[v2,2/2] CIFS: Fix an issue with re-sending rdata when transport returning -EAGAIN
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Message ID 20190315075500.27747-2-longli@linuxonhyperv.com
State New
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Series
  • [v2,1/2] CIFS: Fix an issue with re-sending wdata when transport returning -EAGAIN
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Commit Message

Long Li March 15, 2019, 7:55 a.m. UTC
From: Long Li <longli@microsoft.com>

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 <longli@microsoft.com>
---
 fs/cifs/file.c | 71 +++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 41 insertions(+), 30 deletions(-)

Comments

Pavel Shilovsky March 16, 2019, 6:03 p.m. UTC | #1
пт, 15 мар. 2019 г. в 00:56, Long Li <longli@linuxonhyperv.com>:
>
> From: Long Li <longli@microsoft.com>
>
> 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 <longli@microsoft.com>
> ---
>  fs/cifs/file.c | 71 +++++++++++++++++++++++++++++++++-------------------------
>  1 file changed, 41 insertions(+), 30 deletions(-)
>
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 321df1d27422..9d90cc07e38b 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -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
>

Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

--
Best regards,
Pavel Shilovsky

Patch
diff mbox series

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 321df1d27422..9d90cc07e38b 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -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;
 }