From 6300e65d2d5f4a0ed896a5f54c02ee60a90fb59f Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 18 May 2010 14:29:29 +0200 Subject: [PATCH 3/4] writeback: ensure that WB_SYNC_NONE writeback with sb pinned is sync Even if the writeout itself isn't a data integrity operation, we need to ensure that the caller doesn't drop the sb umount sem before we have actually done the writeback. This is a fixup for commit e913fc82. Signed-off-by: Jens Axboe (cherry picked from commit 7c8a3554c683f512dbcee26faedb42e4c05f12fa) --- fs/fs-writeback.c | 16 +++++++++++----- 1 files changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 03a2612..29b4dbe 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -193,7 +193,8 @@ static void bdi_wait_on_work_clear(struct bdi_work *work) } static void bdi_alloc_queue_work(struct backing_dev_info *bdi, - struct wb_writeback_args *args) + struct wb_writeback_args *args, + int wait) { struct bdi_work *work; @@ -205,6 +206,8 @@ static void bdi_alloc_queue_work(struct backing_dev_info *bdi, if (work) { bdi_work_init(work, args); bdi_queue_work(bdi, work); + if (wait) + bdi_wait_on_work_clear(work); } else { struct bdi_writeback *wb = &bdi->wb; @@ -278,7 +281,7 @@ void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, args.for_background = 1; } - bdi_alloc_queue_work(bdi, &args); + bdi_alloc_queue_work(bdi, &args, sb_locked); } /* @@ -911,6 +914,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) while ((work = get_next_work_item(bdi, wb)) != NULL) { struct wb_writeback_args args = work->args; + int post_clear; /* * Override sync mode, in case we must wait for completion @@ -918,11 +922,13 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) if (force_wait) work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; + post_clear = WB_SYNC_ALL || args.sb_pinned; + /* * If this isn't a data integrity operation, just notify * that we have seen this work and we are now starting it. */ - if (args.sync_mode == WB_SYNC_NONE) + if (!post_clear) wb_clear_pending(wb, work); wrote += wb_writeback(wb, &args); @@ -931,7 +937,7 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait) * This is a data integrity writeback, so only do the * notification when we have completed the work. */ - if (args.sync_mode == WB_SYNC_ALL) + if (post_clear) wb_clear_pending(wb, work); } @@ -998,7 +1004,7 @@ static void bdi_writeback_all(struct super_block *sb, long nr_pages) if (!bdi_has_dirty_io(bdi)) continue; - bdi_alloc_queue_work(bdi, &args); + bdi_alloc_queue_work(bdi, &args, 0); } rcu_read_unlock(); -- 1.7.0.4