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>

Allow an open fuse device to be "cloned".  Userspace can create a clone by:

      newfd = open("/dev/fuse", O_RDWR)
      ioctl(newfd, FUSE_DEV_IOC_CLONE, &oldfd);

At this point newfd will refer to the same fuse connection as oldfd.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: NAshish Samant <ashish.samant@oracle.com>

Here some additional changes to set a capability flag so that clients can
detect when it's appropriate to return -ENOSYS from open.

This amends the following commit introduced in 3.14:

  7678ac50  fuse: support clients that don't implement 'open'

However we can only add the flag to 3.15 and later since there was no
protocol version update in 3.14.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: <stable@vger.kernel.org> # v3.15+

Support RENAME_EXCHANGE and RENAME_NOREPLACE flags on the userspace ABI.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The patch extends fuse_setattr_in, and extends the flush procedure
(fuse_flush_times()) called on ->write_inode() to send the ctime as well as
mtime.
Signed-off-by: NMaxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Allow userspace fs to specify time granularity.

This is needed because with writeback_cache mode the kernel is responsible
for generating mtime and ctime, but if the underlying filesystem doesn't
support nanosecond granularity then the cache will contain a different
value from the one stored on the filesystem resulting in a change of times
after a cache flush.

Make the default granularity 1s.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Introduce a bit kernel and userspace exchange between each-other on
the init stage and turn writeback on if the userspace want this and
mount option 'allow_wbcache' is present (controlled by fusermount).

Also add each writable file into per-inode write list and call the
generic_file_aio_write to make use of the Linux page cache engine.
Signed-off-by: NMaxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Without async DIO write requests to a single file were always serialized.
With async DIO that's no longer the case.

So don't turn on async DIO by default for fear of breaking backward
compatibility.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Commit 7e98d530 (Synchronize fuse header with
one used in library) added #ifdef __linux__ around defines if it is not set.
The kernel build is self-contained and can be built on non-Linux toolchains.
After the mentioned commit builds on non-Linux toolchains will try to include
stdint.h and fail due to -nostdinc, and then fail with a bunch of undefined type
errors.

Fix by checking for __KERNEL__ instead of __linux__ and using the standard int
types instead of the linux specific ones.
Reported-by: NArve Hjønnevåg <arve@android.com>
Reported-by: NColin Cross <ccross@android.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

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>

The library one has provisions for use in *BSD, add them to the kernel one too.
They don't hurt and ease maintenance.
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>

Yeah, we have a capability flag for this as well, so this is not strictly
necessary, but it doesn't hurt either.
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>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add missing flags that userspace derived from the protocol version number.  This
makes the protocol more flexible.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

FUSE_AUTO_INVAL_DATA is provided to enable updated/auto cache
invalidation logic.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

fallocate filesystem operation preallocates media space for the given file.
If fallocate returns success then any subsequent write to the given range
never fails with 'not enough space' error.
Signed-off-by: NAnatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Use the ISO C standard compliant form instead of the gcc extension in the
interface definition.
Reported-by: NShachar Sharon <ssnail@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Allows a FUSE file-system to tell the kernel when a file or directory is
deleted. If the specified dentry has the specified inode number, the kernel will
unhash it.

The current 'fuse_notify_inval_entry' does not cause the kernel to clean up
directories that are in use properly, and as a result the users of those
directories see incorrect semantics from the file-system. The error condition
seen when 'fuse_notify_inval_entry' is used to notify of a deleted directory is
avoided when 'fuse_notify_delete' is used instead.

The following scenario demonstrates the difference:
1. User A chdirs into 'testdir' and starts reading 'testfile'.
2. User B rm -rf 'testdir'.
3. User B creates 'testdir'.
4. User C chdirs into 'testdir'.

If you run the above within the same machine on any file-system (including fuse
file-systems), there is no problem: user C is able to chdir into the new
testdir. The old testdir is removed from the dentry tree, but still open by user
A.

If operations 2 and 3 are performed via the network such that the fuse
file-system uses one of the notify functions to tell the kernel that the nodes
are gone, then the following error occurs for user C while user A holds the
original directory open:

muirj@empacher:~> ls /test/testdir
ls: cannot access /test/testdir: No such file or directory

The issue here is that the kernel still has a dentry for testdir, and so it is
requesting the attributes for the old directory, while the file-system is
responding that the directory no longer exists.

If on the other hand, if the file-system can notify the kernel that the
directory is deleted using the new 'fuse_notify_delete' function, then the above
ls will find the new directory as expected.
Signed-off-by: NJohn Muir <john@jmuir.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Multiplexing filesystems may want to support ioctls on the underlying
files and directores (e.g. FS_IOC_{GET,SET}FLAGS).

Ioctl support on directories was missing so add it now.
Reported-by: NAntonio SJ Musumeci <bile@landofbile.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Commit a9ff4f87 "fuse: support BSD locking semantics" overlooked a
number of issues with supporing flock locks over existing POSIX
locking infrastructure:

  - it's not backward compatible, passing flock(2) calls to userspace
    unconditionally (if userspace sets FUSE_POSIX_LOCKS)

  - it doesn't cater for the fact that flock locks are automatically
    unlocked on file release

  - it doesn't take into account the fact that flock exclusive locks
    (write locks) don't need an fd opened for write.

The last one invalidates the original premise of the patch that flock
locks can be emulated with POSIX locks.

This patch fixes the first two issues.  The last one needs to be fixed
in userspace if the filesystem assumed that a write lock will happen
only on a file operned for write (as in the case of the current fuse
library).
Reported-by: NSebastian Pipping <webmaster@hartwork.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

In kernel ABI version 7.16 and later FUSE_IOCTL_RETRY reply from a
unrestricted IOCTL request shall return with an array of 'struct
fuse_ioctl_iovec' instead of 'struct iovec'.  This fixes the ABI
ambiguity of 32bit vs. 64bit.
Reported-by: N"ccmail111" <ccmail111@yahoo.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
CC: Tejun Heo <tj@kernel.org>

Terje Malmedal reports that a fuse filesystem with 32 million inodes
on a machine with lots of memory can take up to 30 minutes to process
FORGET requests when all those inodes are evicted from the icache.

To solve this, create a BATCH_FORGET request that allows up to about
8000 FORGET requests to be sent in a single message.

This request is only sent if userspace supports interface version 7.16
or later, otherwise fall back to sending individual FORGET messages.
Reported-by: NTerje Malmedal <terje.malmedal@usit.uio.no>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Userspace filesystem can request data to be retrieved from the inode's
mapping.  This request is synchronous and the retrieved data is queued
as a new request.  If the write to the fuse device returns an error
then the retrieve request was not completed and a reply will not be
sent.

Only present pages are returned in the retrieve reply.  Retrieving
stops when it finds a non-present page and only data prior to that is
returned.

This request doesn't change the dirty state of pages.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Userspace filesystem can request data to be stored in the inode's
mapping.  This request is synchronous and has no reply.  If the write
to the fuse device returns an error then the store request was not
fully completed (but may have updated some pages).

If the stored data overflows the current file size, then the size is
extended, similarly to a write(2) on the filesystem.

Pages which have been completely stored are marked uptodate.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Allow userspace filesystem implementation to use splice() to write to
the fuse device.  The semantics of using splice() are:

 1) buffer the message header and data in a temporary pipe
 2) with a *single* splice() call move the message from the temporary pipe
    to the fuse device

The READ reply message has the most interesting use for this, since
now the data from an arbitrary file descriptor (which could be a
regular file, a block device or a socket) can be tranferred into the
fuse device without having to go through a userspace buffer.  It will
also allow zero copy moving of pages.

One caveat is that the protocol on the fuse device requires the length
of the whole message to be written into the header.  But the length of
the data transferred into the temporary pipe may not be known in
advance.  The current library implementation works around this by
using vmplice to write the header and modifying the header after
splicing the data into the pipe (error handling omitted):

	struct fuse_out_header out;

	iov.iov_base = &out;
	iov.iov_len = sizeof(struct fuse_out_header);
	vmsplice(pip[1], &iov, 1, 0);
	len = splice(input_fd, input_offset, pip[1], NULL, len, 0);
	/* retrospectively modify the header: */
	out.len = len + sizeof(struct fuse_out_header);
	splice(pip[0], NULL, fuse_chan_fd(req->ch), NULL, out.len, flags);

This works since vmsplice only saves a pointer to the data, it does
not copy the data itself.

Since pipes are currently limited to 16 pages and messages need to be
spliced atomically, the length of the data is limited to 15 pages (or
60kB for 4k pages).
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Clarify how the protocol version should be negotiated between kernel
and userspace.  Notably libfuse didn't correctly handle the case when
the supported major versions didn't match.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The practical values for these limits depend on the design of the
filesystem server so let userspace set them at initialization time.
Signed-off-by: NCsaba Henk <csaba@gluster.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add notification messages that allow the filesystem to invalidate VFS
caches.

Two notifications are added:

 1) inode invalidation

   - invalidate cached attributes
   - invalidate a range of pages in the page cache (this is optional)

 2) dentry invalidation

   - try to invalidate a subtree in the dentry cache

Care must be taken while accessing the 'struct super_block' for the
mount, as it can go away while an invalidation is in progress.  To
prevent this, introduce a rw-semaphore, that is taken for read during
the invalidation and taken for write in the ->kill_sb callback.

Cc: Csaba Henk <csaba@gluster.com>
Cc: Anand Avati <avati@zresearch.com>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

This patch lets filesystems handle masking the file mode on creation.
This is needed if filesystem is using ACLs.

 - The CREATE, MKDIR and MKNOD requests are extended with a "umask"
   parameter.

 - A new FUSE_DONT_MASK flag is added to the INIT request/reply.  With
   this the filesystem may request that the create mode is not masked.

CC: Jean-Pierre André <jean-pierre.andre@wanadoo.fr>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

CUSE enables implementing character devices in userspace.  With recent
additions of ioctl and poll support, FUSE already has most of what's
necessary to implement character devices.  All CUSE has to do is
bonding all those components - FUSE, chardev and the driver model -
nicely.

When client opens /dev/cuse, kernel starts conversation with
CUSE_INIT.  The client tells CUSE which device it wants to create.  As
the previous patch made fuse_file usable without associated
fuse_inode, CUSE doesn't create super block or inodes.  It attaches
fuse_file to cdev file->private_data during open and set ff->fi to
NULL.  The rest of the operation is almost identical to FUSE direct IO
case.

Each CUSE device has a corresponding directory /sys/class/cuse/DEVNAME
(which is symlink to /sys/devices/virtual/class/DEVNAME if
SYSFS_DEPRECATED is turned off) which hosts "waiting" and "abort"
among other things.  Those two files have the same meaning as the FUSE
control files.

The only notable lacking feature compared to in-kernel implementation
is mmap support.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Change interface version to 7.11 after adding the IOCTL and POLL
messages.

Also clean up the <linux/fuse.h> header a bit:
  - update copyright date to 2008
  - fix checkpatch warning:
      WARNING: Use #include <linux/types.h> instead of <asm/types.h>
  - remove FUSE_MAJOR define, which is not being used any more
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Implement poll support.  Polled files are indexed using kh in a RB
tree rooted at fuse_conn->polled_files.

Client should send FUSE_NOTIFY_POLL notification once after processing
FUSE_POLL which has FUSE_POLL_SCHEDULE_NOTIFY set.  Sending
notification unconditionally after the latest poll or everytime file
content might have changed is inefficient but won't cause malfunction.

fuse_file_poll() can sleep and requires patches from the following
thread which allows f_op->poll() to sleep.

  http://thread.gmane.org/gmane.linux.kernel/726176Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Clients always used to write only in response to read requests.  To
implement poll efficiently, clients should be able to issue
unsolicited notifications.  This patch implements basic notification
support.

Zero fuse_out_header.unique is now accepted and considered unsolicited
notification and the error field contains notification code.  This
patch doesn't implement any actual notification.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Generic ioctl support is tricky to implement because only the ioctl
implementation itself knows which memory regions need to be read
and/or written.  To support this, fuse client can request retry of
ioctl specifying memory regions to read and write.  Deep copying
(nested pointers) can be implemented by retrying multiple times
resolving one depth of dereference at a time.

For security and cleanliness considerations, ioctl implementation has
restricted mode where the kernel determines data transfer directions
and sizes using the _IOC_*() macros on the ioctl command.  In this
mode, retry is not allowed.

For all FUSE servers, restricted mode is enforced.  Unrestricted ioctl
will be used by CUSE.

Plese read the comment on top of fs/fuse/file.c::fuse_file_do_ioctl()
for more information.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Move FUSE_MINOR to miscdevice.h.  While at it, de-uglify the file.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Let the client request nonseekable open using FOPEN_NONSEEKABLE and
call nonseekable_open() on the file if requested.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

Add include protectors to include/linux/fuse.h and fs/fuse/fuse_i.h.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>