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btrfs: Round down values which are written for total_bytes_size

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We got an internal report about a file system not wanting to mount
following 99e3ecfcb9 ("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 <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2017-06-16 14:39:20 +03:00 committed by David Sterba
parent eca152edf5
commit 7dfb8be11b
2 changed files with 14 additions and 5 deletions
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1
fs/btrfs/ctree.h
View File

@ -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);
}

18
fs/btrfs/volumes.c
View File

@ -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. */