Btrfs: add two more find_device() methods
The new function btrfs_find_device_missing_or_by_path() will be
used for the device replace procedure. This function itself calls
the second new function btrfs_find_device_by_path().
Unfortunately, it is not possible to currently make the rest of the
code use these functions as well, since all functions that look
similar at first view are all a little bit different in what they
are doing. But in the future, new code could benefit from these
two new functions, and currently, device replace uses them.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4def1fd..1483041 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1522,6 +1522,65 @@
goto error_brelse;
}
+int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
+ struct btrfs_device **device)
+{
+ int ret = 0;
+ struct btrfs_super_block *disk_super;
+ u64 devid;
+ u8 *dev_uuid;
+ struct block_device *bdev;
+ struct buffer_head *bh;
+
+ *device = NULL;
+ ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
+ root->fs_info->bdev_holder, 0, &bdev, &bh);
+ if (ret)
+ return ret;
+ disk_super = (struct btrfs_super_block *)bh->b_data;
+ devid = btrfs_stack_device_id(&disk_super->dev_item);
+ dev_uuid = disk_super->dev_item.uuid;
+ *device = btrfs_find_device(root, devid, dev_uuid,
+ disk_super->fsid);
+ brelse(bh);
+ if (!*device)
+ ret = -ENOENT;
+ blkdev_put(bdev, FMODE_READ);
+ return ret;
+}
+
+int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
+ char *device_path,
+ struct btrfs_device **device)
+{
+ *device = NULL;
+ if (strcmp(device_path, "missing") == 0) {
+ struct list_head *devices;
+ struct btrfs_device *tmp;
+
+ devices = &root->fs_info->fs_devices->devices;
+ /*
+ * It is safe to read the devices since the volume_mutex
+ * is held by the caller.
+ */
+ list_for_each_entry(tmp, devices, dev_list) {
+ if (tmp->in_fs_metadata && !tmp->bdev) {
+ *device = tmp;
+ break;
+ }
+ }
+
+ if (!*device) {
+ pr_err("btrfs: no missing device found\n");
+ return -ENOENT;
+ }
+
+ return 0;
+ } else {
+ return btrfs_find_device_by_path(root, device_path, device);
+ }
+}
+
/*
* does all the dirty work required for changing file system's UUID.
*/
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 1789cda..657bb12 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -268,6 +268,11 @@
struct btrfs_fs_devices **fs_devices_ret);
int btrfs_close_devices(struct btrfs_fs_devices *fs_devices);
void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices);
+int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
+ char *device_path,
+ struct btrfs_device **device);
+int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
+ struct btrfs_device **device);
int btrfs_add_device(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_device *device);