btrfs: cleanup assigning next active device with a check
Creates helper fucntion as needed by the device delete
and replace operations. Also now it checks if the next
device being assigned is an active device.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 41bc384..3fb0786 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1756,10 +1756,49 @@
return 0;
}
+struct btrfs_device *btrfs_find_next_active_device(struct btrfs_fs_devices *fs_devs,
+ struct btrfs_device *device)
+{
+ struct btrfs_device *next_device;
+
+ list_for_each_entry(next_device, &fs_devs->devices, dev_list) {
+ if (next_device != device &&
+ !next_device->missing && next_device->bdev)
+ return next_device;
+ }
+
+ return NULL;
+}
+
+/*
+ * Helper function to check if the given device is part of s_bdev / latest_bdev
+ * and replace it with the provided or the next active device, in the context
+ * where this function called, there should be always be another device (or
+ * this_dev) which is active.
+ */
+void btrfs_assign_next_active_device(struct btrfs_fs_info *fs_info,
+ struct btrfs_device *device, struct btrfs_device *this_dev)
+{
+ struct btrfs_device *next_device;
+
+ if (this_dev)
+ next_device = this_dev;
+ else
+ next_device = btrfs_find_next_active_device(fs_info->fs_devices,
+ device);
+ ASSERT(next_device);
+
+ if (fs_info->sb->s_bdev &&
+ (fs_info->sb->s_bdev == device->bdev))
+ fs_info->sb->s_bdev = next_device->bdev;
+
+ if (fs_info->fs_devices->latest_bdev == device->bdev)
+ fs_info->fs_devices->latest_bdev = next_device->bdev;
+}
+
int btrfs_rm_device(struct btrfs_root *root, char *device_path, u64 devid)
{
struct btrfs_device *device;
- struct btrfs_device *next_device;
struct btrfs_fs_devices *cur_devices;
u64 num_devices;
int ret = 0;
@@ -1846,13 +1885,7 @@
if (device->missing)
device->fs_devices->missing_devices--;
- next_device = list_entry(root->fs_info->fs_devices->devices.next,
- struct btrfs_device, dev_list);
- if (root->fs_info->sb->s_bdev &&
- (root->fs_info->sb->s_bdev == device->bdev))
- root->fs_info->sb->s_bdev = next_device->bdev;
- if (device->bdev == root->fs_info->fs_devices->latest_bdev)
- root->fs_info->fs_devices->latest_bdev = next_device->bdev;
+ btrfs_assign_next_active_device(root->fs_info, device, NULL);
if (device->bdev) {
device->fs_devices->open_devices--;
@@ -1981,8 +2014,6 @@
void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
struct btrfs_device *tgtdev)
{
- struct btrfs_device *next_device;
-
mutex_lock(&uuid_mutex);
WARN_ON(!tgtdev);
mutex_lock(&fs_info->fs_devices->device_list_mutex);
@@ -1995,13 +2026,8 @@
}
fs_info->fs_devices->num_devices--;
- next_device = list_entry(fs_info->fs_devices->devices.next,
- struct btrfs_device, dev_list);
- if (fs_info->sb->s_bdev &&
- (tgtdev->bdev == fs_info->sb->s_bdev))
- fs_info->sb->s_bdev = next_device->bdev;
- if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
- fs_info->fs_devices->latest_bdev = next_device->bdev;
+ btrfs_assign_next_active_device(fs_info, tgtdev, NULL);
+
list_del_rcu(&tgtdev->dev_list);
call_rcu(&tgtdev->rcu, free_device);