Merge tag 'for-4.20-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...

Pull btrfs fixes from David Sterba:
 "Some of these bugs are being hit during testing so we'd like to get
  them merged, otherwise there are usual stability fixes for stable
  trees"

* tag 'for-4.20-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: relocation: set trans to be NULL after ending transaction
  Btrfs: fix race between enabling quotas and subvolume creation
  Btrfs: send, fix infinite loop due to directory rename dependencies
  Btrfs: ensure path name is null terminated at btrfs_control_ioctl
  Btrfs: fix rare chances for data loss when doing a fast fsync
  btrfs: Always try all copies when reading extent buffers

diff --combined fs/btrfs/file.c
index a3c22e1,b92b7f0..58e93bc
--- 1/fs/btrfs/file.c
--- 2/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@@ -2088,6 -2088,30 +2088,30 @@@ int btrfs_sync_file(struct file *file, 
  
        atomic_inc(&root->log_batch);
  
+       /*
+        * Before we acquired the inode's lock, someone may have dirtied more
+        * pages in the target range. We need to make sure that writeback for
+        * any such pages does not start while we are logging the inode, because
+        * if it does, any of the following might happen when we are not doing a
+        * full inode sync:
+        *
+        * 1) We log an extent after its writeback finishes but before its
+        *    checksums are added to the csum tree, leading to -EIO errors
+        *    when attempting to read the extent after a log replay.
+        *
+        * 2) We can end up logging an extent before its writeback finishes.
+        *    Therefore after the log replay we will have a file extent item
+        *    pointing to an unwritten extent (and no data checksums as well).
+        *
+        * So trigger writeback for any eventual new dirty pages and then we
+        * wait for all ordered extents to complete below.
+        */
+       ret = start_ordered_ops(inode, start, end);
+       if (ret) {
+               inode_unlock(inode);
+               goto out;
+       }
+ 
        /*
         * We have to do this here to avoid the priority inversion of waiting on
         * IO of a lower priority task while holding a transaciton open.
@@@ -3298,7 -3322,8 +3322,7 @@@ const struct file_operations btrfs_file
  #ifdef CONFIG_COMPAT
        .compat_ioctl   = btrfs_compat_ioctl,
  #endif
 -      .clone_file_range = btrfs_clone_file_range,
 -      .dedupe_file_range = btrfs_dedupe_file_range,
 +      .remap_file_range = btrfs_remap_file_range,
  };
  
  void __cold btrfs_auto_defrag_exit(void)