linux-stable.git/fs/fuse/dev.c, branch v4.14.78

fuse: umount should wait for all requests

2018-09-05T07:26:38+00:00

commit b8f95e5d13f5f0191dcb4b9113113d241636e7cb upstream.

fuse_abort_conn() does not guarantee that all async requests have actually
finished aborting (i.e. their ->end() function is called).  This could
actually result in still used inodes after umount.

Add a helper to wait until all requests are fully done.  This is done by
looking at the "num_waiting" counter.  When this counter drops to zero, we
can be sure that no more requests are outstanding.

Fixes: 0d8e84b0432b ("fuse: simplify request abort")
Cc:  # v4.2
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix unlocked access to processing queue

2018-09-05T07:26:38+00:00

commit 45ff350bbd9d0f0977ff270a0d427c71520c0c37 upstream.

fuse_dev_release() assumes that it's the only one referencing the
fpq->processing list, but that's not true, since fuse_abort_conn() can be
doing the same without any serialization between the two.

Fixes: c3696046beb3 ("fuse: separate pqueue for clones")
Cc:  # v4.2
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix double request_end()

2018-09-05T07:26:38+00:00

commit 87114373ea507895a62afb10d2910bd9adac35a8 upstream.

Refcounting of request is broken when fuse_abort_conn() is called and
request is on the fpq->io list:

 - ref is taken too late
 - then it is not dropped

Fixes: 0d8e84b0432b ("fuse: simplify request abort")
Cc:  # v4.2
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: Don't access pipe->buffers without pipe_lock()

2018-09-05T07:26:37+00:00

commit a2477b0e67c52f4364a47c3ad70902bc2a61bd4c upstream.

fuse_dev_splice_write() reads pipe->buffers to determine the size of
'bufs' array before taking the pipe_lock(). This is not safe as
another thread might change the 'pipe->buffers' between the allocation
and taking the pipe_lock(). So we end up with too small 'bufs' array.

Move the bufs allocations inside pipe_lock()/pipe_unlock() to fix this.

Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device")
Signed-off-by: Andrey Ryabinin 
Cc:  # v2.6.35
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix congested state leak on aborted connections

2018-07-03T09:24:49+00:00

commit 8a301eb16d99983a4961f884690ec97b92e7dcfe upstream.

If a connection gets aborted while congested, FUSE can leave
nr_wb_congested[] stuck until reboot causing wait_iff_congested() to
wait spuriously which can lead to severe performance degradation.

The leak is caused by gating congestion state clearing with
fc->connected test in request_end().  This was added way back in 2009
by 26c3679101db ("fuse: destroy bdi on umount").  While the commit
description doesn't explain why the test was added, it most likely was
to avoid dereferencing bdi after it got destroyed.

Since then, bdi lifetime rules have changed many times and now we're
always guaranteed to have access to the bdi while the superblock is
alive (fc->sb).

Drop fc->connected conditional to avoid leaking congestion states.

Signed-off-by: Tejun Heo 
Reported-by: Joshua Miller 
Cc: Johannes Weiner 
Cc: stable@vger.kernel.org # v2.6.29+
Acked-by: Jan Kara 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: allow server to run in different pid_ns

2017-09-12T14:57:53+00:00

Commit 0b6e9ea041e6 ("fuse: Add support for pid namespaces") broke
Sandstorm.io development tools, which have been sending FUSE file
descriptors across PID namespace boundaries since early 2014.

The above patch added a check that prevented I/O on the fuse device file
descriptor if the pid namespace of the reader/writer was different from the
pid namespace of the mounter.  With this change passing the device file
descriptor to a different pid namespace simply doesn't work.  The check was
added because pids are transferred to/from the fuse userspace server in the
namespace registered at mount time.

To fix this regression, remove the checks and do the following:

1) the pid in the request header (the pid of the task that initiated the
filesystem operation) is translated to the reader's pid namespace.  If a
mapping doesn't exist for this pid, then a zero pid is used.  Note: even if
a mapping would exist between the initiator task's pid namespace and the
reader's pid namespace the pid will be zero if either mapping from
initator's to mounter's namespace or mapping from mounter's to reader's
namespace doesn't exist.

2) The lk.pid value in setlk/setlkw requests and getlk reply is left alone.
Userspace should not interpret this value anyway.  Also allow the
setlk/setlkw operations if the pid of the task cannot be represented in the
mounter's namespace (pid being zero in that case).

Reported-by: Kenton Varda 
Signed-off-by: Miklos Szeredi 
Fixes: 0b6e9ea041e6 ("fuse: Add support for pid namespaces")
Cc:  # v4.12+
Cc: Eric W. Biederman 
Cc: Seth Forshee

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

2017-05-10T15:45:30+00:00

Pull fuse updates from Miklos Szeredi:
 "Support for pid namespaces from Seth and refcount_t work from Elena"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: Add support for pid namespaces
  fuse: convert fuse_conn.count from atomic_t to refcount_t
  fuse: convert fuse_req.count from atomic_t to refcount_t
  fuse: convert fuse_file.count from atomic_t to refcount_t

fuse: Get rid of bdi_initialized

2017-04-20T18:09:55+00:00

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

CC: Miklos Szeredi 
CC: linux-fsdevel@vger.kernel.org
Suggested-by: Miklos Szeredi 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe

fuse: Convert to separately allocated bdi

2017-04-20T18:09:55+00:00

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

CC: Miklos Szeredi 
CC: linux-fsdevel@vger.kernel.org
Acked-by: Miklos Szeredi 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
Signed-off-by: Jens Axboe

fuse: Add support for pid namespaces

2017-04-18T14:58:38+00:00

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: Seth Forshee 
Signed-off-by: Miklos Szeredi