[U-Boot] [PATCH] fs: btrfs: Fix wrong comparison in logical to physical mapping

Marek BehĂșn marek.behun at nic.cz
Wed Jul 4 17:10:45 UTC 2018


The comparison
  logical > item->logical + item->length
in btrfs_map_logical_to_physical is wrong and should be instead
  logical >= item->logical + item->length
For example, if
  item->logical = 4096
  item->length = 4096
and we are looking for logical = 8192, it is not part of item (item is
[4096, 8191]). But the comparison is false and we think we have found
the correct item, although we should be searing in the right subtree.

This fixes some bugs I encountered.

Signed-off-by: Marek Behun <marek.behun at nic.cz>
---
 fs/btrfs/chunk-map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/chunk-map.c b/fs/btrfs/chunk-map.c
index beb6a4bb92..31619f6241 100644
--- a/fs/btrfs/chunk-map.c
+++ b/fs/btrfs/chunk-map.c
@@ -78,7 +78,7 @@ u64 btrfs_map_logical_to_physical(u64 logical)
 
 		if (item->logical > logical)
 			node = node->rb_left;
-		else if (logical > item->logical + item->length)
+		else if (logical > item->logical + item->length - 1)
 			node = node->rb_right;
 		else
 			return item->physical + logical - item->logical;
-- 
2.16.4



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