copy-in: for files, only iterate file blocks that are mapped
Rewrite the file copy-in algorithm to detect smaller holes in the
files we're copying in. Use SEEK_DATA/SEEK_HOLE/FIEMAP when available
to skip known empty parts. This fixes the particular bug where zeroed
blocks on a system with 64k pages are needlessly copied into a
4k-block filesystem. It also saves time by skipping parts we know to
be zeroed.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed