Re: [PATCH, RFC] fs: only call sync_filesystem() when remounting read-only

On Thu, Mar 13, 2014 at 11:36:35AM +1100, Dave Chinner wrote:

IMO, I think that you should be looking to fix ext4 syncfs issues,
not changing the VFS behaviour that might cause subtle and unnoticed
problems for other filesystems. We should not be moving data
inegrity operations without first auditing of all the filesystem
remount operations for issues.

Requiring a sync on every remount that doesn't go read-only seems odd
to me, so removing it doesn't sound bad.  However I agree that a proper
audit of filesystems should be done, e.g.:

  patch 1:
  	move calls into the filesystems, explaining why filesystems not
	implementing ->remount_fs should be safe
  patch 2:
  	remove call from ext4, safe because of $FOO
  patch b:
	remove call from $fs, safe because of $BAR