From 7dfb8be11b5d1db4325414ce16b8c164e08f52d8 Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Fri, 16 Jun 2017 14:39:20 +0300 Subject: [PATCH] btrfs: Round down values which are written for total_bytes_size We got an internal report about a file system not wanting to mount following 99e3ecfcb9f4 ("Btrfs: add more validation checks for superblock"). BTRFS error (device sdb1): super_total_bytes 1000203816960 mismatch with fs_devices total_rw_bytes 1000203820544 Subtracting the numbers we get a difference of less than a 4kb. Upon closer inspection it became apparent that mkfs actually rounds down the size of the device to a multiple of sector size. However, the same cannot be said for various functions which modify the total size and are called from btrfs_balance as well as when adding a new device. So this patch ensures that values being saved into on-disk data structures are always rounded down to a multiple of sectorsize. Signed-off-by: Nikolay Borisov Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 1 + fs/btrfs/volumes.c | 18 +++++++++++++----- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index b31515a2ef71..15a77e64dc20 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1556,6 +1556,7 @@ static inline void btrfs_set_device_total_bytes(struct extent_buffer *eb, { BUILD_BUG_ON(sizeof(u64) != sizeof(((struct btrfs_dev_item *)0))->total_bytes); + WARN_ON(!IS_ALIGNED(val, eb->fs_info->sectorsize)); btrfs_set_64(eb, s, offsetof(struct btrfs_dev_item, total_bytes), val); } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index fa3c6412be72..2090245e8f06 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2385,7 +2385,8 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path device->io_width = fs_info->sectorsize; device->io_align = fs_info->sectorsize; device->sector_size = fs_info->sectorsize; - device->total_bytes = i_size_read(bdev->bd_inode); + device->total_bytes = round_down(i_size_read(bdev->bd_inode), + fs_info->sectorsize); device->disk_total_bytes = device->total_bytes; device->commit_total_bytes = device->total_bytes; device->fs_info = fs_info; @@ -2422,7 +2423,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path tmp = btrfs_super_total_bytes(fs_info->super_copy); btrfs_set_super_total_bytes(fs_info->super_copy, - tmp + device->total_bytes); + round_down(tmp + device->total_bytes, fs_info->sectorsize)); tmp = btrfs_super_num_devices(fs_info->super_copy); btrfs_set_super_num_devices(fs_info->super_copy, tmp + 1); @@ -2685,6 +2686,8 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans, if (!device->writeable) return -EACCES; + new_size = round_down(new_size, fs_info->sectorsize); + mutex_lock(&fs_info->chunk_mutex); old_total = btrfs_super_total_bytes(super_copy); diff = new_size - device->total_bytes; @@ -2697,7 +2700,8 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans, fs_devices = fs_info->fs_devices; - btrfs_set_super_total_bytes(super_copy, old_total + diff); + btrfs_set_super_total_bytes(super_copy, + round_down(old_total + diff, fs_info->sectorsize)); device->fs_devices->total_rw_bytes += diff; btrfs_device_set_total_bytes(device, new_size); @@ -4387,7 +4391,10 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size) struct btrfs_super_block *super_copy = fs_info->super_copy; u64 old_total = btrfs_super_total_bytes(super_copy); u64 old_size = btrfs_device_get_total_bytes(device); - u64 diff = old_size - new_size; + u64 diff; + + new_size = round_down(new_size, fs_info->sectorsize); + diff = old_size - new_size; if (device->is_tgtdev_for_dev_replace) return -EINVAL; @@ -4514,7 +4521,8 @@ again: &fs_info->fs_devices->resized_devices); WARN_ON(diff > old_total); - btrfs_set_super_total_bytes(super_copy, old_total - diff); + btrfs_set_super_total_bytes(super_copy, + round_down(old_total - diff, fs_info->sectorsize)); mutex_unlock(&fs_info->chunk_mutex); /* Now btrfs_update_device() will change the on-disk size. */