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authorTom Caputi <tcaputi@datto.com>2018-06-18 17:10:54 -0400
committerBrian Behlendorf <behlendorf1@llnl.gov>2018-06-18 14:10:54 -0700
commitcd32e5db8bb4411533dc21cfc12a5af5f3b56701 (patch)
tree4e0d5b1cda63b2c5603c3995c066aaf2ffcea200 /module/zfs
parent517d2471921fc44622dc737b09b655829b8c9c6f (diff)
Add ASSERT to debug encryption key mapping issues
This patch simply adds an ASSERT that confirms that the last decrypting reference on a dataset waits until the dataset is no longer dirty. This should help to debug issues where the ZIO layer cannot find encryption keys after a dataset has been disowned. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Tom Caputi <tcaputi@datto.com> Closes #7637
Diffstat (limited to 'module/zfs')
-rw-r--r--module/zfs/dbuf.c14
-rw-r--r--module/zfs/dsl_dataset.c9
2 files changed, 23 insertions, 0 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 2411c8d4f..e3738db52 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -3306,6 +3306,20 @@ dbuf_refcount(dmu_buf_impl_t *db)
return (refcount_count(&db->db_holds));
}
+uint64_t
+dmu_buf_user_refcount(dmu_buf_t *db_fake)
+{
+ uint64_t holds;
+ dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
+
+ mutex_enter(&db->db_mtx);
+ ASSERT3U(refcount_count(&db->db_holds), >=, db->db_dirtycnt);
+ holds = refcount_count(&db->db_holds) - db->db_dirtycnt;
+ mutex_exit(&db->db_mtx);
+
+ return (holds);
+}
+
void *
dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user,
dmu_buf_user_t *new_user)
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index 7a4721e17..9db6d1e0b 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -791,6 +791,15 @@ dsl_dataset_rele_flags(dsl_dataset_t *ds, ds_hold_flags_t flags, void *tag)
(flags & DS_HOLD_FLAG_DECRYPT)) {
(void) spa_keystore_remove_mapping(ds->ds_dir->dd_pool->dp_spa,
ds->ds_object, ds);
+
+ /*
+ * Encrypted datasets require that users only release their
+ * decrypting reference after the dirty data has actually
+ * been written out. This ensures that the mapping exists
+ * when it is needed to write out dirty data.
+ */
+ ASSERT(dmu_buf_user_refcount(ds->ds_dbuf) != 0 ||
+ !dsl_dataset_is_dirty(ds));
}
dmu_buf_rele(ds->ds_dbuf, tag);