On 05/21, Eric Biggers via Linux-f2fs-devel wrote:

On Fri, May 22, 2026 at 03:32:39AM +0000, Jaegeuk Kim wrote:

quoted

On 05/21, Theodore Tso wrote:

quoted

On Thu, May 21, 2026 at 01:51:08AM -0700, Christoph Hellwig wrote:

quoted

quoted

You haven't sent a proposal.  This is a reply to a reply to a reply of a
patch.  There's no justification for why f2fs is so special that it
needs this.  What the hell is going on?  You know this is not the way to
get code merged into Linux.

None of this got properly answers, and this broken interface now landed
in linux-next. IT is offloading a user.* xattr which is free-form
user data with semantics that are weird to say it very nicely.

All this was done against the advice in the mailing list discussion.

So let me get this straight.  This is a magic xattr interface which is
not even persisted in the file system, but instead sets a 32-bit
bitmask in the struct inode which disappears once the inode gets
flushed from the inode stack.  And it uses a generic xattr name,
"user.fadvise".

There's no way in *hell* any other file system is likely to adopt such
a broken interface, so why didn't you just use an ioctl to set this
magic f2fs-specific flag?

I went this route because Android heavily restricts ioctl() permissions
and we needed broader access for this to work within the framework.

It's straightforward (2 lines I think) to update Android's SELinux
policy to allow an ioctl in all domains.  So that doesn't seem like a
reason to not use an ioctl.  In fact this is actually a reason *to* use
an ioctl, as it shows that ioctls can be allowed/denied independently as
needed, whereas xattrs just use the file write permission.

Ok, that's also great news to me.

- Eric


_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel