Re: [PATCH 0/4] Fiemap, an extent mapping ioctl - round 2

[jim owens <jowens@hp.com>]

Dave Chinner wrote:

> xfs_bmap provides an atomic sync and mapping. If the
> FIEMAP_FLAG_SYNC is pushed down to the filesystem, then XFS
> and all other filesystems can provide that same atomicity if
> desired.

That is exactly what I was afraid of.

We are back to the "because XFS has it" argument.

But many other filesystems won't be able to provide
atomicity without normal operation performance being
reduced.  And I say we don't want fiemap to hurt
normal operation so fiemap should not impose even
an implied need for atomicity because programmers
will expect it and code for it.

If XFS users want atomic SYNC, they can use xfs_bmap,
or if XFS wants, it can always sync in its fiemap.

jim