Fix two abd_gang_add_gang() issues.

- There is no reason to assert that added gang is not empty.  It
may be weird to add an empty gang, but it is legal.
 - When moving chain list from the added gang clear its size, or it
will trigger assertion in abd_verify() when that gang is freed.

Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #14816
This commit is contained in:
Alexander Motin 2023-05-05 12:17:55 -04:00 committed by GitHub
parent 6fa6bb051c
commit 190290a9ac
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@ -370,7 +370,20 @@ abd_gang_add_gang(abd_t *pabd, abd_t *cabd, boolean_t free_on_free)
* will retain all the free_on_free settings after being
* added to the parents list.
*/
#ifdef ZFS_DEBUG
/*
* If cabd had abd_parent, we have to drop it here. We can't
* transfer it to pabd, nor we can clear abd_size leaving it.
*/
if (cabd->abd_parent != NULL) {
(void) zfs_refcount_remove_many(
&cabd->abd_parent->abd_children,
cabd->abd_size, cabd);
cabd->abd_parent = NULL;
}
#endif
pabd->abd_size += cabd->abd_size;
cabd->abd_size = 0;
list_move_tail(&ABD_GANG(pabd).abd_gang_chain,
&ABD_GANG(cabd).abd_gang_chain);
ASSERT(list_is_empty(&ABD_GANG(cabd).abd_gang_chain));
@ -408,7 +421,6 @@ abd_gang_add(abd_t *pabd, abd_t *cabd, boolean_t free_on_free)
*/
if (abd_is_gang(cabd)) {
ASSERT(!list_link_active(&cabd->abd_gang_link));
ASSERT(!list_is_empty(&ABD_GANG(cabd).abd_gang_chain));
return (abd_gang_add_gang(pabd, cabd, free_on_free));
}
ASSERT(!abd_is_gang(cabd));