linux-stable.git/fs/fuse, branch v5.1.7

fuse: Add FOPEN_STREAM to use stream_open()

2019-05-25T16:16:47+00:00

commit bbd84f33652f852ce5992d65db4d020aba21f882 upstream.

Starting from commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per
POSIX") files opened even via nonseekable_open gate read and write via lock
and do not allow them to be run simultaneously. This can create read vs
write deadlock if a filesystem is trying to implement a socket-like file
which is intended to be simultaneously used for both read and write from
filesystem client.  See commit 10dce8af3422 ("fs: stream_open - opener for
stream-like files so that read and write can run simultaneously without
deadlock") for details and e.g. commit 581d21a2d02a ("xenbus: fix deadlock
on writes to /proc/xen/xenbus") for a similar deadlock example on
/proc/xen/xenbus.

To avoid such deadlock it was tempting to adjust fuse_finish_open to use
stream_open instead of nonseekable_open on just FOPEN_NONSEEKABLE flags,
but grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
and in particular GVFS which actually uses offset in its read and write
handlers

	https://codesearch.debian.net/search?q=-%3Enonseekable+%3D
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481

so if we would do such a change it will break a real user.

Add another flag (FOPEN_STREAM) for filesystem servers to indicate that the
opened handler is having stream-like semantics; does not use file position
and thus the kernel is free to issue simultaneous read and write request on
opened file handle.

This patch together with stream_open() should be added to stable kernels
starting from v3.14+. This will allow to patch OSSPD and other FUSE
filesystems that provide stream-like files to return FOPEN_STREAM |
FOPEN_NONSEEKABLE in open handler and this way avoid the deadlock on all
kernel versions. This should work because fuse_finish_open ignores unknown
open flags returned from a filesystem and so passing FOPEN_STREAM to a
kernel that is not aware of this flag cannot hurt. In turn the kernel that
is not aware of FOPEN_STREAM will be < v3.14 where just FOPEN_NONSEEKABLE
is sufficient to implement streams without read vs write deadlock.

Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Kirill Smelkov 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: honor RLIMIT_FSIZE in fuse_file_fallocate

2019-05-25T16:16:34+00:00

commit 0cbade024ba501313da3b7e5dd2a188a6bc491b5 upstream.

fstests generic/228 reported this failure that fuse fallocate does not
honor what 'ulimit -f' has set.

This adds the necessary inode_newsize_ok() check.

Signed-off-by: Liu Bo 
Fixes: 05ba1f082300 ("fuse: add FALLOCATE operation")
Cc:  # v3.5
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix writepages on 32bit

2019-05-25T16:16:34+00:00

commit 9de5be06d0a89ca97b5ab902694d42dfd2bb77d2 upstream.

Writepage requests were cropped to i_size & 0xffffffff, which meant that
mmaped writes to any file larger than 4G might be silently discarded.

Fix by storing the file size in a properly sized variable (loff_t instead
of size_t).

Reported-by: Antonio SJ Musumeci 
Fixes: 6eaf4782eb09 ("fuse: writepages: crop secondary requests")
Cc:  # v3.13
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'page-refs' (page ref overflow)

2019-04-14T22:09:40+00:00

Merge page ref overflow branch.

Jann Horn reported that he can overflow the page ref count with
sufficient memory (and a filesystem that is intentionally extremely
slow).

Admittedly it's not exactly easy.  To have more than four billion
references to a page requires a minimum of 32GB of kernel memory just
for the pointers to the pages, much less any metadata to keep track of
those pointers.  Jann needed a total of 140GB of memory and a specially
crafted filesystem that leaves all reads pending (in order to not ever
free the page references and just keep adding more).

Still, we have a fairly straightforward way to limit the two obvious
user-controllable sources of page references: direct-IO like page
references gotten through get_user_pages(), and the splice pipe page
duplication.  So let's just do that.

* branch page-refs:
  fs: prevent page refcount overflow in pipe_buf_get
  mm: prevent get_user_pages() from overflowing page refcount
  mm: add 'try_get_page()' helper function
  mm: make page ref count overflow check tighter and more explicit

fs: prevent page refcount overflow in pipe_buf_get

2019-04-14T17:00:04+00:00

Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount.  All
callers converted to handle a failure.

Reported-by: Jann Horn 
Signed-off-by: Matthew Wilcox 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

Merge tag 'fuse-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2019-03-12T21:46:26+00:00

Pull fuse updates from Miklos Szeredi:
 "Scalability and performance improvements, as well as minor bug fixes
  and cleanups"

* tag 'fuse-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (25 commits)
  fuse: cache readdir calls if filesystem opts out of opendir
  fuse: support clients that don't implement 'opendir'
  fuse: lift bad inode checks into callers
  fuse: multiplex cached/direct_io file operations
  fuse add copy_file_range to direct io fops
  fuse: use iov_iter based generic splice helpers
  fuse: Switch to using async direct IO for FOPEN_DIRECT_IO
  fuse: use atomic64_t for khctr
  fuse: clean up aborted
  fuse: Protect ff->reserved_req via corresponding fi->lock
  fuse: Protect fi->nlookup with fi->lock
  fuse: Introduce fi->lock to protect write related fields
  fuse: Convert fc->attr_version into atomic64_t
  fuse: Add fuse_inode argument to fuse_prepare_release()
  fuse: Verify userspace asks to requeue interrupt that we really sent
  fuse: Do some refactoring in fuse_dev_do_write()
  fuse: Wake up req->waitq of only if not background
  fuse: Optimize request_end() by not taking fiq->waitq.lock
  fuse: Kill fasync only if interrupt is queued in queue_interrupt()
  fuse: Remove stale comment in end_requests()
  ...

mm: refactor readahead defines in mm.h

2019-03-12T17:04:01+00:00

All users of VM_MAX_READAHEAD actually convert it to kbytes and then to
pages. Define the macro explicitly as (SZ_128K / PAGE_SIZE). This
simplifies the expression in every filesystem. Also rename the macro to
VM_READAHEAD_PAGES to properly convey its meaning. Finally remove unused
VM_MIN_READAHEAD

[akpm@linux-foundation.org: fix fs/io_uring.c, per Stephen]
Link: http://lkml.kernel.org/r/20181221144053.24318-1-nborisov@suse.com
Signed-off-by: Nikolay Borisov 
Reviewed-by: Matthew Wilcox 
Reviewed-by: David Hildenbrand 
Cc: Jens Axboe 
Cc: Eric Van Hensbergen 
Cc: Latchesar Ionkov 
Cc: Dominique Martinet 
Cc: David Howells 
Cc: Chris Mason 
Cc: Josef Bacik 
Cc: David Sterba 
Cc: Miklos Szeredi 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

fuse: cache readdir calls if filesystem opts out of opendir

2019-02-13T12:15:15+00:00

If a filesystem returns ENOSYS from opendir and thus opts out of
opendir and releasedir requests, it almost certainly would also like
readdir results cached. Default open_flags to FOPEN_KEEP_CACHE and
FOPEN_CACHE_DIR in that case.

With this patch, I've measured recursive directory enumeration across
large FUSE mounts to be faster than native mounts.

Signed-off-by: Chad Austin 
Signed-off-by: Miklos Szeredi

fuse: support clients that don't implement 'opendir'

2019-02-13T12:15:15+00:00

Allow filesystems to return ENOSYS from opendir, preventing the kernel from
sending opendir and releasedir messages in the future. This avoids
userspace transitions when filesystems don't need to keep track of state
per directory handle.

A new capability flag, FUSE_NO_OPENDIR_SUPPORT, parallels
FUSE_NO_OPEN_SUPPORT, indicating the new semantics for returning ENOSYS
from opendir.

Signed-off-by: Chad Austin 
Signed-off-by: Miklos Szeredi

fuse: lift bad inode checks into callers

2019-02-13T12:15:15+00:00

Bad inode checks were done  done in various places, and move them into
fuse_file_{read|write}_iter().

Signed-off-by: Miklos Szeredi