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root/fs/autofs4/inode.c

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DEFINITIONS

This source file includes following definitions.
  1. ino_lnkfree
  2. autofs4_init_ino
  3. autofs4_free_ino
  4. autofs4_force_release
  5. autofs4_kill_sb
  6. autofs4_show_options
  7. parse_options
  8. autofs4_mkroot
  9. autofs4_fill_super
  10. autofs4_get_inode

/* -*- c -*- --------------------------------------------------------------- *
 *
 * linux/fs/autofs/inode.c
 *
 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
 *  Copyright 2005-2006 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/kernel.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/bitops.h>
#include <linux/magic.h>
#include "autofs_i.h"
#include <linux/module.h>

static void ino_lnkfree(struct autofs_info *ino)
{
        if (ino->u.symlink) {
                kfree(ino->u.symlink);
                ino->u.symlink = NULL;
        }
}

struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
                                     struct autofs_sb_info *sbi, mode_t mode)
{
        int reinit = 1;

        if (ino == NULL) {
                reinit = 0;
                ino = kmalloc(sizeof(*ino), GFP_KERNEL);
        }

        if (ino == NULL)
                return NULL;

        if (!reinit) {
                ino->flags = 0;
                ino->inode = NULL;
                ino->dentry = NULL;
                ino->size = 0;
                INIT_LIST_HEAD(&ino->active);
                INIT_LIST_HEAD(&ino->expiring);
                atomic_set(&ino->count, 0);
        }

        ino->mode = mode;
        ino->last_used = jiffies;

        ino->sbi = sbi;

        if (reinit && ino->free)
                (ino->free)(ino);

        memset(&ino->u, 0, sizeof(ino->u));

        ino->free = NULL;

        if (S_ISLNK(mode))
                ino->free = ino_lnkfree;

        return ino;
}

void autofs4_free_ino(struct autofs_info *ino)
{
        struct autofs_info *p_ino;

        if (ino->dentry) {
                ino->dentry->d_fsdata = NULL;
                if (ino->dentry->d_inode) {
                        struct dentry *parent = ino->dentry->d_parent;
                        if (atomic_dec_and_test(&ino->count)) {
                                p_ino = autofs4_dentry_ino(parent);
                                if (p_ino && parent != ino->dentry)
                                        atomic_dec(&p_ino->count);
                        }
                        dput(ino->dentry);
                }
                ino->dentry = NULL;
        }
        if (ino->free)
                (ino->free)(ino);
        kfree(ino);
}

/*
 * Deal with the infamous "Busy inodes after umount ..." message.
 *
 * Clean up the dentry tree. This happens with autofs if the user
 * space program goes away due to a SIGKILL, SIGSEGV etc.
 */
static void autofs4_force_release(struct autofs_sb_info *sbi)
{
        struct dentry *this_parent = sbi->sb->s_root;
        struct list_head *next;

        if (!sbi->sb->s_root)
                return;

        spin_lock(&dcache_lock);
repeat:
        next = this_parent->d_subdirs.next;
resume:
        while (next != &this_parent->d_subdirs) {
                struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);

                /* Negative dentry - don`t care */
                if (!simple_positive(dentry)) {
                        next = next->next;
                        continue;
                }

                if (!list_empty(&dentry->d_subdirs)) {
                        this_parent = dentry;
                        goto repeat;
                }

                next = next->next;
                spin_unlock(&dcache_lock);

                DPRINTK("dentry %p %.*s",
                        dentry, (int)dentry->d_name.len, dentry->d_name.name);

                dput(dentry);
                spin_lock(&dcache_lock);
        }

        if (this_parent != sbi->sb->s_root) {
                struct dentry *dentry = this_parent;

                next = this_parent->d_u.d_child.next;
                this_parent = this_parent->d_parent;
                spin_unlock(&dcache_lock);
                DPRINTK("parent dentry %p %.*s",
                        dentry, (int)dentry->d_name.len, dentry->d_name.name);
                dput(dentry);
                spin_lock(&dcache_lock);
                goto resume;
        }
        spin_unlock(&dcache_lock);
}

void autofs4_kill_sb(struct super_block *sb)
{
        struct autofs_sb_info *sbi = autofs4_sbi(sb);

        /*
         * In the event of a failure in get_sb_nodev the superblock
         * info is not present so nothing else has been setup, so
         * just call kill_anon_super when we are called from
         * deactivate_super.
         */
        if (!sbi)
                goto out_kill_sb;

        /* Free wait queues, close pipe */
        autofs4_catatonic_mode(sbi);

        /* Clean up and release dangling references */
        autofs4_force_release(sbi);

        sb->s_fs_info = NULL;
        kfree(sbi);

out_kill_sb:
        DPRINTK("shutting down");
        kill_anon_super(sb);
}

static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
{
        struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
        struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;

        if (!sbi)
                return 0;

        seq_printf(m, ",fd=%d", sbi->pipefd);
        if (root_inode->i_uid != 0)
                seq_printf(m, ",uid=%u", root_inode->i_uid);
        if (root_inode->i_gid != 0)
                seq_printf(m, ",gid=%u", root_inode->i_gid);
        seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
        seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
        seq_printf(m, ",minproto=%d", sbi->min_proto);
        seq_printf(m, ",maxproto=%d", sbi->max_proto);

        if (sbi->type & AUTOFS_TYPE_OFFSET)
                seq_printf(m, ",offset");
        else if (sbi->type & AUTOFS_TYPE_DIRECT)
                seq_printf(m, ",direct");
        else
                seq_printf(m, ",indirect");

        return 0;
}

static const struct super_operations autofs4_sops = {
        .statfs         = simple_statfs,
        .show_options   = autofs4_show_options,
};

enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
        Opt_indirect, Opt_direct, Opt_offset};

static const match_table_t tokens = {
        {Opt_fd, "fd=%u"},
        {Opt_uid, "uid=%u"},
        {Opt_gid, "gid=%u"},
        {Opt_pgrp, "pgrp=%u"},
        {Opt_minproto, "minproto=%u"},
        {Opt_maxproto, "maxproto=%u"},
        {Opt_indirect, "indirect"},
        {Opt_direct, "direct"},
        {Opt_offset, "offset"},
        {Opt_err, NULL}
};

static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
                pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
{
        char *p;
        substring_t args[MAX_OPT_ARGS];
        int option;

        *uid = current->uid;
        *gid = current->gid;
        *pgrp = task_pgrp_nr(current);

        *minproto = AUTOFS_MIN_PROTO_VERSION;
        *maxproto = AUTOFS_MAX_PROTO_VERSION;

        *pipefd = -1;

        if (!options)
                return 1;

        while ((p = strsep(&options, ",")) != NULL) {
                int token;
                if (!*p)
                        continue;

                token = match_token(p, tokens, args);
                switch (token) {
                case Opt_fd:
                        if (match_int(args, pipefd))
                                return 1;
                        break;
                case Opt_uid:
                        if (match_int(args, &option))
                                return 1;
                        *uid = option;
                        break;
                case Opt_gid:
                        if (match_int(args, &option))
                                return 1;
                        *gid = option;
                        break;
                case Opt_pgrp:
                        if (match_int(args, &option))
                                return 1;
                        *pgrp = option;
                        break;
                case Opt_minproto:
                        if (match_int(args, &option))
                                return 1;
                        *minproto = option;
                        break;
                case Opt_maxproto:
                        if (match_int(args, &option))
                                return 1;
                        *maxproto = option;
                        break;
                case Opt_indirect:
                        *type = AUTOFS_TYPE_INDIRECT;
                        break;
                case Opt_direct:
                        *type = AUTOFS_TYPE_DIRECT;
                        break;
                case Opt_offset:
                        *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
                        break;
                default:
                        return 1;
                }
        }
        return (*pipefd < 0);
}

static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
{
        struct autofs_info *ino;

        ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
        if (!ino)
                return NULL;

        return ino;
}

static struct dentry_operations autofs4_sb_dentry_operations = {
        .d_release      = autofs4_dentry_release,
};

int autofs4_fill_super(struct super_block *s, void *data, int silent)
{
        struct inode * root_inode;
        struct dentry * root;
        struct file * pipe;
        int pipefd;
        struct autofs_sb_info *sbi;
        struct autofs_info *ino;

        sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
        if (!sbi)
                goto fail_unlock;
        DPRINTK("starting up, sbi = %p",sbi);

        s->s_fs_info = sbi;
        sbi->magic = AUTOFS_SBI_MAGIC;
        sbi->pipefd = -1;
        sbi->pipe = NULL;
        sbi->catatonic = 1;
        sbi->exp_timeout = 0;
        sbi->oz_pgrp = task_pgrp_nr(current);
        sbi->sb = s;
        sbi->version = 0;
        sbi->sub_version = 0;
        sbi->type = 0;
        sbi->min_proto = 0;
        sbi->max_proto = 0;
        mutex_init(&sbi->wq_mutex);
        spin_lock_init(&sbi->fs_lock);
        sbi->queues = NULL;
        spin_lock_init(&sbi->lookup_lock);
        INIT_LIST_HEAD(&sbi->active_list);
        INIT_LIST_HEAD(&sbi->expiring_list);
        s->s_blocksize = 1024;
        s->s_blocksize_bits = 10;
        s->s_magic = AUTOFS_SUPER_MAGIC;
        s->s_op = &autofs4_sops;
        s->s_time_gran = 1;

        /*
         * Get the root inode and dentry, but defer checking for errors.
         */
        ino = autofs4_mkroot(sbi);
        if (!ino)
                goto fail_free;
        root_inode = autofs4_get_inode(s, ino);
        if (!root_inode)
                goto fail_ino;

        root = d_alloc_root(root_inode);
        if (!root)
                goto fail_iput;
        pipe = NULL;

        root->d_op = &autofs4_sb_dentry_operations;
        root->d_fsdata = ino;

        /* Can this call block? */
        if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
                                &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
                                &sbi->max_proto)) {
                printk("autofs: called with bogus options\n");
                goto fail_dput;
        }

        root_inode->i_fop = &autofs4_root_operations;
        root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
                        &autofs4_direct_root_inode_operations :
                        &autofs4_indirect_root_inode_operations;

        /* Couldn't this be tested earlier? */
        if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
            sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
                printk("autofs: kernel does not match daemon version "
                       "daemon (%d, %d) kernel (%d, %d)\n",
                        sbi->min_proto, sbi->max_proto,
                        AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
                goto fail_dput;
        }

        /* Establish highest kernel protocol version */
        if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
                sbi->version = AUTOFS_MAX_PROTO_VERSION;
        else
                sbi->version = sbi->max_proto;
        sbi->sub_version = AUTOFS_PROTO_SUBVERSION;

        DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
        pipe = fget(pipefd);
        
        if (!pipe) {
                printk("autofs: could not open pipe file descriptor\n");
                goto fail_dput;
        }
        if (!pipe->f_op || !pipe->f_op->write)
                goto fail_fput;
        sbi->pipe = pipe;
        sbi->pipefd = pipefd;
        sbi->catatonic = 0;

        /*
         * Success! Install the root dentry now to indicate completion.
         */
        s->s_root = root;
        return 0;
        
        /*
         * Failure ... clean up.
         */
fail_fput:
        printk("autofs: pipe file descriptor does not contain proper ops\n");
        fput(pipe);
        /* fall through */
fail_dput:
        dput(root);
        goto fail_free;
fail_iput:
        printk("autofs: get root dentry failed\n");
        iput(root_inode);
fail_ino:
        kfree(ino);
fail_free:
        kfree(sbi);
        s->s_fs_info = NULL;
fail_unlock:
        return -EINVAL;
}

struct inode *autofs4_get_inode(struct super_block *sb,
                                struct autofs_info *inf)
{
        struct inode *inode = new_inode(sb);

        if (inode == NULL)
                return NULL;

        inf->inode = inode;
        inode->i_mode = inf->mode;
        if (sb->s_root) {
                inode->i_uid = sb->s_root->d_inode->i_uid;
                inode->i_gid = sb->s_root->d_inode->i_gid;
        } else {
                inode->i_uid = 0;
                inode->i_gid = 0;
        }
        inode->i_blocks = 0;
        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;

        if (S_ISDIR(inf->mode)) {
                inode->i_nlink = 2;
                inode->i_op = &autofs4_dir_inode_operations;
                inode->i_fop = &autofs4_dir_operations;
        } else if (S_ISLNK(inf->mode)) {
                inode->i_size = inf->size;
                inode->i_op = &autofs4_symlink_inode_operations;
        }

        return inode;
}

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