![Thomas Gleixner](/assets/img/avatar_default.png)
JFFS2 initialize f->sem mutex as "locked" in the slab constructor which is a bug. Objects are freed with unlocked f->sem mutex. So, when they allocated again, f->sem is unlocked because the slab cache constructor is not called for them. The constructor is called only once when memory pages are allocated for objects (namely, when the slab layer allocates new slabs). So, sometimes 'struct jffs2_inode_info' are allocated with unlocked f->sem, sometimes with locked. This is a bug. Instead, initialize f->sem as unlocked in the constructor. I.e., in the "constructed" state f->sem must be unlocked. From: Keijiro Yano <keijiro_yano@yahoo.co.jp> Acked-by: Artem B. Bityutskiy <dedekind@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
381 lines
9.5 KiB
C
381 lines
9.5 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright (C) 2001-2003 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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* $Id: super.c,v 1.110 2005/11/07 11:14:42 gleixner Exp $
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*
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*/
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#include <linux/config.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/jffs2.h>
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#include <linux/pagemap.h>
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#include <linux/mtd/mtd.h>
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#include <linux/ctype.h>
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#include <linux/namei.h>
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#include "compr.h"
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#include "nodelist.h"
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static void jffs2_put_super(struct super_block *);
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static kmem_cache_t *jffs2_inode_cachep;
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static struct inode *jffs2_alloc_inode(struct super_block *sb)
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{
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struct jffs2_inode_info *ei;
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ei = (struct jffs2_inode_info *)kmem_cache_alloc(jffs2_inode_cachep, SLAB_KERNEL);
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if (!ei)
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return NULL;
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return &ei->vfs_inode;
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}
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static void jffs2_destroy_inode(struct inode *inode)
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{
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kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode));
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}
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static void jffs2_i_init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
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{
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struct jffs2_inode_info *ei = (struct jffs2_inode_info *) foo;
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if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
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SLAB_CTOR_CONSTRUCTOR) {
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init_MUTEX(&ei->sem);
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inode_init_once(&ei->vfs_inode);
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}
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}
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static int jffs2_sync_fs(struct super_block *sb, int wait)
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{
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struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
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down(&c->alloc_sem);
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jffs2_flush_wbuf_pad(c);
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up(&c->alloc_sem);
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return 0;
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}
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static struct super_operations jffs2_super_operations =
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{
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.alloc_inode = jffs2_alloc_inode,
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.destroy_inode =jffs2_destroy_inode,
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.read_inode = jffs2_read_inode,
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.put_super = jffs2_put_super,
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.write_super = jffs2_write_super,
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.statfs = jffs2_statfs,
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.remount_fs = jffs2_remount_fs,
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.clear_inode = jffs2_clear_inode,
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.dirty_inode = jffs2_dirty_inode,
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.sync_fs = jffs2_sync_fs,
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};
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static int jffs2_sb_compare(struct super_block *sb, void *data)
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{
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struct jffs2_sb_info *p = data;
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struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
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/* The superblocks are considered to be equivalent if the underlying MTD
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device is the same one */
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if (c->mtd == p->mtd) {
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D1(printk(KERN_DEBUG "jffs2_sb_compare: match on device %d (\"%s\")\n", p->mtd->index, p->mtd->name));
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return 1;
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} else {
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D1(printk(KERN_DEBUG "jffs2_sb_compare: No match, device %d (\"%s\"), device %d (\"%s\")\n",
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c->mtd->index, c->mtd->name, p->mtd->index, p->mtd->name));
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return 0;
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}
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}
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static int jffs2_sb_set(struct super_block *sb, void *data)
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{
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struct jffs2_sb_info *p = data;
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/* For persistence of NFS exports etc. we use the same s_dev
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each time we mount the device, don't just use an anonymous
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device */
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sb->s_fs_info = p;
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p->os_priv = sb;
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sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, p->mtd->index);
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return 0;
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}
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static struct super_block *jffs2_get_sb_mtd(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data, struct mtd_info *mtd)
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{
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struct super_block *sb;
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struct jffs2_sb_info *c;
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int ret;
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c = kmalloc(sizeof(*c), GFP_KERNEL);
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if (!c)
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return ERR_PTR(-ENOMEM);
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memset(c, 0, sizeof(*c));
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c->mtd = mtd;
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sb = sget(fs_type, jffs2_sb_compare, jffs2_sb_set, c);
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if (IS_ERR(sb))
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goto out_put;
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if (sb->s_root) {
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/* New mountpoint for JFFS2 which is already mounted */
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D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): Device %d (\"%s\") is already mounted\n",
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mtd->index, mtd->name));
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goto out_put;
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}
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D1(printk(KERN_DEBUG "jffs2_get_sb_mtd(): New superblock for device %d (\"%s\")\n",
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mtd->index, mtd->name));
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/* Initialize JFFS2 superblock locks, the further initialization will be
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* done later */
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init_MUTEX(&c->alloc_sem);
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init_MUTEX(&c->erase_free_sem);
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init_waitqueue_head(&c->erase_wait);
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init_waitqueue_head(&c->inocache_wq);
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spin_lock_init(&c->erase_completion_lock);
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spin_lock_init(&c->inocache_lock);
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sb->s_op = &jffs2_super_operations;
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sb->s_flags = flags | MS_NOATIME;
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ret = jffs2_do_fill_super(sb, data, (flags&MS_VERBOSE)?1:0);
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if (ret) {
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/* Failure case... */
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up_write(&sb->s_umount);
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deactivate_super(sb);
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return ERR_PTR(ret);
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}
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sb->s_flags |= MS_ACTIVE;
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return sb;
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out_put:
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kfree(c);
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put_mtd_device(mtd);
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return sb;
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}
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static struct super_block *jffs2_get_sb_mtdnr(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data, int mtdnr)
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{
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struct mtd_info *mtd;
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mtd = get_mtd_device(NULL, mtdnr);
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if (!mtd) {
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D1(printk(KERN_DEBUG "jffs2: MTD device #%u doesn't appear to exist\n", mtdnr));
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return ERR_PTR(-EINVAL);
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}
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return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
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}
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static struct super_block *jffs2_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data)
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{
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int err;
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struct nameidata nd;
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int mtdnr;
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if (!dev_name)
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return ERR_PTR(-EINVAL);
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D1(printk(KERN_DEBUG "jffs2_get_sb(): dev_name \"%s\"\n", dev_name));
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/* The preferred way of mounting in future; especially when
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CONFIG_BLK_DEV is implemented - we specify the underlying
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MTD device by number or by name, so that we don't require
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block device support to be present in the kernel. */
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/* FIXME: How to do the root fs this way? */
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if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
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/* Probably mounting without the blkdev crap */
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if (dev_name[3] == ':') {
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struct mtd_info *mtd;
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/* Mount by MTD device name */
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D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd:%%s, name \"%s\"\n", dev_name+4));
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for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
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mtd = get_mtd_device(NULL, mtdnr);
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if (mtd) {
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if (!strcmp(mtd->name, dev_name+4))
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return jffs2_get_sb_mtd(fs_type, flags, dev_name, data, mtd);
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put_mtd_device(mtd);
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}
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}
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printk(KERN_NOTICE "jffs2_get_sb(): MTD device with name \"%s\" not found.\n", dev_name+4);
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} else if (isdigit(dev_name[3])) {
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/* Mount by MTD device number name */
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char *endptr;
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mtdnr = simple_strtoul(dev_name+3, &endptr, 0);
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if (!*endptr) {
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/* It was a valid number */
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D1(printk(KERN_DEBUG "jffs2_get_sb(): mtd%%d, mtdnr %d\n", mtdnr));
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return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
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}
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}
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}
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/* Try the old way - the hack where we allowed users to mount
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/dev/mtdblock$(n) but didn't actually _use_ the blkdev */
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err = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
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D1(printk(KERN_DEBUG "jffs2_get_sb(): path_lookup() returned %d, inode %p\n",
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err, nd.dentry->d_inode));
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if (err)
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return ERR_PTR(err);
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err = -EINVAL;
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if (!S_ISBLK(nd.dentry->d_inode->i_mode))
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goto out;
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if (nd.mnt->mnt_flags & MNT_NODEV) {
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err = -EACCES;
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goto out;
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}
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if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR) {
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if (!(flags & MS_VERBOSE)) /* Yes I mean this. Strangely */
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printk(KERN_NOTICE "Attempt to mount non-MTD device \"%s\" as JFFS2\n",
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dev_name);
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goto out;
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}
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mtdnr = iminor(nd.dentry->d_inode);
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path_release(&nd);
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return jffs2_get_sb_mtdnr(fs_type, flags, dev_name, data, mtdnr);
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out:
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path_release(&nd);
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return ERR_PTR(err);
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}
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static void jffs2_put_super (struct super_block *sb)
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{
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struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
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D2(printk(KERN_DEBUG "jffs2: jffs2_put_super()\n"));
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down(&c->alloc_sem);
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jffs2_flush_wbuf_pad(c);
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up(&c->alloc_sem);
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jffs2_sum_exit(c);
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jffs2_free_ino_caches(c);
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jffs2_free_raw_node_refs(c);
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if (jffs2_blocks_use_vmalloc(c))
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vfree(c->blocks);
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else
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kfree(c->blocks);
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jffs2_flash_cleanup(c);
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kfree(c->inocache_list);
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if (c->mtd->sync)
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c->mtd->sync(c->mtd);
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D1(printk(KERN_DEBUG "jffs2_put_super returning\n"));
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}
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static void jffs2_kill_sb(struct super_block *sb)
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{
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struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);
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if (!(sb->s_flags & MS_RDONLY))
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jffs2_stop_garbage_collect_thread(c);
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generic_shutdown_super(sb);
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put_mtd_device(c->mtd);
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kfree(c);
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}
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static struct file_system_type jffs2_fs_type = {
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.owner = THIS_MODULE,
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.name = "jffs2",
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.get_sb = jffs2_get_sb,
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.kill_sb = jffs2_kill_sb,
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};
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static int __init init_jffs2_fs(void)
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{
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int ret;
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printk(KERN_INFO "JFFS2 version 2.2."
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#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
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" (NAND)"
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#endif
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#ifdef CONFIG_JFFS2_SUMMARY
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" (SUMMARY) "
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#endif
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" (C) 2001-2003 Red Hat, Inc.\n");
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jffs2_inode_cachep = kmem_cache_create("jffs2_i",
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sizeof(struct jffs2_inode_info),
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0, SLAB_RECLAIM_ACCOUNT,
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jffs2_i_init_once, NULL);
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if (!jffs2_inode_cachep) {
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printk(KERN_ERR "JFFS2 error: Failed to initialise inode cache\n");
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return -ENOMEM;
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}
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ret = jffs2_compressors_init();
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if (ret) {
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printk(KERN_ERR "JFFS2 error: Failed to initialise compressors\n");
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goto out;
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}
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ret = jffs2_create_slab_caches();
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if (ret) {
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printk(KERN_ERR "JFFS2 error: Failed to initialise slab caches\n");
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goto out_compressors;
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}
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ret = register_filesystem(&jffs2_fs_type);
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if (ret) {
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printk(KERN_ERR "JFFS2 error: Failed to register filesystem\n");
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goto out_slab;
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}
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return 0;
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out_slab:
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jffs2_destroy_slab_caches();
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out_compressors:
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jffs2_compressors_exit();
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out:
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kmem_cache_destroy(jffs2_inode_cachep);
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return ret;
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}
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static void __exit exit_jffs2_fs(void)
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{
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unregister_filesystem(&jffs2_fs_type);
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jffs2_destroy_slab_caches();
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jffs2_compressors_exit();
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kmem_cache_destroy(jffs2_inode_cachep);
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}
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module_init(init_jffs2_fs);
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module_exit(exit_jffs2_fs);
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MODULE_DESCRIPTION("The Journalling Flash File System, v2");
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MODULE_AUTHOR("Red Hat, Inc.");
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MODULE_LICENSE("GPL"); // Actually dual-licensed, but it doesn't matter for
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// the sake of this tag. It's Free Software.
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