commit b8a8684502a0fc852afa0056c6bb2a9273f6fcc0
author Lukas Czerner <lczerner@redhat.com> Tue Mar 18 18:05:35 2014 -0400
committer Theodore Ts'o <tytso@mit.edu> Tue Mar 18 18:05:35 2014 -0400
tree 3b7c2058c86f5247a31e02e1a04182c40775e268
parent 0e8b6879f3c234036181526683be2b0231892ae4

ext4: Introduce FALLOC_FL_ZERO_RANGE flag for fallocate

Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same
functionality as xfs ioctl XFS_IOC_ZERO_RANGE.

It can be used to convert a range of file to zeros preferably without
issuing data IO. Blocks should be preallocated for the regions that span
holes in the file, and the entire range is preferable converted to
unwritten extents

This can be also used to preallocate blocks past EOF in the same way as
with fallocate. Flag FALLOC_FL_KEEP_SIZE which should cause the inode
size to remain the same.

Also add appropriate tracepoints.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>