Merge tag 'block-5.7-2020-05-29' of git://git.kernel.dk/linux-block

[tomoyo/tomoyo-test1.git] / fs / btrfs / tree-log.c

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index ec36a7c..02ebdd9 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4226,6 +4226,9 @@ static int btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans,
        const u64 ino = btrfs_ino(inode);
        struct btrfs_path *dst_path = NULL;
        bool dropped_extents = false;
+       u64 truncate_offset = i_size;
+       struct extent_buffer *leaf;
+       int slot;
        int ins_nr = 0;
        int start_slot;
        int ret;
@@ -4240,9 +4243,43 @@ static int btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans,
        if (ret < 0)
                goto out;
 
+       /*
+        * We must check if there is a prealloc extent that starts before the
+        * i_size and crosses the i_size boundary. This is to ensure later we
+        * truncate down to the end of that extent and not to the i_size, as
+        * otherwise we end up losing part of the prealloc extent after a log
+        * replay and with an implicit hole if there is another prealloc extent
+        * that starts at an offset beyond i_size.
+        */
+       ret = btrfs_previous_item(root, path, ino, BTRFS_EXTENT_DATA_KEY);
+       if (ret < 0)
+               goto out;
+
+       if (ret == 0) {
+               struct btrfs_file_extent_item *ei;
+
+               leaf = path->nodes[0];
+               slot = path->slots[0];
+               ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+
+               if (btrfs_file_extent_type(leaf, ei) ==
+                   BTRFS_FILE_EXTENT_PREALLOC) {
+                       u64 extent_end;
+
+                       btrfs_item_key_to_cpu(leaf, &key, slot);
+                       extent_end = key.offset +
+                               btrfs_file_extent_num_bytes(leaf, ei);
+
+                       if (extent_end > i_size)
+                               truncate_offset = extent_end;
+               }
+       } else {
+               ret = 0;
+       }
+
        while (true) {
-               struct extent_buffer *leaf = path->nodes[0];
-               int slot = path->slots[0];
+               leaf = path->nodes[0];
+               slot = path->slots[0];
 
                if (slot >= btrfs_header_nritems(leaf)) {
                        if (ins_nr > 0) {
@@ -4280,7 +4317,7 @@ static int btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans,
                                ret = btrfs_truncate_inode_items(trans,
                                                         root->log_root,
                                                         &inode->vfs_inode,
-                                                        i_size,
+                                                        truncate_offset,
                                                         BTRFS_EXTENT_DATA_KEY);
                        } while (ret == -EAGAIN);
                        if (ret)