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authorTejun Heo <tj@kernel.org>2015-08-25 20:11:52 +0200
committerJens Axboe <axboe@fb.com>2015-08-25 22:35:09 +0200
commit006a0973ed020a81fe1f24b511ce9feb53f70e44 (patch)
tree6a5ab2d9913302a2bcd5c725ed91682050c289d2 /fs/fs-writeback.c
parentLinux 4.2-rc8 (diff)
downloadlinux-006a0973ed020a81fe1f24b511ce9feb53f70e44.tar.xz
linux-006a0973ed020a81fe1f24b511ce9feb53f70e44.zip
writeback: sync_inodes_sb() must write out I_DIRTY_TIME inodes and always call wait_sb_inodes()
e79729123f63 ("writeback: don't issue wb_writeback_work if clean") updated writeback path to avoid kicking writeback work items if there are no inodes to be written out; unfortunately, the avoidance logic was too aggressive and broke sync_inodes_sb(). * sync_inodes_sb() must write out I_DIRTY_TIME inodes but I_DIRTY_TIME inodes dont't contribute to bdi/wb_has_dirty_io() tests and were being skipped over. * inodes are taken off wb->b_dirty/io/more_io lists after writeback starts on them. sync_inodes_sb() skipping wait_sb_inodes() when bdi_has_dirty_io() breaks it by making it return while writebacks are in-flight. This patch fixes the breakages by * Removing bdi_has_dirty_io() shortcut from bdi_split_work_to_wbs(). The callers are already testing the condition. * Removing bdi_has_dirty_io() shortcut from sync_inodes_sb() so that it always calls into bdi_split_work_to_wbs() and wait_sb_inodes(). * Making bdi_split_work_to_wbs() consider the b_dirty_time list for WB_SYNC_ALL writebacks. Kudos to Eryu, Dave and Jan for tracking down the issue. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e79729123f63 ("writeback: don't issue wb_writeback_work if clean") Link: http://lkml.kernel.org/g/20150812101204.GE17933@dhcp-13-216.nay.redhat.com Reported-and-bisected-by: Eryu Guan <eguan@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.com> Cc: Ted Ts'o <tytso@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 518c6294bf6c..5fa588e933d5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -844,14 +844,15 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
struct wb_iter iter;
might_sleep();
-
- if (!bdi_has_dirty_io(bdi))
- return;
restart:
rcu_read_lock();
bdi_for_each_wb(wb, bdi, &iter, next_blkcg_id) {
- if (!wb_has_dirty_io(wb) ||
- (skip_if_busy && writeback_in_progress(wb)))
+ /* SYNC_ALL writes out I_DIRTY_TIME too */
+ if (!wb_has_dirty_io(wb) &&
+ (base_work->sync_mode == WB_SYNC_NONE ||
+ list_empty(&wb->b_dirty_time)))
+ continue;
+ if (skip_if_busy && writeback_in_progress(wb))
continue;
base_work->nr_pages = wb_split_bdi_pages(wb, nr_pages);
@@ -899,8 +900,7 @@ static void bdi_split_work_to_wbs(struct backing_dev_info *bdi,
{
might_sleep();
- if (bdi_has_dirty_io(bdi) &&
- (!skip_if_busy || !writeback_in_progress(&bdi->wb))) {
+ if (!skip_if_busy || !writeback_in_progress(&bdi->wb)) {
base_work->auto_free = 0;
base_work->single_wait = 0;
base_work->single_done = 0;
@@ -2275,8 +2275,12 @@ void sync_inodes_sb(struct super_block *sb)
};
struct backing_dev_info *bdi = sb->s_bdi;
- /* Nothing to do? */
- if (!bdi_has_dirty_io(bdi) || bdi == &noop_backing_dev_info)
+ /*
+ * Can't skip on !bdi_has_dirty() because we should wait for !dirty
+ * inodes under writeback and I_DIRTY_TIME inodes ignored by
+ * bdi_has_dirty() need to be written out too.
+ */
+ if (bdi == &noop_backing_dev_info)
return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));