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/* -*- c -*- --------------------------------------------------------------- *
*
* linux/fs/autofs/root.c
*
* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
* Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* ------------------------------------------------------------------------- */
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/param.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include "autofs_i.h"
static struct dentry *autofs4_dir_lookup(struct inode *,struct dentry *);
static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
static int autofs4_dir_unlink(struct inode *,struct dentry *);
static int autofs4_dir_rmdir(struct inode *,struct dentry *);
static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
static struct dentry *autofs4_root_lookup(struct inode *,struct dentry *);
struct file_operations autofs4_root_operations = {
read: generic_read_dir,
readdir: dcache_readdir,
ioctl: autofs4_root_ioctl,
};
struct file_operations autofs4_dir_operations = {
read: generic_read_dir,
readdir: dcache_readdir,
};
struct inode_operations autofs4_root_inode_operations = {
lookup: autofs4_root_lookup,
unlink: autofs4_dir_unlink,
symlink: autofs4_dir_symlink,
mkdir: autofs4_dir_mkdir,
rmdir: autofs4_dir_rmdir,
};
struct inode_operations autofs4_dir_inode_operations = {
lookup: autofs4_dir_lookup,
unlink: autofs4_dir_unlink,
symlink: autofs4_dir_symlink,
mkdir: autofs4_dir_mkdir,
rmdir: autofs4_dir_rmdir,
};
/* Update usage from here to top of tree, so that scan of
top-level directories will give a useful result */
static void autofs4_update_usage(struct dentry *dentry)
{
struct dentry *top = dentry->d_sb->s_root;
for(; dentry != top; dentry = dentry->d_parent) {
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
update_atime(dentry->d_inode);
ino->last_used = jiffies;
}
}
}
static int try_to_fill_dentry(struct dentry *dentry,
struct super_block *sb,
struct autofs_sb_info *sbi)
{
struct autofs_info *de_info = autofs4_dentry_ino(dentry);
int status = 0;
/* Block on any pending expiry here; invalidate the dentry
when expiration is done to trigger mount request with a new
dentry */
if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
DPRINTK(("try_to_fill_entry: waiting for expire %p name=%.*s, flags&PENDING=%s de_info=%p de_info->flags=%x\n",
dentry, dentry->d_name.len, dentry->d_name.name,
dentry->d_flags & DCACHE_AUTOFS_PENDING?"t":"f",
de_info, de_info?de_info->flags:0));
status = autofs4_wait(sbi, &dentry->d_name, NFY_NONE);
DPRINTK(("try_to_fill_entry: expire done status=%d\n", status));
return 0;
}
DPRINTK(("try_to_fill_entry: dentry=%p %.*s ino=%p\n",
dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode));
/* Wait for a pending mount, triggering one if there isn't one already */
while(dentry->d_inode == NULL) {
DPRINTK(("try_to_fill_entry: waiting for mount name=%.*s, de_info=%p de_info->flags=%x\n",
dentry->d_name.len, dentry->d_name.name,
de_info, de_info?de_info->flags:0));
status = autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT);
DPRINTK(("try_to_fill_entry: mount done status=%d\n", status));
if (status && dentry->d_inode)
return 0; /* Try to get the kernel to invalidate this dentry */
/* Turn this into a real negative dentry? */
if (status == -ENOENT) {
dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
return 1;
} else if (status) {
/* Return a negative dentry, but leave it "pending" */
return 1;
}
}
/* If this is an unused directory that isn't a mount point,
bitch at the daemon and fix it in user space */
spin_lock(&dcache_lock);
if (S_ISDIR(dentry->d_inode->i_mode) &&
!d_mountpoint(dentry) &&
list_empty(&dentry->d_subdirs)) {
DPRINTK(("try_to_fill_entry: mounting existing dir\n"));
spin_unlock(&dcache_lock);
return autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT) == 0;
}
spin_unlock(&dcache_lock);
/* We don't update the usages for the autofs daemon itself, this
is necessary for recursive autofs mounts */
if (!autofs4_oz_mode(sbi))
autofs4_update_usage(dentry);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
return 1;
}
/*
* Revalidate is called on every cache lookup. Some of those
* cache lookups may actually happen while the dentry is not
* yet completely filled in, and revalidate has to delay such
* lookups..
*/
static int autofs4_root_revalidate(struct dentry * dentry, int flags)
{
struct inode * dir = dentry->d_parent->d_inode;
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino;
int oz_mode = autofs4_oz_mode(sbi);
/* Pending dentry */
if (autofs4_ispending(dentry)) {
if (autofs4_oz_mode(sbi))
return 1;
else
return try_to_fill_dentry(dentry, dir->i_sb, sbi);
}
/* Negative dentry.. invalidate if "old" */
if (dentry->d_inode == NULL)
return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
ino = autofs4_dentry_ino(dentry);
/* Check for a non-mountpoint directory with no contents */
spin_lock(&dcache_lock);
if (S_ISDIR(dentry->d_inode->i_mode) &&
!d_mountpoint(dentry) &&
list_empty(&dentry->d_subdirs)) {
DPRINTK(("autofs_root_revalidate: dentry=%p %.*s, emptydir\n",
dentry, dentry->d_name.len, dentry->d_name.name));
spin_unlock(&dcache_lock);
if (oz_mode)
return 1;
else
return try_to_fill_dentry(dentry, dir->i_sb, sbi);
}
spin_unlock(&dcache_lock);
/* Update the usage list */
if (!oz_mode)
autofs4_update_usage(dentry);
return 1;
}
static int autofs4_revalidate(struct dentry *dentry, int flags)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
if (!autofs4_oz_mode(sbi))
autofs4_update_usage(dentry);
return 1;
}
static void autofs4_dentry_release(struct dentry *de)
{
struct autofs_info *inf;
lock_kernel();
DPRINTK(("autofs4_dentry_release: releasing %p\n", de));
inf = autofs4_dentry_ino(de);
de->d_fsdata = NULL;
if (inf) {
inf->dentry = NULL;
inf->inode = NULL;
autofs4_free_ino(inf);
}
unlock_kernel();
}
/* For dentries of directories in the root dir */
static struct dentry_operations autofs4_root_dentry_operations = {
d_revalidate: autofs4_root_revalidate,
d_release: autofs4_dentry_release,
};
/* For other dentries */
static struct dentry_operations autofs4_dentry_operations = {
d_revalidate: autofs4_revalidate,
d_release: autofs4_dentry_release,
};
/* Lookups in non-root dirs never find anything - if it's there, it's
already in the dcache */
static struct dentry *autofs4_dir_lookup(struct inode *dir, struct dentry *dentry)
{
#if 0
DPRINTK(("autofs_dir_lookup: ignoring lookup of %.*s/%.*s\n",
dentry->d_parent->d_name.len, dentry->d_parent->d_name.name,
dentry->d_name.len, dentry->d_name.name));
#endif
dentry->d_fsdata = NULL;
d_add(dentry, NULL);
return NULL;
}
/* Lookups in the root directory */
static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi;
int oz_mode;
DPRINTK(("autofs_root_lookup: name = %.*s\n",
dentry->d_name.len, dentry->d_name.name));
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
sbi = autofs4_sbi(dir->i_sb);
oz_mode = autofs4_oz_mode(sbi);
DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
current->pid, current->pgrp, sbi->catatonic, oz_mode));
/*
* Mark the dentry incomplete, but add it. This is needed so
* that the VFS layer knows about the dentry, and we can count
* on catching any lookups through the revalidate.
*
* Let all the hard work be done by the revalidate function that
* needs to be able to do this anyway..
*
* We need to do this before we release the directory semaphore.
*/
dentry->d_op = &autofs4_root_dentry_operations;
if (!oz_mode)
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
dentry->d_fsdata = NULL;
d_add(dentry, NULL);
if (dentry->d_op && dentry->d_op->d_revalidate) {
up(&dir->i_sem);
(dentry->d_op->d_revalidate)(dentry, 0);
down(&dir->i_sem);
}
/*
* If we are still pending, check if we had to handle
* a signal. If so we can force a restart..
*/
if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
if (signal_pending(current))
return ERR_PTR(-ERESTARTNOINTR);
}
/*
* If this dentry is unhashed, then we shouldn't honour this
* lookup even if the dentry is positive. Returning ENOENT here
* doesn't do the right thing for all system calls, but it should
* be OK for the operations we permit from an autofs.
*/
if ( dentry->d_inode && d_unhashed(dentry) )
return ERR_PTR(-ENOENT);
return NULL;
}
static int autofs4_dir_symlink(struct inode *dir,
struct dentry *dentry,
const char *symname)
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
struct inode *inode;
char *cp;
DPRINTK(("autofs_dir_symlink: %s <- %.*s\n", symname,
dentry->d_name.len, dentry->d_name.name));
if (!autofs4_oz_mode(sbi))
return -EACCES;
ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
if (ino == NULL)
return -ENOSPC;
ino->size = strlen(symname);
ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
if (cp == NULL) {
kfree(ino);
return -ENOSPC;
}
strcpy(cp, symname);
inode = autofs4_get_inode(dir->i_sb, ino);
d_instantiate(dentry, inode);
if (dir == dir->i_sb->s_root->d_inode)
dentry->d_op = &autofs4_root_dentry_operations;
else
dentry->d_op = &autofs4_dentry_operations;
dentry->d_fsdata = ino;
ino->dentry = dget(dentry);
ino->inode = inode;
dir->i_mtime = CURRENT_TIME;
return 0;
}
/*
* NOTE!
*
* Normal filesystems would do a "d_delete()" to tell the VFS dcache
* that the file no longer exists. However, doing that means that the
* VFS layer can turn the dentry into a negative dentry. We don't want
* this, because since the unlink is probably the result of an expire.
* We simply d_drop it, which allows the dentry lookup to remount it
* if necessary.
*
* If a process is blocked on the dentry waiting for the expire to finish,
* it will invalidate the dentry and try to mount with a new one.
*
* Also see autofs_dir_rmdir()..
*/
static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
/* This allows root to remove symlinks */
if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
return -EACCES;
dput(ino->dentry);
dentry->d_inode->i_size = 0;
dentry->d_inode->i_nlink = 0;
dir->i_mtime = CURRENT_TIME;
d_drop(dentry);
return 0;
}
static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (!autofs4_oz_mode(sbi))
return -EACCES;
spin_lock(&dcache_lock);
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&dcache_lock);
return -ENOTEMPTY;
}
list_del_init(&dentry->d_hash);
spin_unlock(&dcache_lock);
dput(ino->dentry);
dentry->d_inode->i_size = 0;
dentry->d_inode->i_nlink = 0;
if (dir->i_nlink)
dir->i_nlink--;
return 0;
}
static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
struct inode *inode;
if ( !autofs4_oz_mode(sbi) )
return -EACCES;
DPRINTK(("autofs_dir_mkdir: dentry %p, creating %.*s\n",
dentry, dentry->d_name.len, dentry->d_name.name));
ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
if (ino == NULL)
return -ENOSPC;
inode = autofs4_get_inode(dir->i_sb, ino);
d_instantiate(dentry, inode);
if (dir == dir->i_sb->s_root->d_inode)
dentry->d_op = &autofs4_root_dentry_operations;
else
dentry->d_op = &autofs4_dentry_operations;
dentry->d_fsdata = ino;
ino->dentry = dget(dentry);
ino->inode = inode;
dir->i_nlink++;
dir->i_mtime = CURRENT_TIME;
return 0;
}
/* Get/set timeout ioctl() operation */
static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
unsigned long *p)
{
int rv;
unsigned long ntimeout;
if ( (rv = get_user(ntimeout, p)) ||
(rv = put_user(sbi->exp_timeout/HZ, p)) )
return rv;
if ( ntimeout > ULONG_MAX/HZ )
sbi->exp_timeout = 0;
else
sbi->exp_timeout = ntimeout * HZ;
return 0;
}
/* Return protocol version */
static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int *p)
{
return put_user(sbi->version, p);
}
/* Identify autofs_dentries - this is so we can tell if there's
an extra dentry refcount or not. We only hold a refcount on the
dentry if its non-negative (ie, d_inode != NULL)
*/
int is_autofs4_dentry(struct dentry *dentry)
{
return dentry && dentry->d_inode &&
(dentry->d_op == &autofs4_root_dentry_operations ||
dentry->d_op == &autofs4_dentry_operations) &&
dentry->d_fsdata != NULL;
}
/*
* ioctl()'s on the root directory is the chief method for the daemon to
* generate kernel reactions
*/
static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
cmd,arg,sbi,current->pgrp));
if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
_IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
return -ENOTTY;
if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
return -EPERM;
switch(cmd) {
case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
autofs4_catatonic_mode(sbi);
return 0;
case AUTOFS_IOC_PROTOVER: /* Get protocol version */
return autofs4_get_protover(sbi, (int *)arg);
case AUTOFS_IOC_SETTIMEOUT:
return autofs4_get_set_timeout(sbi,(unsigned long *)arg);
/* return a single thing to expire */
case AUTOFS_IOC_EXPIRE:
return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi,
(struct autofs_packet_expire *)arg);
/* same as above, but can send multiple expires through pipe */
case AUTOFS_IOC_EXPIRE_MULTI:
return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi,
(int *)arg);
default:
return -ENOSYS;
}
}
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