Merge tag 'xfs-4.12-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Darrick Wong:
 "Here are the XFS changes for 4.12. The big new feature for this
  release is the new space mapping ioctl that we've been discussing
  since LSF2016, but other than that most of the patches are larger bug
  fixes, memory corruption prevention, and other cleanups.

  Summary:
   - various code cleanups
   - introduce GETFSMAP ioctl
   - various refactoring
   - avoid dio reads past eof
   - fix memory corruption and other errors with fragmented directory blocks
   - fix accidental userspace memory corruptions
   - publish fs uuid in superblock
   - make fstrim terminatable
   - fix race between quotaoff and in-core inode creation
   - avoid use-after-free when finishing up w/ buffer heads
   - reserve enough space to handle bmap tree resizing during cow remap"

* tag 'xfs-4.12-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (53 commits)
  xfs: fix use-after-free in xfs_finish_page_writeback
  xfs: reserve enough blocks to handle btree splits when remapping
  xfs: wait on new inodes during quotaoff dquot release
  xfs: update ag iterator to support wait on new inodes
  xfs: support ability to wait on new inodes
  xfs: publish UUID in struct super_block
  xfs: Allow user to kill fstrim process
  xfs: better log intent item refcount checking
  xfs: fix up quotacheck buffer list error handling
  xfs: remove xfs_trans_ail_delete_bulk
  xfs: don't use bool values in trace buffers
  xfs: fix getfsmap userspace memory corruption while setting OF_LAST
  xfs: fix __user annotations for xfs_ioc_getfsmap
  xfs: corruption needs to respect endianess too!
  xfs: use NULL instead of 0 to initialize a pointer in xfs_ioc_getfsmap
  xfs: use NULL instead of 0 to initialize a pointer in xfs_getfsmap
  xfs: simplify validation of the unwritten extent bit
  xfs: remove unused values from xfs_exntst_t
  xfs: remove the unused XFS_MAXLINK_1 define
  xfs: more do_div cleanups
  ...

1 files changed, 24 insertions, 0 deletions

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index ca09061..62fa392 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1079,6 +1079,8 @@ void
 xfs_buf_unlock(
 	struct xfs_buf		*bp)
 {
+	ASSERT(xfs_buf_islocked(bp));
+
 	XB_CLEAR_OWNER(bp);
 	up(&bp->b_sema);
 
@@ -1815,6 +1817,28 @@ error:
 }
 
 /*
+ * Cancel a delayed write list.
+ *
+ * Remove each buffer from the list, clear the delwri queue flag and drop the
+ * associated buffer reference.
+ */
+void
+xfs_buf_delwri_cancel(
+	struct list_head	*list)
+{
+	struct xfs_buf		*bp;
+
+	while (!list_empty(list)) {
+		bp = list_first_entry(list, struct xfs_buf, b_list);
+
+		xfs_buf_lock(bp);
+		bp->b_flags &= ~_XBF_DELWRI_Q;
+		list_del_init(&bp->b_list);
+		xfs_buf_relse(bp);
+	}
+}
+
+/*
  * Add a buffer to the delayed write list.
  *
  * This queues a buffer for writeout if it hasn't already been.  Note that