Commit Graph

100 Commits

Author SHA1 Message Date
Linus Torvalds 05e6295f7b fs.idmapped.v6.3
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Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...
2023-02-20 11:53:11 -08:00
Jeff Layton a1175d6b1b vfs: plumb i_version handling into struct kstat
The NFS server has a lot of special handling for different types of
change attribute access, depending on the underlying filesystem. In
most cases, it's doing a getattr anyway and then fetching that value
after the fact.

Rather that do that, add a new STATX_CHANGE_COOKIE flag that is a
kernel-only symbol (for now). If requested and getattr can implement it,
it can fill out this field. For IS_I_VERSION inodes, add a generic
implementation in vfs_getattr_nosec. Take care to mask
STATX_CHANGE_COOKIE off in requests from userland and in the result
mask.

Since not all filesystems can give the same guarantees of monotonicity,
claim a STATX_ATTR_CHANGE_MONOTONIC flag that filesystems can set to
indicate that they offer an i_version value that can never go backward.

Eventually if we decide to make the i_version available to userland, we
can just designate a field for it in struct statx, and move the
STATX_CHANGE_COOKIE definition to the uapi header.

Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2023-01-26 07:00:06 -05:00
Christian Brauner e67fe63341
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:29 +01:00
Christian Brauner b74d24f7a7
fs: port ->getattr() to pass mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:25 +01:00
Christian Brauner a2bd096fb2
fs: use type safe idmapping helpers
We already ported most parts and filesystems over for v6.0 to the new
vfs{g,u}id_t type and associated helpers for v6.0. Convert the remaining
places so we can remove all the old helpers.
This is a non-functional change.

Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-26 10:02:34 +02:00
Eric Biggers 2d985f8c6b vfs: support STATX_DIOALIGN on block devices
Add support for STATX_DIOALIGN to block devices, so that direct I/O
alignment restrictions are exposed to userspace in a generic way.

Note that this breaks the tradition of stat operating only on the block
device node, not the block device itself.  However, it was felt that
doing this is preferable, in order to make the interface useful and
avoid needing separate interfaces for regular files and block devices.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/r/20220827065851.135710-3-ebiggers@kernel.org
2022-09-11 19:47:12 -05:00
Eric Biggers 825cf206ed statx: add direct I/O alignment information
Traditionally, the conditions for when DIO (direct I/O) is supported
were fairly simple.  For both block devices and regular files, DIO had
to be aligned to the logical block size of the block device.

However, due to filesystem features that have been added over time (e.g.
multi-device support, data journalling, inline data, encryption, verity,
compression, checkpoint disabling, log-structured mode), the conditions
for when DIO is allowed on a regular file have gotten increasingly
complex.  Whether a particular regular file supports DIO, and with what
alignment, can depend on various file attributes and filesystem mount
options, as well as which block device(s) the file's data is located on.

Moreover, the general rule of DIO needing to be aligned to the block
device's logical block size was recently relaxed to allow user buffers
(but not file offsets) aligned to the DMA alignment instead.  See
commit bf8d08532b ("iomap: add support for dma aligned direct-io").

XFS has an ioctl XFS_IOC_DIOINFO that exposes DIO alignment information.
Uplifting this to the VFS is one possibility.  However, as discussed
(https://lore.kernel.org/linux-fsdevel/20220120071215.123274-1-ebiggers@kernel.org/T/#u),
this ioctl is rarely used and not known to be used outside of
XFS-specific code.  It was also never intended to indicate when a file
doesn't support DIO at all, nor was it intended for block devices.

Therefore, let's expose this information via statx().  Add the
STATX_DIOALIGN flag and two new statx fields associated with it:

* stx_dio_mem_align: the alignment (in bytes) required for user memory
  buffers for DIO, or 0 if DIO is not supported on the file.

* stx_dio_offset_align: the alignment (in bytes) required for file
  offsets and I/O segment lengths for DIO, or 0 if DIO is not supported
  on the file.  This will only be nonzero if stx_dio_mem_align is
  nonzero, and vice versa.

Note that as with other statx() extensions, if STATX_DIOALIGN isn't set
in the returned statx struct, then these new fields won't be filled in.
This will happen if the file is neither a regular file nor a block
device, or if the file is a regular file and the filesystem doesn't
support STATX_DIOALIGN.  It might also happen if the caller didn't
include STATX_DIOALIGN in the request mask, since statx() isn't required
to return unrequested information.

This commit only adds the VFS-level plumbing for STATX_DIOALIGN.  For
regular files, individual filesystems will still need to add code to
support it.  For block devices, a separate commit will wire it up too.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20220827065851.135710-2-ebiggers@kernel.org
2022-09-11 19:47:04 -05:00
Linus Torvalds 35b51afd23 RISC-V Patches for the 5.19 Merge Window, Part 1
* Support for the Svpbmt extension, which allows memory attributes to be
   encoded in pages.
 * Support for the Allwinner D1's implementation of page-based memory
   attributes.
 * Support for running rv32 binaries on rv64 systems, via the compat
   subsystem.
 * Support for kexec_file().
 * Support for the new generic ticket-based spinlocks, which allows us to
   also move to qrwlock.  These should have already gone in through the
   asm-geneic tree as well.
 * A handful of cleanups and fixes, include some larger ones around
   atomics and XIP.
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Merge tag 'riscv-for-linus-5.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for the Svpbmt extension, which allows memory attributes to
   be encoded in pages

 - Support for the Allwinner D1's implementation of page-based memory
   attributes

 - Support for running rv32 binaries on rv64 systems, via the compat
   subsystem

 - Support for kexec_file()

 - Support for the new generic ticket-based spinlocks, which allows us
   to also move to qrwlock. These should have already gone in through
   the asm-geneic tree as well

 - A handful of cleanups and fixes, include some larger ones around
   atomics and XIP

* tag 'riscv-for-linus-5.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (51 commits)
  RISC-V: Prepare dropping week attribute from arch_kexec_apply_relocations[_add]
  riscv: compat: Using seperated vdso_maps for compat_vdso_info
  RISC-V: Fix the XIP build
  RISC-V: Split out the XIP fixups into their own file
  RISC-V: ignore xipImage
  RISC-V: Avoid empty create_*_mapping definitions
  riscv: Don't output a bogus mmu-type on a no MMU kernel
  riscv: atomic: Add custom conditional atomic operation implementation
  riscv: atomic: Optimize dec_if_positive functions
  riscv: atomic: Cleanup unnecessary definition
  RISC-V: Load purgatory in kexec_file
  RISC-V: Add purgatory
  RISC-V: Support for kexec_file on panic
  RISC-V: Add kexec_file support
  RISC-V: use memcpy for kexec_file mode
  kexec_file: Fix kexec_file.c build error for riscv platform
  riscv: compat: Add COMPAT Kbuild skeletal support
  riscv: compat: ptrace: Add compat_arch_ptrace implement
  riscv: compat: signal: Add rt_frame implementation
  riscv: add memory-type errata for T-Head
  ...
2022-05-31 14:10:54 -07:00
Guo Ren f18ed30db2
fs: stat: compat: Add __ARCH_WANT_COMPAT_STAT
RISC-V doesn't neeed compat_stat, so using __ARCH_WANT_COMPAT_STAT
to exclude unnecessary SYSCALL functions.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Helge Deller <deller@gmx.de>  # parisc
Link: https://lore.kernel.org/r/20220405071314.3225832-6-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-04-26 13:35:45 -07:00
Mikulas Patocka 932aba1e16 stat: fix inconsistency between struct stat and struct compat_stat
struct stat (defined in arch/x86/include/uapi/asm/stat.h) has 32-bit
st_dev and st_rdev; struct compat_stat (defined in
arch/x86/include/asm/compat.h) has 16-bit st_dev and st_rdev followed by
a 16-bit padding.

This patch fixes struct compat_stat to match struct stat.

[ Historical note: the old x86 'struct stat' did have that 16-bit field
  that the compat layer had kept around, but it was changes back in 2003
  by "struct stat - support larger dev_t":

    https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=e95b2065677fe32512a597a79db94b77b90c968d

  and back in those days, the x86_64 port was still new, and separate
  from the i386 code, and had already picked up the old version with a
  16-bit st_dev field ]

Note that we can't change compat_dev_t because it is used by
compat_loop_info.

Also, if the st_dev and st_rdev values are 32-bit, we don't have to use
old_valid_dev to test if the value fits into them.  This fixes
-EOVERFLOW on filesystems that are on NVMe because NVMe uses the major
number 259.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-04-12 13:35:08 -10:00
Stefan Roesch 1b6fe6e0df io-uring: Make statx API stable
One of the key architectual tenets is to keep the parameters for
io-uring stable. After the call has been submitted, its value can
be changed. Unfortunaltely this is not the case for the current statx
implementation.

IO-Uring change:
This changes replaces the const char * filename pointer in the io_statx
structure with a struct filename *. In addition it also creates the
filename object during the prepare phase.

With this change, the opcode also needs to invoke cleanup, so the
filename object gets freed after processing the request.

fs change:
This replaces the const char* __user filename parameter in the two
functions do_statx and vfs_statx with a struct filename *. In addition
to be able to correctly construct a filename object a new helper
function getname_statx_lookup_flags is introduced. The function makes
sure that do_statx and vfs_statx is invoked with the correct lookup flags.

Signed-off-by: Stefan Roesch <shr@fb.com>
Link: https://lore.kernel.org/r/20220225185326.1373304-2-shr@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-03-10 09:33:55 -07:00
Amir Goldstein 4f911138c8 fs: add generic helper for filling statx attribute flags
The immutable and append-only properties on an inode are published on
the inode's i_flags and enforced by the VFS.

Create a helper to fill the corresponding STATX_ATTR_ flags in the kstat
structure from the inode's i_flags.

Only orange was converted to use this helper.
Other filesystems could use it in the future.

Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-17 11:47:43 +02:00
Theodore Ts'o 5afa7e8b70 fs: fix reporting supported extra file attributes for statx()
statx(2) notes that any attribute that is not indicated as supported
by stx_attributes_mask has no usable value.  Commits 801e523796
("fs: move generic stat response attr handling to vfs_getattr_nosec")
and 712b2698e4 ("fs/stat: Define DAX statx attribute") sets
STATX_ATTR_AUTOMOUNT and STATX_ATTR_DAX, respectively, without setting
stx_attributes_mask, which can cause xfstests generic/532 to fail.

Fix this in the same way as commit 1b9598c8fb ("xfs: fix reporting
supported extra file attributes for statx()")

Fixes: 801e523796 ("fs: move generic stat response attr handling to vfs_getattr_nosec")
Fixes: 712b2698e4 ("fs/stat: Define DAX statx attribute")
Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-04-17 23:03:50 -04:00
Christian Brauner 549c729771
fs: make helpers idmap mount aware
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00
Christian Brauner 0d56a4518d
stat: handle idmapped mounts
The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount map it into the mount's user
namespace before we store the uid and gid. If the initial user namespace
is passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:17 +01:00
Christoph Hellwig f2d077ff1b fs: remove KSTAT_QUERY_FLAGS
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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-26 22:55:05 -04:00
Christoph Hellwig b3f0515004 fs: remove vfs_stat_set_lookup_flags
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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-26 22:55:05 -04:00
Christoph Hellwig 09f1bde401 fs: move vfs_fstatat out of line
This allows to keep vfs_statx static in fs/stat.c to prepare for the following
changes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-26 22:55:05 -04:00
Christoph Hellwig da9aa5d96b fs: remove vfs_statx_fd
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 <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-26 22:55:05 -04:00
Linus Torvalds 96ed320d52 New code for 5.8:
- 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.
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Merge tag 'vfs-5.8-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

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()
2020-06-02 19:45:12 -07:00
Linus Torvalds 1ee08de1e2 for-5.8/io_uring-2020-06-01
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Merge tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block

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
  ...
2020-06-02 15:42:50 -07:00
Bijan Mottahedeh 6f88cc176a statx: hide interfaces no longer used by io_uring
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>
2020-05-26 16:48:06 -06:00
Bijan Mottahedeh 0018784fc8 statx: allow system call to be invoked from io_uring
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>
2020-05-26 16:48:06 -06:00
Miklos Szeredi 80340fe360 statx: add mount_root
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>
2020-05-14 16:44:24 +02:00
Miklos Szeredi fa2fcf4f1d statx: add mount ID
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 <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-14 16:44:24 +02:00
Miklos Szeredi 761e28fa27 statx: don't clear STATX_ATIME on SB_RDONLY
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>
2020-05-14 16:44:24 +02:00
Miklos Szeredi 581701b7ef uapi: deprecate STATX_ALL
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>
2020-05-14 16:44:24 +02:00
Ira Weiny 712b2698e4 fs/stat: Define DAX statx attribute
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>
2020-05-04 08:49:39 -07:00
Jens Axboe 3934e36f60 fs: make two stat prep helpers available
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>
2020-01-20 17:03:54 -07:00
Christoph Hellwig 801e523796 fs: move generic stat response attr handling to vfs_getattr_nosec
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>
2019-02-01 01:55:45 -05:00
Arnd Bergmann 82b355d161 y2038: Remove newstat family from default syscall set
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>
2018-08-29 15:42:20 +02:00
Dominik Brodowski 2dae024806 fs: add do_readlinkat() helper; remove internal call to sys_readlinkat()
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.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
2018-04-02 20:15:34 +02:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
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>
2017-11-02 11:10:55 +01:00
Jan Kara f4a8116a4c fs: Provide __inode_get_bytes()
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>
2017-08-17 22:06:03 +02:00
Al Viro eb315d2ae6 ufs: restore maintaining ->i_blocks
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-09 16:28:01 -04:00
Linus Torvalds 204f144c9f Merge branch 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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()
2017-05-02 11:54:26 -07:00
Michael Kerrisk (man-pages) 59372bbf3a statx: correct error handling of NULL pathname
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>
2017-04-27 10:45:09 -07:00
David Howells 1e2f82d1e9 statx: Kill fd-with-NULL-path support in favour of AT_EMPTY_PATH
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>
2017-04-26 15:05:47 -07:00
Al Viro ac565de31c stat: move compat syscalls from compat.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-17 12:52:25 -04:00
David Howells 3209f68b3c statx: Include a mask for stx_attributes in struct statx
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>
2017-04-03 01:06:00 -04:00
David Howells 47071aee6a statx: Reserve the top bit of the mask for future struct expansion
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>
2017-04-03 01:05:59 -04:00
Eric Biggers 64bd72048a statx: optimize copy of struct statx to userspace
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>
2017-04-03 01:05:57 -04:00
Eric Biggers b15fb70b82 statx: remove incorrect part of vfs_statx() comment
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>
2017-04-03 01:05:57 -04:00
Eric Biggers 8c7493aa3e statx: reject unknown flags when using NULL path
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>
2017-04-03 01:05:56 -04:00
Linus Torvalds 590dce2d49 Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
2017-03-03 11:38:56 -08:00
David Howells a528d35e8b statx: Add a system call to make enhanced file info available
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 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 <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-02 20:51:15 -05:00
Ingo Molnar 5b825c3af1 sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>
Add #include <linux/cred.h> 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 <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:31 +01:00
Fabian Frederick 93407472a2 fs: add i_blocksize()
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 <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:46 -08:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Miklos Szeredi fd4a0edf2a vfs: replace calling i_op->readlink with vfs_readlink()
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 <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00