On Sat, Sep 23, 2017 at 03:22:36PM +0800, Qu Wenruo wrote: > >>> --- a/fs/btrfs/volumes.c > >>> +++ b/fs/btrfs/volumes.c > >>> @@ -6472,15 +6472,23 @@ static int read_one_chunk(struct btrfs_fs_info > >>> *fs_info, struct btrfs_key *key, > >>> return 0; > >>> } > >>> > >>> -static void fill_device_from_item(struct extent_buffer *leaf, > >>> - struct btrfs_dev_item *dev_item, > >>> - struct btrfs_device *device) > >>> +static void fill_device_from_item(struct btrfs_fs_info *fs_info, > >>> + struct extent_buffer *leaf, > >>> + struct btrfs_dev_item *dev_item, > >>> + struct btrfs_device *device) > >>> { > >>> unsigned long ptr; > >>> > >>> device->devid = btrfs_device_id(leaf, dev_item); > >>> device->disk_total_bytes = btrfs_device_total_bytes(leaf, > >>> dev_item); > >>> device->total_bytes = device->disk_total_bytes; > >>> + if (!IS_ALIGNED(device->total_bytes, fs_info->sectorsize)) { > >>> + btrfs_warn(fs_info, > >>> + "devid %llu has unaligned total bytes %llu", > >>> + device->devid, device->disk_total_bytes); > >>> + btrfs_warn(fs_info, > >>> + "please shrink the device a little and resize back > >>> to fix it"); > >>> + } > >> > >> How about telling uses to know device->total_bytes should be alligned > >> to fs_info->sectorsize here? > >> > >> Thanks, > > > > I should make my comment clearer, sorry. > > > > === > > + if (!IS_ALIGNED(device->total_bytes, fs_info->sectorsize)) { > > + btrfs_warn(fs_info, > > + "devid %llu: total bytes %llu should be aligned to > > %u bytes", > > + device->devid, device->disk_total_bytes, > > fs_info->sectorsize); > > + btrfs_warn(fs_info, > > + "please shrink the device a little and resize back > > to fix it"); > > + } > > === > > That's better. > > But I'm also considering modifying the total_bytes directly here.
Yeah, I think it would be better to fix here, without a warning even. The rounding error is below 4k and nodesize, we would never use this space for block groups so no accidental data loss. > So that any time DEV_ITEM and super block get updated, new aligned value > will be written back to disk, and since the value is aligned in memory, > it won't cause WARN_ON() any longer. > > I'll test and check the code for confirmation before updating the patch. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html