commit 4cacc965afc4fb03a465ffcc6cb3078aeadc3818

Author: Tomas Richter <krik3t@gmail.com>

Date:   Wed Feb 18 13:33:27 2009 -0500

    Exportfs and rpc.mountd optimalization

    There were some problems with exportfs and rpc.mountd for long export

    lists - see https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=76643

    I do optimalization as my bachelors thesis (Facuulty of informatics,

    Masaryk's university Brno, Czech Republic), under lead of Yenya

    Kasprzak.

    Both exportfs and rpc.mount build linked list of exports (shared

    functions in export.c). Every time they are inserting new export into

    list, they search for same export in list.

    I replaced linked list by hash table and functions export_add and

    export_lookup by functions hash_export_add and hash_export_lookup

    (export.c).

    Because some other functions required exportlist as linked list, hash

    table has some implementation modification im comparison with ordinary

    hash table. It also keeps exports in linked list  and has pointer to

    head of the list. So there's no need of implementation function

    <for_all_in_hash_table>.

    Signed-off-by: Tomas Richter <krik3t@gmail.com>

    Signed-off-by: Steve Dickson <steved@redhat.com>

diff -up nfs-utils-1.1.4/support/export/export.c.orig nfs-utils-1.1.4/support/export/export.c

--- nfs-utils-1.1.4/support/export/export.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/support/export/export.c	2009-02-18 19:42:13.000000000 -0500

@@ -19,7 +19,8 @@

 #include "nfslib.h"

 #include "exportfs.h"

-nfs_export	*exportlist[MCL_MAXTYPES] = { NULL, };

+exp_hash_table exportlist[MCL_MAXTYPES] = {{NULL, {{NULL,NULL}, }}, }; 

+static int export_hash(char *);

 static void	export_init(nfs_export *exp, nfs_client *clp,

 					struct exportent *nep);

@@ -125,22 +126,35 @@ export_dup(nfs_export *exp, struct hoste

 	return new;

 }

-

-void

+/*

+ * Add export entry to hash table

+ */

+void 

 export_add(nfs_export *exp)

 {

-	nfs_export	**epp;

-	int		type = exp->m_client->m_type;

-	int		slen = strlen(exp->m_export.e_path);

-

-	if (type < 0 || type >= MCL_MAXTYPES)

-		xlog(L_FATAL, "unknown client type in export_add");

-

-	epp = exportlist + type;

-	while (*epp && slen <= strlen((*epp)->m_export.e_path))

-		epp = &((*epp)->m_next);

-	exp->m_next = *epp;

-	*epp = exp;

+	exp_hash_table *p_tbl;

+	exp_hash_entry *p_hen;

+	nfs_export *p_next;

+

+	int type = exp->m_client->m_type;

+	int pos;

+

+	pos = export_hash(exp->m_export.e_path);

+	p_tbl = &(exportlist[type]); /* pointer to hash table */

+	p_hen = &(p_tbl->entries[pos]); /* pointer to hash table entry */

+

+	if (!(p_hen->p_first)) { /* hash table entry is empty */ 

+ 		p_hen->p_first = exp;

+ 		p_hen->p_last  = exp;

+

+ 		exp->m_next = p_tbl->p_head;

+ 		p_tbl->p_head = exp;

+	} else { /* hash table entry is NOT empty */

+		p_next = p_hen->p_last->m_next;

+		p_hen->p_last->m_next = exp;

+		exp->m_next = p_next;

+		p_hen->p_last = exp;

+	}

 }

 nfs_export *

@@ -150,7 +164,7 @@ export_find(struct hostent *hp, char *pa

 	int		i;

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			if (!export_check(exp, hp, path))

 				continue;

 			if (exp->m_client->m_type == MCL_FQDN)

@@ -169,7 +183,7 @@ export_allowed_internal (struct hostent 

 	int		i;

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			if (!exp->m_mayexport ||

 			    !export_check(exp, hp, path))

 				continue;

@@ -207,17 +221,30 @@ export_allowed(struct hostent *hp, char 

 	return NULL;

 }

+/*

+ * Search hash table for export entry. 

+ */  

 nfs_export *

-export_lookup(char *hname, char *path, int canonical)

+export_lookup(char *hname, char *path, int canonical) 

 {

-	nfs_client	*clp;

-	nfs_export	*exp;

+	nfs_client *clp;

+	nfs_export *exp;

+	exp_hash_entry *p_hen;

+

+	int pos;

-	if (!(clp = client_lookup(hname, canonical)))

+	clp = client_lookup(hname, canonical);

+	if(clp == NULL)

 		return NULL;

-	for (exp = exportlist[clp->m_type]; exp; exp = exp->m_next)

-		if (exp->m_client == clp && !strcmp(exp->m_export.e_path, path))

-			return exp;

+

+	pos = export_hash(path);

+	p_hen = &(exportlist[clp->m_type].entries[pos]); 

+	for(exp = p_hen->p_first; exp && (exp != p_hen->p_last->m_next); 

+  			exp = exp->m_next) {

+		if (exp->m_client == clp && !strcmp(exp->m_export.e_path, path)) {

+  			return exp;

+		}

+	}

 	return NULL;

 }

@@ -234,10 +261,10 @@ void

 export_freeall(void)

 {

 	nfs_export	*exp, *nxt;

-	int		i;

+	int		i, j;

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = nxt) {

+		for (exp = exportlist[i].p_head; exp; exp = nxt) {

 			nxt = exp->m_next;

 			client_release(exp->m_client);

 			if (exp->m_export.e_squids)

@@ -251,7 +278,40 @@ export_freeall(void)

 			xfree(exp->m_export.e_hostname);

 			xfree(exp);

 		}

-		exportlist[i] = NULL;

+      for(j = 0; j < HASH_TABLE_SIZE; j++) {

+        exportlist[i].entries[j].p_first = NULL;

+        exportlist[i].entries[j].p_last = NULL;

+      }

+      exportlist[i].p_head = NULL;

 	}

 	client_freeall();

 }

+

+/*

+ * Compute and returns integer from string. 

+ * Note: Its understood the smae integers can be same for 

+ *       different strings, but it should not matter.

+ */

+static unsigned int 

+strtoint(char *str)

+{

+	int i = 0;

+	unsigned int n = 0;

+

+	while ( str[i] != '\0') {

+		n+=((int)str[i])*i;

+		i++;

+	}

+	return n;

+}

+

+/*

+ * Hash function

+ */

+static int 

+export_hash(char *str)

+{

+	int num = strtoint(str);

+

+	return num % HASH_TABLE_SIZE;

+}

diff -up nfs-utils-1.1.4/support/export/xtab.c.orig nfs-utils-1.1.4/support/export/xtab.c

--- nfs-utils-1.1.4/support/export/xtab.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/support/export/xtab.c	2009-02-18 19:42:13.000000000 -0500

@@ -100,7 +100,7 @@ xtab_write(char *xtab, char *xtabtmp, in

 	setexportent(xtabtmp, "w");

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			if (is_export && !exp->m_xtabent)

 				continue;

 			if (!is_export && ! exp->m_exported)

diff -up nfs-utils-1.1.4/support/include/exportfs.h.orig nfs-utils-1.1.4/support/include/exportfs.h

--- nfs-utils-1.1.4/support/include/exportfs.h.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/support/include/exportfs.h	2009-02-18 19:42:13.000000000 -0500

@@ -52,8 +52,21 @@ typedef struct mexport {

 						 * matching one client */

 } nfs_export;

+#define HASH_TABLE_SIZE 1021

+

+typedef struct _exp_hash_entry {

+	nfs_export * p_first;

+  	nfs_export * p_last;

+} exp_hash_entry;

+

+typedef struct _exp_hash_table {

+	nfs_export * p_head;

+	exp_hash_entry entries[HASH_TABLE_SIZE];

+} exp_hash_table;

+

+extern exp_hash_table exportlist[MCL_MAXTYPES];

+

 extern nfs_client *		clientlist[MCL_MAXTYPES];

-extern nfs_export *		exportlist[MCL_MAXTYPES];

 nfs_client *			client_lookup(char *hname, int canonical);

 nfs_client *			client_find(struct hostent *);

@@ -69,7 +82,7 @@ struct hostent *		client_resolve(struct 

 int 				client_member(char *client, char *name);

 int				export_read(char *fname);

-void				export_add(nfs_export *);

+void			export_add(nfs_export *);

 void				export_reset(nfs_export *);

 nfs_export *			export_lookup(char *hname, char *path, int caconical);

 nfs_export *			export_find(struct hostent *, char *path);

diff -up nfs-utils-1.1.4/support/misc/tcpwrapper.c.orig nfs-utils-1.1.4/support/misc/tcpwrapper.c

--- nfs-utils-1.1.4/support/misc/tcpwrapper.c.orig	2009-02-17 16:45:04.000000000 -0500

+++ nfs-utils-1.1.4/support/misc/tcpwrapper.c	2009-02-18 19:42:13.000000000 -0500

@@ -91,7 +91,7 @@ inline unsigned int strtoint(char *str)

 	return n;

 }

-inline int hashint(unsigned int num)

+static inline int hashint(unsigned int num)

 {

 	return num % HASH_TABLE_SIZE;

 }

diff -up nfs-utils-1.1.4/utils/exportfs/exportfs.c.orig nfs-utils-1.1.4/utils/exportfs/exportfs.c

--- nfs-utils-1.1.4/utils/exportfs/exportfs.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/utils/exportfs/exportfs.c	2009-02-18 19:42:13.000000000 -0500

@@ -111,7 +111,6 @@ main(int argc, char **argv)

 			return 0;

 		}

 	}

-

 	if (f_export && ! f_ignore)

 		export_read(_PATH_EXPORTS);

 	if (f_export) {

@@ -193,10 +192,10 @@ exports_update(int verbose)

 {

 	nfs_export 	*exp;

-	for (exp = exportlist[MCL_FQDN]; exp; exp=exp->m_next) {

+	for (exp = exportlist[MCL_FQDN].p_head; exp; exp=exp->m_next) {

 		exports_update_one(exp, verbose);

 	}

-	for (exp = exportlist[MCL_GSS]; exp; exp=exp->m_next) {

+	for (exp = exportlist[MCL_GSS].p_head; exp; exp=exp->m_next) {

 		exports_update_one(exp, verbose);

 	}

 }

@@ -212,7 +211,7 @@ export_all(int verbose)

 	int		i;

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			if (verbose)

 				printf("exporting %s:%s\n",

 				       exp->m_client->m_hostname, 

@@ -308,7 +307,7 @@ unexportfs(char *arg, int verbose)

 		}

 	}

-	for (exp = exportlist[htype]; exp; exp = exp->m_next) {

+	for (exp = exportlist[htype].p_head; exp; exp = exp->m_next) {

 		if (path && strcmp(path, exp->m_export.e_path))

 			continue;

 		if (htype != exp->m_client->m_type)

@@ -453,7 +452,7 @@ dump(int verbose)

 	char		*hname, c;

 	for (htype = 0; htype < MCL_MAXTYPES; htype++) {

-		for (exp = exportlist[htype]; exp; exp = exp->m_next) {

+		for (exp = exportlist[htype].p_head; exp; exp = exp->m_next) {

 			ep = &exp->m_export;

 			if (!exp->m_xtabent)

 			    continue; /* neilb */

diff -up nfs-utils-1.1.4/utils/mountd/auth.c.orig nfs-utils-1.1.4/utils/mountd/auth.c

--- nfs-utils-1.1.4/utils/mountd/auth.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/utils/mountd/auth.c	2009-02-18 19:42:13.000000000 -0500

@@ -142,7 +142,7 @@ auth_authenticate_internal(char *what, s

 		exp = NULL;

 		for (i = 0; !exp && i < MCL_MAXTYPES; i++) 

-			for (exp = exportlist[i]; exp; exp = exp->m_next) {

+			for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 				if (strcmp(path, exp->m_export.e_path))

 					continue;

 				if (!use_ipaddr && !client_member(my_client.m_hostname, exp->m_client->m_hostname))

diff -up nfs-utils-1.1.4/utils/mountd/cache.c.orig nfs-utils-1.1.4/utils/mountd/cache.c

--- nfs-utils-1.1.4/utils/mountd/cache.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/utils/mountd/cache.c	2009-02-18 19:42:13.000000000 -0500

@@ -394,7 +394,7 @@ void nfsd_fh(FILE *f)

 	/* Now determine export point for this fsid/domain */

 	for (i=0 ; i < MCL_MAXTYPES; i++) {

 		nfs_export *next_exp;

-		for (exp = exportlist[i]; exp; exp = next_exp) {

+		for (exp = exportlist[i].p_head; exp; exp = next_exp) {

 			struct stat stb;

 			char u[16];

 			char *path;

@@ -654,7 +654,7 @@ void nfsd_export(FILE *f)

 	/* now find flags for this export point in this domain */

 	for (i=0 ; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			if (!use_ipaddr && !client_member(dom, exp->m_client->m_hostname))

 				continue;

 			if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {

diff -up nfs-utils-1.1.4/utils/mountd/mountd.c.orig nfs-utils-1.1.4/utils/mountd/mountd.c

--- nfs-utils-1.1.4/utils/mountd/mountd.c.orig	2008-10-17 10:20:09.000000000 -0400

+++ nfs-utils-1.1.4/utils/mountd/mountd.c	2009-02-18 19:42:13.000000000 -0500

@@ -521,7 +521,7 @@ get_exportlist(void)

 	elist = NULL;

 	for (i = 0; i < MCL_MAXTYPES; i++) {

-		for (exp = exportlist[i]; exp; exp = exp->m_next) {

+		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {

 			for (e = elist; e != NULL; e = e->ex_next) {

 				if (!strcmp(exp->m_export.e_path, e->ex_dir))

 					break;