linux-stable.git/fs/fuse/file.c, branch linux-5.0.y

fuse: Add FOPEN_STREAM to use stream_open()

2019-05-25T16:22:20+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

2019-05-25T16:22:09+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

2019-05-25T16:22:09+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

fuse: decrement NR_WRITEBACK_TEMP on the right page

2019-01-16T09:27:59+00:00

NR_WRITEBACK_TEMP is accounted on the temporary page in the request, not
the page cache page.

Fixes: 8b284dc47291 ("fuse: writepages: handle same page rewrites")
Cc:  # v3.13
Signed-off-by: Miklos Szeredi

fuse: continue to send FUSE_RELEASEDIR when FUSE_OPEN returns ENOSYS

2018-12-11T20:47:28+00:00

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: 7678ac50615d ("fuse: support clients that don't implement 'open'")
Cc:  # v3.14
Signed-off-by: Chad Austin 
Signed-off-by: Miklos Szeredi

fuse: fix fsync on directory

2018-12-03T09:14:43+00:00

Commit ab2257e9941b ("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 
Tested-by: Brett Girton 
Fixes: ab2257e9941b ("fuse: reduce size of struct fuse_inode")
Signed-off-by: Miklos Szeredi

fuse: fix use-after-free in fuse_direct_IO()

2018-11-09T14:52:17+00:00

In async IO blocking case the additional reference to the io is taken for
it to survive fuse_aio_complete(). In non blocking case this additional
reference is not needed, however we still reference io to figure out
whether to wait for completion or not. This is wrong and will lead to
use-after-free. Fix it by storing blocking information in separate
variable.

This was spotted by KASAN when running generic/208 fstest.

Signed-off-by: Lukas Czerner 
Reported-by: Zorro Lang 
Signed-off-by: Miklos Szeredi 
Fixes: 744742d692e3 ("fuse: Add reference counting for fuse_io_priv")
Cc:  # v4.6

Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-11-02T02:58:52+00:00

Pull AFS updates from Al Viro:
 "AFS series, with some iov_iter bits included"

* 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  missing bits of "iov_iter: Separate type from direction and use accessor functions"
  afs: Probe multiple fileservers simultaneously
  afs: Fix callback handling
  afs: Eliminate the address pointer from the address list cursor
  afs: Allow dumping of server cursor on operation failure
  afs: Implement YFS support in the fs client
  afs: Expand data structure fields to support YFS
  afs: Get the target vnode in afs_rmdir() and get a callback on it
  afs: Calc callback expiry in op reply delivery
  afs: Fix FS.FetchStatus delivery from updating wrong vnode
  afs: Implement the YFS cache manager service
  afs: Remove callback details from afs_callback_break struct
  afs: Commit the status on a new file/dir/symlink
  afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS
  afs: Don't invoke the server to read data beyond EOF
  afs: Add a couple of tracepoints to log I/O errors
  afs: Handle EIO from delivery function
  afs: Fix TTL on VL server and address lists
  afs: Implement VL server rotation
  afs: Improve FS server rotation error handling
  ...

iov_iter: Use accessor function

2018-10-23T23:40:44+00:00

Use accessor functions to access an iterator's type and direction.  This
allows for the possibility of using some other method of determining the
type of iterator than if-chains with bitwise-AND conditions.

Signed-off-by: David Howells

fuse: only invalidate atime in direct read

2018-10-15T13:43:06+00:00

After sending a synchronous READ request from __fuse_direct_read() we only
need to invalidate atime; none of the other attributes should be changed by
a read().

Signed-off-by: Miklos Szeredi