[PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Steve Dickson]

A typo, introduced by commit f11ac8db, in the nfs_direct_write()
routine causes writes with O_DIRECT set to fail with a ENOMEM error.

Found-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>
---
 fs/nfs/direct.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 064a809..84d3c8b 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 	dreq->inode = inode;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
 	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
-	if (dreq->l_ctx != NULL)
+	if (dreq->l_ctx == NULL)
 		goto out_release;
 	if (!is_sync_kiocb(iocb))
 		dreq->iocb = iocb;
-- 
1.7.2.3

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Jeff Layton]

On Thu, 28 Oct 2010 08:17:54 -0400
Steve Dickson <steved@redhat.com> wrote:

> A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> 
> Found-by: Jeff Layton <jlayton@redhat.com>
> Signed-off-by: Steve Dickson <steved@redhat.com>
> ---
>  fs/nfs/direct.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index 064a809..84d3c8b 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
>  	dreq->inode = inode;
>  	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
>  	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
> -	if (dreq->l_ctx != NULL)
> +	if (dreq->l_ctx == NULL)
>  		goto out_release;
>  	if (!is_sync_kiocb(iocb))
>  		dreq->iocb = iocb;

Also, since get_lock_context holds references, this prevents the fs
from being unmounted. It looks like this bug is in 2.6.36 too, so this
may be suitable for stable series as well.

-- 
Jeff Layton <jlayton@redhat.com>

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Jeff Layton]

On Thu, 28 Oct 2010 08:34:35 -0400
Jeff Layton <jlayton@redhat.com> wrote:

> On Thu, 28 Oct 2010 08:17:54 -0400
> Steve Dickson <steved@redhat.com> wrote:
> 
> > A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> > routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> > 
> > Found-by: Jeff Layton <jlayton@redhat.com>
> > Signed-off-by: Steve Dickson <steved@redhat.com>
> > ---
> >  fs/nfs/direct.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> > index 064a809..84d3c8b 100644
> > --- a/fs/nfs/direct.c
> > +++ b/fs/nfs/direct.c
> > @@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
> >  	dreq->inode = inode;
> >  	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
> >  	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
> > -	if (dreq->l_ctx != NULL)
> > +	if (dreq->l_ctx == NULL)
> >  		goto out_release;
> >  	if (!is_sync_kiocb(iocb))
> >  		dreq->iocb = iocb;
> 
> Also, since get_lock_context holds references, this prevents the fs
> from being unmounted. It looks like this bug is in 2.6.36 too, so this
> may be suitable for stable series as well.
> 

Oh...and another thing I noticed too...

nfs_create_request doesn't check for a NULL return from
nfs_get_lock_context. If it ever does, it looks like that will likely
trickle down to an oops in encode_stateid.

It might be good to fix that as well. Maybe something like this
compile-tested-only patch?

--------------------[snip]---------------------

nfs: handle lock context allocation failures in nfs_create_request

nfs_get_lock_context can return NULL on an allocation failure.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 fs/nfs/pagelist.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 9194902..137b549 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -65,6 +65,13 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
 	if (req == NULL)
 		return ERR_PTR(-ENOMEM);
 
+	/* get lock context early so we can deal with alloc failures */
+	req->wb_lock_context = nfs_get_lock_context(ctx);
+	if (req->wb_lock_context == NULL) {
+		nfs_page_free(req);
+		return ERR_PTR(-ENOMEM);
+	}
+
 	/* Initialize the request struct. Initially, we assume a
 	 * long write-back delay. This will be adjusted in
 	 * update_nfs_request below if the region is not locked. */
@@ -79,7 +86,6 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
 	req->wb_pgbase	= offset;
 	req->wb_bytes   = count;
 	req->wb_context = get_nfs_open_context(ctx);
-	req->wb_lock_context = nfs_get_lock_context(ctx);
 	kref_init(&req->wb_kref);
 	return req;
 }
-- 
1.7.2.3

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Trond Myklebust]

On Thu, 2010-10-28 at 09:55 -0400, Jeff Layton wrote:
> On Thu, 28 Oct 2010 08:34:35 -0400
> Jeff Layton <jlayton@redhat.com> wrote:
> 
> > On Thu, 28 Oct 2010 08:17:54 -0400
> > Steve Dickson <steved@redhat.com> wrote:
> > 
> > > A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> > > routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> > > 
> > > Found-by: Jeff Layton <jlayton@redhat.com>
> > > Signed-off-by: Steve Dickson <steved@redhat.com>
> > > ---
> > >  fs/nfs/direct.c |    2 +-
> > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> > > index 064a809..84d3c8b 100644
> > > --- a/fs/nfs/direct.c
> > > +++ b/fs/nfs/direct.c
> > > @@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
> > >  	dreq->inode = inode;
> > >  	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
> > >  	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
> > > -	if (dreq->l_ctx != NULL)
> > > +	if (dreq->l_ctx == NULL)
> > >  		goto out_release;
> > >  	if (!is_sync_kiocb(iocb))
> > >  		dreq->iocb = iocb;
> > 
> > Also, since get_lock_context holds references, this prevents the fs
> > from being unmounted. It looks like this bug is in 2.6.36 too, so this
> > may be suitable for stable series as well.
> > 
> 
> Oh...and another thing I noticed too...
> 
> nfs_create_request doesn't check for a NULL return from
> nfs_get_lock_context. If it ever does, it looks like that will likely
> trickle down to an oops in encode_stateid.
> 
> It might be good to fix that as well. Maybe something like this
> compile-tested-only patch?
> 
> --------------------[snip]---------------------
> 
> nfs: handle lock context allocation failures in nfs_create_request
> 
> nfs_get_lock_context can return NULL on an allocation failure.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/nfs/pagelist.c |    8 +++++++-
>  1 files changed, 7 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 9194902..137b549 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -65,6 +65,13 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
>  	if (req == NULL)
>  		return ERR_PTR(-ENOMEM);
>  
> +	/* get lock context early so we can deal with alloc failures */
> +	req->wb_lock_context = nfs_get_lock_context(ctx);
> +	if (req->wb_lock_context == NULL) {
> +		nfs_page_free(req);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
>  	/* Initialize the request struct. Initially, we assume a
>  	 * long write-back delay. This will be adjusted in
>  	 * update_nfs_request below if the region is not locked. */
> @@ -79,7 +86,6 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
>  	req->wb_pgbase	= offset;
>  	req->wb_bytes   = count;
>  	req->wb_context = get_nfs_open_context(ctx);
> -	req->wb_lock_context = nfs_get_lock_context(ctx);
>  	kref_init(&req->wb_kref);
>  	return req;
>  }

Yup. That looks as if it should be required...

Trond

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Jeff Layton]

On Thu, 28 Oct 2010 10:03:23 -0400
Trond Myklebust <Trond.Myklebust@netapp.com> wrote:

> On Thu, 2010-10-28 at 09:55 -0400, Jeff Layton wrote:
> > On Thu, 28 Oct 2010 08:34:35 -0400
> > Jeff Layton <jlayton@redhat.com> wrote:
> > 
> > > On Thu, 28 Oct 2010 08:17:54 -0400
> > > Steve Dickson <steved@redhat.com> wrote:
> > > 
> > > > A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> > > > routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> > > > 
> > > > Found-by: Jeff Layton <jlayton@redhat.com>
> > > > Signed-off-by: Steve Dickson <steved@redhat.com>
> > > > ---
> > > >  fs/nfs/direct.c |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > 
> > > > diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> > > > index 064a809..84d3c8b 100644
> > > > --- a/fs/nfs/direct.c
> > > > +++ b/fs/nfs/direct.c
> > > > @@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
> > > >  	dreq->inode = inode;
> > > >  	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
> > > >  	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
> > > > -	if (dreq->l_ctx != NULL)
> > > > +	if (dreq->l_ctx == NULL)
> > > >  		goto out_release;
> > > >  	if (!is_sync_kiocb(iocb))
> > > >  		dreq->iocb = iocb;
> > > 
> > > Also, since get_lock_context holds references, this prevents the fs
> > > from being unmounted. It looks like this bug is in 2.6.36 too, so this
> > > may be suitable for stable series as well.
> > > 
> > 
> > Oh...and another thing I noticed too...
> > 
> > nfs_create_request doesn't check for a NULL return from
> > nfs_get_lock_context. If it ever does, it looks like that will likely
> > trickle down to an oops in encode_stateid.
> > 
> > It might be good to fix that as well. Maybe something like this
> > compile-tested-only patch?
> > 
> > --------------------[snip]---------------------
> > 
> > nfs: handle lock context allocation failures in nfs_create_request
> > 
> > nfs_get_lock_context can return NULL on an allocation failure.
> > 
> > Signed-off-by: Jeff Layton <jlayton@redhat.com>
> > ---
> >  fs/nfs/pagelist.c |    8 +++++++-
> >  1 files changed, 7 insertions(+), 1 deletions(-)
> > 
> > diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> > index 9194902..137b549 100644
> > --- a/fs/nfs/pagelist.c
> > +++ b/fs/nfs/pagelist.c
> > @@ -65,6 +65,13 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
> >  	if (req == NULL)
> >  		return ERR_PTR(-ENOMEM);
> >  
> > +	/* get lock context early so we can deal with alloc failures */
> > +	req->wb_lock_context = nfs_get_lock_context(ctx);
> > +	if (req->wb_lock_context == NULL) {
> > +		nfs_page_free(req);
> > +		return ERR_PTR(-ENOMEM);
> > +	}
> > +
> >  	/* Initialize the request struct. Initially, we assume a
> >  	 * long write-back delay. This will be adjusted in
> >  	 * update_nfs_request below if the region is not locked. */
> > @@ -79,7 +86,6 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
> >  	req->wb_pgbase	= offset;
> >  	req->wb_bytes   = count;
> >  	req->wb_context = get_nfs_open_context(ctx);
> > -	req->wb_lock_context = nfs_get_lock_context(ctx);
> >  	kref_init(&req->wb_kref);
> >  	return req;
> >  }
> 
> Yup. That looks as if it should be required...
> 

Actually...Steve noticed this yesterday. I'll resend as an "official"
patch separate from this thread...

-- 
Jeff Layton <jlayton@redhat.com>

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Christoph Hellwig]

On Thu, Oct 28, 2010 at 08:17:54AM -0400, Steve Dickson wrote:
> A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> routine causes writes with O_DIRECT set to fail with a ENOMEM error.

I guess someone should run xfstests on nfs more regularly :)

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Trond Myklebust]

On Thu, 2010-10-28 at 08:38 -0400, Christoph Hellwig wrote:
> On Thu, Oct 28, 2010 at 08:17:54AM -0400, Steve Dickson wrote:
> > A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> > routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> 
> I guess someone should run xfstests on nfs more regularly :)

Sigh, yes... I should set up a VM to run all the test suites on a
regular basis...

Trond

Re: [PATCH] [bz 192] Fixed Regression in NFS Direct I/O path

[Trond Myklebust]

On Thu, 2010-10-28 at 08:17 -0400, Steve Dickson wrote:
> A typo, introduced by commit f11ac8db, in the nfs_direct_write()
> routine causes writes with O_DIRECT set to fail with a ENOMEM error.
> 
> Found-by: Jeff Layton <jlayton@redhat.com>
> Signed-off-by: Steve Dickson <steved@redhat.com>
> ---
>  fs/nfs/direct.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index 064a809..84d3c8b 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -873,7 +873,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
>  	dreq->inode = inode;
>  	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
>  	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
> -	if (dreq->l_ctx != NULL)
> +	if (dreq->l_ctx == NULL)
>  		goto out_release;
>  	if (!is_sync_kiocb(iocb))
>  		dreq->iocb = iocb;

Applied! Thanks!

Trond