writeback: queue work on stack in writeback_inodes_sb
If we want to rely on s_umount in the caller we need to wait for completion
of the I/O submission before returning to the caller. Refactor
bdi_sync_writeback into a bdi_queue_work_onstack helper and use it for this
case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index dbf6f10..7596669 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -178,30 +178,22 @@
}
/**
- * bdi_sync_writeback - start and wait for writeback
- * @bdi: the backing device to write from
+ * bdi_queue_work_onstack - start and wait for writeback
* @sb: write inodes from this super_block
*
* Description:
- * This does WB_SYNC_ALL data integrity writeback and waits for the
- * IO to complete. Callers must hold the sb s_umount semaphore for
+ * This function initiates writeback and waits for the operation to
+ * complete. Callers must hold the sb s_umount semaphore for
* reading, to avoid having the super disappear before we are done.
*/
-static void bdi_sync_writeback(struct backing_dev_info *bdi,
- struct super_block *sb)
+static void bdi_queue_work_onstack(struct wb_writeback_args *args)
{
- struct wb_writeback_args args = {
- .sb = sb,
- .sync_mode = WB_SYNC_ALL,
- .nr_pages = LONG_MAX,
- .range_cyclic = 0,
- };
struct bdi_work work;
- bdi_work_init(&work, &args);
+ bdi_work_init(&work, args);
__set_bit(WS_ONSTACK, &work.state);
- bdi_queue_work(bdi, &work);
+ bdi_queue_work(args->sb->s_bdi, &work);
bdi_wait_on_work_done(&work);
}
@@ -944,7 +936,7 @@
/*
* Schedule writeback for all backing devices. This does WB_SYNC_NONE
- * writeback, for integrity writeback see bdi_sync_writeback().
+ * writeback, for integrity writeback see bdi_queue_work_onstack().
*/
static void bdi_writeback_all(struct super_block *sb, long nr_pages)
{
@@ -1183,12 +1175,15 @@
{
unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
- long nr_to_write;
+ struct wb_writeback_args args = {
+ .sb = sb,
+ .sync_mode = WB_SYNC_NONE,
+ };
- nr_to_write = nr_dirty + nr_unstable +
+ args.nr_pages = nr_dirty + nr_unstable +
(inodes_stat.nr_inodes - inodes_stat.nr_unused);
- bdi_start_writeback(sb->s_bdi, sb, nr_to_write);
+ bdi_queue_work_onstack(&args);
}
EXPORT_SYMBOL(writeback_inodes_sb);
@@ -1218,7 +1213,14 @@
*/
void sync_inodes_sb(struct super_block *sb)
{
- bdi_sync_writeback(sb->s_bdi, sb);
+ struct wb_writeback_args args = {
+ .sb = sb,
+ .sync_mode = WB_SYNC_ALL,
+ .nr_pages = LONG_MAX,
+ .range_cyclic = 0,
+ };
+
+ bdi_queue_work_onstack(&args);
wait_sb_inodes(sb);
}
EXPORT_SYMBOL(sync_inodes_sb);