* [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
@ 2012-10-03 7:15 Suresh Jayaraman
[not found] ` <506BE618.7050606-IBi9RG/b67k@public.gmane.org>
0 siblings, 1 reply; 6+ messages in thread
From: Suresh Jayaraman @ 2012-10-03 7:15 UTC (permalink / raw)
To: Steve French; +Cc: linux-cifs, Jeff Layton
kernel_sendmsg() is less likely to return -ENOSPC and it might be
a bug to do so. However, in the past there might have been cases
where a -ENOSPC was returned from a low level driver.
Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
is no longer returned. This -ENOSPC specific handling will be removed
once we are sure it is no longer returned.
Also, avoid setting -ENOSPC to -EAGAIN while at it.
Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
---
fs/cifs/transport.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index d9b639b..afe000f 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -155,6 +155,10 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
n_vec - first_vec, total_len);
if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
+ /*
+ * Catch if a low level driver returns -ENOSPC.
+ */
+ WARN_ON_ONCE(rc == -ENOSPC);
i++;
/*
* If blocking send we try 3 times, since each can block
@@ -177,7 +181,6 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
cERROR(1, "sends on sock %p stuck for 15 seconds",
ssocket);
- rc = -EAGAIN;
break;
}
msleep(1 << i);
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
[not found] ` <506BE618.7050606-IBi9RG/b67k@public.gmane.org>
@ 2012-10-03 10:04 ` Jeff Layton
[not found] ` <20121003060410.07c30803-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
0 siblings, 1 reply; 6+ messages in thread
From: Jeff Layton @ 2012-10-03 10:04 UTC (permalink / raw)
To: Suresh Jayaraman; +Cc: Steve French, linux-cifs
On Wed, 03 Oct 2012 12:45:36 +0530
Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org> wrote:
> kernel_sendmsg() is less likely to return -ENOSPC and it might be
> a bug to do so. However, in the past there might have been cases
> where a -ENOSPC was returned from a low level driver.
>
> Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
> is no longer returned. This -ENOSPC specific handling will be removed
> once we are sure it is no longer returned.
>
> Also, avoid setting -ENOSPC to -EAGAIN while at it.
>
> Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
> ---
> fs/cifs/transport.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index d9b639b..afe000f 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -155,6 +155,10 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
> n_vec - first_vec, total_len);
> if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
> + /*
> + * Catch if a low level driver returns -ENOSPC.
> + */
> + WARN_ON_ONCE(rc == -ENOSPC);
> i++;
> /*
> * If blocking send we try 3 times, since each can block
> @@ -177,7 +181,6 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
> cERROR(1, "sends on sock %p stuck for 15 seconds",
> ssocket);
> - rc = -EAGAIN;
Do you really want to remove this reset? This will change the behavior
if the lower levels do indeed return -ENOSPC. That will now bubble back
up to the upper levels and it will likely abort the call instead of
retrying.
I think it would be best that we add the WARN_ON_ONCE but not change
anything else. If no one reports seeing that warning fire for 2 or 3
releases then we can safely remove the -ENOSPC handling. Maybe shoot
for that in 3.10 or so?
You may want to add a comment to remind us to revisit that for the 3.10
cycle.
> break;
> }
> msleep(1 << i);
--
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
[not found] ` <20121003060410.07c30803-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
@ 2012-10-03 15:43 ` Suresh Jayaraman
0 siblings, 0 replies; 6+ messages in thread
From: Suresh Jayaraman @ 2012-10-03 15:43 UTC (permalink / raw)
To: Jeff Layton; +Cc: Steve French, linux-cifs
On 10/03/2012 03:34 PM, Jeff Layton wrote:
> On Wed, 03 Oct 2012 12:45:36 +0530
> Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org> wrote:
>
>> kernel_sendmsg() is less likely to return -ENOSPC and it might be
>> a bug to do so. However, in the past there might have been cases
>> where a -ENOSPC was returned from a low level driver.
>>
>> Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
>> is no longer returned. This -ENOSPC specific handling will be removed
>> once we are sure it is no longer returned.
>>
>> Also, avoid setting -ENOSPC to -EAGAIN while at it.
>>
>> Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
>> ---
>> fs/cifs/transport.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
>> index d9b639b..afe000f 100644
>> --- a/fs/cifs/transport.c
>> +++ b/fs/cifs/transport.c
>> @@ -155,6 +155,10 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
>> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
>> n_vec - first_vec, total_len);
>> if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
>> + /*
>> + * Catch if a low level driver returns -ENOSPC.
>> + */
>> + WARN_ON_ONCE(rc == -ENOSPC);
>> i++;
>> /*
>> * If blocking send we try 3 times, since each can block
>> @@ -177,7 +181,6 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
>> if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
>> cERROR(1, "sends on sock %p stuck for 15 seconds",
>> ssocket);
>> - rc = -EAGAIN;
>
> Do you really want to remove this reset? This will change the behavior
> if the lower levels do indeed return -ENOSPC. That will now bubble back
> up to the upper levels and it will likely abort the call instead of
> retrying.
Yes, you are correct. I'll remove it.
>
> I think it would be best that we add the WARN_ON_ONCE but not change
> anything else. If no one reports seeing that warning fire for 2 or 3
> releases then we can safely remove the -ENOSPC handling. Maybe shoot
> for that in 3.10 or so?
>
> You may want to add a comment to remind us to revisit that for the 3.10
> cycle.
>
Sure, I'll add that when I respin.
Thanks
Suresh
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
@ 2012-10-03 15:57 Suresh Jayaraman
[not found] ` <506C6058.6060008-IBi9RG/b67k@public.gmane.org>
0 siblings, 1 reply; 6+ messages in thread
From: Suresh Jayaraman @ 2012-10-03 15:57 UTC (permalink / raw)
To: Steve French; +Cc: linux-cifs, Jeff Layton
kernel_sendmsg() is less likely to return -ENOSPC and it might be
a bug to do so. However, in the past there might have been cases
where a -ENOSPC was returned from a low level driver.
Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
is no longer returned. This -ENOSPC specific handling will be removed
once we are sure it is no longer returned.
Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
---
fs/cifs/transport.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index d9b639b..c613fca 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -155,6 +155,12 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
n_vec - first_vec, total_len);
if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
+ /*
+ * Catch if a low level driver returns -ENOSPC. This
+ * WARN_ON will be removed by 3.10 if no one reports
+ * seeing this.
+ */
+ WARN_ON_ONCE(rc == -ENOSPC);
i++;
/*
* If blocking send we try 3 times, since each can block
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
[not found] ` <506C6058.6060008-IBi9RG/b67k@public.gmane.org>
@ 2012-10-03 16:24 ` Jeff Layton
[not found] ` <20121003122417.51c52f31-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
0 siblings, 1 reply; 6+ messages in thread
From: Jeff Layton @ 2012-10-03 16:24 UTC (permalink / raw)
To: Suresh Jayaraman; +Cc: Steve French, linux-cifs
On Wed, 03 Oct 2012 21:27:12 +0530
Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org> wrote:
> kernel_sendmsg() is less likely to return -ENOSPC and it might be
> a bug to do so. However, in the past there might have been cases
> where a -ENOSPC was returned from a low level driver.
>
> Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
> is no longer returned. This -ENOSPC specific handling will be removed
> once we are sure it is no longer returned.
>
>
> Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
> ---
>
> fs/cifs/transport.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index d9b639b..c613fca 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -155,6 +155,12 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
> n_vec - first_vec, total_len);
> if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
> + /*
> + * Catch if a low level driver returns -ENOSPC. This
> + * WARN_ON will be removed by 3.10 if no one reports
> + * seeing this.
> + */
> + WARN_ON_ONCE(rc == -ENOSPC);
> i++;
> /*
> * If blocking send we try 3 times, since each can block
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
LGTM
Reviewed-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC
[not found] ` <20121003122417.51c52f31-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
@ 2012-10-03 19:16 ` Steve French
0 siblings, 0 replies; 6+ messages in thread
From: Steve French @ 2012-10-03 19:16 UTC (permalink / raw)
To: Jeff Layton; +Cc: Suresh Jayaraman, Steve French, linux-cifs
merged into cifs-2.6.git
On Wed, Oct 3, 2012 at 11:24 AM, Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
> On Wed, 03 Oct 2012 21:27:12 +0530
> Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org> wrote:
>
>> kernel_sendmsg() is less likely to return -ENOSPC and it might be
>> a bug to do so. However, in the past there might have been cases
>> where a -ENOSPC was returned from a low level driver.
>>
>> Add a WARN_ON_ONCE() to ensure that it is safe to assume that -ENOSPC
>> is no longer returned. This -ENOSPC specific handling will be removed
>> once we are sure it is no longer returned.
>>
>>
>> Cc: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Suresh Jayaraman <sjayaraman-IBi9RG/b67k@public.gmane.org>
>> ---
>>
>> fs/cifs/transport.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
>> index d9b639b..c613fca 100644
>> --- a/fs/cifs/transport.c
>> +++ b/fs/cifs/transport.c
>> @@ -155,6 +155,12 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
>> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
>> n_vec - first_vec, total_len);
>> if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
>> + /*
>> + * Catch if a low level driver returns -ENOSPC. This
>> + * WARN_ON will be removed by 3.10 if no one reports
>> + * seeing this.
>> + */
>> + WARN_ON_ONCE(rc == -ENOSPC);
>> i++;
>> /*
>> * If blocking send we try 3 times, since each can block
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
>> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> LGTM
>
> Reviewed-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
--
Thanks,
Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-10-03 19:16 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2012-10-03 7:15 [PATCH] cifs: WARN_ON_ONCE if kernel_sendmsg() returns -ENOSPC Suresh Jayaraman
[not found] ` <506BE618.7050606-IBi9RG/b67k@public.gmane.org>
2012-10-03 10:04 ` Jeff Layton
[not found] ` <20121003060410.07c30803-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2012-10-03 15:43 ` Suresh Jayaraman
-- strict thread matches above, loose matches on Subject: below --
2012-10-03 15:57 Suresh Jayaraman
[not found] ` <506C6058.6060008-IBi9RG/b67k@public.gmane.org>
2012-10-03 16:24 ` Jeff Layton
[not found] ` <20121003122417.51c52f31-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2012-10-03 19:16 ` Steve French
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