git: f419fd9ad817 - stable/12 - nfsclient: Fix the stripe unit size for a File Layout pNFS layout

[Rick Macklem]

The branch stable/12 has been updated by rmacklem:

URL: https://cgit.FreeBSD.org/src/commit/?id=f419fd9ad81707f831a48412ecbc5c958675d38c

commit f419fd9ad81707f831a48412ecbc5c958675d38c
Author:     Rick Macklem <rmacklem at FreeBSD.org>
AuthorDate: 2021-03-01 20:49:32 +0000
Commit:     Rick Macklem <rmacklem at FreeBSD.org>
CommitDate: 2021-03-15 19:51:26 +0000

    nfsclient: Fix the stripe unit size for a File Layout pNFS layout
    
    During a recent virtual NFSv4 testing event, a bug in the FreeBSD client
    was detected when doing a File Layout pNFS DS I/O operation.
    The size of the I/O operation was smaller than expected.
    The I/O size is specified as a stripe unit size in bits 6->31 of nflh_util
    in the layout.  I had misinterpreted RFC5661 and had shifted the value
    right by 6 bits. The correct interpretation is to use the value as
    presented (it is always an exact multiple of 64), clearing bits 0->5.
    This patch fixes this.
    
    Without the patch, I/O through the DSs work, but the I/O size is 1/64th
    of what is optimal.
    
    (cherry picked from commit 94f2e42f5e0b78a7a4684d4a4eb62ea470a57eb1)
---
 sys/fs/nfsclient/nfs_clrpcops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/fs/nfsclient/nfs_clrpcops.c b/sys/fs/nfsclient/nfs_clrpcops.c
index e1c5c7ff3316..cab5ec4005ba 100644
--- a/sys/fs/nfsclient/nfs_clrpcops.c
+++ b/sys/fs/nfsclient/nfs_clrpcops.c
@@ -5911,7 +5911,7 @@ nfscl_doflayoutio(vnode_t vp, struct uio *uiop, int *iomode, int *must_commit,
 
 	np = VTONFS(vp);
 	rel_off = off - flp->nfsfl_patoff;
-	stripe_unit_size = (flp->nfsfl_util >> 6) & 0x3ffffff;
+	stripe_unit_size = flp->nfsfl_util & NFSFLAYUTIL_STRIPE_MASK;
 	stripe_pos = (rel_off / stripe_unit_size + flp->nfsfl_stripe1) %
 	    dp->nfsdi_stripecnt;
 	transfer = stripe_unit_size - (rel_off % stripe_unit_size);