Btrfs: When shrinking, only update disk size on success
Previously, we updated a device's size prior to attempting a shrink
operation. This patch moves the device resizing logic to only happen if
the shrink completes successfully. In the process, it introduces a new
field to btrfs_device -- disk_total_bytes -- to track the on-disk size.
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e53835b..5f01dad 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1543,7 +1543,7 @@
btrfs_set_device_io_align(leaf, dev_item, device->io_align);
btrfs_set_device_io_width(leaf, dev_item, device->io_width);
btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
- btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
+ btrfs_set_device_total_bytes(leaf, dev_item, device->disk_total_bytes);
btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
btrfs_mark_buffer_dirty(leaf);
@@ -1940,14 +1940,6 @@
device->total_bytes = new_size;
if (device->writeable)
device->fs_devices->total_rw_bytes -= diff;
- ret = btrfs_update_device(trans, device);
- if (ret) {
- unlock_chunks(root);
- btrfs_end_transaction(trans, root);
- goto done;
- }
- WARN_ON(diff > old_total);
- btrfs_set_super_total_bytes(super_copy, old_total - diff);
unlock_chunks(root);
btrfs_end_transaction(trans, root);
@@ -1979,7 +1971,7 @@
length = btrfs_dev_extent_length(l, dev_extent);
if (key.offset + length <= new_size)
- goto done;
+ break;
chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
@@ -1992,6 +1984,26 @@
goto done;
}
+ /* Shrinking succeeded, else we would be at "done". */
+ trans = btrfs_start_transaction(root, 1);
+ if (!trans) {
+ ret = -ENOMEM;
+ goto done;
+ }
+ lock_chunks(root);
+
+ device->disk_total_bytes = new_size;
+ /* Now btrfs_update_device() will change the on-disk size. */
+ ret = btrfs_update_device(trans, device);
+ if (ret) {
+ unlock_chunks(root);
+ btrfs_end_transaction(trans, root);
+ goto done;
+ }
+ WARN_ON(diff > old_total);
+ btrfs_set_super_total_bytes(super_copy, old_total - diff);
+ unlock_chunks(root);
+ btrfs_end_transaction(trans, root);
done:
btrfs_free_path(path);
return ret;
@@ -3076,7 +3088,8 @@
unsigned long ptr;
device->devid = btrfs_device_id(leaf, dev_item);
- device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
+ device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
+ device->total_bytes = device->disk_total_bytes;
device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
device->type = btrfs_device_type(leaf, dev_item);
device->io_align = btrfs_device_io_align(leaf, dev_item);