DIRECT);
+	fsinfo_set_feature(ft, FSINFO_FEAT_ADV_LOCKS);
+	fsinfo_set_feature(ft, FSINFO_FEAT_DEVICE_FILES);
+	fsinfo_set_feature(ft, FSINFO_FEAT_UNIX_SPECIALS);
+	if (server->nfs_client->rpc_ops->version == 4) {
+		fsinfo_set_feature(ft, FSINFO_FEAT_LEASES);
+		fsinfo_set_feature(ft, FSINFO_FEAT_IVER_ALL_CHANGE);
+	}
+
+	if (server->caps & NFS_CAP_OWNER)
+		fsinfo_set_feature(ft, FSINFO_FEAT_UIDS);
+	if (server->caps & NFS_CAP_OWNER_GROUP)
+		fsinfo_set_feature(ft, FSINFO_FEAT_GIDS);
+	if (!(server->caps & NFS_CAP_MODE))
+		fsinfo_set_feature(ft, FSINFO_FEAT_NO_UNIX_MODE);
+	if (server->caps & NFS_CAP_ACLS)
+		fsinfo_set_feature(ft, FSINFO_FEAT_HAS_ACL);
+	if (server->caps & NFS_CAP_SYMLINKS)
+		fsinfo_set_feature(ft, FSINFO_FEAT_SYMLINKS);
+	if (server->caps & NFS_CAP_HARDLINKS)
+		fsinfo_set_feature(ft, FSINFO_FEAT_HARD_LINKS);
+	if (server->caps & NFS_CAP_ATIME)
+		fsinfo_set_feature(ft, FSINFO_FEAT_HAS_ATIME);
+	if (server->caps & NFS_CAP_CTIME)
+		fsinfo_set_feature(ft, FSINFO_FEAT_HAS_CTIME);
+	if (server->caps & NFS_CAP_MTIME)
+		fsinfo_set_feature(ft, FSINFO_FEAT_HAS_MTIME);
+
+	if (server->attr_bitmask[0] & FATTR4_WORD0_CASE_INSENSITIVE)
+		fsinfo_set_feature(ft, FSINFO_FEAT_NAME_CASE_INDEP);
+	if ((server->attr_bitmask[0] & FATTR4_WORD0_ARCHIVE) ||
+	    (server->attr_bitmask[0] & FATTR4_WORD0_HIDDEN) ||
+	    (server->attr_bitmask[1] & FATTR4_WORD1_SYSTEM))
+		fsinfo_set_feature(ft, FSINFO_FEAT_WINDOWS_ATTRS);
+
+	return sizeof(*ft);
+}
+
+static const struct fsinfo_attribute nfs_fsinfo_attributes[] = {
+	FSINFO_VSTRUCT	(FSINFO_ATTR_TIMESTAMP_INFO,	nfs_fsinfo_get_timestamp_info),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_LIMITS,		nfs_fsinfo_get_limits),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_SUPPORTS,		nfs_fsinfo_get_supports),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_FEATURES,		nfs_fsinfo_get_features),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_NFS_INFO,		nfs_fsinfo_get_info),
+	FSINFO_STRING	(FSINFO_ATTR_NFS_SERVER_NAME,	nfs_fsinfo_get_server_name),
+	FSINFO_LIST	(FSINFO_ATTR_NFS_SERVER_ADDRESSES, nfs_fsinfo_get_server_addresses),
+	FSINFO_STRING	(FSINFO_ATTR_NFS_GSSAPI_NAME,	nfs_fsinfo_get_gssapi_name),
+	{}
+};
+
+int nfs_fsinfo(struct path *path, struct fsinfo_context *ctx)
+{
+	return fsinfo_get_attribute(path, ctx, nfs_fsinfo_attributes);
+}
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index f80c47d5ff27..59e407066b45 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -10,6 +10,7 @@
 #include <linux/sunrpc/addr.h>
 #include <linux/nfs_page.h>
 #include <linux/wait_bit.h>
+#include <linux/fsinfo.h>
 
 #define NFS_SB_MASK (SB_RDONLY|SB_NOSUID|SB_NODEV|SB_NOEXEC|SB_SYNCHRONOUS)
 
@@ -247,6 +248,11 @@ extern const struct svc_version nfs4_callback_version4;
 /* fs_context.c */
 extern struct file_system_type nfs_fs_type;
 
+/* fsinfo.c */
+#ifdef CONFIG_FSINFO
+extern int nfs_fsinfo(struct path *path, struct fsinfo_context *ctx);
+#endif
+
 /* pagelist.c */
 extern int __init nfs_init_nfspagecache(void);
 extern void nfs_destroy_nfspagecache(void);
diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
index 1475f932d7da..cd38da87cbd3 100644
--- a/fs/nfs/nfs4super.c
+++ b/fs/nfs/nfs4super.c
@@ -26,6 +26,9 @@ static const struct super_operations nfs4_sops = {
 	.write_inode	= nfs4_write_inode,
 	.drop_inode	= nfs_drop_inode,
 	.statfs		= nfs_statfs,
+#ifdef CONFIG_FSINFO
+	.fsinfo		= nfs_fsinfo,
+#endif
 	.evict_inode	= nfs4_evict_inode,
 	.umount_begin	= nfs_umount_begin,
 	.show_options	= nfs_show_options,
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index dada09b391c6..27ac751d3789 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -76,6 +76,9 @@ const struct super_operations nfs_sops = {
 	.write_inode	= nfs_write_inode,
 	.drop_inode	= nfs_drop_inode,
 	.statfs		= nfs_statfs,
+#ifdef CONFIG_FSINFO
+	.fsinfo		= nfs_fsinfo,
+#endif
 	.evict_inode	= nfs_evict_inode,
 	.umount_begin	= nfs_umount_begin,
 	.show_options	= nfs_show_options,
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index 4cfb71227eff..80f1ae8bd17d 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -44,6 +44,11 @@
 
 #define FSINFO_ATTR_EXT4_TIMESTAMPS	0x400	/* Ext4 superblock timestamps */
 
+#define FSINFO_ATTR_NFS_INFO		0x500	/* Information about an NFS mount */
+#define FSINFO_ATTR_NFS_SERVER_NAME	0x501	/* Name of the server (string) */
+#define FSINFO_ATTR_NFS_SERVER_ADDRESSES 0x502	/* List of addresses of the server */
+#define FSINFO_ATTR_NFS_GSSAPI_NAME	0x503	/* GSSAPI acceptor name */
+
 /*
  * Optional fsinfo() parameter structure.
  *
@@ -339,4 +344,28 @@ struct fsinfo_ext4_timestamps {
 
 #define FSINFO_ATTR_EXT4_TIMESTAMPS__STRUCT struct fsinfo_ext4_timestamps
 
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_NFS_INFO).
+ *
+ * Get information about an NFS mount.
+ */
+struct fsinfo_nfs_info {
+	__u32		version;
+	__u32		minor_version;
+	__u32		transport_proto;
+};
+
+#define FSINFO_ATTR_NFS_INFO__STRUCT struct fsinfo_nfs_info
+
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_NFS_SERVER_ADDRESSES).
+ *
+ * Get the addresses of the server for an NFS mount.
+ */
+struct fsinfo_nfs_server_address {
+	struct __kernel_sockaddr_storage address;
+};
+
+#define FSINFO_ATTR_NFS_SERVER_ADDRESSES__STRUCT struct fsinfo_nfs_server_address
+
 #endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/include/uapi/linux/windows.h b/include/uapi/linux/windows.h
new file mode 100644
index 000000000000..17efb9a40529
--- /dev/null
+++ b/include/uapi/linux/windows.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Common windows attributes
+ */
+#ifndef _UAPI_LINUX_WINDOWS_H
+#define _UAPI_LINUX_WINDOWS_H
+
+/*
+ * File Attribute flags
+ */
+#define ATTR_READONLY		0x0001
+#define ATTR_HIDDEN		0x0002
+#define ATTR_SYSTEM		0x0004
+#define ATTR_VOLUME		0x0008
+#define ATTR_DIRECTORY		0x0010
+#define ATTR_ARCHIVE		0x0020
+#define ATTR_DEVICE		0x0040
+#define ATTR_NORMAL		0x0080
+#define ATTR_TEMPORARY		0x0100
+#define ATTR_SPARSE		0x0200
+#define ATTR_REPARSE		0x0400
+#define ATTR_COMPRESSED		0x0800
+#define ATTR_OFFLINE		0x1000	/* ie file not immediately available -
+					   on offline storage */
+#define ATTR_NOT_CONTENT_INDEXED 0x2000
+#define ATTR_ENCRYPTED		0x4000
+#define ATTR_POSIX_SEMANTICS	0x01000000
+#define ATTR_BACKUP_SEMANTICS	0x02000000
+#define ATTR_DELETE_ON_CLOSE	0x04000000
+#define ATTR_SEQUENTIAL_SCAN	0x08000000
+#define ATTR_RANDOM_ACCESS	0x10000000
+#define ATTR_NO_BUFFERING	0x20000000
+#define ATTR_WRITE_THROUGH	0x80000000
+
+#endif /* _UAPI_LINUX_WINDOWS_H */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index 6ad1128a3e1d..8e19cdc18d91 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -418,6 +418,40 @@ static void dump_ext4_fsinfo_timestamps(void *reply, unsigned int size)
 	printf("\tlast-err: %s\n", dump_ext4_time(buffer, r->last_error_time));
 }
 
+static void dump_nfs_fsinfo_info(void *reply, unsigned int size)
+{
+	struct fsinfo_nfs_info *r = reply;
+
+	printf("ver=%u.%u proto=%u\n", r->version, r->minor_version, r->transport_proto);
+}
+
+static void dump_nfs_fsinfo_server_addresses(void *reply, unsigned int size)
+{
+	struct fsinfo_nfs_server_address *r = reply;
+	struct sockaddr_storage *ss = (struct sockaddr_storage *)&r->address;
+	struct sockaddr_in6 *sin6;
+	struct sockaddr_in *sin;
+	char buf[1024];
+
+	switch (ss->ss_family) {
+	case AF_INET:
+		sin = (struct sockaddr_in *)ss;
+		if (!inet_ntop(AF_INET, &sin->sin_addr, buf, sizeof(buf)))
+			break;
+		printf("%5u %s\n", ntohs(sin->sin_port), buf);
+		return;
+	case AF_INET6:
+		sin6 = (struct sockaddr_in6 *)ss;
+		if (!inet_ntop(AF_INET6, &sin6->sin6_addr, buf, sizeof(buf)))
+			break;
+		printf("%5u %s\n", ntohs(sin6->sin6_port), buf);
+		return;
+	default:
+		printf("family=%u\n", ss->ss_family);
+		return;
+	}
+}
+
 static void dump_string(void *reply, unsigned int size)
 {
 	char *s = reply, *p;
@@ -506,6 +540,10 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
 	FSINFO_STRING	(FSINFO_ATTR_AFS_SERVER_NAME,	string),
 	FSINFO_LIST_N	(FSINFO_ATTR_AFS_SERVER_ADDRESSES, afs_fsinfo_server_address),
 	FSINFO_VSTRUCT	(FSINFO_ATTR_EXT4_TIMESTAMPS,	ext4_fsinfo_timestamps),
+	FSINFO_VSTRUCT	(FSINFO_ATTR_NFS_INFO,		nfs_fsinfo_info),
+	FSINFO_STRING	(FSINFO_ATTR_NFS_SERVER_NAME,	string),
+	FSINFO_LIST	(FSINFO_ATTR_NFS_SERVER_ADDRESSES, nfs_fsinfo_server_addresses),
+	FSINFO_STRING	(FSINFO_ATTR_NFS_GSSAPI_NAME,	string),
 	{}
 };
 

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