btrfs: Fix set/clear_extent_bit for 'end == (u64)-1'

There are some 'start = state->end + 1;' like code in set_extent_bit
and clear_extent_bit. They overflow when end == (u64)-1.

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

1 files changed, 14 insertions, 4 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fe9eb990e443..68260180f587 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -476,6 +476,7 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
         struct extent_state *state;
         struct extent_state *prealloc = NULL;
         struct rb_node *node;
+        u64 last_end;
         int err;
         int set = 0;
 
@@ -498,6 +499,7 @@ again:
         if (state->start > end)
                 goto out;
         WARN_ON(state->end < start);
+        last_end = state->end;
 
         /*
          *     | ---- desired range ---- |
@@ -524,9 +526,11 @@ again:
                 if (err)
                         goto out;
                 if (state->end <= end) {
-                        start = state->end + 1;
                         set |= clear_state_bit(tree, state, bits,
                                         wake, delete);
+                        if (last_end == (u64)-1)
+                                goto out;
+                        start = last_end + 1;
                 } else {
                         start = state->start;
                 }
@@ -552,8 +556,10 @@ again:
                 goto out;
         }
 
-        start = state->end + 1;
         set |= clear_state_bit(tree, state, bits, wake, delete);
+        if (last_end == (u64)-1)
+                goto out;
+        start = last_end + 1;
         goto search_again;
 
 out:
@@ -707,8 +713,10 @@ again:
                         goto out;
                 }
                 set_state_bits(tree, state, bits);
-                start = state->end + 1;
                 merge_state(tree, state);
+                if (last_end == (u64)-1)
+                        goto out;
+                start = last_end + 1;
                 goto search_again;
         }
 
@@ -742,8 +750,10 @@ again:
                         goto out;
                 if (state->end <= end) {
                         set_state_bits(tree, state, bits);
-                        start = state->end + 1;
                         merge_state(tree, state);
+                        if (last_end == (u64)-1)
+                                goto out;
+                        start = last_end + 1;
                 } else {
                         start = state->start;
                 }