linux/fs/autofs4/root.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

950 lines
24 KiB
C

/* -*- 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/slab.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 struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
static void *autofs4_follow_link(struct dentry *, struct nameidata *);
#define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
#define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
const struct file_operations autofs4_root_operations = {
.open = dcache_dir_open,
.release = dcache_dir_close,
.read = generic_read_dir,
.readdir = dcache_readdir,
.llseek = dcache_dir_lseek,
.ioctl = autofs4_root_ioctl,
};
const struct file_operations autofs4_dir_operations = {
.open = autofs4_dir_open,
.release = dcache_dir_close,
.read = generic_read_dir,
.readdir = dcache_readdir,
.llseek = dcache_dir_lseek,
};
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 void autofs4_add_active(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
spin_lock(&sbi->lookup_lock);
if (!ino->active_count) {
if (list_empty(&ino->active))
list_add(&ino->active, &sbi->active_list);
}
ino->active_count++;
spin_unlock(&sbi->lookup_lock);
}
return;
}
static void autofs4_del_active(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct autofs_info *ino = autofs4_dentry_ino(dentry);
if (ino) {
spin_lock(&sbi->lookup_lock);
ino->active_count--;
if (!ino->active_count) {
if (!list_empty(&ino->active))
list_del_init(&ino->active);
}
spin_unlock(&sbi->lookup_lock);
}
return;
}
static unsigned int autofs4_need_mount(unsigned int flags)
{
unsigned int res = 0;
if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS))
res = 1;
return res;
}
static int autofs4_dir_open(struct inode *inode, struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
DPRINTK("file=%p dentry=%p %.*s",
file, dentry, dentry->d_name.len, dentry->d_name.name);
if (autofs4_oz_mode(sbi))
goto out;
/*
* An empty directory in an autofs file system is always a
* mount point. The daemon must have failed to mount this
* during lookup so it doesn't exist. This can happen, for
* example, if user space returns an incorrect status for a
* mount request. Otherwise we're doing a readdir on the
* autofs file system so just let the libfs routines handle
* it.
*/
spin_lock(&dcache_lock);
if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
spin_unlock(&dcache_lock);
return -ENOENT;
}
spin_unlock(&dcache_lock);
out:
return dcache_dir_open(inode, file);
}
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);
int status;
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(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_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 (ino->flags & AUTOFS_INF_PENDING ||
autofs4_need_mount(flags) ||
current->link_count) {
DPRINTK("waiting for mount name=%.*s",
dentry->d_name.len, dentry->d_name.name);
spin_lock(&sbi->fs_lock);
ino->flags |= AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_lock);
status = autofs4_wait(sbi, dentry, NFY_MOUNT);
DPRINTK("mount done status=%d", status);
if (status) {
spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_lock);
return status;
}
}
/* Initialize expiry counter after successful mount */
if (ino)
ino->last_used = jiffies;
spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_lock);
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);
/*
* For an expire of a covered direct or offset mount we need
* to break out of follow_down() at the autofs mount trigger
* (d_mounted--), so we can see the expiring flag, and manage
* the blocking and following here until the expire is completed.
*/
if (oz_mode) {
spin_lock(&sbi->fs_lock);
if (ino->flags & AUTOFS_INF_EXPIRING) {
spin_unlock(&sbi->fs_lock);
/* Follow down to our covering mount. */
if (!follow_down(&nd->path))
goto done;
goto follow;
}
spin_unlock(&sbi->fs_lock);
goto done;
}
/* If an expire request is pending everyone must wait. */
autofs4_expire_wait(dentry);
/* We trigger a mount for almost all flags */
lookup_type = autofs4_need_mount(nd->flags);
spin_lock(&sbi->fs_lock);
spin_lock(&dcache_lock);
if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
spin_unlock(&dcache_lock);
spin_unlock(&sbi->fs_lock);
goto follow;
}
/*
* 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.
*/
if (ino->flags & AUTOFS_INF_PENDING ||
(!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
spin_unlock(&dcache_lock);
spin_unlock(&sbi->fs_lock);
status = try_to_fill_dentry(dentry, 0);
if (status)
goto out_error;
goto follow;
}
spin_unlock(&dcache_lock);
spin_unlock(&sbi->fs_lock);
follow:
/*
* If there is no root mount it must be an autofs
* multi-mount with no root offset so we don't need
* to follow it.
*/
if (d_mountpoint(dentry)) {
if (!autofs4_follow_mount(&nd->path)) {
status = -ENOENT;
goto out_error;
}
}
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 */
spin_lock(&sbi->fs_lock);
if (autofs4_ispending(dentry)) {
/* The daemon never causes a mount to trigger */
spin_unlock(&sbi->fs_lock);
if (oz_mode)
return 1;
/*
* If the directory has gone away due to an expire
* we have been called as ->d_revalidate() and so
* we need to return false and proceed to ->lookup().
*/
if (autofs4_expire_wait(dentry) == -EAGAIN)
return 0;
/*
* 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(&sbi->fs_lock);
/* 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) && list_empty(&dentry->d_subdirs)) {
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->lookup_lock);
if (!list_empty(&inf->active))
list_del(&inf->active);
if (!list_empty(&inf->expiring))
list_del(&inf->expiring);
spin_unlock(&sbi->lookup_lock);
}
inf->dentry = NULL;
inf->inode = NULL;
autofs4_free_ino(inf);
}
}
/* For dentries of directories in the root dir */
static const struct dentry_operations autofs4_root_dentry_operations = {
.d_revalidate = autofs4_revalidate,
.d_release = autofs4_dentry_release,
};
/* For other dentries */
static const struct dentry_operations autofs4_dentry_operations = {
.d_revalidate = autofs4_revalidate,
.d_release = autofs4_dentry_release,
};
static struct dentry *autofs4_lookup_active(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct dentry *parent = dentry->d_parent;
struct qstr *name = &dentry->d_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->lookup_lock);
head = &sbi->active_list;
list_for_each(p, head) {
struct autofs_info *ino;
struct dentry *active;
struct qstr *qstr;
ino = list_entry(p, struct autofs_info, active);
active = ino->dentry;
spin_lock(&active->d_lock);
/* Already gone? */
if (atomic_read(&active->d_count) == 0)
goto next;
qstr = &active->d_name;
if (active->d_name.hash != hash)
goto next;
if (active->d_parent != parent)
goto next;
if (qstr->len != len)
goto next;
if (memcmp(qstr->name, str, len))
goto next;
if (d_unhashed(active)) {
dget(active);
spin_unlock(&active->d_lock);
spin_unlock(&sbi->lookup_lock);
spin_unlock(&dcache_lock);
return active;
}
next:
spin_unlock(&active->d_lock);
}
spin_unlock(&sbi->lookup_lock);
spin_unlock(&dcache_lock);
return NULL;
}
static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
{
struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
struct dentry *parent = dentry->d_parent;
struct qstr *name = &dentry->d_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->lookup_lock);
head = &sbi->expiring_list;
list_for_each(p, head) {
struct autofs_info *ino;
struct dentry *expiring;
struct qstr *qstr;
ino = list_entry(p, struct autofs_info, expiring);
expiring = ino->dentry;
spin_lock(&expiring->d_lock);
/* Bad luck, we've already been dentry_iput */
if (!expiring->d_inode)
goto next;
qstr = &expiring->d_name;
if (expiring->d_name.hash != hash)
goto next;
if (expiring->d_parent != parent)
goto next;
if (qstr->len != len)
goto next;
if (memcmp(qstr->name, str, len))
goto next;
if (d_unhashed(expiring)) {
dget(expiring);
spin_unlock(&expiring->d_lock);
spin_unlock(&sbi->lookup_lock);
spin_unlock(&dcache_lock);
return expiring;
}
next:
spin_unlock(&expiring->d_lock);
}
spin_unlock(&sbi->lookup_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 autofs_info *ino;
struct dentry *expiring, *active;
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);
active = autofs4_lookup_active(dentry);
if (active) {
dentry = active;
ino = autofs4_dentry_ino(dentry);
} else {
/*
* 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;
/*
* And we need to ensure that the same dentry is used for
* all following lookup calls until it is hashed so that
* the dentry flags are persistent throughout the request.
*/
ino = autofs4_init_ino(NULL, sbi, 0555);
if (!ino)
return ERR_PTR(-ENOMEM);
dentry->d_fsdata = ino;
ino->dentry = dentry;
autofs4_add_active(dentry);
d_instantiate(dentry, NULL);
}
if (!oz_mode) {
mutex_unlock(&dir->i_mutex);
expiring = autofs4_lookup_expiring(dentry);
if (expiring) {
/*
* 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.
*/
autofs4_expire_wait(expiring);
autofs4_del_expiring(expiring);
dput(expiring);
}
spin_lock(&sbi->fs_lock);
ino->flags |= AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_lock);
if (dentry->d_op && dentry->d_op->d_revalidate)
(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 (ino->flags & AUTOFS_INF_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 (active)
dput(active);
return ERR_PTR(-ERESTARTNOINTR);
}
}
if (!oz_mode) {
spin_lock(&sbi->fs_lock);
ino->flags &= ~AUTOFS_INF_PENDING;
spin_unlock(&sbi->fs_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 (active)
dput(active);
return dentry;
}
if (active)
return active;
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)
return -ENOMEM;
autofs4_del_active(dentry);
ino->size = strlen(symname);
cp = kmalloc(ino->size + 1, GFP_KERNEL);
if (!cp) {
if (!dentry->d_fsdata)
kfree(ino);
return -ENOMEM;
}
strcpy(cp, symname);
inode = autofs4_get_inode(dir->i_sb, ino);
if (!inode) {
kfree(cp);
if (!dentry->d_fsdata)
kfree(ino);
return -ENOMEM;
}
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;
ino->u.symlink = cp;
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 expiring list in the super block,
* which allows the dentry lookup to check for an incomplete 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);
autofs4_add_expiring(dentry);
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;
}
autofs4_add_expiring(dentry);
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)
return -ENOMEM;
autofs4_del_active(dentry);
inode = autofs4_get_inode(dir->i_sb, ino);
if (!inode) {
if (!dentry->d_fsdata)
kfree(ino);
return -ENOMEM;
}
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 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_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;
}
}