[PATCH] md: enable the bitmap write-back daemon and wait for it.
Currently we don't wait for updates to the bitmap to be flushed to disk properly. The infrastructure all there, but it isn't being used.... A separate kernel thread (bitmap_writeback_daemon) is needed to wait for each page as we cannot get callbacks when a page write completes. Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
NeilBrown
Linus Torvalds
Родитель
bfb39fba4e
Коммит
77ad4bc706
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@ -261,30 +261,33 @@ char *file_path(struct file *file, char *buf, int count)
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/*
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* write out a page
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*/
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static int write_page(struct page *page, int wait)
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static int write_page(struct bitmap *bitmap, struct page *page, int wait)
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{
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int ret = -ENOMEM;
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lock_page(page);
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if (page->mapping == NULL)
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goto unlock_out;
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else if (i_size_read(page->mapping->host) < page->index << PAGE_SHIFT) {
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ret = -ENOENT;
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goto unlock_out;
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}
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ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
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if (!ret)
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ret = page->mapping->a_ops->commit_write(NULL, page, 0,
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PAGE_SIZE);
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if (ret) {
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unlock_out:
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unlock_page(page);
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return ret;
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}
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set_page_dirty(page); /* force it to be written out */
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if (!wait) {
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/* add to list to be waited for by daemon */
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struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
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item->page = page;
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page_cache_get(page);
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spin_lock(&bitmap->write_lock);
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list_add(&item->list, &bitmap->complete_pages);
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spin_unlock(&bitmap->write_lock);
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md_wakeup_thread(bitmap->writeback_daemon);
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}
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return write_one_page(page, wait);
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}
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@ -343,14 +346,13 @@ int bitmap_update_sb(struct bitmap *bitmap)
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spin_unlock_irqrestore(&bitmap->lock, flags);
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return 0;
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}
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page_cache_get(bitmap->sb_page);
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spin_unlock_irqrestore(&bitmap->lock, flags);
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sb = (bitmap_super_t *)kmap(bitmap->sb_page);
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sb->events = cpu_to_le64(bitmap->mddev->events);
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if (!bitmap->mddev->degraded)
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sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
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kunmap(bitmap->sb_page);
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return write_page(bitmap->sb_page, 0);
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return write_page(bitmap, bitmap->sb_page, 0);
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}
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/* print out the bitmap file superblock */
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@ -556,10 +558,10 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
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static void bitmap_stop_daemons(struct bitmap *bitmap);
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/* dequeue the next item in a page list -- don't call from irq context */
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static struct page_list *dequeue_page(struct bitmap *bitmap,
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struct list_head *head)
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static struct page_list *dequeue_page(struct bitmap *bitmap)
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{
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struct page_list *item = NULL;
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struct list_head *head = &bitmap->complete_pages;
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spin_lock(&bitmap->write_lock);
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if (list_empty(head))
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@ -573,23 +575,15 @@ out:
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static void drain_write_queues(struct bitmap *bitmap)
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{
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struct list_head *queues[] = { &bitmap->complete_pages, NULL };
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struct list_head *head;
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struct page_list *item;
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int i;
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for (i = 0; queues[i]; i++) {
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head = queues[i];
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while ((item = dequeue_page(bitmap, head))) {
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page_cache_release(item->page);
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mempool_free(item, bitmap->write_pool);
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}
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while ((item = dequeue_page(bitmap))) {
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/* don't bother to wait */
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page_cache_release(item->page);
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mempool_free(item, bitmap->write_pool);
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}
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spin_lock(&bitmap->write_lock);
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bitmap->writes_pending = 0; /* make sure waiters continue */
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wake_up(&bitmap->write_wait);
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spin_unlock(&bitmap->write_lock);
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}
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static void bitmap_file_put(struct bitmap *bitmap)
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@ -734,13 +728,13 @@ int bitmap_unplug(struct bitmap *bitmap)
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spin_unlock_irqrestore(&bitmap->lock, flags);
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if (attr & (BITMAP_PAGE_DIRTY | BITMAP_PAGE_NEEDWRITE))
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if (write_page(page, 0))
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if (write_page(bitmap, page, 0))
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return 1;
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}
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if (wait) { /* if any writes were performed, we need to wait on them */
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spin_lock_irq(&bitmap->write_lock);
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wait_event_lock_irq(bitmap->write_wait,
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bitmap->writes_pending == 0, bitmap->write_lock,
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list_empty(&bitmap->complete_pages), bitmap->write_lock,
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wake_up_process(bitmap->writeback_daemon->tsk));
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spin_unlock_irq(&bitmap->write_lock);
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}
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@ -841,7 +835,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
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*/
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memset(page_address(page) + offset, 0xff,
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PAGE_SIZE - offset);
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ret = write_page(page, 1);
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ret = write_page(bitmap, page, 1);
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if (ret) {
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kunmap(page);
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/* release, page not in filemap yet */
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@ -934,7 +928,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
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}
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spin_unlock_irqrestore(&bitmap->lock, flags);
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if (attr & BITMAP_PAGE_NEEDWRITE) {
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if (write_page(page, 0))
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if (write_page(bitmap, page, 0))
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bitmap_file_kick(bitmap);
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page_cache_release(page);
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}
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@ -950,7 +944,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
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if (get_page_attr(bitmap, lastpage) & BITMAP_PAGE_NEEDWRITE) {
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clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
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spin_unlock_irqrestore(&bitmap->lock, flags);
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err = write_page(lastpage, 0);
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err = write_page(bitmap, lastpage, 0);
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} else {
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set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
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spin_unlock_irqrestore(&bitmap->lock, flags);
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@ -998,7 +992,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
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if (get_page_attr(bitmap, lastpage) &BITMAP_PAGE_NEEDWRITE) {
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clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
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spin_unlock_irqrestore(&bitmap->lock, flags);
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err = write_page(lastpage, 0);
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err = write_page(bitmap, lastpage, 0);
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} else {
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set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
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spin_unlock_irqrestore(&bitmap->lock, flags);
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@ -1034,46 +1028,40 @@ static void bitmap_writeback_daemon(mddev_t *mddev)
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struct page_list *item;
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int err = 0;
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while (1) {
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PRINTK("%s: bitmap writeback daemon waiting...\n", bmname(bitmap));
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down_interruptible(&bitmap->write_done);
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if (signal_pending(current)) {
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printk(KERN_INFO
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"%s: bitmap writeback daemon got signal, exiting...\n",
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bmname(bitmap));
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break;
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}
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if (signal_pending(current)) {
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printk(KERN_INFO
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"%s: bitmap writeback daemon got signal, exiting...\n",
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bmname(bitmap));
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err = -EINTR;
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goto out;
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}
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PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
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/* wait on bitmap page writebacks */
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while ((item = dequeue_page(bitmap, &bitmap->complete_pages))) {
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page = item->page;
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mempool_free(item, bitmap->write_pool);
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PRINTK("wait on page writeback: %p %lu\n", page, bitmap->writes_pending);
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wait_on_page_writeback(page);
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PRINTK("finished page writeback: %p %lu\n", page, bitmap->writes_pending);
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spin_lock(&bitmap->write_lock);
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if (!--bitmap->writes_pending)
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wake_up(&bitmap->write_wait);
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spin_unlock(&bitmap->write_lock);
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err = PageError(page);
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page_cache_release(page);
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if (err) {
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printk(KERN_WARNING "%s: bitmap file writeback "
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"failed (page %lu): %d\n",
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bmname(bitmap), page->index, err);
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bitmap_file_kick(bitmap);
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goto out;
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}
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PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
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/* wait on bitmap page writebacks */
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while ((item = dequeue_page(bitmap))) {
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page = item->page;
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mempool_free(item, bitmap->write_pool);
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PRINTK("wait on page writeback: %p\n", page);
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wait_on_page_writeback(page);
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PRINTK("finished page writeback: %p\n", page);
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err = PageError(page);
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page_cache_release(page);
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if (err) {
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printk(KERN_WARNING "%s: bitmap file writeback "
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"failed (page %lu): %d\n",
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bmname(bitmap), page->index, err);
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bitmap_file_kick(bitmap);
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goto out;
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}
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}
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out:
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out:
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wake_up(&bitmap->write_wait);
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if (err) {
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printk(KERN_INFO "%s: bitmap writeback daemon exiting (%d)\n",
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bmname(bitmap), err);
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bmname(bitmap), err);
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daemon_exit(bitmap, &bitmap->writeback_daemon);
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}
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return;
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}
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static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
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@ -1375,7 +1363,7 @@ int bitmap_setallbits(struct bitmap *bitmap)
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spin_unlock_irqrestore(&bitmap->lock, flags);
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memset(kmap(page), 0xff, PAGE_SIZE);
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kunmap(page);
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if (write_page(page, 0))
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if (write_page(bitmap, page, 0))
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return 1;
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}
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@ -1443,7 +1431,6 @@ int bitmap_create(mddev_t *mddev)
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mddev->bitmap = bitmap;
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spin_lock_init(&bitmap->write_lock);
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init_MUTEX_LOCKED(&bitmap->write_done);
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INIT_LIST_HEAD(&bitmap->complete_pages);
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init_waitqueue_head(&bitmap->write_wait);
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bitmap->write_pool = mempool_create(WRITE_POOL_SIZE, write_pool_alloc,
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@ -233,21 +233,12 @@ struct bitmap {
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unsigned long daemon_sleep; /* how many seconds between updates? */
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/*
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* bitmap write daemon - this daemon performs writes to the bitmap file
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* this thread is only needed because of a limitation in ext3 (jbd)
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* that does not allow a task to have two journal transactions ongoing
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* simultaneously (even if the transactions are for two different
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* filesystems) -- in the case of bitmap, that would be the filesystem
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* that the bitmap file resides on and the filesystem that is mounted
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* on the md device -- see current->journal_info in jbd/transaction.c
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* bitmap_writeback_daemon waits for file-pages that have been written,
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* as there is no way to get a call-back when a page write completes.
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*/
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mdk_thread_t *writeback_daemon;
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spinlock_t write_lock;
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struct semaphore write_ready;
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struct semaphore write_done;
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unsigned long writes_pending;
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wait_queue_head_t write_wait;
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struct list_head write_pages;
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struct list_head complete_pages;
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mempool_t *write_pool;
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};
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