On 12/13/21 8:30 AM, Konstantin Belousov wrote:
On Mon, Dec 13, 2021 at 04:26:42PM +0000, Rick Macklem wrote:
Hi,
There are two problems with Allocate in the NFSv4.2 server in FreeBSD13:
1 - It uses the thread credentials instead of the ones for the RPC.
2 - It does not ensure that file changes are committed to stable storage.
These problems are fixed by commit f0c9847a6c47 in main, which added
ioflag and cred arguments to VOP_ALLOCATE().
I can think of 3 ways to fix Allocate in FreeBSD13:
1 - Apply a *hackish* patch like this:
+ savcred = p->td_ucred;
+ td->td_ucred = cred;
do {
olen = len;
error = VOP_ALLOCATE(vp, &off, &len);
if (error == 0 && len > 0 && olen > len)
maybe_yield();
} while (error == 0 && len > 0 && olen > len);
+ p->td_ucred = savcred;
if (error == 0 && len > 0)
error = NFSERR_IO;
+ if (error == 0)
+ error = VOP_FSYNC(vp, MNT_WAIT, p);
The worst part of it is temporarily setting td_ucred to cred.
2 - MFC'ng commit f0c9847a6c47. Normally changes to the
VOP/VFS are not MFC'd. However, in this case, it might be
ok to do so, since it is unlikely there is an out of source tree
file system with a custom VOP_ALLOCATE() method?
I do not see much wrong with #2, this is what I would do myself.
I also think this is fine.
--
John Baldwin
