Konstantin Belousov 5fc9e11c42 Save lower root vnode in nullfs mnt data instead of upper. ... Nullfs needs to know the root vnode of the lower fs during the operation. Currently it caches the upper vnode of it, which is also the root of the nullfs mount. On unmount, nullfs calls vflush() with rootrefs == 1, and aborts non-forced unmount if there are any more vnodes instantiated during vflush(). This means that the reference to the root vnode after failed non-forced unmount could be lost and nullm_rootvp points to the freed memory. Fix it by storing the reference for lower vnode instead, which is kept intact during vflush(). nullfs_root() now instantiates the upper vnode of lower root. Care about VV_ROOT flag in null_nodeget(). Reported and tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week		2020-01-28 11:29:06 +00:00
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null_subr.c	Save lower root vnode in nullfs mnt data instead of upper.	2020-01-28 11:29:06 +00:00
null_vfsops.c	Save lower root vnode in nullfs mnt data instead of upper.	2020-01-28 11:29:06 +00:00
null_vnops.c	vfs: drop the mostly unused flags argument from VOP_UNLOCK	2020-01-03 22:29:58 +00:00
null.h	Save lower root vnode in nullfs mnt data instead of upper.	2020-01-28 11:29:06 +00:00