Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation
The current RAID 5/6 recovery code isn't quite prepared to handle
missing devices. In particular, it expects a bio that we previously
attempted to use in the read path, meaning that it has valid pages
allocated. However, missing devices have a NULL blkdev, and we can't
call bio_add_page() on a bio with a NULL blkdev. We could do manual
manipulation of bio->bi_io_vec, but that's pretty gross. So instead, add
a separate path that allows us to manually add pages to the rbio.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a12c450..0381624 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2720,8 +2720,7 @@
goto rbio_out;
list_for_each_entry(spage, &sparity->spages, list)
- raid56_parity_add_scrub_pages(rbio, spage->page,
- spage->logical);
+ raid56_add_scrub_pages(rbio, spage->page, spage->logical);
scrub_pending_bio_inc(sctx);
raid56_parity_submit_scrub_rbio(rbio);