git: 6b69465efb48 - main - vfs_domount(): ensure that v_mountedhere and VIRF_MOUNTPOINT are set under the vnode lock

[Konstantin Belousov]

The branch main has been updated by kib:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=6b69465efb48029e617282dcea5aac3e51e5e3d4

commit 6b69465efb48029e617282dcea5aac3e51e5e3d4
Author:     Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2022-10-27 20:22:43 +0000
Commit:     Konstantin Belousov <k...@freebsd.org>
CommitDate: 2022-10-29 11:29:55 +0000

    vfs_domount(): ensure that v_mountedhere and VIRF_MOUNTPOINT are set under 
the vnode lock
    
    Fixes:  f7833196bd6ba9bfc060a41b353422b15d6aa95b
    Reported and tested by: pho
    Reviewed by:    jah, markj (previous version)
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D37198
---
 sys/kern/vfs_mount.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 31566f521d22..f49312ed4f57 100644
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -1201,10 +1201,16 @@ vfs_domount_first(
                mp->mnt_kern_flag &= ~MNTK_ASYNC;
        MNT_IUNLOCK(mp);
 
+       /*
+        * VIRF_MOUNTPOINT and v_mountedhere need to be set under the
+        * vp lock to satisfy vfs_lookup() requirements.
+        */
+       VOP_LOCK(vp, LK_EXCLUSIVE | LK_RETRY);
        VI_LOCK(vp);
        vn_irflag_set_locked(vp, VIRF_MOUNTPOINT);
        vp->v_mountedhere = mp;
        VI_UNLOCK(vp);
+       VOP_UNLOCK(vp);
        cache_purge(vp);
 
        /*