[03/12] statx: Add a system call to make enhanced file info available
diff mbox

Message ID 20151120145457.18930.79678.stgit@warthog.procyon.org.uk
State New
Headers show

Commit Message

David Howells Nov. 20, 2015, 2:54 p.m. UTC
Add a system call to make extended file information available, including
file creation time, inode version and data version where available through
the underlying filesystem.



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Comments

Dave Chinner Nov. 24, 2015, 8:21 p.m. UTC | #1
On Fri, Nov 20, 2015 at 02:54:57PM +0000, David Howells wrote:
> The defined bits in st_ioc_flags are the usual FS_xxx_FL, plus some extra
> flags that might be supplied by the filesystem.  Note that Ext4 returns
> flags outside of {EXT4,FS}_FL_USER_VISIBLE in response to FS_IOC_GETFLAGS.
> Should {EXT4,FS}_FL_USER_VISIBLE be extended to cover them?  Or should the
> extra flags be suppressed?

Quite frankly, we should not expose flags owned by a filesystem like
this. Create a new set of flagsi that are exposed by the syscall,
and every filesystem is responsible for translating their internal
flag values to the syscall flag values....

> The defined bits in the st_information field give local system data on a
> file, how it is accessed, where it is and what it does:
> 
> 	STATX_INFO_ENCRYPTED		File is encrypted
> 	STATX_INFO_TEMPORARY		File is temporary (NTFS/CIFS/deleted)
> 	STATX_INFO_FABRICATED		File was made up by filesystem
> 	STATX_INFO_KERNEL_API		File is kernel API (eg: procfs/sysfs)
> 	STATX_INFO_REMOTE		File is remote
> 	STATX_INFO_OFFLINE		File is offline (CIFS)
> 	STATX_INFO_AUTOMOUNT		Dir is automount trigger
> 	STATX_INFO_AUTODIR		Dir provides unlisted automounts
> 	STATX_INFO_NONSYSTEM_OWNERSHIP	File has non-system ownership details
> 	STATX_INFO_REPARSE_POINT	File is reparse point (NTFS/CIFS)

	STATX_INFO_XATTR		File/dir has extended attrs

... just like these STATX_INFO flags are filesystem independent...

And, FWIW, I'd like to see more than one local filesystem supported
in the initial patchset (e.g. btrfs) and also have all their
inode/fs flags exposed so we don't end up encoding weird
ext4-specific feature quirks into the API.....

Cheers,

Dave.
Pavel Machek Dec. 4, 2015, 12:06 p.m. UTC | #2
Hi!

> ===============
> NEW SYSTEM CALL
> ===============
> 
> The new system call is:
> 
> 	int ret = statx(int dfd,
> 			const char *filename,
> 			unsigned int flags,
> 			unsigned int mask,
> 			struct statx *buffer);

Should this be called stat5, so that when new, even more improved stat
comes, it does not have to be called statxx?

> The dfd, filename and flags parameters indicate the file to query.  There
> is no equivalent of lstat() as that can be emulated with statx() by passing
> AT_SYMLINK_NOFOLLOW in flags.  There is also no equivalent of fstat() as
> that can be emulated by passing a NULL filename to statx() with the fd of
> interest in dfd.

Dunno. Of course you can multiplex everything.

But fstat() is really different operation to stat() -- tell me about
my file descriptor vs. tell me about this filename, and ptrace (and
some "security" solutions) might want to allow one but disallow the
second. I'd not group them together..

									Pavel
David Howells Dec. 21, 2015, 11:21 p.m. UTC | #3
Pavel Machek <pavel@ucw.cz> wrote:

> But fstat() is really different operation to stat() -- tell me about
> my file descriptor vs. tell me about this filename, and ptrace (and
> some "security" solutions) might want to allow one but disallow the
> second. I'd not group them together..

You can argue it either way.  I think Linus came down on the side of combining
them.

David
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Patch
diff mbox

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preferance proved to be for a new syscall
with an extended stat structure.

This has a number of uses:

 (1) Better support for the y2038 problem [Arnd Bergmann].

 (2) Creation time: The SMB protocol carries the creation time, which could
     be exported by Samba, which will in turn help CIFS make use of
     FS-Cache as that can be used for coherency data.

     This is also specified in NFSv4 as a recommended attribute and could
     be exported by NFSD [Steve French].

 (3) Lightweight stat: Ask for just those details of interest, and allow a
     netfs (such as NFS) to approximate anything not of interest, possibly
     without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
     Dilger].

 (4) Heavyweight stat: Force a netfs to go to the server, even if it thinks
     its cached attributes are up to date [Trond Myklebust].

 (5) Data version number: Could be used by userspace NFS servers [Aneesh
     Kumar].

     Can also be used to modify fill_post_wcc() in NFSD which retrieves
     i_version directly, but has just called vfs_getattr().  It could get
     it from the kstat struct if it used vfs_xgetattr() instead.

 (6) BSD stat compatibility: Including more fields from the BSD stat such
     as creation time (st_btime) and inode generation number (st_gen)
     [Jeremy Allison, Bernd Schubert].

 (7) Inode generation number: Useful for FUSE and userspace NFS servers
     [Bernd Schubert].  This was asked for but later deemed unnecessary
     with the open-by-handle capability available

 (8) Extra coherency data may be useful in making backups [Andreas Dilger].

 (9) Allow the filesystem to indicate what it can/cannot provide: A
     filesystem can now say it doesn't support a standard stat feature if
     that isn't available, so if, for instance, inode numbers or UIDs don't
     exist or are fabricated locally...

(10) Make the fields a consistent size on all arches and make them large.

(11) Store a 16-byte volume ID in the superblock that can be returned in
     struct xstat [Steve French].

(12) Include granularity fields in the time data to indicate the
     granularity of each of the times (NFSv4 time_delta) [Steve French].

(13) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
     Note that the Linux IOC flags are a mess and filesystems such as Ext4
     define flags that aren't in linux/fs.h, so translation in the kernel
     may be a necessity (or, possibly, we provide the filesystem type too).

(14) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
     Michael Kerrisk].

(15) Spare space, request flags and information flags are provided for
     future expansion.


===============
NEW SYSTEM CALL
===============

The new system call is:

	int ret = statx(int dfd,
			const char *filename,
			unsigned int flags,
			unsigned int mask,
			struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query.  There
is no equivalent of lstat() as that can be emulated with statx() by passing
AT_SYMLINK_NOFOLLOW in flags.  There is also no equivalent of fstat() as
that can be emulated by passing a NULL filename to statx() with the fd of
interest in dfd.

AT_FORCE_ATTR_SYNC can be set in flags.  This will require a network
filesystem to synchronise its attributes with the server.

AT_NO_ATTR_SYNC can be set in flags.  This will suppress synchronisation
with the server in a network filesystem.  The resulting values should be
considered approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().

buffer points to the destination for the main data.  This must be 256 bytes
in size.


======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

	struct statx {
		__u32	st_mask;
		__u32	st_information;
		__u16	st_mode;
		__u16	__spare0[1];
		__u32	st_nlink;
		__u32	st_uid;
		__u32	st_gid;
		__u32	st_blksize;
		__u32	__spare1[3];
		__u32	st_rdev_major;
		__u32	st_rdev_minor;
		__u32	st_dev_major;
		__u32	st_dev_minor;
		__s32	st_atime_ns;
		__s32	st_btime_ns;
		__s32	st_ctime_ns;
		__s32	st_mtime_ns;
		__s64	st_atime;
		__s64	st_btime;
		__s64	st_ctime;
		__s64	st_mtime;
		__u64	st_ino;
		__u64	st_size;
		__u64	st_blocks;
		__u64	st_version;
		__u64	st_ioc_flags;
		__u64	__spare1[14];
	};

where st_information is local system information about the file, st_btime
is the file creation time, st_version is the data version number
(i_version), st_ioc_flags holds the flags from FS_IOC_GETFLAGS, st_mask is
a bitmask indicating the data provided and __spares*[] are where as-yet
undefined fields can be placed.

Time fields are split into separate seconds and nanoseconds fields to make
packing easier and the granularities can be queried with the filesystem
info system call.  Note that times will be negative if before 1970; in such
a case, the nanosecond fields should also be negative if not zero.

The defined bits in request_mask and st_mask are:

	STATX_MODE		Want/got st_mode
	STATX_NLINK		Want/got st_nlink
	STATX_UID		Want/got st_uid
	STATX_GID		Want/got st_gid
	STATX_RDEV		Want/got st_rdev_*
	STATX_ATIME		Want/got st_atime
	STATX_MTIME		Want/got st_mtime
	STATX_CTIME		Want/got st_ctime
	STATX_INO		Want/got st_ino
	STATX_SIZE		Want/got st_size
	STATX_BLOCKS		Want/got st_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got st_btime
	STATX_VERSION		Want/got st_data_version
	STATX_IOC_FLAGS		Want/got FS_IOC_GETFLAGS
	STATX_ALL_STATS		[All currently available stuff]

The defined bits in st_ioc_flags are the usual FS_xxx_FL, plus some extra
flags that might be supplied by the filesystem.  Note that Ext4 returns
flags outside of {EXT4,FS}_FL_USER_VISIBLE in response to FS_IOC_GETFLAGS.
Should {EXT4,FS}_FL_USER_VISIBLE be extended to cover them?  Or should the
extra flags be suppressed?

The defined bits in the st_information field give local system data on a
file, how it is accessed, where it is and what it does:

	STATX_INFO_ENCRYPTED		File is encrypted
	STATX_INFO_TEMPORARY		File is temporary (NTFS/CIFS/deleted)
	STATX_INFO_FABRICATED		File was made up by filesystem
	STATX_INFO_KERNEL_API		File is kernel API (eg: procfs/sysfs)
	STATX_INFO_REMOTE		File is remote
	STATX_INFO_OFFLINE		File is offline (CIFS)
	STATX_INFO_AUTOMOUNT		Dir is automount trigger
	STATX_INFO_AUTODIR		Dir provides unlisted automounts
	STATX_INFO_NONSYSTEM_OWNERSHIP	File has non-system ownership details
	STATX_INFO_REPARSE_POINT	File is reparse point (NTFS/CIFS)

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.  I've tried not to provide overlap with
st_ioc_flags where something usable exists there.

The fields in struct statx come in a number of classes:

 (0) st_dev_*, st_information.

     These are local data and are always available.

 (1) st_nlinks, st_uid, st_gid, st_[amc]time*, st_ino, st_size, st_blocks,
     st_blksize.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in st_mask will be set to indicate their presence.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server, unless as
     a byproduct of updating something requested.

     If the values don't actually exist for the underlying object (such as
     UID or GID on a DOS file), then the bit won't be set in the st_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

 (2) st_mode.

     The part of this that identifies the file type will always be
     available, irrespective of the setting of STATX_MODE.  The access
     flags and sticky bit are as for class (1).

 (3) st_rdev_*.

     As for class (1), but these won't be returned if the file is not a
     blockdev or chardev.  The bit will be cleared if the value is not
     returned.

 (4) File creation time (st_btime*), data version (st_version), inode flags
     (st_ioc_flags).

     These will be returned if available whether the caller asked for them or
     not.  The corresponding bits in st_mask will be set or cleared as
     appropriate to indicate their presence.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server, unless
     as a byproduct of updating something requested.


=======
TESTING
=======

The following test program can be used to test the statx system call:

	samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the FABRICATED and AUTOMOUNT info flags are set.
The former because the directory is invented locally as we don't see the
underlying dir on the server, the latter because transiting this directory
will cause d_automount to be invoked by the VFS.

	[root@andromeda tmp]# ./samples/statx/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=4fef
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:1d           Inode: 2           Links: 110
	Access: (3777/drwxrwxrwx)  Uid: -2
	Gid: 4294967294
	Access: 2012-04-30 09:01:55.283819565+0100
	Modify: 2012-03-28 19:01:19.405465361+0100
	Change: 2012-03-28 19:01:19.405465361+0100
	Data version: ef51734f11e92a18h
	Information: 00000254 (-------- -------- ------a- -m-r-f--)

Secondly, the result of automounting on that directory.

	[root@andromeda tmp]# ./samples/statx/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=14fef
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:1e           Inode: 2           Links: 110
	Access: (3777/drwxrwxrwx)  Uid: -2
	Gid: 4294967294
	Access: 2012-04-30 09:01:55.283819565+0100
	Modify: 2012-03-28 19:01:19.405465361+0100
	Change: 2012-03-28 19:01:19.405465361+0100
	Data version: ef51734f11e92a18h
	Information: 00000210 (-------- -------- ------a- ---r----)

Signed-off-by: David Howells <dhowells@redhat.com>
---

 arch/x86/entry/syscalls/syscall_32.tbl |    1 
 arch/x86/entry/syscalls/syscall_64.tbl |    1 
 fs/exportfs/expfs.c                    |    4 
 fs/stat.c                              |  305 +++++++++++++++++++++++++++++---
 include/linux/fs.h                     |    5 -
 include/linux/stat.h                   |   14 +
 include/linux/syscalls.h               |    3 
 include/uapi/linux/fcntl.h             |    2 
 include/uapi/linux/stat.h              |  116 ++++++++++++
 samples/Makefile                       |    3 
 samples/statx/Makefile                 |   10 +
 samples/statx/test-statx.c             |  273 +++++++++++++++++++++++++++++
 12 files changed, 700 insertions(+), 37 deletions(-)
 create mode 100644 samples/statx/Makefile
 create mode 100644 samples/statx/test-statx.c

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 7663c455b9f6..6e570ee4241d 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -382,3 +382,4 @@ 
 373	i386	shutdown		sys_shutdown
 374	i386	userfaultfd		sys_userfaultfd
 375	i386	membarrier		sys_membarrier
+376	i386	statx			sys_statx
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 278842fdf1f6..cbfef23f8067 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -331,6 +331,7 @@ 
 322	64	execveat		stub_execveat
 323	common	userfaultfd		sys_userfaultfd
 324	common	membarrier		sys_membarrier
+325	common	statx			sys_statx
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 714cd37a6ba3..ef32ea41925e 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -295,7 +295,9 @@  static int get_name(const struct path *path, char *name, struct dentry *child)
 	 * filesystem supports 64-bit inode numbers.  So we need to
 	 * actually call ->getattr, not just read i_ino:
 	 */
-	error = vfs_getattr_nosec(&child_path, &stat);
+	stat.query_flags = 0;
+	stat.request_mask = STATX_BASIC_STATS;
+	error = vfs_xgetattr_nosec(&child_path, &stat);
 	if (error)
 		return error;
 	buffer.ino = stat.ino;
diff --git a/fs/stat.c b/fs/stat.c
index cccc1aab9a8b..573772cbe6f0 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -18,6 +18,15 @@ 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 
+/**
+ * generic_fillattr - Fill in the basic attributes from the inode struct
+ * @inode: Inode to use as the source
+ * @stat: Where to fill in the attributes
+ *
+ * Fill in the basic attributes in the kstat structure from data that's to be
+ * found on the VFS inode structure.  This is the default if no getattr inode
+ * operation is supplied.
+ */
 void generic_fillattr(struct inode *inode, struct kstat *stat)
 {
 	stat->dev = inode->i_sb->s_dev;
@@ -27,87 +36,198 @@  void generic_fillattr(struct inode *inode, struct kstat *stat)
 	stat->uid = inode->i_uid;
 	stat->gid = inode->i_gid;
 	stat->rdev = inode->i_rdev;
-	stat->size = i_size_read(inode);
-	stat->atime = inode->i_atime;
 	stat->mtime = inode->i_mtime;
 	stat->ctime = inode->i_ctime;
-	stat->blksize = (1 << inode->i_blkbits);
+	stat->size = i_size_read(inode);
 	stat->blocks = inode->i_blocks;
-}
+	stat->blksize = 1 << inode->i_blkbits;
 
+	stat->result_mask |= STATX_BASIC_STATS & ~STATX_RDEV;
+	if (IS_NOATIME(inode))
+		stat->result_mask &= ~STATX_ATIME;
+	else
+		stat->atime = inode->i_atime;
+
+	if (S_ISREG(stat->mode) && stat->nlink == 0)
+		stat->information |= STATX_INFO_TEMPORARY;
+	if (IS_AUTOMOUNT(inode))
+		stat->information |= STATX_INFO_AUTOMOUNT;
+
+	if (unlikely(S_ISBLK(stat->mode) || S_ISCHR(stat->mode)))
+		stat->result_mask |= STATX_RDEV;
+}
 EXPORT_SYMBOL(generic_fillattr);
 
 /**
- * vfs_getattr_nosec - getattr without security checks
+ * vfs_xgetattr_nosec - getattr without security checks
  * @path: file to get attributes from
  * @stat: structure to return attributes in
  *
  * Get attributes without calling security_inode_getattr.
  *
- * Currently the only caller other than vfs_getattr is internal to the
- * filehandle lookup code, which uses only the inode number and returns
- * no attributes to any user.  Any other code probably wants
- * vfs_getattr.
+ * Currently the only caller other than vfs_xgetattr is internal to the
+ * filehandle lookup code, which uses only the inode number and returns no
+ * attributes to any user.  Any other code probably wants vfs_xgetattr.
+ *
+ * The caller must set stat->request_mask to indicate what they want and
+ * stat->query_flags to indicate whether the server should be queried.
  */
-int vfs_getattr_nosec(struct path *path, struct kstat *stat)
+int vfs_xgetattr_nosec(struct path *path, struct kstat *stat)
 {
 	struct inode *inode = d_backing_inode(path->dentry);
 
+	stat->query_flags &= ~KSTAT_QUERY_FLAGS;
+	if ((stat->query_flags & AT_FORCE_ATTR_SYNC) &&
+	    (stat->query_flags & AT_NO_ATTR_SYNC))
+		return -EINVAL;
+
+	stat->result_mask = 0;
+	stat->information = 0;
+	stat->ioc_flags = 0;
 	if (inode->i_op->getattr)
 		return inode->i_op->getattr(path->mnt, path->dentry, stat);
 
 	generic_fillattr(inode, stat);
 	return 0;
 }
+EXPORT_SYMBOL(vfs_xgetattr_nosec);
 
-EXPORT_SYMBOL(vfs_getattr_nosec);
-
-int vfs_getattr(struct path *path, struct kstat *stat)
+/*
+ * vfs_xgetattr - Get the enhanced basic attributes of a file
+ * @path: The file of interest
+ * @stat: Where to return the statistics
+ *
+ * Ask the filesystem for a file's attributes.  The caller must have preset
+ * stat->request_mask and stat->query_flags to indicate what they want.
+ *
+ * If the file is remote, the filesystem can be forced to update the attributes
+ * from the backing store by passing AT_FORCE_ATTR_SYNC in query_flags or can
+ * suppress the update by passing AT_NO_ATTR_SYNC.
+ *
+ * Bits must have been set in stat->request_mask to indicate which attributes
+ * the caller wants retrieving.  Any such attribute not requested may be
+ * returned anyway, but the value may be approximate, and, if remote, may not
+ * have been synchronised with the server.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_xgetattr(struct path *path, struct kstat *stat)
 {
 	int retval;
 
 	retval = security_inode_getattr(path);
 	if (retval)
 		return retval;
-	return vfs_getattr_nosec(path, stat);
+	return vfs_xgetattr_nosec(path, stat);
 }
+EXPORT_SYMBOL(vfs_xgetattr);
 
+/**
+ * vfs_getattr - Get the basic attributes of a file
+ * @path: The file of interest
+ * @stat: Where to return the statistics
+ *
+ * Ask the filesystem for a file's attributes.  If remote, the filesystem isn't
+ * forced to update its files from the backing store.  Only the basic set of
+ * attributes will be retrieved; anyone wanting more must use vfs_xgetattr(),
+ * as must anyone who wants to force attributes to be sync'd with the server.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_getattr(struct path *path, struct kstat *stat)
+{
+	stat->query_flags = 0;
+	stat->request_mask = STATX_BASIC_STATS;
+	return vfs_xgetattr(path, stat);
+}
 EXPORT_SYMBOL(vfs_getattr);
 
-int vfs_fstat(unsigned int fd, struct kstat *stat)
+/**
+ * vfs_fstatx - Get the enhanced basic attributes by file descriptor
+ * @fd: The file descriptor referring to the file of interest
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_xgetattr().  The main difference is
+ * that it uses a file descriptor to determine the file location.
+ *
+ * The caller must have preset stat->query_flags, stat->request_mask and
+ * stat->auxinfo as for vfs_xgetattr().
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_fstatx(unsigned int fd, struct kstat *stat)
 {
 	struct fd f = fdget_raw(fd);
 	int error = -EBADF;
 
 	if (f.file) {
-		error = vfs_getattr(&f.file->f_path, stat);
+		error = vfs_xgetattr(&f.file->f_path, stat);
 		fdput(f);
 	}
 	return error;
 }
+EXPORT_SYMBOL(vfs_fstatx);
+
+/**
+ * vfs_fstat - Get basic attributes by file descriptor
+ * @fd: The file descriptor referring to the file of interest
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_getattr().  The main difference is
+ * that it uses a file descriptor to determine the file location.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_fstat(unsigned int fd, struct kstat *stat)
+{
+	stat->query_flags = 0;
+	stat->request_mask = STATX_BASIC_STATS;
+	return vfs_fstatx(fd, stat);
+}
 EXPORT_SYMBOL(vfs_fstat);
 
-int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
-		int flag)
+/**
+ * vfs_statx - Get basic and extra attributes by filename
+ * @dfd: A file descriptor representing the base dir for a relative filename
+ * @filename: The name of the file of interest
+ * @flags: Flags to control the query
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_xgetattr().  The main difference is
+ * that it uses a filename and base directory to determine the file location.
+ * Additionally, the addition of AT_SYMLINK_NOFOLLOW to flags will prevent a
+ * symlink at the given name from being referenced.
+ *
+ * The caller must have preset stat->request_mask and stat->auxinfo as for
+ * vfs_xgetattr().  The flags are also used to load up stat->query_flags.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_statx(int dfd, const char __user *filename, int flags,
+	      struct kstat *stat)
 {
 	struct path path;
 	int error = -EINVAL;
-	unsigned int lookup_flags = 0;
+	unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
 
-	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
-		      AT_EMPTY_PATH)) != 0)
-		goto out;
+	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
+		       AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
+		return -EINVAL;
 
-	if (!(flag & AT_SYMLINK_NOFOLLOW))
-		lookup_flags |= LOOKUP_FOLLOW;
-	if (flag & AT_EMPTY_PATH)
+	if (flags & AT_SYMLINK_NOFOLLOW)
+		lookup_flags &= ~LOOKUP_FOLLOW;
+	if (flags & AT_NO_AUTOMOUNT)
+		lookup_flags &= ~LOOKUP_AUTOMOUNT;
+	if (flags & AT_EMPTY_PATH)
 		lookup_flags |= LOOKUP_EMPTY;
+	stat->query_flags = flags;
+
 retry:
 	error = user_path_at(dfd, filename, lookup_flags, &path);
 	if (error)
 		goto out;
 
-	error = vfs_getattr(&path, stat);
+	error = vfs_xgetattr(&path, stat);
 	path_put(&path);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
@@ -116,17 +236,65 @@  retry:
 out:
 	return error;
 }
+EXPORT_SYMBOL(vfs_statx);
+
+/**
+ * vfs_fstatat - Get basic attributes by filename
+ * @dfd: A file descriptor representing the base dir for a relative filename
+ * @filename: The name of the file of interest
+ * @flags: Flags to control the query
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_statx().  The difference is that it
+ * preselects basic stats only.  The flags are used to load up
+ * stat->query_flags in addition to indicating symlink handling during path
+ * resolution.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
+		int flags)
+{
+	stat->request_mask = STATX_BASIC_STATS;
+	return vfs_statx(dfd, filename, flags, stat);
+}
 EXPORT_SYMBOL(vfs_fstatat);
 
-int vfs_stat(const char __user *name, struct kstat *stat)
+/**
+ * vfs_stat - Get basic attributes by filename
+ * @filename: The name of the file of interest
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_statx().  The difference is that it
+ * preselects basic stats only, terminal symlinks are followed regardless and a
+ * remote filesystem can't be forced to query the server.  If such is desired,
+ * vfs_statx() should be used instead.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
+int vfs_stat(const char __user *filename, struct kstat *stat)
 {
-	return vfs_fstatat(AT_FDCWD, name, stat, 0);
+	stat->request_mask = STATX_BASIC_STATS;
+	return vfs_statx(AT_FDCWD, filename, 0, stat);
 }
 EXPORT_SYMBOL(vfs_stat);
 
+/**
+ * vfs_lstat - Get basic attrs by filename, without following terminal symlink
+ * @filename: The name of the file of interest
+ * @stat: The result structure to fill in.
+ *
+ * This function is a wrapper around vfs_statx().  The difference is that it
+ * preselects basic stats only, terminal symlinks are note followed regardless
+ * and a remote filesystem can't be forced to query the server.  If such is
+ * desired, vfs_statx() should be used instead.
+ *
+ * 0 will be returned on success, and a -ve error code if unsuccessful.
+ */
 int vfs_lstat(const char __user *name, struct kstat *stat)
 {
-	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
+	stat->request_mask = STATX_BASIC_STATS;
+	return vfs_statx(AT_FDCWD, name, AT_SYMLINK_NOFOLLOW, stat);
 }
 EXPORT_SYMBOL(vfs_lstat);
 
@@ -141,7 +309,7 @@  static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta
 {
 	static int warncount = 5;
 	struct __old_kernel_stat tmp;
-	
+
 	if (warncount > 0) {
 		warncount--;
 		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
@@ -166,7 +334,7 @@  static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta
 #if BITS_PER_LONG == 32
 	if (stat->size > MAX_NON_LFS)
 		return -EOVERFLOW;
-#endif	
+#endif
 	tmp.st_size = stat->size;
 	tmp.st_atime = stat->atime.tv_sec;
 	tmp.st_mtime = stat->mtime.tv_sec;
@@ -445,6 +613,81 @@  SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
 }
 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
 
+/*
+ * Set the statx results.
+ */
+static long statx_set_result(struct kstat *stat, struct statx __user *buffer)
+{
+	uid_t uid = from_kuid_munged(current_user_ns(), stat->uid);
+	gid_t gid = from_kgid_munged(current_user_ns(), stat->gid);
+
+#define __put_timestamp(kts, uts) (				\
+		__put_user(kts.tv_sec,	uts##_s		) ||	\
+		__put_user(kts.tv_nsec,	uts##_ns	))
+
+	if (__put_user(stat->result_mask,	&buffer->st_mask	) ||
+	    __put_user(stat->mode,		&buffer->st_mode	) ||
+	    __clear_user(&buffer->__spare0, sizeof(buffer->__spare0))	  ||
+	    __put_user(stat->nlink,		&buffer->st_nlink	) ||
+	    __put_user(uid,			&buffer->st_uid		) ||
+	    __put_user(gid,			&buffer->st_gid		) ||
+	    __put_user(stat->information,	&buffer->st_information	) ||
+	    __put_user(stat->blksize,		&buffer->st_blksize	) ||
+	    __put_user(MAJOR(stat->rdev),	&buffer->st_rdev_major	) ||
+	    __put_user(MINOR(stat->rdev),	&buffer->st_rdev_minor	) ||
+	    __put_user(MAJOR(stat->dev),	&buffer->st_dev_major	) ||
+	    __put_user(MINOR(stat->dev),	&buffer->st_dev_minor	) ||
+	    __put_timestamp(stat->atime,	&buffer->st_atime	) ||
+	    __put_timestamp(stat->btime,	&buffer->st_btime	) ||
+	    __put_timestamp(stat->ctime,	&buffer->st_ctime	) ||
+	    __put_timestamp(stat->mtime,	&buffer->st_mtime	) ||
+	    __put_user(stat->ino,		&buffer->st_ino		) ||
+	    __put_user(stat->size,		&buffer->st_size	) ||
+	    __put_user(stat->blocks,		&buffer->st_blocks	) ||
+	    __put_user(stat->version,		&buffer->st_version	) ||
+	    __put_user(stat->ioc_flags,		&buffer->st_ioc_flags	) ||
+	    __clear_user(&buffer->__spare1, sizeof(buffer->__spare1))	  ||
+	    __clear_user(&buffer->__spare2, sizeof(buffer->__spare2)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * sys_statx - System call to get enhanced stats
+ * @dfd: Base directory to pathwalk from *or* fd to stat.
+ * @filename: File to stat *or* NULL.
+ * @flags: AT_* flags to control pathwalk.
+ * @mask: Parts of statx struct actually required.
+ * @buffer: Result buffer.
+ *
+ * Note that if filename is NULL, then it does the equivalent of fstat() using
+ * dfd to indicate the file of interest.
+ */
+SYSCALL_DEFINE5(statx,
+		int, dfd, const char __user *, filename, unsigned, flags,
+		unsigned int, mask,
+		struct statx __user *, buffer)
+{
+	struct kstat stat;
+	int error;
+
+	if (!access_ok(VERIFY_WRITE, buffer, sizeof(*buffer)))
+		return -EFAULT;
+
+	memset(&stat, 0, sizeof(stat));
+	stat.query_flags = flags;
+	stat.request_mask = mask & STATX_ALL_STATS;
+
+	if (filename)
+		error = vfs_statx(dfd, filename, flags, &stat);
+	else
+		error = vfs_fstatx(dfd, &stat);
+	if (error)
+		return error;
+	return statx_set_result(&stat, buffer);
+}
+
 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
 void __inode_add_bytes(struct inode *inode, loff_t bytes)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 72d8a844c692..8fb641ac1027 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2760,8 +2760,9 @@  extern void kfree_put_link(struct inode *, void *);
 extern void free_page_put_link(struct inode *, void *);
 extern int generic_readlink(struct dentry *, char __user *, int);
 extern void generic_fillattr(struct inode *, struct kstat *);
-int vfs_getattr_nosec(struct path *path, struct kstat *stat);
+extern int vfs_xgetattr_nosec(struct path *path, struct kstat *stat);
 extern int vfs_getattr(struct path *, struct kstat *);
+extern int vfs_xgetattr(struct path *, struct kstat *);
 void __inode_add_bytes(struct inode *inode, loff_t bytes);
 void inode_add_bytes(struct inode *inode, loff_t bytes);
 void __inode_sub_bytes(struct inode *inode, loff_t bytes);
@@ -2777,6 +2778,8 @@  extern int vfs_stat(const char __user *, struct kstat *);
 extern int vfs_lstat(const char __user *, struct kstat *);
 extern int vfs_fstat(unsigned int, struct kstat *);
 extern int vfs_fstatat(int , const char __user *, struct kstat *, int);
+extern int vfs_xstat(int, const char __user *, int, struct kstat *);
+extern int vfs_xfstat(unsigned int, struct kstat *);
 
 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		    unsigned long arg);
diff --git a/include/linux/stat.h b/include/linux/stat.h
index 075cb0c7eb2a..b6bcbe17bfc2 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -19,6 +19,12 @@ 
 #include <linux/uidgid.h>
 
 struct kstat {
+	u32		query_flags;		/* Operational flags */
+#define KSTAT_QUERY_FLAGS (AT_FORCE_ATTR_SYNC | AT_NO_ATTR_SYNC)
+	u32		request_mask;		/* What fields the user asked for */
+	u32		result_mask;		/* What fields the user got */
+	u32		information;
+	u64		ioc_flags;		/* Inode flags (FS_IOC_GETFLAGS) */
 	u64		ino;
 	dev_t		dev;
 	umode_t		mode;
@@ -27,11 +33,13 @@  struct kstat {
 	kgid_t		gid;
 	dev_t		rdev;
 	loff_t		size;
-	struct timespec  atime;
+	struct timespec	atime;
 	struct timespec	mtime;
 	struct timespec	ctime;
-	unsigned long	blksize;
-	unsigned long long	blocks;
+	struct timespec	btime;			/* File creation time */
+	uint32_t	blksize;		/* Preferred I/O size */
+	u64		blocks;
+	u64		version;		/* Data version */
 };
 
 #endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a460e2ef2843..09eb280f6bf6 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -48,6 +48,7 @@  struct stat;
 struct stat64;
 struct statfs;
 struct statfs64;
+struct statx;
 struct __sysctl_args;
 struct sysinfo;
 struct timespec;
@@ -886,5 +887,7 @@  asmlinkage long sys_execveat(int dfd, const char __user *filename,
 			const char __user *const __user *envp, int flags);
 
 asmlinkage long sys_membarrier(int cmd, int flags);
+asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
+			  unsigned mask, struct statx __user *buffer);
 
 #endif
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index beed138bd359..5c8143b04ff7 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -62,6 +62,8 @@ 
 #define AT_SYMLINK_FOLLOW	0x400   /* Follow symbolic links.  */
 #define AT_NO_AUTOMOUNT		0x800	/* Suppress terminal automount traversal */
 #define AT_EMPTY_PATH		0x1000	/* Allow empty relative pathname */
+#define AT_FORCE_ATTR_SYNC	0x2000	/* Force the attributes to be sync'd with the server */
+#define AT_NO_ATTR_SYNC		0x4000	/* Don't sync attributes with the server */
 
 
 #endif /* _UAPI_LINUX_FCNTL_H */
diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
index 7fec7e36d921..41a5412e7ad5 100644
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -1,6 +1,7 @@ 
 #ifndef _UAPI_LINUX_STAT_H
 #define _UAPI_LINUX_STAT_H
 
+#include <linux/types.h>
 
 #if defined(__KERNEL__) || !defined(__GLIBC__) || (__GLIBC__ < 2)
 
@@ -41,5 +42,120 @@ 
 
 #endif
 
+/*
+ * Structures for the extended file attribute retrieval system call
+ * (statx()).
+ *
+ * The caller passes a mask of what they're specifically interested in as a
+ * parameter to statx().  What statx() actually got will be indicated in
+ * st_mask upon return.
+ *
+ * For each bit in the mask argument:
+ *
+ * - if the datum is not available at all, the field and the bit will both be
+ *   cleared;
+ *
+ * - otherwise, if explicitly requested:
+ *
+ *   - the datum will be synchronised to the server if AT_FORCE_ATTR_SYNC is
+ *     set or if the datum is considered out of date, and
+ *
+ *   - the field will be filled in and the bit will be set;
+ *
+ * - otherwise, if not requested, but available in approximate form without any
+ *   effort, it will be filled in anyway, and the bit will be set upon return
+ *   (it might not be up to date, however, and no attempt will be made to
+ *   synchronise the internal state first);
+ *
+ * - otherwise the field and the bit will be cleared before returning.
+ *
+ * Items in STATX_BASIC_STATS may be marked unavailable on return, but they
+ * will have values installed for compatibility purposes so that stat() and
+ * co. can be emulated in userspace.
+ */
+struct statx {
+	/* 0x00 */
+	__u32	st_mask;	/* What results were written [uncond] */
+	__u32	st_information;	/* Information about the file [uncond] */
+	__u16	st_mode;	/* File mode */
+	__u16	__spare0[1];
+	/* 0xc */
+	__u32	st_nlink;	/* Number of hard links */
+	__u32	st_uid;		/* User ID of owner */
+	__u32	st_gid;		/* Group ID of owner */
+	/* 0x18 - I/O parameters */
+	__u32	st_blksize;	/* Preferred general I/O size [uncond] */
+	__u32	__spare1[3];
+	/* 0x28 */
+	__u32	st_rdev_major;	/* Device ID of special file */
+	__u32	st_rdev_minor;
+	__u32	st_dev_major;	/* ID of device containing file [uncond] */
+	__u32	st_dev_minor;
+	/* 0x38 */
+	__s32	st_atime_ns;	/* Last access time (ns part) */
+	__s32	st_btime_ns;	/* File creation time (ns part) */
+	__s32	st_ctime_ns;	/* Last attribute change time (ns part) */
+	__s32	st_mtime_ns;	/* Last data modification time (ns part) */
+	/* 0x48 */
+	__s64	st_atime_s;	/* Last access time */
+	__s64	st_btime_s;	/* File creation time */
+	__s64	st_ctime_s;	/* Last attribute change time */
+	__s64	st_mtime_s;	/* Last data modification time */
+	/* 0x68 */
+	__u64	st_ino;		/* Inode number */
+	__u64	st_size;	/* File size */
+	__u64	st_blocks;	/* Number of 512-byte blocks allocated */
+	__u64	st_version;	/* Data version number */
+	__u64	st_ioc_flags;	/* As FS_IOC_GETFLAGS */
+	/* 0x90 */
+	__u64	__spare2[14];	/* Spare space for future expansion */
+	/* 0x100 */
+};
+
+/*
+ * Flags to be st_mask
+ *
+ * Query request/result mask for statx() and struct statx::st_mask.
+ *
+ * These bits should be set in the mask argument of statx() to request
+ * particular items when calling statx().
+ */
+#define STATX_MODE		0x00000001U	/* Want/got st_mode */
+#define STATX_NLINK		0x00000002U	/* Want/got st_nlink */
+#define STATX_UID		0x00000004U	/* Want/got st_uid */
+#define STATX_GID		0x00000008U	/* Want/got st_gid */
+#define STATX_RDEV		0x00000010U	/* Want/got st_rdev */
+#define STATX_ATIME		0x00000020U	/* Want/got st_atime */
+#define STATX_MTIME		0x00000040U	/* Want/got st_mtime */
+#define STATX_CTIME		0x00000080U	/* Want/got st_ctime */
+#define STATX_INO		0x00000100U	/* Want/got st_ino */
+#define STATX_SIZE		0x00000200U	/* Want/got st_size */
+#define STATX_BLOCKS		0x00000400U	/* Want/got st_blocks */
+#define STATX_BASIC_STATS	0x000007ffU	/* The stuff in the normal stat struct */
+#define STATX_BTIME		0x00000800U	/* Want/got st_btime */
+#define STATX_VERSION		0x00001000U	/* Want/got st_version */
+#define STATX_IOC_FLAGS		0x00002000U	/* Want/got FS_IOC_GETFLAGS */
+#define STATX_ALL_STATS		0x00003fffU	/* All supported stats */
+
+/*
+ * Flags to be found in st_information
+ *
+ * These give information about the features or the state of a file that might
+ * be of use to ordinary userspace programs such as GUIs or ls rather than
+ * specialised tools.
+ *
+ * Additional information may be found in st_ioc_flags and we try not to
+ * overlap with it.
+ */
+#define STATX_INFO_ENCRYPTED		0x00000001U /* File is encrypted */
+#define STATX_INFO_TEMPORARY		0x00000002U /* File is temporary (NTFS/CIFS) */
+#define STATX_INFO_FABRICATED		0x00000004U /* File was made up by filesystem */
+#define STATX_INFO_KERNEL_API		0x00000008U /* File is kernel API (eg: procfs/sysfs) */
+#define STATX_INFO_REMOTE		0x00000010U /* File is remote */
+#define STATX_INFO_OFFLINE		0x00000020U /* File is offline (CIFS) */
+#define STATX_INFO_AUTOMOUNT		0x00000040U /* Dir is automount trigger */
+#define STATX_INFO_AUTODIR		0x00000080U /* Dir provides unlisted automounts */
+#define STATX_INFO_NONSYSTEM_OWNERSHIP	0x00000100U /* File has non-system ownership details */
+#define STATX_INFO_REPARSE_POINT	0x00000200U /* File is reparse point (NTFS/CIFS) */
 
 #endif /* _UAPI_LINUX_STAT_H */
diff --git a/samples/Makefile b/samples/Makefile
index f00257bcc5a7..e2db7f5672a0 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -1,4 +1,5 @@ 
 # Makefile for Linux samples code
 
 obj-$(CONFIG_SAMPLES)	+= kobject/ kprobes/ trace_events/ livepatch/ \
-			   hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/
+			   hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ \
+			   statx/
diff --git a/samples/statx/Makefile b/samples/statx/Makefile
new file mode 100644
index 000000000000..6765dabc4c8d
--- /dev/null
+++ b/samples/statx/Makefile
@@ -0,0 +1,10 @@ 
+# kbuild trick to avoid linker error. Can be omitted if a module is built.
+obj- := dummy.o
+
+# List of programs to build
+hostprogs-y := test-statx
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
+
+HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
diff --git a/samples/statx/test-statx.c b/samples/statx/test-statx.c
new file mode 100644
index 000000000000..86bbf4e945f4
--- /dev/null
+++ b/samples/statx/test-statx.c
@@ -0,0 +1,273 @@ 
+/* Test the statx() system call
+ *
+ * Copyright (C) 2015 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define _GNU_SOURCE
+#define _ATFILE_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <sys/stat.h>
+
+#define AT_FORCE_ATTR_SYNC	0x2000
+#define AT_NO_ATTR_SYNC		0x4000
+
+#define __NR_statx 325
+
+static __attribute__((unused))
+ssize_t statx(int dfd, const char *filename, unsigned flags,
+	      unsigned int mask, struct statx *buffer)
+{
+	return syscall(__NR_statx, dfd, filename, flags, mask, buffer);
+}
+
+static void print_time(const char *field, __s64 tv_sec, __s32 tv_nsec)
+{
+	struct tm tm;
+	time_t tim;
+	char buffer[100];
+	int len;
+
+	tim = tv_sec;
+	if (!localtime_r(&tim, &tm)) {
+		perror("localtime_r");
+		exit(1);
+	}
+	len = strftime(buffer, 100, "%F %T", &tm);
+	if (len == 0) {
+		perror("strftime");
+		exit(1);
+	}
+	printf("%s", field);
+	fwrite(buffer, 1, len, stdout);
+	printf(".%09u", tv_nsec);
+	len = strftime(buffer, 100, "%z", &tm);
+	if (len == 0) {
+		perror("strftime2");
+		exit(1);
+	}
+	fwrite(buffer, 1, len, stdout);
+	printf("\n");
+}
+
+static void dump_statx(struct statx *stx)
+{
+	char buffer[256], ft = '?';
+
+	printf("results=%x\n", stx->st_mask);
+
+	printf(" ");
+	if (stx->st_mask & STATX_SIZE)
+		printf(" Size: %-15llu", (unsigned long long)stx->st_size);
+	if (stx->st_mask & STATX_BLOCKS)
+		printf(" Blocks: %-10llu", (unsigned long long)stx->st_blocks);
+	printf(" IO Block: %-6llu ", (unsigned long long)stx->st_blksize);
+	if (stx->st_mask & STATX_MODE) {
+		switch (stx->st_mode & S_IFMT) {
+		case S_IFIFO:	printf(" FIFO\n");			ft = 'p'; break;
+		case S_IFCHR:	printf(" character special file\n");	ft = 'c'; break;
+		case S_IFDIR:	printf(" directory\n");			ft = 'd'; break;
+		case S_IFBLK:	printf(" block special file\n");	ft = 'b'; break;
+		case S_IFREG:	printf(" regular file\n");		ft = '-'; break;
+		case S_IFLNK:	printf(" symbolic link\n");		ft = 'l'; break;
+		case S_IFSOCK:	printf(" socket\n");			ft = 's'; break;
+		default:
+			printf("unknown type (%o)\n", stx->st_mode & S_IFMT);
+			break;
+		}
+	}
+
+	sprintf(buffer, "%02x:%02x", stx->st_dev_major, stx->st_dev_minor);
+	printf("Device: %-15s", buffer);
+	if (stx->st_mask & STATX_INO)
+		printf(" Inode: %-11llu", (unsigned long long) stx->st_ino);
+	if (stx->st_mask & STATX_SIZE)
+		printf(" Links: %-5u", stx->st_nlink);
+	if (stx->st_mask & STATX_RDEV)
+		printf(" Device type: %u,%u", stx->st_rdev_major, stx->st_rdev_minor);
+	printf("\n");
+
+	if (stx->st_mask & STATX_MODE)
+		printf("Access: (%04o/%c%c%c%c%c%c%c%c%c%c)  ",
+		       stx->st_mode & 07777,
+		       ft,
+		       stx->st_mode & S_IRUSR ? 'r' : '-',
+		       stx->st_mode & S_IWUSR ? 'w' : '-',
+		       stx->st_mode & S_IXUSR ? 'x' : '-',
+		       stx->st_mode & S_IRGRP ? 'r' : '-',
+		       stx->st_mode & S_IWGRP ? 'w' : '-',
+		       stx->st_mode & S_IXGRP ? 'x' : '-',
+		       stx->st_mode & S_IROTH ? 'r' : '-',
+		       stx->st_mode & S_IWOTH ? 'w' : '-',
+		       stx->st_mode & S_IXOTH ? 'x' : '-');
+	if (stx->st_mask & STATX_UID)
+		printf("Uid: %5d   ", stx->st_uid);
+	if (stx->st_mask & STATX_GID)
+		printf("Gid: %5d\n", stx->st_gid);
+
+	if (stx->st_mask & STATX_ATIME)
+		print_time("Access: ", stx->st_atime_s, stx->st_atime_ns);
+	if (stx->st_mask & STATX_MTIME)
+		print_time("Modify: ", stx->st_mtime_s, stx->st_mtime_ns);
+	if (stx->st_mask & STATX_CTIME)
+		print_time("Change: ", stx->st_ctime_s, stx->st_ctime_ns);
+	if (stx->st_mask & STATX_BTIME)
+		print_time(" Birth: ", stx->st_btime_s, stx->st_btime_ns);
+
+	if (stx->st_mask & STATX_VERSION)
+		printf("Data version: %llxh\n",
+		       (unsigned long long)stx->st_version);
+
+	if (stx->st_mask & STATX_IOC_FLAGS) {
+		unsigned char bits;
+		int loop, byte;
+
+		static char flag_representation[32 + 1] =
+			/* FS_IOC_GETFLAGS flags: */
+			"?????ASH"	/* 31-24	0x00000000-ff000000 */
+			"????ehTD"	/* 23-16	0x00000000-00ff0000 */
+			"tj?IE?XZ"	/* 15- 8	0x00000000-0000ff00 */
+			"AdaiScus"	/*  7- 0	0x00000000-000000ff */
+			;
+
+		printf("Inode flags: %08llx (",
+		       (unsigned long long)stx->st_ioc_flags);
+		for (byte = 32 - 8; byte >= 0; byte -= 8) {
+			bits = stx->st_ioc_flags >> byte;
+			for (loop = 7; loop >= 0; loop--) {
+				int bit = byte + loop;
+
+				if (bits & 0x80)
+					putchar(flag_representation[31 - bit]);
+				else
+					putchar('-');
+				bits <<= 1;
+			}
+			if (byte)
+				putchar(' ');
+		}
+		printf(")\n");
+	}
+
+	if (stx->st_information) {
+		unsigned char bits;
+		int loop, byte;
+
+		static char info_representation[32 + 1] =
+			/* STATX_INFO_ flags: */
+			"????????"	/* 31-24	0x00000000-ff000000 */
+			"????????"	/* 23-16	0x00000000-00ff0000 */
+			"??????Rn"	/* 15- 8	0x00000000-0000ff00 */
+			"dmorkfte"	/*  7- 0	0x00000000-000000ff */
+			;
+
+		printf("Information: %08x (", stx->st_information);
+		for (byte = 32 - 8; byte >= 0; byte -= 8) {
+			bits = stx->st_information >> byte;
+			for (loop = 7; loop >= 0; loop--) {
+				int bit = byte + loop;
+
+				if (bits & 0x80)
+					putchar(info_representation[31 - bit]);
+				else
+					putchar('-');
+				bits <<= 1;
+			}
+			if (byte)
+				putchar(' ');
+		}
+		printf(")\n");
+	}
+
+	printf("IO-blocksize: blksize=%u\n", stx->st_blksize);
+}
+
+static void dump_hex(unsigned long long *data, int from, int to)
+{
+	unsigned offset, print_offset = 1, col = 0;
+
+	from /= 8;
+	to = (to + 7) / 8;
+
+	for (offset = from; offset < to; offset++) {
+		if (print_offset) {
+			printf("%04x: ", offset * 8);
+			print_offset = 0;
+		}
+		printf("%016llx", data[offset]);
+		col++;
+		if ((col & 3) == 0) {
+			printf("\n");
+			print_offset = 1;
+		} else {
+			printf(" ");
+		}
+	}
+
+	if (!print_offset)
+		printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct statx stx;
+	int ret, raw = 0, atflag = AT_SYMLINK_NOFOLLOW;
+
+	unsigned int mask = STATX_ALL_STATS;
+
+	for (argv++; *argv; argv++) {
+		if (strcmp(*argv, "-F") == 0) {
+			atflag |= AT_FORCE_ATTR_SYNC;
+			continue;
+		}
+		if (strcmp(*argv, "-N") == 0) {
+			atflag |= AT_NO_ATTR_SYNC;
+			continue;
+		}
+		if (strcmp(*argv, "-L") == 0) {
+			atflag &= ~AT_SYMLINK_NOFOLLOW;
+			continue;
+		}
+		if (strcmp(*argv, "-O") == 0) {
+			mask &= ~STATX_BASIC_STATS;
+			continue;
+		}
+		if (strcmp(*argv, "-A") == 0) {
+			atflag |= AT_NO_AUTOMOUNT;
+			continue;
+		}
+		if (strcmp(*argv, "-R") == 0) {
+			raw = 1;
+			continue;
+		}
+
+		memset(&stx, 0xbf, sizeof(stx));
+		ret = statx(AT_FDCWD, *argv, atflag, mask, &stx);
+		printf("statx(%s) = %d\n", *argv, ret);
+		if (ret < 0) {
+			perror(*argv);
+			exit(1);
+		}
+
+		if (raw)
+			dump_hex((unsigned long long *)&stx, 0, sizeof(stx));
+
+		dump_statx(&stx);
+	}
+	return 0;
+}