diff --git a/third_party/linux/external/0002-fsinfo-Add-fsinfo-syscall-to-query-filesystem-inform.patch b/third_party/linux/external/0002-fsinfo-Add-fsinfo-syscall-to-query-filesystem-inform.patch
new file mode 100644
index 0000000..7b5147f
--- /dev/null
+++ b/third_party/linux/external/0002-fsinfo-Add-fsinfo-syscall-to-query-filesystem-inform.patch
@@ -0,0 +1,1953 @@
+From 5837a1c690d51c270c8f04029530f2ce6856739a Mon Sep 17 00:00:00 2001
+From: David Howells <dhowells@redhat.com>
+Date: Fri, 6 Mar 2020 14:59:51 +0000
+Subject: [PATCH 2/3] fsinfo: Add fsinfo() syscall to query filesystem
+ information
+
+Add a system call to allow filesystem information to be queried.  A request
+value can be given to indicate the desired attribute.  Support is provided
+for enumerating multi-value attributes.
+
+===============
+NEW SYSTEM CALL
+===============
+
+The new system call looks like:
+
+	int ret = fsinfo(int dfd,
+			 const char *pathname,
+			 const struct fsinfo_params *params,
+			 size_t params_size,
+			 void *result_buffer,
+			 size_t result_buf_size);
+
+The params parameter optionally points to a block of parameters:
+
+	struct fsinfo_params {
+		__u64	resolve_flags;
+		__u32	at_flags;
+		__u32	flags;
+		__u32	request;
+		__u32	Nth;
+		__u32	Mth;
+	};
+
+If params is NULL, the default is that params->request is
+FSINFO_ATTR_STATFS and all the other fields are 0.  params_size indicates
+the size of the parameter struct.  If the parameter block is short compared
+to what the kernel expects, the missing length will be set to 0; if the
+parameter block is longer, an error will be given if the excess is not all
+zeros.
+
+The object to be queried is specified as follows - part param->flags
+indicates the type of reference:
+
+ (1) FSINFO_FLAGS_QUERY_PATH - dfd, pathname and at_flags indicate a
+     filesystem object to query.
+
+     There is no separate system call providing an analogue of lstat() -
+     AT_SYMLINK_NOFOLLOW should be set in at_flags instead.
+     AT_NO_AUTOMOUNT can also be used to an allow automount point to be
+     queried without triggering it.
+
+     RESOLVE_* flags can also be set in resolve_flags to further restrict
+     the patchwalk.
+
+ (2) FSINFO_FLAGS_QUERY_FD - dfd indicates a file descriptor pointing to
+     the filesystem object to query.  pathname should be NULL.
+
+ (3) FSINFO_FLAGS_QUERY_MOUNT - pathname indicates the numeric ID of the
+     mountpoint to query as a string.  dfd is used to constrain which
+     mounts can be accessed.  If dfd is AT_FDCWD, the mount must be within
+     the subtree rooted at chroot, otherwise the mount must be within the
+     subtree rooted at the directory specified by dfd.
+
+ (4) In the future FSINFO_FLAGS_QUERY_FSCONTEXT will be added - dfd will
+     indicate a context handle fd obtained from fsopen() or fspick(),
+     allowing that to be queried before the target superblock is attached
+     to the filesystem or even created.
+
+params->request indicates the attribute/attributes to be queried.  This can
+be one of:
+
+	FSINFO_ATTR_STATFS		- statfs-style info
+	FSINFO_ATTR_IDS			- Filesystem IDs
+	FSINFO_ATTR_LIMITS		- Filesystem limits
+	FSINFO_ATTR_SUPPORTS		- Support for statx, ioctl, etc.
+	FSINFO_ATTR_TIMESTAMP_INFO	- Inode timestamp info
+	FSINFO_ATTR_VOLUME_ID		- Volume ID (string)
+	FSINFO_ATTR_VOLUME_UUID		- Volume UUID
+	FSINFO_ATTR_VOLUME_NAME		- Volume name (string)
+	FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO - Information about attr Nth
+	FSINFO_ATTR_FSINFO_ATTRIBUTES	- List of supported attrs
+
+Some attributes (such as the servers backing a network filesystem) can have
+multiple values.  These can be enumerated by setting params->Nth and
+params->Mth to 0, 1, ... until ENODATA is returned.
+
+result_buffer and result_buf_size point to the reply buffer.  The buffer is
+filled up to the specified size, even if this means truncating the reply.
+The size of the full reply is returned, irrespective of the amount data
+that was copied.  In future versions, this will allow extra fields to be
+tacked on to the end of the reply, but anyone not expecting them will only
+get the subset they're expecting.  If either buffer of result_buf_size are
+0, no copy will take place and the data size will be returned.
+
+Ported to 5.10 by Lorenz Brun <lorenz@nexantic.com>
+
+Signed-off-by: David Howells <dhowells@redhat.com>
+cc: linux-api@vger.kernel.org
+---
+ arch/alpha/kernel/syscalls/syscall.tbl      |   1 +
+ arch/arm/tools/syscall.tbl                  |   1 +
+ arch/arm64/include/asm/unistd.h             |   2 +-
+ arch/arm64/include/asm/unistd32.h           |   2 +
+ arch/ia64/kernel/syscalls/syscall.tbl       |   1 +
+ arch/m68k/kernel/syscalls/syscall.tbl       |   1 +
+ arch/microblaze/kernel/syscalls/syscall.tbl |   1 +
+ arch/mips/kernel/syscalls/syscall_n32.tbl   |   1 +
+ arch/mips/kernel/syscalls/syscall_n64.tbl   |   1 +
+ arch/mips/kernel/syscalls/syscall_o32.tbl   |   1 +
+ arch/parisc/kernel/syscalls/syscall.tbl     |   1 +
+ arch/powerpc/kernel/syscalls/syscall.tbl    |   1 +
+ arch/s390/kernel/syscalls/syscall.tbl       |   1 +
+ arch/sh/kernel/syscalls/syscall.tbl         |   1 +
+ arch/sparc/kernel/syscalls/syscall.tbl      |   1 +
+ arch/x86/entry/syscalls/syscall_32.tbl      |   1 +
+ arch/x86/entry/syscalls/syscall_64.tbl      |   1 +
+ arch/xtensa/kernel/syscalls/syscall.tbl     |   1 +
+ fs/Kconfig                                  |   7 +
+ fs/Makefile                                 |   1 +
+ fs/fsinfo.c                                 | 596 ++++++++++++++++++
+ include/linux/fs.h                          |   4 +
+ include/linux/fsinfo.h                      |  74 +++
+ include/linux/syscalls.h                    |   4 +
+ include/uapi/asm-generic/unistd.h           |   4 +-
+ include/uapi/linux/fsinfo.h                 | 189 ++++++
+ kernel/sys_ni.c                             |   1 +
+ samples/vfs/Makefile                        |   2 +-
+ samples/vfs/test-fsinfo.c                   | 646 ++++++++++++++++++++
+ 29 files changed, 1545 insertions(+), 3 deletions(-)
+ create mode 100644 fs/fsinfo.c
+ create mode 100644 include/linux/fsinfo.h
+ create mode 100644 include/uapi/linux/fsinfo.h
+ create mode 100644 samples/vfs/test-fsinfo.c
+
+diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
+index ee7b01bb7346c..c955e31d57289 100644
+--- a/arch/alpha/kernel/syscalls/syscall.tbl
++++ b/arch/alpha/kernel/syscalls/syscall.tbl
+@@ -480,3 +480,4 @@
+ 548	common	pidfd_getfd			sys_pidfd_getfd
+ 549	common	faccessat2			sys_faccessat2
+ 550	common	process_madvise			sys_process_madvise
++551	common	fsinfo				sys_fsinfo
+diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
+index d056a548358ea..308dfe68d892c 100644
+--- a/arch/arm/tools/syscall.tbl
++++ b/arch/arm/tools/syscall.tbl
+@@ -454,3 +454,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
+index b3b2019f8d16b..86a9d7b3eabe9 100644
+--- a/arch/arm64/include/asm/unistd.h
++++ b/arch/arm64/include/asm/unistd.h
+@@ -38,7 +38,7 @@
+ #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
+ #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
+ 
+-#define __NR_compat_syscalls		441
++#define __NR_compat_syscalls		442
+ #endif
+ 
+ #define __ARCH_WANT_SYS_CLONE
+diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
+index 107f08e03b9fd..20650e0edacb2 100644
+--- a/arch/arm64/include/asm/unistd32.h
++++ b/arch/arm64/include/asm/unistd32.h
+@@ -889,6 +889,8 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd)
+ __SYSCALL(__NR_faccessat2, sys_faccessat2)
+ #define __NR_process_madvise 440
+ __SYSCALL(__NR_process_madvise, sys_process_madvise)
++#define __NR_fsinfo 441
++__SYSCALL(__NR_fsinfo, sys_fsinfo)
+ 
+ /*
+  * Please add new compat syscalls above this comment and update
+diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
+index b96ed8b8a5089..548428f7b76c7 100644
+--- a/arch/ia64/kernel/syscalls/syscall.tbl
++++ b/arch/ia64/kernel/syscalls/syscall.tbl
+@@ -361,3 +361,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
+index 625fb6d328424..3dd9c1f0815ce 100644
+--- a/arch/m68k/kernel/syscalls/syscall.tbl
++++ b/arch/m68k/kernel/syscalls/syscall.tbl
+@@ -440,3 +440,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
+index aae729c95cf99..420a6d0b01004 100644
+--- a/arch/microblaze/kernel/syscalls/syscall.tbl
++++ b/arch/microblaze/kernel/syscalls/syscall.tbl
+@@ -446,3 +446,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
+index 32817c954435d..01420fe120bab 100644
+--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
++++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
+@@ -379,3 +379,4 @@
+ 438	n32	pidfd_getfd			sys_pidfd_getfd
+ 439	n32	faccessat2			sys_faccessat2
+ 440	n32	process_madvise			sys_process_madvise
++441	n32	fsinfo				sys_fsinfo
+diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
+index 9e4ea3c31b1ce..6c319c38779e9 100644
+--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
++++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
+@@ -355,3 +355,4 @@
+ 438	n64	pidfd_getfd			sys_pidfd_getfd
+ 439	n64	faccessat2			sys_faccessat2
+ 440	n64	process_madvise			sys_process_madvise
++441	n64	fsinfo				sys_fsinfo
+diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
+index 29f5f28cf5cea..46d4aa7ecb306 100644
+--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
++++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
+@@ -428,3 +428,4 @@
+ 438	o32	pidfd_getfd			sys_pidfd_getfd
+ 439	o32	faccessat2			sys_faccessat2
+ 440	o32	process_madvise			sys_process_madvise
++441	o32	fsinfo				sys_fsinfo
+diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
+index f375ea528e59c..008282637f6af 100644
+--- a/arch/parisc/kernel/syscalls/syscall.tbl
++++ b/arch/parisc/kernel/syscalls/syscall.tbl
+@@ -438,3 +438,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
+index 1275daec7fec3..85da23afb3535 100644
+--- a/arch/powerpc/kernel/syscalls/syscall.tbl
++++ b/arch/powerpc/kernel/syscalls/syscall.tbl
+@@ -530,3 +530,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
+index 28c1680004834..83fdaebbf0b08 100644
+--- a/arch/s390/kernel/syscalls/syscall.tbl
++++ b/arch/s390/kernel/syscalls/syscall.tbl
+@@ -443,3 +443,4 @@
+ 438  common	pidfd_getfd		sys_pidfd_getfd			sys_pidfd_getfd
+ 439  common	faccessat2		sys_faccessat2			sys_faccessat2
+ 440  common	process_madvise		sys_process_madvise		sys_process_madvise
++441	common	fsinfo			sys_fsinfo			sys_fsinfo
+diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
+index 783738448ff55..e1f52ffa86bb8 100644
+--- a/arch/sh/kernel/syscalls/syscall.tbl
++++ b/arch/sh/kernel/syscalls/syscall.tbl
+@@ -443,3 +443,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
+index 78160260991be..1f42dc9965c23 100644
+--- a/arch/sparc/kernel/syscalls/syscall.tbl
++++ b/arch/sparc/kernel/syscalls/syscall.tbl
+@@ -486,3 +486,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
+index 0d0667a9fbd70..70da9bad3f79d 100644
+--- a/arch/x86/entry/syscalls/syscall_32.tbl
++++ b/arch/x86/entry/syscalls/syscall_32.tbl
+@@ -445,3 +445,4 @@
+ 438	i386	pidfd_getfd		sys_pidfd_getfd
+ 439	i386	faccessat2		sys_faccessat2
+ 440	i386	process_madvise		sys_process_madvise
++441	i386	fsinfo			sys_fsinfo
+diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
+index 379819244b91d..94a51b78e85ed 100644
+--- a/arch/x86/entry/syscalls/syscall_64.tbl
++++ b/arch/x86/entry/syscalls/syscall_64.tbl
+@@ -362,6 +362,7 @@
+ 438	common	pidfd_getfd		sys_pidfd_getfd
+ 439	common	faccessat2		sys_faccessat2
+ 440	common	process_madvise		sys_process_madvise
++441	common	fsinfo			sys_fsinfo
+ 
+ #
+ # Due to a historical design error, certain syscalls are numbered differently
+diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
+index b070f272995d6..2723c2f43c59a 100644
+--- a/arch/xtensa/kernel/syscalls/syscall.tbl
++++ b/arch/xtensa/kernel/syscalls/syscall.tbl
+@@ -411,3 +411,4 @@
+ 438	common	pidfd_getfd			sys_pidfd_getfd
+ 439	common	faccessat2			sys_faccessat2
+ 440	common	process_madvise			sys_process_madvise
++441	common	fsinfo				sys_fsinfo
+diff --git a/fs/Kconfig b/fs/Kconfig
+index aa4c122823018..b84156272983b 100644
+--- a/fs/Kconfig
++++ b/fs/Kconfig
+@@ -15,6 +15,13 @@ config VALIDATE_FS_PARSER
+ 	  Enable this to perform validation of the parameter description for a
+ 	  filesystem when it is registered.
+ 
++config FSINFO
++	bool "Enable the fsinfo() system call"
++	help
++	  Enable the file system information querying system call to allow
++	  comprehensive information to be retrieved about a filesystem,
++	  superblock or mount object.
++
+ if BLOCK
+ 
+ config FS_IOMAP
+diff --git a/fs/Makefile b/fs/Makefile
+index 999d1a23f036c..02da949de3b42 100644
+--- a/fs/Makefile
++++ b/fs/Makefile
+@@ -54,6 +54,7 @@ obj-$(CONFIG_COREDUMP)		+= coredump.o
+ obj-$(CONFIG_SYSCTL)		+= drop_caches.o
+ 
+ obj-$(CONFIG_FHANDLE)		+= fhandle.o
++obj-$(CONFIG_FSINFO)		+= fsinfo.o
+ obj-y				+= iomap/
+ 
+ obj-y				+= quota/
+diff --git a/fs/fsinfo.c b/fs/fsinfo.c
+new file mode 100644
+index 0000000000000..7d9c73e9cbdef
+--- /dev/null
++++ b/fs/fsinfo.c
+@@ -0,0 +1,596 @@
++// SPDX-License-Identifier: GPL-2.0
++/* Filesystem information query.
++ *
++ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
++ * Written by David Howells (dhowells@redhat.com)
++ */
++#include <linux/syscalls.h>
++#include <linux/fs.h>
++#include <linux/file.h>
++#include <linux/mount.h>
++#include <linux/namei.h>
++#include <linux/statfs.h>
++#include <linux/security.h>
++#include <linux/uaccess.h>
++#include <linux/fsinfo.h>
++#include <uapi/linux/mount.h>
++#include "internal.h"
++
++/**
++ * fsinfo_opaque - Store opaque blob as an fsinfo attribute value.
++ * @s: The blob to store (may be NULL)
++ * @ctx: The parameter context
++ * @len: The length of the blob
++ */
++int fsinfo_opaque(const void *s, struct fsinfo_context *ctx, unsigned int len)
++{
++	void *p = ctx->buffer;
++	int ret = 0;
++
++	if (s) {
++		if (!ctx->want_size_only)
++			memcpy(p, s, len);
++		ret = len;
++	}
++
++	return ret;
++}
++EXPORT_SYMBOL(fsinfo_opaque);
++
++/**
++ * fsinfo_string - Store a NUL-terminated string as an fsinfo attribute value.
++ * @s: The string to store (may be NULL)
++ * @ctx: The parameter context
++ */
++int fsinfo_string(const char *s, struct fsinfo_context *ctx)
++{
++	if (!s)
++		return 1;
++	return fsinfo_opaque(s, ctx, min_t(size_t, strlen(s) + 1, ctx->buf_size));
++}
++EXPORT_SYMBOL(fsinfo_string);
++
++/*
++ * Get basic filesystem stats from statfs.
++ */
++static int fsinfo_generic_statfs(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_statfs *p = ctx->buffer;
++	struct kstatfs buf;
++	int ret;
++
++	ret = vfs_statfs(path, &buf);
++	if (ret < 0)
++		return ret;
++
++	p->f_blocks.lo	= buf.f_blocks;
++	p->f_bfree.lo	= buf.f_bfree;
++	p->f_bavail.lo	= buf.f_bavail;
++	p->f_files.lo	= buf.f_files;
++	p->f_ffree.lo	= buf.f_ffree;
++	p->f_favail.lo	= buf.f_ffree;
++	p->f_bsize	= buf.f_bsize;
++	p->f_frsize	= buf.f_frsize;
++	return sizeof(*p);
++}
++
++static int fsinfo_generic_ids(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_ids *p = ctx->buffer;
++	struct super_block *sb;
++	struct kstatfs buf;
++	int ret;
++
++	ret = vfs_statfs(path, &buf);
++	if (ret < 0 && ret != -ENOSYS)
++		return ret;
++	if (ret == 0)
++		memcpy(&p->f_fsid, &buf.f_fsid, sizeof(p->f_fsid));
++
++	sb = path->dentry->d_sb;
++	p->f_fstype	= sb->s_magic;
++	p->f_dev_major	= MAJOR(sb->s_dev);
++	p->f_dev_minor	= MINOR(sb->s_dev);
++	p->f_sb_id	= sb->s_unique_id;
++	strlcpy(p->f_fs_name, sb->s_type->name, sizeof(p->f_fs_name));
++	return sizeof(*p);
++}
++
++int fsinfo_generic_limits(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_limits *p = ctx->buffer;
++	struct super_block *sb = path->dentry->d_sb;
++
++	p->max_file_size.hi	= 0;
++	p->max_file_size.lo	= sb->s_maxbytes;
++	p->max_ino.hi		= 0;
++	p->max_ino.lo		= UINT_MAX;
++	p->max_hard_links	= sb->s_max_links;
++	p->max_uid		= UINT_MAX;
++	p->max_gid		= UINT_MAX;
++	p->max_projid		= UINT_MAX;
++	p->max_filename_len	= NAME_MAX;
++	p->max_symlink_len	= PATH_MAX;
++	p->max_xattr_name_len	= XATTR_NAME_MAX;
++	p->max_xattr_body_len	= XATTR_SIZE_MAX;
++	p->max_dev_major	= 0xffffff;
++	p->max_dev_minor	= 0xff;
++	return sizeof(*p);
++}
++EXPORT_SYMBOL(fsinfo_generic_limits);
++
++int fsinfo_generic_supports(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_supports *p = ctx->buffer;
++	struct super_block *sb = path->dentry->d_sb;
++
++	p->stx_mask = STATX_BASIC_STATS;
++	if (sb->s_d_op && sb->s_d_op->d_automount)
++		p->stx_attributes |= STATX_ATTR_AUTOMOUNT;
++	return sizeof(*p);
++}
++EXPORT_SYMBOL(fsinfo_generic_supports);
++
++static const struct fsinfo_timestamp_info fsinfo_default_timestamp_info = {
++	.atime = {
++		.minimum	= S64_MIN,
++		.maximum	= S64_MAX,
++		.gran_mantissa	= 1,
++		.gran_exponent	= 0,
++	},
++	.mtime = {
++		.minimum	= S64_MIN,
++		.maximum	= S64_MAX,
++		.gran_mantissa	= 1,
++		.gran_exponent	= 0,
++	},
++	.ctime = {
++		.minimum	= S64_MIN,
++		.maximum	= S64_MAX,
++		.gran_mantissa	= 1,
++		.gran_exponent	= 0,
++	},
++	.btime = {
++		.minimum	= S64_MIN,
++		.maximum	= S64_MAX,
++		.gran_mantissa	= 1,
++		.gran_exponent	= 0,
++	},
++};
++
++int fsinfo_generic_timestamp_info(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_timestamp_info *p = ctx->buffer;
++	struct super_block *sb = path->dentry->d_sb;
++	s8 exponent;
++
++	*p = fsinfo_default_timestamp_info;
++
++	if (sb->s_time_gran < 1000000000) {
++		if (sb->s_time_gran < 1000)
++			exponent = -9;
++		else if (sb->s_time_gran < 1000000)
++			exponent = -6;
++		else
++			exponent = -3;
++
++		p->atime.gran_exponent = exponent;
++		p->mtime.gran_exponent = exponent;
++		p->ctime.gran_exponent = exponent;
++		p->btime.gran_exponent = exponent;
++	}
++
++	return sizeof(*p);
++}
++EXPORT_SYMBOL(fsinfo_generic_timestamp_info);
++
++static int fsinfo_generic_volume_uuid(struct path *path, struct fsinfo_context *ctx)
++{
++	struct fsinfo_volume_uuid *p = ctx->buffer;
++	struct super_block *sb = path->dentry->d_sb;
++
++	memcpy(p, &sb->s_uuid, sizeof(*p));
++	return sizeof(*p);
++}
++
++static int fsinfo_generic_volume_id(struct path *path, struct fsinfo_context *ctx)
++{
++	return fsinfo_string(path->dentry->d_sb->s_id, ctx);
++}
++
++static const struct fsinfo_attribute fsinfo_common_attributes[] = {
++	FSINFO_VSTRUCT	(FSINFO_ATTR_STATFS,		fsinfo_generic_statfs),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_IDS,		fsinfo_generic_ids),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_LIMITS,		fsinfo_generic_limits),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_SUPPORTS,		fsinfo_generic_supports),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_TIMESTAMP_INFO,	fsinfo_generic_timestamp_info),
++	FSINFO_STRING	(FSINFO_ATTR_VOLUME_ID,		fsinfo_generic_volume_id),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_VOLUME_UUID,	fsinfo_generic_volume_uuid),
++
++	FSINFO_LIST	(FSINFO_ATTR_FSINFO_ATTRIBUTES,	(void *)123UL),
++	FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, (void *)123UL),
++	{}
++};
++
++/*
++ * Determine an attribute's minimum buffer size and, if the buffer is large
++ * enough, get the attribute value.
++ */
++static int fsinfo_get_this_attribute(struct path *path,
++				     struct fsinfo_context *ctx,
++				     const struct fsinfo_attribute *attr)
++{
++	int buf_size;
++
++	if (ctx->Nth != 0 && !(attr->flags & (FSINFO_FLAGS_N | FSINFO_FLAGS_NM)))
++		return -ENODATA;
++	if (ctx->Mth != 0 && !(attr->flags & FSINFO_FLAGS_NM))
++		return -ENODATA;
++
++	switch (attr->type) {
++	case FSINFO_TYPE_VSTRUCT:
++		ctx->clear_tail = true;
++		buf_size = attr->size;
++		break;
++	case FSINFO_TYPE_STRING:
++	case FSINFO_TYPE_OPAQUE:
++	case FSINFO_TYPE_LIST:
++		buf_size = 4096;
++		break;
++	default:
++		return -ENOPKG;
++	}
++
++	if (ctx->buf_size < buf_size)
++		return buf_size;
++
++	return attr->get(path, ctx);
++}
++
++static void fsinfo_attributes_insert(struct fsinfo_context *ctx,
++				     const struct fsinfo_attribute *attr)
++{
++	__u32 *p = ctx->buffer;
++	unsigned int i;
++
++	if (ctx->usage >= ctx->buf_size ||
++	    ctx->buf_size - ctx->usage < sizeof(__u32)) {
++		ctx->usage += sizeof(__u32);
++		return;
++	}
++
++	for (i = 0; i < ctx->usage / sizeof(__u32); i++)
++		if (p[i] == attr->attr_id)
++			return;
++
++	p[i] = attr->attr_id;
++	ctx->usage += sizeof(__u32);
++}
++
++static int fsinfo_list_attributes(struct path *path,
++				  struct fsinfo_context *ctx,
++				  const struct fsinfo_attribute *attributes)
++{
++	const struct fsinfo_attribute *a;
++
++	for (a = attributes; a->get; a++)
++		fsinfo_attributes_insert(ctx, a);
++	return -EOPNOTSUPP; /* We want to go through all the lists */
++}
++
++static int fsinfo_get_attribute_info(struct path *path,
++				     struct fsinfo_context *ctx,
++				     const struct fsinfo_attribute *attributes)
++{
++	const struct fsinfo_attribute *a;
++	struct fsinfo_attribute_info *p = ctx->buffer;
++
++	if (!ctx->buf_size)
++		return sizeof(*p);
++
++	for (a = attributes; a->get; a++) {
++		if (a->attr_id == ctx->Nth) {
++			p->attr_id	= a->attr_id;
++			p->type		= a->type;
++			p->flags	= a->flags;
++			p->size		= a->size;
++			p->size		= a->size;
++			return sizeof(*p);
++		}
++	}
++	return -EOPNOTSUPP; /* We want to go through all the lists */
++}
++
++/**
++ * fsinfo_get_attribute - Look up and handle an attribute
++ * @path: The object to query
++ * @params: Parameters to define a request and place to store result
++ * @attributes: List of attributes to search.
++ *
++ * Look through a list of attributes for one that matches the requested
++ * attribute then call the handler for it.
++ */
++int fsinfo_get_attribute(struct path *path, struct fsinfo_context *ctx,
++			 const struct fsinfo_attribute *attributes)
++{
++	const struct fsinfo_attribute *a;
++
++	switch (ctx->requested_attr) {
++	case FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO:
++		return fsinfo_get_attribute_info(path, ctx, attributes);
++	case FSINFO_ATTR_FSINFO_ATTRIBUTES:
++		return fsinfo_list_attributes(path, ctx, attributes);
++	default:
++		for (a = attributes; a->get; a++)
++			if (a->attr_id == ctx->requested_attr)
++				return fsinfo_get_this_attribute(path, ctx, a);
++		return -EOPNOTSUPP;
++	}
++}
++EXPORT_SYMBOL(fsinfo_get_attribute);
++
++/**
++ * generic_fsinfo - Handle an fsinfo attribute generically
++ * @path: The object to query
++ * @params: Parameters to define a request and place to store result
++ */
++static int fsinfo_call(struct path *path, struct fsinfo_context *ctx)
++{
++	int ret;
++
++	if (path->dentry->d_sb->s_op->fsinfo) {
++		ret = path->dentry->d_sb->s_op->fsinfo(path, ctx);
++		if (ret != -EOPNOTSUPP)
++			return ret;
++	}
++	ret = fsinfo_get_attribute(path, ctx, fsinfo_common_attributes);
++	if (ret != -EOPNOTSUPP)
++		return ret;
++
++	switch (ctx->requested_attr) {
++	case FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO:
++		return -ENODATA;
++	case FSINFO_ATTR_FSINFO_ATTRIBUTES:
++		return ctx->usage;
++	default:
++		return -EOPNOTSUPP;
++	}
++}
++
++/**
++ * vfs_fsinfo - Retrieve filesystem information
++ * @path: The object to query
++ * @params: Parameters to define a request and place to store result
++ *
++ * Get an attribute on a filesystem or an object within a filesystem.  The
++ * filesystem attribute to be queried is indicated by @ctx->requested_attr, and
++ * if it's a multi-valued attribute, the particular value is selected by
++ * @ctx->Nth and then @ctx->Mth.
++ *
++ * For common attributes, a value may be fabricated if it is not supported by
++ * the filesystem.
++ *
++ * On success, the size of the attribute's value is returned (0 is a valid
++ * size).  A buffer will have been allocated and will be pointed to by
++ * @ctx->buffer.  The caller must free this with kvfree().
++ *
++ * Errors can also be returned: -ENOMEM if a buffer cannot be allocated, -EPERM
++ * or -EACCES if permission is denied by the LSM, -EOPNOTSUPP if an attribute
++ * doesn't exist for the specified object or -ENODATA if the attribute exists,
++ * but the Nth,Mth value does not exist.  -EMSGSIZE indicates that the value is
++ * unmanageable internally and -ENOPKG indicates other internal failure.
++ *
++ * Errors such as -EIO may also come from attempts to access media or servers
++ * to obtain the requested information if it's not immediately to hand.
++ *
++ * [*] Note that the caller may set @ctx->want_size_only if it only wants the
++ *     size of the value and not the data.  If this is set, a buffer may not be
++ *     allocated under some circumstances.  This is intended for size query by
++ *     userspace.
++ *
++ * [*] Note that @ctx->clear_tail will be returned set if the data should be
++ *     padded out with zeros when writing it to userspace.
++ */
++static int vfs_fsinfo(struct path *path, struct fsinfo_context *ctx)
++{
++	struct dentry *dentry = path->dentry;
++	int ret;
++
++	ret = security_sb_statfs(dentry);
++	if (ret)
++		return ret;
++
++	/* Call the handler to find out the buffer size required. */
++	ctx->buf_size = 0;
++	ret = fsinfo_call(path, ctx);
++	if (ret < 0 || ctx->want_size_only)
++		return ret;
++	ctx->buf_size = ret;
++
++	do {
++		/* Allocate a buffer of the requested size. */
++		if (ctx->buf_size > INT_MAX)
++			return -EMSGSIZE;
++		ctx->buffer = kvzalloc(ctx->buf_size, GFP_KERNEL);
++		if (!ctx->buffer)
++			return -ENOMEM;
++
++		ctx->usage = 0;
++		ctx->skip = 0;
++		ret = fsinfo_call(path, ctx);
++		if (IS_ERR_VALUE((long)ret))
++			return ret;
++		if ((unsigned int)ret <= ctx->buf_size)
++			return ret; /* It fitted */
++
++		/* We need to resize the buffer */
++		ctx->buf_size = roundup(ret, PAGE_SIZE);
++		kvfree(ctx->buffer);
++		ctx->buffer = NULL;
++	} while (!signal_pending(current));
++
++	return -ERESTARTSYS;
++}
++
++static int vfs_fsinfo_path(int dfd, const char __user *pathname,
++			   const struct fsinfo_params *up,
++			   struct fsinfo_context *ctx)
++{
++	struct path path;
++	unsigned lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
++	int ret = -EINVAL;
++
++	if (up->resolve_flags & ~VALID_RESOLVE_FLAGS)
++		return -EINVAL;
++	if (up->at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
++			     AT_EMPTY_PATH))
++		return -EINVAL;
++
++	if (up->resolve_flags & RESOLVE_NO_XDEV)
++		lookup_flags |= LOOKUP_NO_XDEV;
++	if (up->resolve_flags & RESOLVE_NO_MAGICLINKS)
++		lookup_flags |= LOOKUP_NO_MAGICLINKS;
++	if (up->resolve_flags & RESOLVE_NO_SYMLINKS)
++		lookup_flags |= LOOKUP_NO_SYMLINKS;
++	if (up->resolve_flags & RESOLVE_BENEATH)
++		lookup_flags |= LOOKUP_BENEATH;
++	if (up->resolve_flags & RESOLVE_IN_ROOT)
++		lookup_flags |= LOOKUP_IN_ROOT;
++	if (up->at_flags & AT_SYMLINK_NOFOLLOW)
++		lookup_flags &= ~LOOKUP_FOLLOW;
++	if (up->at_flags & AT_NO_AUTOMOUNT)
++		lookup_flags &= ~LOOKUP_AUTOMOUNT;
++	if (up->at_flags & AT_EMPTY_PATH)
++		lookup_flags |= LOOKUP_EMPTY;
++
++retry:
++	ret = user_path_at(dfd, pathname, lookup_flags, &path);
++	if (ret)
++		goto out;
++
++	ret = vfs_fsinfo(&path, ctx);
++	path_put(&path);
++	if (retry_estale(ret, lookup_flags)) {
++		lookup_flags |= LOOKUP_REVAL;
++		goto retry;
++	}
++out:
++	return ret;
++}
++
++static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_context *ctx)
++{
++	struct fd f = fdget_raw(fd);
++	int ret = -EBADF;
++
++	if (f.file) {
++		ret = vfs_fsinfo(&f.file->f_path, ctx);
++		fdput(f);
++	}
++	return ret;
++}
++
++/**
++ * sys_fsinfo - System call to get filesystem information
++ * @dfd: Base directory to pathwalk from or fd referring to filesystem.
++ * @pathname: Filesystem to query or NULL.
++ * @params: Parameters to define request (NULL: FSINFO_ATTR_STATFS).
++ * @params_size: Size of parameter buffer.
++ * @result_buffer: Result buffer.
++ * @result_buf_size: Size of result buffer.
++ *
++ * Get information on a filesystem.  The filesystem attribute to be queried is
++ * indicated by @_params->request, and some of the attributes can have multiple
++ * values, indexed by @_params->Nth and @_params->Mth.  If @_params is NULL,
++ * then the 0th fsinfo_attr_statfs attribute is queried.  If an attribute does
++ * not exist, EOPNOTSUPP is returned; if the Nth,Mth value does not exist,
++ * ENODATA is returned.
++ *
++ * On success, the size of the attribute's value is returned.  If
++ * @result_buf_size is 0 or @result_buffer is NULL, only the size is returned.
++ * If the size of the value is larger than @result_buf_size, it will be
++ * truncated by the copy.  If the size of the value is smaller than
++ * @result_buf_size then the excess buffer space will be cleared.  The full
++ * size of the value will be returned, irrespective of how much data is
++ * actually placed in the buffer.
++ */
++SYSCALL_DEFINE6(fsinfo,
++		int, dfd,
++		const char __user *, pathname,
++		const struct fsinfo_params __user *, params,
++		size_t, params_size,
++		void __user *, result_buffer,
++		size_t, result_buf_size)
++{
++	struct fsinfo_context ctx;
++	struct fsinfo_params user_params;
++	unsigned int result_size;
++	void *r;
++	int ret;
++
++	if ((!params &&  params_size) ||
++	    ( params && !params_size) ||
++	    (!result_buffer &&  result_buf_size) ||
++	    ( result_buffer && !result_buf_size))
++		return -EINVAL;
++	if (result_buf_size > UINT_MAX)
++		return -EOVERFLOW;
++
++	memset(&ctx, 0, sizeof(ctx));
++	ctx.requested_attr	= FSINFO_ATTR_STATFS;
++	ctx.flags		= FSINFO_FLAGS_QUERY_PATH;
++	ctx.want_size_only	= (result_buf_size == 0);
++
++	if (params) {
++		ret = copy_struct_from_user(&user_params, sizeof(user_params),
++					    params, params_size);
++		if (ret < 0)
++			return ret;
++		if (user_params.flags & ~FSINFO_FLAGS_QUERY_MASK)
++			return -EINVAL;
++		ctx.flags = user_params.flags;
++		ctx.requested_attr = user_params.request;
++		ctx.Nth = user_params.Nth;
++		ctx.Mth = user_params.Mth;
++	}
++
++	switch (ctx.flags & FSINFO_FLAGS_QUERY_MASK) {
++	case FSINFO_FLAGS_QUERY_PATH:
++		ret = vfs_fsinfo_path(dfd, pathname, &user_params, &ctx);
++		break;
++	case FSINFO_FLAGS_QUERY_FD:
++		if (pathname)
++			return -EINVAL;
++		ret = vfs_fsinfo_fd(dfd, &ctx);
++		break;
++	default:
++		return -EINVAL;
++	}
++
++	if (ret < 0)
++		goto error;
++
++	r = ctx.buffer + ctx.skip;
++	result_size = min_t(size_t, ret, result_buf_size);
++	if (result_size > 0 &&
++	    copy_to_user(result_buffer, r, result_size) != 0) {
++		ret = -EFAULT;
++		goto error;
++	}
++
++	/* Clear any part of the buffer that we won't fill if we're putting a
++	 * struct in there.  Strings, opaque objects and arrays are expected to
++	 * be variable length.
++	 */
++	if (ctx.clear_tail &&
++	    result_buf_size > result_size &&
++	    clear_user(result_buffer + result_size,
++		       result_buf_size - result_size) != 0) {
++		ret = -EFAULT;
++		goto error;
++	}
++
++error:
++	kvfree(ctx.buffer);
++	return ret;
++}
+diff --git a/include/linux/fs.h b/include/linux/fs.h
+index e1325dec4fa86..2d5a2f709f322 100644
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -68,6 +68,7 @@ struct fsverity_info;
+ struct fsverity_operations;
+ struct fs_context;
+ struct fs_parameter_spec;
++struct fsinfo_context;
+ 
+ extern void __init inode_init(void);
+ extern void __init inode_init_early(void);
+@@ -1951,6 +1952,9 @@ struct super_operations {
+ 	int (*thaw_super) (struct super_block *);
+ 	int (*unfreeze_fs) (struct super_block *);
+ 	int (*statfs) (struct dentry *, struct kstatfs *);
++#ifdef CONFIG_FSINFO
++	int (*fsinfo)(struct path *, struct fsinfo_context *);
++#endif
+ 	int (*remount_fs) (struct super_block *, int *, char *);
+ 	void (*umount_begin) (struct super_block *);
+ 
+diff --git a/include/linux/fsinfo.h b/include/linux/fsinfo.h
+new file mode 100644
+index 0000000000000..a811d69b02ff0
+--- /dev/null
++++ b/include/linux/fsinfo.h
+@@ -0,0 +1,74 @@
++// SPDX-License-Identifier: GPL-2.0
++/* Filesystem information query
++ *
++ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
++ * Written by David Howells (dhowells@redhat.com)
++ */
++
++#ifndef _LINUX_FSINFO_H
++#define _LINUX_FSINFO_H
++
++#ifdef CONFIG_FSINFO
++
++#include <uapi/linux/fsinfo.h>
++
++struct path;
++
++#define FSINFO_NORMAL_ATTR_MAX_SIZE 4096
++
++struct fsinfo_context {
++	__u32		flags;		/* [in] FSINFO_FLAGS_* */
++	__u32		requested_attr;	/* [in] What is being asking for */
++	__u32		Nth;		/* [in] Instance of it (some may have multiple) */
++	__u32		Mth;		/* [in] Subinstance */
++	bool		want_size_only;	/* [in] Just want to know the size, not the data */
++	bool		clear_tail;	/* [out] T if tail of buffer should be cleared */
++	unsigned int	skip;		/* [out] Number of bytes to skip in buffer */
++	unsigned int	usage;		/* [tmp] Amount of buffer used (if large) */
++	unsigned int	buf_size;	/* [tmp] Size of ->buffer[] */
++	void		*buffer;	/* [out] The reply buffer */
++};
++
++/*
++ * A filesystem information attribute definition.
++ */
++struct fsinfo_attribute {
++	unsigned int		attr_id;	/* The ID of the attribute */
++	enum fsinfo_value_type	type:8;		/* The type of the attribute's value(s) */
++	unsigned int		flags:8;
++	unsigned int		size:16;	/* - Value size (FSINFO_STRUCT/LIST) */
++	int (*get)(struct path *path, struct fsinfo_context *params);
++};
++
++#define __FSINFO(A, T, S, G, F) \
++	{ .attr_id = A, .type = T, .flags = F, .size = S, .get = G }
++
++#define _FSINFO(A, T, S, G)	__FSINFO(A, T, S, G, 0)
++#define _FSINFO_N(A, T, S, G)	__FSINFO(A, T, S, G, FSINFO_FLAGS_N)
++#define _FSINFO_NM(A, T, S, G)	__FSINFO(A, T, S, G, FSINFO_FLAGS_NM)
++
++#define _FSINFO_VSTRUCT(A,S,G)	  _FSINFO   (A, FSINFO_TYPE_VSTRUCT, sizeof(S), G)
++#define _FSINFO_VSTRUCT_N(A,S,G)  _FSINFO_N (A, FSINFO_TYPE_VSTRUCT, sizeof(S), G)
++#define _FSINFO_VSTRUCT_NM(A,S,G) _FSINFO_NM(A, FSINFO_TYPE_VSTRUCT, sizeof(S), G)
++
++#define FSINFO_VSTRUCT(A,G)	_FSINFO_VSTRUCT   (A, A##__STRUCT, G)
++#define FSINFO_VSTRUCT_N(A,G)	_FSINFO_VSTRUCT_N (A, A##__STRUCT, G)
++#define FSINFO_VSTRUCT_NM(A,G)	_FSINFO_VSTRUCT_NM(A, A##__STRUCT, G)
++#define FSINFO_STRING(A,G)	_FSINFO   (A, FSINFO_TYPE_STRING, 0, G)
++#define FSINFO_STRING_N(A,G)	_FSINFO_N (A, FSINFO_TYPE_STRING, 0, G)
++#define FSINFO_STRING_NM(A,G)	_FSINFO_NM(A, FSINFO_TYPE_STRING, 0, G)
++#define FSINFO_OPAQUE(A,G)	_FSINFO   (A, FSINFO_TYPE_OPAQUE, 0, G)
++#define FSINFO_LIST(A,G)	_FSINFO   (A, FSINFO_TYPE_LIST, sizeof(A##__STRUCT), G)
++#define FSINFO_LIST_N(A,G)	_FSINFO_N (A, FSINFO_TYPE_LIST, sizeof(A##__STRUCT), G)
++
++extern int fsinfo_opaque(const void *, struct fsinfo_context *, unsigned int);
++extern int fsinfo_string(const char *, struct fsinfo_context *);
++extern int fsinfo_generic_timestamp_info(struct path *, struct fsinfo_context *);
++extern int fsinfo_generic_supports(struct path *, struct fsinfo_context *);
++extern int fsinfo_generic_limits(struct path *, struct fsinfo_context *);
++extern int fsinfo_get_attribute(struct path *, struct fsinfo_context *,
++				const struct fsinfo_attribute *);
++
++#endif /* CONFIG_FSINFO */
++
++#endif /* _LINUX_FSINFO_H */
+diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
+index 37bea07c12f21..e315f719899a1 100644
+--- a/include/linux/syscalls.h
++++ b/include/linux/syscalls.h
+@@ -47,6 +47,7 @@ struct stat64;
+ struct statfs;
+ struct statfs64;
+ struct statx;
++struct fsinfo_params;
+ struct sysinfo;
+ struct timespec;
+ struct __kernel_old_timeval;
+@@ -1008,6 +1009,9 @@ asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
+ 				       siginfo_t __user *info,
+ 				       unsigned int flags);
+ asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
++asmlinkage long sys_fsinfo(int dfd, const char __user *pathname,
++			   const struct fsinfo_params __user *params, size_t params_size,
++			   void __user *result_buffer, size_t result_buf_size);
+ 
+ /*
+  * Architecture-specific system calls
+diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
+index 2056318988f77..3a2e44f770f8e 100644
+--- a/include/uapi/asm-generic/unistd.h
++++ b/include/uapi/asm-generic/unistd.h
+@@ -859,9 +859,11 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd)
+ __SYSCALL(__NR_faccessat2, sys_faccessat2)
+ #define __NR_process_madvise 440
+ __SYSCALL(__NR_process_madvise, sys_process_madvise)
++#define __NR_fsinfo 441
++__SYSCALL(__NR_fsinfo, sys_fsinfo)
+ 
+ #undef __NR_syscalls
+-#define __NR_syscalls 441
++#define __NR_syscalls 443
+ 
+ /*
+  * 32 bit systems traditionally used different
+diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
+new file mode 100644
+index 0000000000000..65892239ba86c
+--- /dev/null
++++ b/include/uapi/linux/fsinfo.h
+@@ -0,0 +1,189 @@
++/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
++/* fsinfo() definitions.
++ *
++ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
++ * Written by David Howells (dhowells@redhat.com)
++ */
++#ifndef _UAPI_LINUX_FSINFO_H
++#define _UAPI_LINUX_FSINFO_H
++
++#include <linux/types.h>
++#include <linux/socket.h>
++#include <linux/openat2.h>
++
++/*
++ * The filesystem attributes that can be requested.  Note that some attributes
++ * may have multiple instances which can be switched in the parameter block.
++ */
++#define FSINFO_ATTR_STATFS		0x00	/* statfs()-style state */
++#define FSINFO_ATTR_IDS			0x01	/* Filesystem IDs */
++#define FSINFO_ATTR_LIMITS		0x02	/* Filesystem limits */
++#define FSINFO_ATTR_SUPPORTS		0x03	/* What's supported in statx, iocflags, ... */
++#define FSINFO_ATTR_TIMESTAMP_INFO	0x04	/* Inode timestamp info */
++#define FSINFO_ATTR_VOLUME_ID		0x05	/* Volume ID (string) */
++#define FSINFO_ATTR_VOLUME_UUID		0x06	/* Volume UUID (LE uuid) */
++#define FSINFO_ATTR_VOLUME_NAME		0x07	/* Volume name (string) */
++
++#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO 0x100	/* Information about attr N (for path) */
++#define FSINFO_ATTR_FSINFO_ATTRIBUTES	0x101	/* List of supported attrs (for path) */
++
++/*
++ * Optional fsinfo() parameter structure.
++ *
++ * If this is not given, it is assumed that fsinfo_attr_statfs instance 0,0 is
++ * desired.
++ */
++struct fsinfo_params {
++	__u64	resolve_flags;	/* RESOLVE_* flags */
++	__u32	at_flags;	/* AT_* flags */
++	__u32	flags;		/* Flags controlling fsinfo() specifically */
++#define FSINFO_FLAGS_QUERY_MASK	0x0007 /* What object should fsinfo() query? */
++#define FSINFO_FLAGS_QUERY_PATH	0x0000 /* - path, specified by dirfd,pathname,AT_EMPTY_PATH */
++#define FSINFO_FLAGS_QUERY_FD	0x0001 /* - fd specified by dirfd */
++	__u32	request;	/* ID of requested attribute */
++	__u32	Nth;		/* Instance of it (some may have multiple) */
++	__u32	Mth;		/* Subinstance of Nth instance */
++};
++
++enum fsinfo_value_type {
++	FSINFO_TYPE_VSTRUCT	= 0,	/* Version-lengthed struct (up to 4096 bytes) */
++	FSINFO_TYPE_STRING	= 1,	/* NUL-term var-length string (up to 4095 chars) */
++	FSINFO_TYPE_OPAQUE	= 2,	/* Opaque blob (unlimited size) */
++	FSINFO_TYPE_LIST	= 3,	/* List of ints/structs (unlimited size) */
++};
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO).
++ *
++ * This gives information about the attributes supported by fsinfo for the
++ * given path.
++ */
++struct fsinfo_attribute_info {
++	unsigned int		attr_id;	/* The ID of the attribute */
++	enum fsinfo_value_type	type;		/* The type of the attribute's value(s) */
++	unsigned int		flags;
++#define FSINFO_FLAGS_N		0x01		/* - Attr has a set of values */
++#define FSINFO_FLAGS_NM		0x02		/* - Attr has a set of sets of values */
++	unsigned int		size;		/* - Value size (FSINFO_STRUCT/FSINFO_LIST) */
++};
++
++#define FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO__STRUCT struct fsinfo_attribute_info
++#define FSINFO_ATTR_FSINFO_ATTRIBUTES__STRUCT __u32
++
++struct fsinfo_u128 {
++#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
++	__u64	hi;
++	__u64	lo;
++#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
++	__u64	lo;
++	__u64	hi;
++#endif
++};
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_STATFS).
++ * - This gives extended filesystem information.
++ */
++struct fsinfo_statfs {
++	struct fsinfo_u128 f_blocks;	/* Total number of blocks in fs */
++	struct fsinfo_u128 f_bfree;	/* Total number of free blocks */
++	struct fsinfo_u128 f_bavail;	/* Number of free blocks available to ordinary user */
++	struct fsinfo_u128 f_files;	/* Total number of file nodes in fs */
++	struct fsinfo_u128 f_ffree;	/* Number of free file nodes */
++	struct fsinfo_u128 f_favail;	/* Number of file nodes available to ordinary user */
++	__u64	f_bsize;		/* Optimal block size */
++	__u64	f_frsize;		/* Fragment size */
++};
++
++#define FSINFO_ATTR_STATFS__STRUCT struct fsinfo_statfs
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_IDS).
++ *
++ * List of basic identifiers as is normally found in statfs().
++ */
++struct fsinfo_ids {
++	char	f_fs_name[15 + 1];	/* Filesystem name */
++	__u64	f_fsid;			/* Short 64-bit Filesystem ID (as statfs) */
++	__u64	f_sb_id;		/* Internal superblock ID for sbnotify()/mntnotify() */
++	__u32	f_fstype;		/* Filesystem type from linux/magic.h [uncond] */
++	__u32	f_dev_major;		/* As st_dev_* from struct statx [uncond] */
++	__u32	f_dev_minor;
++	__u32	__padding[1];
++};
++
++#define FSINFO_ATTR_IDS__STRUCT struct fsinfo_ids
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_LIMITS).
++ *
++ * List of supported filesystem limits.
++ */
++struct fsinfo_limits {
++	struct fsinfo_u128 max_file_size;	/* Maximum file size */
++	struct fsinfo_u128 max_ino;		/* Maximum inode number */
++	__u64	max_uid;			/* Maximum UID supported */
++	__u64	max_gid;			/* Maximum GID supported */
++	__u64	max_projid;			/* Maximum project ID supported */
++	__u64	max_hard_links;			/* Maximum number of hard links on a file */
++	__u64	max_xattr_body_len;		/* Maximum xattr content length */
++	__u32	max_xattr_name_len;		/* Maximum xattr name length */
++	__u32	max_filename_len;		/* Maximum filename length */
++	__u32	max_symlink_len;		/* Maximum symlink content length */
++	__u32	max_dev_major;			/* Maximum device major representable */
++	__u32	max_dev_minor;			/* Maximum device minor representable */
++	__u32	__padding[1];
++};
++
++#define FSINFO_ATTR_LIMITS__STRUCT struct fsinfo_limits
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_SUPPORTS).
++ *
++ * What's supported in various masks, such as statx() attribute and mask bits
++ * and IOC flags.
++ */
++struct fsinfo_supports {
++	__u64	stx_attributes;		/* What statx::stx_attributes are supported */
++	__u32	stx_mask;		/* What statx::stx_mask bits are supported */
++	__u32	fs_ioc_getflags;	/* What FS_IOC_GETFLAGS may return */
++	__u32	fs_ioc_setflags_set;	/* What FS_IOC_SETFLAGS may set */
++	__u32	fs_ioc_setflags_clear;	/* What FS_IOC_SETFLAGS may clear */
++	__u32	fs_ioc_fsgetxattr_xflags; /* What FS_IOC_FSGETXATTR[A] may return in fsx_xflags */
++	__u32	fs_ioc_fssetxattr_xflags_set; /* What FS_IOC_FSSETXATTR may set in fsx_xflags */
++	__u32	fs_ioc_fssetxattr_xflags_clear; /* What FS_IOC_FSSETXATTR may set in fsx_xflags */
++	__u32	win_file_attrs;		/* What DOS/Windows FILE_* attributes are supported */
++};
++
++#define FSINFO_ATTR_SUPPORTS__STRUCT struct fsinfo_supports
++
++struct fsinfo_timestamp_one {
++	__s64	minimum;	/* Minimum timestamp value in seconds */
++	__s64	maximum;	/* Maximum timestamp value in seconds */
++	__u16	gran_mantissa;	/* Granularity(secs) = mant * 10^exp */
++	__s8	gran_exponent;
++	__u8	__padding[5];
++};
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_TIMESTAMP_INFO).
++ */
++struct fsinfo_timestamp_info {
++	struct fsinfo_timestamp_one	atime;	/* Access time */
++	struct fsinfo_timestamp_one	mtime;	/* Modification time */
++	struct fsinfo_timestamp_one	ctime;	/* Change time */
++	struct fsinfo_timestamp_one	btime;	/* Birth/creation time */
++};
++
++#define FSINFO_ATTR_TIMESTAMP_INFO__STRUCT struct fsinfo_timestamp_info
++
++/*
++ * Information struct for fsinfo(FSINFO_ATTR_VOLUME_UUID).
++ */
++struct fsinfo_volume_uuid {
++	__u8	uuid[16];
++};
++
++#define FSINFO_ATTR_VOLUME_UUID__STRUCT struct fsinfo_volume_uuid
++
++#endif /* _UAPI_LINUX_FSINFO_H */
+diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
+index f27ac94d5fa72..3cf167e82606f 100644
+--- a/kernel/sys_ni.c
++++ b/kernel/sys_ni.c
+@@ -51,6 +51,7 @@ COND_SYSCALL_COMPAT(io_pgetevents);
+ COND_SYSCALL(io_uring_setup);
+ COND_SYSCALL(io_uring_enter);
+ COND_SYSCALL(io_uring_register);
++COND_SYSCALL(fsinfo);
+ 
+ /* fs/xattr.c */
+ 
+diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile
+index 6377a678134ac..8efb67c45ceaa 100644
+--- a/samples/vfs/Makefile
++++ b/samples/vfs/Makefile
+@@ -1,4 +1,4 @@
+ # SPDX-License-Identifier: GPL-2.0-only
+-userprogs-always-y += test-fsmount test-statx
++userprogs-always-y += test-fsinfo test-fsmount test-statx
+ 
+ userccflags += -I usr/include
+diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
+new file mode 100644
+index 0000000000000..934b25399ffed
+--- /dev/null
++++ b/samples/vfs/test-fsinfo.c
+@@ -0,0 +1,646 @@
++// SPDX-License-Identifier: GPL-2.0-or-later
++/* Test the fsinfo() system call
++ *
++ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
++ * Written by David Howells (dhowells@redhat.com)
++ */
++
++#define _GNU_SOURCE
++#define _ATFILE_SOURCE
++#include <stdbool.h>
++#include <stdio.h>
++#include <stdlib.h>
++#include <stdint.h>
++#include <string.h>
++#include <unistd.h>
++#include <ctype.h>
++#include <errno.h>
++#include <time.h>
++#include <math.h>
++#include <fcntl.h>
++#include <sys/syscall.h>
++#include <linux/fsinfo.h>
++#include <linux/socket.h>
++#include <sys/stat.h>
++#include <arpa/inet.h>
++
++#ifndef __NR_fsinfo
++#define __NR_fsinfo -1
++#endif
++
++static bool debug = 0;
++static bool list_last;
++
++static __attribute__((unused))
++ssize_t fsinfo(int dfd, const char *filename,
++	       struct fsinfo_params *params, size_t params_size,
++	       void *result_buffer, size_t result_buf_size)
++{
++	return syscall(__NR_fsinfo, dfd, filename,
++		       params, params_size,
++		       result_buffer, result_buf_size);
++}
++
++struct fsinfo_attribute {
++	unsigned int		attr_id;
++	enum fsinfo_value_type	type;
++	unsigned int		size;
++	const char		*name;
++	void (*dump)(void *reply, unsigned int size);
++};
++
++static const struct fsinfo_attribute fsinfo_attributes[];
++
++static ssize_t get_fsinfo(const char *, const char *, struct fsinfo_params *, void **);
++
++static void dump_hex(FILE *f, unsigned char *data, int from, int to)
++{
++	unsigned offset, col = 0;
++	bool print_offset = true;
++
++	for (offset = from; offset < to; offset++) {
++		if (print_offset) {
++			fprintf(f, "%04x: ", offset);
++			print_offset = 0;
++		}
++		fprintf(f, "%02x", data[offset]);
++		col++;
++		if ((col & 3) == 0) {
++			if ((col & 15) == 0) {
++				fprintf(f, "\n");
++				print_offset = 1;
++			} else {
++				fprintf(f, " ");
++			}
++		}
++	}
++
++	if (!print_offset)
++		fprintf(f, "\n");
++}
++
++static void dump_attribute_info(void *reply, unsigned int size)
++{
++	struct fsinfo_attribute_info *attr_info = reply;
++	const struct fsinfo_attribute *attr;
++	char type[32], val_size[32];
++
++	switch (attr_info->type) {
++	case FSINFO_TYPE_VSTRUCT:	strcpy(type, "V-STRUCT");	break;
++	case FSINFO_TYPE_STRING:	strcpy(type, "STRING");		break;
++	case FSINFO_TYPE_OPAQUE:	strcpy(type, "OPAQUE");		break;
++	case FSINFO_TYPE_LIST:		strcpy(type, "LIST");		break;
++	default:
++		sprintf(type, "type-%x", attr_info->type);
++		break;
++	}
++
++	if (attr_info->flags & FSINFO_FLAGS_N)
++		strcat(type, " x N");
++	else if (attr_info->flags & FSINFO_FLAGS_NM)
++		strcat(type, " x NM");
++
++	for (attr = fsinfo_attributes; attr->name; attr++)
++		if (attr->attr_id == attr_info->attr_id)
++			break;
++
++	if (attr_info->size)
++		sprintf(val_size, "%u", attr_info->size);
++	else
++		strcpy(val_size, "-");
++
++	printf("%8x %-12s %08x %5s %s\n",
++	       attr_info->attr_id,
++	       type,
++	       attr_info->flags,
++	       val_size,
++	       attr->name ? attr->name : "");
++}
++
++static void dump_fsinfo_generic_statfs(void *reply, unsigned int size)
++{
++	struct fsinfo_statfs *f = reply;
++
++	printf("\n");
++	printf("\tblocks       : n=%llu fr=%llu av=%llu\n",
++	       (unsigned long long)f->f_blocks.lo,
++	       (unsigned long long)f->f_bfree.lo,
++	       (unsigned long long)f->f_bavail.lo);
++
++	printf("\tfiles        : n=%llu fr=%llu av=%llu\n",
++	       (unsigned long long)f->f_files.lo,
++	       (unsigned long long)f->f_ffree.lo,
++	       (unsigned long long)f->f_favail.lo);
++	printf("\tbsize        : %llu\n",
++	       (unsigned long long)f->f_bsize);
++	printf("\tfrsize       : %llu\n",
++	       (unsigned long long)f->f_frsize);
++}
++
++static void dump_fsinfo_generic_ids(void *reply, unsigned int size)
++{
++	struct fsinfo_ids *f = reply;
++
++	printf("\n");
++	printf("\tdev          : %02x:%02x\n", f->f_dev_major, f->f_dev_minor);
++	printf("\tfs           : type=%x name=%s\n", f->f_fstype, f->f_fs_name);
++	printf("\tfsid         : %llx\n", (unsigned long long)f->f_fsid);
++	printf("\tsbid         : %llx\n", (unsigned long long)f->f_sb_id);
++}
++
++static void dump_fsinfo_generic_limits(void *reply, unsigned int size)
++{
++	struct fsinfo_limits *f = reply;
++
++	printf("\n");
++	printf("\tmax file size: %llx%016llx\n",
++	       (unsigned long long)f->max_file_size.hi,
++	       (unsigned long long)f->max_file_size.lo);
++	printf("\tmax ino      : %llx%016llx\n",
++	       (unsigned long long)f->max_ino.hi,
++	       (unsigned long long)f->max_ino.lo);
++	printf("\tmax ids      : u=%llx g=%llx p=%llx\n",
++	       (unsigned long long)f->max_uid,
++	       (unsigned long long)f->max_gid,
++	       (unsigned long long)f->max_projid);
++	printf("\tmax dev      : maj=%x min=%x\n",
++	       f->max_dev_major, f->max_dev_minor);
++	printf("\tmax links    : %llx\n",
++	       (unsigned long long)f->max_hard_links);
++	printf("\tmax xattr    : n=%x b=%llx\n",
++	       f->max_xattr_name_len,
++	       (unsigned long long)f->max_xattr_body_len);
++	printf("\tmax len      : file=%x sym=%x\n",
++	       f->max_filename_len, f->max_symlink_len);
++}
++
++static void dump_fsinfo_generic_supports(void *reply, unsigned int size)
++{
++	struct fsinfo_supports *f = reply;
++
++	printf("\n");
++	printf("\tstx_attr     : %llx\n", (unsigned long long)f->stx_attributes);
++	printf("\tstx_mask     : %x\n", f->stx_mask);
++	printf("\tfs_ioc_*flags: get=%x set=%x clr=%x\n",
++	       f->fs_ioc_getflags, f->fs_ioc_setflags_set, f->fs_ioc_setflags_clear);
++	printf("\tfs_ioc_*xattr: fsx_xflags: get=%x set=%x clr=%x\n",
++	       f->fs_ioc_fsgetxattr_xflags,
++	       f->fs_ioc_fssetxattr_xflags_set,
++	       f->fs_ioc_fssetxattr_xflags_clear);
++	printf("\twin_fattrs   : %x\n", f->win_file_attrs);
++}
++
++static void print_time(struct fsinfo_timestamp_one *t, char stamp)
++{
++	printf("\t%ctime       : gran=%uE%d range=%llx-%llx\n",
++	       stamp,
++	       t->gran_mantissa, t->gran_exponent,
++	       (long long)t->minimum, (long long)t->maximum);
++}
++
++static void dump_fsinfo_generic_timestamp_info(void *reply, unsigned int size)
++{
++	struct fsinfo_timestamp_info *f = reply;
++
++	printf("\n");
++	print_time(&f->atime, 'a');
++	print_time(&f->mtime, 'm');
++	print_time(&f->ctime, 'c');
++	print_time(&f->btime, 'b');
++}
++
++static void dump_fsinfo_generic_volume_uuid(void *reply, unsigned int size)
++{
++	struct fsinfo_volume_uuid *f = reply;
++
++	printf("%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x"
++	       "-%02x%02x%02x%02x%02x%02x\n",
++	       f->uuid[ 0], f->uuid[ 1],
++	       f->uuid[ 2], f->uuid[ 3],
++	       f->uuid[ 4], f->uuid[ 5],
++	       f->uuid[ 6], f->uuid[ 7],
++	       f->uuid[ 8], f->uuid[ 9],
++	       f->uuid[10], f->uuid[11],
++	       f->uuid[12], f->uuid[13],
++	       f->uuid[14], f->uuid[15]);
++}
++
++static void dump_string(void *reply, unsigned int size)
++{
++	char *s = reply, *p;
++	bool nl = false, last_nl = false;
++
++	p = s;
++	if (size >= 4096) {
++		size = 4096;
++		p[4092] = '.';
++		p[4093] = '.';
++		p[4094] = '.';
++		p[4095] = 0;
++	} else {
++		p[size] = 0;
++	}
++
++	for (p = s; *p; p++) {
++		if (*p == '\n') {
++			last_nl = nl = true;
++			continue;
++		}
++		last_nl = false;
++		if (!isprint(*p) && *p != '\t')
++			*p = '?';
++	}
++
++	if (nl)
++		putchar('\n');
++	printf("%s", s);
++	if (!last_nl)
++		putchar('\n');
++}
++
++#define dump_fsinfo_meta_attribute_info		(void *)0x123
++#define dump_fsinfo_meta_attributes		(void *)0x123
++
++/*
++ *
++ */
++#define __FSINFO(A, T, S, G, F, N)					\
++	{ .attr_id = A, .type = T, .size = S, .name = N, .dump = dump_##G }
++
++#define _FSINFO(A,T,S,G,N)	__FSINFO(A, T, S, G, 0, N)
++#define _FSINFO_N(A,T,S,G,N)	__FSINFO(A, T, S, G, FSINFO_FLAGS_N, N)
++#define _FSINFO_NM(A,T,S,G,N)	__FSINFO(A, T, S, G, FSINFO_FLAGS_NM, N)
++
++#define _FSINFO_VSTRUCT(A,S,G,N)    _FSINFO   (A, FSINFO_TYPE_VSTRUCT, sizeof(S), G, N)
++#define _FSINFO_VSTRUCT_N(A,S,G,N)  _FSINFO_N (A, FSINFO_TYPE_VSTRUCT, sizeof(S), G, N)
++#define _FSINFO_VSTRUCT_NM(A,S,G,N) _FSINFO_NM(A, FSINFO_TYPE_VSTRUCT, sizeof(S), G, N)
++
++#define FSINFO_VSTRUCT(A,G)	_FSINFO_VSTRUCT   (A, A##__STRUCT, G, #A)
++#define FSINFO_VSTRUCT_N(A,G)	_FSINFO_VSTRUCT_N (A, A##__STRUCT, G, #A)
++#define FSINFO_VSTRUCT_NM(A,G)	_FSINFO_VSTRUCT_NM(A, A##__STRUCT, G, #A)
++#define FSINFO_STRING(A,G)	_FSINFO   (A, FSINFO_TYPE_STRING, 0, G, #A)
++#define FSINFO_STRING_N(A,G)	_FSINFO_N (A, FSINFO_TYPE_STRING, 0, G, #A)
++#define FSINFO_STRING_NM(A,G)	_FSINFO_NM(A, FSINFO_TYPE_STRING, 0, G, #A)
++#define FSINFO_OPAQUE(A,G)	_FSINFO   (A, FSINFO_TYPE_OPAQUE, 0, G, #A)
++#define FSINFO_LIST(A,G)	_FSINFO   (A, FSINFO_TYPE_LIST, sizeof(A##__STRUCT), G, #A)
++#define FSINFO_LIST_N(A,G)	_FSINFO_N (A, FSINFO_TYPE_LIST, sizeof(A##__STRUCT), G, #A)
++
++static const struct fsinfo_attribute fsinfo_attributes[] = {
++	FSINFO_VSTRUCT	(FSINFO_ATTR_STATFS,		fsinfo_generic_statfs),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_IDS,		fsinfo_generic_ids),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_LIMITS,		fsinfo_generic_limits),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_SUPPORTS,		fsinfo_generic_supports),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_TIMESTAMP_INFO,	fsinfo_generic_timestamp_info),
++	FSINFO_STRING	(FSINFO_ATTR_VOLUME_ID,		string),
++	FSINFO_VSTRUCT	(FSINFO_ATTR_VOLUME_UUID,	fsinfo_generic_volume_uuid),
++	FSINFO_STRING	(FSINFO_ATTR_VOLUME_NAME,	string),
++	FSINFO_VSTRUCT_N(FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO, fsinfo_meta_attribute_info),
++	FSINFO_LIST	(FSINFO_ATTR_FSINFO_ATTRIBUTES,	fsinfo_meta_attributes),
++	{}
++};
++
++static __attribute__((noreturn))
++void bad_value(const char *what,
++	       struct fsinfo_params *params,
++	       const struct fsinfo_attribute *attr,
++	       const struct fsinfo_attribute_info *attr_info,
++	       void *reply, unsigned int size)
++{
++	printf("\n");
++	fprintf(stderr, "%s %s{%u}{%u} t=%x f=%x s=%x\n",
++		what, attr->name, params->Nth, params->Mth,
++		attr_info->type, attr_info->flags, attr_info->size);
++	fprintf(stderr, "size=%u\n", size);
++	dump_hex(stderr, reply, 0, size);
++	exit(1);
++}
++
++static void dump_value(unsigned int attr_id,
++		       const struct fsinfo_attribute *attr,
++		       const struct fsinfo_attribute_info *attr_info,
++		       void *reply, unsigned int size)
++{
++	if (!attr || !attr->dump) {
++		printf("<no dumper>\n");
++		return;
++	}
++
++	if (attr->type == FSINFO_TYPE_VSTRUCT && size < attr->size) {
++		printf("<short data %u/%u>\n", size, attr->size);
++		return;
++	}
++
++	attr->dump(reply, size);
++}
++
++static void dump_list(unsigned int attr_id,
++		      const struct fsinfo_attribute *attr,
++		      const struct fsinfo_attribute_info *attr_info,
++		      void *reply, unsigned int size)
++{
++	size_t elem_size = attr_info->size;
++	unsigned int ix = 0;
++
++	printf("\n");
++	if (!attr || !attr->dump) {
++		printf("<no dumper>\n");
++		return;
++	}
++
++	if (attr->type == FSINFO_TYPE_VSTRUCT && size < attr->size) {
++		printf("<short data %u/%u>\n", size, attr->size);
++		return;
++	}
++
++	list_last = false;
++	while (size >= elem_size) {
++		printf("\t[%02x] ", ix);
++		if (size == elem_size)
++			list_last = true;
++		attr->dump(reply, size);
++		reply += elem_size;
++		size -= elem_size;
++		ix++;
++	}
++}
++
++/*
++ * Call fsinfo, expanding the buffer as necessary.
++ */
++static ssize_t get_fsinfo(const char *file, const char *name,
++			  struct fsinfo_params *params, void **_r)
++{
++	ssize_t ret;
++	size_t buf_size = 4096;
++	void *r;
++
++	for (;;) {
++		r = malloc(buf_size);
++		if (!r) {
++			perror("malloc");
++			exit(1);
++		}
++		memset(r, 0xbd, buf_size);
++
++		errno = 0;
++		ret = fsinfo(AT_FDCWD, file, params, sizeof(*params), r, buf_size - 1);
++		if (ret == -1)
++			goto error;
++
++		if (ret <= buf_size - 1)
++			break;
++		buf_size = (ret + 4096 - 1) & ~(4096 - 1);
++	}
++
++	if (debug)
++		printf("fsinfo(%s,%s,%u,%u) = %zd\n",
++		       file, name, params->Nth, params->Mth, ret);
++
++	((char *)r)[ret] = 0;
++	*_r = r;
++	return ret;
++
++error:
++	*_r = NULL;
++	free(r);
++	if (debug)
++		printf("fsinfo(%s,%s,%u,%u) = %m\n",
++		       file, name, params->Nth, params->Mth);
++	return ret;
++}
++
++/*
++ * Try one subinstance of an attribute.
++ */
++static int try_one(const char *file, struct fsinfo_params *params,
++		   const struct fsinfo_attribute_info *attr_info, bool raw)
++{
++	const struct fsinfo_attribute *attr;
++	const char *name;
++	size_t size = 4096;
++	char namebuf[32];
++	void *r;
++
++	for (attr = fsinfo_attributes; attr->name; attr++) {
++		if (attr->attr_id == params->request) {
++			name = attr->name;
++			if (strncmp(name, "fsinfo_generic_", 15) == 0)
++				name += 15;
++			goto found;
++		}
++	}
++
++	sprintf(namebuf, "<unknown-%x>", params->request);
++	name = namebuf;
++	attr = NULL;
++
++found:
++	size = get_fsinfo(file, name, params, &r);
++
++	if (size == -1) {
++		if (errno == ENODATA) {
++			if (!(attr_info->flags & (FSINFO_FLAGS_N | FSINFO_FLAGS_NM)) &&
++			    params->Nth == 0 && params->Mth == 0)
++				bad_value("Unexpected ENODATA",
++					  params, attr, attr_info, r, size);
++			free(r);
++			return (params->Mth == 0) ? 2 : 1;
++		}
++		if (errno == EOPNOTSUPP) {
++			if (params->Nth > 0 || params->Mth > 0)
++				bad_value("Should return ENODATA",
++					  params, attr, attr_info, r, size);
++			//printf("\e[33m%s\e[m: <not supported>\n",
++			//       fsinfo_attr_names[attr]);
++			free(r);
++			return 2;
++		}
++		perror(file);
++		exit(1);
++	}
++
++	if (raw) {
++		if (size > 4096)
++			size = 4096;
++		dump_hex(stdout, r, 0, size);
++		free(r);
++		return 0;
++	}
++
++	switch (attr_info->flags & (FSINFO_FLAGS_N | FSINFO_FLAGS_NM)) {
++	case 0:
++		printf("\e[33m%s\e[m: ", name);
++		break;
++	case FSINFO_FLAGS_N:
++		printf("\e[33m%s{%u}\e[m: ", name, params->Nth);
++		break;
++	case FSINFO_FLAGS_NM:
++		printf("\e[33m%s{%u,%u}\e[m: ", name, params->Nth, params->Mth);
++		break;
++	}
++
++	switch (attr_info->type) {
++	case FSINFO_TYPE_STRING:
++		if (size == 0 || ((char *)r)[size - 1] != 0)
++			bad_value("Unterminated string",
++				  params, attr, attr_info, r, size);
++	case FSINFO_TYPE_VSTRUCT:
++	case FSINFO_TYPE_OPAQUE:
++		dump_value(params->request, attr, attr_info, r, size);
++		free(r);
++		return 0;
++
++	case FSINFO_TYPE_LIST:
++		dump_list(params->request, attr, attr_info, r, size);
++		free(r);
++		return 0;
++
++	default:
++		bad_value("Fishy type", params, attr, attr_info, r, size);
++	}
++}
++
++static int cmp_u32(const void *a, const void *b)
++{
++	return *(const int *)a - *(const int *)b;
++}
++
++/*
++ *
++ */
++int main(int argc, char **argv)
++{
++	struct fsinfo_attribute_info attr_info;
++	struct fsinfo_params params = {
++		.at_flags	= AT_SYMLINK_NOFOLLOW,
++		.flags		= FSINFO_FLAGS_QUERY_PATH,
++	};
++	unsigned int *attrs, ret, nr, i;
++	bool meta = false;
++	int raw = 0, opt, Nth, Mth;
++
++	while ((opt = getopt(argc, argv, "Madlr"))) {
++		switch (opt) {
++		case 'M':
++			meta = true;
++			continue;
++		case 'a':
++			params.at_flags |= AT_NO_AUTOMOUNT;
++			params.flags = FSINFO_FLAGS_QUERY_PATH;
++			continue;
++		case 'd':
++			debug = true;
++			continue;
++		case 'l':
++			params.at_flags &= ~AT_SYMLINK_NOFOLLOW;
++			params.flags = FSINFO_FLAGS_QUERY_PATH;
++			continue;
++		case 'r':
++			raw = 1;
++			continue;
++		}
++		break;
++	}
++
++	argc -= optind;
++	argv += optind;
++
++	if (argc != 1) {
++		printf("Format: test-fsinfo [-Madlr] <path>\n");
++		exit(2);
++	}
++
++	/* Retrieve a list of supported attribute IDs */
++	params.request = FSINFO_ATTR_FSINFO_ATTRIBUTES;
++	params.Nth = 0;
++	params.Mth = 0;
++	ret = get_fsinfo(argv[0], "attributes", &params, (void **)&attrs);
++	if (ret == -1) {
++		fprintf(stderr, "Unable to get attribute list: %m\n");
++		exit(1);
++	}
++
++	if (ret % sizeof(attrs[0])) {
++		fprintf(stderr, "Bad length of attribute list (0x%x)\n", ret);
++		exit(2);
++	}
++
++	nr = ret / sizeof(attrs[0]);
++	qsort(attrs, nr, sizeof(attrs[0]), cmp_u32);
++
++	if (meta) {
++		printf("ATTR ID  TYPE         FLAGS    SIZE  NAME\n");
++		printf("======== ============ ======== ===== =========\n");
++		for (i = 0; i < nr; i++) {
++			params.request = FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO;
++			params.Nth = attrs[i];
++			params.Mth = 0;
++			ret = fsinfo(AT_FDCWD, argv[0],
++				     &params, sizeof(params),
++				     &attr_info, sizeof(attr_info));
++			if (ret == -1) {
++				fprintf(stderr, "Can't get info for attribute %x: %m\n", attrs[i]);
++				exit(1);
++			}
++
++			dump_attribute_info(&attr_info, ret);
++		}
++		exit(0);
++	}
++
++	for (i = 0; i < nr; i++) {
++		params.request = FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO;
++		params.Nth = attrs[i];
++		params.Mth = 0;
++		ret = fsinfo(AT_FDCWD, argv[0],
++			     &params, sizeof(params),
++			     &attr_info, sizeof(attr_info));
++		if (ret == -1) {
++			fprintf(stderr, "Can't get info for attribute %x: %m\n", attrs[i]);
++			exit(1);
++		}
++
++		if (attrs[i] == FSINFO_ATTR_FSINFO_ATTRIBUTE_INFO ||
++		    attrs[i] == FSINFO_ATTR_FSINFO_ATTRIBUTES)
++			continue;
++
++		if (attrs[i] != attr_info.attr_id) {
++			fprintf(stderr, "ID for %03x returned %03x\n",
++				attrs[i], attr_info.attr_id);
++			break;
++		}
++		Nth = 0;
++		do {
++			Mth = 0;
++			do {
++				params.request = attrs[i];
++				params.Nth = Nth;
++				params.Mth = Mth;
++
++				switch (try_one(argv[0], &params, &attr_info, raw)) {
++				case 0:
++					continue;
++				case 1:
++					goto done_M;
++				case 2:
++					goto done_N;
++				}
++			} while (++Mth < 100);
++
++		done_M:
++			if (Mth >= 100) {
++				fprintf(stderr, "Fishy: Mth %x[%u][%u]\n", attrs[i], Nth, Mth);
++				break;
++			}
++
++		} while (++Nth < 100);
++
++	done_N:
++		if (Nth >= 100) {
++			fprintf(stderr, "Fishy: Nth %x[%u]\n", attrs[i], Nth);
++			break;
++		}
++	}
++
++	return 0;
++}
+-- 
+2.25.1
+