NFSv4/pNFS: Always allow update of a zero valued layout barrier

[ Upstream commit 45baadaad7bf9183651fb74f4ed1200da48505a5 ]

A zero value for the layout barrier indicates that it has been cleared
(since seqid '0' is an illegal value), so we should always allow it to
be updated.

Fixes: d29b468da4f9 ("pNFS/NFSv4: Improve rejection of out-of-order layouts")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 3ee607aa007bfeef8f1d83f099a8507616466dd9..6cc5ae51fd800c4c102b4ac712acf786d4029354 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -335,7 +335,7 @@ static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
 
 static void pnfs_barrier_update(struct pnfs_layout_hdr *lo, u32 newseq)
 {
-       if (pnfs_seqid_is_newer(newseq, lo->plh_barrier))
+       if (pnfs_seqid_is_newer(newseq, lo->plh_barrier) || !lo->plh_barrier)
                lo->plh_barrier = newseq;
 }