tree 6b727eabcb415cb66e64dc48ba4ae0887cddc2e7
parent c54854a437a447a6bb1dcb11f60dd01cef3fa597
author Darrick J. Wong <darrick.wong@oracle.com> 1512957834 -0800
committer Darrick J. Wong <darrick.wong@oracle.com> 1513272011 -0800

xfs: remove dest file's post-eof preallocations before reflinking

If we try to reflink into a file with post-eof preallocations at an
offset well past the preallocations, we increase i_size as one would
expect.  However, those allocations do not have page cache backing them,
so they won't get cleaned out on their own.  This leads to asserts in
the collapse/insert range code and xfs_destroy_inode when they encounter
delalloc extents they weren't expecting to find.

Since there are plenty of other places where we dump those post-eof
blocks, do the same to the reflink destination file before we start
remapping extents.  This was found by adding clonerange support to
fsstress and running it in write-only mode.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>