btrfs_drop_extents: make sure the item is getting smaller before truncate

[~andy/linux] / fs / btrfs / file.c

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index bb98f52f4ea4341af0013157275130c4745d654f..b0d637787264a16bc32cbd386749c69ebda1c93f 100644 (file)
--- 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);
 
@@ -439,6 +439,12 @@ next_slot:
                                                struct btrfs_file_extent_item);
                        found_type = btrfs_file_extent_type(leaf, extent);
                        if (found_type == BTRFS_FILE_EXTENT_REG) {
+                               extent_end =
+                                    btrfs_file_extent_disk_bytenr(leaf,
+                                                                  extent);
+                               if (extent_end)
+                                       *hint_byte = extent_end;
+
                                extent_end = key.offset +
                                     btrfs_file_extent_num_bytes(leaf, extent);
                                found_extent = 1;
@@ -475,8 +481,7 @@ next_slot:
                        search_start = (extent_end + mask) & ~mask;
                } else
                        search_start = extent_end;
-
-               if (end <= extent_end && start >= key.offset && found_inline) {
+               if (end < extent_end && start > key.offset && found_inline) {
                        *hint_byte = EXTENT_MAP_INLINE;
                }
                if (end < extent_end && end >= key.offset) {
@@ -497,7 +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 */
@@ -521,12 +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);
                        }
@@ -570,10 +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 */
@@ -762,7 +767,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                num_written += write_bytes;
 
                balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
-               btrfs_btree_balance_dirty(root, 1);
+               if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+                       btrfs_btree_balance_dirty(root, 1);
                cond_resched();
        }
        mutex_unlock(&inode->i_mutex);