Implement BRT (Block Reference Table) prefetch functionality similar
to existing DDT prefetch. This allows preloading BRT metadata into
ARC to improve performance for block cloning operations and frees
of earlier cloned blocks.
Make -t parameter optional. When omitted, prefetch all supported
metadata types (both DDT and BRT now).
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes#17890
This gives `zdb -b` support for clone blocks.
Previously, it didn't know what clones were, so would count their space
allocation multiple times and then report leaked space (or, in debug,
would assert trying to claim blocks a second time).
This commit fixes those bugs, and reports the number of clones and the
space "used" (saved) by them.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-By: OpenDrives Inc.
Sponsored-By: Klara Inc.
Closes#15123
Block Cloning allows to manually clone a file (or a subset of its
blocks) into another (or the same) file by just creating additional
references to the data blocks without copying the data itself.
Those references are kept in the Block Reference Tables (BRTs).
The whole design of block cloning is documented in module/zfs/brt.c.
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Christian Schwarz <christian.schwarz@nutanix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Rich Ercolani <rincebrain@gmail.com>
Signed-off-by: Pawel Jakub Dawidek <pawel@dawidek.net>
Closes#13392
Alexander Motin