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that use it. Specifically, vop_stdlock uses the lock pointed to by vp->v_vnlock. By default, getnewvnode sets up vp->v_vnlock to reference vp->v_lock. Filesystems that wish to use the default do not need to allocate a lock at the front of their node structure (as some still did) or do a lockinit. They can simply start using vn_lock/VOP_UNLOCK. Filesystems that wish to manage their own locks, but still use the vop_stdlock functions (such as nullfs) can simply replace vp->v_vnlock with a pointer to the lock that they wish to have used for the vnode. Such filesystems are responsible for setting the vp->v_vnlock back to the default in their vop_reclaim routine (e.g., vp->v_vnlock = &vp->v_lock). In theory, this set of changes cleans up the existing filesystem lock interface and should have no function change to the existing locking scheme. Sponsored by: DARPA & NAI Labs. |
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| .. | ||
| null_subr.c | ||
| null_vfsops.c | ||
| null_vnops.c | ||
| null.h | ||