writeback: check for registered bdi in flusher add and inode dirty
Also a debugging aid. We want to catch dirty inodes being added to
backing devices that don't do writeback.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2e601ce..da86ef5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1046,6 +1046,14 @@
*/
if (!was_dirty) {
struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
+ struct backing_dev_info *bdi = wb->bdi;
+
+ if (bdi_cap_writeback_dirty(bdi) &&
+ !test_bit(BDI_registered, &bdi->state)) {
+ WARN_ON(1);
+ printk(KERN_ERR "bdi-%s not registered\n",
+ bdi->name);
+ }
inode->dirtied_when = jiffies;
list_move(&inode->i_list, &wb->b_dirty);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 2f218b7..f169bcb 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -29,6 +29,7 @@
BDI_wb_alloc, /* Default embedded wb allocated */
BDI_async_congested, /* The async (write) queue is getting full */
BDI_sync_congested, /* The sync queue is getting full */
+ BDI_registered, /* bdi_register() was done */
BDI_unused, /* Available bits start here */
};
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 5cb32c5..d3ca0da 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -465,6 +465,12 @@
if (!bdi_cap_writeback_dirty(bdi))
return;
+ if (WARN_ON(!test_bit(BDI_registered, &bdi->state))) {
+ printk(KERN_ERR "bdi %p/%s is not registered!\n",
+ bdi, bdi->name);
+ return;
+ }
+
/*
* Check with the helper whether to proceed adding a task. Will only
* abort if we two or more simultanous calls to
@@ -528,6 +534,7 @@
}
bdi_debug_register(bdi, dev_name(dev));
+ set_bit(BDI_registered, &bdi->state);
exit:
return ret;
}