* Re: [PATCH] nfsd: mark CONFIG_NFSD_FAULT_INJECTION as deprecated
2014-08-12 18:48 ` J. Bruce Fields
@ 2014-08-12 19:03 ` Jeff Layton
0 siblings, 0 replies; 3+ messages in thread
From: Jeff Layton @ 2014-08-12 19:03 UTC (permalink / raw)
To: J. Bruce Fields; +Cc: linux-nfs, Anna.Schumaker
On Tue, 12 Aug 2014 14:48:49 -0400
"J. Bruce Fields" <bfields@fieldses.org> wrote:
> On Wed, Aug 06, 2014 at 03:02:51PM -0400, Jeff Layton wrote:
> > The fault injection code is shaky at best. If you have a lot of stateful
> > objects, then you can end up overflowing the client's refcount. The code
> > is not widely used and is starting to become a maintenance burden mark
> > it DEPRECATED and document that we'll remove it in v3.19.
>
> I doubt anyone will notice a config text change on upgrade.
>
> If we think a deprecation warning's necessary then it would be more
> useful to put it in a printk() that fires the first time somebody uses
> one of these.
>
> --b.
>
> >
> > Signed-off-by: Jeff Layton <jlayton@primarydata.com>
> > ---
> > fs/nfsd/Kconfig | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
> > index f994e750e0d1..aad734c0b48a 100644
> > --- a/fs/nfsd/Kconfig
> > +++ b/fs/nfsd/Kconfig
> > @@ -98,11 +98,14 @@ config NFSD_V4_SECURITY_LABEL
> > For now we recommend "Y" only for developers and testers.
> >
> > config NFSD_FAULT_INJECTION
> > - bool "NFS server manual fault injection"
> > + bool "NFS server manual fault injection (DEPRECATED)"
> > depends on NFSD_V4 && DEBUG_KERNEL
> > help
> > This option enables support for manually injecting faults
> > into the NFS server. This is intended to be used for
> > testing error recovery on the NFS client.
> >
> > + This feature should not be enabled on production systems
> > + and will be removed in v3.19.
> > +
> > If unsure, say N.
> > --
> > 1.9.3
> >
Good point. Maybe something like this patch then? The printk is a
little sparse, but I'm not sure what else we should say there...
-----------------------[snip]--------------------------
[PATCH] nfsd: mark CONFIG_NFSD_FAULT_INJECTION as deprecated
The fault injection code is shaky at best. If you have a lot of stateful
objects, then you can end up overflowing the client's refcount. The code
is not widely used and is starting to become a maintenance burden. Mark
it DEPRECATED and document that we'll remove it in v3.19.
Also add a printk that will fire once whenever someone tries to use this
facility.
Cc: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
---
fs/nfsd/Kconfig | 5 ++++-
fs/nfsd/fault_inject.c | 16 ++++++++++++++++
2 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
index f994e750e0d1..aad734c0b48a 100644
--- a/fs/nfsd/Kconfig
+++ b/fs/nfsd/Kconfig
@@ -98,11 +98,14 @@ config NFSD_V4_SECURITY_LABEL
For now we recommend "Y" only for developers and testers.
config NFSD_FAULT_INJECTION
- bool "NFS server manual fault injection"
+ bool "NFS server manual fault injection (DEPRECATED)"
depends on NFSD_V4 && DEBUG_KERNEL
help
This option enables support for manually injecting faults
into the NFS server. This is intended to be used for
testing error recovery on the NFS client.
+ This feature should not be enabled on production systems
+ and will be removed in v3.19.
+
If unsure, say N.
diff --git a/fs/nfsd/fault_inject.c b/fs/nfsd/fault_inject.c
index c16bf5af6831..91874de13ae4 100644
--- a/fs/nfsd/fault_inject.c
+++ b/fs/nfsd/fault_inject.c
@@ -24,6 +24,18 @@ struct nfsd_fault_inject_op {
static struct dentry *debug_dir;
+static void
+warn_deprecated(void)
+{
+ static bool warned = false;
+
+ if (!warned) {
+ pr_notice("nfsd: the NFSD fault injection framework is "
+ "scheduled for removal in v3.19.\n");
+ warned = true;
+ }
+}
+
static ssize_t fault_inject_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
@@ -33,6 +45,8 @@ static ssize_t fault_inject_read(struct file *file, char __user *buf,
loff_t pos = *ppos;
struct nfsd_fault_inject_op *op = file_inode(file)->i_private;
+ warn_deprecated();
+
if (!pos)
val = op->get();
size = scnprintf(read_buf, sizeof(read_buf), "%llu\n", val);
@@ -51,6 +65,8 @@ static ssize_t fault_inject_write(struct file *file, const char __user *buf,
u64 val;
char *nl;
+ warn_deprecated();
+
if (copy_from_user(write_buf, buf, size))
return -EFAULT;
write_buf[size] = '\0';
--
1.9.3
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