NFSv4: Document the recover_lost_locks kernel parameter

Rename the new 'recover_locks' kernel parameter to 'recover_lost_locks' and change the default to 'false'. Document why in Documentation/kernel-parameters.txt Move the 'recover_lost_locks' kernel parameter to fs/nfs/super.c to make it easy to backport to kernels prior to 3.6.x, which don't have a separate NFSv4 module. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

NFSv4: Document the recover_lost_locks kernel parameter
Rename the new 'recover_locks' kernel parameter to 'recover_lost_locks' and change the default to 'false'. Document why in Documentation/kernel-parameters.txt Move the 'recover_lost_locks' kernel parameter to fs/nfs/super.c to make it easy to backport to kernels prior to 3.6.x, which don't have a separate NFSv4 module. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Trond Myklebust
1 parent ef1820f9be
Showing 4 changed files with 22 additions and 7 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
fs/nfs/nfs4_fs.h
fs/nfs/nfs4proc.c
fs/nfs/super.c
@@ -1847,6 +1847,18 @@
 			will be sent.
 			The default is to send the implementation identification
 			information.
+	
+	nfs.recover_lost_locks =
+			[NFSv4] Attempt to recover locks that were lost due
+			to a lease timeout on the server. Please note that
+			doing this risks data corruption, since there are
+			no guarantees that the file will remain unchanged
+			after the locks are lost.
+			If you want to enable the kernel legacy behaviour of
+			attempting to recover these locks, then set this
+			parameter to '1'.
+			The default parameter value of '0' causes the kernel
+			not to attempt recovery of lost locks.
  
 	nfsd.nfs4_disable_idmapping=
 			[NFSv4] When set to the default of '1', the NFSv4
@@ -372,6 +372,7 @@
 extern bool nfs4_disable_idmapping;
 extern unsigned short max_session_slots;
 extern unsigned short send_implementation_id;
+extern bool recover_lost_locks;
  
 #define NFS4_CLIENT_ID_UNIQ_LEN		(64)
 extern char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN];
@@ -5523,12 +5523,6 @@
 	return err;
 }
  
-bool recover_locks = true;
-module_param(recover_locks, bool, 0644);
-MODULE_PARM_DESC(recover_locks,
-		 "If the server reports that a lock might be lost, "
-		 "try to recovery it risking corruption.");
-
 static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request)
 {
 	struct nfs_server *server = NFS_SERVER(state->inode);
@@ -5540,7 +5534,7 @@
 	err = nfs4_set_lock_state(state, request);
 	if (err != 0)
 		return err;
-	if (!recover_locks) {
+	if (!recover_lost_locks) {
 		set_bit(NFS_LOCK_LOST, &request->fl_u.nfs4_fl.owner->ls_flags);
 		return 0;
 	}
@@ -2758,6 +2758,7 @@
 unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
 unsigned short send_implementation_id = 1;
 char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
+bool recover_lost_locks = false;
  
 EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
 EXPORT_SYMBOL_GPL(nfs_callback_tcpport);
@@ -2766,6 +2767,7 @@
 EXPORT_SYMBOL_GPL(max_session_slots);
 EXPORT_SYMBOL_GPL(send_implementation_id);
 EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
+EXPORT_SYMBOL_GPL(recover_lost_locks);
  
 #define NFS_CALLBACK_MAXPORTNR (65535U)
  
@@ -2802,6 +2804,12 @@
 MODULE_PARM_DESC(send_implementation_id,
 		"Send implementation ID with NFSv4.1 exchange_id");
 MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
+
+module_param(recover_lost_locks, bool, 0644);
+MODULE_PARM_DESC(recover_lost_locks,
+		 "If the server reports that a lock might be lost, "
+		 "try to recover it risking data corruption.");
+
  
 #endif /* CONFIG_NFS_V4 */
...	...	@@ -1847,6 +1847,18 @@
1847	1847	will be sent.
1848	1848	The default is to send the implementation identification
1849	1849	information.
	1850	+
	1851	+ nfs.recover_lost_locks =
	1852	+ [NFSv4] Attempt to recover locks that were lost due
	1853	+ to a lease timeout on the server. Please note that
	1854	+ doing this risks data corruption, since there are
	1855	+ no guarantees that the file will remain unchanged
	1856	+ after the locks are lost.
	1857	+ If you want to enable the kernel legacy behaviour of
	1858	+ attempting to recover these locks, then set this
	1859	+ parameter to '1'.
	1860	+ The default parameter value of '0' causes the kernel
	1861	+ not to attempt recovery of lost locks.
1850	1862
1851	1863	nfsd.nfs4_disable_idmapping=
1852	1864	[NFSv4] When set to the default of '1', the NFSv4
...	...	@@ -372,6 +372,7 @@
372	372	extern bool nfs4_disable_idmapping;
373	373	extern unsigned short max_session_slots;
374	374	extern unsigned short send_implementation_id;
	375	+extern bool recover_lost_locks;
375	376
376	377	#define NFS4_CLIENT_ID_UNIQ_LEN (64)
377	378	extern char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN];
...	...	@@ -5523,12 +5523,6 @@
5523	5523	return err;
5524	5524	}
5525	5525
5526		-bool recover_locks = true;
5527		-module_param(recover_locks, bool, 0644);
5528		-MODULE_PARM_DESC(recover_locks,
5529		- "If the server reports that a lock might be lost, "
5530		- "try to recovery it risking corruption.");
5531		-
5532	5526	static int nfs4_lock_expired(struct nfs4_state state, struct file_lock request)
5533	5527	{
5534	5528	struct nfs_server *server = NFS_SERVER(state->inode);
...	...	@@ -5540,7 +5534,7 @@
5540	5534	err = nfs4_set_lock_state(state, request);
5541	5535	if (err != 0)
5542	5536	return err;
5543		- if (!recover_locks) {
	5537	+ if (!recover_lost_locks) {
5544	5538	set_bit(NFS_LOCK_LOST, &request->fl_u.nfs4_fl.owner->ls_flags);
5545	5539	return 0;
5546	5540	}
...	...	@@ -2758,6 +2758,7 @@
2758	2758	unsigned short max_session_slots = NFS4_DEF_SLOT_TABLE_SIZE;
2759	2759	unsigned short send_implementation_id = 1;
2760	2760	char nfs4_client_id_uniquifier[NFS4_CLIENT_ID_UNIQ_LEN] = "";
	2761	+bool recover_lost_locks = false;
2761	2762
2762	2763	EXPORT_SYMBOL_GPL(nfs_callback_set_tcpport);
2763	2764	EXPORT_SYMBOL_GPL(nfs_callback_tcpport);
...	...	@@ -2766,6 +2767,7 @@
2766	2767	EXPORT_SYMBOL_GPL(max_session_slots);
2767	2768	EXPORT_SYMBOL_GPL(send_implementation_id);
2768	2769	EXPORT_SYMBOL_GPL(nfs4_client_id_uniquifier);
	2770	+EXPORT_SYMBOL_GPL(recover_lost_locks);
2769	2771
2770	2772	#define NFS_CALLBACK_MAXPORTNR (65535U)
2771	2773
...	...	@@ -2802,6 +2804,12 @@
2802	2804	MODULE_PARM_DESC(send_implementation_id,
2803	2805	"Send implementation ID with NFSv4.1 exchange_id");
2804	2806	MODULE_PARM_DESC(nfs4_unique_id, "nfs_client_id4 uniquifier string");
	2807	+
	2808	+module_param(recover_lost_locks, bool, 0644);
	2809	+MODULE_PARM_DESC(recover_lost_locks,
	2810	+ "If the server reports that a lock might be lost, "
	2811	+ "try to recover it risking data corruption.");
	2812	+
2805	2813
2806	2814	#endif /* CONFIG_NFS_V4 */