new helper: ext2_image_size()

... implemented that way since the next commit will leave it
almost alone in ext2_fs.h - most of the file (including
struct ext2_super_block) is going to move to fs/ext2/ext2.h.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 5 deletions

diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 01f1306aa26e..6212586df29a 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -54,20 +54,19 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
 {
         const int size = 512;
         struct minix_super_block *minixsb;
-        struct ext2_super_block *ext2sb;
         struct romfs_super_block *romfsb;
         struct cramfs_super *cramfsb;
         struct squashfs_super_block *squashfsb;
         int nblocks = -1;
         unsigned char *buf;
         const char *compress_name;
+        unsigned long n;
 
         buf = kmalloc(size, GFP_KERNEL);
         if (!buf)
                 return -ENOMEM;
 
         minixsb = (struct minix_super_block *) buf;
-        ext2sb = (struct ext2_super_block *) buf;
         romfsb = (struct romfs_super_block *) buf;
         cramfsb = (struct cramfs_super *) buf;
         squashfsb = (struct squashfs_super_block *) buf;
@@ -150,12 +149,12 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
         }
 
         /* Try ext2 */
-        if (ext2sb->s_magic == cpu_to_le16(EXT2_SUPER_MAGIC)) {
+        n = ext2_image_size(buf);
+        if (n) {
                 printk(KERN_NOTICE
                        "RAMDISK: ext2 filesystem found at block %d\n",
                        start_block);
-                nblocks = le32_to_cpu(ext2sb->s_blocks_count) <<
-                        le32_to_cpu(ext2sb->s_log_block_size);
+                nblocks = n;
                 goto done;
         }