The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=4559700a0a99376640a8913d08bdf0cfb0124d4a
commit 4559700a0a99376640a8913d08bdf0cfb0124d4a Author: Konstantin Belousov <[email protected]> AuthorDate: 2022-01-23 00:33:18 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2022-01-31 02:46:21 +0000 ffs_snapblkfree(): add a comment explaining lockmgr invocation Reviewed by: markj, mckusick Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D34072 --- sys/ufs/ffs/ffs_snapshot.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/sys/ufs/ffs/ffs_snapshot.c b/sys/ufs/ffs/ffs_snapshot.c index 1257ee8f8f4f..6cda327c8fcd 100644 --- a/sys/ufs/ffs/ffs_snapshot.c +++ b/sys/ufs/ffs/ffs_snapshot.c @@ -1800,9 +1800,15 @@ retry: VI_UNLOCK(devvp); return (0); } + + /* + * Use LK_SLEEPFAIL because sn might be freed under us while + * both devvp interlock and snaplk are not owned. + */ if (lockmgr(&sn->sn_lock, LK_INTERLOCK | LK_EXCLUSIVE | LK_SLEEPFAIL, VI_MTX(devvp)) != 0) goto retry; + TAILQ_FOREACH(ip, &sn->sn_head, i_nextsnap) { vp = ITOV(ip); if (DOINGSOFTDEP(vp))
