• Darrick J. Wong's avatar
    xfs: create a separate cow extent size hint for the allocator · f7ca3522
    Darrick J. Wong authored
    Create a per-inode extent size allocator hint for copy-on-write.  This
    hint is separate from the existing extent size hint so that CoW can
    take advantage of the fragmentation-reducing properties of extent size
    hints without disabling delalloc for regular writes.
    
    The extent size hint that's fed to the allocator during a copy on
    write operation is the greater of the cowextsize and regular extsize
    hint.
    
    During reflink, if we're sharing the entire source file to the entire
    destination file and the destination file doesn't already have a
    cowextsize hint, propagate the source file's cowextsize hint to the
    destination file.
    
    Furthermore, zero the bulkstat buffer prior to setting the fields
    so that we don't copy kernel memory contents into userspace.
    Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    f7ca3522
xfs_inode.h 14.7 KB