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diff usr/src/uts/common/fs/zfs/dnode.c @ 4944:96d96f8de974

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6569719 panic dangling dbufs (dn=ffffffff28814d30, dbuf=ffffffff20756008) 6573361 panic turnstile_block, unowned mutex 6584864 $MOS is not properly bounded by pool size 6585265 need bonus resize interface 6587723 BAD TRAP: type=e (#pf Page fault) occurred in module "zfs" due to a NULL pointer dereference 6589799 dangling dbuf after zinject 6594025 panic: dangling dbufs during shutdown
author maybee
date Sun, 26 Aug 2007 11:19:04 -0700
parents ed36b0e652bc
children 20c04e18c58c
line wrap: on
line diff
--- a/usr/src/uts/common/fs/zfs/dnode.c	Fri Aug 24 17:45:12 2007 -0700
+++ b/usr/src/uts/common/fs/zfs/dnode.c	Sun Aug 26 11:19:04 2007 -0700
@@ -240,6 +240,23 @@
 	else return (0);
 }
 
+void
+dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx)
+{
+	ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
+
+	dnode_setdirty(dn, tx);
+	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
+	ASSERT3U(newsize, <=, DN_MAX_BONUSLEN -
+	    (dn->dn_nblkptr-1) * sizeof (blkptr_t));
+	dn->dn_bonuslen = newsize;
+	if (newsize == 0)
+		dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN;
+	else
+		dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
+	rw_exit(&dn->dn_struct_rwlock);
+}
+
 static void
 dnode_setdblksz(dnode_t *dn, int size)
 {
@@ -363,6 +380,7 @@
 	for (i = 0; i < TXG_SIZE; i++) {
 		ASSERT3U(dn->dn_next_nlevels[i], ==, 0);
 		ASSERT3U(dn->dn_next_indblkshift[i], ==, 0);
+		ASSERT3U(dn->dn_next_bonuslen[i], ==, 0);
 		ASSERT3U(dn->dn_next_blksz[i], ==, 0);
 		ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
 		ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
@@ -390,6 +408,7 @@
 
 	dnode_setdirty(dn, tx);
 	dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs;
+	dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
 	dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz;
 }
 
@@ -397,7 +416,7 @@
 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
 {
-	int i;
+	int i, old_nblkptr;
 	dmu_buf_impl_t *db = NULL;
 
 	ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
@@ -414,7 +433,7 @@
 		ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
 
 	/* clean up any unreferenced dbufs */
-	(void) dnode_evict_dbufs(dn, 0);
+	dnode_evict_dbufs(dn);
 	ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
 
 	/*
@@ -437,38 +456,18 @@
 	}
 	dnode_setdblksz(dn, blocksize);
 	dnode_setdirty(dn, tx);
+	dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
 	dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
 	rw_exit(&dn->dn_struct_rwlock);
-	if (db) {
+	if (db)
 		dbuf_rele(db, FTAG);
-		db = NULL;
-	}
 
 	/* change type */
 	dn->dn_type = ot;
 
-	if (dn->dn_bonuslen != bonuslen) {
-		/* change bonus size */
-		if (bonuslen == 0)
-			bonuslen = 1; /* XXX */
-		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
-		if (dn->dn_bonus == NULL)
-			dn->dn_bonus = dbuf_create_bonus(dn);
-		db = dn->dn_bonus;
-		rw_exit(&dn->dn_struct_rwlock);
-		if (refcount_add(&db->db_holds, FTAG) == 1)
-			dnode_add_ref(dn, db);
-		VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));
-		mutex_enter(&db->db_mtx);
-		ASSERT3U(db->db.db_size, ==, dn->dn_bonuslen);
-		ASSERT(db->db.db_data != NULL);
-		db->db.db_size = bonuslen;
-		mutex_exit(&db->db_mtx);
-		(void) dbuf_dirty(db, tx);
-	}
-
 	/* change bonus size and type */
 	mutex_enter(&dn->dn_mtx);
+	old_nblkptr = dn->dn_nblkptr;
 	dn->dn_bonustype = bonustype;
 	dn->dn_bonuslen = bonuslen;
 	dn->dn_nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
@@ -476,12 +475,15 @@
 	dn->dn_compress = ZIO_COMPRESS_INHERIT;
 	ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
 
-	/*
-	 * NB: we have to do the dbuf_rele after we've changed the
-	 * dn_bonuslen, for the sake of dbuf_verify().
-	 */
-	if (db)
-		dbuf_rele(db, FTAG);
+	/* XXX - for now, we can't make nblkptr smaller */
+	ASSERT3U(dn->dn_nblkptr, >=, old_nblkptr);
+
+	/* fix up the bonus db_size if dn_nblkptr has changed */
+	if (dn->dn_bonus && dn->dn_bonuslen != old_nblkptr) {
+		dn->dn_bonus->db.db_size =
+		    DN_MAX_BONUSLEN - (dn->dn_nblkptr-1) * sizeof (blkptr_t);
+		ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
+	}
 
 	dn->dn_allocated_txg = tx->tx_txg;
 	mutex_exit(&dn->dn_mtx);
@@ -646,11 +648,22 @@
 	return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, tag, dnp));
 }
 
-void
+/*
+ * Can only add a reference if there is already at least one
+ * reference on the dnode.  Returns FALSE if unable to add a
+ * new reference.
+ */
+boolean_t
 dnode_add_ref(dnode_t *dn, void *tag)
 {
-	ASSERT(refcount_count(&dn->dn_holds) > 0);
-	(void) refcount_add(&dn->dn_holds, tag);
+	mutex_enter(&dn->dn_mtx);
+	if (refcount_is_zero(&dn->dn_holds)) {
+		mutex_exit(&dn->dn_mtx);
+		return (FALSE);
+	}
+	VERIFY(1 < refcount_add(&dn->dn_holds, tag));
+	mutex_exit(&dn->dn_mtx);
+	return (TRUE);
 }
 
 void
@@ -658,7 +671,9 @@
 {
 	uint64_t refs;
 
+	mutex_enter(&dn->dn_mtx);
 	refs = refcount_remove(&dn->dn_holds, tag);
+	mutex_exit(&dn->dn_mtx);
 	/* NOTE: the DNODE_DNODE does not have a dn_dbuf */
 	if (refs == 0 && dn->dn_dbuf)
 		dbuf_rele(dn->dn_dbuf, dn);
@@ -694,6 +709,7 @@
 
 	ASSERT(!refcount_is_zero(&dn->dn_holds) || list_head(&dn->dn_dbufs));
 	ASSERT(dn->dn_datablksz != 0);
+	ASSERT3U(dn->dn_next_bonuslen[txg&TXG_MASK], ==, 0);
 	ASSERT3U(dn->dn_next_blksz[txg&TXG_MASK], ==, 0);
 
 	dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
@@ -716,7 +732,7 @@
 	 * dnode will hang around after we finish processing its
 	 * children.
 	 */
-	dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg);
+	VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg));
 
 	(void) dbuf_dirty(dn->dn_dbuf, tx);