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pNFS/flexfiles: When mirrored, retry failed reads by switching mirrors

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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>
This commit is contained in:
Trond Myklebust 2015-11-02 10:11:17 -05:00
parent a85240d254
commit 135444126a
1 changed files with 14 additions and 8 deletions
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22
fs/nfs/flexfilelayout/flexfilelayout.c
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@ -741,17 +741,17 @@ ff_layout_alloc_commit_info(struct pnfs_layout_segment *lseg,
}
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 @@ ff_layout_pg_init_read(struct nfs_pageio_descriptor *pgio,
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 @@ static int ff_layout_read_done_cb(struct rpc_task *task,
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 @@ static int ff_layout_read_done_cb(struct rpc_task *task,
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