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Date:      Thu, 15 Apr 2021 12:48:41 GMT
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Subject:   git: e3d675958539 - main - b_vflags update requries bufobj lock
Message-ID:  <202104151248.13FCmfbh007766@gitrepo.freebsd.org>

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The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=e3d675958539eee899d42438f5b46a26f3c64902

commit e3d675958539eee899d42438f5b46a26f3c64902
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2021-04-13 10:22:56 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2021-04-15 12:47:42 +0000

    b_vflags update requries bufobj lock
    
    The trunc_dependencies() issue was reported by  Alexander Lochmann
    <alexander.lochmann@tu-dortmund.de>, who found the problem by performing
    lock analysis using LockDoc, see https://doi.org/10.1145/3302424.3303948.
    
    Tested by:      pho
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
---
 sys/ufs/ffs/ffs_softdep.c | 2 ++
 sys/ufs/ffs/ffs_vnops.c   | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c
index 0091b5dcd3b8..23c0cf6e128b 100644
--- a/sys/ufs/ffs/ffs_softdep.c
+++ b/sys/ufs/ffs/ffs_softdep.c
@@ -7546,7 +7546,9 @@ cleanrestart:
 			BO_LOCK(bo);
 			goto cleanrestart;
 		}
+		BO_LOCK(bo);
 		bp->b_vflags |= BV_SCANNED;
+		BO_UNLOCK(bo);
 		bremfree(bp);
 		if (blkoff != 0) {
 			allocbuf(bp, blkoff);
diff --git a/sys/ufs/ffs/ffs_vnops.c b/sys/ufs/ffs/ffs_vnops.c
index dc638595eb7b..05eb19c0ee13 100644
--- a/sys/ufs/ffs/ffs_vnops.c
+++ b/sys/ufs/ffs/ffs_vnops.c
@@ -321,8 +321,9 @@ loop:
 			if (BUF_LOCK(bp,
 			    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
 			    BO_LOCKPTR(bo)) != 0) {
+				BO_LOCK(bo);
 				bp->b_vflags &= ~BV_SCANNED;
-				goto next;
+				goto next_locked;
 			}
 		} else
 			continue;
@@ -385,6 +386,7 @@ next:
 		 * to start from a known point.
 		 */
 		BO_LOCK(bo);
+next_locked:
 		nbp = TAILQ_FIRST(&bo->bo_dirty.bv_hd);
 	}
 	if (waitfor != MNT_WAIT) {



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