Merge branch 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull root filesystem type handling updates from Al Viro:
 "Teach init/do_mounts.c to handle non-block filesystems, hopefully
  preventing even more special-cased kludges (such as root=/dev/nfs,
  etc)"

* 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: simplify get_filesystem_list / get_all_fs_names
  init: allow mounting arbitrary non-blockdevice filesystems as root
  init: split get_fs_names

diff --git a/fs/filesystems.c b/fs/filesystems.c
index 90b8d87..58b9067 100644 (file)
--- a/fs/filesystems.c
+++ b/fs/filesystems.c
@@ -209,21 +209,28 @@ SYSCALL_DEFINE3(sysfs, int, option, unsigned long, arg1, unsigned long, arg2)
 }
 #endif
 
-int __init get_filesystem_list(char *buf)
+int __init list_bdev_fs_names(char *buf, size_t size)
 {
-       int len = 0;
-       struct file_system_type * tmp;
+       struct file_system_type *p;
+       size_t len;
+       int count = 0;
 
        read_lock(&file_systems_lock);
-       tmp = file_systems;
-       while (tmp && len < PAGE_SIZE - 80) {
-               len += sprintf(buf+len, "%s\t%s\n",
-                       (tmp->fs_flags & FS_REQUIRES_DEV) ? "" : "nodev",
-                       tmp->name);
-               tmp = tmp->next;
+       for (p = file_systems; p; p = p->next) {
+               if (!(p->fs_flags & FS_REQUIRES_DEV))
+                       continue;
+               len = strlen(p->name) + 1;
+               if (len > size) {
+                       pr_warn("%s: truncating file system list\n", __func__);
+                       break;
+               }
+               memcpy(buf, p->name, len);
+               buf += len;
+               size -= len;
+               count++;
        }
        read_unlock(&file_systems_lock);
-       return len;
+       return count;
 }
 
 #ifdef CONFIG_PROC_FS

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 37ad9a7..29b3550 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3592,7 +3592,7 @@ int proc_nr_dentry(struct ctl_table *table, int write,
                  void *buffer, size_t *lenp, loff_t *ppos);
 int proc_nr_inodes(struct ctl_table *table, int write,
                   void *buffer, size_t *lenp, loff_t *ppos);
-int __init get_filesystem_list(char *buf);
+int __init list_bdev_fs_names(char *buf, size_t size);
 
 #define __FMODE_EXEC           ((__force int) FMODE_EXEC)
 #define __FMODE_NONOTIFY       ((__force int) FMODE_NONOTIFY)

diff --git a/init/do_mounts.c b/init/do_mounts.c
index b691d68..2ed30ff 100644 (file)
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -338,31 +338,22 @@ __setup("rootflags=", root_data_setup);
 __setup("rootfstype=", fs_names_setup);
 __setup("rootdelay=", root_delay_setup);
 
-static void __init get_fs_names(char *page)
+static int __init split_fs_names(char *page, char *names)
 {
-       char *s = page;
+       int count = 0;
+       char *p = page;
 
-       if (root_fs_names) {
-               strcpy(page, root_fs_names);
-               while (*s++) {
-                       if (s[-1] == ',')
-                               s[-1] = '\0';
-               }
-       } else {
-               int len = get_filesystem_list(page);
-               char *p, *next;
-
-               page[len] = '\0';
-               for (p = page-1; p; p = next) {
-                       next = strchr(++p, '\n');
-                       if (*p++ != '\t')
-                               continue;
-                       while ((*s++ = *p++) != '\n')
-                               ;
-                       s[-1] = '\0';
-               }
+       strcpy(p, root_fs_names);
+       while (*p++) {
+               if (p[-1] == ',')
+                       p[-1] = '\0';
        }
-       *s = '\0';
+       *p = '\0';
+
+       for (p = page; *p; p += strlen(p)+1)
+               count++;
+
+       return count;
 }
 
 static int __init do_mount_root(const char *name, const char *fs,
@@ -408,12 +399,16 @@ void __init mount_block_root(char *name, int flags)
        char *fs_names = page_address(page);
        char *p;
        char b[BDEVNAME_SIZE];
+       int num_fs, i;
 
        scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
                  MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
-       get_fs_names(fs_names);
+       if (root_fs_names)
+               num_fs = split_fs_names(fs_names, root_fs_names);
+       else
+               num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
 retry:
-       for (p = fs_names; *p; p += strlen(p)+1) {
+       for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
                int err = do_mount_root(name, p, flags, root_mount_data);
                switch (err) {
                        case 0:
@@ -442,7 +437,7 @@ retry:
        printk("List of all partitions:\n");
        printk_all_partitions();
        printk("No filesystem could mount root, tried: ");
-       for (p = fs_names; *p; p += strlen(p)+1)
+       for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
                printk(" %s", p);
        printk("\n");
        panic("VFS: Unable to mount root fs on %s", b);
@@ -526,6 +521,47 @@ static int __init mount_cifs_root(void)
 }
 #endif
 
+static bool __init fs_is_nodev(char *fstype)
+{
+       struct file_system_type *fs = get_fs_type(fstype);
+       bool ret = false;
+
+       if (fs) {
+               ret = !(fs->fs_flags & FS_REQUIRES_DEV);
+               put_filesystem(fs);
+       }
+
+       return ret;
+}
+
+static int __init mount_nodev_root(void)
+{
+       char *fs_names, *fstype;
+       int err = -EINVAL;
+       int num_fs, i;
+
+       fs_names = (void *)__get_free_page(GFP_KERNEL);
+       if (!fs_names)
+               return -EINVAL;
+       num_fs = split_fs_names(fs_names, root_fs_names);
+
+       for (i = 0, fstype = fs_names; i < num_fs;
+            i++, fstype += strlen(fstype) + 1) {
+               if (!fs_is_nodev(fstype))
+                       continue;
+               err = do_mount_root(root_device_name, fstype, root_mountflags,
+                                   root_mount_data);
+               if (!err)
+                       break;
+               if (err != -EACCES && err != -EINVAL)
+                       panic("VFS: Unable to mount root \"%s\" (%s), err=%d\n",
+                             root_device_name, fstype, err);
+       }
+
+       free_page((unsigned long)fs_names);
+       return err;
+}
+
 void __init mount_root(void)
 {
 #ifdef CONFIG_ROOT_NFS
@@ -542,6 +578,10 @@ void __init mount_root(void)
                return;
        }
 #endif
+       if (ROOT_DEV == 0 && root_device_name && root_fs_names) {
+               if (mount_nodev_root() == 0)
+                       return;
+       }
 #ifdef CONFIG_BLOCK
        {
                int err = create_dev("/dev/root", ROOT_DEV);