Date: Tue, 11 Apr 2023 13:20:54 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: afa8f8971b86 - main - vn_start_write(): consistently set *mpp to NULL on error or after failed sleep Message-ID: <202304111320.33BDKsuv010229@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=afa8f8971b869b8b5d1468e431d18c615a35a63e commit afa8f8971b869b8b5d1468e431d18c615a35a63e Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2023-04-05 21:00:04 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2023-04-11 12:59:46 +0000 vn_start_write(): consistently set *mpp to NULL on error or after failed sleep This ensures that *mpp != NULL iff vn_finished_write() should be called, regardless of the returned error, except for V_NOWAIT. The only exception that must be maintained is the case where vn_start_write(V_NOWAIT) is called with the intent of later dropping other locks and then doing vn_start_write(V_XSLEEP), which needs the mp value calculated from the non-waitable call above it. Also note that V_XSLEEP is not supported by vn_start_secondary_write(). Reviewed by: markj, mjg (previous version), rmacklem (previous version) Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D39441 --- sys/kern/vfs_vnops.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index 122e53c0d9fb..52242cce0692 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -1935,7 +1935,10 @@ vn_start_write(struct vnode *vp, struct mount **mpp, int flags) if (vp == NULL) vfs_ref(mp); - return (vn_start_write_refed(mp, flags, false)); + error = vn_start_write_refed(mp, flags, false); + if (error != 0 && (flags & V_NOWAIT) == 0) + *mpp = NULL; + return (error); } /* @@ -1951,7 +1954,7 @@ vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) struct mount *mp; int error, mflags; - KASSERT((flags & ~V_VALID_FLAGS) == 0, + KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0, ("%s: invalid flags passed %d\n", __func__, flags)); retry: @@ -1989,6 +1992,7 @@ vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) if ((flags & V_NOWAIT) != 0) { MNT_REL(mp); MNT_IUNLOCK(mp); + *mpp = NULL; return (EWOULDBLOCK); } /* @@ -2004,6 +2008,7 @@ vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) vfs_rel(mp); if (error == 0) goto retry; + *mpp = NULL; return (error); }
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