Deal with page == NULL in the btrfs_unplug_io_fn
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7f5aca3..19c258d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -911,12 +911,40 @@
return ret;
}
+/*
+ * this unplugs every device on the box, and it is only used when page
+ * is null
+ */
+static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
+{
+ struct list_head *cur;
+ struct btrfs_device *device;
+ struct btrfs_fs_info *info;
+
+ info = (struct btrfs_fs_info *)bdi->unplug_io_data;
+ list_for_each(cur, &info->fs_devices->devices) {
+ device = list_entry(cur, struct btrfs_device, dev_list);
+ bdi = blk_get_backing_dev_info(device->bdev);
+ if (bdi->unplug_io_fn) {
+ bdi->unplug_io_fn(bdi, page);
+ }
+ }
+}
+
void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
{
- struct inode *inode = page->mapping->host;
+ struct inode *inode;
struct extent_map_tree *em_tree;
struct extent_map *em;
- u64 offset = page_offset(page);
+ u64 offset;
+
+ if (!page) {
+ __unplug_io_fn(bdi, page);
+ return;
+ }
+
+ inode = page->mapping->host;
+ offset = page_offset(page);
em_tree = &BTRFS_I(inode)->extent_tree;
spin_lock(&em_tree->lock);