MFV r350896: 6585 sha512, skein, and edonr have an unenforced dependency on extensible dataset
In any pool without the extensible dataset feature flag already enabled, creating a dataset with dedup set to use one of the new checksums would result in the following panic as soon as any data was added: panic[cpu0]/thread=ffffff0006761c40: feature_get_refcount(spa, feature, &refcount) != 48 (0x30 != 0x30), file: ../../common/fs/zfs/zfeature.c line 390 ffffff0006761830 fffffffffba8fbdd () ffffff0006761890 zfs:feature_do_action+11a () ffffff00067618c0 zfs:spa_feature_incr+1e () ffffff0006761920 zfs:dmu_object_zapify+b7 () ffffff00067619b0 zfs:dsl_dataset_activate_feature+97 () ffffff0006761a20 zfs:dsl_dataset_sync+ba () ffffff0006761ab0 zfs:dsl_pool_sync+153 () ffffff0006761b70 zfs:spa_sync+26e () ffffff0006761c20 zfs:txg_sync_thread+227 () ffffff0006761c30 unix:thread_start+8 () Inspection showed that feature->fi_feature was 7, which is the value of SPA_FEATURE_EXTENSIBLE_DATASET in the spa_feature enum. Testing shows that the panic can be prevented by explicitly setting extensible dataset as a dependency for the sha512, edonr, and skein feature flags. Alternatively, the new checksums code could possibly be changed to obviate the need for the dependency.
Reviewed by: Matthew Ahrens <firstname.lastname@example.org>
Reviewed by: Richard Laager <email@example.com>
Approved by: Robert Mustacchi <firstname.lastname@example.org>
Author: ilovezfs <email@example.com>
Note that FreeBSD does not support ednor yet.
MFC after: 2 weeks