CIFS: Fix an issue with re-sending wdata when transport returning -EAGAIN

From: Long Li <[email protected]>

When sending a rdata, transport may return -EAGAIN. In this case we should re-obtain credits because the session may have been reconnected.

Change in v2: adjust_credits before re-sending

Signed-off-by Long Li <[email protected]>

---
 fs/cifs/file.c | 71 +++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 41 insertions(+), 30 deletions(-)

fs/cifs/file.c +41 -31

index 321df1d27422..9d90cc07e38b 100644
@@ -3347,44 +3347,55 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
        struct TCP_Server_Info *server =
                tlink_tcon(rdata->cfile->tlink)->ses->server;
 
-       /*
-        * Wait for credits to resend this rdata.
-        * Note: we are attempting to resend the whole rdata not in segments
-        */
        do {
-               rc = server->ops->wait_mtu_credits(server, rdata->bytes,
+               if (rdata->cfile->invalidHandle) {
+                       rc = cifs_reopen_file(rdata->cfile, true);
+                       if (rc == -EAGAIN)
+                               continue;
+                       else if (rc)
+                               break;
+               }
+
+               /*
+                * Wait for credits to resend this rdata.
+                * Note: we are attempting to resend the whole rdata not in
+                * segments
+                */
+               do {
+                       rc = server->ops->wait_mtu_credits(server, rdata->bytes,
                                                &rsize, &credits);
 
-               if (rc)
-                       goto out;
+                       if (rc)
+                               goto fail;
 
-               if (rsize < rdata->bytes) {
-                       add_credits_and_wake_if(server, &credits, 0);
-                       msleep(1000);
-               }
-       } while (rsize < rdata->bytes);
+                       if (rsize < rdata->bytes) {
+                               add_credits_and_wake_if(server, &credits, 0);
+                               msleep(1000);
+                       }
+               } while (rsize < rdata->bytes);
+               rdata->credits = credits;
 
-       rdata->credits = credits;
-       rc = -EAGAIN;
-       while (rc == -EAGAIN) {
-               rc = 0;
-               if (rdata->cfile->invalidHandle)
-                       rc = cifs_reopen_file(rdata->cfile, true);
-               if (!rc)
-                       rc = server->ops->async_readv(rdata);
-       }
+               rc = adjust_credits(server, &rdata->credits, rdata->bytes);
+               if (!rc) {
+                       if (rdata->cfile->invalidHandle)
+                               rc = -EAGAIN;
+                       else
+                               rc = server->ops->async_readv(rdata);
+               }
 
-       if (!rc) {
-               /* Add to aio pending list */
-               list_add_tail(&rdata->list, rdata_list);
-               return 0;
-       }
+               /* If the read was successfully sent, we are done */
+               if (!rc) {
+                       /* Add to aio pending list */
+                       list_add_tail(&rdata->list, rdata_list);
+                       return 0;
+               }
 
-       add_credits_and_wake_if(server, &rdata->credits, 0);
-out:
-       kref_put(&rdata->refcount,
-               cifs_uncached_readdata_release);
+               /* Roll back credits and retry if needed */
+               add_credits_and_wake_if(server, &rdata->credits, 0);
+       } while (rc == -EAGAIN);
 
+fail:
+       kref_put(&rdata->refcount, cifs_uncached_readdata_release);
        return rc;
 }
 
--

2.14.1

From: Long Li <[email protected]>

When sending a wdata, transport may return -EAGAIN. In this case we should re-obtain credits because the session may have been reconnected.

Change in v2: adjust_credits before re-sending

Signed-off-by Long Li <[email protected]>

---
 fs/cifs/file.c | 77 ++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 45 insertions(+), 32 deletions(-)

fs/cifs/file.c +45 -33

index 9b53f33137b3..321df1d27422 100644
@@ -2620,43 +2620,56 @@ cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
        struct TCP_Server_Info *server =
                tlink_tcon(wdata->cfile->tlink)->ses->server;
 
-       /*
-        * Wait for credits to resend this wdata.
-        * Note: we are attempting to resend the whole wdata not in segments
-        */
        do {
-               rc = server->ops->wait_mtu_credits(server, wdata->bytes, &wsize,
-                                                  &credits);
+               if (wdata->cfile->invalidHandle) {
+                       rc = cifs_reopen_file(wdata->cfile, false);
+                       if (rc == -EAGAIN)
+                               continue;
+                       else if (rc)
+                               break;
+               }
 
-               if (rc)
-                       goto out;
 
-               if (wsize < wdata->bytes) {
-                       add_credits_and_wake_if(server, &credits, 0);
-                       msleep(1000);
-               }
-       } while (wsize < wdata->bytes);
+               /*
+                * Wait for credits to resend this wdata.
+                * Note: we are attempting to resend the whole wdata not in
+                * segments
+                */
+               do {
+                       rc = server->ops->wait_mtu_credits(server, wdata->bytes,
+                                               &wsize, &credits);
+                       if (rc)
+                               goto fail;
+
+                       if (wsize < wdata->bytes) {
+                               add_credits_and_wake_if(server, &credits, 0);
+                               msleep(1000);
+                       }
+               } while (wsize < wdata->bytes);
+               wdata->credits = credits;
 
-       wdata->credits = credits;
-       rc = -EAGAIN;
-       while (rc == -EAGAIN) {
-               rc = 0;
-               if (wdata->cfile->invalidHandle)
-                       rc = cifs_reopen_file(wdata->cfile, false);
-               if (!rc)
-                       rc = server->ops->async_writev(wdata,
+               rc = adjust_credits(server, &wdata->credits, wdata->bytes);
+
+               if (!rc) {
+                       if (wdata->cfile->invalidHandle)
+                               rc = -EAGAIN;
+                       else
+                               rc = server->ops->async_writev(wdata,
                                        cifs_uncached_writedata_release);
-       }
+               }
 
-       if (!rc) {
-               list_add_tail(&wdata->list, wdata_list);
-               return 0;
-       }
+               /* If the write was successfully sent, we are done */
+               if (!rc) {
+                       list_add_tail(&wdata->list, wdata_list);
+                       return 0;
+               }
 
-       add_credits_and_wake_if(server, &wdata->credits, 0);
-out:
-       kref_put(&wdata->refcount, cifs_uncached_writedata_release);
+               /* Roll back credits and retry if needed */
+               add_credits_and_wake_if(server, &wdata->credits, 0);
+       } while (rc == -EAGAIN);
 
+fail:
+       kref_put(&wdata->refcount, cifs_uncached_writedata_release);
        return rc;
 }
 

@@ -2884,12 +2897,12 @@ static void collect_uncached_write_data(struct cifs_aio_ctx *ctx)
                                                wdata->bytes, &tmp_from,
                                                ctx->cfile, cifs_sb, &tmp_list,
                                                ctx);
+
+                                       kref_put(&wdata->refcount,
+                                               cifs_uncached_writedata_release);
                                }
 
                                list_splice(&tmp_list, &ctx->list);
-
-                               kref_put(&wdata->refcount,
-                                        cifs_uncached_writedata_release);
                                goto restart_loop;
                        }
                }
--

2.14.1