btrfs: add and use helper to assert an inode range is clean

We have four different scenarios where we don't expect to find ordered
extents after locking a file range:

1) During plain fallocate;
2) During hole punching;
3) During zero range;
4) During reflinks (both cloning and deduplication).

This is because in all these cases we follow the pattern:

1) Lock the inode's VFS lock in exclusive mode;

2) Lock the inode's i_mmap_lock in exclusive node, to serialize with
   mmap writes;

3) Flush delalloc in a file range and wait for all ordered extents
   to complete - both done through btrfs_wait_ordered_range();

4) Lock the file range in the inode's io_tree.

So add a helper that asserts that we don't have ordered extents for a
given range. Make the four scenarios listed above use this helper after
locking the respective file range.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9addfd5cdf4e..e43e7853f389 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3375,6 +3375,7 @@ void btrfs_inode_unlock(struct inode *inode, unsigned int ilock_flags);
 void btrfs_update_inode_bytes(struct btrfs_inode *inode,
 			      const u64 add_bytes,
 			      const u64 del_bytes);
+void btrfs_assert_inode_range_clean(struct btrfs_inode *inode, u64 start, u64 end);
 
 /* ioctl.c */
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);