[BUG]
Shinichiro reported that "mkfs.btrfs -m DUP" is doing repeated write
into the device.
For non-zoned device this is not a big deal, but for zoned device this
is critical, as zoned device doesn't support overwrite at all.
[CAUSE]
The problem is related to write_and_map_eb() call, since commit
2a93728391 ("btrfs-progs: use write_data_to_disk() to replace
write_extent_to_disk()"), we call write_data_to_disk() for metadata
write back.
But the problem is, write_data_to_disk() will call btrfs_map_block()
with rw = WRITE.
By that btrfs_map_block() will always return all stripes, while in
write_data_to_disk() we also iterate through each mirror of the range.
This results above repeated writeback.
[FIX]
Fix this problem by completely remove @mirror argument
from write_data_to_disk().
With extra comments to explicitly show that function will write to
all mirrors.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 2a93728391 ("btrfs-progs: use write_data_to_disk() to replace write_extent_to_disk()")
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fc6925bfd3