yaffs_fs.c

YAFFS

/*
 * YAFFS: Yet another FFS. A NAND-flash specific file system.
 * yaffs_fs.c
 *
 * Copyright (C) 2002 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This is the file system front-end to YAFFS that hooks it up to
 * the VFS.
 *
 * Special notes: 
 * >> 2.4: sb->u.generic_sbp points to the yaffs_Device associated with
 *         this superblock
 * >> 2.6: sb->s_fs_info  points to the yaffs_Device associated with this
 *         superblock
 * >> inode->u.generic_ip points to the associated yaffs_Object.
 *
 * Acknowledgements:
 * * Luc van OostenRyck for numerous patches.
 * * Nick Bane for numerous patches.
 * * Nick Bane for 2.5/2.6 integration.
 * * Andras Toth for mknod rdev issue.
 * * Michael Fischer for finding the problem with inode inconsistency.
 * * Some code bodily lifted from JFFS2.
 */

const char *yaffs_fs_c_version =
    "$Id: yaffs_fs.c,v 1.38 2005/12/15 20:27:56 charles Exp $";
extern const char *yaffs_guts_c_version;

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/smp_lock.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/interrupt.h>
#include <linux/string.h>

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))

#include <linux/statfs.h>	/* Added NCB 15-8-2003 */
#include <asm/statfs.h>
#define UnlockPage(p) unlock_page(p)
#define Page_Uptodate(page)	test_bit(PG_uptodate, &(page)->flags)

/* FIXME: use sb->s_id instead ? */
#define yaffs_devname(sb, buf)	bdevname(sb->s_bdev, buf)

#else

#include <linux/locks.h>
#define	BDEVNAME_SIZE		0
#define	yaffs_devname(sb, buf)	kdevname(sb->s_dev)

#endif

#include <asm/uaccess.h>

#include "yportenv.h"
#include "yaffs_guts.h"

unsigned yaffs_traceMask = YAFFS_TRACE_ALWAYS | YAFFS_TRACE_BAD_BLOCKS /* | 0xFFFFFFFF */; 

#include <linux/mtd/mtd.h>
#include "yaffs_mtdif.h"
#include "yaffs_mtdif2.h"

/*#define T(x) printk x */

#define yaffs_InodeToObject(iptr) ((yaffs_Object *)((iptr)->u.generic_ip))
#define yaffs_DentryToObject(dptr) yaffs_InodeToObject((dptr)->d_inode)

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
#define yaffs_SuperToDevice(sb)	((yaffs_Device *)sb->s_fs_info)
#else
#define yaffs_SuperToDevice(sb)	((yaffs_Device *)sb->u.generic_sbp)
#endif

static void yaffs_put_super(struct super_block *sb);

static ssize_t yaffs_file_write(struct file *f, const char *buf, size_t n,
				loff_t * pos);

static int yaffs_file_flush(struct file *file);

static int yaffs_sync_object(struct file *file, struct dentry *dentry,
			     int datasync);

static int yaffs_readdir(struct file *f, void *dirent, filldir_t filldir);

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode,
			struct nameidata *n);
static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry,
				   struct nameidata *n);
#else
static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode);
static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry);
#endif
static int yaffs_link(struct dentry *old_dentry, struct inode *dir,
		      struct dentry *dentry);
static int yaffs_unlink(struct inode *dir, struct dentry *dentry);
static int yaffs_symlink(struct inode *dir, struct dentry *dentry,
			 const char *symname);
static int yaffs_mkdir(struct inode *dir, struct dentry *dentry, int mode);

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode,
		       dev_t dev);
#else
static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode,
		       int dev);
#endif
static int yaffs_rename(struct inode *old_dir, struct dentry *old_dentry,
			struct inode *new_dir, struct dentry *new_dentry);
static int yaffs_setattr(struct dentry *dentry, struct iattr *attr);

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
static int yaffs_statfs(struct super_block *sb, struct kstatfs *buf);
#else
static int yaffs_statfs(struct super_block *sb, struct statfs *buf);
#endif
static void yaffs_read_inode(struct inode *inode);

static void yaffs_put_inode(struct inode *inode);
static void yaffs_delete_inode(struct inode *);
static void yaffs_clear_inode(struct inode *);

static int yaffs_readpage(struct file *file, struct page *page);
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
static int yaffs_writepage(struct page *page, struct writeback_control *wbc);
#else
static int yaffs_writepage(struct page *page);
#endif
static int yaffs_prepare_write(struct file *f, struct page *pg,
			       unsigned offset, unsigned to);
static int yaffs_commit_write(struct file *f, struct page *pg, unsigned offset,
			      unsigned to);

static int yaffs_readlink(struct dentry *dentry, char __user * buffer,
			  int buflen);
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,13))
static void *yaffs_follow_link(struct dentry *dentry, struct nameidata *nd);
#else
static int yaffs_follow_link(struct dentry *dentry, struct nameidata *nd);
#endif

static struct address_space_operations yaffs_file_address_operations = {
	.readpage = yaffs_readpage,
	.writepage = yaffs_writepage,
	.prepare_write = yaffs_prepare_write,
	.commit_write = yaffs_commit_write,
};

static struct file_operations yaffs_file_operations = {
	.read = generic_file_read,
	.write = generic_file_write,
	.mmap = generic_file_mmap,
	.flush = yaffs_file_flush,
	.fsync = yaffs_sync_object,
};

static struct inode_operations yaffs_file_inode_operations = {
	.setattr = yaffs_setattr,
};

static struct inode_operations yaffs_symlink_inode_operations = {
	.readlink = yaffs_readlink,
	.follow_link = yaffs_follow_link,
	.setattr = yaffs_setattr,
};

static struct inode_operations yaffs_dir_inode_operations = {
	.create = yaffs_create,
	.lookup = yaffs_lookup,
	.link = yaffs_link,
	.unlink = yaffs_unlink,
	.symlink = yaffs_symlink,
	.mkdir = yaffs_mkdir,
	.rmdir = yaffs_unlink,
	.mknod = yaffs_mknod,
	.rename = yaffs_rename,
	.setattr = yaffs_setattr,
};

static struct file_operations yaffs_dir_operations = {
	.read = generic_read_dir,
	.readdir = yaffs_readdir,
	.fsync = yaffs_sync_object,
};

static struct super_operations yaffs_super_ops = {
	.statfs = yaffs_statfs,
	.read_inode = yaffs_read_inode,
	.put_inode = yaffs_put_inode,
	.put_super = yaffs_put_super,
	.delete_inode = yaffs_delete_inode,
	.clear_inode = yaffs_clear_inode,
};

static void yaffs_GrossLock(yaffs_Device * dev)
{
	T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs locking\n"));

	down(&dev->grossLock);
}

static void yaffs_GrossUnlock(yaffs_Device * dev)
{
	T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs unlocking\n"));
	up(&dev->grossLock);

}

static int yaffs_readlink(struct dentry *dentry, char __user * buffer,
			  int buflen)
{
	unsigned char *alias;
	int ret;

	yaffs_Device *dev = yaffs_DentryToObject(dentry)->myDev;

	yaffs_GrossLock(dev);

	alias = yaffs_GetSymlinkAlias(yaffs_DentryToObject(dentry));

	yaffs_GrossUnlock(dev);

	if (!alias)
		return -ENOMEM;

	ret = vfs_readlink(dentry, buffer, buflen, alias);
	kfree(alias);
	return ret;
}

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,13))
static void *yaffs_follow_link(struct dentry *dentry, struct nameidata *nd)
#else
static int yaffs_follow_link(struct dentry *dentry, struct nameidata *nd)
#endif
{
	unsigned char *alias;
	int ret;
	yaffs_Device *dev = yaffs_DentryToObject(dentry)->myDev;

	yaffs_GrossLock(dev);

	alias = yaffs_GetSymlinkAlias(yaffs_DentryToObject(dentry));

	yaffs_GrossUnlock(dev);

	if (!alias)
        {
		ret = -ENOMEM;
		goto out;
        }

	ret = vfs_follow_link(nd, alias);
	kfree(alias);
out:
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,13))
	return ERR_PTR (ret);
#else
	return ret;
#endif
}

struct inode *yaffs_get_inode(struct super_block *sb, int mode, int dev,
			      yaffs_Object * obj);

/*
 * Lookup is used to find objects in the fs
 */
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))

static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry,
				   struct nameidata *n)
#else
static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry)
#endif
{
	yaffs_Object *obj;
	struct inode *inode = NULL;	/* NCB 2.5/2.6 needs NULL here */

	yaffs_Device *dev = yaffs_InodeToObject(dir)->myDev;

	yaffs_GrossLock(dev);

	T(YAFFS_TRACE_OS,
	  (KERN_DEBUG "yaffs_lookup for %d:%s\n",
	   yaffs_InodeToObject(dir)->objectId, dentry->d_name.name));

	obj =
	    yaffs_FindObjectByName(yaffs_InodeToObject(dir),
				   dentry->d_name.name);

	obj = yaffs_GetEquivalentObject(obj);	/* in case it was a hardlink */
	
	/* Can't hold gross lock when calling yaffs_get_inode() */
	yaffs_GrossUnlock(dev);

	if (obj) {
		T(YAFFS_TRACE_OS,
		  (KERN_DEBUG "yaffs_lookup found %d\n", obj->objectId));

		inode = yaffs_get_inode(dir->i_sb, obj->yst_mode, 0, obj);

		if (inode) {
			T(YAFFS_TRACE_OS,
			  (KERN_DEBUG "yaffs_loookup dentry \n"));
/* #if 0 asserted by NCB for 2.5/6 compatability - falls through to
 * d_add even if NULL inode */
#if 0
			/*dget(dentry); // try to solve directory bug */
			d_add(dentry, inode);

			/* return dentry; */
			return NULL;
#endif
		}

	} else {
		T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs_lookup not found\n"));

	}

/* added NCB for 2.5/6 compatability - forces add even if inode is
 * NULL which creates dentry hash */
	d_add(dentry, inode);

	return NULL;
	/*      return (ERR_PTR(-EIO)); */

}

/* For now put inode is just for debugging
 * Put inode is called when the inode **structure** is put.
 */
static void yaffs_put_inode(struct inode *inode)
{
	T(YAFFS_TRACE_OS,
	  ("yaffs_put_inode: ino %d, count %d\n", (int)inode->i_ino,
	   atomic_read(&inode->i_count)));

}

/* clear is called to tell the fs to release any per-inode data it holds */
static void yaffs_clear_inode(struct inode *inode)
{
	yaffs_Object *obj;
	yaffs_Device *dev;

	obj = yaffs_InodeToObject(inode);

	T(YAFFS_TRACE_OS,
	  ("yaffs_clear_inode: ino %d, count %d %s\n", (int)inode->i_ino,
	   atomic_read(&inode->i_count),
	   obj ? "object exists" : "null object"));

	if (obj) {
		dev = obj->myDev;
		yaffs_GrossLock(dev);

		/* Clear the association between the inode and
		 * the yaffs_Object.
		 */
		obj->myInode = NULL;
		inode->u.generic_ip = NULL;

		/* If the object freeing was deferred, then the real
		 * free happens now.
		 * This should fix the inode inconsistency problem.
		 */

		yaffs_HandleDeferedFree(obj);

		yaffs_GrossUnlock(dev);
	}

}

/* delete is called when the link count is zero and the inode
 * is put (ie. nobody wants to know about it anymore, time to
 * delete the file).
 * NB Must call clear_inode()
 */
static void yaffs_delete_inode(struct inode *inode)
{
	yaffs_Object *obj = yaffs_InodeToObject(inode);
	yaffs_Device *dev;

	T(YAFFS_TRACE_OS,
	  ("yaffs_delete_inode: ino %d, count %d %s\n", (int)inode->i_ino,
	   atomic_read(&inode->i_count),
	   obj ? "object exists" : "null object"));

	if (obj) {
		dev = obj->myDev;
		yaffs_GrossLock(dev);
		yaffs_DeleteFile(obj);
		yaffs_GrossUnlock(dev);
	}
#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,13))
        truncate_inode_pages (&inode->i_data, 0);
#endif
	clear_inode(inode);
}

static int yaffs_file_flush(struct file *file)
{
	yaffs_Object *obj = yaffs_DentryToObject(file->f_dentry);

	yaffs_Device *dev = obj->myDev;

	T(YAFFS_TRACE_OS,
	  (KERN_DEBUG "yaffs_file_flush object %d (%s)\n", obj->objectId,
	   obj->dirty ? "dirty" : "clean"));

	yaffs_GrossLock(dev);

	yaffs_FlushFile(obj, 1);

	yaffs_GrossUnlock(dev);

	return 0;
}

static int yaffs_readpage_nolock(struct file *f, struct page *pg)
{
	/* Lifted from jffs2 */

	yaffs_Object *obj;
	unsigned char *pg_buf;
	int ret;

	yaffs_Device *dev;

	T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs_readpage at %08x, size %08x\n",
			   (unsigned)(pg->index << PAGE_CACHE_SHIFT),
			   (unsigned)PAGE_CACHE_SIZE));

	obj = yaffs_DentryToObject(f->f_dentry);

	dev = obj->myDev;

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
	BUG_ON(!PageLocked(pg));
#else
	if (!PageLocked(pg))
		PAGE_BUG(pg);
#endif

	pg_buf = kmap(pg);
	/* FIXME: Can kmap fail? */

	yaffs_GrossLock(dev);

	ret =
	    yaffs_ReadDataFromFile(obj, pg_buf, pg->index << PAGE_CACHE_SHIFT,
				   PAGE_CACHE_SIZE);

	yaffs_GrossUnlock(dev);

	if (ret >= 0)
		ret = 0;

	if (ret) {
		ClearPageUptodate(pg);
		SetPageError(pg);
	} else {
		SetPageUptodate(pg);
		ClearPageError(pg);
	}

	flush_dcache_page(pg);
	kunmap(pg);

	T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs_readpage done\n"));
	return ret;
}

static int yaffs_readpage_unlock(struct file *f, struct page *pg)
{
	int ret = yaffs_readpage_nolock(f, pg);
	UnlockPage(pg);
	return ret;
}

static int yaffs_readpage(struct file *f, struct page *pg)
{
	return yaffs_readpage_unlock(f, pg);
}

/* writepage inspired by/stolen from smbfs */

#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
static int yaffs_writepage(struct page *page, struct writeback_control *wbc)
#else
static int yaffs_writepage(struct page *page)
#endif
{
	struct address_space *mapping = page->mapping;
	loff_t offset = (loff_t) page->index << PAGE_CACHE_SHIFT;
	struct inode *inode;
	unsigned long end_index;
	char *buffer;
	yaffs_Object *obj;
	int nWritten = 0;
	unsigned nBytes;

	if (!mapping)
		BUG();
	inode = mapping->host;
	if (!inode)
		BUG();

	if (offset > inode->i_size) {
		T(YAFFS_TRACE_OS,
		  (KERN_DEBUG
		   "yaffs_writepage at %08x, inode size = %08x!!!\n",
		   (unsigned)(page->index << PAGE_CACHE_SHIFT),
		   (unsigned)inode->i_size));
		T(YAFFS_TRACE_OS,
		  (KERN_DEBUG "                -> don't care!!\n"));
		unlock_page(page);
		return 0;
	}

	end_index = inode->i_size >> PAGE_CACHE_SHIFT;

	/* easy case */
	if (page->index < end_index) {
		nBytes = PAGE_CACHE_SIZE;
	} else {
		nBytes = inode->i_size & (PAGE_CACHE_SIZE - 1);
	}

	get_page(page);

	buffer = kmap(page);

	obj = yaffs_InodeToObject(inode);
	yaffs_GrossLock(obj->myDev);

	T(YAFFS_TRACE_OS,
	  (KERN_DEBUG "yaffs_writepage at %08x, size %08x\n",
	   (unsigned)(page->index << PAGE_CACHE_SHIFT), nBytes));
	T(YAFFS_TRACE_OS,
	  (KERN_DEBUG "writepag0: obj = %05x, ino = %05x\n",
	   (int)obj->variant.fileVariant.fileSize, (int)inode->i_size));

	nWritten =
	    yaffs_WriteDataToFile(obj, buffer, page->index << PAGE_CACHE_SHIFT,
				  nBytes, 0);

	T(YAFFS_TRACE_OS,
	  (KERN_DEBUG "writepag1: obj = %05x, ino = %05x\n",
	   (int)obj->variant.fileVariant.fileSize, (int)inode->i_size));

	yaffs_GrossUnlock(obj->myDev);

	kunmap(page);
	SetPageUptodate(page);
	UnlockPage(page);
	put_page(page);

	return (nWritten == nBytes) ? 0 : -ENOSPC;
}

static int yaffs_prepare_write(struct file *f, struct page *pg,
			       unsigned offset, unsigned to)
{

	T(YAFFS_TRACE_OS, (KERN_DEBUG "yaffs_prepair_write\n"));
	if (!Page_Uptodate(pg) && (offset || to < PAGE_CACHE_SIZE))
		return yaffs_readpage_nolock(f, pg);

	return 0;