Message-ID: <4E85D81F.3080108@netapp.com>
Date: Fri, 30 Sep 2011 10:54:23 -0400
From: Bryan Schumaker <bjschuma@netapp.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
CC: linux-nfs@vger.kernel.org
Subject: Re: [PATCH v3 1/3] NFSD: Added fault injection
References: <1317322765-19094-1-git-send-email-bjschuma@netapp.com> <20110930143508.GC19125@fieldses.org>
In-Reply-To: <20110930143508.GC19125@fieldses.org>
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Sender: linux-nfs-owner@vger.kernel.org
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On 09/30/2011 10:35 AM, J. Bruce Fields wrote:
> On Thu, Sep 29, 2011 at 02:59:23PM -0400, bjschuma@netapp.com wrote:
>> From: Bryan Schumaker <bjschuma@netapp.com>
>>
>> Fault injection on the NFS server makes it easier to test the client's
>> state manager and recovery threads.  Simulating errors on the server is
>> easier than finding the right conditions that cause them naturally.
> 
> You also might look at the unlock_ip interface that Wendy Cheng added a
> few years ago. The fact that it doesn't remove nfsv4 state is really a
> bug, it should be blowing away any relevant v4 clients as the same time.
> 
> (Though note the IP in question is a server IP, not a client IP.)

I'll take a look.  Thanks for the warning that it looks for a server IP, but would passing the client IP be more useful?

> 
> Is this the forget_n_clients scenario really a useful one to test?
> I'd've thought that the client would need to deal with the entire client
> diseappearing (due to network partition, for example), but not normally
> individual open owners.

It might not be a normal case, but it still could be interesting to see how the client recovers.

I was mostly looking at what state the server tracks and deleting what I could find.
> 
> --b.
> 
>> This patch uses debugfs to add a simple framework for fault injection to
>> the server.  This framework is a config option, and can be enabled
>> through CONFIG_NFSD_FAULT_INJECTION.  Assuming you have debugfs mounted
>> to /sys/debug, a set of files will be created in /sys/debug/nfsd/.
>> Writing to any of these files will cause the corresponding action and
>> write a log entry to dmesg.
>>
>> Changes in v3:
>> - Code cleanup and better use of generic functions
>> - Allow the user to input the number of state objects to delete
>> - Remove "forget_everything()" since forgetting a client is basically
>>   the same thing
>>
>> Changes in v2:
>> - Replaced "forget all state owners" with "forget all open owners"
>> - Include fs/nfsd/fault_inject.c in the patch
>>
>> Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
>> ---
>>  fs/nfsd/Kconfig        |   10 ++++
>>  fs/nfsd/Makefile       |    3 +-
>>  fs/nfsd/fault_inject.c |  102 ++++++++++++++++++++++++++++++++++++++++++
>>  fs/nfsd/nfs4state.c    |  115 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  fs/nfsd/nfsctl.c       |    6 +++
>>  fs/nfsd/nfsd.h         |   12 +++++
>>  6 files changed, 247 insertions(+), 1 deletions(-)
>>  create mode 100644 fs/nfsd/fault_inject.c
>>
>> diff --git a/fs/nfsd/Kconfig b/fs/nfsd/Kconfig
>> index 10e6366..52fdd1c 100644
>> --- a/fs/nfsd/Kconfig
>> +++ b/fs/nfsd/Kconfig
>> @@ -80,3 +80,13 @@ config NFSD_V4
>>  	  available from http://linux-nfs.org/.
>>  
>>  	  If unsure, say N.
>> +
>> +config NFSD_FAULT_INJECTION
>> +	bool "NFS server manual fault injection"
>> +	depends on NFSD_V4 && DEBUG_KERNEL
>> +	help
>> +	  This option enables support for manually injectiong faults
>> +	  into the NFS server.  This is intended to be used for
>> +	  testing error recovery on the NFS client.
>> +
>> +	  If unsure, say N.
>> diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
>> index 9b118ee..69eae75 100644
>> --- a/fs/nfsd/Makefile
>> +++ b/fs/nfsd/Makefile
>> @@ -5,7 +5,8 @@
>>  obj-$(CONFIG_NFSD)	+= nfsd.o
>>  
>>  nfsd-y 			:= nfssvc.o nfsctl.o nfsproc.o nfsfh.o vfs.o \
>> -			   export.o auth.o lockd.o nfscache.o nfsxdr.o stats.o
>> +			   export.o auth.o lockd.o nfscache.o nfsxdr.o stats.o \
>> +			   fault_inject.o
>>  nfsd-$(CONFIG_NFSD_V2_ACL) += nfs2acl.o
>>  nfsd-$(CONFIG_NFSD_V3)	+= nfs3proc.o nfs3xdr.o
>>  nfsd-$(CONFIG_NFSD_V3_ACL) += nfs3acl.o
>> diff --git a/fs/nfsd/fault_inject.c b/fs/nfsd/fault_inject.c
>> new file mode 100644
>> index 0000000..2139883
>> --- /dev/null
>> +++ b/fs/nfsd/fault_inject.c
>> @@ -0,0 +1,102 @@
>> +#ifdef CONFIG_NFSD_FAULT_INJECTION
>> +
>> +#include <linux/types.h>
>> +#include <linux/fs.h>
>> +#include <linux/debugfs.h>
>> +#include <linux/module.h>
>> +
>> +#include "state.h"
>> +#include "nfsd.h"
>> +
>> +struct nfsd_fault_inject_op {
>> +	char *action;
>> +	char *item;
>> +	char *file;
>> +	int file_data;
>> +	void (*func)(u64);
>> +};
>> +
>> +#define INJECTION_OP(op_action, op_item, op_func)	\
>> +{							\
>> +	.action = op_action,				\
>> +	.item   = op_item,				\
>> +	.file   = op_action"_"op_item,			\
>> +	.func   = op_func,				\
>> +}
>> +
>> +static struct nfsd_fault_inject_op inject_ops[] = {
>> +	INJECTION_OP("forget", "clients",     nfsd_forget_clients),
>> +	INJECTION_OP("forget", "locks",       nfsd_forget_locks),
>> +	INJECTION_OP("forget", "openowners",  nfsd_forget_openowners),
>> +	INJECTION_OP("forget", "delegations", nfsd_forget_delegations),
>> +	INJECTION_OP("recall", "delegations", nfsd_recall_delegations),
>> +};
>> +
>> +static long int NUM_INJECT_OPS = sizeof(inject_ops) / sizeof(struct nfsd_fault_inject_op);
>> +static struct dentry *debug_dir;
>> +
>> +static int nfsd_inject_set(void *data, u64 val)
>> +{
>> +	int i;
>> +	struct nfsd_fault_inject_op *op;
>> +
>> +	for (i = 0; i < NUM_INJECT_OPS; i++) {
>> +		op = &inject_ops[i];
>> +		if (&op->file_data == data) {
>> +			if (val == 0) {
>> +				printk(KERN_INFO "NFSD: Server %sing all %s",
>> +				op->action, op->item);
>> +			} else {
>> +				printk(KERN_INFO "NFSD: Server %sing at most %llu %s",
>> +				op->action, val, op->item);
>> +			}
>> +			op->func(val);
>> +		}
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int nfsd_inject_get(void *data, u64 *val)
>> +{
>> +	return 0;
>> +}
>> +
>> +DEFINE_SIMPLE_ATTRIBUTE(fops_nfsd, nfsd_inject_get, nfsd_inject_set, "%llu\n");
>> +
>> +void nfsd_fault_inject_cleanup(void)
>> +{
>> +	debugfs_remove_recursive(debug_dir);
>> +}
>> +
>> +int nfsd_fault_inject_init(void)
>> +{
>> +	unsigned int i;
>> +	struct nfsd_fault_inject_op *op;
>> +	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
>> +
>> +	debug_dir = debugfs_create_dir("nfsd", NULL);
>> +	if (!debug_dir)
>> +		goto fail;
>> +
>> +	for (i = 0; i < NUM_INJECT_OPS; i++) {
>> +		op = &inject_ops[i];
>> +		debugfs_create_file(op->file, mode, debug_dir, &op->file_data, &fops_nfsd);
>> +	}
>> +	return 0;
>> +
>> +fail:
>> +	nfsd_fault_inject_cleanup();
>> +	return -ENOMEM;
>> +}
>> +
>> +#else /* CONFIG_NFSD_FAULT_INJECTION */
>> +
>> +inline void nfsd_fault_inject_cleanup(void)
>> +{}
>> +
>> +inline int nfsd_fault_inject_init(void)
>> +{
>> +	return 0;
>> +}
>> +
>> +#endif /* CONFIG_NFSD_FAULT_INJECTION */
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 05f4c69..64fa6b0 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -4358,6 +4358,121 @@ nfs4_check_open_reclaim(clientid_t *clid)
>>  	return nfs4_find_reclaim_client(clid) ? nfs_ok : nfserr_reclaim_bad;
>>  }
>>  
>> +#ifdef CONFIG_NFSD_FAULT_INJECTION
>> +
>> +void nfsd_forget_clients(u64 num)
>> +{
>> +	struct nfs4_client *clp, *next;
>> +	int count = 0;
>> +
>> +	nfs4_lock_state();
>> +	list_for_each_entry_safe(clp, next, &client_lru, cl_lru) {
>> +		nfsd4_remove_clid_dir(clp);
>> +		expire_client(clp);
>> +		if (++count == num)
>> +			break;
>> +	}
>> +	nfs4_unlock_state();
>> +
>> +	printk(KERN_INFO "NFSD: Forgot %d clients", count);
>> +}
>> +
>> +static void release_lockowner_sop(struct nfs4_stateowner *sop)
>> +{
>> +	release_lockowner(lockowner(sop));
>> +}
>> +
>> +static void release_openowner_sop(struct nfs4_stateowner *sop)
>> +{
>> +	release_openowner(openowner(sop));
>> +}
>> +
>> +static int nfsd_release_n_owners(u64 num,
>> +				struct list_head hashtbl[],
>> +				unsigned int hashtbl_size,
>> +				void (*release_sop)(struct nfs4_stateowner *))
>> +{
>> +	int i, count = 0;
>> +	struct nfs4_stateowner *sop, *next;
>> +
>> +	for (i = 0; i < hashtbl_size; i++) {
>> +		list_for_each_entry_safe(sop, next, &hashtbl[i], so_strhash) {
>> +			release_sop(sop);
>> +			if (++count == num)
>> +				return count;
>> +		}
>> +	}
>> +	return count;
>> +}
>> +
>> +void nfsd_forget_locks(u64 num)
>> +{
>> +	int count;
>> +
>> +	nfs4_lock_state();
>> +	count = nfsd_release_n_owners(num, lock_ownerstr_hashtbl,
>> +				     LOCK_HASH_SIZE, release_lockowner_sop);
>> +	nfs4_unlock_state();
>> +
>> +	printk(KERN_INFO "NFSD: Forgot %d locks", count);
>> +}
>> +
>> +void nfsd_forget_openowners(u64 num)
>> +{
>> +	int count;
>> +
>> +	nfs4_lock_state();
>> +	count = nfsd_release_n_owners(num, open_ownerstr_hashtbl,
>> +				     OPEN_OWNER_HASH_SIZE, release_openowner_sop);
>> +	nfs4_unlock_state();
>> +
>> +	printk(KERN_INFO "NFSD: Forgot %d open owners", count);
>> +}
>> +
>> +int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *))
>> +{
>> +	int i, count = 0;
>> +	struct nfs4_file *fp;
>> +	struct nfs4_delegation *dp, *next;
>> +
>> +	for (i = 0; i < FILE_HASH_SIZE; i++) {
>> +		list_for_each_entry(fp, &file_hashtbl[i], fi_hash) {
>> +			list_for_each_entry_safe(dp, next, &fp->fi_delegations, dl_perfile) {
>> +				deleg_func(dp);
>> +				if (++count == num)
>> +					return count;
>> +			}
>> +		}
>> +	}
>> +	return count;
>> +}
>> +
>> +void nfsd_forget_delegations(u64 num)
>> +{
>> +	unsigned int count;
>> +
>> +	nfs4_lock_state();
>> +	count = nfsd_process_n_delegations(num, unhash_delegation);
>> +	nfs4_unlock_state();
>> +
>> +	printk(KERN_INFO "NFSD: Forgot %d delegations", count);
>> +}
>> +
>> +void nfsd_recall_delegations(u64 num)
>> +{
>> +	unsigned int count;
>> +
>> +	nfs4_lock_state();
>> +	spin_lock(&recall_lock);
>> +	count = nfsd_process_n_delegations(num, nfsd_break_one_deleg);
>> +	spin_unlock(&recall_lock);
>> +	nfs4_unlock_state();
>> +
>> +	printk(KERN_INFO "NFSD: Recalled %d delegations", count);
>> +}
>> +
>> +#endif /* CONFIG_NFSD_FAULT_INJECTION */
>> +
>>  /* initialization to perform at module load time: */
>>  
>>  int
>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>> index db34a58..e2f1b5a 100644
>> --- a/fs/nfsd/nfsctl.c
>> +++ b/fs/nfsd/nfsctl.c
>> @@ -1130,6 +1130,9 @@ static int __init init_nfsd(void)
>>  	retval = nfs4_state_init(); /* nfs4 locking state */
>>  	if (retval)
>>  		return retval;
>> +	retval = nfsd_fault_inject_init(); /* nfsd fault injection controls */
>> +	if (retval)
>> +		goto out_cleanup_fault_injection;
>>  	nfsd_stat_init();	/* Statistics */
>>  	retval = nfsd_reply_cache_init();
>>  	if (retval)
>> @@ -1161,6 +1164,8 @@ out_free_cache:
>>  out_free_stat:
>>  	nfsd_stat_shutdown();
>>  	nfsd4_free_slabs();
>> +out_cleanup_fault_injection:
>> +	nfsd_fault_inject_cleanup();
>>  	return retval;
>>  }
>>  
>> @@ -1174,6 +1179,7 @@ static void __exit exit_nfsd(void)
>>  	nfsd_lockd_shutdown();
>>  	nfsd_idmap_shutdown();
>>  	nfsd4_free_slabs();
>> +	nfsd_fault_inject_cleanup();
>>  	unregister_filesystem(&nfsd_fs_type);
>>  }
>>  
>> diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
>> index 58134a2..3ea303d 100644
>> --- a/fs/nfsd/nfsd.h
>> +++ b/fs/nfsd/nfsd.h
>> @@ -105,11 +105,18 @@ static inline int nfsd_v4client(struct svc_rqst *rq)
>>  #ifdef CONFIG_NFSD_V4
>>  extern unsigned int max_delegations;
>>  int nfs4_state_init(void);
>> +int nfsd_fault_inject_init(void);
>> +void nfsd_fault_inject_cleanup(void);
>>  void nfsd4_free_slabs(void);
>>  int nfs4_state_start(void);
>>  void nfs4_state_shutdown(void);
>>  void nfs4_reset_lease(time_t leasetime);
>>  int nfs4_reset_recoverydir(char *recdir);
>> +void nfsd_forget_clients(u64);
>> +void nfsd_forget_locks(u64);
>> +void nfsd_forget_openowners(u64);
>> +void nfsd_forget_delegations(u64);
>> +void nfsd_recall_delegations(u64);
>>  #else
>>  static inline int nfs4_state_init(void) { return 0; }
>>  static inline void nfsd4_free_slabs(void) { }
>> @@ -117,6 +124,11 @@ static inline int nfs4_state_start(void) { return 0; }
>>  static inline void nfs4_state_shutdown(void) { }
>>  static inline void nfs4_reset_lease(time_t leasetime) { }
>>  static inline int nfs4_reset_recoverydir(char *recdir) { return 0; }
>> +static inline void nfsd_forget_clients(u64) {}
>> +static inline void nfsd_forget_locks(u64) {}
>> +static inline void nfsd_forget_openowners(u64) {}
>> +static inline void nfsd_forget_delegations(u64) {}
>> +static inline void nfsd_recall_delegations(u64) {}
>>  #endif
>>  
>>  /*
>> -- 
>> 1.7.6.4
>>