SEEK_HOLE and SEEK_DATA¶

When building a Yocto image, I came across an error:

wic.filemap.ErrorNotSupp: the file-system does not support "SEEK_HOLE" and "SEEK_DATA" but only provides a stub implementation

The relevant discussion is on github.com/openzfs/zfs#6958.

It seems that it may also be worth investigating the zfs_dmu_offset_next_sync parameter, see bmap-tools/README.

Path: /sys/module/zfs/parameters/zfs_dmu_offset_next_sync

zfs_dmu_offset_next_sync (int)¶

Enable forcing txg sync to find holes. When enabled forces ZFS to act like prior versions when SEEK_HOLE or SEEK_DATA flags are used, which when a dnode is dirty causes txg's to be synced so that this data can be found.

Use 1 for yes and 0 to disable (default).