27 Sep, 2020
4 commits
-
KSTAT_QUERY_FLAGS expands to AT_STATX_SYNC_TYPE, which itself already
is a mask. Remove the double name, especially given that the prefix
is a little confusing vs the normal AT_* flags.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
The function really obsfucates checking for valid flags and setting the
lookup flags. The fact that it returns -EINVAL through and unsigned
return value, which is then used as boolean really doesn't help either.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
This allows to keep vfs_statx static in fs/stat.c to prepare for the following
changes.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
vfs_statx_fd is only used to implement vfs_fstat. Remove vfs_statx_fd
and just implement vfs_fstat directly.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
03 Jun, 2020
2 commits
-
Pull DAX updates part one from Darrick Wong:
"After many years of LKML-wrangling about how to enable programs to
query and influence the file data access mode (DAX) when a filesystem
resides on storage devices such as persistent memory, Ira Weiny has
emerged with a proposed set of standard behaviors that has not been
shot down by anyone! We're more or less standardizing on the current
XFS behavior and adapting ext4 to do the same.This is the first of a handful pull requests that will make ext4 and
XFS present a consistent interface for user programs that care about
DAX. We add a statx attribute that programs can check to see if DAX is
enabled on a particular file. Then, we update the DAX documentation to
spell out the user-visible behaviors that filesystems will guarantee
(until the next storage industry shakeup). The on-disk inode flag has
been in XFS for a few years now.Summary:
- Clean up io_is_direct.
- Add a new statx flag to indicate when file data access is being
done via DAX (as opposed to the page cache).- Update the documentation for how system administrators and
application programmers can take advantage of the (still
experimental DAX) feature"Link: https://lore.kernel.org/lkml/20200505002016.1085071-1-ira.weiny@intel.com/
* tag 'vfs-5.8-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
Documentation/dax: Update Usage section
fs/stat: Define DAX statx attribute
fs: Remove unneeded IS_DAX() check in io_is_direct() -
Pull io_uring updates from Jens Axboe:
"A relatively quiet round, mostly just fixes and code improvements. In
particular:- Make statx just use the generic statx handler, instead of open
coding it. We don't need that anymore, as we always call it async
safe (Bijan)- Enable closing of the ring itself. Also fixes O_PATH closure (me)
- Properly name completion members (me)
- Batch reap of dead file registrations (me)
- Allow IORING_OP_POLL with double waitqueues (me)
- Add tee(2) support (Pavel)
- Remove double off read (Pavel)
- Fix overflow cancellations (Pavel)
- Improve CQ timeouts (Pavel)
- Async defer drain fixes (Pavel)
- Add support for enabling/disabling notifications on a registered
eventfd (Stefano)- Remove dead state parameter (Xiaoguang)
- Disable SQPOLL submit on dying ctx (Xiaoguang)
- Various code cleanups"
* tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block: (29 commits)
io_uring: fix overflowed reqs cancellation
io_uring: off timeouts based only on completions
io_uring: move timeouts flushing to a helper
statx: hide interfaces no longer used by io_uring
io_uring: call statx directly
statx: allow system call to be invoked from io_uring
io_uring: add io_statx structure
io_uring: get rid of manual punting in io_close
io_uring: separate DRAIN flushing into a cold path
io_uring: don't re-read sqe->off in timeout_prep()
io_uring: simplify io_timeout locking
io_uring: fix flush req->refs underflow
io_uring: don't submit sqes when ctx->refs is dying
io_uring: async task poll trigger cleanup
io_uring: add tee(2) support
splice: export do_tee()
io_uring: don't repeat valid flag list
io_uring: rename io_file_put()
io_uring: remove req->needs_fixed_files
io_uring: cleanup io_poll_remove_one() logic
...
27 May, 2020
2 commits
-
The io_uring interfaces have been replaced by do_statx() and are no
longer needed.Signed-off-by: Bijan Mottahedeh
Signed-off-by: Jens Axboe -
This is a prepatory patch to allow io_uring to invoke statx directly.
Signed-off-by: Bijan Mottahedeh
Signed-off-by: Jens Axboe
14 May, 2020
4 commits
-
Determining whether a path or file descriptor refers to a mountpoint (or
more precisely a mount root) is not trivial using current tools.Add a flag to statx that indicates whether the path or fd refers to the
root of a mount or not.Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Reported-by: Lennart Poettering
Reported-by: J. Bruce Fields
Signed-off-by: Miklos Szeredi
Reviewed-by: Christoph Hellwig -
Systemd is hacking around to get it and it's trivial to add to statx, so...
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi
Reviewed-by: Christoph Hellwig -
IS_NOATIME(inode) is defined as __IS_FLG(inode, SB_RDONLY|SB_NOATIME), so
generic_fillattr() will clear STATX_ATIME from the result_mask if the super
block is marked read only.This was probably not the intention, so fix to only clear STATX_ATIME if
the fs doesn't support atime at all.Signed-off-by: Miklos Szeredi
Acked-by: David Howells
Reviewed-by: Christoph Hellwig -
Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.Deprecate STATX_ALL in the uapi, while no damage has been done yet.
We could keep something like this around in the kernel, but there's
actually no point, since all filesystems should be explicitly checking
flags that they support and not rely on the VFS masking unknown ones out: a
flag could be known to the VFS, yet not known to the filesystem.Cc: David Howells
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi
Reviewed-by: Christoph Hellwig
04 May, 2020
1 commit
-
In order for users to determine if a file is currently operating in DAX
state (effective DAX). Define a statx attribute value and set that
attribute if the effective DAX flag is set.To go along with this we propose the following addition to the statx man
page:STATX_ATTR_DAX
The file is in the DAX (cpu direct access) state. DAX state
attempts to minimize software cache effects for both I/O and
memory mappings of this file. It requires a file system which
has been configured to support DAX.DAX generally assumes all accesses are via cpu load / store
instructions which can minimize overhead for small accesses, but
may adversely affect cpu utilization for large transfers.File I/O is done directly to/from user-space buffers and memory
mapped I/O may be performed with direct memory mappings that
bypass kernel page cache.While the DAX property tends to result in data being transferred
synchronously, it does not give the same guarantees of O_SYNC
where data and the necessary metadata are transferred together.A DAX file may support being mapped with the MAP_SYNC flag,
which enables a program to use CPU cache flush instructions to
persist CPU store operations without an explicit fsync(2). See
mmap(2) for more information.Reviewed-by: Dave Chinner
Reviewed-by: Jan Kara
Reviewed-by: Darrick J. Wong
Signed-off-by: Ira Weiny
Signed-off-by: Darrick J. Wong
21 Jan, 2020
1 commit
-
To implement an async stat, we need to provide the flags mapping and
the statx user copy. Make them available internally, through
fs/internal.h.Signed-off-by: Jens Axboe
01 Feb, 2019
1 commit
-
generic_fillattr is an optional helper that isn't used by all file
systems, move handling purely based on inode flags to vfs_getattr_nosec,
which is common code.This fixes setting this flag for file systems not using generic_fillattr
like xfs.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
29 Aug, 2018
1 commit
-
We have four generations of stat() syscalls:
- the oldstat syscalls that are only used on the older architectures
- the newstat family that is used on all 64-bit architectures but
lacked support for large files on 32-bit architectures.
- the stat64 family that is used mostly on 32-bit architectures to
replace newstat
- statx() to replace all of the above, adding 64-bit timestamps among
other things.We already compile stat64 only on those architectures that need it,
but newstat is always built, including on those that don't reference
it. This adds a new __ARCH_WANT_NEW_STAT symbol along the lines of
__ARCH_WANT_OLD_STAT and __ARCH_WANT_STAT64 to control compilation of
newstat. All architectures that need it use an explict define, the
others now get a little bit smaller, and future architecture (including
64-bit targets) won't ever see it.Acked-by: Geert Uytterhoeven
Signed-off-by: Arnd Bergmann
03 Apr, 2018
1 commit
-
Using the do_readlinkat() helper removes an in-kernel call to the
sys_readlinkat() syscall.This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.netCc: Alexander Viro
Signed-off-by: Dominik Brodowski
02 Nov, 2017
1 commit
-
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
18 Aug, 2017
1 commit
-
Provide helper __inode_get_bytes() which assumes i_lock is already
acquired. Quota code will need this to be able to use i_lock to protect
consistency of quota accounting information and inode usage.Signed-off-by: Jan Kara
10 Jun, 2017
1 commit
-
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro
03 May, 2017
1 commit
-
Pull fs/compat.c cleanups from Al Viro:
"More moving of compat syscalls from fs/compat.c to fs/*.c where the
native counterparts live.And death to compat_sys_getdents64() - the only architecture that used
to need it was ia64, and _that_ has lost biarch support quite a few
years ago"* 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs/compat.c: trim unused includes
move compat_rw_copy_check_uvector() over to fs/read_write.c
fhandle: move compat syscalls from compat.c
open: move compat syscalls from compat.c
stat: move compat syscalls from compat.c
fcntl: move compat syscalls from compat.c
readdir: move compat syscalls from compat.c
statfs: move compat syscalls from compat.c
utimes: move compat syscalls from compat.c
move compat select-related syscalls to fs/select.c
Remove compat_sys_getdents64()
28 Apr, 2017
1 commit
-
The change in commit 1e2f82d1e9d1 ("statx: Kill fd-with-NULL-path
support in favour of AT_EMPTY_PATH") to error on a NULL pathname to
statx() is inconsistent.It results in the error EINVAL for a NULL pathname. Other system calls
with similar APIs (fchownat(), fstatat(), linkat()), return EFAULT.The solution is simply to remove the EINVAL check. As I already pointed
out in [1], user_path_at*() and filename_lookup() will handle the NULL
pathname as per the other APIs, to correctly produce the error EFAULT.[1] https://lkml.org/lkml/2017/4/26/561
Signed-off-by: Michael Kerrisk
Cc: David Howells
Cc: Al Viro
Cc: Eric Sandeen
Signed-off-by: Linus Torvalds
27 Apr, 2017
1 commit
-
With the new statx() syscall, the following both allow the attributes of
the file attached to a file descriptor to be retrieved:statx(dfd, NULL, 0, ...);
and:
statx(dfd, "", AT_EMPTY_PATH, ...);
Change the code to reject the first option, though this means copying
the path and engaging pathwalk for the fstat() equivalent. dfd can be a
non-directory provided path is "".[ The timing of this isn't wonderful, but applying this now before we
have statx() in any released kernel, before anybody starts using the
NULL special case. - Linus ]Fixes: a528d35e8bfc ("statx: Add a system call to make enhanced file info available")
Reported-by: Michael Kerrisk
Signed-off-by: David Howells
cc: Eric Sandeen
cc: fstests@vger.kernel.org
cc: linux-api@vger.kernel.org
cc: linux-man@vger.kernel.org
Signed-off-by: Linus Torvalds
18 Apr, 2017
1 commit
-
Signed-off-by: Al Viro
03 Apr, 2017
5 commits
-
Include a mask in struct stat to indicate which bits of stx_attributes the
filesystem actually supports.This would also be useful if we add another system call that allows you to
do a 'bulk attribute set' and pass in a statx struct with the masks
appropriately set to say what you want to set.Signed-off-by: David Howells
Signed-off-by: Al Viro -
Reserve the top bit of the mask for future expansion of the statx struct
and give an error if statx() sees it set. All the other bits are ignored
if we see them set but don't support the bit; we just clear the bit in the
returned mask.Signed-off-by: David Howells
Signed-off-by: Al Viro -
I found that statx() was significantly slower than stat(). As a
microbenchmark, I compared 10,000,000 invocations of fstat() on a tmpfs
file to the same with statx() passed a NULL path:$ time ./stat_benchmark
real 0m1.464s
user 0m0.275s
sys 0m1.187s$ time ./statx_benchmark
real 0m5.530s
user 0m0.281s
sys 0m5.247sstatx is expected to be a little slower than stat because struct statx
is larger than struct stat, but not by *that* much. It turns out that
most of the overhead was in copying struct statx to userspace, mostly in
all the stac/clac instructions that got generated for each __put_user()
call. (This was on x86_64, but some other architectures, e.g. arm64,
have something similar now too.)stat() instead initializes its struct on the stack and copies it to
userspace with a single call to copy_to_user(). This turns out to be
much faster, and changing statx to do this makes it almost as fast as
stat:$ time ./statx_benchmark
real 0m1.624s
user 0m0.270s
sys 0m1.354sFor zeroing the reserved fields, start by zeroing the full struct with
memset. This makes it clear that every byte copied to userspace is
initialized, even implicit padding bytes (though there are none
currently). In the scenarios I tested, it also performed the same as a
designated initializer. Manually initializing each field was still
slightly faster, but would have been more error-prone and less
verifiable.Also rename statx_set_result() to cp_statx() for consistency with
cp_old_stat() et al., and make it noinline so that struct statx doesn't
add to the stack usage during the main portion of the syscall execution.Signed-off-by: Eric Biggers
Signed-off-by: David Howells
Signed-off-by: Al Viro -
request_mask and query_flags are function arguments, not passed in
struct kstat. So remove the part of the comment which claims otherwise.
This was apparently left over from an earlier version of the statx
patch.Signed-off-by: Eric Biggers
Signed-off-by: David Howells
Reviewed-by: Christoph Hellwig
Signed-off-by: Al Viro -
The statx() system call currently accepts unknown flags when called with
a NULL path to operate on a file descriptor. Left unchanged, this could
make it hard to introduce new query flags in the future, since
applications may not be able to tell whether a given flag is supported.Fix this by failing the system call with EINVAL if any flags other than
KSTAT_QUERY_FLAGS are specified in combination with a NULL path.Arguably, we could still permit known lookup-related flags such as
AT_SYMLINK_NOFOLLOW. However, that would be inconsistent with how
sys_utimensat() behaves when passed a NULL path, which seems to be the
closest precedent. And given that the NULL path case is (I believe)
mainly intended to be used to implement a wrapper function like fstatx()
that doesn't have a path argument, I think rejecting lookup-related
flags too is probably the best choice.Signed-off-by: Eric Biggers
Signed-off-by: David Howells
Signed-off-by: Al Viro
04 Mar, 2017
1 commit
-
Pull vfs 'statx()' update from Al Viro.
This adds the new extended stat() interface that internally subsumes our
previous stat interfaces, and allows user mode to specify in more detail
what kind of information it wants.It also allows for some explicit synchronization information to be
passed to the filesystem, which can be relevant for network filesystems:
is the cached value ok, or do you need open/close consistency, or what?From David Howells.
Andreas Dilger points out that the first version of the extended statx
interface was posted June 29, 2010:https://www.spinics.net/lists/linux-fsdevel/msg33831.html
* 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
statx: Add a system call to make enhanced file info available
03 Mar, 2017
1 commit
-
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 & S_IFMT
STATX_MODE Want/got stx_mode & ~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 fsWithin 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+0000Signed-off-by: David Howells
Signed-off-by: Al Viro
02 Mar, 2017
1 commit
-
Add #include dependencies to all .c files rely on sched.h
doing that for them.Note that even if the count where we need to add extra headers seems high,
it's still a net win, because is included in over
2,200 files ...Acked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
28 Feb, 2017
1 commit
-
Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.[geliangtang@gmail.com: truncate: use i_blocksize()]
Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick
Signed-off-by: Geliang Tang
Cc: Alexander Viro
Cc: Ross Zwisler
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Dec, 2016
1 commit
-
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
sed -i -e "s!$PATT!#include !" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)to do the replacement at the end of the merge window.
Requested-by: Al Viro
Signed-off-by: Linus Torvalds
09 Dec, 2016
1 commit
-
Also check d_is_symlink() in callers instead of inode->i_op->readlink
because following patches will allow NULL ->readlink for symlinks.Signed-off-by: Miklos Szeredi
17 Jan, 2016
1 commit
-
New_valid_dev() always returns true, so that's unnecessary to perform
new_valid_dev() checks in some filesystems. Most checks of
new_valid_dev() have been removed so let's drop this last one and then
we can remove new_valid_dev() from the source code.No functional change.
Signed-off-by: Yaowei Bai
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Nov, 2015
1 commit
-
new_valid_dev() always returns 1, so the !new_valid_dev() check is not
needed. Remove it.Signed-off-by: Yaowei Bai
Cc: Alexander Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Apr, 2015
1 commit
-
Signed-off-by: David Howells
Signed-off-by: Al Viro
12 Apr, 2015
1 commit
-
Signed-off-by: Al Viro
09 Nov, 2013
1 commit
-
The filehandle lookup code wants this version of getattr.
Reviewed-by: Christoph Hellwig
Signed-off-by: J. Bruce Fields
Signed-off-by: Al Viro
