inode-v23.c

mtd最新cvs jffs文件系统分析

/*
 * JFFS -- Journalling Flash File System, Linux implementation.
 *
 * Copyright (C) 1999, 2000  Axis Communications AB.
 *
 * Created by Finn Hakansson <[e-mail]>.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * $Id: inode-v23.c,v 1.74 2003/07/02 20:36:26 acurtis Exp $
 *
 * Ported to Linux 2.3.x and MTD:
 * Copyright (C) 2000  Alexander Larsson ([e-mail]), Cendio Systems AB
 *
 * Copyright 2000, 2001  Red Hat, Inc.
 */

/* inode.c -- Contains the code that is called from the VFS.  */

/* TODO-ALEX:
 * uid and gid are just 16 bit.
 * jffs_file_write reads from user-space pointers without xx_from_user
 * maybe other stuff do to.
 */

/* Argh. Some architectures have kernel_thread in asm/processor.h
   Some have it in unistd.h and you need to define __KERNEL_SYSCALLS__
   Pass me a baseball bat and the person responsible.
   dwmw2
*/
#define __KERNEL_SYSCALLS__
#include <linux/sched.h>
#include <linux/unistd.h>

#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/jffs.h>
#include <linux/fs.h>
#include <linux/locks.h>
#include <linux/smp_lock.h>
#include <linux/ioctl.h>
#include <linux/stat.h>
#include <linux/blkdev.h>
#include <linux/quotaops.h>
#include <linux/compatmac.h>
#include <asm/semaphore.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>

#include "jffs_fm.h"
#include "intrep.h"
#if CONFIG_JFFS_PROC_FS
#include "jffs_proc.h"
#endif

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,2)) && !defined(minor)
#define minor(x) MINOR(x)
#define major(x) MAJOR(x)
#endif

static int jffs_remove(struct inode *dir, struct dentry *dentry, int type);

static struct super_operations jffs_ops;
static struct file_operations jffs_file_operations;
static struct inode_operations jffs_file_inode_operations;
static struct file_operations jffs_dir_operations;
static struct inode_operations jffs_dir_inode_operations;
static struct address_space_operations jffs_address_operations;

kmem_cache_t     *node_cache = NULL;
kmem_cache_t     *fm_cache = NULL;

/* Called by the VFS at mount time to initialize the whole file system.  */
static struct super_block *
jffs_read_super(struct super_block *sb, void *data, int silent)
{
	kdev_t dev = sb->s_dev;
	struct inode *root_inode;
	struct jffs_control *c;

	D1(printk(KERN_NOTICE "JFFS: Trying to mount device %s.\n",
		  kdevname(dev)));

	if (major(dev) != MTD_BLOCK_MAJOR) {
		printk(KERN_WARNING "JFFS: Trying to mount a "
		       "non-mtd device.\n");
		return 0;
	}

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->u.generic_sbp = (void *) 0;
	sb->s_maxbytes = 0xFFFFFFFF;

	/* Build the file system.  */
	if (jffs_build_fs(sb) < 0) {
		goto jffs_sb_err1;
	}

	/*
	 * set up enough so that we can read an inode
	 */
	sb->s_magic = JFFS_MAGIC_SB_BITMASK;
	sb->s_op = &jffs_ops;

	root_inode = iget(sb, JFFS_MIN_INO);
	if (!root_inode)
	        goto jffs_sb_err2;

	/* Get the root directory of this file system.  */
	if (!(sb->s_root = d_alloc_root(root_inode))) {
		goto jffs_sb_err3;
	}

	c = (struct jffs_control *) sb->u.generic_sbp;

#ifdef CONFIG_JFFS_PROC_FS
	/* Set up the jffs proc file system.  */
	if (jffs_register_jffs_proc_dir(dev, c) < 0) {
		printk(KERN_WARNING "JFFS: Failed to initialize the JFFS "
			"proc file system for device %s.\n",
			kdevname(dev));
	}
#endif

	/* Set the Garbage Collection thresholds */

	/* GC if free space goes below 5% of the total size */
	c->gc_minfree_threshold = c->fmc->flash_size / 20;

	if (c->gc_minfree_threshold < c->fmc->sector_size)
		c->gc_minfree_threshold = c->fmc->sector_size;

	/* GC if dirty space exceeds 33% of the total size. */
	c->gc_maxdirty_threshold = c->fmc->flash_size / 3;

	if (c->gc_maxdirty_threshold < c->fmc->sector_size)
		c->gc_maxdirty_threshold = c->fmc->sector_size;


	c->thread_pid = kernel_thread (jffs_garbage_collect_thread, 
				        (void *) c, 
				        CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
	D1(printk(KERN_NOTICE "JFFS: GC thread pid=%d.\n", (int) c->thread_pid));

	D1(printk(KERN_NOTICE "JFFS: Successfully mounted device %s.\n",
	       kdevname(dev)));
	return sb;

jffs_sb_err3:
	iput(root_inode);
jffs_sb_err2:
	jffs_cleanup_control((struct jffs_control *)sb->u.generic_sbp);
jffs_sb_err1:
	printk(KERN_WARNING "JFFS: Failed to mount device %s.\n",
	       kdevname(dev));
	return 0;
}


/* This function is called when the file system is umounted.  */
static void
jffs_put_super(struct super_block *sb)
{
	struct jffs_control *c = (struct jffs_control *) sb->u.generic_sbp;
	D1(kdev_t dev = sb->s_dev);

	D2(printk("jffs_put_super()\n"));

#ifdef CONFIG_JFFS_PROC_FS
	jffs_unregister_jffs_proc_dir(c);
#endif

	if (c->gc_task) {
		D1(printk (KERN_NOTICE "jffs_put_super(): Telling gc thread to die.\n"));
		send_sig(SIGKILL, c->gc_task, 1);
	}
	wait_for_completion(&c->gc_thread_comp);

	D1(printk (KERN_NOTICE "jffs_put_super(): Successfully waited on thread.\n"));

	jffs_cleanup_control((struct jffs_control *)sb->u.generic_sbp);
	D1(printk(KERN_NOTICE "JFFS: Successfully unmounted device %s.\n",
	       kdevname(dev)));
}


/* This function is called when user commands like chmod, chgrp and
   chown are executed. System calls like trunc() results in a call
   to this function.  */
static int
jffs_setattr(struct dentry *dentry, struct iattr *iattr)
{
	struct inode *inode = dentry->d_inode;
	struct jffs_raw_inode raw_inode;
	struct jffs_control *c;
	struct jffs_fmcontrol *fmc;
	struct jffs_file *f;
	struct jffs_node *new_node;
	int update_all;
	int res;
	int recoverable = 0;

	if ((res = inode_change_ok(inode, iattr)))
		return res;

	c = (struct jffs_control *)inode->i_sb->u.generic_sbp;
	fmc = c->fmc;

	D3(printk (KERN_NOTICE "notify_change(): down biglock\n"));
	down(&fmc->biglock);

	f = jffs_find_file(c, inode->i_ino);

	ASSERT(if (!f) {
		printk("jffs_setattr(): Invalid inode number: %lu\n",
		       inode->i_ino);
		D3(printk (KERN_NOTICE "notify_change(): up biglock\n"));
		up(&fmc->biglock);
		return -EINVAL;
	});

	D1(printk("***jffs_setattr(): file: \"%s\", ino: %u\n",
		  f->name, f->ino));

	update_all = iattr->ia_valid & ATTR_FORCE;

	if ( (update_all || iattr->ia_valid & ATTR_SIZE)
	     && (iattr->ia_size + 128 < f->size) ) {
		/* We're shrinking the file by more than 128 bytes.
		   We'll be able to GC and recover this space, so
		   allow it to go into the reserved space. */
		recoverable = 1;
        }

	if (!(new_node = jffs_alloc_node())) {
		D(printk("jffs_setattr(): Allocation failed!\n"));
		D3(printk (KERN_NOTICE "notify_change(): up biglock\n"));
		up(&fmc->biglock);
		return -ENOMEM;
	}

	new_node->data_offset = 0;
	new_node->removed_size = 0;
	raw_inode.magic = JFFS_MAGIC_BITMASK;
	raw_inode.ino = f->ino;
	raw_inode.pino = f->pino;
	raw_inode.mode = f->mode;
	raw_inode.uid = f->uid;
	raw_inode.gid = f->gid;
	raw_inode.atime = f->atime;
	raw_inode.mtime = f->mtime;
	raw_inode.ctime = f->ctime;
	raw_inode.dsize = 0;
	raw_inode.offset = 0;
	raw_inode.rsize = 0;
	raw_inode.dsize = 0;
	raw_inode.nsize = f->nsize;
	raw_inode.nlink = f->nlink;
	raw_inode.spare = 0;
	raw_inode.rename = 0;
	raw_inode.deleted = 0;

	if (update_all || iattr->ia_valid & ATTR_MODE) {
		raw_inode.mode = iattr->ia_mode;
		inode->i_mode = iattr->ia_mode;
	}
	if (update_all || iattr->ia_valid & ATTR_UID) {
		raw_inode.uid = iattr->ia_uid;
		inode->i_uid = iattr->ia_uid;
	}
	if (update_all || iattr->ia_valid & ATTR_GID) {
		raw_inode.gid = iattr->ia_gid;
		inode->i_gid = iattr->ia_gid;
	}
	if (update_all || iattr->ia_valid & ATTR_SIZE) {
		int len;
		D1(printk("jffs_notify_change(): Changing size "
			  "to %lu bytes!\n", (long)iattr->ia_size));
		raw_inode.offset = iattr->ia_size;

		/* Calculate how many bytes need to be removed from
		   the end.  */
		if (f->size < iattr->ia_size) {
			len = 0;
		}
		else {
			len = f->size - iattr->ia_size;
		}

		raw_inode.rsize = len;

		/* The updated node will be a removal node, with
		   base at the new size and size of the nbr of bytes
		   to be removed.  */
		new_node->data_offset = iattr->ia_size;
		new_node->removed_size = len;
		inode->i_size = iattr->ia_size;
		inode->i_blocks = (inode->i_size + 511) >> 9;

		if (len) {
			invalidate_inode_pages(inode);
		}
		inode->i_ctime = CURRENT_TIME;
		inode->i_mtime = inode->i_ctime;
	}
	if (update_all || iattr->ia_valid & ATTR_ATIME) {
		raw_inode.atime = iattr->ia_atime;
		inode->i_atime = iattr->ia_atime;
	}
	if (update_all || iattr->ia_valid & ATTR_MTIME) {
		raw_inode.mtime = iattr->ia_mtime;
		inode->i_mtime = iattr->ia_mtime;
	}
	if (update_all || iattr->ia_valid & ATTR_CTIME) {
		raw_inode.ctime = iattr->ia_ctime;
		inode->i_ctime = iattr->ia_ctime;
	}

	/* Write this node to the flash.  */
	if ((res = jffs_write_node(c, new_node, &raw_inode, f->name, 0, recoverable, f)) < 0) {
		D(printk("jffs_notify_change(): The write failed!\n"));
		jffs_free_node(new_node);
		D3(printk (KERN_NOTICE "n_c(): up biglock\n"));
		up(&c->fmc->biglock);
		return res;
	}

	jffs_insert_node(c, f, &raw_inode, 0, new_node);

	mark_inode_dirty(inode);
	D3(printk (KERN_NOTICE "n_c(): up biglock\n"));
	up(&c->fmc->biglock);
	return 0;
} /* jffs_notify_change()  */


struct inode *
jffs_new_inode(const struct inode * dir, struct jffs_raw_inode *raw_inode,
	       int * err)
{
	struct super_block * sb;
	struct inode * inode;
	struct jffs_control *c;
	struct jffs_file *f;

	sb = dir->i_sb;
	inode = new_inode(sb);
	if (!inode) {
		*err = -ENOMEM;
		return NULL;
	}

	c = (struct jffs_control *)sb->u.generic_sbp;

	inode->i_ino = raw_inode->ino;
	inode->i_mode = raw_inode->mode;
	inode->i_nlink = raw_inode->nlink;
	inode->i_uid = raw_inode->uid;
	inode->i_gid = raw_inode->gid;
	inode->i_rdev = NODEV;
	inode->i_size = raw_inode->dsize;
	inode->i_atime = raw_inode->atime;
	inode->i_mtime = raw_inode->mtime;
	inode->i_ctime = raw_inode->ctime;
	inode->i_blksize = PAGE_SIZE;
	inode->i_blocks = (inode->i_size + 511) >> 9;
	inode->i_version = 0;

	f = jffs_find_file(c, raw_inode->ino);

	inode->u.generic_ip = (void *)f;
	insert_inode_hash(inode);

	return inode;
}

/* Get statistics of the file system.  */
int
jffs_statfs(struct super_block *sb, struct statfs *buf)
{
	struct jffs_control *c = (struct jffs_control *) sb->u.generic_sbp;
	struct jffs_fmcontrol *fmc = c->fmc;

	D2(printk("jffs_statfs()\n"));

	buf->f_type = JFFS_MAGIC_SB_BITMASK;
	buf->f_bsize = PAGE_CACHE_SIZE;
	buf->f_blocks = (fmc->flash_size / PAGE_CACHE_SIZE)
		       - (fmc->min_free_size / PAGE_CACHE_SIZE);
	buf->f_bfree = (jffs_free_size1(fmc) + jffs_free_size2(fmc) +
		       fmc->dirty_size - fmc->min_free_size)
			       >> PAGE_CACHE_SHIFT;
	buf->f_bavail = buf->f_bfree;

	/* Find out how many files there are in the filesystem.  */
	buf->f_files = jffs_foreach_file(c, jffs_file_count);
	buf->f_ffree = buf->f_bfree;
	/* buf->f_fsid = 0; */
	buf->f_namelen = JFFS_MAX_NAME_LEN;
	return 0;
}


/* Rename a file.  */
int
jffs_rename(struct inode *old_dir, struct dentry *old_dentry,
	    struct inode *new_dir, struct dentry *new_dentry)
{
	struct jffs_raw_inode raw_inode;
	struct jffs_control *c;
	struct jffs_file *old_dir_f;
	struct jffs_file *new_dir_f;
	struct jffs_file *del_f;
	struct jffs_file *f;
	struct jffs_node *node;
	struct inode *inode;
	int result = 0;
	__u32 rename_data = 0;

	D2(printk("***jffs_rename()\n"));

	D(printk("jffs_rename(): old_dir: 0x%p, old name: 0x%p, "
		 "new_dir: 0x%p, new name: 0x%p\n",
		 old_dir, old_dentry->d_name.name,
		 new_dir, new_dentry->d_name.name));

	c = (struct jffs_control *)old_dir->i_sb->u.generic_sbp;
	ASSERT(if (!c) {
		printk(KERN_ERR "jffs_rename(): The old_dir inode "
		       "didn't have a reference to a jffs_file struct\n");
		return -EIO;
	});

	result = -ENOTDIR;
	if (!(old_dir_f = (struct jffs_file *)old_dir->u.generic_ip)) {
		D(printk("jffs_rename(): Old dir invalid.\n"));
		goto jffs_rename_end;