Dongsheng Yang
2014-Oct-27 12:38 UTC
[PATCH] btrfs: get the accurate value of used_bytes in btrfs_get_block_group_info().
Reproducer: # mkfs.btrfs -f -b 20G /dev/sdb # mount /dev/sdb /mnt/test # fallocate -l 17G /mnt/test/largefile # btrfs fi df /mnt/test Data, single: total=17.49GiB, used=6.00GiB <- only 6G, but actually it should be 17G. System, DUP: total=8.00MiB, used=16.00KiB System, single: total=4.00MiB, used=0.00B Metadata, DUP: total=1.00GiB, used=112.00KiB Metadata, single: total=8.00MiB, used=0.00B GlobalReserve, single: total=16.00MiB, used=0.00B # sync # btrfs fi df /mnt/test Data, single: total=17.49GiB, used=17.00GiB <- After sync, it is expected. System, DUP: total=8.00MiB, used=16.00KiB System, single: total=4.00MiB, used=0.00B Metadata, DUP: total=1.00GiB, used=112.00KiB Metadata, single: total=8.00MiB, used=0.00B GlobalReserve, single: total=16.00MiB, used=0.00B The value of 6.00GiB is actually calculated in btrfs_get_block_group_info() by adding the @block_group->item->used for each group together. In this way, it did not consider the bytes in cache. This patch adds the value of @pinned, @reserved and @bytes_super in struct btrfs_block_group_cache to make sure we can get the accurate @used_bytes. Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> --- fs/btrfs/ioctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 33c80f5..bc2aaeb 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3892,6 +3892,10 @@ void btrfs_get_block_group_info(struct list_head *groups_list, space->total_bytes += block_group->key.offset; space->used_bytes + btrfs_block_group_used(&block_group->item); + /* Add bytes-info in cache */ + space->used_bytes += block_group->pinned; + space->used_bytes += block_group->reserved; + space->used_bytes += block_group->bytes_super; } } -- 1.8.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html