Existing flag fc->blocked is used to suspend request allocation both in case
of many background request submitted and period of time before init_reply
arrives from userspace. Next patch will skip blocking allocations of
synchronous request (disregarding fc->blocked). This is mostly OK, but
we still need to suspend allocations if init_reply is not arrived yet. The
patch introduces flag fc->initialized which will serve this purpose.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

There are two types of processing requests in FUSE: synchronous (via
fuse_request_send()) and asynchronous (via adding to fc->bg_queue).

Fortunately, the type of processing is always known in advance, at the time
of request allocation. This preparatory patch utilizes this fact making
fuse_get_req() aware about the type. Next patches will use it.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

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

This patch is a follow up on below patch:

[PATCH] exportfs: add FILEID_INVALID to indicate invalid fid_type
commit: 216b6cbdSigned-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NVivek Trivedi <t.vivek@samsung.com>
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>
Acked-by: NSage Weil <sage@inktank.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

For some filesystems (e.g. GlusterFS), the cost of performing a
normal readdir and readdirplus are identical.  Since adaptively
using readdirplus has no benefit for those systems, give
users/filesystems the option to control adaptive readdirplus use.

v2 of this patch incorporates Miklos's suggestion to simplify the code,
as well as improving consistency of macro names and documentation.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

commit 626cf236 "poll: add poll_requested_events()..." enabled us to send the
requested events to the filesystem.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

drop_nlink() warns if nlink is already zero.  This is triggerable by a buggy
userspace filesystem.  The cure, I think, is worse than the disease so disable
the warning.
Reported-by: NTero Roponen <tero.roponen@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The all pointers within fuse_req must point to valid memory once
fuse_force_forget() returns.

This bug appeared in "fuse: implement NFS-like readdirplus support"
and was never in any official Linux release.

I tested the fuse_force_forget() code path by injecting to fake -ENOMEM and
verified the FORGET operation was called properly in userspace.
Signed-off-by: NEric Wong <normalperson@yhbt.net>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Use the same adaptive readdirplus mechanism as NFS:

http://permalink.gmane.org/gmane.linux.nfs/49299

If the user space implementation wants to disable readdirplus
temporarily, it could just return ENOTSUPP. Then kernel will
recall it with readdir.
Signed-off-by: NFeng Shuo <steve.shuo.feng@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Commit c69e8d9c added rcu lock to fuse/dir.c It was assuming
that 'task' is some other process but in fact this parameter always
equals to 'current'. Inline this parameter to make it more readable
and remove RCU lock as it is not needed when access current process
credentials.
Signed-off-by: NAnatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Fix the following sparse warnings:

fs/fuse/file.c:1216:43: warning: cast removes address space of expression
fs/fuse/file.c:1216:43: warning: incorrect type in initializer (different address spaces)
fs/fuse/file.c:1216:43:    expected void [noderef] <asn:1>*iov_base
fs/fuse/file.c:1216:43:    got void *<noident>
fs/fuse/file.c:1241:43: warning: cast removes address space of expression
fs/fuse/file.c:1241:43: warning: incorrect type in initializer (different address spaces)
fs/fuse/file.c:1241:43:    expected void [noderef] <asn:1>*iov_base
fs/fuse/file.c:1241:43:    got void *<noident>
fs/fuse/file.c:1267:43: warning: cast removes address space of expression
fs/fuse/file.c:1267:43: warning: incorrect type in initializer (different address spaces)
fs/fuse/file.c:1267:43:    expected void [noderef] <asn:1>*iov_base
fs/fuse/file.c:1267:43:    got void *<noident>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

__fuse_direct_io() allocates fuse-requests by calling fuse_get_req(fc, n). The
patch calculates 'n' based on iov[] array. This is useful because allocating
FUSE_MAX_PAGES_PER_REQ page pointers and descriptors for each fuse request
would be waste of memory in case of iov-s of smaller size.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Let fuse_get_user_pages() pack as many iov-s to a single fuse_req as
possible. This is very beneficial in case of iov[] consisting of many
iov-s of relatively small sizes (e.g. PAGE_SIZE).
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch makes preliminary work for the next patch optimizing scatter-gather
direct IO. The idea is to allow fuse_get_user_pages() to pack as many iov-s
to each fuse request as possible. So, here we only rework all related
call-paths to carry iov[] from fuse_direct_IO() to fuse_get_user_pages().
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Previously, anyone who set flag 'argpages' only filled req->pages[] and set
per-request page_offset. This patch re-works all cases where argpages=1 to
fill req->page_descs[] properly.

Having req->page_descs[] filled properly allows to re-work fuse_copy_pages()
to copy page fragments described by req->page_descs[]. This will be useful
for next patches optimizing direct_IO.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The ability to save page pointers along with lengths and offsets in fuse_req
will be useful to cover several iovec-s with a single fuse_req.

Per-request page_offset is removed because anybody who need it can use
req->page_descs[0].offset instead.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

fuse_do_ioctl() already calculates the number of pages it's going to use. It is
stored in 'num_pages' variable. So the patch simply uses it for allocating
fuse_req.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch allocates as many page pointers in fuse_req as needed to cover
interval [pos .. pos+len-1]. Inline helper fuse_wr_pages() is introduced
to hide this cumbersome arithmetic.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch uses 'nr_pages' argument of fuse_readpages() as heuristics for the
number of page pointers to allocate.

This can be improved further by taking in consideration fc->max_read and gaps
between page indices, but it's not clear whether it's worthy or not.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch reworks fuse_retrieve() to allocate only so many page pointers
as needed. The core part of the patch is the following calculation:

	num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;

(thanks Miklos for formula). All other changes are mostly shuffling lines.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch categorizes all fuse_get_req() invocations into two categories:
 - fuse_get_req_nopages(fc) - when caller doesn't care about req->pages
 - fuse_get_req(fc, n) - when caller need n page pointers (n > 0)

Adding fuse_get_req_nopages() helps to avoid numerous fuse_get_req(fc, 0)
scattered over code. Now it's clear from the first glance when a caller need
fuse_req with page pointers.

The patch doesn't make any logic changes. In multi-page case, it silly
allocates array of FUSE_MAX_PAGES_PER_REQ page pointers. This will be amended
by future patches.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch removes inline array of FUSE_MAX_PAGES_PER_REQ page pointers from
fuse_req. Instead of that, req->pages may now point either to small inline
array or to an array allocated dynamically.

This essentially means that all callers of fuse_request_alloc[_nofs] should
pass the number of pages needed explicitly.

The patch doesn't make any logic changes.
Signed-off-by: NMaxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

This patch implements readdirplus support in FUSE, similar to NFS.
The payload returned in the readdirplus call contains
'fuse_entry_out' structure thereby providing all the necessary inputs
for 'faking' a lookup() operation on the spot.

If the dentry and inode already existed (for e.g. in a re-run of ls -l)
then just the inode attributes timeout and dentry timeout are refreshed.

With a simple client->network->server implementation of a FUSE based
filesystem, the following performance observations were made:

Test: Performing a filesystem crawl over 20,000 files with

sh# time ls -lR /mnt

Without readdirplus:
Run 1: 18.1s
Run 2: 16.0s
Run 3: 16.2s

With readdirplus:
Run 1: 4.1s
Run 2: 3.8s
Run 3: 3.8s

The performance improvement is significant as it avoided 20,000 upcalls
calls (lookup). Cache consistency is no worse than what already is.
Signed-off-by: NAnand V. Avati <avati@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The variables mapping,index are initialized but never used
otherwise, so remove the unused variables.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Fix the following sparse warning:

fs/fuse/file.c:2249:6: warning: symbol 'fuse_file_fallocate' was not declared. Should it be static?
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Given that CUSE depends on FUSE, it only makes sense to move its
Kconfig entry into the FUSE Kconfig file.  Also, add a few grammatical
and semantic touchups.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Fix the following compiler warnings:

fs/fuse/cuse.c: In function 'cuse_process_init_reply':
fs/fuse/cuse.c:288:24: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
fs/fuse/cuse.c:272:14: note: 'val' was declared here
fs/fuse/cuse.c:284:10: warning: 'key' may be used uninitialized in this function [-Wmaybe-uninitialized]
fs/fuse/cuse.c:272:8: note: 'key' was declared here
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Sysfs doesn't allow two devices with the same name, but we register a
sysfs entry for each cuse device without checking for name collisions.
This extends the registration to first check whether the name was already
registered.

To avoid race-conditions between the name-check and linking the device, we
need to protect the whole registration with a mutex.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

We need to check for name-collisions during cuse-device registration. To
avoid race-conditions, this needs to be protected during the whole device
registration. Therefore, replace the spinlocks by mutexes first so we can
safely extend the locked regions to include more expensive or sleeping
code paths.
Signed-off-by: NDavid Herrmann <dh.herrmann@googlemail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

But the kernel decided to call it "origin" instead.  Fix most of the
sites.
Acked-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use kuid_t and kgid_t in struct fuse_conn and struct fuse_mount_data.

The connection between between a fuse filesystem and a fuse daemon is
established when a fuse filesystem is mounted and provided with a file
descriptor the fuse daemon created by opening /dev/fuse.

For now restrict the communication of uids and gids between the fuse
filesystem and the fuse daemon to the initial user namespace.  Enforce
this by verifying the file descriptor passed to the mount of fuse was
opened in the initial user namespace.  Ensuring the mount happens in
the initial user namespace is not necessary as mounts from non-initial
user namespaces are not yet allowed.

In fuse_req_init_context convert the currrent fsuid and fsgid into the
initial user namespace for the request that will be sent to the fuse
daemon.

In fuse_fill_attr convert the uid and gid passed from the fuse daemon
from the initial user namespace into kuids and kgids.

In iattr_to_fattr called from fuse_setattr convert kuids and kgids
into the uids and gids in the initial user namespace before passing
them to the fuse filesystem.

In fuse_change_attributes_common called from fuse_dentry_revalidate,
fuse_permission, fuse_geattr, and fuse_setattr, and fuse_iget convert
the uid and gid from the fuse daemon into a kuid and a kgid to store
on the fuse inode.

By default fuse mounts are restricted to task whose uid, suid, and
euid matches the fuse user_id and whose gid, sgid, and egid matches
the fuse group id.  Convert the user_id and group_id mount options
into kuids and kgids at mount time, and use uid_eq and gid_eq to
compare the in fuse_allow_task.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Move actual pte filling for non-linear file mappings into the new special
vma operation: ->remap_pages().

Filesystems must implement this method to get non-linear mapping support,
if it uses filemap_fault() then generic_file_remap_pages() can be used.

Now device drivers can implement this method and obtain nonlinear vma support.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>	#arch/tile
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's no reason to call rcu_barrier() on every
deactivate_locked_super().  We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.

Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths.  E.g.  on my machine exit_group() of a last process in IPC
namespace takes 0.07538s.  rcu_barrier() takes 0.05188s of that time.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

simplifies a bunch of callers...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In some cases fuse_retrieve() would return a short byte count if offset was
non-zero.  The data returned was correct, though.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org

gcc 4.6.3 complains about uninitialized variables in fs/fuse/control.c:

  CC      fs/fuse/control.o
fs/fuse/control.c: In function 'fuse_conn_congestion_threshold_write':
fs/fuse/control.c:165:29: warning: 'val' may be used uninitialized in this function [-Wuninitialized]
fs/fuse/control.c: In function 'fuse_conn_max_background_write':
fs/fuse/control.c:128:23: warning: 'val' may be used uninitialized in this function [-Wuninitialized]

fuse_conn_limit_write() will always return non-zero unless the &val
is modified, so the warning is misleading. Let the compiler know
about it by marking 'val' with 'uninitialized_var'.
Signed-off-by: NDaniel Mack <zonque@gmail.com>
Cc: Brian Foster <bfoster@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Luca Risolia reported that a CUSE daemon will continue to run even if
initialization of the emulated device failes for some reason (e.g. the device
number is already registered by another driver).

This patch disconnects the fuse device on error, which will make the userspace
CUSE daemon exit, albeit without indication about what the problem was.
Reported-by: NLuca Risolia <luca.risolia@studio.unibo.it>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

fuse_conn_kill() removed fc->entry, called fuse_ctl_remove_conn() and
fuse_bdi_destroy().  None of which is appropriate for cuse cleanup.

The fuse_ctl_remove_conn() decrements the nlink on the control filesystem, which
is totally bogus.  The others are harmless but unnecessary.

So move these out from fuse_conn_kill() to fuse_put_super() where they belong.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>