Create a btrfs backing dev info

This allows intelligent versions of unplug and congestion functions

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d8474796dea2..6a70e4916ab4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -655,6 +655,55 @@ static int add_hasher(struct btrfs_fs_info *info, char *type) {
         return 0;
 }
 #endif
+
+static int btrfs_congested_fn(void *congested_data, int bdi_bits)
+{
+        struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
+        int ret = 0;
+        struct list_head *cur;
+        struct btrfs_device *device;
+        struct backing_dev_info *bdi;
+
+        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 && bdi_congested(bdi, bdi_bits)) {
+                        ret = 1;
+                        break;
+                }
+        }
+        return ret;
+}
+
+void btrfs_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);
+                }
+        }
+}
+
+static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
+{
+        bdi_init(bdi);
+        bdi->ra_pages   = default_backing_dev_info.ra_pages;
+        bdi->state              = 0;
+        bdi->capabilities       = default_backing_dev_info.capabilities;
+        bdi->unplug_io_fn       = btrfs_unplug_io_fn;
+        bdi->unplug_io_data     = info;
+        bdi->congested_fn       = btrfs_congested_fn;
+        bdi->congested_data     = info;
+        return 0;
+}
+
 struct btrfs_root *open_ctree(struct super_block *sb,
                               struct btrfs_fs_devices *fs_devices)
 {
@@ -708,11 +757,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         fs_info->max_extent = (u64)-1;
         fs_info->max_inline = 8192 * 1024;
         fs_info->delalloc_bytes = 0;
+        setup_bdi(fs_info, &fs_info->bdi);
         fs_info->btree_inode = new_inode(sb);
         fs_info->btree_inode->i_ino = 1;
         fs_info->btree_inode->i_nlink = 1;
         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
+        fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
+
         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
                              fs_info->btree_inode->i_mapping,
                              GFP_NOFS);
@@ -992,6 +1044,7 @@ int close_ctree(struct btrfs_root *root)
 #endif
         close_all_devices(fs_info);
         btrfs_mapping_tree_free(&fs_info->mapping_tree);
+        bdi_destroy(&fs_info->bdi);
 
         kfree(fs_info->extent_root);
         kfree(fs_info->tree_root);