Add snapshots_changed as property

Make dd_snap_cmtime property persistent across mount and unmount
operations by storing in ZAP and restore the value from ZAP on hold
into dd_snap_cmtime instead of updating it.

Expose dd_snap_cmtime as 'snapshots_changed' property that provides a
mechanism to quickly determine whether snapshot list for dataset has
changed without having to mount a dataset or iterate the snapshot list.

It specifies the time at which a snapshot for a dataset was last
created or deleted. This allows us to be more efficient how often we
query snapshots.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #13635

This commit is contained in:

Umer Saleem

2022-08-03 04:45:30 +05:00

committed by

GitHub

parent 5ad44a0ce9

commit 9681de4657

14 changed files with 203 additions and 9 deletions

lib/libzfs/libzfs.abi

+2 -1

View File

@@ -2398,7 +2398,8 @@
       <enumerator name='ZFS_PROP_IVSET_GUID' value='92'/>
       <enumerator name='ZFS_PROP_REDACTED' value='93'/>
       <enumerator name='ZFS_PROP_REDACT_SNAPS' value='94'/>
       <enumerator name='ZFS_NUM_PROPS' value='95'/>
       <enumerator name='ZFS_PROP_SNAPSHOTS_CHANGED' value='95'/>
       <enumerator name='ZFS_NUM_PROPS' value='96'/>
     </enum-decl>
     <typedef-decl name='zfs_prop_t' type-id='4b000d60' id='58603c44'/>
     <enum-decl name='zfs_userquota_prop_t' naming-typedef-id='279fde6a' id='5258d2f6'>