Btrfs: Fix hole insertion corner cases

There were a few places that could cause duplicate extent insertion,
this adjusts the code that creates holes to avoid it.

lookup_extent_map is changed to correctly return all of the extents in a
range, even when there are none matching at the start of the range.

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

1 files changed, 77 insertions, 1 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 897242e..1cd8c90 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -278,7 +278,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 		u64 hole_size;
 		u64 mask = root->sectorsize - 1;
 		last_pos_in_file = (isize + mask) & ~mask;
-		hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
+		hole_size = (end_pos - last_pos_in_file + mask) & ~mask;
 
 		if (last_pos_in_file < start_pos) {
 			err = btrfs_drop_extents(trans, root, inode,
@@ -293,6 +293,7 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 						       inode->i_ino,
 						       last_pos_in_file,
 						       0, 0, hole_size);
+			btrfs_check_file(root, inode);
 		}
 		if (err)
 			goto failed;
@@ -378,6 +379,80 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
 	return 0;
 }
 
+int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
+{
+	return 0;
+#if 0
+	struct btrfs_path *path;
+	struct btrfs_key found_key;
+	struct extent_buffer *leaf;
+	struct btrfs_file_extent_item *extent;
+	u64 last_offset = 0;
+	int nritems;
+	int slot;
+	int found_type;
+	int ret;
+	int err = 0;
+	u64 extent_end = 0;
+
+	path = btrfs_alloc_path();
+	ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
+				       last_offset, 0);
+	while(1) {
+		nritems = btrfs_header_nritems(path->nodes[0]);
+		if (path->slots[0] >= nritems) {
+			ret = btrfs_next_leaf(root, path);
+			if (ret)
+				goto out;
+			nritems = btrfs_header_nritems(path->nodes[0]);
+		}
+		slot = path->slots[0];
+		leaf = path->nodes[0];
+		btrfs_item_key_to_cpu(leaf, &found_key, slot);
+		if (found_key.objectid != inode->i_ino)
+			break;
+		if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+			goto out;
+
+		if (found_key.offset != last_offset) {
+			WARN_ON(1);
+			btrfs_print_leaf(root, leaf);
+			printk("inode %lu found offset %Lu expected %Lu\n",
+			       inode->i_ino, found_key.offset, last_offset);
+			err = 1;
+			goto out;
+		}
+		extent = btrfs_item_ptr(leaf, slot,
+					struct btrfs_file_extent_item);
+		found_type = btrfs_file_extent_type(leaf, extent);
+		if (found_type == BTRFS_FILE_EXTENT_REG) {
+			extent_end = found_key.offset +
+			     btrfs_file_extent_num_bytes(leaf, extent);
+		} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+			struct btrfs_item *item;
+			item = btrfs_item_nr(leaf, slot);
+			extent_end = found_key.offset +
+			     btrfs_file_extent_inline_len(leaf, item);
+			extent_end = (extent_end + root->sectorsize - 1) &
+				~((u64)root->sectorsize -1 );
+		}
+		last_offset = extent_end;
+		path->slots[0]++;
+	}
+	if (last_offset < inode->i_size) {
+		WARN_ON(1);
+		btrfs_print_leaf(root, leaf);
+		printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
+		       last_offset, inode->i_size);
+		err = 1;
+
+	}
+out:
+	btrfs_free_path(path);
+	return err;
+#endif
+}
+
 /*
  * this is very complex, but the basic idea is to drop all extents
  * in the range start - end.  hint_block is filled in with a block number
@@ -436,6 +511,7 @@ next_slot:
 		slot = path->slots[0];
 		ret = 0;
 		btrfs_item_key_to_cpu(leaf, &key, slot);
+
 		if (key.offset >= end || key.objectid != inode->i_ino) {
 			goto out;
 		}