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linux/fs/autofs4/root.c

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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>
* Copyright 2001-2006 Ian Kent <raven@themaw.net>
*
* 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/capability.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/param.h>
#include <linux/time.h>
#include "autofs_i.h"
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 int autofs4_dir_open(struct inode *inode, struct file *file);
static int autofs4_dir_close(struct inode *inode, struct file *file);
static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
static void *autofs4_follow_link(struct dentry *, struct nameidata *);
const struct file_operations autofs4_root_operations = {
.open = dcache_dir_open,
.release = dcache_dir_close,
.read = generic_read_dir,
.readdir = autofs4_root_readdir,
.ioctl = autofs4_root_ioctl,
};
const struct file_operations autofs4_dir_operations = {
.open = autofs4_dir_open,
.release = autofs4_dir_close,
.read = generic_read_dir,
.readdir = autofs4_dir_readdir,
};
const struct inode_operations autofs4_indirect_root_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.symlink = autofs4_dir_symlink,
.mkdir = autofs4_dir_mkdir,
.rmdir = autofs4_dir_rmdir,
};
const struct inode_operations autofs4_direct_root_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.mkdir = autofs4_dir_mkdir,
.rmdir = autofs4_dir_rmdir,
.follow_link = autofs4_follow_link,
};
const struct inode_operations autofs4_dir_inode_operations = {
.lookup = autofs4_lookup,
.unlink = autofs4_dir_unlink,
.symlink = autofs4_dir_symlink,
.mkdir = autofs4_dir_mkdir,
.rmdir = autofs4_dir_rmdir,
};
static int autofs4_root_readdir(struct file *file, void *dirent,
filldir_t filldir)
{
struct autofs_sb_info *sbi = autofs4_sbi(file->f_path.dentry->d_sb);
int oz_mode = autofs4_oz_mode(sbi);
DPRINTK("called, filp->f_pos = %lld", file->f_pos);
/*
* Don't set reghost flag if:
* 1) f_pos is larger than zero -- we've already been here.
* 2) we haven't even enabled reghosting in the 1st place.
* 3) this is the daemon doing a readdir
*/
if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
sbi->needs_reghost = 1;
DPRINTK("needs_reghost = %d", sbi->needs_reghost);
return dcache_readdir(file, dirent, filldir);
}
static int autofs4_dir_open(struct inode *inode, struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct vfsmount *mnt = file->f_path.mnt;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct dentry *cursor;
int status;
status = dcache_dir_open(inode, file);
if (status)
goto out;
cursor = file->private_data;
cursor->d_fsdata = NULL;
DPRINTK("file=%p dentry=%p %.*s",
file, dentry, dentry->d_name.len, dentry->d_name.name);
if (autofs4_oz_mode(sbi))
goto out;
if (autofs4_ispending(dentry)) {
DPRINTK("dentry busy");
dcache_dir_close(inode, file);
status = -EBUSY;
goto out;
}
status = -ENOENT;
if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
struct nameidata nd;
int empty, ret;
/* In case there are stale directory dentrys from a failed mount */
spin_lock(&dcache_lock);
empty = list_empty(&dentry->d_subdirs);
spin_unlock(&dcache_lock);
if (!empty)
d_invalidate(dentry);
nd.flags = LOOKUP_DIRECTORY;
ret = (dentry->d_op->d_revalidate)(dentry, &nd);
if (ret <= 0) {
if (ret < 0)
status = ret;
dcache_dir_close(inode, file);
goto out;
}
}
if (d_mountpoint(dentry)) {
struct file *fp = NULL;
struct path fp_path = { .dentry = dentry, .mnt = mnt };
path_get(&fp_path);
if (!autofs4_follow_mount(&fp_path.mnt, &fp_path.dentry)) {
path_put(&fp_path);
dcache_dir_close(inode, file);
goto out;
}
fp = dentry_open(fp_path.dentry, fp_path.mnt, file->f_flags);
status = PTR_ERR(fp);
if (IS_ERR(fp)) {
dcache_dir_close(inode, file);
goto out;
}
cursor->d_fsdata = fp;
}
return 0;
out:
return status;
}
static int autofs4_dir_close(struct inode *inode, struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct dentry *cursor = file->private_data;
int status = 0;
DPRINTK("file=%p dentry=%p %.*s",
file, dentry, dentry->d_name.len, dentry->d_name.name);
if (autofs4_oz_mode(sbi))
goto out;
if (autofs4_ispending(dentry)) {
DPRINTK("dentry busy");
status = -EBUSY;
goto out;
}
if (d_mountpoint(dentry)) {
struct file *fp = cursor->d_fsdata;
if (!fp) {
status = -ENOENT;
goto out;
}
filp_close(fp, current->files);
}
out:
dcache_dir_close(inode, file);
return status;
}
static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
{
struct dentry *dentry = file->f_path.dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct dentry *cursor = file->private_data;
int status;
DPRINTK("file=%p dentry=%p %.*s",
file, dentry, dentry->d_name.len, dentry->d_name.name);
if (autofs4_oz_mode(sbi))
goto out;
if (autofs4_ispending(dentry)) {
DPRINTK("dentry busy");
return -EBUSY;
}
if (d_mountpoint(dentry)) {
struct file *fp = cursor->d_fsdata;
if (!fp)
return -ENOENT;
if (!fp->f_op || !fp->f_op->readdir)
goto out;
status = vfs_readdir(fp, filldir, dirent);
file->f_pos = fp->f_pos;
if (status)
autofs4_copy_atime(file, fp);
return status;
}
out:
return dcache_readdir(file, dirent, filldir);
}
static int try_to_fill_dentry(struct dentry *dentry, int flags)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
struct dentry *new;
int status;
/* Block on any pending expiry here; invalidate the dentry
when expiration is done to trigger mount request with a new
dentry */
if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
DPRINTK("waiting for expire %p name=%.*s",
dentry, dentry->d_name.len, dentry->d_name.name);
status = autofs4_wait(sbi, dentry, NFY_NONE);
DPRINTK("expire done status=%d", status);
/*
* If the directory still exists the mount request must
* continue otherwise it can't be followed at the right
* time during the walk.
*/
status = d_invalidate(dentry);
if (status != -EBUSY)
return -EAGAIN;
}
DPRINTK("dentry=%p %.*s ino=%p",
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
*/
if (dentry->d_inode == NULL) {
DPRINTK("waiting for mount name=%.*s",
dentry->d_name.len, dentry->d_name.name);
status = autofs4_wait(sbi, dentry, NFY_MOUNT);
DPRINTK("mount done status=%d", status);
/* Turn this into a real negative dentry? */
if (status == -ENOENT) {
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
return status;
} else if (status) {
/* Return a negative dentry, but leave it "pending" */
return status;
}
/* Trigger mount for path component or follow link */
} else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
current->link_count) {
DPRINTK("waiting for mount name=%.*s",
dentry->d_name.len, dentry->d_name.name);
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
status = autofs4_wait(sbi, dentry, NFY_MOUNT);
DPRINTK("mount done status=%d", status);
if (status) {
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
return status;
}
}
/* Initialize expiry counter after successful mount */
if (ino)
ino->last_used = jiffies;
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
/*
* The dentry that is passed in from lookup may not be the one
* we end up using, as mkdir can create a new one. If this
* happens, and another process tries the lookup at the same time,
* it will set the PENDING flag on this new dentry, but add itself
* to our waitq. Then, if after the lookup succeeds, the first
* process that requested the mount performs another lookup of the
* same directory, it will show up as still pending! So, we need
* to redo the lookup here and clear pending on that dentry.
*/
if (d_unhashed(dentry)) {
new = d_lookup(dentry->d_parent, &dentry->d_name);
if (new) {
spin_lock(&new->d_lock);
new->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&new->d_lock);
dput(new);
}
}
return 0;
}
/* For autofs direct mounts the follow link triggers the mount */
static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
int oz_mode = autofs4_oz_mode(sbi);
unsigned int lookup_type;
int status;
DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
nd->flags);
/* If it's our master or we shouldn't trigger a mount we're done */
lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
if (oz_mode || !lookup_type)
goto done;
/* If an expire request is pending wait for it. */
if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
DPRINTK("waiting for active request %p name=%.*s",
dentry, dentry->d_name.len, dentry->d_name.name);
status = autofs4_wait(sbi, dentry, NFY_NONE);
DPRINTK("request done status=%d", status);
}
/*
* If the dentry contains directories then it is an
* autofs multi-mount with no root mount offset. So
* don't try to mount it again.
*/
spin_lock(&dcache_lock);
if (!d_mountpoint(dentry) && __simple_empty(dentry)) {
spin_unlock(&dcache_lock);
status = try_to_fill_dentry(dentry, 0);
if (status)
goto out_error;
/*
* The mount succeeded but if there is no root mount
* it must be an autofs multi-mount with no root offset
* so we don't need to follow the mount.
*/
if (d_mountpoint(dentry)) {
if (!autofs4_follow_mount(&nd->path.mnt,
&nd->path.dentry)) {
status = -ENOENT;
goto out_error;
}
}
goto done;
}
spin_unlock(&dcache_lock);
done:
return NULL;
out_error:
path_put(&nd->path);
return ERR_PTR(status);
}
/*
* 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_revalidate(struct dentry *dentry, struct nameidata *nd)
{
struct inode *dir = dentry->d_parent->d_inode;
struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
int oz_mode = autofs4_oz_mode(sbi);
int flags = nd ? nd->flags : 0;
int status = 1;
/* Pending dentry */
if (autofs4_ispending(dentry)) {
/* The daemon never causes a mount to trigger */
if (oz_mode)
return 1;
/*
* A zero status is success otherwise we have a
* negative error code.
*/
status = try_to_fill_dentry(dentry, flags);
if (status == 0)
return 1;
/*
* A status of EAGAIN here means that the dentry has gone
* away while waiting for an expire to complete. If we are
* racing with expire lookup will wait for it so this must
* be a revalidate and we need to send it to lookup.
*/
if (status == -EAGAIN)
return 0;
return status;
}
/* Negative dentry.. invalidate if "old" */
if (dentry->d_inode == NULL)
return 0;
/* Check for a non-mountpoint directory with no contents */
spin_lock(&dcache_lock);
if (S_ISDIR(dentry->d_inode->i_mode) &&
!d_mountpoint(dentry) &&
__simple_empty(dentry)) {
DPRINTK("dentry=%p %.*s, emptydir",
dentry, dentry->d_name.len, dentry->d_name.name);
spin_unlock(&dcache_lock);
/* The daemon never causes a mount to trigger */
if (oz_mode)
return 1;
/*
* A zero status is success otherwise we have a
* negative error code.
*/
status = try_to_fill_dentry(dentry, flags);
if (status == 0)
return 1;
return status;
}
spin_unlock(&dcache_lock);
return 1;
}
void autofs4_dentry_release(struct dentry *de)
{
struct autofs_info *inf;
DPRINTK("releasing %p", de);
inf = autofs4_dentry_ino(de);
de->d_fsdata = NULL;
if (inf) {
struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
if (sbi) {
spin_lock(&sbi->rehash_lock);
if (!list_empty(&inf->rehash))
list_del(&inf->rehash);
spin_unlock(&sbi->rehash_lock);
}
inf->dentry = NULL;
inf->inode = NULL;
autofs4_free_ino(inf);
}
}
/* For dentries of directories in the root dir */
static struct dentry_operations autofs4_root_dentry_operations = {
.d_revalidate = autofs4_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,
};
static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
{
unsigned int len = name->len;
unsigned int hash = name->hash;
const unsigned char *str = name->name;
struct list_head *p, *head;
spin_lock(&dcache_lock);
spin_lock(&sbi->rehash_lock);
head = &sbi->rehash_list;
list_for_each(p, head) {
struct autofs_info *ino;
struct dentry *dentry;
struct qstr *qstr;
ino = list_entry(p, struct autofs_info, rehash);
dentry = ino->dentry;
spin_lock(&dentry->d_lock);
/* Bad luck, we've already been dentry_iput */
if (!dentry->d_inode)
goto next;
qstr = &dentry->d_name;
if (dentry->d_name.hash != hash)
goto next;
if (dentry->d_parent != parent)
goto next;
if (qstr->len != len)
goto next;
if (memcmp(qstr->name, str, len))
goto next;
if (d_unhashed(dentry)) {
struct inode *inode = dentry->d_inode;
ino = autofs4_dentry_ino(dentry);
list_del_init(&ino->rehash);
dget(dentry);
/*
* Make the rehashed dentry negative so the VFS
* behaves as it should.
*/
if (inode) {
dentry->d_inode = NULL;
list_del_init(&dentry->d_alias);
spin_unlock(&dentry->d_lock);
spin_unlock(&sbi->rehash_lock);
spin_unlock(&dcache_lock);
iput(inode);
return dentry;
}
spin_unlock(&dentry->d_lock);
spin_unlock(&sbi->rehash_lock);
spin_unlock(&dcache_lock);
return dentry;
}
next:
spin_unlock(&dentry->d_lock);
}
spin_unlock(&sbi->rehash_lock);
spin_unlock(&dcache_lock);
return NULL;
}
/* Lookups in the root directory */
static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
struct autofs_sb_info *sbi;
struct dentry *unhashed;
int oz_mode;
DPRINTK("name = %.*s",
dentry->d_name.len, dentry->d_name.name);
/* File name too long to exist */
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
sbi = autofs4_sbi(dir->i_sb);
oz_mode = autofs4_oz_mode(sbi);
DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name);
if (!unhashed) {
/*
* Mark the dentry incomplete but don't hash it. We do this
* to serialize our inode creation operations (symlink and
* mkdir) which prevents deadlock during the callback to
* the daemon. Subsequent user space lookups for the same
* dentry are placed on the wait queue while the daemon
* itself is allowed passage unresticted so the create
* operation itself can then hash the dentry. Finally,
* we check for the hashed dentry and return the newly
* hashed dentry.
*/
dentry->d_op = &autofs4_root_dentry_operations;
dentry->d_fsdata = NULL;
d_instantiate(dentry, NULL);
} else {
struct autofs_info *ino = autofs4_dentry_ino(unhashed);
DPRINTK("rehash %p with %p", dentry, unhashed);
/*
* If we are racing with expire the request might not
* be quite complete but the directory has been removed
* so it must have been successful, so just wait for it.
* We need to ensure the AUTOFS_INF_EXPIRING flag is clear
* before continuing as revalidate may fail when calling
* try_to_fill_dentry (returning EAGAIN) if we don't.
*/
while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
DPRINTK("wait for incomplete expire %p name=%.*s",
unhashed, unhashed->d_name.len,
unhashed->d_name.name);
autofs4_wait(sbi, unhashed, NFY_NONE);
DPRINTK("request completed");
}
dentry = unhashed;
}
if (!oz_mode) {
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
}
if (dentry->d_op && dentry->d_op->d_revalidate) {
mutex_unlock(&dir->i_mutex);
(dentry->d_op->d_revalidate)(dentry, nd);
mutex_lock(&dir->i_mutex);
}
/*
* 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) {
/* See if we were interrupted */
if (signal_pending(current)) {
sigset_t *sigset = &current->pending.signal;
if (sigismember (sigset, SIGKILL) ||
sigismember (sigset, SIGQUIT) ||
sigismember (sigset, SIGINT)) {
if (unhashed)
dput(unhashed);
return ERR_PTR(-ERESTARTNOINTR);
}
}
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
spin_unlock(&dentry->d_lock);
}
/*
* If this dentry is unhashed, then we shouldn't honour this
* lookup. 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 (!oz_mode && d_unhashed(dentry)) {
/*
* A user space application can (and has done in the past)
* remove and re-create this directory during the callback.
* This can leave us with an unhashed dentry, but a
* successful mount! So we need to perform another
* cached lookup in case the dentry now exists.
*/
struct dentry *parent = dentry->d_parent;
struct dentry *new = d_lookup(parent, &dentry->d_name);
if (new != NULL)
dentry = new;
else
dentry = ERR_PTR(-ENOENT);
if (unhashed)
dput(unhashed);
return dentry;
}
if (unhashed)
return dentry;
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 autofs_info *p_ino;
struct inode *inode;
char *cp;
DPRINTK("%s <- %.*s", 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_add(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);
atomic_inc(&ino->count);
p_ino = autofs4_dentry_ino(dentry->d_parent);
if (p_ino && dentry->d_parent != dentry)
atomic_inc(&p_ino->count);
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 the unlink is probably the result of an expire.
* We simply d_drop it and add it to a rehash candidates list in the
* super block, which allows the dentry lookup to reuse it retaining
* the flags, such as expire in progress, in case we're racing with expire.
*
* 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 autofs4_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);
struct autofs_info *p_ino;
/* This allows root to remove symlinks */
if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
return -EACCES;
if (atomic_dec_and_test(&ino->count)) {
p_ino = autofs4_dentry_ino(dentry->d_parent);
if (p_ino && dentry->d_parent != dentry)
atomic_dec(&p_ino->count);
}
dput(ino->dentry);
dentry->d_inode->i_size = 0;
clear_nlink(dentry->d_inode);
dir->i_mtime = CURRENT_TIME;
spin_lock(&dcache_lock);
spin_lock(&sbi->rehash_lock);
list_add(&ino->rehash, &sbi->rehash_list);
spin_unlock(&sbi->rehash_lock);
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
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);
struct autofs_info *p_ino;
DPRINTK("dentry %p, removing %.*s",
dentry, dentry->d_name.len, dentry->d_name.name);
if (!autofs4_oz_mode(sbi))
return -EACCES;
spin_lock(&dcache_lock);
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&dcache_lock);
return -ENOTEMPTY;
}
spin_lock(&sbi->rehash_lock);
list_add(&ino->rehash, &sbi->rehash_list);
spin_unlock(&sbi->rehash_lock);
spin_lock(&dentry->d_lock);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
if (atomic_dec_and_test(&ino->count)) {
p_ino = autofs4_dentry_ino(dentry->d_parent);
if (p_ino && dentry->d_parent != dentry)
atomic_dec(&p_ino->count);
}
dput(ino->dentry);
dentry->d_inode->i_size = 0;
clear_nlink(dentry->d_inode);
if (dir->i_nlink)
drop_nlink(dir);
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 autofs_info *p_ino;
struct inode *inode;
if (!autofs4_oz_mode(sbi))
return -EACCES;
DPRINTK("dentry %p, creating %.*s",
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_add(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);
atomic_inc(&ino->count);
p_ino = autofs4_dentry_ino(dentry->d_parent);
if (p_ino && dentry->d_parent != dentry)
atomic_inc(&p_ino->count);
ino->inode = inode;
inc_nlink(dir);
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 __user *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 __user *p)
{
return put_user(sbi->version, p);
}
/* Return protocol sub version */
static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
{
return put_user(sbi->sub_version, p);
}
/*
* Tells the daemon whether we need to reghost or not. Also, clears
* the reghost_needed flag.
*/
static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
{
int status;
DPRINTK("returning %d", sbi->needs_reghost);
status = put_user(sbi->needs_reghost, p);
if (status)
return status;
sbi->needs_reghost = 0;
return 0;
}
/*
* Enable / Disable reghosting ioctl() operation
*/
static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
{
int status;
int val;
status = get_user(val, p);
DPRINTK("reghost = %d", val);
if (status)
return status;
/* turn on/off reghosting, with the val */
sbi->reghost_enabled = val;
return 0;
}
/*
* Tells the daemon whether it can umount the autofs mount.
*/
static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
{
int status = 0;
if (may_umount(mnt))
status = 1;
DPRINTK("returning %d", status);
status = put_user(status, p);
return status;
}
/* Identify autofs4_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);
void __user *p = (void __user *)arg;
DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
cmd,arg,sbi,task_pgrp_nr(current));
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, p);
case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
return autofs4_get_protosubver(sbi, p);
case AUTOFS_IOC_SETTIMEOUT:
return autofs4_get_set_timeout(sbi, p);
case AUTOFS_IOC_TOGGLEREGHOST:
return autofs4_toggle_reghost(sbi, p);
case AUTOFS_IOC_ASKREGHOST:
return autofs4_ask_reghost(sbi, p);
case AUTOFS_IOC_ASKUMOUNT:
return autofs4_ask_umount(filp->f_path.mnt, p);
/* return a single thing to expire */
case AUTOFS_IOC_EXPIRE:
return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
/* same as above, but can send multiple expires through pipe */
case AUTOFS_IOC_EXPIRE_MULTI:
return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
default:
return -ENOSYS;
}
}
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