Re: NFS lockd patch proposal for user-level control of the grace period

[Juan Gomez <juang@us.ibm.com>]

[-- Attachment #1: Type: text/plain, Size: 2136 bytes --]





Christoph, Alan, Neil,

Attached you will find the patch with the sysctl implementation of my
previous patch to enable grace period control from user-land.
Please let me know if this looks good enough for inclusion in the kernel
distribution or whether I still need to do something else.
Note this piece is derived from net/sunrpc/sysctl.c, which by the way I
think has a problem with the READ/WRITE verifys which seem
 to be swicthed which I fixed in lockd version but not there, you may want
to take a look at net/sunrpc/sysctl.c and fix that although that's a minor
thing.

(See attached file: lockd-sysctl.patch)


Regards, Juan



|---------+---------------------------->
|         |           Alan Cox         |
|         |           <alan@lxorguk.   |
|         |           ukuu.org.uk>     |
|         |                            |
|         |           09/05/02 11:37 AM|
|         |                            |
|---------+---------------------------->
  >-----------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                             |
  |       To:       Juan Gomez/Almaden/IBM@IBMUS                                                                                |
  |       cc:                                                                                                                   |
  |       Subject:  Re: NFS lockd patch proposal for user-level control of the grace  period                                    |
  |                                                                                                                             |
  |                                                                                                                             |
  >-----------------------------------------------------------------------------------------------------------------------------|



I was waiting for a version that used the sysctl /proc/sys interface
instead. The concept of the interface is clearly fine



[-- Attachment #2: lockd-sysctl.patch --]
[-- Type: application/octet-stream, Size: 7598 bytes --]

diff -rcN linux-2.4.19/fs/lockd/Makefile linux-2.4.19-lockd-sysctl/fs/lockd/Makefile
*** linux-2.4.19/fs/lockd/Makefile	Fri Dec 29 14:07:23 2000
--- linux-2.4.19-lockd-sysctl/fs/lockd/Makefile	Fri Sep  6 19:09:02 2002
***************
*** 12,18 ****
  export-objs := lockd_syms.o
  
  obj-y    := clntlock.o clntproc.o host.o svc.o svclock.o svcshare.o \
! 	    svcproc.o svcsubs.o mon.o xdr.o lockd_syms.o
  
  obj-$(CONFIG_LOCKD_V4) += xdr4.o svc4proc.o
  
--- 12,18 ----
  export-objs := lockd_syms.o
  
  obj-y    := clntlock.o clntproc.o host.o svc.o svclock.o svcshare.o \
! 	    svcproc.o svcsubs.o mon.o xdr.o lockd_syms.o sysctl.o
  
  obj-$(CONFIG_LOCKD_V4) += xdr4.o svc4proc.o
  
diff -rcN linux-2.4.19/fs/lockd/svc.c linux-2.4.19-lockd-sysctl/fs/lockd/svc.c
*** linux-2.4.19/fs/lockd/svc.c	Sun Oct 21 10:32:33 2001
--- linux-2.4.19-lockd-sysctl/fs/lockd/svc.c	Fri Sep  6 21:44:32 2002
***************
*** 58,63 ****
--- 58,69 ----
  unsigned long			nlm_timeout = LOCKD_DFLT_TIMEO;
  unsigned long			nlm_udpport, nlm_tcpport;
  
+ /* Imports needed to support sysctl */
+ extern void             lockd_register_sysctl(void);
+ extern void             lockd_deregister_sysctl(void);
+ 
+ static unsigned long            grace_period_expire;
+ 
  static unsigned long set_grace_period(void)
  {
  	unsigned long grace_period;
***************
*** 72,82 ****
  	return grace_period + jiffies;
  }
  
! static inline void clear_grace_period(void)
  {
  	nlmsvc_grace_period = 0;
  }
  
  /*
   * This is the lockd kernel thread
   */
--- 78,97 ----
  	return grace_period + jiffies;
  }
  
! /* Public version of set_grace_period used from sysctl.c */
! inline void start_grace_period(void)
! {
! 
! 	grace_period_expire = set_grace_period();
! 
! }
! 
! inline void clear_grace_period(void)
  {
  	nlmsvc_grace_period = 0;
  }
  
+ 
  /*
   * This is the lockd kernel thread
   */
***************
*** 85,91 ****
  {
  	struct svc_serv	*serv = rqstp->rq_server;
  	int		err = 0;
- 	unsigned long grace_period_expire;
  
  	/* Lock module and set up kernel thread */
  	MOD_INC_USE_COUNT;
--- 100,105 ----
***************
*** 228,233 ****
--- 242,249 ----
  	if (nlmsvc_pid)
  		goto out;
  
+ 	lockd_register_sysctl();
+ 
  	/*
  	 * Sanity check: if there's no pid,
  	 * we should be the first user ...
***************
*** 291,296 ****
--- 307,314 ----
  			goto out;
  	} else
  		printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
+ 
+ 	lockd_deregister_sysctl();
  
  	if (!nlmsvc_pid) {
  		if (warned++ == 0)
diff -rcN linux-2.4.19/fs/lockd/sysctl.c linux-2.4.19-lockd-sysctl/fs/lockd/sysctl.c
*** linux-2.4.19/fs/lockd/sysctl.c	Wed Dec 31 16:00:00 1969
--- linux-2.4.19-lockd-sysctl/fs/lockd/sysctl.c	Fri Sep  6 19:08:18 2002
***************
*** 0 ****
--- 1,157 ----
+ 
+ #include <linux/types.h>
+ #include <linux/ctype.h>
+ #include <linux/sysctl.h>
+ #include <asm/errno.h>
+ #include <asm/uaccess.h>
+ #include <linux/kernel.h>
+ #include <linux/file.h>
+ 
+ static struct ctl_table_header  *lockd_table_header;
+ static ctl_table		lockd_table[];
+ 
+ /* Stuff imported from svc.c */
+ 
+ extern inline void start_grace_period(void);
+ extern inline void clear_grace_period(void);
+ extern int nlmsvc_grace_period;
+ 
+ 
+ /* Register with sysctl so we can export control of lockd to user-land
+  * via /proc/sys
+  */
+ 
+ void lockd_register_sysctl()
+ {
+ 
+   if (!lockd_table_header) {
+ 
+     printk("lockd_register_sysctl:=>register_sysctl_table()\n");
+     lockd_table_header = register_sysctl_table(lockd_table, 1);
+ 
+   }
+ 	
+ 
+ }/* void lockd_register_sysctl() */
+ 
+ 
+ 
+ 
+ /* De-register with sysctl so we do not have stale entries in 
+  * /proc/sys
+  */
+ 
+ void lockd_deregister_sysctl()
+ {
+ 
+ 	if (lockd_table_header) {
+ 	        printk("lockd_deregister_sysctl:=>register_sysctl_table()\n");
+ 		unregister_sysctl_table(lockd_table_header);
+ 		lockd_table_header = NULL;
+ 	}
+ 
+ }/* void lockd_deregister_sysctl() */
+ 
+ static int
+ proc_do_lockd_grace_period(ctl_table *table, 
+                            int write, 
+                            struct file *file,
+                            void *buffer, 
+                            size_t *lenp)
+ {
+ 	char		tmpbuf[20], *p, c;
+ 	unsigned int	value;
+ 	size_t		left, len;
+ 
+ 	printk("proc_do_lockd_grace_period: write=%d, lenp=%p, buffer=%p\n",
+ 	       write, lenp, buffer);
+ 	printk("proc_do_lockd_grace_period: len=%d\n", lenp ? *lenp : 0);
+ 
+ 	if ((file->f_pos && !write) || !*lenp) {
+ 		*lenp = 0;
+ 		return 0;
+ 	}
+ 
+ 	left = *lenp;
+ 
+ 	if (write) {
+ 
+           if (!access_ok(VERIFY_WRITE, buffer, left))
+             return -EFAULT;
+           p = (char *) buffer;
+           while (left && __get_user(c, p) >= 0 && isspace(c))
+             left--, p++;
+           if (!left)
+             goto done;
+           
+           if (left > sizeof(tmpbuf) - 1)
+             return -EINVAL;
+           copy_from_user(tmpbuf, p, left);
+           tmpbuf[left] = '\0';
+ 
+ 
+ 	  for (p = tmpbuf, value = 0; '0' <= *p && *p <= '9'; p++, left--)
+ 	    value = 10 * value + (*p - '0');
+ 	  if (*p && !isspace(*p))
+ 	    return -EINVAL;
+ 	  while (left && isspace(*p))
+ 	    left--, p++;
+ 
+           if (value == 0) {
+ 
+             clear_grace_period();
+ 
+           } else if(value == 1) {
+ 
+             start_grace_period();
+ 
+           } else {
+ 
+             return -EINVAL;
+ 
+           }
+           
+ 
+ 	} else {
+           /* Read Access */
+ 
+ 	  printk("proc_do_lockd_grace_period: reading...\n");
+ 
+           if (!access_ok(VERIFY_READ, buffer, left))
+             return -EFAULT;
+ 
+           len = sprintf(tmpbuf, "%d", nlmsvc_grace_period);
+           if (len > left)
+             len = left;
+           copy_to_user(buffer, tmpbuf, len);
+           if ((left -= len) > 0) {
+             put_user('\n', (char *)buffer + len);
+             left--;
+           }
+ 	}
+ 
+ done:
+ 	*lenp -= left;
+ 	file->f_pos += *lenp;
+ 	return 0;
+ 
+ }/*static int proc_do_lockd_sysctl() */
+ 
+ /* Define dir structure we want to export through /proc/fs */
+ 
+ #define DIRENTRY(nam1, nam2, child)	\
+ 	{CTL_##nam1, #nam2, NULL, 0, 0555, child }
+ #define LOCKD_FILE_ENTRY(nam1, nam2)	\
+ 	{LOCKD_CTL_##nam1##, "lockd_" #nam2, NULL, 0,\
+ 	 0644, NULL, &proc_do_lockd_grace_period}
+ 
+ static ctl_table		lockd_file_table[] = {
+ 	LOCKD_FILE_ENTRY(GRACE_PERIOD,  grace_period),
+ 	{0}
+ };
+ 
+ static ctl_table		lockd_table[] = {
+ 	DIRENTRY(LOCKD, lockd, lockd_file_table),
+ 	{0}
+ };
+ 
diff -rcN linux-2.4.19/include/linux/sysctl.h linux-2.4.19-lockd-sysctl/include/linux/sysctl.h
*** linux-2.4.19/include/linux/sysctl.h	Fri Aug  2 17:39:46 2002
--- linux-2.4.19-lockd-sysctl/include/linux/sysctl.h	Fri Sep  6 21:47:43 2002
***************
*** 63,69 ****
  	CTL_DEV=7,		/* Devices */
  	CTL_BUS=8,		/* Busses */
  	CTL_ABI=9,		/* Binary emulation */
! 	CTL_CPU=10		/* CPU stuff (speed scaling, etc) */
  };
  
  /* CTL_BUS names: */
--- 63,70 ----
  	CTL_DEV=7,		/* Devices */
  	CTL_BUS=8,		/* Busses */
  	CTL_ABI=9,		/* Binary emulation */
! 	CTL_CPU=10,		/* CPU stuff (speed scaling, etc) */
!         CTL_LOCKD=11,           /* Lockd info and control */
  };
  
  /* CTL_BUS names: */
***************
*** 627,632 ****
--- 628,641 ----
  	ABI_TRACE=5,		/* tracing flags */
  	ABI_FAKE_UTSNAME=6,	/* fake target utsname information */
  };
+ 
+ 
+ /* /proc/sys/lockd */
+ enum
+ {
+         LOCKD_CTL_GRACE_PERIOD=1,/* Enable user-level grace period control */
+ };
+ 
  
  #ifdef __KERNEL__