• Chris Mason's avatar
    Btrfs: Wait for IO on the block device inodes of newly added devices · 8c8bee1d
    Chris Mason authored
    btrfs-vol -a /dev/xxx will zero the first and last two MB of the device.
    The kernel code needs to wait for this IO to finish before it adds
    the device.
    btrfs metadata IO does not happen through the block device inode.  A
    separate address space is used, allowing the zero filled buffer heads in
    the block device inode to be written to disk after FS metadata starts
    going down to the disk via the btrfs metadata inode.
    The end result is zero filled metadata blocks after adding new devices
    into the filesystem.
    The fix is a simple filemap_write_and_wait on the block device inode
    before actually inserting it into the pool of available devices.
    Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>