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
...
The io_uring interfaces have been replaced by do_statx() and are no
longer needed.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is a prepatory patch to allow io_uring to invoke statx directly.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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 <mzxreary@0pointer.de>
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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 <mszeredi@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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 <dhowells@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-man@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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 <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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 <axboe@kernel.dk>
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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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 <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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 <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <jack@suse.cz>
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()
The change in commit 1e2f82d1e9 ("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 <mtk.manpages@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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: a528d35e8b ("statx: Add a system call to make enhanced file info available")
Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Sandeen <sandeen@sandeen.net>
cc: fstests@vger.kernel.org
cc: linux-api@vger.kernel.org
cc: linux-man@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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 <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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 0m5.247s
statx 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 0m1.354s
For 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 <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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 <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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 <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
