From: Hugh Dickins <[email protected]>
Port fix to the off-by-one in find_next_usable_block's memscan from ext2 to
ext4; but it didn't cause a serious problem for ext4 because the additional
ext4_test_allocatable check rescued it from the error.
[[email protected]: build fix]
Signed-off-by: Mingming Cao <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
fs/ext4/balloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN fs/ext4/balloc.c~ext4-balloc-fix-_with_rsv-freeze fs/ext4/balloc.c
--- a/fs/ext4/balloc.c~ext4-balloc-fix-_with_rsv-freeze
+++ a/fs/ext4/balloc.c
@@ -747,7 +747,7 @@ find_next_usable_block(ext4_grpblk_t sta
here = 0;
p = ((char *)bh->b_data) + (here >> 3);
- r = memscan(p, 0, (maxblocks - here + 7) >> 3);
+ r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3));
next = (r - ((char *)bh->b_data)) << 3;
if (next < maxblocks && next >= start && ext4_test_allocatable(next, bh))
_