Re: [PATCH] btrfs: check file extent backref offset underflow
From: Li Zefan <hidden>
Date: 2011-08-29 01:59:13
Yan, Zheng wrote:
Offset field in data extent backref can underflow if clone range ioctl is used. We can reliably detect the underflow because max file size is limited to 2^63 and max data extent size is limited by block group size. Signed-off-by: Zheng Yan <redacted>
Tested-by: Li Zefan <redacted> ...
quoted hunk ↗ jump to hunk
@@ -3323,8 +3323,11 @@ static int find_data_references(struct reloc_control *rc, } key.objectid = ref_objectid; - key.offset = ref_offset; key.type = BTRFS_EXTENT_DATA_KEY; + if (ref_offset > ((u64)-1 << 32)) + key.offset = 0; + else + key.offset = ref_offset;
This needs comment, as we're working around a corner case and a magic number is used.
path->search_commit_root = 1; path->skip_locking = 1; --