<feed xmlns='http://www.w3.org/2005/Atom'>
<title>lwn.git/fs/cifs/cifsfs.h, branch standardize-docs</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=standardize-docs</id>
<link rel='self' href='http://mirrors.hust.edu.cn/git/lwn.git/atom?h=standardize-docs'/>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/'/>
<updated>2017-04-07T13:04:41+00:00</updated>
<entry>
<title>Introduce cifs_copy_file_range()</title>
<updated>2017-04-07T13:04:41+00:00</updated>
<author>
<name>Sachin Prabhu</name>
<email>sprabhu@redhat.com</email>
</author>
<published>2017-02-10T10:33:51+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=620d8745b35daaf507186c26b40c7ea02aed131e'/>
<id>urn:sha1:620d8745b35daaf507186c26b40c7ea02aed131e</id>
<content type='text'>
The earlier changes to copy range for cifs unintentionally disabled the more
common form of server side copy.

The patch introduces the file_operations helper cifs_copy_file_range()
which is used by the syscall copy_file_range. The new file operations
helper allows us to perform server side copies for SMB2.0 and 2.1
servers as well as SMB 3.0+ servers which do not support the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE.

The new helper uses the ioctl FSCTL_SRV_COPYCHUNK_WRITE to perform
server side copies. The helper is called by vfs_copy_file_range() only
once an attempt to clone the file using the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE has failed.

Signed-off-by: Sachin Prabhu &lt;sprabhu@redhat.com&gt;
Reviewed-by: Pavel Shilovsky &lt;pshilov@microsoft.com&gt;
CC: Stable  &lt;stable@vger.kernel.org&gt;
Signed-off-by: Steve French &lt;smfrench@gmail.com&gt;
</content>
</entry>
<entry>
<title>statx: Add a system call to make enhanced file info available</title>
<updated>2017-03-03T01:51:15+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2017-01-31T16:46:22+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=a528d35e8bfcc521d7cb70aaf03e1bd296c8493f'/>
<id>urn:sha1:a528d35e8bfcc521d7cb70aaf03e1bd296c8493f</id>
<content type='text'>
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

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

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

A number of requests were gathered for features to be included.  The
following have been included:

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

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

 (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
     __s64).

 (4) 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 (stx_btime).

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

 (5) 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] (AT_STATX_DONT_SYNC).

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

And the following have been left out for future extension:

 (7) 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.

     (There's disagreement on the exact semantics of a single field, since
     not all filesystems do this the same way).

 (8) 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].

 (9) 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 and caused disagreement as to
     whether it's a security hole or not).

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

     (No particular data were offered, but things like last backup
     timestamp, the data version number and the DOS archive bit would come
     into this category).

(11) 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...

     (This requires a separate system call - I have an fsinfo() call idea
     for this).

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

     (Deferred to fsinfo).

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

     (Deferred to fsinfo).

(14) 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).

     (Some attributes are made available in stx_attributes, but the general
     feeling was that the IOC flags were to ext[234]-specific and shouldn't
     be exposed through statx this way).

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

     (Deferred, probably to fsinfo.  Finding out if there's an ACL or
     seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

     (A __reserved field has been left in the statx_timestamp struct for
     this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
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, in a
similar way to fstatat().  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.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

 (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
     respect.

 (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
     its attributes with the server - which might require data writeback to
     occur to get the timestamps correct.

 (3) AT_STATX_DONT_SYNC 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().  It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the 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_timestamp {
		__s64	tv_sec;
		__s32	tv_nsec;
		__s32	__reserved;
	};

	struct statx {
		__u32	stx_mask;
		__u32	stx_blksize;
		__u64	stx_attributes;
		__u32	stx_nlink;
		__u32	stx_uid;
		__u32	stx_gid;
		__u16	stx_mode;
		__u16	__spare0[1];
		__u64	stx_ino;
		__u64	stx_size;
		__u64	stx_blocks;
		__u64	__spare1[1];
		struct statx_timestamp	stx_atime;
		struct statx_timestamp	stx_btime;
		struct statx_timestamp	stx_ctime;
		struct statx_timestamp	stx_mtime;
		__u32	stx_rdev_major;
		__u32	stx_rdev_minor;
		__u32	stx_dev_major;
		__u32	stx_dev_minor;
		__u64	__spare2[14];
	};

The defined bits in request_mask and stx_mask are:

	STATX_TYPE		Want/got stx_mode &amp; S_IFMT
	STATX_MODE		Want/got stx_mode &amp; ~S_IFMT
	STATX_NLINK		Want/got stx_nlink
	STATX_UID		Want/got stx_uid
	STATX_GID		Want/got stx_gid
	STATX_ATIME		Want/got stx_atime{,_ns}
	STATX_MTIME		Want/got stx_mtime{,_ns}
	STATX_CTIME		Want/got stx_ctime{,_ns}
	STATX_INO		Want/got stx_ino
	STATX_SIZE		Want/got stx_size
	STATX_BLOCKS		Want/got stx_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got stx_btime{,_ns}
	STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

	STATX_ATTR_COMPRESSED		File is compressed by the fs
	STATX_ATTR_IMMUTABLE		File is marked immutable
	STATX_ATTR_APPEND		File is append-only
	STATX_ATTR_NODUMP		File is not to be dumped
	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

	KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

	STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

 (0) stx_dev_*, stx_blksize.

     These are local system information and are always available.

 (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
     stx_size, stx_blocks.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in stx_mask will be set to indicate whether they
     actually have valid values.

     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 stx_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

     Note that there are instances where the type might not be valid, for
     instance Windows reparse points.

 (2) stx_rdev_*.

     This will be set only if stx_mode indicates we're looking at a
     blockdev or a chardev, otherwise will be 0.

 (3) stx_btime.

     Similar to (1), except this will be set to 0 if it doesn't exist.

=======
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 AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:26           Inode: 1703937     Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

	[root@andromeda ~]# /tmp/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:27           Inode: 2           Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
</entry>
<entry>
<title>cifs: don't use -&gt;d_time</title>
<updated>2016-09-16T10:44:21+00:00</updated>
<author>
<name>Miklos Szeredi</name>
<email>mszeredi@redhat.com</email>
</author>
<published>2016-09-16T10:44:21+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=a00be0e31f8df453ecbaaa4ba78d2ef935ab252e'/>
<id>urn:sha1:a00be0e31f8df453ecbaaa4ba78d2ef935ab252e</id>
<content type='text'>
Use d_fsdata instead, which is the same size.  Introduce helpers to hide
the typecasts.

Signed-off-by: Miklos Szeredi &lt;mszeredi@redhat.com&gt;
Cc: Steve French &lt;sfrench@samba.org&gt;
</content>
</entry>
<entry>
<title>Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6</title>
<updated>2016-05-18T17:01:47+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-05-18T17:01:47+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=8908c94d6cd7513ba4512295abc945a6ff7f979c'/>
<id>urn:sha1:8908c94d6cd7513ba4512295abc945a6ff7f979c</id>
<content type='text'>
Pull cifs updates from Steve French:
 "Various small CIFS and SMB3 fixes (including some for stable)"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  remove directory incorrectly tries to set delete on close on non-empty directories
  Update cifs.ko version to 2.09
  fs/cifs: correctly to anonymous authentication for the NTLM(v2) authentication
  fs/cifs: correctly to anonymous authentication for the NTLM(v1) authentication
  fs/cifs: correctly to anonymous authentication for the LANMAN authentication
  fs/cifs: correctly to anonymous authentication via NTLMSSP
  cifs: remove any preceding delimiter from prefix_path
  cifs: Use file_dentry()
</content>
</entry>
<entry>
<title>Update cifs.ko version to 2.09</title>
<updated>2016-05-17T19:09:34+00:00</updated>
<author>
<name>Steve French</name>
<email>smfrench@gmail.com</email>
</author>
<published>2016-05-10T13:24:05+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=5a4f7e8e7ff5e81f57b08797cca41d307878dfc7'/>
<id>urn:sha1:5a4f7e8e7ff5e81f57b08797cca41d307878dfc7</id>
<content type='text'>
Signed-off-by: Steven French &lt;steve.french@primarydata.com&gt;
</content>
</entry>
<entry>
<title>cifs: Switch to generic xattr handlers</title>
<updated>2016-04-23T19:33:03+00:00</updated>
<author>
<name>Andreas Gruenbacher</name>
<email>agruenba@redhat.com</email>
</author>
<published>2016-04-22T10:11:38+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=a9ae008f407b50fc92ef19588d2ea2be13a7f5e2'/>
<id>urn:sha1:a9ae008f407b50fc92ef19588d2ea2be13a7f5e2</id>
<content type='text'>
Use xattr handlers for resolving attribute names.  The amount of setup
code required on cifs is nontrivial, so use the same get and set
functions for all handlers, with switch statements for the different
types of attributes in them.

The set_EA handler can handle NULL values, so we don't need a separate
removexattr function anymore.  Remove the cifs_dbg statements related to
xattr name resolution; they don't add much.  Don't build xattr.o when
CONFIG_CIFS_XATTR is not defined.

Signed-off-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
</entry>
<entry>
<title>-&gt;getxattr(): pass dentry and inode as separate arguments</title>
<updated>2016-04-11T04:48:00+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2016-04-11T04:48:00+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=ce23e640133484eebc20ca7b7668388213e11327'/>
<id>urn:sha1:ce23e640133484eebc20ca7b7668388213e11327</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
</entry>
<entry>
<title>Fix cifs_uniqueid_to_ino_t() function for s390x</title>
<updated>2016-02-29T06:46:55+00:00</updated>
<author>
<name>Yadan Fan</name>
<email>ydfan@novell.com</email>
</author>
<published>2016-02-29T06:44:57+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=1ee9f4bd1a97026a7b2d7ae9f1f74b45680d0003'/>
<id>urn:sha1:1ee9f4bd1a97026a7b2d7ae9f1f74b45680d0003</id>
<content type='text'>
This issue is caused by commit 02323db17e3a7 ("cifs: fix
cifs_uniqueid_to_ino_t not to ever return 0"), when BITS_PER_LONG
is 64 on s390x, the corresponding cifs_uniqueid_to_ino_t()
function will cast 64-bit fileid to 32-bit by using (ino_t)fileid,
because ino_t (typdefed __kernel_ino_t) is int type.

It's defined in arch/s390/include/uapi/asm/posix_types.h

    #ifndef __s390x__

    typedef unsigned long   __kernel_ino_t;
    ...
    #else /* __s390x__ */

    typedef unsigned int    __kernel_ino_t;

So the #ifdef condition is wrong for s390x, we can just still use
one cifs_uniqueid_to_ino_t() function with comparing sizeof(ino_t)
and sizeof(u64) to choose the correct execution accordingly.

Signed-off-by: Yadan Fan &lt;ydfan@suse.com&gt;
CC: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Steve French &lt;smfrench@gmail.com&gt;
</content>
</entry>
<entry>
<title>Merge branch 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs</title>
<updated>2016-01-13T00:30:34+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-01-13T00:30:34+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=fce205e9da8e063aa1cf3d6583c1a9ed2b82f3f0'/>
<id>urn:sha1:fce205e9da8e063aa1cf3d6583c1a9ed2b82f3f0</id>
<content type='text'>
Pull vfs copy_file_range updates from Al Viro:
 "Several series around copy_file_range/CLONE"

* 'work.copy_file_range' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  btrfs: use new dedupe data function pointer
  vfs: hoist the btrfs deduplication ioctl to the vfs
  vfs: wire up compat ioctl for CLONE/CLONE_RANGE
  cifs: avoid unused variable and label
  nfsd: implement the NFSv4.2 CLONE operation
  nfsd: Pass filehandle to nfs4_preprocess_stateid_op()
  vfs: pull btrfs clone API to vfs layer
  locks: new locks_mandatory_area calling convention
  vfs: Add vfs_copy_file_range() support for pagecache copies
  btrfs: add .copy_file_range file operation
  x86: add sys_copy_file_range to syscall tables
  vfs: add copy_file_range syscall and vfs helper
</content>
</entry>
<entry>
<title>switch -&gt;get_link() to delayed_call, kill -&gt;put_link()</title>
<updated>2015-12-30T18:01:03+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2015-12-29T20:58:39+00:00</published>
<link rel='alternate' type='text/html' href='http://mirrors.hust.edu.cn/git/lwn.git/commit/?id=fceef393a538134f03b778c5d2519e670269342f'/>
<id>urn:sha1:fceef393a538134f03b778c5d2519e670269342f</id>
<content type='text'>
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
</entry>
</feed>
