From f11fcae8401a3175f528e2f7917362645d570111 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 15 Sep 2009 09:53:35 +0200 Subject: [PATCH] writeback: only use bdi_writeback_all() for WB_SYNC_NONE writeout Data integrity writeback must use bdi_start_writeback() and ensure that wbc->sb and wbc->bdi are set. Acked-by: Jan Kara Signed-off-by: Jens Axboe --- fs/fs-writeback.c | 70 ++++++++++------------------------------------- 1 file changed, 14 insertions(+), 56 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index c5e91225501..14f06b45919 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -50,7 +50,6 @@ struct wb_writeback_args { */ struct bdi_work { struct list_head list; - struct list_head wait_list; struct rcu_head rcu_head; unsigned long seen; @@ -198,7 +197,8 @@ static void bdi_wait_on_work_clear(struct bdi_work *work) TASK_UNINTERRUPTIBLE); } -static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc) +static void bdi_alloc_queue_work(struct backing_dev_info *bdi, + struct writeback_control *wbc) { struct bdi_work *work; @@ -206,7 +206,7 @@ static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc) if (work) bdi_work_init(work, wbc); - return work; + bdi_queue_work(bdi, work); } void bdi_start_writeback(struct writeback_control *wbc) @@ -216,11 +216,9 @@ void bdi_start_writeback(struct writeback_control *wbc) * bdi_queue_work() will wake up the thread and flush old data. This * should ensure some amount of progress in freeing memory. */ - if (wbc->sync_mode != WB_SYNC_ALL) { - struct bdi_work *w = bdi_alloc_work(wbc); - - bdi_queue_work(wbc->bdi, w); - } else { + if (wbc->sync_mode != WB_SYNC_ALL) + bdi_alloc_queue_work(wbc->bdi, wbc); + else { struct bdi_work work; bdi_work_init(&work, wbc); @@ -860,67 +858,26 @@ int bdi_writeback_task(struct bdi_writeback *wb) } /* - * Schedule writeback for all backing devices. Expensive! If this is a data - * integrity operation, writeback will be complete when this returns. If - * we are simply called for WB_SYNC_NONE, then writeback will merely be - * scheduled to run. + * Schedule writeback for all backing devices. Can only be used for + * WB_SYNC_NONE writeback, WB_SYNC_ALL should use bdi_start_writeback() + * and pass in the superblock. */ static void bdi_writeback_all(struct writeback_control *wbc) { - const bool must_wait = wbc->sync_mode == WB_SYNC_ALL; struct backing_dev_info *bdi; - struct bdi_work *work; - LIST_HEAD(list); -restart: + WARN_ON(wbc->sync_mode == WB_SYNC_ALL); + spin_lock(&bdi_lock); list_for_each_entry(bdi, &bdi_list, bdi_list) { - struct bdi_work *work; - if (!bdi_has_dirty_io(bdi)) continue; - /* - * If work allocation fails, do the writes inline. We drop - * the lock and restart the list writeout. This should be OK, - * since this happens rarely and because the writeout should - * eventually make more free memory available. - */ - work = bdi_alloc_work(wbc); - if (!work) { - struct writeback_control __wbc; - - /* - * Not a data integrity writeout, just continue - */ - if (!must_wait) - continue; - - spin_unlock(&bdi_lock); - __wbc = *wbc; - __wbc.bdi = bdi; - writeback_inodes_wbc(&__wbc); - goto restart; - } - if (must_wait) - list_add_tail(&work->wait_list, &list); - - bdi_queue_work(bdi, work); + bdi_alloc_queue_work(bdi, wbc); } spin_unlock(&bdi_lock); - - /* - * If this is for WB_SYNC_ALL, wait for pending work to complete - * before returning. - */ - while (!list_empty(&list)) { - work = list_entry(list.next, struct bdi_work, wait_list); - list_del(&work->wait_list); - bdi_wait_on_work_clear(work); - call_rcu(&work->rcu_head, bdi_work_free); - } } /* @@ -1177,6 +1134,7 @@ long sync_inodes_sb(struct super_block *sb) { struct writeback_control wbc = { .sb = sb, + .bdi = sb->s_bdi, .sync_mode = WB_SYNC_ALL, .range_start = 0, .range_end = LLONG_MAX, @@ -1184,7 +1142,7 @@ long sync_inodes_sb(struct super_block *sb) long nr_to_write = LONG_MAX; /* doesn't actually matter */ wbc.nr_to_write = nr_to_write; - bdi_writeback_all(&wbc); + bdi_start_writeback(&wbc); wait_sb_inodes(&wbc); return nr_to_write - wbc.nr_to_write; }