r/o bind mounts: filesystem helpers for custom 'struct file's

[safe/jmp/linux-2.6] / mm / tiny-shmem.c

diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c
index c13a216..d436a9c 100644 (file)
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -12,7 +12,6 @@
 
 #include <linux/fs.h>
 #include <linux/init.h>
-#include <linux/devfs_fs_kernel.h>
 #include <linux/vfs.h>
 #include <linux/mount.h>
 #include <linux/file.h>
@@ -31,11 +30,11 @@ static struct vfsmount *shm_mnt;
 
 static int __init init_tmpfs(void)
 {
-       register_filesystem(&tmpfs_fs_type);
-#ifdef CONFIG_TMPFS
-       devfs_mk_dir("shm");
-#endif
+       BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
+
        shm_mnt = kern_mount(&tmpfs_fs_type);
+       BUG_ON(IS_ERR(shm_mnt));
+
        return 0;
 }
 module_init(init_tmpfs)
@@ -67,24 +66,25 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
        if (!dentry)
                goto put_memory;
 
-       error = -ENFILE;
-       file = get_empty_filp();
-       if (!file)
-               goto put_dentry;
-
        error = -ENOSPC;
        inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
        if (!inode)
-               goto close_file;
+               goto put_dentry;
 
        d_instantiate(dentry, inode);
-       inode->i_size = size;
+       error = -ENFILE;
+       file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+                       &ramfs_file_operations);
+       if (!file)
+               goto put_dentry;
+
        inode->i_nlink = 0;     /* It is unlinked */
-       file->f_vfsmnt = mntget(shm_mnt);
-       file->f_dentry = dentry;
-       file->f_mapping = inode->i_mapping;
-       file->f_op = &ramfs_file_operations;
-       file->f_mode = FMODE_WRITE | FMODE_READ;
+
+       /* notify everyone as to the change of file size */
+       error = do_truncate(dentry, size, 0, file);
+       if (error < 0)
+               goto close_file;
+
        return file;
 
 close_file:
@@ -120,3 +120,26 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
 {
        return 0;
 }
+
+#if 0
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       file_accessed(file);
+#ifndef CONFIG_MMU
+       return ramfs_nommu_mmap(file, vma);
+#else
+       return 0;
+#endif
+}
+#endif  /*  0  */
+
+#ifndef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+                                     unsigned long addr,
+                                     unsigned long len,
+                                     unsigned long pgoff,
+                                     unsigned long flags)
+{
+       return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif