Fix handling of maxblkid for raw sends

Currently, the receive code can create an unreadable dataset from
a correct raw send stream. This is because it is currently
impossible to set maxblkid to a lower value without freeing the
associated object. This means truncating files on the send side
to a non-0 size could result in corruption. This patch solves this
issue by adding a new 'force' flag to dnode_new_blkid() which will
allow the raw receive code to force the DMU to accept the provided
maxblkid even if it is a lower value than the existing one.

For testing purposes the send_encrypted_files.ksh test has been
extended to include a variety of truncated files and multiple
snapshots. It also now leverages the xattrtest command to help
ensure raw receives correctly handle xattrs.

Reviewed-by: Paul Dagnelie <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Matt Ahrens <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #8168 
Closes #8487 

1 files changed, 5 insertions, 8 deletions

diff --git a/module/zfs/dnode_sync.c b/module/zfs/dnode_sync.c
index c4062beb3..581f812a1 100644
--- a/module/zfs/dnode_sync.c
+++ b/module/zfs/dnode_sync.c
@@ -384,12 +384,7 @@ dnode_sync_free_range_impl(dnode_t *dn, uint64_t blkid, uint64_t nblks,
 		}
 	}
 
-	/*
-	 * Do not truncate the maxblkid if we are performing a raw
-	 * receive. The raw receive sets the mablkid manually and
-	 * must not be overriden.
-	 */
-	if (trunc && !dn->dn_objset->os_raw_receive) {
+	if (trunc) {
 		ASSERTV(uint64_t off);
 		dn->dn_phys->dn_maxblkid = blkid == 0 ? 0 : blkid - 1;
 
@@ -765,11 +760,13 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 
 	/*
 	 * This must be done after dnode_sync_free_range()
-	 * and dnode_increase_indirection().
+	 * and dnode_increase_indirection(). See dnode_new_blkid()
+	 * for an explanation of the high bit being set.
 	 */
 	if (dn->dn_next_maxblkid[txgoff]) {
 		mutex_enter(&dn->dn_mtx);
-		dnp->dn_maxblkid = dn->dn_next_maxblkid[txgoff];
+		dnp->dn_maxblkid =
+		    dn->dn_next_maxblkid[txgoff] & ~DMU_NEXT_MAXBLKID_SET;
 		dn->dn_next_maxblkid[txgoff] = 0;
 		mutex_exit(&dn->dn_mtx);
 	}