Just sorting through random stuff sitting in my kernel repository:
This is for your amusement only (not to be applied): I wanted to produce
traces showing the effect of the reply cache on the server's response to
replays. After applying these patches:
echo 1 >/proc/fs/nfsd/drop_rename
will drop the next NFSv3 rename seen by the server, and
echo 1 >/proc/fs/nfsd/disable_reply_cache
will turn off the reply cache.
--b.
>From e28638551f1b28e09b87498bdb9b2c2401a14a68 Mon Sep 17 00:00:00 2001
From: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Date: Fri, 14 Nov 2008 09:28:21 -0500
Subject: [PATCH] nfsd: allow dropping renames
Drop the first NFSv3 rename seen; just to produce a packet trace
demonstrating dropped request and replay.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
---
fs/nfsd/nfsctl.c | 17 +++++++++++++++++
fs/nfsd/nfssvc.c | 7 +++++++
2 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index e3f9783..3bc957c 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -63,6 +63,7 @@ enum {
NFSD_Versions,
NFSD_Ports,
NFSD_MaxBlkSize,
+ NFSD_DropRename,
/*
* The below MUST come last. Otherwise we leave a hole in nfsd_files[]
* with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
@@ -89,6 +90,7 @@ static ssize_t write_pool_threads(struct file *file, char *buf, size_t size);
static ssize_t write_versions(struct file *file, char *buf, size_t size);
static ssize_t write_ports(struct file *file, char *buf, size_t size);
static ssize_t write_maxblksize(struct file *file, char *buf, size_t size);
+static ssize_t write_droprename(struct file *file, char *buf, size_t size);
#ifdef CONFIG_NFSD_V4
static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
@@ -113,6 +115,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Versions] = write_versions,
[NFSD_Ports] = write_ports,
[NFSD_MaxBlkSize] = write_maxblksize,
+ [NFSD_DropRename] = write_droprename,
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = write_leasetime,
[NFSD_RecoveryDir] = write_recoverydir,
@@ -727,6 +730,19 @@ static ssize_t write_maxblksize(struct file *file, char *buf, size_t size)
return sprintf(buf, "%d\n", nfsd_max_blksize);
}
+int drop_rename_count;
+
+static ssize_t write_droprename(struct file *file, char *buf, size_t size)
+{
+ char *mesg = buf;
+ if (size > 0) {
+ int rv = get_int(&mesg, &drop_rename_count);
+ if (rv)
+ return rv;
+ }
+ return sprintf(buf, "%d\n", drop_rename_count);
+}
+
#ifdef CONFIG_NFSD_V4
extern time_t nfs4_leasetime(void);
@@ -826,6 +842,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
[NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},
+ [NFSD_DropRename] = {"drop_rename", &transaction_ops, S_IWUSR|S_IRUGO},
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 07e4f5d..49f24a8 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -503,6 +503,8 @@ static __be32 map_new_errors(u32 vers, __be32 nfserr)
return nfserr;
}
+extern int drop_rename_count;
+
int
nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
{
@@ -572,5 +574,10 @@ nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
/* Store reply in cache. */
nfsd_cache_update(rqstp, proc->pc_cachetype, statp + 1);
+ if (drop_rename_count &&
+ rqstp->rq_vers == 3 && rqstp->rq_proc == NFS3PROC_RENAME) {
+ drop_rename_count--;
+ return 0;
+ }
return 1;
}
--
1.5.5.rc1
>From 25978a41777434d3f15014f614e4fbaca9c28978 Mon Sep 17 00:00:00 2001
From: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Date: Fri, 14 Nov 2008 10:44:42 -0500
Subject: [PATCH] nfsd: allow disabling reply cache
For demonstration purposes.
---
fs/nfsd/nfscache.c | 2 +-
fs/nfsd/nfsctl.c | 17 +++++++++++++++++
2 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 5bfc2ac..d4bece7 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -33,7 +33,7 @@
static struct hlist_head * hash_list;
static struct list_head lru_head;
-static int cache_disabled = 1;
+extern int cache_disabled;
static int nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 3bc957c..63b4f36 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -64,6 +64,7 @@ enum {
NFSD_Ports,
NFSD_MaxBlkSize,
NFSD_DropRename,
+ NFSD_DisableReplyCache,
/*
* The below MUST come last. Otherwise we leave a hole in nfsd_files[]
* with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
@@ -91,6 +92,7 @@ static ssize_t write_versions(struct file *file, char *buf, size_t size);
static ssize_t write_ports(struct file *file, char *buf, size_t size);
static ssize_t write_maxblksize(struct file *file, char *buf, size_t size);
static ssize_t write_droprename(struct file *file, char *buf, size_t size);
+static ssize_t write_disable_reply_cache(struct file *file, char *buf, size_t size);
#ifdef CONFIG_NFSD_V4
static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
@@ -116,6 +118,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Ports] = write_ports,
[NFSD_MaxBlkSize] = write_maxblksize,
[NFSD_DropRename] = write_droprename,
+ [NFSD_DisableReplyCache] = write_disable_reply_cache,
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = write_leasetime,
[NFSD_RecoveryDir] = write_recoverydir,
@@ -743,6 +746,19 @@ static ssize_t write_droprename(struct file *file, char *buf, size_t size)
return sprintf(buf, "%d\n", drop_rename_count);
}
+int cache_disabled = 1;
+
+static ssize_t write_disable_reply_cache(struct file *file, char *buf, size_t size)
+{
+ char *mesg = buf;
+ if (size > 0) {
+ int rv = get_int(&mesg, &cache_disabled);
+ if (rv)
+ return rv;
+ }
+ return sprintf(buf, "%d\n", cache_disabled);
+}
+
#ifdef CONFIG_NFSD_V4
extern time_t nfs4_leasetime(void);
@@ -843,6 +859,7 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_Ports] = {"portlist", &transaction_ops, S_IWUSR|S_IRUGO},
[NFSD_MaxBlkSize] = {"max_block_size", &transaction_ops, S_IWUSR|S_IRUGO},
[NFSD_DropRename] = {"drop_rename", &transaction_ops, S_IWUSR|S_IRUGO},
+ [NFSD_DisableReplyCache] = {"disable_reply_cache", &transaction_ops, S_IWUSR|S_IRUGO},
#ifdef CONFIG_NFSD_V4
[NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
--
1.5.5.rc1
