Commit Graph

269 Commits

Author SHA1 Message Date
Vivek Goyal 519525fa47 fuse: Support RENAME_WHITEOUT flag
Allow fuse to pass RENAME_WHITEOUT to fuse server.  Overlayfs on top of
virtiofs uses RENAME_WHITEOUT.

Without this patch renaming a directory in overlayfs (dir is on lower)
fails with -EINVAL. With this patch it works.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-02-06 16:39:28 +01:00
Miklos Szeredi c634da718d fuse: verify nlink
When adding a new hard link, make sure that i_nlink doesn't overflow.

Fixes: ac45d61357 ("fuse: fix nlink after unlink")
Cc: <stable@vger.kernel.org> # v3.4
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-11-12 11:49:04 +01:00
Miklos Szeredi eb59bd17d2 fuse: verify attributes
If a filesystem returns negative inode sizes, future reads on the file were
causing the cpu to spin on truncate_pagecache.

Create a helper to validate the attributes.  This now does two things:

 - check the file mode
 - check if the file size fits in i_size without overflowing

Reported-by: Arijit Banerjee <arijit@rubrik.com>
Fixes: d8a5ba4545 ("[PATCH] FUSE - core")
Cc: <stable@vger.kernel.org> # v2.6.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-11-12 11:49:04 +01:00
Miklos Szeredi b24e7598db fuse: flush dirty data/metadata before non-truncate setattr
If writeback cache is enabled, then writes might get reordered with
chmod/chown/utimes.  The problem with this is that performing the write in
the fuse daemon might itself change some of these attributes.  In such case
the following sequence of operations will result in file ending up with the
wrong mode, for example:

  int fd = open ("suid", O_WRONLY|O_CREAT|O_EXCL);
  write (fd, "1", 1);
  fchown (fd, 0, 0);
  fchmod (fd, 04755);
  close (fd);

This patch fixes this by flushing pending writes before performing
chown/chmod/utimes.

Reported-by: Giuseppe Scrivano <gscrivan@redhat.com>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Fixes: 4d99ff8f12 ("fuse: Turn writeback cache on")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-10-23 14:26:37 +02:00
Miklos Szeredi 6c26f71759 fuse: don't advise readdirplus for negative lookup
If the FUSE_READDIRPLUS_AUTO feature is enabled, then lookups on a
directory before/during readdir are used as an indication that READDIRPLUS
should be used instead of READDIR.  However if the lookup turns out to be
negative, then selecting READDIRPLUS makes no sense.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-10-21 15:57:07 +02:00
Khazhismel Kumykov dc69e98c24 fuse: kmemcg account fs data
account per-file, dentry, and inode data

blockdev/superblock and temporary per-request data was left alone, as
this usually isn't accounted

Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-24 15:28:01 +02:00
Khazhismel Kumykov 30c6a23d34 fuse: on 64-bit store time in d_fsdata directly
Implements the optimization noted in commit f75fdf22b0 ("fuse: don't
use ->d_time"), as the additional memory can be significant.  (In
particular, on SLAB configurations this 8-byte alloc becomes 32 bytes).
Per-dentry, this can consume significant memory.

Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-24 15:28:01 +02:00
Miklos Szeredi 8fab010644 fuse: delete dentry if timeout is zero
Don't hold onto dentry in lru list if need to re-lookup it anyway at next
access.  Only do this if explicitly enabled, otherwise it could result in
performance regression.

More advanced version of this patch would periodically flush out dentries
from the lru which have gone stale.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-12 14:59:41 +02:00
Miklos Szeredi 4c29afece8 fuse: convert readlink to simple api
Also turn BUG_ON into gracefully recovered WARN_ON.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10 16:29:49 +02:00
Miklos Szeredi d5b4854357 fuse: flatten 'struct fuse_args'
...to make future expansion simpler.  The hiearachical structure is a
historical thing that does not serve any practical purpose.

The generated code is excatly the same before and after the patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-10 16:29:48 +02:00
Kirill Tkhai c9d8f5f069 fuse: Protect fi->nlookup with fi->lock
This continues previous patch and introduces the same protection for
nlookup field.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13 13:15:14 +01:00
Kirill Tkhai f15ecfef05 fuse: Introduce fi->lock to protect write related fields
To minimize contention of fc->lock, this patch introduces a new spinlock
for protection fuse_inode metadata:

fuse_inode:
	writectr
	writepages
	write_files
	queued_writes
	attr_version

inode:
	i_size
	i_nlink
	i_mtime
	i_ctime

Also, it protects the fields changed in fuse_change_attributes_common()
(too many to list).

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13 13:15:14 +01:00
Kirill Tkhai 4510d86fbb fuse: Convert fc->attr_version into atomic64_t
This patch makes fc->attr_version of atomic64_t type, so fc->lock won't be
needed to read or modify it anymore.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13 13:15:13 +01:00
Kirill Tkhai ebf84d0c72 fuse: Add fuse_inode argument to fuse_prepare_release()
Here is preparation for next patches, which introduce new fi->lock for
protection of ff->write_entry linked into fi->write_files.

This patch just passes new argument to the function.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-13 13:15:13 +01:00
Chad Austin 2e64ff154c fuse: continue to send FUSE_RELEASEDIR when FUSE_OPEN returns ENOSYS
When FUSE_OPEN returns ENOSYS, the no_open bit is set on the connection.

Because the FUSE_RELEASE and FUSE_RELEASEDIR paths share code, this
incorrectly caused the FUSE_RELEASEDIR request to be dropped and never sent
to userspace.

Pass an isdir bool to distinguish between FUSE_RELEASE and FUSE_RELEASEDIR
inside of fuse_file_put.

Fixes: 7678ac5061 ("fuse: support clients that don't implement 'open'")
Cc: <stable@vger.kernel.org> # v3.14
Signed-off-by: Chad Austin <chadaustin@fb.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-12-11 21:47:28 +01:00
Miklos Szeredi d233c7dd16 fuse: fix revalidation of attributes for permission check
fuse_invalidate_attr() now sets fi->inval_mask instead of fi->i_time, hence
we need to check the inval mask in fuse_permission() as well.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 2f1e81965f ("fuse: allow fine grained attr cache invaldation")
2018-12-03 10:14:43 +01:00
Miklos Szeredi a9c2d1e82f fuse: fix fsync on directory
Commit ab2257e994 ("fuse: reduce size of struct fuse_inode") moved parts
of fields related to writeback on regular file and to directory caching
into a union.  However fuse_fsync_common() called from fuse_dir_fsync()
touches some writeback related fields, resulting in a crash.

Move writeback related parts from fuse_fsync_common() to fuse_fysnc().

Reported-by: Brett Girton <btgirton@gmail.com>
Tested-by: Brett Girton <btgirton@gmail.com>
Fixes: ab2257e994 ("fuse: reduce size of struct fuse_inode")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-12-03 10:14:43 +01:00
Dan Schatzberg 5571f1e654 fuse: enable caching of symlinks
FUSE file reads are cached in the page cache, but symlink reads are
not. This patch enables FUSE READLINK operations to be cached which
can improve performance of some FUSE workloads.

In particular, I'm working on a FUSE filesystem for access to source
code and discovered that about a 10% improvement to build times is
achieved with this patch (there are a lot of symlinks in the source
tree).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-15 15:43:07 +02:00
Miklos Szeredi 802dc0497b fuse: don't need GETATTR after every READ
If 'auto_inval_data' mode is active, then fuse_file_read_iter() will call
fuse_update_attributes(), which will check the attribute validity and send
a GETATTR request if some of the attributes are no longer valid.  The page
cache is then invalidated if the size or mtime have changed.

Then, if a READ request was sent and reply received (which is the case if
the data wasn't cached yet, or if the file is opened for O_DIRECT), the
atime attribute is invalidated.

This will result in the next read() also triggering a GETATTR, ...

This can be fixed by only sending GETATTR if the mode or size are invalid,
we don't need to do a refresh if only atime is invalid.

More generally, none of the callers of fuse_update_attributes() need an
up-to-date atime value, so for now just remove STATX_ATIME from the request
mask when attributes are updated for internal use.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-15 15:43:06 +02:00
Miklos Szeredi 2f1e81965f fuse: allow fine grained attr cache invaldation
This patch adds the infrastructure for more fine grained attribute
invalidation.  Currently only 'atime' is invalidated separately.

The use of this infrastructure is extended to the statx(2) interface, which
for now means that if only 'atime' is invalid and STATX_ATIME is not
specified in the mask argument, then no GETATTR request will be generated.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-15 15:43:06 +02:00
Miklos Szeredi ab2257e994 fuse: reduce size of struct fuse_inode
Do this by grouping fields used for cached writes and putting them into a
union with fileds used for cached readdir (with obviously no overlap, since
we don't have hybrid objects).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01 10:07:05 +02:00
Miklos Szeredi 261aaba72f fuse: use iversion for readdir cache verification
Use the internal iversion counter to make sure modifications of the
directory through this filesystem are not missed by the mtime check (due to
mtime granularity).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01 10:07:05 +02:00
Miklos Szeredi d123d8e183 fuse: split out readdir.c
Directory reading code is about to grow larger, so split it out from dir.c
into a new source file.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-28 16:43:23 +02:00
Linus Torvalds ad1d697358 fuse update for 4.19
This contains various bug fixes and cleanups.
 -----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCW3xvGwAKCRDh3BK/laaZ
 PKECAP9qUpdtQ5RaIL/y9OGZzJLSZbBZuK3LGNY2u2B3EfrSjgEAvhkhXyOQgvVi
 kgYLNszbg/C+w8U4Xc5GWB6cjNm6rwE=
 =GJI7
 -----END PGP SIGNATURE-----

Merge tag 'fuse-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse update from Miklos Szeredi:
 "Various bug fixes and cleanups"

* tag 'fuse-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: reduce allocation size for splice_write
  fuse: use kvmalloc to allocate array of pipe_buffer structs.
  fuse: convert last timespec use to timespec64
  fs: fuse: Adding new return type vm_fault_t
  fuse: simplify fuse_abort_conn()
  fuse: Add missed unlock_page() to fuse_readpages_fill()
  fuse: Don't access pipe->buffers without pipe_lock()
  fuse: fix initial parallel dirops
  fuse: Fix oops at process_init_reply()
  fuse: umount should wait for all requests
  fuse: fix unlocked access to processing queue
  fuse: fix double request_end()
2018-08-21 18:47:36 -07:00
Linus Torvalds 0ea97a2d61 Merge branch 'work.mkdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs icache updates from Al Viro:

 - NFS mkdir/open_by_handle race fix

 - analogous solution for FUSE, replacing the one currently in mainline

 - new primitive to be used when discarding halfway set up inodes on
   failed object creation; gives sane warranties re icache lookups not
   returning such doomed by still not freed inodes. A bunch of
   filesystems switched to that animal.

 - Miklos' fix for last cycle regression in iget5_locked(); -stable will
   need a slightly different variant, unfortunately.

 - misc bits and pieces around things icache-related (in adfs and jfs).

* 'work.mkdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  jfs: don't bother with make_bad_inode() in ialloc()
  adfs: don't put inodes into icache
  new helper: inode_fake_hash()
  vfs: don't evict uninitialized inode
  jfs: switch to discard_new_inode()
  ext2: make sure that partially set up inodes won't be returned by ext2_iget()
  udf: switch to discard_new_inode()
  ufs: switch to discard_new_inode()
  btrfs: switch to discard_new_inode()
  new primitive: discard_new_inode()
  kill d_instantiate_no_diralias()
  nfs_instantiate(): prevent multiple aliases for directory inode
2018-08-13 20:25:58 -07:00
Al Viro c971e6a006 kill d_instantiate_no_diralias()
The only user is fuse_create_new_entry(), and there it's used to
mitigate the same mkdir/open-by-handle race as in nfs_mkdir().
The same solution applies - unhash the mkdir argument, then
call d_splice_alias() and if that returns a reference to preexisting
alias, dput() and report success.  ->mkdir() argument left unhashed
negative with the preexisting alias moved in the right place is just
fine from the ->mkdir() callers point of view.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-08-01 23:18:53 -04:00
Miklos Szeredi 63576c13bd fuse: fix initial parallel dirops
If parallel dirops are enabled in FUSE_INIT reply, then first operation may
leave fi->mutex held.

Reported-by: syzbot <syzbot+3f7b29af1baa9d0a55be@syzkaller.appspotmail.com>
Fixes: 5c672ab3f0 ("fuse: serialize dirops by default")
Cc: <stable@vger.kernel.org> # v4.7
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-07-26 16:13:11 +02:00
Al Viro 44907d7900 get rid of 'opened' argument of ->atomic_open() - part 3
now it can be done...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:20 -04:00
Al Viro b452a458ca getting rid of 'opened' argument of ->atomic_open() - part 2
__gfs2_lookup(), gfs2_create_inode(), nfs_finish_open() and fuse_create_open()
don't need 'opened' anymore.  Get rid of that argument in those.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:20 -04:00
Al Viro be12af3ef5 getting rid of 'opened' argument of ->atomic_open() - part 1
'opened' argument of finish_open() is unused.  Kill it.

Signed-off-by Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:19 -04:00
Al Viro 73a09dd943 introduce FMODE_CREATED and switch to it
Parallel to FILE_CREATED, goes into ->f_mode instead of *opened.
NFS is a bit of a wart here - it doesn't have file at the point
where FILE_CREATED used to be set, so we need to propagate it
there (for now).  IMA is another one (here and everywhere)...

Note that this needs do_dentry_open() to leave old bits in ->f_mode
alone - we want it to preserve FMODE_CREATED if it had been already
set (no other bit can be there).

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-07-12 10:04:18 -04:00
Miklos Szeredi bf5c1898bf fuse: honor AT_STATX_FORCE_SYNC
Force a refresh of attributes from the fuse server in this case.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20 17:11:44 +01:00
Miklos Szeredi ff1b89f389 fuse: honor AT_STATX_DONT_SYNC
The description of this flag says "Don't sync attributes with the server".
In other words: always use the attributes cached in the kernel and don't
send network or local messages to refresh the attributes.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20 17:11:44 +01:00
Seth Forshee 73f03c2b4b fuse: Restrict allow_other to the superblock's namespace or a descendant
Unprivileged users are normally restricted from mounting with the
allow_other option by system policy, but this could be bypassed for a mount
done with user namespace root permissions. In such cases allow_other should
not allow users outside the userns to access the mount as doing so would
give the unprivileged user the ability to manipulate processes it would
otherwise be unable to manipulate. Restrict allow_other to apply to users
in the same userns used at mount or a descendant of that namespace. Also
export current_in_userns() for use by fuse when built as a module.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Dongsu Park <dongsu@kinvolk.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20 17:11:44 +01:00
Eric W. Biederman 8cb08329b0 fuse: Support fuse filesystems outside of init_user_ns
In order to support mounts from namespaces other than init_user_ns, fuse
must translate uids and gids to/from the userns of the process servicing
requests on /dev/fuse. This patch does that, with a couple of restrictions
on the namespace:

 - The userns for the fuse connection is fixed to the namespace
   from which /dev/fuse is opened.

 - The namespace must be the same as s_user_ns.

These restrictions simplify the implementation by avoiding the need to pass
around userns references and by allowing fuse to rely on the checks in
setattr_prepare for ownership changes.  Either restriction could be relaxed
in the future if needed.

For cuse the userns used is the opener of /dev/cuse.  Semantically the cuse
support does not appear safe for unprivileged users.  Practically the
permissions on /dev/cuse only make it accessible to the global root user.
If something slips through the cracks in a user namespace the only users
who will be able to use the cuse device are those users mapped into the
user namespace.

Translation in the posix acl is updated to use the uuser namespace of the
filesystem.  Avoiding cases which might bypass this translation is handled
in a following change.

This change is stronlgy based on a similar change from Seth Forshee and
Dongsu Park.

Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Dongsu Park <dongsu@kinvolk.io>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-03-20 17:11:44 +01:00
Miklos Szeredi df0e91d488 fuse: atomic_o_trunc should truncate pagecache
Fuse has an "atomic_o_trunc" mode, where userspace filesystem uses the
O_TRUNC flag in the OPEN request to truncate the file atomically with the
open.

In this mode there's no need to send a SETATTR request to userspace after
the open, so fuse_do_setattr() checks this mode and returns.  But this
misses the important step of truncating the pagecache.

Add the missing parts of truncation to the ATTR_OPEN branch.

Reported-by: Chad Austin <chadaustin@fb.com>
Fixes: 6ff958edbf ("fuse: add atomic open+truncate support")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
2018-03-20 17:11:43 +01:00
Miklos Szeredi c6cdd51404 fuse: fix READDIRPLUS skipping an entry
Marios Titas running a Haskell program noticed a problem with fuse's
readdirplus: when it is interrupted by a signal, it skips one directory
entry.

The reason is that fuse erronously updates ctx->pos after a failed
dir_emit().

The issue originates from the patch adding readdirplus support.

Reported-by: Jakob Unterwurzacher <jakobunt@gmail.com>
Tested-by: Marios Titas <redneb@gmx.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 0b05b18381 ("fuse: implement NFS-like readdirplus support")
Cc: <stable@vger.kernel.org> # v3.9
2017-10-25 16:34:27 +02:00
Miklos Szeredi 5b97eeacbd fuse: getattr cleanup
The refreshed argument isn't used by any caller, get rid of it.

Use a helper for just updating the inode (no need to fill in a kstat).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-09-12 16:57:54 +02:00
Linus Torvalds 4e66c42c60 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse update from Miklos Szeredi:
 "A bugfix and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: release: private_data cannot be NULL
  fuse: cleanup fuse_file refcounting
  fuse: add missing FR_FORCE
2017-03-03 12:14:13 -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
Miklos Szeredi 267d84449f fuse: cleanup fuse_file refcounting
struct fuse_file is stored in file->private_data.  Make this always be a
counting reference for consistency.

This also allows fuse_sync_release() to call fuse_file_put() instead of
partially duplicating its functionality.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-22 20:08:25 +01:00
David Sheets 210675270c fuse: fix time_to_jiffies nsec sanity check
Commit bcb6f6d2b9 ("fuse: use timespec64") introduced clamped nsec values
in time_to_jiffies but used the max of nsec and NSEC_PER_SEC - 1 instead of
the min. Because of this, dentries would stay in the cache longer than
requested and go stale in scenarios that relied on their timely eviction.

Fixes: bcb6f6d2b9 ("fuse: use timespec64")
Signed-off-by: David Sheets <dsheets@docker.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org> # 4.9
2017-01-13 17:20:47 +01:00
Linus Torvalds 231753ef78 Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull partial readlink cleanups from Miklos Szeredi.

This is the uncontroversial part of the readlink cleanup patch-set that
simplifies the default readlink handling.

Miklos and Al are still discussing the rest of the series.

* git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  vfs: make generic_readlink() static
  vfs: remove ".readlink = generic_readlink" assignments
  vfs: default to generic_readlink()
  vfs: replace calling i_op->readlink with vfs_readlink()
  proc/self: use generic_readlink
  ecryptfs: use vfs_get_link()
  bad_inode: add missing i_op initializers
2016-12-17 19:16:12 -08:00
Miklos Szeredi dfeef68862 vfs: remove ".readlink = generic_readlink" assignments
If .readlink == NULL implies generic_readlink().

Generated by:

to_del="\.readlink.*=.*generic_readlink"
for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-09 16:45:04 +01:00
Miklos Szeredi c01638f5d9 fuse: fix clearing suid, sgid for chown()
Basically, the pjdfstests set the ownership of a file to 06555, and then
chowns it (as root) to a new uid/gid. Prior to commit a09f99edde ("fuse:
fix killing s[ug]id in setattr"), fuse would send down a setattr with both
the uid/gid change and a new mode.  Now, it just sends down the uid/gid
change.

Technically this is NOTABUG, since POSIX doesn't _require_ that we clear
these bits for a privileged process, but Linux (wisely) has done that and I
think we don't want to change that behavior here.

This is caused by the use of should_remove_suid(), which will always return
0 when the process has CAP_FSETID.

In fact we really don't need to be calling should_remove_suid() at all,
since we've already been indicated that we should remove the suid, we just
don't want to use a (very) stale mode for that.

This patch should fix the above as well as simplify the logic.

Reported-by: Jeff Layton <jlayton@redhat.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: a09f99edde ("fuse: fix killing s[ug]id in setattr")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
2016-12-06 16:18:45 +01:00
Miklos Szeredi 0ce267ff95 fuse: fix root dentry initialization
Add missing dentry initialization to root dentry.

Fixes: f75fdf22b0 ("fuse: don't use ->d_time")
Reported-by: Andreas Reis <andreas.reis@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-18 15:36:48 +02:00
Linus Torvalds 101105b171 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
 ">rename2() work from Miklos + current_time() from Deepa"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: Replace current_fs_time() with current_time()
  fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
  fs: Replace CURRENT_TIME with current_time() for inode timestamps
  fs: proc: Delete inode time initializations in proc_alloc_inode()
  vfs: Add current_time() api
  vfs: add note about i_op->rename changes to porting
  fs: rename "rename2" i_op to "rename"
  vfs: remove unused i_op->rename
  fs: make remaining filesystems use .rename2
  libfs: support RENAME_NOREPLACE in simple_rename()
  fs: support RENAME_NOREPLACE for local filesystems
  ncpfs: fix unused variable warning
2016-10-10 20:16:43 -07:00
Al Viro 3873691e5a Merge remote-tracking branch 'ovl/rename2' into for-linus 2016-10-10 23:02:51 -04:00
Linus Torvalds 97d2116708 Merge branch 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs xattr updates from Al Viro:
 "xattr stuff from Andreas

  This completes the switch to xattr_handler ->get()/->set() from
  ->getxattr/->setxattr/->removexattr"

* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: Remove {get,set,remove}xattr inode operations
  xattr: Stop calling {get,set,remove}xattr inode operations
  vfs: Check for the IOP_XATTR flag in listxattr
  xattr: Add __vfs_{get,set,remove}xattr helpers
  libfs: Use IOP_XATTR flag for empty directory handling
  vfs: Use IOP_XATTR flag for bad-inode handling
  vfs: Add IOP_XATTR inode operations flag
  vfs: Move xattr_resolve_name to the front of fs/xattr.c
  ecryptfs: Switch to generic xattr handlers
  sockfs: Get rid of getxattr iop
  sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
  kernfs: Switch to generic xattr handlers
  hfs: Switch to generic xattr handlers
  jffs2: Remove jffs2_{get,set,remove}xattr macros
  xattr: Remove unnecessary NULL attribute name check
2016-10-10 17:11:50 -07:00
Linus Torvalds abb5a14fa2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted misc bits and pieces.

  There are several single-topic branches left after this (rename2
  series from Miklos, current_time series from Deepa Dinamani, xattr
  series from Andreas, uaccess stuff from from me) and I'd prefer to
  send those separately"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
  proc: switch auxv to use of __mem_open()
  hpfs: support FIEMAP
  cifs: get rid of unused arguments of CIFSSMBWrite()
  posix_acl: uapi header split
  posix_acl: xattr representation cleanups
  fs/aio.c: eliminate redundant loads in put_aio_ring_file
  fs/internal.h: add const to ns_dentry_operations declaration
  compat: remove compat_printk()
  fs/buffer.c: make __getblk_slow() static
  proc: unsigned file descriptors
  fs/file: more unsigned file descriptors
  fs: compat: remove redundant check of nr_segs
  cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
  cifs: don't use memcpy() to copy struct iov_iter
  get rid of separate multipage fault-in primitives
  fs: Avoid premature clearing of capabilities
  fs: Give dentry to inode_change_ok() instead of inode
  fuse: Propagate dentry down to inode_change_ok()
  ceph: Propagate dentry down to inode_change_ok()
  xfs: Propagate dentry down to inode_change_ok()
  ...
2016-10-10 13:04:49 -07:00