[PATCH 3/3] xfs: cancel COW in xfs_cancel_ioend

[Christoph Hellwig]

On Mon, Jan 04, 2016 at 05:43:10PM -0800, Darrick J. Wong wrote:
> Hmm.  This might be the cause of the occasional complaints I've been seeing
> where allocated blocks remain in the COW fork when the inode is being cleared
> out.  That said, the xfs_reflink_end_cow_failed() is apparently missing a
> xfs_bunmapi_cow() to actually clean out the COW fork.

I can still reproduce xfs_reflink_cancel_pending_cow tripping over
allocated blocks in the COW fork over NFS.  generic/154 reproduces
it 100% over NFS, although when adding a delay before the cleanup
it disappears.  I'm currently trying to figure out why.