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 

2 files changed, 10 insertions, 2 deletions

diff --git a/include/sys/dmu.h b/include/sys/dmu.h
index e4c2ebc2f..93d05aac4 100644
--- a/include/sys/dmu.h
+++ b/include/sys/dmu.h
@@ -477,7 +477,8 @@ int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
 
 /*
  * Manually set the maxblkid on a dnode. This will adjust nlevels accordingly
- * to accommodate the change.
+ * to accommodate the change. When calling this function, the caller must
+ * ensure that the object's nlevels can sufficiently support the new maxblkid.
  */
 int dmu_object_set_maxblkid(objset_t *os, uint64_t object, uint64_t maxblkid,
     dmu_tx_t *tx);
diff --git a/include/sys/dnode.h b/include/sys/dnode.h
index 48ef927d4..6355aaa50 100644
--- a/include/sys/dnode.h
+++ b/include/sys/dnode.h
@@ -372,6 +372,12 @@ struct dnode {
 };
 
 /*
+ * We use this (otherwise unused) bit to indicate if the value of
+ * dn_next_maxblkid[txgoff] is valid to use in dnode_sync().
+ */
+#define	DMU_NEXT_MAXBLKID_SET		(1ULL << 63)
+
+/*
  * Adds a level of indirection between the dbuf and the dnode to avoid
  * iterating descendent dbufs in dnode_move(). Handles are not allocated
  * individually, but as an array of child dnodes in dnode_hold_impl().
@@ -423,7 +429,8 @@ int dnode_set_nlevels(dnode_t *dn, int nlevels, dmu_tx_t *tx);
 int dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx);
 void dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx);
 void dnode_diduse_space(dnode_t *dn, int64_t space);
-void dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t);
+void dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx,
+    boolean_t have_read, boolean_t force);
 uint64_t dnode_block_freed(dnode_t *dn, uint64_t blkid);
 void dnode_init(void);
 void dnode_fini(void);