Re: [PATCH] always set a/c/mtime through ->setattr

[Miklos Szeredi <miklos@xxxxxxxxxx>]

> All major disk or in-memory filesystems except for XFS just pass down
> ATTR_*TIME requests to inode_setattr which is not more than just
> dirtying the inode.  NFS and CIFS set S_NOCMTIME so they're not affected
> by this at all.

I've checked, and relatively few filesystems set S_NOCMTIME:

 cifs, fuse, nfs

But there are quite a few others which don't call inode_setattr (which
means that the unchanged time optimization is lost), or which do
something possibly slow in their ->setattr():

 adfs, 9p, afs, coda, gfs2 ...

just to name a few at the start of the alphabet.

So it looks to me as this could cause some unintended performance
regressions in these filesystems.

Miklos