NFSv4/pnfs: Allow layoutget to return EAGAIN for softerr mounts

If we're using the 'softerr' mount option, we may want to allow
layoutget to return EAGAIN to allow knfsd server threads to return a
JUKEBOX/DELAY error to the client instead of busy waiting.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6f64fe97e72f371f74010034a0b7f8e193fa0b86..734643b60c484980e1fd8ce1c55d81f8eedd499e 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9646,6 +9646,9 @@ nfs4_layoutget_handle_exception(struct rpc_task *task,
 
        nfs4_sequence_free_slot(&lgp->res.seq_res);
 
+       exception->state = NULL;
+       exception->stateid = NULL;
+
        switch (nfs4err) {
        case 0:
                goto out;
@@ -9741,7 +9744,8 @@ static const struct rpc_call_ops nfs4_layoutget_call_ops = {
 };
 
 struct pnfs_layout_segment *
-nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout)
+nfs4_proc_layoutget(struct nfs4_layoutget *lgp,
+                   struct nfs4_exception *exception)
 {
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
@@ -9761,13 +9765,10 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout)
                         RPC_TASK_MOVEABLE,
        };
        struct pnfs_layout_segment *lseg = NULL;
-       struct nfs4_exception exception = {
-               .inode = inode,
-               .timeout = *timeout,
-       };
        int status = 0;
 
        nfs4_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0, 0);
+       exception->retry = 0;
 
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
@@ -9778,11 +9779,12 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout)
                goto out;
 
        if (task->tk_status < 0) {
-               status = nfs4_layoutget_handle_exception(task, lgp, &exception);
-               *timeout = exception.timeout;
+               exception->retry = 1;
+               status = nfs4_layoutget_handle_exception(task, lgp, exception);
        } else if (lgp->res.layoutp->len == 0) {
+               exception->retry = 1;
                status = -EAGAIN;
-               *timeout = nfs4_update_delay(&exception.timeout);
+               nfs4_update_delay(&exception->timeout);
        } else
                lseg = pnfs_layout_process(lgp);
 out:

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 84343aefbbd64cdf241fcf4e677ba50e991d9109..21a365357629c7531aeb8ec128cba116d41dc7dd 100644 (file)
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1980,7 +1980,9 @@ pnfs_update_layout(struct inode *ino,
        struct pnfs_layout_segment *lseg = NULL;
        struct nfs4_layoutget *lgp;
        nfs4_stateid stateid;
-       long timeout = 0;
+       struct nfs4_exception exception = {
+               .inode = ino,
+       };
        unsigned long giveup = jiffies + (clp->cl_lease_time << 1);
        bool first;
 
@@ -2144,7 +2146,7 @@ lookup_again:
        lgp->lo = lo;
        pnfs_get_layout_hdr(lo);
 
-       lseg = nfs4_proc_layoutget(lgp, &timeout);
+       lseg = nfs4_proc_layoutget(lgp, &exception);
        trace_pnfs_update_layout(ino, pos, count, iomode, lo, lseg,
                                 PNFS_UPDATE_LAYOUT_SEND_LAYOUTGET);
        nfs_layoutget_end(lo);
@@ -2171,6 +2173,8 @@ lookup_again:
                        goto out_put_layout_hdr;
                }
                if (lseg) {
+                       if (!exception.retry)
+                               goto out_put_layout_hdr;
                        if (first)
                                pnfs_clear_first_layoutget(lo);
                        trace_pnfs_update_layout(ino, pos, count,

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index d886c8226d8fecac631cf85dcfad283a4c5681e3..db57a85500ee70f07347f8de647ddca341f4b1ac 100644 (file)
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -35,6 +35,7 @@
 #include <linux/nfs_page.h>
 #include <linux/workqueue.h>
 
+struct nfs4_exception;
 struct nfs4_opendata;
 
 enum {
@@ -245,7 +246,9 @@ extern size_t max_response_pages(struct nfs_server *server);
 extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
                                   struct pnfs_device *dev,
                                   const struct cred *cred);
-extern struct pnfs_layout_segment* nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout);
+extern struct pnfs_layout_segment *
+nfs4_proc_layoutget(struct nfs4_layoutget *lgp,
+                   struct nfs4_exception *exception);
 extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool sync);
 
 /* pnfs.c */

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 9d82d50ce0b12dc7063f021d4380582633ed419f..b664caea8b4e6704bc0b46e8388487999697b80b 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -739,6 +739,8 @@ int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
                                        &pgio);
                pgio.pg_error = 0;
                nfs_pageio_complete(&pgio);
+               if (err == -EAGAIN && mntflags & NFS_MOUNT_SOFTERR)
+                       break;
        } while (err < 0 && !nfs_error_is_fatal(err));
        nfs_io_completion_put(ioc);