linux-sg2042/fs/openpromfs/inode.c

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/* inode.c: /proc/openprom handling routines
*
* Copyright (C) 1996-1999 Jakub Jelinek (jakub@redhat.com)
* Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/magic.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
static DEFINE_MUTEX(op_mutex);
#define OPENPROM_ROOT_INO 0
enum op_inode_type {
op_inode_node,
op_inode_prop,
};
union op_inode_data {
struct device_node *node;
struct property *prop;
};
struct op_inode_info {
struct inode vfs_inode;
enum op_inode_type type;
union op_inode_data u;
};
static struct inode *openprom_iget(struct super_block *sb, ino_t ino);
static inline struct op_inode_info *OP_I(struct inode *inode)
{
return container_of(inode, struct op_inode_info, vfs_inode);
}
static int is_string(unsigned char *p, int len)
{
int i;
for (i = 0; i < len; i++) {
unsigned char val = p[i];
if ((i && !val) ||
(val >= ' ' && val <= '~'))
continue;
return 0;
}
return 1;
}
static int property_show(struct seq_file *f, void *v)
{
struct property *prop = f->private;
void *pval;
int len;
len = prop->length;
pval = prop->value;
if (is_string(pval, len)) {
while (len > 0) {
int n = strlen(pval);
seq_printf(f, "%s", (char *) pval);
/* Skip over the NULL byte too. */
pval += n + 1;
len -= n + 1;
if (len > 0)
seq_printf(f, " + ");
}
} else {
if (len & 3) {
while (len) {
len--;
if (len)
seq_printf(f, "%02x.",
*(unsigned char *) pval);
else
seq_printf(f, "%02x",
*(unsigned char *) pval);
pval++;
}
} else {
while (len >= 4) {
len -= 4;
if (len)
seq_printf(f, "%08x.",
*(unsigned int *) pval);
else
seq_printf(f, "%08x",
*(unsigned int *) pval);
pval += 4;
}
}
}
seq_printf(f, "\n");
return 0;
}
static void *property_start(struct seq_file *f, loff_t *pos)
{
if (*pos == 0)
return pos;
return NULL;
}
static void *property_next(struct seq_file *f, void *v, loff_t *pos)
{
(*pos)++;
return NULL;
}
static void property_stop(struct seq_file *f, void *v)
{
/* Nothing to do */
}
static const struct seq_operations property_op = {
.start = property_start,
.next = property_next,
.stop = property_stop,
.show = property_show
};
static int property_open(struct inode *inode, struct file *file)
{
struct op_inode_info *oi = OP_I(inode);
int ret;
BUG_ON(oi->type != op_inode_prop);
ret = seq_open(file, &property_op);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = oi->u.prop;
}
return ret;
}
static const struct file_operations openpromfs_prop_ops = {
.open = property_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int openpromfs_readdir(struct file *, void *, filldir_t);
static const struct file_operations openprom_operations = {
.read = generic_read_dir,
.readdir = openpromfs_readdir,
.llseek = generic_file_llseek,
};
static struct dentry *openpromfs_lookup(struct inode *, struct dentry *, struct nameidata *);
static const struct inode_operations openprom_inode_operations = {
.lookup = openpromfs_lookup,
};
static struct dentry *openpromfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct op_inode_info *ent_oi, *oi = OP_I(dir);
struct device_node *dp, *child;
struct property *prop;
enum op_inode_type ent_type;
union op_inode_data ent_data;
const char *name;
struct inode *inode;
unsigned int ino;
int len;
BUG_ON(oi->type != op_inode_node);
dp = oi->u.node;
name = dentry->d_name.name;
len = dentry->d_name.len;
mutex_lock(&op_mutex);
child = dp->child;
while (child) {
int n = strlen(child->path_component_name);
if (len == n &&
!strncmp(child->path_component_name, name, len)) {
ent_type = op_inode_node;
ent_data.node = child;
ino = child->unique_id;
goto found;
}
child = child->sibling;
}
prop = dp->properties;
while (prop) {
int n = strlen(prop->name);
if (len == n && !strncmp(prop->name, name, len)) {
ent_type = op_inode_prop;
ent_data.prop = prop;
ino = prop->unique_id;
goto found;
}
prop = prop->next;
}
mutex_unlock(&op_mutex);
return ERR_PTR(-ENOENT);
found:
inode = openprom_iget(dir->i_sb, ino);
mutex_unlock(&op_mutex);
if (IS_ERR(inode))
return ERR_CAST(inode);
ent_oi = OP_I(inode);
ent_oi->type = ent_type;
ent_oi->u = ent_data;
switch (ent_type) {
case op_inode_node:
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
inode->i_op = &openprom_inode_operations;
inode->i_fop = &openprom_operations;
inode->i_nlink = 2;
break;
case op_inode_prop:
if (!strcmp(dp->name, "options") && (len == 17) &&
!strncmp (name, "security-password", 17))
inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
else
inode->i_mode = S_IFREG | S_IRUGO;
inode->i_fop = &openpromfs_prop_ops;
inode->i_nlink = 1;
inode->i_size = ent_oi->u.prop->length;
break;
}
d_add(dentry, inode);
return NULL;
}
static int openpromfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
struct op_inode_info *oi = OP_I(inode);
struct device_node *dp = oi->u.node;
struct device_node *child;
struct property *prop;
unsigned int ino;
int i;
mutex_lock(&op_mutex);
ino = inode->i_ino;
i = filp->f_pos;
switch (i) {
case 0:
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
goto out;
i++;
filp->f_pos++;
/* fall thru */
case 1:
if (filldir(dirent, "..", 2, i,
(dp->parent == NULL ?
OPENPROM_ROOT_INO :
dp->parent->unique_id), DT_DIR) < 0)
goto out;
i++;
filp->f_pos++;
/* fall thru */
default:
i -= 2;
/* First, the children nodes as directories. */
child = dp->child;
while (i && child) {
child = child->sibling;
i--;
}
while (child) {
if (filldir(dirent,
child->path_component_name,
strlen(child->path_component_name),
filp->f_pos, child->unique_id, DT_DIR) < 0)
goto out;
filp->f_pos++;
child = child->sibling;
}
/* Next, the properties as files. */
prop = dp->properties;
while (i && prop) {
prop = prop->next;
i--;
}
while (prop) {
if (filldir(dirent, prop->name, strlen(prop->name),
filp->f_pos, prop->unique_id, DT_REG) < 0)
goto out;
filp->f_pos++;
prop = prop->next;
}
}
out:
mutex_unlock(&op_mutex);
return 0;
}
static struct kmem_cache *op_inode_cachep;
static struct inode *openprom_alloc_inode(struct super_block *sb)
{
struct op_inode_info *oi;
oi = kmem_cache_alloc(op_inode_cachep, GFP_KERNEL);
if (!oi)
return NULL;
return &oi->vfs_inode;
}
static void openprom_destroy_inode(struct inode *inode)
{
kmem_cache_free(op_inode_cachep, OP_I(inode));
}
static struct inode *openprom_iget(struct super_block *sb, ino_t ino)
{
struct inode *inode;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
if (inode->i_ino == OPENPROM_ROOT_INO) {
inode->i_op = &openprom_inode_operations;
inode->i_fop = &openprom_operations;
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
}
unlock_new_inode(inode);
}
return inode;
}
static int openprom_remount(struct super_block *sb, int *flags, char *data)
{
*flags |= MS_NOATIME;
return 0;
}
static const struct super_operations openprom_sops = {
.alloc_inode = openprom_alloc_inode,
.destroy_inode = openprom_destroy_inode,
.statfs = simple_statfs,
.remount_fs = openprom_remount,
};
static int openprom_fill_super(struct super_block *s, void *data, int silent)
{
struct inode *root_inode;
struct op_inode_info *oi;
int ret;
s->s_flags |= MS_NOATIME;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = OPENPROM_SUPER_MAGIC;
s->s_op = &openprom_sops;
s->s_time_gran = 1;
root_inode = openprom_iget(s, OPENPROM_ROOT_INO);
if (IS_ERR(root_inode)) {
ret = PTR_ERR(root_inode);
goto out_no_root;
}
oi = OP_I(root_inode);
oi->type = op_inode_node;
oi->u.node = of_find_node_by_path("/");
s->s_root = d_alloc_root(root_inode);
if (!s->s_root)
goto out_no_root_dentry;
return 0;
out_no_root_dentry:
iput(root_inode);
ret = -ENOMEM;
out_no_root:
printk("openprom_fill_super: get root inode failed\n");
return ret;
}
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:02:57 +08:00
static int openprom_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:02:57 +08:00
return get_sb_single(fs_type, flags, data, openprom_fill_super, mnt);
}
static struct file_system_type openprom_fs_type = {
.owner = THIS_MODULE,
.name = "openpromfs",
.get_sb = openprom_get_sb,
.kill_sb = kill_anon_super,
};
static void op_inode_init_once(void *data)
{
struct op_inode_info *oi = (struct op_inode_info *) data;
inode_init_once(&oi->vfs_inode);
}
static int __init init_openprom_fs(void)
{
int err;
op_inode_cachep = kmem_cache_create("op_inode_cache",
sizeof(struct op_inode_info),
0,
(SLAB_RECLAIM_ACCOUNT |
SLAB_MEM_SPREAD),
op_inode_init_once);
if (!op_inode_cachep)
return -ENOMEM;
err = register_filesystem(&openprom_fs_type);
if (err)
kmem_cache_destroy(op_inode_cachep);
return err;
}
static void __exit exit_openprom_fs(void)
{
unregister_filesystem(&openprom_fs_type);
kmem_cache_destroy(op_inode_cachep);
}
module_init(init_openprom_fs)
module_exit(exit_openprom_fs)
MODULE_LICENSE("GPL");