[PATCH v3 3/3] btrfs: update stripe_extent delete loop assumptions

[Johannes Thumshirn <jth@kernel.org>]

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

btrfs_delete_raid_extent() was written under the assumption, that it's
call-chain always passes a start, length tuple that matches a single
extent. But btrfs_delete_raid_extent() is called by
do_free_extent_acounting() which in term is called by
__btrfs_free_extent().

But this call-chain passes in a start address and a length that can
possibly match multiple on-disk extents.

To make this possible, we have to adjust the start and length of each
btree node lookup, to not delete beyond the requested range.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/raid-stripe-tree.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/btrfs/raid-stripe-tree.c b/fs/btrfs/raid-stripe-tree.c
index 53ca2c1a32ac..684d4744f02d 100644
--- a/fs/btrfs/raid-stripe-tree.c
+++ b/fs/btrfs/raid-stripe-tree.c
@@ -66,6 +66,11 @@ int btrfs_delete_raid_extent(struct btrfs_trans_handle *trans, u64 start, u64 le
 		if (ret)
 			break;
 
+		start += key.offset;
+		length -= key.offset;
+		if (length == 0)
+			break;
+
 		btrfs_release_path(path);
 	}
 

-- 
2.43.0