linux-toradex.git/fs, branch v3.17-rc2

Merge tag 'nfs-for-3.17-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

2014-08-25T22:34:28+00:00

Pull NFS client fixes from Trond Myklebust:
 "Highlights:

   - more fixes for read/write codepath regressions
     * sleeping while holding the inode lock
     * stricter enforcement of page contiguity when coalescing requests
     * fix up error handling in the page coalescing code

   - don't busy wait on SIGKILL in the file locking code"

* tag 'nfs-for-3.17-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs: Don't busy-wait on SIGKILL in __nfs_iocounter_wait
  nfs: can_coalesce_requests must enforce contiguity
  nfs: disallow duplicate pages in pgio page vectors
  nfs: don't sleep with inode lock in lock_and_join_requests
  nfs: fix error handling in lock_and_join_requests
  nfs: use blocking page_group_lock in add_request
  nfs: fix nonblocking calls to nfs_page_group_lock
  nfs: change nfs_page_group_lock argument

aio: fix reqs_available handling

2014-08-24T22:47:27+00:00

As reported by Dan Aloni, commit f8567a3845ac ("aio: fix aio request
leak when events are reaped by userspace") introduces a regression when
user code attempts to perform io_submit() with more events than are
available in the ring buffer.  Reverting that commit would reintroduce a
regression when user space event reaping is used.

Fixing this bug is a bit more involved than the previous attempts to fix
this regression.  Since we do not have a single point at which we can
count events as being reaped by user space and io_getevents(), we have
to track event completion by looking at the number of events left in the
event ring.  So long as there are as many events in the ring buffer as
there have been completion events generate, we cannot call
put_reqs_available().  The code to check for this is now placed in
refill_reqs_available().

A test program from Dan and modified by me for verifying this bug is available
at http://www.kvack.org/~bcrl/20140824-aio_bug.c .

Reported-by: Dan Aloni 
Signed-off-by: Benjamin LaHaise 
Acked-by: Dan Aloni 
Cc: Kent Overstreet 
Cc: Mateusz Guzik 
Cc: Petr Matousek 
Cc: stable@vger.kernel.org      # v3.16 and anything that f8567a3845ac was backported to
Signed-off-by: Linus Torvalds

nfs: Don't busy-wait on SIGKILL in __nfs_iocounter_wait

2014-08-22T22:04:44+00:00

If a SIGKILL is sent to a task waiting in __nfs_iocounter_wait,
it will busy-wait or soft lockup in its while loop.
nfs_wait_bit_killable won't sleep, and the loop won't exit on
the error return.

Stop the busy-wait by breaking out of the loop when
nfs_wait_bit_killable returns an error.

Signed-off-by: David Jeffery 
Signed-off-by: Trond Myklebust

nfs: can_coalesce_requests must enforce contiguity

2014-08-22T22:04:44+00:00

Commit 6094f83864c1d1296566a282cba05ba613f151ee
"nfs: allow coalescing of subpage requests" got rid of the requirement
that requests cover whole pages, but it made some incorrect assumptions.

It turns out that callers of this interface can map adjacent requests
(by file position as seen by req_offset + req->wb_bytes) to different pages,
even when they could share a page. An example is the direct I/O interface -
iov_iter_get_pages_alloc may return one segment with a partial page filled
and the next segment (which is adjacent in the file position) starts with a
new page.

Reported-by: Toralf Förster 
Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: disallow duplicate pages in pgio page vectors

2014-08-22T22:04:44+00:00

Adjacent requests that share the same page are allowed, but should only
use one entry in the page vector. This avoids overruning the page
vector - it is sized based on how many bytes there are, not by
request count.

This fixes issues that manifest as "Redzone overwritten" bugs (the
vector overrun) and hangs waiting on page read / write, as it waits on
the same page more than once.

This also adds bounds checking to the page vector with a graceful failure
(WARN_ON_ONCE and pgio error returned to application).

Reported-by: Toralf Förster 
Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

nfs: don't sleep with inode lock in lock_and_join_requests

2014-08-22T22:04:43+00:00

This handles the 'nonblock=false' case in nfs_lock_and_join_requests.
If the group is already locked and blocking is allowed, drop the inode lock
and wait for the group lock to be cleared before trying it all again.
This should fix warnings found in peterz's tree (sched/wait branch), where
might_sleep() checks are added to wait.[ch].

Reported-by: Fengguang Wu 
Signed-off-by: Weston Andros Adamson 
Reviewed-by: Peng Tao 
Signed-off-by: Trond Myklebust

nfs: fix error handling in lock_and_join_requests

2014-08-22T22:04:43+00:00

This fixes handling of errors from nfs_page_group_lock in
nfs_lock_and_join_requests.  It now releases the inode lock and the
reference to the head request.

Reported-by: Peng Tao 
Signed-off-by: Weston Andros Adamson 
Reviewed-by: Peng Tao 
Signed-off-by: Trond Myklebust

nfs: use blocking page_group_lock in add_request

2014-08-22T22:04:43+00:00

__nfs_pageio_add_request was calling nfs_page_group_lock nonblocking, but
this can return -EAGAIN which would end up passing -EIO to the application.

There is no reason not to block in this path, so change the two calls to
do so. Also, there is no need to check the return value of
nfs_page_group_lock when nonblock=false, so remove the error handling code.

Signed-off-by: Weston Andros Adamson 
Reviewed-by: Peng Tao 
Signed-off-by: Trond Myklebust

nfs: fix nonblocking calls to nfs_page_group_lock

2014-08-22T22:04:42+00:00

nfs_page_group_lock was calling wait_on_bit_lock even when told not to
block. Fix by first trying test_and_set_bit, followed by wait_on_bit_lock
if and only if blocking is allowed.  Return -EAGAIN if nonblocking and the
test_and_set of the bit was already locked.

Signed-off-by: Weston Andros Adamson 
Reviewed-by: Peng Tao 
Signed-off-by: Trond Myklebust

nfs: change nfs_page_group_lock argument

2014-08-22T22:04:42+00:00

Flip the meaning of the second argument from 'wait' to 'nonblock' to
match related functions. Update all five calls to reflect this change.

Signed-off-by: Weston Andros Adamson 
Reviewed-by: Peng Tao 
Signed-off-by: Trond Myklebust