Mention that FICLONE, FICLONERANGE, and FIDEDUPERANGE all require
both files to reside on the same filesystem.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
.I dest_fd
file by sharing the underlying storage, which is faster than making a separate
physical copy of the data.
+Both files must reside within the same filesystem.
If a file write should occur to a shared region,
the filesystem must ensure that the changes remain private to the file being
written.
.B dest_fd
file by sharing the underlying storage if the file data is identical
("deduplication").
+Both files must reside within the same filesystem.
This reduces storage consumption by allowing the filesystem
to store one shared copy of the data.
If a file write should occur to a shared