btrfs: use extent_map_end() at btrfs_drop_extent_map_range()

Instead of open coding the end offset calculation of an extent map, use
the helper extent_map_end() and cache its result in a local variable,
since it's used several times.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 587e029..28c5e02 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -690,6 +690,7 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
        }
        while (1) {
                struct extent_map *em;
+               u64 em_end;
                u64 gen;
                unsigned long flags;
                bool ends_after_range = false;
@@ -710,7 +711,8 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
                        write_unlock(&em_tree->lock);
                        break;
                }
-               if (testend && em->start + em->len > start + len)
+               em_end = extent_map_end(em);
+               if (testend && em_end > start + len)
                        ends_after_range = true;
                if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
                        if (ends_after_range) {
@@ -718,9 +720,9 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
                                write_unlock(&em_tree->lock);
                                break;
                        }
-                       start = em->start + em->len;
+                       start = em_end;
                        if (testend)
-                               len = start + len - (em->start + em->len);
+                               len = start + len - em_end;
                        free_extent_map(em);
                        write_unlock(&em_tree->lock);
                        continue;
@@ -767,7 +769,7 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end,
                }
                if (ends_after_range) {
                        split->start = start + len;
-                       split->len = em->start + em->len - (start + len);
+                       split->len = em_end - (start + len);
                        split->block_start = em->block_start;
                        split->flags = flags;
                        split->compress_type = em->compress_type;