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-rw-r--r--module/zfs/dbuf.c85
1 files changed, 34 insertions, 51 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index faa6cc345..d655d6621 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -64,7 +64,7 @@ static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data *dh,
static int __dbuf_hold_impl(struct dbuf_hold_impl_data *dh);
static void dbuf_destroy(dmu_buf_impl_t *db);
-static int dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
+static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
/*
@@ -546,7 +546,7 @@ dbuf_read_done(zio_t *zio, arc_buf_t *buf, void *vdb)
} else {
ASSERT(db->db_blkid != DMU_BONUS_BLKID);
ASSERT3P(db->db_buf, ==, NULL);
- VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(buf, db));
db->db_state = DB_UNCACHED;
}
cv_broadcast(&db->db_changed);
@@ -875,10 +875,12 @@ dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
continue;
/* found a level 0 buffer in the range */
- if (dbuf_undirty(db, tx))
+ mutex_enter(&db->db_mtx);
+ if (dbuf_undirty(db, tx)) {
+ /* mutex has been dropped and dbuf destroyed */
continue;
+ }
- mutex_enter(&db->db_mtx);
if (db->db_state == DB_UNCACHED ||
db->db_state == DB_NOFILL ||
db->db_state == DB_EVICTING) {
@@ -1005,7 +1007,7 @@ dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
mutex_enter(&db->db_mtx);
dbuf_set_data(db, buf);
- VERIFY(arc_buf_remove_ref(obuf, db) == 1);
+ VERIFY(arc_buf_remove_ref(obuf, db));
db->db.db_size = size;
if (db->db_level == 0) {
@@ -1306,7 +1308,10 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
return (dr);
}
-static int
+/*
+ * Return TRUE if this evicted the dbuf.
+ */
+static boolean_t
dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
{
dnode_t *dn;
@@ -1315,18 +1320,17 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
ASSERT(txg != 0);
ASSERT(db->db_blkid != DMU_BONUS_BLKID);
+ ASSERT0(db->db_level);
+ ASSERT(MUTEX_HELD(&db->db_mtx));
- mutex_enter(&db->db_mtx);
/*
* If this buffer is not dirty, we're done.
*/
for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
if (dr->dr_txg <= txg)
break;
- if (dr == NULL || dr->dr_txg < txg) {
- mutex_exit(&db->db_mtx);
- return (0);
- }
+ if (dr == NULL || dr->dr_txg < txg)
+ return (B_FALSE);
ASSERT(dr->dr_txg == txg);
ASSERT(dr->dr_dbuf == db);
@@ -1334,24 +1338,12 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
dn = DB_DNODE(db);
/*
- * If this buffer is currently held, we cannot undirty
- * it, since one of the current holders may be in the
- * middle of an update. Note that users of dbuf_undirty()
- * should not place a hold on the dbuf before the call.
- * Also note: we can get here with a spill block, so
- * test for that similar to how dbuf_dirty does.
+ * Note: This code will probably work even if there are concurrent
+ * holders, but it is untested in that scenerio, as the ZPL and
+ * ztest have additional locking (the range locks) that prevents
+ * that type of concurrent access.
*/
- if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
- mutex_exit(&db->db_mtx);
- /* Make sure we don't toss this buffer at sync phase */
- if (db->db_blkid != DMU_SPILL_BLKID) {
- mutex_enter(&dn->dn_mtx);
- dnode_clear_range(dn, db->db_blkid, 1, tx);
- mutex_exit(&dn->dn_mtx);
- }
- DB_DNODE_EXIT(db);
- return (0);
- }
+ ASSERT3U(refcount_count(&db->db_holds), ==, db->db_dirtycnt);
dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
@@ -1380,21 +1372,13 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
}
DB_DNODE_EXIT(db);
- if (db->db_level == 0) {
- if (db->db_state != DB_NOFILL) {
- dbuf_unoverride(dr);
+ if (db->db_state != DB_NOFILL) {
+ dbuf_unoverride(dr);
- ASSERT(db->db_buf != NULL);
- ASSERT(dr->dt.dl.dr_data != NULL);
- if (dr->dt.dl.dr_data != db->db_buf)
- VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
- db) == 1);
- }
- } else {
ASSERT(db->db_buf != NULL);
- ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
- mutex_destroy(&dr->dt.di.dr_mtx);
- list_destroy(&dr->dt.di.dr_children);
+ ASSERT(dr->dt.dl.dr_data != NULL);
+ if (dr->dt.dl.dr_data != db->db_buf)
+ VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data, db));
}
kmem_free(dr, sizeof (dbuf_dirty_record_t));
@@ -1406,13 +1390,12 @@ dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
dbuf_set_data(db, NULL);
- VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(buf, db));
dbuf_evict(db);
- return (1);
+ return (B_TRUE);
}
- mutex_exit(&db->db_mtx);
- return (0);
+ return (B_FALSE);
}
#pragma weak dmu_buf_will_dirty = dbuf_will_dirty
@@ -1511,7 +1494,7 @@ dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
mutex_exit(&db->db_mtx);
(void) dbuf_dirty(db, tx);
bcopy(buf->b_data, db->db.db_data, db->db.db_size);
- VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(buf, db));
xuio_stat_wbuf_copied();
return;
}
@@ -1529,10 +1512,10 @@ dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
arc_release(db->db_buf, db);
}
dr->dt.dl.dr_data = buf;
- VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(db->db_buf, db));
} else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
arc_release(db->db_buf, db);
- VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(db->db_buf, db));
}
db->db_buf = NULL;
}
@@ -2168,10 +2151,10 @@ dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
* This dbuf has anonymous data associated with it.
*/
dbuf_set_data(db, NULL);
- VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ VERIFY(arc_buf_remove_ref(buf, db));
dbuf_evict(db);
} else {
- VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
+ VERIFY(!arc_buf_remove_ref(db->db_buf, db));
/*
* A dbuf will be eligible for eviction if either the
@@ -2669,7 +2652,7 @@ dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
if (db->db_state != DB_NOFILL) {
if (dr->dt.dl.dr_data != db->db_buf)
VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
- db) == 1);
+ db));
else if (!arc_released(db->db_buf))
arc_set_callback(db->db_buf, dbuf_do_evict, db);
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 14:56:01 +0000