Fix OpenZFS 9337 mismerge

This change reintroduces logic required by OpenZFS 9577. When
OpenZFS 9337, zfs get all is slow due to uncached metadata, was
merged in it ended up removing logic required by OpenZFS 9577,
remove zfs_dbuf_evict_key, and inadvertently reintroduced the
bug that 9577 was designed to fix.

This change re-enables the "evicting" flag to dbuf_rele_and_unlock
and dnode_rele_and_unlock and updates all callers to provide the
correct parameter.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: George Wilson <[email protected]>
Closes #7758

3 files changed, 14 insertions, 13 deletions

diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index dad090bf9..2724f3aa2 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -1212,7 +1212,7 @@ dbuf_read_done(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
 		db->db_state = DB_UNCACHED;
 	}
 	cv_broadcast(&db->db_changed);
-	dbuf_rele_and_unlock(db, NULL);
+	dbuf_rele_and_unlock(db, NULL, B_FALSE);
 }
 
 
@@ -2580,7 +2580,7 @@ dbuf_destroy(dmu_buf_impl_t *db)
 		 * release any lock.
 		 */
 		mutex_enter(&dn->dn_mtx);
-		dnode_rele_and_unlock(dn, db);
+		dnode_rele_and_unlock(dn, db, B_TRUE);
 		db->db_dnode_handle = NULL;
 
 		dbuf_hash_remove(db);
@@ -2609,7 +2609,7 @@ dbuf_destroy(dmu_buf_impl_t *db)
 	 */
 	if (parent && parent != dndb) {
 		mutex_enter(&parent->db_mtx);
-		dbuf_rele_and_unlock(parent, db);
+		dbuf_rele_and_unlock(parent, db, B_TRUE);
 	}
 }
 
@@ -3351,7 +3351,7 @@ void
 dbuf_rele(dmu_buf_impl_t *db, void *tag)
 {
 	mutex_enter(&db->db_mtx);
-	dbuf_rele_and_unlock(db, tag);
+	dbuf_rele_and_unlock(db, tag, B_FALSE);
 }
 
 void
@@ -3374,7 +3374,7 @@ dmu_buf_rele(dmu_buf_t *db, void *tag)
  *
  */
 void
-dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
+dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag, boolean_t evicting)
 {
 	int64_t holds;
 
@@ -3495,7 +3495,8 @@ dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
 				}
 				mutex_exit(&db->db_mtx);
 
-				if (db->db_caching_status == DB_DBUF_CACHE) {
+				if (db->db_caching_status == DB_DBUF_CACHE &&
+				    !evicting) {
 					dbuf_evict_notify();
 				}
 			}
@@ -3848,7 +3849,7 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 		kmem_free(dr, sizeof (dbuf_dirty_record_t));
 		ASSERT(db->db_dirtycnt > 0);
 		db->db_dirtycnt -= 1;
-		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
+		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg, B_FALSE);
 		return;
 	}
 
@@ -4223,7 +4224,7 @@ dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
 	ASSERT(db->db_dirtycnt > 0);
 	db->db_dirtycnt -= 1;
 	db->db_data_pending = NULL;
-	dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg);
+	dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg, B_FALSE);
 }
 
 static void
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c
index 26471fda0..4e2a73383 100644
--- a/module/zfs/dnode.c
+++ b/module/zfs/dnode.c
@@ -1576,11 +1576,11 @@ void
 dnode_rele(dnode_t *dn, void *tag)
 {
 	mutex_enter(&dn->dn_mtx);
-	dnode_rele_and_unlock(dn, tag);
+	dnode_rele_and_unlock(dn, tag, B_FALSE);
 }
 
 void
-dnode_rele_and_unlock(dnode_t *dn, void *tag)
+dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting)
 {
 	uint64_t refs;
 	/* Get while the hold prevents the dnode from moving. */
@@ -1612,7 +1612,7 @@ dnode_rele_and_unlock(dnode_t *dn, void *tag)
 		 * asserted anyway when the handle gets destroyed.
 		 */
 		mutex_enter(&db->db_mtx);
-		dbuf_rele_and_unlock(db, dnh);
+		dbuf_rele_and_unlock(db, dnh, evicting);
 	}
 }
 
diff --git a/module/zfs/dnode_sync.c b/module/zfs/dnode_sync.c
index b1f734a82..f0459e47d 100644
--- a/module/zfs/dnode_sync.c
+++ b/module/zfs/dnode_sync.c
@@ -457,7 +457,7 @@ dnode_evict_dbufs(dnode_t *dn)
 			 * flow would look like:
 			 *
 			 * dbuf_destroy():
-			 *   dnode_rele_and_unlock(parent_dbuf):
+			 *   dnode_rele_and_unlock(parent_dbuf, evicting=TRUE):
 			 *	if (!cacheable || pending_evict)
 			 *	  dbuf_destroy()
 			 */
@@ -521,7 +521,7 @@ dnode_undirty_dbufs(list_t *list)
 			list_destroy(&dr->dt.di.dr_children);
 		}
 		kmem_free(dr, sizeof (dbuf_dirty_record_t));
-		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
+		dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg, B_FALSE);
 	}
 }