Btrfs: Fix btrfs_drop_extent_cache for skip pinned case

The check for skip pinned case is wrong, it may breaks the
while loop too soon.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3d2e45ce5d25..3bfe9f03990b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -179,18 +179,14 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                 }
                 flags = em->flags;
                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
-                        if (em->start <= start &&
-                            (!testend || em->start + em->len >= start + len)) {
+                        if (testend && em->start + em->len >= start + len) {
                                 free_extent_map(em);
                                 write_unlock(&em_tree->lock);
                                 break;
                         }
-                        if (start < em->start) {
-                                len = em->start - start;
-                        } else {
+                        start = em->start + em->len;
+                        if (testend)
                                 len = start + len - (em->start + em->len);
-                                start = em->start + em->len;
-                        }
                         free_extent_map(em);
                         write_unlock(&em_tree->lock);
                         continue;