2 files changed, 31 insertions, 10 deletions

diff --git a/fs/afs/Kconfig b/fs/afs/Kconfig
index 5c4e61d3c772..8f975f25b486 100644
--- a/fs/afs/Kconfig
+++ b/fs/afs/Kconfig
@@ -2,6 +2,7 @@ config AFS_FS
         tristate "Andrew File System support (AFS) (EXPERIMENTAL)"
         depends on INET && EXPERIMENTAL
         select AF_RXRPC
+        select DNS_RESOLVER
         help
           If you say Y here, you will get an experimental Andrew File System
           driver. It currently only supports unsecured read-only AFS access.
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index e19c13f059ed..ffea35c63879 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/key.h>
 #include <linux/ctype.h>
+#include <linux/dns_resolver.h>
 #include <linux/sched.h>
 #include <keys/rxrpc-type.h>
 #include "internal.h"
@@ -36,6 +37,8 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
         struct key *key;
         size_t namelen;
         char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
+        char  *dvllist = NULL, *_vllist = NULL;
+        char  delimiter = ':';
         int ret;
 
         _enter("%s,%s", name, vllist);
@@ -43,8 +46,10 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
         BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
 
         namelen = strlen(name);
-        if (namelen > AFS_MAXCELLNAME)
+        if (namelen > AFS_MAXCELLNAME) {
+                _leave(" = -ENAMETOOLONG");
                 return ERR_PTR(-ENAMETOOLONG);
+        }
 
         /* allocate and initialise a cell record */
         cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
@@ -64,15 +69,31 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
         INIT_LIST_HEAD(&cell->vl_list);
         spin_lock_init(&cell->vl_lock);
 
+        /* if the ip address is invalid, try dns query */
+        if (!vllist || strlen(vllist) < 7) {
+                ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
+                if (ret < 0) {
+                        _leave(" = %d", ret);
+                        return ERR_PTR(ret);
+                }
+                _vllist = dvllist;
+
+                /* change the delimiter for user-space reply */
+                delimiter = ',';
+
+        } else {
+                _vllist = vllist;
+        }
+
         /* fill in the VL server list from the rest of the string */
         do {
                 unsigned a, b, c, d;
 
-                next = strchr(vllist, ':');
+                next = strchr(_vllist, delimiter);
                 if (next)
                         *next++ = 0;
 
-                if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
+                if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
                         goto bad_address;
 
                 if (a > 255 || b > 255 || c > 255 || d > 255)
@@ -81,7 +102,7 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
                 cell->vl_addrs[cell->vl_naddrs++].s_addr =
                         htonl((a << 24) | (b << 16) | (c << 8) | d);
 
-        } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next));
+        } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
 
         /* create a key to represent an anonymous user */
         memcpy(keyname, "afs@", 4);
@@ -110,6 +131,7 @@ bad_address:
         ret = -EINVAL;
 error:
         key_put(cell->anonymous_key);
+        kfree(dvllist);
         kfree(cell);
         _leave(" = %d", ret);
         return ERR_PTR(ret);
@@ -201,14 +223,12 @@ int afs_cell_init(char *rootcell)
         }
 
         cp = strchr(rootcell, ':');
-        if (!cp) {
-                printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
-                _leave(" = -EINVAL");
-                return -EINVAL;
-        }
+        if (!cp)
+                _debug("kAFS: no VL server IP addresses specified");
+        else
+                *cp++ = 0;
 
         /* allocate a cell record for the root cell */
-        *cp++ = 0;
         new_root = afs_cell_create(rootcell, cp);
         if (IS_ERR(new_root)) {
                 _leave(" = %ld", PTR_ERR(new_root));