DMU_BACKUP_FEATURE: indicate that bit 28 and 29 are reserved

Bit 28 is used by an internal Nutanix feature which might be upstreamed in the future. Bit 29 is the last unused bit. It is reserved to indicate a to-be-designed extension to the stream format which will accomodate more feature flags. Reviewed-by: Tino Reichardt <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Christian Schwarz <[email protected]> Issue openzfs#13795 Closes openzfs#13796
rrevans · Sep 27, 2022 · e872ea1 · e872ea1
1 parent 5c96663
commit e872ea1
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/include/sys/zfs_ioctl.h b/include/sys/zfs_ioctl.h
@@ -124,6 +124,13 @@ typedef enum drr_headertype {
  * default use of "zfs send" won't encounter the bug mentioned above.
  */
 #define	DMU_BACKUP_FEATURE_SWITCH_TO_LARGE_BLOCKS (1 << 27)
+/* flag #28 is reserved for a Nutanix feature */
+/*
+ * flag #29 is the last unused bit. It is reserved to indicate a to-be-designed
+ * extension to the stream format which will accomodate more feature flags.
+ * If you need to add another feature flag, please reach out to the OpenZFS
+ * community, e.g., on GitHub or Slack.
+ */
 
 /*
  * Mask of all supported backup features