Greg KH wrote:
Now I just know I'm going to regret this somehow...
Anyway, here's yet-another-ramfs-based filesystem, ndevfs.
Here's your code against vanilla 2.6.12.
I ran it on an ARM machine, was able to successfully mount it and do an
'ls'. Not an exhaustive test, obviously.
Only errors I saw in the output were:
...
Freeing init memory: 100K
ndevfs: creating file 'vcs1' with major 7 and minor 1
ndevfs: creating file 'vcsa1' with major 7 and minor 129
ndevfs: creating file 'vcs1' with major 7 and minor 1
ndevfs_create failed with error -17
ndevfs: creating file 'vcsa1' with major 7 and minor 129
ndevfs_create failed with error -17
...
I don't know what vcs1 and vcsa1 are, not sure I really care... :^)
I moved your Kconfig diff; it was showing up in miscellaneous
filesystems, I put it in pseudo filesystems instead.
b.g.
--
Bill Gatliff
[email protected]
Professional embedded Linux training.
--- orig/drivers/base/class.c
+++ mod/drivers/base/class.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
+#include <linux/ndevfs.h>
#include "base.h"
#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
@@ -422,8 +423,10 @@
up(&parent->sem);
}
- if (MAJOR(class_dev->devt))
+ if (MAJOR(class_dev->devt)) {
class_device_create_file(class_dev, &class_device_attr_dev);
+ ndevfs_create(class_dev->class_id, class_dev->devt, 1);
+ }
class_device_add_attrs(class_dev);
if (class_dev->dev)
@@ -458,8 +461,10 @@
up(&parent->sem);
}
- if (class_dev->dev)
+ if (class_dev->dev) {
sysfs_remove_link(&class_dev->kobj, "device");
+ ndevfs_remove(class_dev->class_id);
+ }
class_device_remove_attrs(class_dev);
kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
--- orig/fs/Kconfig
+++ mod/fs/Kconfig
@@ -813,6 +813,12 @@
If you are not using a security module that requires using
extended attributes for file security labels, say N.
+config NDEV_FS
+ bool "Nano Device File System"
+ help
+ A proposed replacement for devfs. If you aren't sure,
+ say N.
+
config TMPFS
bool "Virtual memory file system support (former shm fs)"
help
--- orig/fs/Makefile
+++ mod/fs/Makefile
@@ -95,3 +95,4 @@
obj-$(CONFIG_HOSTFS) += hostfs/
obj-$(CONFIG_HPPFS) += hppfs/
obj-$(CONFIG_DEBUG_FS) += debugfs/
+obj-$(CONFIG_NDEV_FS) += ndevfs/
--- orig/fs/partitions/check.c
+++ mod/fs/partitions/check.c
@@ -18,6 +18,7 @@
#include <linux/fs.h>
#include <linux/kmod.h>
#include <linux/ctype.h>
+#include <linux/ndevfs.h>
#include <linux/devfs_fs_kernel.h>
#include "check.h"
@@ -283,6 +284,7 @@
p->nr_sects = 0;
p->reads = p->writes = p->read_sectors = p->write_sectors = 0;
devfs_remove("%s/part%d", disk->devfs_name, part);
+ ndevfs_remove(kobject_name(&p->kobj));
kobject_unregister(&p->kobj);
}
@@ -310,6 +312,7 @@
p->kobj.parent = &disk->kobj;
p->kobj.ktype = &ktype_part;
kobject_register(&p->kobj);
+ ndevfs_create(kobject_name(&p->kobj), MKDEV(disk->major, p->partno), 0);
disk->part[part-1] = p;
}
@@ -337,6 +340,8 @@
if ((err = kobject_add(&disk->kobj)))
return;
disk_sysfs_symlinks(disk);
+ ndevfs_create(kobject_name(&disk->kobj),
+ MKDEV(disk->major, disk->first_minor), 0);
kobject_hotplug(&disk->kobj, KOBJ_ADD);
/* No minors to use for partitions */
@@ -442,6 +447,7 @@
sysfs_remove_link(&disk->driverfs_dev->kobj, "block");
put_device(disk->driverfs_dev);
}
+ ndevfs_remove(kobject_name(&disk->kobj));
kobject_hotplug(&disk->kobj, KOBJ_REMOVE);
kobject_del(&disk->kobj);
}
--- /dev/null
+++ mod/fs/ndevfs/Makefile
@@ -0,0 +1,4 @@
+ndevfs-objs := inode.o
+
+obj-$(CONFIG_NDEV_FS) += ndevfs.o
+
--- /dev/null
+++ mod/fs/ndevfs/inode.c
@@ -0,0 +1,249 @@
+/*
+ * inode.c - part of ndevfs, a tiny little device file system
+ *
+ * Copyright (C) 2004,2005 Greg Kroah-Hartman <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * Written for all of the people out there who just hate userspace solutions.
+ *
+ */
+
+/* uncomment to get debug messages */
+#define DEBUG
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/device.h>
+#include <linux/ndevfs.h>
+
+#define MAGIC 0x64756d62
+
+struct entry {
+ struct list_head node;
+ struct dentry *dentry;
+ char name[BUS_ID_SIZE];
+};
+static LIST_HEAD(entries);
+
+static struct vfsmount *mount;
+static int mount_count;
+
+static struct file_operations stupid_file_ops = {
+ .read = generic_file_read,
+ .write = generic_file_write,
+ .mmap = generic_file_mmap,
+ .fsync = simple_sync_file,
+ .llseek = generic_file_llseek,
+};
+
+static struct inode *get_inode(struct super_block *sb, int mode, dev_t dev)
+{
+ struct inode *inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = 0;
+ inode->i_gid = 0;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ switch (mode & S_IFMT) {
+ default:
+ init_special_inode(inode, mode, dev);
+ break;
+ case S_IFREG:
+ inode->i_fop = &stupid_file_ops;
+ break;
+ case S_IFDIR:
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inode->i_nlink++;
+ break;
+ }
+ }
+ return inode;
+}
+
+/* SMP-safe */
+static int mknod(struct inode *dir, struct dentry *dentry,
+ int mode, dev_t dev)
+{
+ struct inode *inode = get_inode(dir->i_sb, mode, dev);
+ int error = -EPERM;
+
+ if (dentry->d_inode)
+ return -EEXIST;
+
+ if (inode) {
+ d_instantiate(dentry, inode);
+ dget(dentry);
+ error = 0;
+ }
+ return error;
+}
+
+static inline int positive(struct dentry *dentry)
+{
+ return dentry->d_inode && !d_unhashed(dentry);
+}
+
+static int fill_super(struct super_block *sb, void *data, int silent)
+{
+ static struct tree_descr files[] = {{""}};
+
+ return simple_fill_super(sb, MAGIC, files);
+}
+
+static struct super_block *get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, fill_super);
+}
+
+static void remove(struct dentry *dentry)
+{
+ struct dentry *parent;
+
+ if (!dentry)
+ return;
+
+ parent = dentry->d_parent;
+ if (!parent || !parent->d_inode)
+ return;
+
+ down(&parent->d_inode->i_sem);
+ if (positive(dentry)) {
+ if (dentry->d_inode) {
+ if (S_ISDIR(dentry->d_inode->i_mode))
+ simple_rmdir(parent->d_inode, dentry);
+ else
+ simple_unlink(parent->d_inode, dentry);
+ dput(dentry);
+ }
+ }
+ up(&parent->d_inode->i_sem);
+ simple_release_fs(&mount, &mount_count);
+}
+
+/**
+ * ndevfs_create - create a device node in ndevfs
+ *
+ * @name: the name to create
+ * @dev: the dev_t of the node
+ * @is_char: if the node is a char device or not
+ */
+void ndevfs_create(const char *name, dev_t dev, int is_char)
+{
+ struct dentry *parent;
+ struct dentry *dentry;
+ struct entry *entry;
+ int err;
+ int mode = S_IRUSR | S_IWUSR;
+
+ pr_debug("ndevfs: creating file '%s' with major %d and minor %d\n",
+ name, MAJOR(dev), MINOR(dev));
+
+ if (is_char)
+ mode |= S_IFCHR;
+ else
+ mode |= S_IFBLK;
+
+ err = simple_pin_fs("ndevfs", &mount, &mount_count);
+ if (err)
+ return;
+
+ /* everything is at the root fs, no directories allowed */
+ if (mount && mount->mnt_sb) {
+ parent = mount->mnt_sb->s_root;
+ } else {
+ pr_debug("%s: no parent?\n", __FUNCTION__);
+ goto error;
+ }
+
+ down(&parent->d_inode->i_sem);
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (!IS_ERR(dentry))
+ err = mknod(parent->d_inode, dentry, mode, dev);
+ else
+ err = PTR_ERR(dentry);
+ up(&parent->d_inode->i_sem);
+
+ if (err)
+ goto error;
+
+ entry = kmalloc(sizeof(struct entry), GFP_KERNEL);
+ if (!entry) {
+ remove(dentry);
+ err = -ENOMEM;
+ goto error;
+ }
+ entry->dentry = dentry;
+ strcpy(&entry->name[0], name);
+ list_add(&entry->node, &entries);
+ return;
+
+error:
+ pr_debug("%s failed with error %d\n", __FUNCTION__, err);
+ simple_release_fs(&mount, &mount_count);
+}
+EXPORT_SYMBOL_GPL(ndevfs_create);
+
+/**
+ * ndevfs_remove - removes the node from the fs
+ *
+ * @name: the name to remove.
+ */
+void ndevfs_remove(const char *name)
+{
+ struct entry *entry;
+ struct dentry *dentry = NULL;
+
+ pr_debug("ndevfs: removing file '%s'\n", name);
+
+ list_for_each_entry(entry, &entries, node) {
+ if (strcmp(name, &entry->name[0]) == 0) {
+ dentry = entry->dentry;
+ break;
+ }
+ }
+ if (!dentry) {
+ pr_debug("%s: can't find %s\n", __FUNCTION__, name);
+ return;
+ }
+ remove (dentry);
+}
+EXPORT_SYMBOL_GPL(ndevfs_remove);
+
+static struct file_system_type fs_type = {
+ .owner = THIS_MODULE,
+ .name = "ndevfs",
+ .get_sb = get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+static int __init ndevfs_init(void)
+{
+ return register_filesystem(&fs_type);
+}
+
+static void __exit ndevfs_exit(void)
+{
+ simple_release_fs(&mount, &mount_count);
+ unregister_filesystem(&fs_type);
+}
+
+core_initcall(ndevfs_init);
+module_exit(ndevfs_exit);
+MODULE_LICENSE("GPL");
+
--- /dev/null
+++ mod/include/linux/ndevfs.h
@@ -0,0 +1,13 @@
+#ifndef _NDEVFS_H_
+#define _NDEVFS_H_
+
+#if defined(CONFIG_NDEV_FS)
+extern void ndevfs_create(const char *name, dev_t dev, int is_char);
+extern void ndevfs_remove(const char *name);
+#else
+static inline void ndevfs_create(const char *name, dev_t dev, int is_char) {}
+static inline void ndevfs_remove(const char *name) {}
+#endif
+
+#endif
+
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