Ensure the translation happens by failing to read or write
posix acls when the filesystem has not indicated it supports
posix acls.

This ensures that modern cached posix acl support is available
and used when dealing with posix acls.  This is important
because only that path has the code to convernt the uids and
gids in posix acls into the user namespace of a fuse filesystem.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

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: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Currently the userspace has no way of knowing whether the fuse
connection ended because of umount or abort via sysfs. It makes it hard
for filesystems to free the mountpoint after abort without worrying
about removing some new mount.

The patch fixes it by returning different errors when userspace reads
from /dev/fuse (-ENODEV for umount and -ECONNABORTED for abort).

Add a new capability flag FUSE_ABORT_ERROR. If set and the connection is
gone because of sysfs abort, reading from the device will return
-ECONNABORTED.
Signed-off-by: NSzymon Lukasz <noh4hss@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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: NMiklos Szeredi <mszeredi@redhat.com>

If the IOCB_DSYNC flag is set a sync is not being performed by
fuse_file_write_iter.

Honor IOCB_DSYNC/IOCB_SYNC by setting O_DYSNC/O_SYNC respectively in the
flags filed of the write request.

We don't need to sync data or metadata, since fuse_perform_write() does
write-through and the filesystem is responsible for updating file times.

Original patch by Vitaly Zolotusky.
Reported-by: NNate Clark <nate@neworld.us>
Cc: Vitaly Zolotusky <vitaly@unitc.com>.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Commit 8fba54ae ("fuse: direct-io: don't dirty ITER_BVEC pages") fixes
the ITER_BVEC page deadlock for direct io in fuse by checking in
fuse_direct_io(), whether the page is a bvec page or not, before locking
it.  However, this check is missed when the "async_dio" mount option is
enabled.  In this case, set_page_dirty_lock() is called from the req->end
callback in request_end(), when the fuse thread is returning from userspace
to respond to the read request.  This will cause the same deadlock because
the bvec condition is not checked in this path.

Here is the stack of the deadlocked thread, while returning from userspace:

[13706.656686] INFO: task glusterfs:3006 blocked for more than 120 seconds.
[13706.657808] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
this message.
[13706.658788] glusterfs       D ffffffff816c80f0     0  3006      1
0x00000080
[13706.658797]  ffff8800d6713a58 0000000000000086 ffff8800d9ad7000
ffff8800d9ad5400
[13706.658799]  ffff88011ffd5cc0 ffff8800d6710008 ffff88011fd176c0
7fffffffffffffff
[13706.658801]  0000000000000002 ffffffff816c80f0 ffff8800d6713a78
ffffffff816c790e
[13706.658803] Call Trace:
[13706.658809]  [<ffffffff816c80f0>] ? bit_wait_io_timeout+0x80/0x80
[13706.658811]  [<ffffffff816c790e>] schedule+0x3e/0x90
[13706.658813]  [<ffffffff816ca7e5>] schedule_timeout+0x1b5/0x210
[13706.658816]  [<ffffffff81073ffb>] ? gup_pud_range+0x1db/0x1f0
[13706.658817]  [<ffffffff810668fe>] ? kvm_clock_read+0x1e/0x20
[13706.658819]  [<ffffffff81066909>] ? kvm_clock_get_cycles+0x9/0x10
[13706.658822]  [<ffffffff810f5792>] ? ktime_get+0x52/0xc0
[13706.658824]  [<ffffffff816c6f04>] io_schedule_timeout+0xa4/0x110
[13706.658826]  [<ffffffff816c8126>] bit_wait_io+0x36/0x50
[13706.658828]  [<ffffffff816c7d06>] __wait_on_bit_lock+0x76/0xb0
[13706.658831]  [<ffffffffa0545636>] ? lock_request+0x46/0x70 [fuse]
[13706.658834]  [<ffffffff8118800a>] __lock_page+0xaa/0xb0
[13706.658836]  [<ffffffff810c8500>] ? wake_atomic_t_function+0x40/0x40
[13706.658838]  [<ffffffff81194d08>] set_page_dirty_lock+0x58/0x60
[13706.658841]  [<ffffffffa054d968>] fuse_release_user_pages+0x58/0x70 [fuse]
[13706.658844]  [<ffffffffa0551430>] ? fuse_aio_complete+0x190/0x190 [fuse]
[13706.658847]  [<ffffffffa0551459>] fuse_aio_complete_req+0x29/0x90 [fuse]
[13706.658849]  [<ffffffffa05471e9>] request_end+0xd9/0x190 [fuse]
[13706.658852]  [<ffffffffa0549126>] fuse_dev_do_write+0x336/0x490 [fuse]
[13706.658854]  [<ffffffffa054963e>] fuse_dev_write+0x6e/0xa0 [fuse]
[13706.658857]  [<ffffffff812a9ef3>] ? security_file_permission+0x23/0x90
[13706.658859]  [<ffffffff81205300>] do_iter_readv_writev+0x60/0x90
[13706.658862]  [<ffffffffa05495d0>] ? fuse_dev_splice_write+0x350/0x350
[fuse]
[13706.658863]  [<ffffffff812062a1>] do_readv_writev+0x171/0x1f0
[13706.658866]  [<ffffffff810b3d00>] ? try_to_wake_up+0x210/0x210
[13706.658868]  [<ffffffff81206361>] vfs_writev+0x41/0x50
[13706.658870]  [<ffffffff81206496>] SyS_writev+0x56/0xf0
[13706.658872]  [<ffffffff810257a1>] ? syscall_trace_leave+0xf1/0x160
[13706.658874]  [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71

Fix this by making should_dirty a fuse_io_priv parameter that can be
checked in fuse_aio_complete_req().
Reported-by: NTiger Yang <tiger.yang@oracle.com>
Signed-off-by: NAshish Samant <ashish.samant@oracle.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

It is not needed anymore since bdi is initialized whenever superblock
exists.

CC: Miklos Szeredi <miklos@szeredi.hu>
CC: linux-fsdevel@vger.kernel.org
Suggested-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Miklos Szeredi <miklos@szeredi.hu>
CC: linux-fsdevel@vger.kernel.org
Acked-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

When the userspace process servicing fuse requests is running in
a pid namespace then pids passed via the fuse fd are not being
translated into that process' namespace. Translation is necessary
for the pid to be useful to that process.

Since no use case currently exists for changing namespaces all
translations can be done relative to the pid namespace in use
when fuse_conn_init() is called. For fuse this translates to
mount time, and for cuse this is when /dev/cuse is opened. IO for
this connection from another namespace will return errors.

Requests from processes whose pid cannot be translated into the
target namespace will have a value of 0 for in.h.pid.

File locking changes based on previous work done by Eric
Biederman.
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

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: NMiklos Szeredi <mszeredi@redhat.com>

Since we need to change the implementation, stop exposing internals.

Provide KREF_INIT() to allow static initialization of struct kref.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Add missing dentry initialization to root dentry.

Fixes: f75fdf22 ("fuse: don't use ->d_time")
Reported-by: NAndreas Reis <andreas.reis@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

In preparation for posix acl support, rework fuse to use xattr handlers and
the generic setxattr/getxattr/listxattr callbacks.  Split the xattr code
out into it's own file, and promote symbols to module-global scope as
needed.

Functionally these changes have no impact, as fuse still uses a single
handler for all xattrs which uses the old callbacks.
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Only two flags: "default_permissions" and "allow_other".  All other flags
are handled via bitfields.  So convert these two as well.  They don't
change during the lifetime of the filesystem, so this is quite safe.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Add a new INIT flag, FUSE_POSIX_ACL, for negotiating ACL support with
userspace.  When it is set in the INIT response, ACL support will be
enabled.  ACL support also implies "default_permissions".

When ACL support is enabled, the kernel will cache and have responsibility
for enforcing ACLs.  ACL xattrs will be passed to userspace, which is
responsible for updating the ACLs in the filesystem, keeping the file mode
in sync, and inheritance of default ACLs when new filesystem nodes are
created.
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Only userspace filesystem can do the killing of suid/sgid without races.
So introduce an INIT flag and negotiate support for this.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

To avoid clearing of capabilities or security related extended
attributes too early, inode_change_ok() will need to take dentry instead
of inode. Propagate it down to fuse_do_setattr().
Acked-by: NMiklos Szeredi <mszeredi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

While sending the blocking directIO in fuse, the write request is broken
into sub-requests, each of default size 128k and all the requests are sent
in non-blocking background mode if async_dio mode is supported by libfuse.
The process which issue the write wait for the completion of all the
sub-requests. Sending multiple requests parallely gives a chance to perform
parallel writes in the user space fuse implementation if it is
multi-threaded and hence improves the performance.

When there is a size extending aio dio write, we switch to blocking mode so
that we can properly update the size of the file after completion of the
writes. However, in this situation all the sub-requests are sent in
serialized manner where the next request is sent only after receiving the
reply of the current request. Hence the multi-threaded user space
implementation is not utilized properly.

This patch changes the size extending aio dio behavior to exactly follow
blocking dio. For multi threaded fuse implementation having 10 threads and
using buffer size of 64MB to perform async directIO, we are getting double
the speed.
Signed-off-by: NAshish Sangwan <ashishsangwan2@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Negotiate with userspace filesystems whether they support parallel readdir
and lookup.  Disable parallelism by default for fear of breaking fuse
filesystems.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Fixes: 9902af79 ("parallel lookups: actual switch to rwsem")
Fixes: d9b3dbdc ("fuse: switch to ->iterate_shared()")

The 'reqs' member of fuse_io_priv serves two purposes. First is to track
the number of oustanding async requests to the server and to signal that
the io request is completed. The second is to be a reference count on the
structure to know when it can be freed.

For sync io requests these purposes can be at odds.  fuse_direct_IO() wants
to block until the request is done, and since the signal is sent when
'reqs' reaches 0 it cannot keep a reference to the object. Yet it needs to
use the object after the userspace server has completed processing
requests. This leads to some handshaking and special casing that it
needlessly complicated and responsible for at least one race condition.

It's much cleaner and safer to maintain a separate reference count for the
object lifecycle and to let 'reqs' just be a count of outstanding requests
to the userspace server. Then we can know for sure when it is safe to free
the object without any handshaking or special cases.

The catch here is that most of the time these objects are stack allocated
and should not be freed. Initializing these objects with a single reference
that is never released prevents accidental attempts to free the objects.

Fixes: 9d5722b7 ("fuse: handle synchronous iocbs internally")
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

A useful performance improvement for accessing virtual machine images
via FUSE mount.

See https://bugzilla.redhat.com/show_bug.cgi?id=1220173 for a use-case
for glusterFS.
Signed-off-by: NRavishankar N <ravishankar@redhat.com>
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>

Make each fuse device clone refer to a separate processing queue.  The only
constraint on userspace code is that the request answer must be written to
the same device clone as it was read off.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Allow fuse device clones to refer to be distinguished.  This patch just
adds the infrastructure by associating a separate "struct fuse_dev" with
each clone.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

When an unlocked request is aborted, it is moved from fpq->io to a private
list.  Then, after unlocking fpq->lock, the private list is processed and
the requests are finished off.

To protect the private list, we need to mark the request with a flag, so if
in the meantime the request is unlocked the list is not corrupted.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Add a fpq->lock for protecting members of struct fuse_pqueue and FR_LOCKED
request flag.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

This will allow checking ->connected just with the processing queue lock.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

This is just two fields: fc->io and fc->processing.

This patch just rearranges the fields, no functional change.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

This will allow checking ->connected just with the input queue lock.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

The input queue contains normal requests (fc->pending), forgets
(fc->forget_*) and interrupts (fc->interrupts).  There's also fc->waitq and
fc->fasync for waking up the readers of the fuse device when a request is
available.

The fc->reqctr is also moved to the input queue (assigned to the request
when the request is added to the input queue.

This patch just rearranges the fields, no functional change.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Use flags for representing the state in fuse_req.  This is needed since
req->list will be protected by different locks in different states, hence
we'll want the state itself to be split into distinct bits, each protected
with the relevant lock in that state.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

FUSE_REQ_INIT is actually the same state as FUSE_REQ_PENDING and
FUSE_REQ_READING and FUSE_REQ_WRITING can be merged into a common
FUSE_REQ_IO state.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Reuse req->waitq.lock for protecting FR_ABORTED and FR_LOCKED flags.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Finer grained locking will mean there's no single lock to protect
modification of bitfileds in fuse_req.

So move to using bitops.  Can use the non-atomic variants for those which
happen while the request definitely has only one reference.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Based on a patch from Maxim Patlasov <MPatlasov@parallels.com>.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Theoretically we need to order setting of various fields in fc with
fc->initialized.

No known bug reports related to this yet.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>