diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index b6cf8403da35..984abd1ac058 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -479,3 +479,4 @@
 548	common	pidfd_getfd			sys_pidfd_getfd
 549	common	faccessat2			sys_faccessat2
 550	common	watch_mount			sys_watch_mount
+551	common	fsinfo				sys_fsinfo
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 27cc1f53f4a0..bd791f91f5bb 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -453,3 +453,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 4f9cf98cdf0f..bd78eb2c487a 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -887,6 +887,8 @@ __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd)
 __SYSCALL(__NR_faccessat2, sys_faccessat2)
 #define __NR_watch_mount 440
 __SYSCALL(__NR_watch_mount, sys_watch_mount)
+#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 fc6d87903781..09d144487b7d 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -360,3 +360,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index c671aa0e4d25..1bdc26af3c54 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -439,3 +439,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 65cc53f129ef..fb8543122904 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -445,3 +445,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 7f034a239930..b8362bd6bd4a 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -378,3 +378,4 @@
 438	n32	pidfd_getfd			sys_pidfd_getfd
 439	n32	faccessat2			sys_faccessat2
 440	n32	watch_mount			sys_watch_mount
+441	n32	fsinfo				sys_fsinfo
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index d39b90de3642..60ca4091d378 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -354,3 +354,4 @@
 438	n64	pidfd_getfd			sys_pidfd_getfd
 439	n64	faccessat2			sys_faccessat2
 440	n64	watch_mount			sys_watch_mount
+441	n64	fsinfo				sys_fsinfo
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 09f426cb45b1..07aea9379ca0 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -427,3 +427,4 @@
 438	o32	pidfd_getfd			sys_pidfd_getfd
 439	o32	faccessat2			sys_faccessat2
 440	o32	watch_mount			sys_watch_mount
+441	o32	fsinfo				sys_fsinfo
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 52ff3454baa1..f8060767f11a 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 10b7ed3c7a1b..3036bf1336d2 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -529,3 +529,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 86f317bf52df..c0a111fdb3ce 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -442,3 +442,4 @@
 438  common	pidfd_getfd		sys_pidfd_getfd			sys_pidfd_getfd
 439  common	faccessat2		sys_faccessat2			sys_faccessat2
 440	common	watch_mount		sys_watch_mount			sys_watch_mount
+441	common	fsinfo			sys_fsinfo			sys_fsinfo
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 0bb0f0b372c7..03b55c32441f 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -442,3 +442,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 369ab65c1e9a..a0144db9fb8c 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -485,3 +485,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index e760ba92c58d..edf90a2be0b9 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -444,3 +444,4 @@
 438	i386	pidfd_getfd		sys_pidfd_getfd
 439	i386	faccessat2		sys_faccessat2
 440	i386	watch_mount		sys_watch_mount
+441	i386	fsinfo			sys_fsinfo
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 5b58621d4f75..ab0eda639d67 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -361,6 +361,7 @@
 438	common	pidfd_getfd		sys_pidfd_getfd
 439	common	faccessat2		sys_faccessat2
 440	common	watch_mount		sys_watch_mount
+441	common	fsinfo			sys_fsinfo
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 5b28ee39f70f..979013890caf 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -410,3 +410,4 @@
 438	common	pidfd_getfd			sys_pidfd_getfd
 439	common	faccessat2			sys_faccessat2
 440	common	watch_mount			sys_watch_mount
+441	common	fsinfo				sys_fsinfo
diff --git a/fs/Kconfig b/fs/Kconfig
index 1a55e56d5c54..df76451ab49a 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 dd0d87e2ef19..93a7f8047585 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -55,6 +55,7 @@ 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 000000000000..7d9c73e9cbde
--- /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 28a29356eace..3284f497de0a 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);
@@ -1963,6 +1964,9 @@ 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 000000000000..a811d69b02ff
--- /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 88d03fd627ab..e31ad49af4c3 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 __sysctl_args;
 struct sysinfo;
 struct timespec;
@@ -1007,6 +1008,9 @@ asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
 asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
 asmlinkage long sys_watch_mount(int dfd, const char __user *path,
 				unsigned int at_flags, int watch_fd, int watch_id);
+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 fcdca8c7d30a..801e6baebd50 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_watch_mount 440
 __SYSCALL(__NR_watch_mount, sys_watch_mount)
+#define __NR_fsinfo 442
+__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 000000000000..65892239ba86
--- /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 3e1c5c9d2efe..f72a9e4ddc9a 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 00b6824f9237..d63af5106fc2 100644
--- a/samples/vfs/Makefile
+++ b/samples/vfs/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-userprogs := test-fsmount test-statx
+userprogs := test-fsinfo test-fsmount test-statx
 always-y := $(userprogs)
 
 userccflags += -I usr/include
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
new file mode 100644
index 000000000000..934b25399ffe
--- /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;
+}
