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>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fe9eb99..6826018 100644 (file)
--- 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;
                }