Some time back, nfsd switched from calling vfs_fsync() to using a new
commit_metadata() hook in export_operations(). If the file system did
not provide a commit_metadata() hook, it fell back to using
sync_inode_metadata(). Unfortunately doesn't work on all file
systems. In particular, it doesn't work on ext4 due to how the inode
gets journalled --- the VFS writeback code will not always call
ext4_write_inode().
So we need to provide our own ext4_nfs_commit_metdata() method which
calls ext4_write_inode() directly.
Google-Bug-Id: 121195940
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
fde872682e