a6f93c71d4
We've avoided data losing raid profile when doing balance, but it
turns out that deleting a device could also result in the same
problem.
Say we have 3 disks, and they're created with '-d raid1' profile.
- We have chunk P (the only data chunk on the empty btrfs).
- Suppose that chunk P's two raid1 copies reside in disk A and disk B.
- Now, 'btrfs device remove disk B'
btrfs_rm_device()
-> btrfs_shrink_device()
-> btrfs_relocate_chunk() #relocate any chunk on disk B
to other places.
- Chunk P will be removed and a new chunk will be created to hold
those data, but as chunk P is the only one holding raid1 profile,
after it goes away, the new chunk will be created as single profile
which is our default profile.
This fixes the problem by creating an empty data chunk before
relocating the data chunk.
Metadata/System chunk are supposed to have non-zero bytes all the time
so their raid profile is preserved.
Reported-by: James Alandt <James.Alandt@wdc.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.