vfs: Move noop_backing_dev_info check from sync into writeback
In principle, a filesystem may want to have ->sync_fs() called during sync(1)
although it does not have a bdi (i.e. s_bdi is set to noop_backing_dev_info).
Only writeback code really needs bdi set to something reasonable. So move the
checks where they are more logical.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 41a3ccf..8f660dd 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1315,6 +1315,8 @@
.reason = reason,
};
+ if (sb->s_bdi == &noop_backing_dev_info)
+ return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
bdi_queue_work(sb->s_bdi, &work);
wait_for_completion(&done);
@@ -1398,6 +1400,9 @@
.reason = WB_REASON_SYNC,
};
+ /* Nothing to do? */
+ if (sb->s_bdi == &noop_backing_dev_info)
+ return;
WARN_ON(!rwsem_is_locked(&sb->s_umount));
bdi_queue_work(sb->s_bdi, &work);
diff --git a/fs/sync.c b/fs/sync.c
index 11e3d1c..b3d2a00 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -29,13 +29,6 @@
*/
static int __sync_filesystem(struct super_block *sb, int wait)
{
- /*
- * This should be safe, as we require bdi backing to actually
- * write out data in the first place
- */
- if (sb->s_bdi == &noop_backing_dev_info)
- return 0;
-
if (sb->s_qcop && sb->s_qcop->quota_sync)
sb->s_qcop->quota_sync(sb, -1, wait);
