// No space or similar, don't persist the listing.
		o.pool = 0
		o.Create = false
		o.ID = ""
		o.Transient = true
		return entries, errDiskFull
	}
	o.set = z.serverPools[o.pool].getHashedSetIndex(o.ID)
	saver := z.serverPools[o.pool].sets[o.set]

	// Disconnect from call above, but cancel on exit.
	listCtx, cancel := context.WithCancel(GlobalContext)
	saveCh := make(chan metaCacheEntry, metacacheBlockSize)

		var fw fileWriter
		switch maker := v.maker.(type) {
		case makeReg:
			fw = &regFileWriter{w, maker.size}
			wantStr = maker.wantStr
		case makeSparse:
			if !validateSparseEntries(maker.sph, maker.size) {
				t.Fatalf("invalid sparse map: %v", maker.sph)
			}
			spd := invertSparseEntries(maker.sph, maker.size)
			fw = &regFileWriter{w, maker.makeReg.size}
			fw = &sparseFileWriter{fw, spd, 0}

			cache.replace(b.Name, dataUsageRoot, *e)
			bucketCh <- b
		}
	}
	xioutil.SafeClose(bucketCh)

	bucketResults := make(chan dataUsageEntryInfo, len(disks))

	// Start async collector/saver.
	// This goroutine owns the cache.
	var saverWg sync.WaitGroup
	saverWg.Add(1)
	go func() {
		// Add jitter to the update time so multiple sets don't sync up.