btrfs_drop_extents: make sure the item is getting smaller before truncate

Signed-off-by: Chris Mason <chris.mason@oracle.com>

3 files changed, 24 insertions, 16 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 56b977ffe918..b29b911dd825 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1037,7 +1037,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end);
 extern struct file_operations btrfs_file_operations;
 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
-                       u64 start, u64 end, u64 inline_end, u64 *hint_block);
+                       u64 start, u64 end, u64 inline_limit, u64 *hint_block);
 /* tree-defrag.c */
 int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
                         struct btrfs_root *root, int cache_only);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3c00f967eccb..55abdf997ca5 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -45,6 +45,9 @@ static int cache_block_group(struct btrfs_root *root,
         u64 first_free;
         int found = 0;
 
+        if (!block_group)
+                return 0;
+
         root = root->fs_info->extent_root;
         free_space_cache = &root->fs_info->free_space_cache;
 
@@ -168,6 +171,11 @@ static u64 find_search_start(struct btrfs_root *root,
         u64 cache_miss = 0;
         int wrapped = 0;
 
+        if (!cache) {
+                cache = btrfs_lookup_block_group(root->fs_info, search_start);
+                if (!cache)
+                        return search_start;
+        }
 again:
         ret = cache_block_group(root, cache);
         if (ret)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index ba624ae16e61..b0d637787264 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -377,23 +377,23 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
  */
 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
-                       u64 start, u64 end, u64 inline_end, u64 *hint_byte)
+                       u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
 {
-        int ret;
-        struct btrfs_key key;
+        u64 extent_end = 0;
+        u64 search_start = start;
         struct extent_buffer *leaf;
-        int slot;
         struct btrfs_file_extent_item *extent;
-        u64 extent_end = 0;
-        int keep;
-        struct btrfs_file_extent_item old;
         struct btrfs_path *path;
-        u64 search_start = start;
+        struct btrfs_key key;
+        struct btrfs_file_extent_item old;
+        int keep;
+        int slot;
         int bookend;
         int found_type;
         int found_extent;
         int found_inline;
         int recow;
+        int ret;
 
         btrfs_drop_extent_cache(inode, start, end - 1);
 
@@ -502,7 +502,7 @@ next_slot:
                         }
                         bookend = 1;
                         if (found_inline && start <= key.offset &&
-                            inline_end < extent_end)
+                            inline_limit < extent_end)
                                 keep = 1;
                 }
                 /* truncate existing extent */
@@ -526,12 +526,12 @@ next_slot:
                                 btrfs_set_file_extent_num_bytes(leaf, extent,
                                                                 new_num);
                                 btrfs_mark_buffer_dirty(leaf);
-                        } else if (end > extent_end &&
-                                   key.offset < inline_end &&
-                                   inline_end < extent_end) {
+                        } else if (key.offset < inline_limit &&
+                                   (end > extent_end) &&
+                                   (inline_limit < extent_end)) {
                                 u32 new_size;
                                 new_size = btrfs_file_extent_calc_inline_size(
-                                                   inline_end - key.offset);
+                                                   inline_limit - key.offset);
                                 btrfs_truncate_item(trans, root, path,
                                                     new_size, 1);
                         }
@@ -575,10 +575,10 @@ next_slot:
                                 continue;
                 }
                 if (bookend && found_inline && start <= key.offset &&
-                    inline_end < extent_end) {
+                    inline_limit < extent_end && key.offset <= inline_limit) {
                         u32 new_size;
                         new_size = btrfs_file_extent_calc_inline_size(
-                                                   extent_end - inline_end);
+                                                   extent_end - inline_limit);
                         btrfs_truncate_item(trans, root, path, new_size, 0);
                 }
                 /* create bookend, splitting the extent in two */