When creating btrfs, mkfs.btrfs will firstly create a temporary system
chunk as basis, and then created needed trees or new devices.
However the layout temporary system chunk is hard-coded and uses
reserved [0, 1M) range of devid 1.
Change the temporary chunk layout from old:
0 1M 4M 5M
|<----------- temp chunk -------------->|
And it's 1:1 mapped, which means it's a SINGLE chunk,
and stripe offset is also 0.
to new layout:
0 1M 4M 5M
|<----------- temp chunk -------------->|
And still keeps the 1:1 mapping.
However this also affects btrfs_min_dev_size() which still assume
temporary chunks starts at device offset 0.
The problem can only be exposed by "-m single" or "-M" where we reuse the
temporary chunk.
With other meta profiles, system and meta chunks are allocated by later
btrfs_alloc_chunk() call, and old SINGLE chunks are removed, so it will
be no such problem for other meta profiles.
Reported-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
[ folded fix for the minimal device size calculation ]
Signed-off-by: David Sterba <dsterba@suse.com>
997f9977c2