/*
   * JFFS2 -- Journalling Flash File System, Version 2.
   *

   * Copyright © 2001-2007 Red Hat, Inc.

   * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>

   *
   * Created by David Woodhouse <dwmw2@infradead.org>
   *
   * For licensing information, see the file 'LICENCE' in this directory.
   *

   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/mtd/mtd.h>
  #include <linux/compiler.h>
  #include <linux/crc32.h>
  #include <linux/sched.h>
  #include <linux/pagemap.h>
  #include "nodelist.h"
  
  struct erase_priv_struct {
  	struct jffs2_eraseblock *jeb;
  	struct jffs2_sb_info *c;
  };

  #ifndef __ECOS
  static void jffs2_erase_callback(struct erase_info *);
  #endif
  static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset);
  static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);

  static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);
  
  static void jffs2_erase_block(struct jffs2_sb_info *c,
  			      struct jffs2_eraseblock *jeb)
  {
  	int ret;
  	uint32_t bad_offset;
  #ifdef __ECOS
         ret = jffs2_flash_erase(c, jeb);
         if (!ret) {

  	       jffs2_erase_succeeded(c, jeb);
  	       return;

         }
         bad_offset = jeb->offset;
  #else /* Linux */
  	struct erase_info *instr;

  	D1(printk(KERN_DEBUG "jffs2_erase_block(): erase block %#08x (range %#08x-%#08x)
  ",
  				jeb->offset, jeb->offset, jeb->offset + c->sector_size));

  	instr = kmalloc(sizeof(struct erase_info) + sizeof(struct erase_priv_struct), GFP_KERNEL);
  	if (!instr) {
  		printk(KERN_WARNING "kmalloc for struct erase_info in jffs2_erase_block failed. Refiling block for later
  ");

  		mutex_lock(&c->erase_free_sem);

  		spin_lock(&c->erase_completion_lock);

  		list_move(&jeb->list, &c->erase_pending_list);

  		c->erasing_size -= c->sector_size;
  		c->dirty_size += c->sector_size;
  		jeb->dirty_size = c->sector_size;
  		spin_unlock(&c->erase_completion_lock);

  		mutex_unlock(&c->erase_free_sem);

  		return;
  	}
  
  	memset(instr, 0, sizeof(*instr));
  
  	instr->mtd = c->mtd;
  	instr->addr = jeb->offset;
  	instr->len = c->sector_size;
  	instr->callback = jffs2_erase_callback;
  	instr->priv = (unsigned long)(&instr[1]);

  	instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;

  	((struct erase_priv_struct *)instr->priv)->jeb = jeb;
  	((struct erase_priv_struct *)instr->priv)->c = c;
  
  	ret = c->mtd->erase(c->mtd, instr);
  	if (!ret)
  		return;
  
  	bad_offset = instr->fail_addr;
  	kfree(instr);
  #endif /* __ECOS */
  
  	if (ret == -ENOMEM || ret == -EAGAIN) {
  		/* Erase failed immediately. Refile it on the list */
  		D1(printk(KERN_DEBUG "Erase at 0x%08x failed: %d. Refiling on erase_pending_list
  ", jeb->offset, ret));

  		mutex_lock(&c->erase_free_sem);

  		spin_lock(&c->erase_completion_lock);

  		list_move(&jeb->list, &c->erase_pending_list);

  		c->erasing_size -= c->sector_size;
  		c->dirty_size += c->sector_size;
  		jeb->dirty_size = c->sector_size;
  		spin_unlock(&c->erase_completion_lock);

  		mutex_unlock(&c->erase_free_sem);

  		return;
  	}

  	if (ret == -EROFS)

  		printk(KERN_WARNING "Erase at 0x%08x failed immediately: -EROFS. Is the sector locked?
  ", jeb->offset);
  	else
  		printk(KERN_WARNING "Erase at 0x%08x failed immediately: errno %d
  ", jeb->offset, ret);
  
  	jffs2_erase_failed(c, jeb, bad_offset);
  }

  int jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count)

  {
  	struct jffs2_eraseblock *jeb;

  	int work_done = 0;

  	mutex_lock(&c->erase_free_sem);

  
  	spin_lock(&c->erase_completion_lock);
  
  	while (!list_empty(&c->erase_complete_list) ||
  	       !list_empty(&c->erase_pending_list)) {
  
  		if (!list_empty(&c->erase_complete_list)) {
  			jeb = list_entry(c->erase_complete_list.next, struct jffs2_eraseblock, list);

  			list_move(&jeb->list, &c->erase_checking_list);

  			spin_unlock(&c->erase_completion_lock);

  			mutex_unlock(&c->erase_free_sem);

  			jffs2_mark_erased_block(c, jeb);

  			work_done++;

  			if (!--count) {
  				D1(printk(KERN_DEBUG "Count reached. jffs2_erase_pending_blocks leaving
  "));
  				goto done;
  			}
  
  		} else if (!list_empty(&c->erase_pending_list)) {
  			jeb = list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list);
  			D1(printk(KERN_DEBUG "Starting erase of pending block 0x%08x
  ", jeb->offset));
  			list_del(&jeb->list);
  			c->erasing_size += c->sector_size;
  			c->wasted_size -= jeb->wasted_size;
  			c->free_size -= jeb->free_size;
  			c->used_size -= jeb->used_size;
  			c->dirty_size -= jeb->dirty_size;
  			jeb->wasted_size = jeb->used_size = jeb->dirty_size = jeb->free_size = 0;

  			jffs2_free_jeb_node_refs(c, jeb);

  			list_add(&jeb->list, &c->erasing_list);
  			spin_unlock(&c->erase_completion_lock);

  			mutex_unlock(&c->erase_free_sem);

  
  			jffs2_erase_block(c, jeb);
  
  		} else {
  			BUG();
  		}
  
  		/* Be nice */

  		cond_resched();

  		mutex_lock(&c->erase_free_sem);

  		spin_lock(&c->erase_completion_lock);
  	}
  
  	spin_unlock(&c->erase_completion_lock);

  	mutex_unlock(&c->erase_free_sem);

   done:
  	D1(printk(KERN_DEBUG "jffs2_erase_pending_blocks completed
  "));

  	return work_done;

  }
  
  static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  {
  	D1(printk(KERN_DEBUG "Erase completed successfully at 0x%08x
  ", jeb->offset));

  	mutex_lock(&c->erase_free_sem);

  	spin_lock(&c->erase_completion_lock);

  	list_move_tail(&jeb->list, &c->erase_complete_list);

  	/* Wake the GC thread to mark them clean */
  	jffs2_garbage_collect_trigger(c);

  	spin_unlock(&c->erase_completion_lock);

  	mutex_unlock(&c->erase_free_sem);

  	wake_up(&c->erase_wait);

  }
  
  static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
  {
  	/* For NAND, if the failure did not occur at the device level for a
  	   specific physical page, don't bother updating the bad block table. */

  	if (jffs2_cleanmarker_oob(c) && (bad_offset != (uint32_t)MTD_FAIL_ADDR_UNKNOWN)) {

  		/* We had a device-level failure to erase.  Let's see if we've
  		   failed too many times. */
  		if (!jffs2_write_nand_badblock(c, jeb, bad_offset)) {
  			/* We'd like to give this block another try. */

  			mutex_lock(&c->erase_free_sem);

  			spin_lock(&c->erase_completion_lock);

  			list_move(&jeb->list, &c->erase_pending_list);

  			c->erasing_size -= c->sector_size;
  			c->dirty_size += c->sector_size;
  			jeb->dirty_size = c->sector_size;
  			spin_unlock(&c->erase_completion_lock);

  			mutex_unlock(&c->erase_free_sem);

  			return;
  		}
  	}

  	mutex_lock(&c->erase_free_sem);

  	spin_lock(&c->erase_completion_lock);
  	c->erasing_size -= c->sector_size;
  	c->bad_size += c->sector_size;

  	list_move(&jeb->list, &c->bad_list);

  	c->nr_erasing_blocks--;
  	spin_unlock(&c->erase_completion_lock);

  	mutex_unlock(&c->erase_free_sem);

  	wake_up(&c->erase_wait);

  }

  
  #ifndef __ECOS
  static void jffs2_erase_callback(struct erase_info *instr)
  {
  	struct erase_priv_struct *priv = (void *)instr->priv;
  
  	if(instr->state != MTD_ERASE_DONE) {

  		printk(KERN_WARNING "Erase at 0x%08llx finished, but state != MTD_ERASE_DONE. State is 0x%x instead.
  ",
  			(unsigned long long)instr->addr, instr->state);

  		jffs2_erase_failed(priv->c, priv->jeb, instr->fail_addr);
  	} else {
  		jffs2_erase_succeeded(priv->c, priv->jeb);

  	}

  	kfree(instr);
  }
  #endif /* !__ECOS */
  
  /* Hmmm. Maybe we should accept the extra space it takes and make
     this a standard doubly-linked list? */
  static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
  			struct jffs2_raw_node_ref *ref, struct jffs2_eraseblock *jeb)
  {
  	struct jffs2_inode_cache *ic = NULL;
  	struct jffs2_raw_node_ref **prev;
  
  	prev = &ref->next_in_ino;
  
  	/* Walk the inode's list once, removing any nodes from this eraseblock */
  	while (1) {
  		if (!(*prev)->next_in_ino) {

  			/* We're looking at the jffs2_inode_cache, which is

  			   at the end of the linked list. Stash it and continue
  			   from the beginning of the list */
  			ic = (struct jffs2_inode_cache *)(*prev);
  			prev = &ic->nodes;
  			continue;

  		}

  		if (SECTOR_ADDR((*prev)->flash_offset) == jeb->offset) {

  			/* It's in the block we're erasing */
  			struct jffs2_raw_node_ref *this;
  
  			this = *prev;
  			*prev = this->next_in_ino;
  			this->next_in_ino = NULL;
  
  			if (this == ref)
  				break;
  
  			continue;
  		}
  		/* Not to be deleted. Skip */
  		prev = &((*prev)->next_in_ino);
  	}
  
  	/* PARANOIA */
  	if (!ic) {

  		JFFS2_WARNING("inode_cache/xattr_datum/xattr_ref"
  			      " not found in remove_node_refs()!!
  ");

  		return;
  	}
  
  	D1(printk(KERN_DEBUG "Removed nodes in range 0x%08x-0x%08x from ino #%u
  ",
  		  jeb->offset, jeb->offset + c->sector_size, ic->ino));
  
  	D2({
  		int i=0;
  		struct jffs2_raw_node_ref *this;

  		printk(KERN_DEBUG "After remove_node_refs_from_ino_list: 
  ");

  
  		this = ic->nodes;

  		printk(KERN_DEBUG);

  		while(this) {

  			printk(KERN_CONT "0x%08x(%d)->",
  			       ref_offset(this), ref_flags(this));

  			if (++i == 5) {

  				printk(KERN_DEBUG);

  				i=0;
  			}
  			this = this->next_in_ino;
  		}

  		printk(KERN_CONT "
  ");

  	});

  	switch (ic->class) {
  #ifdef CONFIG_JFFS2_FS_XATTR
  		case RAWNODE_CLASS_XATTR_DATUM:
  			jffs2_release_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
  			break;
  		case RAWNODE_CLASS_XATTR_REF:
  			jffs2_release_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
  			break;
  #endif
  		default:

  			if (ic->nodes == (void *)ic && ic->pino_nlink == 0)

  				jffs2_del_ino_cache(c, ic);
  	}

  }

  void jffs2_free_jeb_node_refs(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)

  {

  	struct jffs2_raw_node_ref *block, *ref;

  	D1(printk(KERN_DEBUG "Freeing all node refs for eraseblock offset 0x%08x
  ", jeb->offset));

  	block = ref = jeb->first_node;
  
  	while (ref) {
  		if (ref->flash_offset == REF_LINK_NODE) {
  			ref = ref->next_in_ino;
  			jffs2_free_refblock(block);
  			block = ref;
  			continue;
  		}
  		if (ref->flash_offset != REF_EMPTY_NODE && ref->next_in_ino)

  			jffs2_remove_node_refs_from_ino_list(c, ref, jeb);
  		/* else it was a non-inode node or already removed, so don't bother */

  		ref++;

  	}

  	jeb->first_node = jeb->last_node = NULL;

  }

  static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t *bad_offset)

  {

  	void *ebuf;
  	uint32_t ofs;

  	size_t retlen;

  	int ret = -EIO;

  	if (c->mtd->point) {
  		unsigned long *wordebuf;

  		ret = c->mtd->point(c->mtd, jeb->offset, c->sector_size,
  				    &retlen, &ebuf, NULL);

  		if (ret) {
  			D1(printk(KERN_DEBUG "MTD point failed %d
  ", ret));
  			goto do_flash_read;
  		}
  		if (retlen < c->sector_size) {
  			/* Don't muck about if it won't let us point to the whole erase sector */
  			D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx
  ", retlen));

  			c->mtd->unpoint(c->mtd, jeb->offset, retlen);

  			goto do_flash_read;
  		}
  		wordebuf = ebuf-sizeof(*wordebuf);
  		retlen /= sizeof(*wordebuf);
  		do {
  		   if (*++wordebuf != ~0)
  			   break;
  		} while(--retlen);

  		c->mtd->unpoint(c->mtd, jeb->offset, c->sector_size);

  		if (retlen) {

  			printk(KERN_WARNING "Newly-erased block contained word 0x%lx at offset 0x%08tx
  ",

  			       *wordebuf, jeb->offset + c->sector_size-retlen*sizeof(*wordebuf));

  			return -EIO;
  		}

  		return 0;
  	}
   do_flash_read:

  	ebuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  	if (!ebuf) {

  		printk(KERN_WARNING "Failed to allocate page buffer for verifying erase at 0x%08x. Refiling
  ", jeb->offset);
  		return -EAGAIN;
  	}

  	D1(printk(KERN_DEBUG "Verifying erase at 0x%08x
  ", jeb->offset));

  	for (ofs = jeb->offset; ofs < jeb->offset + c->sector_size; ) {
  		uint32_t readlen = min((uint32_t)PAGE_SIZE, jeb->offset + c->sector_size - ofs);
  		int i;

  		*bad_offset = ofs;

  		ret = c->mtd->read(c->mtd, ofs, readlen, &retlen, ebuf);

  		if (ret) {
  			printk(KERN_WARNING "Read of newly-erased block at 0x%08x failed: %d. Putting on bad_list
  ", ofs, ret);

  			ret = -EIO;

  			goto fail;
  		}
  		if (retlen != readlen) {
  			printk(KERN_WARNING "Short read from newly-erased block at 0x%08x. Wanted %d, got %zd
  ", ofs, readlen, retlen);

  			ret = -EIO;

  			goto fail;
  		}
  		for (i=0; i<readlen; i += sizeof(unsigned long)) {
  			/* It's OK. We know it's properly aligned */
  			unsigned long *datum = ebuf + i;
  			if (*datum + 1) {
  				*bad_offset += i;
  				printk(KERN_WARNING "Newly-erased block contained word 0x%lx at offset 0x%08x
  ", *datum, *bad_offset);

  				ret = -EIO;

  				goto fail;

  			}

  		}

  		ofs += readlen;
  		cond_resched();

  	}

  	ret = 0;
  fail:
  	kfree(ebuf);
  	return ret;
  }

  static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  {

  	size_t retlen;
  	int ret;

  	uint32_t uninitialized_var(bad_offset);

  
  	switch (jffs2_block_check_erase(c, jeb, &bad_offset)) {
  	case -EAGAIN:	goto refile;
  	case -EIO:	goto filebad;
  	}

  	/* Write the erase complete marker */

  	D1(printk(KERN_DEBUG "Writing erased marker to block at 0x%08x
  ", jeb->offset));

  	bad_offset = jeb->offset;

  	/* Cleanmarker in oob area or no cleanmarker at all ? */
  	if (jffs2_cleanmarker_oob(c) || c->cleanmarker_size == 0) {

  		if (jffs2_cleanmarker_oob(c)) {
  			if (jffs2_write_nand_cleanmarker(c, jeb))
  				goto filebad;
  		}

  	} else {

  		struct kvec vecs[1];
  		struct jffs2_unknown_node marker = {
  			.magic =	cpu_to_je16(JFFS2_MAGIC_BITMASK),
  			.nodetype =	cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER),
  			.totlen =	cpu_to_je32(c->cleanmarker_size)
  		};

  		jffs2_prealloc_raw_node_refs(c, jeb, 1);

  		marker.hdr_crc = cpu_to_je32(crc32(0, &marker, sizeof(struct jffs2_unknown_node)-4));
  
  		vecs[0].iov_base = (unsigned char *) ▮
  		vecs[0].iov_len = sizeof(marker);
  		ret = jffs2_flash_direct_writev(c, vecs, 1, jeb->offset, &retlen);

  		if (ret || retlen != sizeof(marker)) {
  			if (ret)
  				printk(KERN_WARNING "Write clean marker to block at 0x%08x failed: %d
  ",
  				       jeb->offset, ret);
  			else
  				printk(KERN_WARNING "Short write to newly-erased block at 0x%08x: Wanted %zd, got %zd
  ",
  				       jeb->offset, sizeof(marker), retlen);

  			goto filebad;

  		}

  	}

  	/* Everything else got zeroed before the erase */
  	jeb->free_size = c->sector_size;

  	mutex_lock(&c->erase_free_sem);

  	spin_lock(&c->erase_completion_lock);

  	c->erasing_size -= c->sector_size;

  	c->free_size += c->sector_size;
  
  	/* Account for cleanmarker now, if it's in-band */
  	if (c->cleanmarker_size && !jffs2_cleanmarker_oob(c))
  		jffs2_link_node_ref(c, jeb, jeb->offset | REF_NORMAL, c->cleanmarker_size, NULL);

  	list_move_tail(&jeb->list, &c->free_list);

  	c->nr_erasing_blocks--;
  	c->nr_free_blocks++;

  
  	jffs2_dbg_acct_sanity_check_nolock(c, jeb);
  	jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

  	spin_unlock(&c->erase_completion_lock);

  	mutex_unlock(&c->erase_free_sem);

  	wake_up(&c->erase_wait);

  	return;
  
  filebad:

  	jffs2_erase_failed(c, jeb, bad_offset);
  	return;

  refile:
  	/* Stick it back on the list from whence it came and come back later */

  	mutex_lock(&c->erase_free_sem);

  	spin_lock(&c->erase_completion_lock);

  	jffs2_garbage_collect_trigger(c);

  	list_move(&jeb->list, &c->erase_complete_list);

  	spin_unlock(&c->erase_completion_lock);

  	mutex_unlock(&c->erase_free_sem);

  	return;
  }