linux.git/fs/xfs, branch v4.8

xfs: track log done items directly in the deferred pending work item

2016-08-30T03:51:39+00:00

Christoph reports slab corruption when a deferred refcount update
aborts during _defer_finish().  The cause of this was broken log item
state tracking in xfs_defer_pending -- upon an abort,
_defer_trans_abort() will call abort_intent on all intent items,
including the ones that have already had a done item attached.

This is incorrect because each intent item has 2 refcount: the first
is released when the intent item is committed to the log; and the
second is released when the _done_ item is committed to the log, or
by the intent creator if there is no done item.  In other words, once
we log the done item, responsibility for releasing the intent item's
second refcount is transferred to the done item and /must not/ be
performed by anything else.

The dfp_committed flag should have been tracking whether or not we had
a done item so that _defer_trans_abort could decide if it needs to
abort the intent item, but due to a thinko this was not the case.  Rip
it out and track the done item directly so that we do the right thing
w.r.t. intent item freeing.

Signed-off-by: Darrick J. Wong 
Reported-by: Christoph Hellwig 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner

xfs: prevent dropping ioend completions during buftarg wait

2016-08-26T06:01:59+00:00

xfs_wait_buftarg() waits for all pending I/O, drains the ioend
completion workqueue and walks the LRU until all buffers in the cache
have been released. This is traditionally an unmount operation` but the
mechanism is also reused during filesystem freeze.

xfs_wait_buftarg() invokes drain_workqueue() as part of the quiesce,
which is intended more for a shutdown sequence in that it indicates to
the queue that new operations are not expected once the drain has begun.
New work jobs after this point result in a WARN_ON_ONCE() and are
otherwise dropped.

With filesystem freeze, however, read operations are allowed and can
proceed during or after the workqueue drain. If such a read occurs
during the drain sequence, the workqueue infrastructure complains about
the queued ioend completion work item and drops it on the floor. As a
result, the buffer remains on the LRU and the freeze never completes.

Despite the fact that the overall buffer cache cleanup is not necessary
during freeze, fix up this operation such that it is safe to invoke
during non-unmount quiesce operations. Replace the drain_workqueue()
call with flush_workqueue(), which runs a similar serialization on
pending workqueue jobs without causing new jobs to be dropped. This is
safe for unmount as unmount independently locks out new operations by
the time xfs_wait_buftarg() is invoked.

cc: 
Signed-off-by: Brian Foster 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: fix superblock inprogress check

2016-08-26T06:01:30+00:00

From inspection, the superblock sb_inprogress check is done in the
verifier and triggered only for the primary superblock via a
"bp->b_bn == XFS_SB_DADDR" check.

Unfortunately, the primary superblock is an uncached buffer, and
hence it is configured by xfs_buf_read_uncached() with:

	bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */

And so this check never triggers. Fix it.

cc: 
Signed-off-by: Dave Chinner 
Reviewed-by: Brian Foster 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: simple btree query range should look right if LE lookup fails

2016-08-26T06:00:10+00:00

If the initial LOOKUP_LE in the simple query range fails to find
anything, we should attempt to increment the btree cursor to see
if there actually /are/ records for what we're trying to find.
Without this patch, a bnobt range query of (0, $agsize) returns
no results because the leftmost record never has a startblock
of zero.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: fix some key handling problems in _btree_simple_query_range

2016-08-26T05:59:50+00:00

We only need the record's high key for the first record that we look
at; for all records, we /definitely/ need the regular record key.
Therefore, fix how the simple range query function gets its keys.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: don't log the entire end of the AGF

2016-08-26T05:59:31+00:00

When we're logging the last non-spare field in the AGF, we don't
need to log the spare fields, so plumb in a new AGF logging flag
to help us avoid that.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: disallow mounting of realtime + rmap filesystems

2016-08-26T05:59:19+00:00

Since the kernel doesn't currently support the realtime rmapbt,
don't allow such filesystems to be mounted.  Support will appear
in a future release.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Carlos Maiolino 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

xfs: don't perform lookups on zero-height btrees

2016-08-26T05:58:40+00:00

If the caller passes in a cursor to a zero-height btree (which is
impossible), we never set block to anything but NULL, which causes the
later dereference of it to crash.  Instead, just return -EFSCORRUPTED.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dave Chinner

Merge branch 'iomap-fixes-4.8-rc3' into for-next

2016-08-17T01:13:37+00:00

xfs: remove OWN_AG rmap when allocating a block from the AGFL

2016-08-17T01:12:57+00:00

When we're really tight on space, xfs_alloc_ag_vextent_small() can
allocate a block from the AGFL and give it to the caller.  Since the
caller is never the AGFL-fixing method, we must remove the OWN_AG
reverse mapping because it will clash with whatever rmap the caller
wants to set up.  This bug was discovered by running generic/299
repeatedly.

Signed-off-by: Darrick J. Wong 
Reviewed-by: Dave Chinner 
Signed-off-by: Dave Chinner