From:	Peeter Joot <peeter@joot.com>
Subject: patch: new sysctl to remove hardcoded ELOOP limit
To:	torvalds@transmeta.com
Date:	Thu, 9 Apr 1998 01:46:27 -0400 (EDT)

Hi,

Currently 5 symlinks will be followed before ELOOP is returned.  Today 
I had a need for this to be 6 on my system.  Rather than just hacking the 
value and recompiling it I thought it made more sense to have a sysctl so 
this is adjustable.

I am appending a small patch against 2.1.94 for this.  I have tested this 
on 2.1.82, and merged the changes into 2.1.94 for the patch.  It hasn't
actually been tested on 2.1.94, but I can't imagine there are any problems -- 
it is a very simple modification.

Peeter
--
Peeter Joot
http://www.accessv.com/~peeter  peeter@accessv.com, Peeter_Joot@ca.ibm.com


diff --recursive -u linux.94/Documentation/sysctl/kernel.txt linux/Documentation/sysctl/kernel.txt
--- linux.94/Documentation/sysctl/kernel.txt	Thu Mar 19 18:04:30 1998
+++ linux/Documentation/sysctl/kernel.txt	Thu Apr  9 01:30:02 1998
@@ -34,6 +34,7 @@
 - real-root-dev               ==> Documentation/initrd.txt
 - reboot-cmd                  ==> SPARC specific
 - securelevel
+- symlinks-max
 - version
 
 ==============================================================
@@ -209,4 +210,11 @@
 ??? This seems to be a way to give an argument to the Sparc
 ROM/Flash boot loader. Maybe to tell it what to do after
 rebooting. ???
+
+==============================================================
+
+symlinks-max:
+
+Control how many symbolic links will be followed before ELOOP 
+is returned.  The default is 5.
 
diff --recursive -u linux.94/fs/namei.c linux/fs/namei.c
--- linux.94/fs/namei.c	Mon Jan 12 18:03:28 1998
+++ linux/fs/namei.c	Thu Apr  9 01:25:20 1998
@@ -80,6 +80,7 @@
 static char * quicklist = NULL;
 static int quickcount = 0;
 struct semaphore quicklock = MUTEX;
+int max_symlinks = 5;
 
 /* Tuning: increase locality by reusing same pages again...
  * if quicklist becomes too long on low memory machines, either a limit
@@ -303,7 +304,7 @@
 	struct inode * inode = dentry->d_inode;
 
 	if (inode && inode->i_op && inode->i_op->follow_link) {
-		if (current->link_count < 5) {
+		if (current->link_count < max_symlinks) {
 			struct dentry * result;
 
 			current->link_count++;
diff --recursive -u linux.94/include/linux/fs.h linux/include/linux/fs.h
--- linux.94/include/linux/fs.h	Wed Apr  8 21:15:10 1998
+++ linux/include/linux/fs.h	Thu Apr  9 01:25:20 1998
@@ -43,6 +43,7 @@
 
 /* And dynamically-tunable limits and defaults: */
 extern int max_inodes;
+extern int max_symlinks;
 extern int max_files, nr_files, nr_free_files;
 #define NR_INODE 4096	/* This should no longer be bigger than NR_FILE */
 #define NR_FILE  4096	/* this can well be larger on a larger system */
diff --recursive -u linux.94/include/linux/sysctl.h linux/include/linux/sysctl.h
--- linux.94/include/linux/sysctl.h	Wed Apr  1 19:19:57 1998
+++ linux/include/linux/sysctl.h	Thu Apr  9 01:27:35 1998
@@ -72,7 +72,8 @@
 	KERN_STATINODE,
 	KERN_DENTRY,		/* dentry statistics */
 	KERN_MODPROBE,
-	KERN_KMOD_UNLOAD_DELAY
+	KERN_KMOD_UNLOAD_DELAY,
+	KERN_MAXSYMLINKS	/* max levels of symbolic links */
 };
 
 
diff --recursive -u linux.94/kernel/sysctl.c linux/kernel/sysctl.c
--- linux.94/kernel/sysctl.c	Wed Apr  1 19:26:35 1998
+++ linux/kernel/sysctl.c	Thu Apr  9 01:26:44 1998
@@ -187,6 +187,8 @@
 	{KERN_NRFILE, "sg-big-buff", &sg_big_buff, sizeof (int),
 	 0444, NULL, &proc_dointvec},
 #endif
+       {KERN_MAXSYMLINKS, "symlinks-max", &max_symlinks, sizeof(int),
+        0644, NULL, &proc_dointvec},
 	{0}
 };
 

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