illumos gate

The vnode's v_path is stable only in a case the v_lock is held. The nice example of that is in the vn_copypath() function implementation. Unfortunately, some v_path readers does not hold the v_lock when they work with v_path, so they are in danger that the v_path might get freed and/or replaced under their hands.

Examples¶

From nfs4_srv_ns.c

181    vpathlen = vp->v_path ? strlen(vp->v_path) : 0;
182    kex->ex_pathlen = vpathlen + strlen(PSEUDOFS_SUFFIX);
183    kex->ex_path = kmem_alloc(kex->ex_pathlen + 1, KM_SLEEP);
184
185    if (vpathlen)
186        (void) strcpy(kex->ex_path, vp->v_path);

From tmp_vnops.c:

236
237                    zcmn_err(GLOBAL_ZONEID,
238                        CE_WARN, "%s: File system full, " 
239                        "swap space limit exceeded",
240                        vfs->vfs_vnodecovered->v_path);