| Message ID | 506BE618.7050606@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 03 Oct 2012 12:45:36 +0530 Suresh Jayaraman <sjayaraman@suse.com> 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@redhat.com> > Signed-off-by: Suresh Jayaraman <sjayaraman@suse.com> > --- > 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);
On 10/03/2012 03:34 PM, Jeff Layton wrote: > On Wed, 03 Oct 2012 12:45:36 +0530 > Suresh Jayaraman <sjayaraman@suse.com> 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@redhat.com> >> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.com> >> --- >> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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);
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@redhat.com> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.com> --- fs/cifs/transport.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html