code:bflush - ikarishinjieva/unixV6-code-analyze-chs GitHub Wiki

5223

5224 /* make sure all write-behind blocks

5225 * on dev (or NODEV for all)

5226 * are flushed out.

5227 * (from umount and update)

5228 */

5229 bflush(dev)

5230 {

5231 register struct buf *bp;

5232

5233 loop:

5234 spl6();

关中断

5235 for (bp = bfreelist.av_forw; bp != &bfreelist;

5236 bp = bp->av_forw) {

5237 if (bp->b_flags&B_DELWRI &&

5238 (dev == NODEV||dev == bp->b_dev)) {

遍历自由队列,寻找带有延迟写标识,且其对应设备号为NODEV或是dev(函数传入参数)的缓存块

5239 bp->b_flags =| B_ASYNC;

5240 notavil(bp);

5241 bwrite(bp);

对于找到的缓存块,置异步写标识

将其从自由队列中取出

然后写回相应设备

5242 goto loop;

5243 }

5244 }

5245 spl0();

开中断

5246 }

5247 /* ------------------------- */