Btrfs: incompatible format change to remove hole extents

Btrfs has always had these filler extent data items for holes in inodes.  This
has made somethings very easy, like logging hole punches and sending hole
punches.  However for large holey files these extent data items are pure
overhead.  So add an incompatible feature to no longer add hole extents to
reduce the amount of metadata used by these sort of files.  This has a few
changes for logging and send obviously since they will need to detect holes and
log/send the holes if there are any.  I've tested this thoroughly with xfstests
and it doesn't cause any issues with and without the incompat format set.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 316136bd6dd7..bcd0bd85e3ed 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -41,7 +41,6 @@ static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
                     int level, int slot);
 static void tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
                                  struct extent_buffer *eb);
-static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
 
 struct btrfs_path *btrfs_alloc_path(void)
 {
@@ -4817,7 +4816,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
  * This may release the path, and so you may lose any locks held at the
  * time you call it.
  */
-static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
+int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
         struct btrfs_key key;
         struct btrfs_disk_key found_key;