From 86e115e21e5bdeee73c88c5a1a73a29d9637380a Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Tue, 12 Dec 2023 15:59:24 -0500
Subject: [PATCH] dbuf: Set dr_data when unoverriding after clone
Block cloning normally creates dirty record without dr_data. But if
the block is read after cloning, it is moved into DB_CACHED state and
receives the data buffer. If after that we call dbuf_unoverride()
to convert the dirty record into normal write, we should give it the
data buffer from dbuf and release one.
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes #15654
Closes #15656
---
module/zfs/dbuf.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index a07fe1733586..03c97941d6d3 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -1919,7 +1919,6 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
dmu_buf_impl_t *db = dr->dr_dbuf;
blkptr_t *bp = &dr->dt.dl.dr_overridden_by;
uint64_t txg = dr->dr_txg;
- boolean_t release;
ASSERT(MUTEX_HELD(&db->db_mtx));
/*
@@ -1940,7 +1939,10 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite)
zio_free(db->db_objset->os_spa, txg, bp);
- release = !dr->dt.dl.dr_brtwrite;
+ if (dr->dt.dl.dr_brtwrite) {
+ ASSERT0P(dr->dt.dl.dr_data);
+ dr->dt.dl.dr_data = db->db_buf;
+ }
dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
dr->dt.dl.dr_nopwrite = B_FALSE;
dr->dt.dl.dr_brtwrite = B_FALSE;
@@ -1954,7 +1956,7 @@ dbuf_unoverride(dbuf_dirty_record_t *dr)
* the buf thawed to save the effort of freezing &
* immediately re-thawing it.
*/
- if (release)
+ if (dr->dt.dl.dr_data)
arc_release(dr->dt.dl.dr_data, db);
}