pNFS/flexfiles: Fix an Oopsable condition when connection to the DS fails
If the attempt to connect to a DS fails inside ff_layout_pg_init_read or
ff_layout_pg_init_write, then we currently end up clearing the layout
segment carried by the struct nfs_pageio_descriptor, causing an Oops
when we later call into ff_layout_read_pagelist/ff_layout_write_pagelist.
The fix is to ensure we return the layout and then retry.
Fixes: 446ca2195303 ("pNFS/flexfiles: When initing reads or writes, we...")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index ee1c94c7..51b5136 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -806,11 +806,14 @@
{
struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
struct nfs4_pnfs_ds *ds;
+ bool fail_return = false;
int idx;
/* mirrors are sorted by efficiency */
for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
- ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
+ if (idx+1 == fls->mirror_array_cnt)
+ fail_return = true;
+ ds = nfs4_ff_layout_prepare_ds(lseg, idx, fail_return);
if (ds) {
*best_idx = idx;
return ds;
@@ -859,6 +862,7 @@
struct nfs4_pnfs_ds *ds;
int ds_idx;
+retry:
/* Use full layout for now */
if (!pgio->pg_lseg)
ff_layout_pg_get_read(pgio, req, false);
@@ -871,10 +875,13 @@
ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
if (!ds) {
- if (ff_layout_no_fallback_to_mds(pgio->pg_lseg))
- goto out_pnfs;
- else
+ if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
goto out_mds;
+ pnfs_put_lseg(pgio->pg_lseg);
+ pgio->pg_lseg = NULL;
+ /* Sleep for 1 second before retrying */
+ ssleep(1);
+ goto retry;
}
mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
@@ -890,12 +897,6 @@
pnfs_put_lseg(pgio->pg_lseg);
pgio->pg_lseg = NULL;
nfs_pageio_reset_read_mds(pgio);
- return;
-
-out_pnfs:
- pnfs_set_lo_fail(pgio->pg_lseg);
- pnfs_put_lseg(pgio->pg_lseg);
- pgio->pg_lseg = NULL;
}
static void
@@ -909,6 +910,7 @@
int i;
int status;
+retry:
if (!pgio->pg_lseg) {
pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
req->wb_context,
@@ -940,10 +942,13 @@
for (i = 0; i < pgio->pg_mirror_count; i++) {
ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
if (!ds) {
- if (ff_layout_no_fallback_to_mds(pgio->pg_lseg))
- goto out_pnfs;
- else
+ if (!ff_layout_no_fallback_to_mds(pgio->pg_lseg))
goto out_mds;
+ pnfs_put_lseg(pgio->pg_lseg);
+ pgio->pg_lseg = NULL;
+ /* Sleep for 1 second before retrying */
+ ssleep(1);
+ goto retry;
}
pgm = &pgio->pg_mirrors[i];
mirror = FF_LAYOUT_COMP(pgio->pg_lseg, i);
@@ -956,12 +961,6 @@
pnfs_put_lseg(pgio->pg_lseg);
pgio->pg_lseg = NULL;
nfs_pageio_reset_write_mds(pgio);
- return;
-
-out_pnfs:
- pnfs_set_lo_fail(pgio->pg_lseg);
- pnfs_put_lseg(pgio->pg_lseg);
- pgio->pg_lseg = NULL;
}
static unsigned int