[PATCH 5.8 55/85] pNFS/flexfiles: Ensure we initialise the mirror bsizes correctly on read

[Greg Kroah-Hartman]

From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

[ Upstream commit ee15c7b53e52fb04583f734461244c4dcca828fa ]

While it is true that reading from an unmirrored source always uses
index 0, that is no longer true for mirrored sources when we fail over.

Fixes: 563c53e73b8b ("NFS: Fix flexfiles read failover")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/nfs/flexfilelayout/flexfilelayout.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 048272d60a165..f9348ed1bcdad 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -838,6 +838,7 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 	struct nfs4_ff_layout_mirror *mirror;
 	struct nfs4_pnfs_ds *ds;
 	int ds_idx;
+	u32 i;
 
 retry:
 	ff_layout_pg_check_layout(pgio, req);
@@ -864,14 +865,14 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
 		goto retry;
 	}
 
-	mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
+	for (i = 0; i < pgio->pg_mirror_count; i++) {
+		mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
+		pgm = &pgio->pg_mirrors[i];
+		pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
+	}
 
 	pgio->pg_mirror_idx = ds_idx;
 
-	/* read always uses only one mirror - idx 0 for pgio layer */
-	pgm = &pgio->pg_mirrors[0];
-	pgm->pg_bsize = mirror->mirror_ds->ds_versions[0].rsize;
-
 	if (NFS_SERVER(pgio->pg_inode)->flags &
 			(NFS_MOUNT_SOFT|NFS_MOUNT_SOFTERR))
 		pgio->pg_maxretrans = io_maxretrans;
-- 
2.25.1