pNFS/flexfiles: When mirrored, retry failed reads by switching mirrors
If the pNFS/flexfiles file is mirrored, and a read to one mirror fails,
then we should bump the mirror index, so that we retry to a different
mirror. Once we've iterated through all mirrors and all failed, we can
return the layout and issue a new LAYOUTGET.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index fbc5a56..7fc14b9 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -741,17 +741,17 @@
}
static struct nfs4_pnfs_ds *
-ff_layout_choose_best_ds_for_read(struct nfs_pageio_descriptor *pgio,
+ff_layout_choose_best_ds_for_read(struct pnfs_layout_segment *lseg,
+ int start_idx,
int *best_idx)
{
- struct nfs4_ff_layout_segment *fls;
+ struct nfs4_ff_layout_segment *fls = FF_LAYOUT_LSEG(lseg);
struct nfs4_pnfs_ds *ds;
int idx;
- fls = FF_LAYOUT_LSEG(pgio->pg_lseg);
/* mirrors are sorted by efficiency */
- for (idx = 0; idx < fls->mirror_array_cnt; idx++) {
- ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, idx, false);
+ for (idx = start_idx; idx < fls->mirror_array_cnt; idx++) {
+ ds = nfs4_ff_layout_prepare_ds(lseg, idx, false);
if (ds) {
*best_idx = idx;
return ds;
@@ -782,7 +782,7 @@
if (pgio->pg_lseg == NULL)
goto out_mds;
- ds = ff_layout_choose_best_ds_for_read(pgio, &ds_idx);
+ ds = ff_layout_choose_best_ds_for_read(pgio->pg_lseg, 0, &ds_idx);
if (!ds)
goto out_mds;
mirror = FF_LAYOUT_COMP(pgio->pg_lseg, ds_idx);
@@ -1171,6 +1171,10 @@
switch (err) {
case -NFS4ERR_RESET_TO_PNFS:
+ if (ff_layout_choose_best_ds_for_read(hdr->lseg,
+ hdr->pgio_mirror_idx + 1,
+ &hdr->pgio_mirror_idx))
+ goto out_eagain;
set_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,
&hdr->lseg->pls_layout->plh_flags);
pnfs_read_resend_pnfs(hdr);
@@ -1179,11 +1183,13 @@
ff_layout_reset_read(hdr);
return task->tk_status;
case -EAGAIN:
- rpc_restart_call_prepare(task);
- return -EAGAIN;
+ goto out_eagain;
}
return 0;
+out_eagain:
+ rpc_restart_call_prepare(task);
+ return -EAGAIN;
}
static bool