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

   * Copyright © 2001-2007 Red Hat, Inc.

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

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/slab.h>
  #include <linux/mtd/mtd.h>
  #include <linux/pagemap.h>
  #include <linux/crc32.h>
  #include <linux/compiler.h>
  #include "nodelist.h"

  #include "summary.h"
  #include "debug.h"

  #define DEFAULT_EMPTY_SCAN_SIZE 256

  #define noisy_printk(noise, fmt, ...)					\
  do {									\
  	if (*(noise)) {							\
  		pr_notice(fmt, ##__VA_ARGS__);				\
  		(*(noise))--;						\
  		if (!(*(noise)))					\
  			pr_notice("Further such events for this erase block will not be printed
  "); \
  	}								\
  } while (0)

  
  static uint32_t pseudo_random;
  
  static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);

  /* These helper functions _must_ increase ofs and also do the dirty/used space accounting.

   * Returning an error will abort the mount - bad checksums etc. should just mark the space
   * as dirty.
   */

  static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);

  static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);

  
  static inline int min_free(struct jffs2_sb_info *c)
  {
  	uint32_t min = 2 * sizeof(struct jffs2_raw_inode);

  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER

  	if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
  		return c->wbuf_pagesize;
  #endif
  	return min;
  
  }

  
  static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
  	if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
  		return sector_size;
  	else
  		return DEFAULT_EMPTY_SCAN_SIZE;
  }

  static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  {

  	int ret;
  
  	if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  		return ret;
  	if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))

  		return ret;
  	/* Turned wasted size into dirty, since we apparently 
  	   think it's recoverable now. */
  	jeb->dirty_size += jeb->wasted_size;
  	c->dirty_size += jeb->wasted_size;
  	c->wasted_size -= jeb->wasted_size;
  	jeb->wasted_size = 0;
  	if (VERYDIRTY(c, jeb->dirty_size)) {
  		list_add(&jeb->list, &c->very_dirty_list);
  	} else {
  		list_add(&jeb->list, &c->dirty_list);
  	}
  	return 0;
  }

  int jffs2_scan_medium(struct jffs2_sb_info *c)
  {
  	int i, ret;
  	uint32_t empty_blocks = 0, bad_blocks = 0;
  	unsigned char *flashbuf = NULL;
  	uint32_t buf_size = 0;

  	struct jffs2_summary *s = NULL; /* summary info collected by the scan process */

  #ifndef __ECOS

  	size_t pointlen, try_size;

  	ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
  			(void **)&flashbuf, NULL);
  	if (!ret && pointlen < c->mtd->size) {
  		/* Don't muck about if it won't let us point to the whole flash */

  		jffs2_dbg(1, "MTD point returned len too short: 0x%zx
  ",
  			  pointlen);

  		mtd_unpoint(c->mtd, 0, pointlen);
  		flashbuf = NULL;

  	}

  	if (ret && ret != -EOPNOTSUPP)

  		jffs2_dbg(1, "MTD point failed %d
  ", ret);

  #endif
  	if (!flashbuf) {
  		/* For NAND it's quicker to read a whole eraseblock at a time,
  		   apparently */
  		if (jffs2_cleanmarker_oob(c))

  			try_size = c->sector_size;

  		else

  			try_size = PAGE_SIZE;

  		jffs2_dbg(1, "Trying to allocate readbuf of %zu "
  			  "bytes
  ", try_size);

  		flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);

  		if (!flashbuf)
  			return -ENOMEM;

  		jffs2_dbg(1, "Allocated readbuf of %zu bytes
  ",
  			  try_size);

  
  		buf_size = (uint32_t)try_size;

  	}

  	if (jffs2_sum_active()) {

  		s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);

  		if (!s) {
  			JFFS2_WARNING("Can't allocate memory for summary
  ");

  			ret = -ENOMEM;
  			goto out;

  		}

  	}

  	for (i=0; i<c->nr_blocks; i++) {
  		struct jffs2_eraseblock *jeb = &c->blocks[i];

  		cond_resched();

  		/* reset summary info for next eraseblock scan */
  		jffs2_sum_reset_collected(s);
  
  		ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
  						buf_size, s);

  
  		if (ret < 0)
  			goto out;

  		jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

  
  		/* Now decide which list to put it on */
  		switch(ret) {
  		case BLK_STATE_ALLFF:

  			/*
  			 * Empty block.   Since we can't be sure it

  			 * was entirely erased, we just queue it for erase
  			 * again.  It will be marked as such when the erase
  			 * is complete.  Meanwhile we still count it as empty
  			 * for later checks.
  			 */
  			empty_blocks++;
  			list_add(&jeb->list, &c->erase_pending_list);
  			c->nr_erasing_blocks++;
  			break;
  
  		case BLK_STATE_CLEANMARKER:
  			/* Only a CLEANMARKER node is valid */
  			if (!jeb->dirty_size) {
  				/* It's actually free */
  				list_add(&jeb->list, &c->free_list);
  				c->nr_free_blocks++;
  			} else {
  				/* Dirt */

  				jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list
  ",
  					  jeb->offset);

  				list_add(&jeb->list, &c->erase_pending_list);
  				c->nr_erasing_blocks++;
  			}
  			break;
  
  		case BLK_STATE_CLEAN:

  			/* Full (or almost full) of clean data. Clean list */
  			list_add(&jeb->list, &c->clean_list);

  			break;
  
  		case BLK_STATE_PARTDIRTY:

  			/* Some data, but not full. Dirty list. */
  			/* We want to remember the block with most free space
  			and stick it in the 'nextblock' position to start writing to it. */
  			if (jeb->free_size > min_free(c) &&
  					(!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
  				/* Better candidate for the next writes to go to */
  				if (c->nextblock) {

  					ret = file_dirty(c, c->nextblock);
  					if (ret)

  						goto out;

  					/* deleting summary information of the old nextblock */
  					jffs2_sum_reset_collected(c->summary);

  				}

  				/* update collected summary information for the current nextblock */

  				jffs2_sum_move_collected(c, s);

  				jffs2_dbg(1, "%s(): new nextblock = 0x%08x
  ",
  					  __func__, jeb->offset);

  				c->nextblock = jeb;
  			} else {

  				ret = file_dirty(c, jeb);
  				if (ret)

  					goto out;

  			}

  			break;
  
  		case BLK_STATE_ALLDIRTY:
  			/* Nothing valid - not even a clean marker. Needs erasing. */

  			/* For now we just put it on the erasing list. We'll start the erases later */

  			jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased
  ",

  				  jeb->offset);

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

  			c->nr_erasing_blocks++;
  			break;

  		case BLK_STATE_BADBLOCK:

  			jffs2_dbg(1, "Block at 0x%08x is bad
  ", jeb->offset);

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

  			c->bad_size += c->sector_size;
  			c->free_size -= c->sector_size;
  			bad_blocks++;
  			break;
  		default:

  			pr_warn("%s(): unknown block state
  ", __func__);

  			BUG();

  		}
  	}

  	/* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
  	if (c->nextblock && (c->nextblock->dirty_size)) {
  		c->nextblock->wasted_size += c->nextblock->dirty_size;
  		c->wasted_size += c->nextblock->dirty_size;
  		c->dirty_size -= c->nextblock->dirty_size;
  		c->nextblock->dirty_size = 0;
  	}

  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER

  	if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {

  		/* If we're going to start writing into a block which already

  		   contains data, and the end of the data isn't page-aligned,
  		   skip a little and align it. */

  		uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;

  		jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment
  ",
  			  __func__, skip);

  		jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);

  		jffs2_scan_dirty_space(c, c->nextblock, skip);

  	}
  #endif
  	if (c->nr_erasing_blocks) {

  		if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {

  			pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes
  ");
  			pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d
  ",
  				  empty_blocks, bad_blocks, c->nr_blocks);

  			ret = -EIO;
  			goto out;
  		}

  		spin_lock(&c->erase_completion_lock);
  		jffs2_garbage_collect_trigger(c);
  		spin_unlock(&c->erase_completion_lock);

  	}
  	ret = 0;
   out:
  	if (buf_size)
  		kfree(flashbuf);
  #ifndef __ECOS

  	else

  		mtd_unpoint(c->mtd, 0, c->mtd->size);

  #endif

  	kfree(s);

  	return ret;
  }

  static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
  			       uint32_t ofs, uint32_t len)

  {
  	int ret;
  	size_t retlen;
  
  	ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
  	if (ret) {

  		jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d
  ",
  			  len, ofs, ret);

  		return ret;
  	}
  	if (retlen < len) {

  		jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes
  ",
  			  ofs, retlen);

  		return -EIO;
  	}

  	return 0;
  }

  int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
  {
  	if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size

  	    && (!jeb->first_node || !ref_next(jeb->first_node)) )

  		return BLK_STATE_CLEANMARKER;
  
  	/* move blocks with max 4 byte dirty space to cleanlist */
  	else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
  		c->dirty_size -= jeb->dirty_size;
  		c->wasted_size += jeb->dirty_size;
  		jeb->wasted_size += jeb->dirty_size;
  		jeb->dirty_size = 0;
  		return BLK_STATE_CLEAN;
  	} else if (jeb->used_size || jeb->unchecked_size)
  		return BLK_STATE_PARTDIRTY;
  	else
  		return BLK_STATE_ALLDIRTY;
  }

  #ifdef CONFIG_JFFS2_FS_XATTR
  static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  				 struct jffs2_raw_xattr *rx, uint32_t ofs,
  				 struct jffs2_summary *s)
  {
  	struct jffs2_xattr_datum *xd;

  	uint32_t xid, version, totlen, crc;

  	int err;

  
  	crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
  	if (crc != je32_to_cpu(rx->node_crc)) {

  		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x
  ",
  			      ofs, je32_to_cpu(rx->node_crc), crc);

  		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
  			return err;

  		return 0;
  	}

  	xid = je32_to_cpu(rx->xid);
  	version = je32_to_cpu(rx->version);

  	totlen = PAD(sizeof(struct jffs2_raw_xattr)
  			+ rx->name_len + 1 + je16_to_cpu(rx->value_len));

  	if (totlen != je32_to_cpu(rx->totlen)) {
  		JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u
  ",
  			      ofs, je32_to_cpu(rx->totlen), totlen);

  		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
  			return err;

  		return 0;
  	}

  	xd = jffs2_setup_xattr_datum(c, xid, version);
  	if (IS_ERR(xd))

  		return PTR_ERR(xd);

  	if (xd->version > version) {
  		struct jffs2_raw_node_ref *raw
  			= jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
  		raw->next_in_ino = xd->node->next_in_ino;
  		xd->node->next_in_ino = raw;
  	} else {
  		xd->version = version;
  		xd->xprefix = rx->xprefix;
  		xd->name_len = rx->name_len;
  		xd->value_len = je16_to_cpu(rx->value_len);
  		xd->data_crc = je32_to_cpu(rx->data_crc);
  
  		jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
  	}

  	if (jffs2_sum_active())
  		jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);

  	dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)
  ",

  		  ofs, xd->xid, xd->version);
  	return 0;
  }
  
  static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
  				struct jffs2_raw_xref *rr, uint32_t ofs,
  				struct jffs2_summary *s)
  {
  	struct jffs2_xattr_ref *ref;

  	uint32_t crc;

  	int err;

  
  	crc = crc32(0, rr, sizeof(*rr) - 4);
  	if (crc != je32_to_cpu(rr->node_crc)) {

  		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x
  ",
  			      ofs, je32_to_cpu(rr->node_crc), crc);

  		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
  			return err;

  		return 0;
  	}
  
  	if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {

  		JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd
  ",

  			      ofs, je32_to_cpu(rr->totlen),
  			      PAD(sizeof(struct jffs2_raw_xref)));

  		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
  			return err;

  		return 0;
  	}
  
  	ref = jffs2_alloc_xattr_ref();
  	if (!ref)
  		return -ENOMEM;

  	/* BEFORE jffs2_build_xattr_subsystem() called, 

  	 * and AFTER xattr_ref is marked as a dead xref,

  	 * ref->xid is used to store 32bit xid, xd is not used
  	 * ref->ino is used to store 32bit inode-number, ic is not used
  	 * Thoes variables are declared as union, thus using those

  	 * are exclusive. In a similar way, ref->next is temporarily

  	 * used to chain all xattr_ref object. It's re-chained to
  	 * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
  	 */

  	ref->ino = je32_to_cpu(rr->ino);
  	ref->xid = je32_to_cpu(rr->xid);

  	ref->xseqno = je32_to_cpu(rr->xseqno);
  	if (ref->xseqno > c->highest_xseqno)
  		c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);

  	ref->next = c->xref_temp;
  	c->xref_temp = ref;

  	jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);

  	if (jffs2_sum_active())
  		jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
  	dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)
  ",
  		  ofs, ref->xid, ref->ino);
  	return 0;
  }
  #endif

  /* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
     the flash, XIP-style */

  static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {

  	struct jffs2_unknown_node *node;
  	struct jffs2_unknown_node crcnode;

  	uint32_t ofs, prevofs, max_ofs;

  	uint32_t hdr_crc, buf_ofs, buf_len;
  	int err;
  	int noise = 0;

  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER

  	int cleanmarkerfound = 0;
  #endif
  
  	ofs = jeb->offset;
  	prevofs = jeb->offset - 1;

  	jffs2_dbg(1, "%s(): Scanning block at 0x%x
  ", __func__, ofs);

  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER

  	if (jffs2_cleanmarker_oob(c)) {

  		int ret;

  		if (mtd_block_isbad(c->mtd, jeb->offset))

  			return BLK_STATE_BADBLOCK;
  
  		ret = jffs2_check_nand_cleanmarker(c, jeb);

  		jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d
  ", ret);

  		/* Even if it's not found, we still scan to see
  		   if the block is empty. We use this information
  		   to decide whether to erase it or not. */
  		switch (ret) {
  		case 0:		cleanmarkerfound = 1; break;
  		case 1: 	break;

  		default: 	return ret;
  		}
  	}
  #endif

  
  	if (jffs2_sum_active()) {

  		struct jffs2_sum_marker *sm;
  		void *sumptr = NULL;
  		uint32_t sumlen;
  	      
  		if (!buf_size) {
  			/* XIP case. Just look, point at the summary if it's there */

  			sm = (void *)buf + c->sector_size - sizeof(*sm);

  			if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
  				sumptr = buf + je32_to_cpu(sm->offset);
  				sumlen = c->sector_size - je32_to_cpu(sm->offset);
  			}
  		} else {
  			/* If NAND flash, read a whole page of it. Else just the end */
  			if (c->wbuf_pagesize)
  				buf_len = c->wbuf_pagesize;
  			else
  				buf_len = sizeof(*sm);
  
  			/* Read as much as we want into the _end_ of the preallocated buffer */
  			err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len, 
  						  jeb->offset + c->sector_size - buf_len,
  						  buf_len);				
  			if (err)
  				return err;
  
  			sm = (void *)buf + buf_size - sizeof(*sm);
  			if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
  				sumlen = c->sector_size - je32_to_cpu(sm->offset);
  				sumptr = buf + buf_size - sumlen;

  				/* sm->offset maybe wrong but MAGIC maybe right */
  				if (sumlen > c->sector_size)
  					goto full_scan;

  				/* Now, make sure the summary itself is available */
  				if (sumlen > buf_size) {
  					/* Need to kmalloc for this. */
  					sumptr = kmalloc(sumlen, GFP_KERNEL);
  					if (!sumptr)
  						return -ENOMEM;
  					memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
  				}
  				if (buf_len < sumlen) {
  					/* Need to read more so that the entire summary node is present */
  					err = jffs2_fill_scan_buf(c, sumptr, 
  								  jeb->offset + c->sector_size - sumlen,
  								  sumlen - buf_len);				
  					if (err)
  						return err;
  				}
  			}

  		}

  		if (sumptr) {
  			err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);

  			if (buf_size && sumlen > buf_size)
  				kfree(sumptr);

  			/* If it returns with a real error, bail. 
  			   If it returns positive, that's a block classification
  			   (i.e. BLK_STATE_xxx) so return that too.
  			   If it returns zero, fall through to full scan. */
  			if (err)
  				return err;

  		}

  	}

  full_scan:

  	buf_ofs = jeb->offset;
  
  	if (!buf_size) {

  		/* This is the XIP case -- we're reading _directly_ from the flash chip */

  		buf_len = c->sector_size;
  	} else {

  		buf_len = EMPTY_SCAN_SIZE(c->sector_size);

  		err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
  		if (err)
  			return err;
  	}

  	/* We temporarily use 'ofs' as a pointer into the buffer/jeb */
  	ofs = 0;

  	max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
  	/* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
  	while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)

  		ofs += 4;

  	if (ofs == max_ofs) {

  #ifdef CONFIG_JFFS2_FS_WRITEBUFFER

  		if (jffs2_cleanmarker_oob(c)) {
  			/* scan oob, take care of cleanmarker */
  			int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);

  			jffs2_dbg(2, "jffs2_check_oob_empty returned %d
  ",
  				  ret);

  			switch (ret) {
  			case 0:		return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
  			case 1: 	return BLK_STATE_ALLDIRTY;
  			default: 	return ret;
  			}
  		}
  #endif

  		jffs2_dbg(1, "Block at 0x%08x is empty (erased)
  ",
  			  jeb->offset);

  		if (c->cleanmarker_size == 0)
  			return BLK_STATE_CLEANMARKER;	/* don't bother with re-erase */
  		else
  			return BLK_STATE_ALLFF;	/* OK to erase if all blocks are like this */

  	}
  	if (ofs) {

  		jffs2_dbg(1, "Free space at %08x ends at %08x
  ", jeb->offset,
  			  jeb->offset + ofs);

  		if ((err = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
  			return err;

  		if ((err = jffs2_scan_dirty_space(c, jeb, ofs)))
  			return err;

  	}
  
  	/* Now ofs is a complete physical flash offset as it always was... */
  	ofs += jeb->offset;
  
  	noise = 10;

  	dbg_summary("no summary found in jeb 0x%08x. Apply original scan.
  ",jeb->offset);

  scan_more:

  	while(ofs < jeb->offset + c->sector_size) {

  		jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

  		/* Make sure there are node refs available for use */

  		err = jffs2_prealloc_raw_node_refs(c, jeb, 2);

  		if (err)
  			return err;

  		cond_resched();
  
  		if (ofs & 3) {

  			pr_warn("Eep. ofs 0x%08x not word-aligned!
  ", ofs);

  			ofs = PAD(ofs);
  			continue;
  		}
  		if (ofs == prevofs) {

  			pr_warn("ofs 0x%08x has already been seen. Skipping
  ",
  				ofs);

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  		prevofs = ofs;
  
  		if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {

  			jffs2_dbg(1, "Fewer than %zd bytes left to end of block. (%x+%x<%x+%zx) Not reading
  ",
  				  sizeof(struct jffs2_unknown_node),
  				  jeb->offset, c->sector_size, ofs,
  				  sizeof(*node));

  			if ((err = jffs2_scan_dirty_space(c, jeb, (jeb->offset + c->sector_size)-ofs)))
  				return err;

  			break;
  		}
  
  		if (buf_ofs + buf_len < ofs + sizeof(*node)) {
  			buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);

  			jffs2_dbg(1, "Fewer than %zd bytes (node header) left to end of buf. Reading 0x%x at 0x%08x
  ",
  				  sizeof(struct jffs2_unknown_node),
  				  buf_len, ofs);

  			err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  			if (err)
  				return err;
  			buf_ofs = ofs;
  		}
  
  		node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];
  
  		if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
  			uint32_t inbuf_ofs;

  			uint32_t empty_start, scan_end;

  
  			empty_start = ofs;
  			ofs += 4;

  			scan_end = min_t(uint32_t, EMPTY_SCAN_SIZE(c->sector_size)/8, buf_len);

  			jffs2_dbg(1, "Found empty flash at 0x%08x
  ", ofs);

  		more_empty:
  			inbuf_ofs = ofs - buf_ofs;

  			while (inbuf_ofs < scan_end) {
  				if (unlikely(*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff)) {

  					pr_warn("Empty flash at 0x%08x ends at 0x%08x
  ",
  						empty_start, ofs);

  					if ((err = jffs2_scan_dirty_space(c, jeb, ofs-empty_start)))
  						return err;

  					goto scan_more;
  				}
  
  				inbuf_ofs+=4;
  				ofs += 4;
  			}
  			/* Ran off end. */

  			jffs2_dbg(1, "Empty flash to end of buffer at 0x%08x
  ",
  				  ofs);

  
  			/* If we're only checking the beginning of a block with a cleanmarker,
  			   bail now */

  			if (buf_ofs == jeb->offset && jeb->used_size == PAD(c->cleanmarker_size) &&

  			    c->cleanmarker_size && !jeb->dirty_size && !ref_next(jeb->first_node)) {

  				jffs2_dbg(1, "%d bytes at start of block seems clean... assuming all clean
  ",
  					  EMPTY_SCAN_SIZE(c->sector_size));

  				return BLK_STATE_CLEANMARKER;
  			}

  			if (!buf_size && (scan_end != buf_len)) {/* XIP/point case */
  				scan_end = buf_len;
  				goto more_empty;
  			}
  			

  			/* See how much more there is to read in this eraseblock... */
  			buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
  			if (!buf_len) {

  				/* No more to read. Break out of main loop without marking

  				   this range of empty space as dirty (because it's not) */

  				jffs2_dbg(1, "Empty flash at %08x runs to end of block. Treating as free_space
  ",
  					  empty_start);

  				break;
  			}

  			/* point never reaches here */
  			scan_end = buf_len;

  			jffs2_dbg(1, "Reading another 0x%x at 0x%08x
  ",
  				  buf_len, ofs);

  			err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  			if (err)
  				return err;
  			buf_ofs = ofs;
  			goto more_empty;
  		}
  
  		if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {

  			pr_warn("Magic bitmask is backwards at offset 0x%08x. Wrong endian filesystem?
  ",
  				ofs);

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  		if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {

  			jffs2_dbg(1, "Dirty bitmask at 0x%08x
  ", ofs);

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  		if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {

  			pr_warn("Old JFFS2 bitmask found at 0x%08x
  ", ofs);
  			pr_warn("You cannot use older JFFS2 filesystems with newer kernels
  ");

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  		if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
  			/* OK. We're out of possibilities. Whinge and move on */

  			noisy_printk(&noise, "%s(): Magic bitmask 0x%04x not found at 0x%08x: 0x%04x instead
  ",
  				     __func__,

  				     JFFS2_MAGIC_BITMASK, ofs,

  				     je16_to_cpu(node->magic));

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  		/* We seem to have a node of sorts. Check the CRC */
  		crcnode.magic = node->magic;
  		crcnode.nodetype = cpu_to_je16( je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
  		crcnode.totlen = node->totlen;
  		hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);
  
  		if (hdr_crc != je32_to_cpu(node->hdr_crc)) {

  			noisy_printk(&noise, "%s(): Node at 0x%08x {0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x (calculated 0x%08x)
  ",
  				     __func__,

  				     ofs, je16_to_cpu(node->magic),

  				     je16_to_cpu(node->nodetype),

  				     je32_to_cpu(node->totlen),
  				     je32_to_cpu(node->hdr_crc),
  				     hdr_crc);

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}

  		if (ofs + je32_to_cpu(node->totlen) > jeb->offset + c->sector_size) {

  			/* Eep. Node goes over the end of the erase block. */

  			pr_warn("Node at 0x%08x with length 0x%08x would run over the end of the erase block
  ",
  				ofs, je32_to_cpu(node->totlen));
  			pr_warn("Perhaps the file system was created with the wrong erase size?
  ");

  			if ((err = jffs2_scan_dirty_space(c, jeb, 4)))
  				return err;

  			ofs += 4;
  			continue;
  		}
  
  		if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
  			/* Wheee. This is an obsoleted node */

  			jffs2_dbg(2, "Node at 0x%08x is obsolete. Skipping
  ",
  				  ofs);

  			if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
  				return err;

  			ofs += PAD(je32_to_cpu(node->totlen));
  			continue;
  		}
  
  		switch(je16_to_cpu(node->nodetype)) {
  		case JFFS2_NODETYPE_INODE:
  			if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
  				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);

  				jffs2_dbg(1, "Fewer than %zd bytes (inode node) left to end of buf. Reading 0x%x at 0x%08x
  ",
  					  sizeof(struct jffs2_raw_inode),
  					  buf_len, ofs);

  				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  				if (err)
  					return err;
  				buf_ofs = ofs;
  				node = (void *)buf;
  			}

  			err = jffs2_scan_inode_node(c, jeb, (void *)node, ofs, s);

  			if (err) return err;
  			ofs += PAD(je32_to_cpu(node->totlen));
  			break;

  		case JFFS2_NODETYPE_DIRENT:
  			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
  				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);

  				jffs2_dbg(1, "Fewer than %d bytes (dirent node) left to end of buf. Reading 0x%x at 0x%08x
  ",
  					  je32_to_cpu(node->totlen), buf_len,
  					  ofs);

  				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  				if (err)
  					return err;
  				buf_ofs = ofs;
  				node = (void *)buf;
  			}

  			err = jffs2_scan_dirent_node(c, jeb, (void *)node, ofs, s);

  			if (err) return err;
  			ofs += PAD(je32_to_cpu(node->totlen));
  			break;

  #ifdef CONFIG_JFFS2_FS_XATTR
  		case JFFS2_NODETYPE_XATTR:
  			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
  				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);

  				jffs2_dbg(1, "Fewer than %d bytes (xattr node) left to end of buf. Reading 0x%x at 0x%08x
  ",
  					  je32_to_cpu(node->totlen), buf_len,
  					  ofs);

  				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  				if (err)
  					return err;
  				buf_ofs = ofs;
  				node = (void *)buf;
  			}
  			err = jffs2_scan_xattr_node(c, jeb, (void *)node, ofs, s);
  			if (err)
  				return err;
  			ofs += PAD(je32_to_cpu(node->totlen));
  			break;
  		case JFFS2_NODETYPE_XREF:
  			if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
  				buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);

  				jffs2_dbg(1, "Fewer than %d bytes (xref node) left to end of buf. Reading 0x%x at 0x%08x
  ",
  					  je32_to_cpu(node->totlen), buf_len,
  					  ofs);

  				err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
  				if (err)
  					return err;
  				buf_ofs = ofs;
  				node = (void *)buf;
  			}
  			err = jffs2_scan_xref_node(c, jeb, (void *)node, ofs, s);
  			if (err)
  				return err;
  			ofs += PAD(je32_to_cpu(node->totlen));
  			break;
  #endif	/* CONFIG_JFFS2_FS_XATTR */

  		case JFFS2_NODETYPE_CLEANMARKER:

  			jffs2_dbg(1, "CLEANMARKER node found at 0x%08x
  ", ofs);

  			if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {

  				pr_notice("CLEANMARKER node found at 0x%08x has totlen 0x%x != normal 0x%x
  ",
  					  ofs, je32_to_cpu(node->totlen),
  					  c->cleanmarker_size);

  				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
  					return err;

  				ofs += PAD(sizeof(struct jffs2_unknown_node));
  			} else if (jeb->first_node) {

  				pr_notice("CLEANMARKER node found at 0x%08x, not first node in block (0x%08x)
  ",
  					  ofs, jeb->offset);

  				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(sizeof(struct jffs2_unknown_node)))))
  					return err;

  				ofs += PAD(sizeof(struct jffs2_unknown_node));
  			} else {

  				jffs2_link_node_ref(c, jeb, ofs | REF_NORMAL, c->cleanmarker_size, NULL);

  				ofs += PAD(c->cleanmarker_size);
  			}
  			break;
  
  		case JFFS2_NODETYPE_PADDING:

  			if (jffs2_sum_active())
  				jffs2_sum_add_padding_mem(s, je32_to_cpu(node->totlen));

  			if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
  				return err;

  			ofs += PAD(je32_to_cpu(node->totlen));
  			break;
  
  		default:
  			switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
  			case JFFS2_FEATURE_ROCOMPAT:

  				pr_notice("Read-only compatible feature node (0x%04x) found at offset 0x%08x
  ",
  					  je16_to_cpu(node->nodetype), ofs);

  				c->flags |= JFFS2_SB_FLAG_RO;

  				if (!(jffs2_is_readonly(c)))
  					return -EROFS;

  				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
  					return err;

  				ofs += PAD(je32_to_cpu(node->totlen));
  				break;
  
  			case JFFS2_FEATURE_INCOMPAT:

  				pr_notice("Incompatible feature node (0x%04x) found at offset 0x%08x
  ",
  					  je16_to_cpu(node->nodetype), ofs);

  				return -EINVAL;
  
  			case JFFS2_FEATURE_RWCOMPAT_DELETE:

  				jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x
  ",
  					  je16_to_cpu(node->nodetype), ofs);

  				if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(node->totlen)))))
  					return err;

  				ofs += PAD(je32_to_cpu(node->totlen));
  				break;

  			case JFFS2_FEATURE_RWCOMPAT_COPY: {

  				jffs2_dbg(1, "Unknown but compatible feature node (0x%04x) found at offset 0x%08x
  ",
  					  je16_to_cpu(node->nodetype), ofs);

  				jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(node->totlen)), NULL);

  
  				/* We can't summarise nodes we don't grok */
  				jffs2_sum_disable_collecting(s);

  				ofs += PAD(je32_to_cpu(node->totlen));
  				break;

  				}

  			}
  		}
  	}

  	if (jffs2_sum_active()) {
  		if (PAD(s->sum_size + JFFS2_SUMMARY_FRAME_SIZE) > jeb->free_size) {

  			dbg_summary("There is not enough space for "

  				"summary information, disabling for this jeb!
  ");
  			jffs2_sum_disable_collecting(s);
  		}
  	}

  	jffs2_dbg(1, "Block at 0x%08x: free 0x%08x, dirty 0x%08x, unchecked 0x%08x, used 0x%08x, wasted 0x%08x
  ",
  		  jeb->offset, jeb->free_size, jeb->dirty_size,
  		  jeb->unchecked_size, jeb->used_size, jeb->wasted_size);

  	/* mark_node_obsolete can add to wasted !! */
  	if (jeb->wasted_size) {
  		jeb->dirty_size += jeb->wasted_size;
  		c->dirty_size += jeb->wasted_size;
  		c->wasted_size -= jeb->wasted_size;
  		jeb->wasted_size = 0;
  	}

  	return jffs2_scan_classify_jeb(c, jeb);

  }

  struct jffs2_inode_cache *jffs2_scan_make_ino_cache(struct jffs2_sb_info *c, uint32_t ino)

  {
  	struct jffs2_inode_cache *ic;
  
  	ic = jffs2_get_ino_cache(c, ino);
  	if (ic)
  		return ic;
  
  	if (ino > c->highest_ino)
  		c->highest_ino = ino;
  
  	ic = jffs2_alloc_inode_cache();
  	if (!ic) {

  		pr_notice("%s(): allocation of inode cache failed
  ", __func__);

  		return NULL;
  	}
  	memset(ic, 0, sizeof(*ic));
  
  	ic->ino = ino;
  	ic->nodes = (void *)ic;
  	jffs2_add_ino_cache(c, ic);
  	if (ino == 1)

  		ic->pino_nlink = 1;

  	return ic;
  }

  static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s)

  {

  	struct jffs2_inode_cache *ic;

  	uint32_t crc, ino = je32_to_cpu(ri->ino);

  	jffs2_dbg(1, "%s(): Node at 0x%08x
  ", __func__, ofs);

  
  	/* We do very little here now. Just check the ino# to which we should attribute

  	   this node; we can do all the CRC checking etc. later. There's a tradeoff here --

  	   we used to scan the flash once only, reading everything we want from it into
  	   memory, then building all our in-core data structures and freeing the extra
  	   information. Now we allow the first part of the mount to complete a lot quicker,

  	   but we have to go _back_ to the flash in order to finish the CRC checking, etc.

  	   Which means that the _full_ amount of time to get to proper write mode with GC
  	   operational may actually be _longer_ than before. Sucks to be me. */

  	/* Check the node CRC in any case. */
  	crc = crc32(0, ri, sizeof(*ri)-8);
  	if (crc != je32_to_cpu(ri->node_crc)) {

  		pr_notice("%s(): CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x
  ",
  			  __func__, ofs, je32_to_cpu(ri->node_crc), crc);

  		/*
  		 * We believe totlen because the CRC on the node
  		 * _header_ was OK, just the node itself failed.
  		 */
  		return jffs2_scan_dirty_space(c, jeb,
  					      PAD(je32_to_cpu(ri->totlen)));
  	}

  	ic = jffs2_get_ino_cache(c, ino);
  	if (!ic) {

  		ic = jffs2_scan_make_ino_cache(c, ino);

  		if (!ic)

  			return -ENOMEM;

  	}
  
  	/* Wheee. It worked */

  	jffs2_link_node_ref(c, jeb, ofs | REF_UNCHECKED, PAD(je32_to_cpu(ri->totlen)), ic);

  	jffs2_dbg(1, "Node is ino #%u, version %d. Range 0x%x-0x%x
  ",

  		  je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
  		  je32_to_cpu(ri->offset),

  		  je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize));

  
  	pseudo_random += je32_to_cpu(ri->version);

  	if (jffs2_sum_active()) {
  		jffs2_sum_add_inode_mem(s, ri, ofs - jeb->offset);
  	}

  	return 0;
  }

  static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

  				  struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s)

  {

  	struct jffs2_full_dirent *fd;
  	struct jffs2_inode_cache *ic;

  	uint32_t checkedlen;

  	uint32_t crc;

  	int err;

  	jffs2_dbg(1, "%s(): Node at 0x%08x
  ", __func__, ofs);

  
  	/* We don't get here unless the node is still valid, so we don't have to
  	   mask in the ACCURATE bit any more. */
  	crc = crc32(0, rd, sizeof(*rd)-8);
  
  	if (crc != je32_to_cpu(rd->node_crc)) {

  		pr_notice("%s(): Node CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x
  ",
  			  __func__, ofs, je32_to_cpu(rd->node_crc), crc);

  		/* We believe totlen because the CRC on the node _header_ was OK, just the node itself failed. */

  		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
  			return err;

  		return 0;
  	}
  
  	pseudo_random += je32_to_cpu(rd->version);

  	/* Should never happen. Did. (OLPC trac #4184)*/
  	checkedlen = strnlen(rd->name, rd->nsize);
  	if (checkedlen < rd->nsize) {

  		pr_err("Dirent at %08x has zeroes in name. Truncating to %d chars
  ",

  		       ofs, checkedlen);
  	}
  	fd = jffs2_alloc_full_dirent(checkedlen+1);

  	if (!fd) {
  		return -ENOMEM;
  	}

  	memcpy(&fd->name, rd->name, checkedlen);
  	fd->name[checkedlen] = 0;

  
  	crc = crc32(0, fd->name, rd->nsize);
  	if (crc != je32_to_cpu(rd->name_crc)) {

  		pr_notice("%s(): Name CRC failed on node at 0x%08x: Read 0x%08x, calculated 0x%08x
  ",
  			  __func__, ofs, je32_to_cpu(rd->name_crc), crc);

  		jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d
  ",
  			  fd->name, je32_to_cpu(rd->ino));

  		jffs2_free_full_dirent(fd);
  		/* FIXME: Why do we believe totlen? */
  		/* We believe totlen because the CRC on the node _header_ was OK, just the name failed. */

  		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rd->totlen)))))
  			return err;

  		return 0;
  	}

  	ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
  	if (!ic) {
  		jffs2_free_full_dirent(fd);

  		return -ENOMEM;
  	}

  	fd->raw = jffs2_link_node_ref(c, jeb, ofs | dirent_node_state(rd),
  				      PAD(je32_to_cpu(rd->totlen)), ic);

  	fd->next = NULL;
  	fd->version = je32_to_cpu(rd->version);
  	fd->ino = je32_to_cpu(rd->ino);

  	fd->nhash = full_name_hash(NULL, fd->name, checkedlen);

  	fd->type = rd->type;

  	jffs2_add_fd_to_list(c, fd, &ic->scan_dents);

  	if (jffs2_sum_active()) {
  		jffs2_sum_add_dirent_mem(s, rd, ofs - jeb->offset);
  	}

  	return 0;
  }
  
  static int count_list(struct list_head *l)
  {
  	uint32_t count = 0;
  	struct list_head *tmp;
  
  	list_for_each(tmp, l) {
  		count++;
  	}
  	return count;
  }
  
  /* Note: This breaks if list_empty(head). I don't care. You
     might, if you copy this code and use it elsewhere :) */
  static void rotate_list(struct list_head *head, uint32_t count)
  {
  	struct list_head *n = head->next;
  
  	list_del(head);
  	while(count--) {
  		n = n->next;
  	}
  	list_add(head, n);
  }
  
  void jffs2_rotate_lists(struct jffs2_sb_info *c)
  {
  	uint32_t x;
  	uint32_t rotateby;
  
  	x = count_list(&c->clean_list);
  	if (x) {
  		rotateby = pseudo_random % x;

  		rotate_list((&c->clean_list), rotateby);

  	}
  
  	x = count_list(&c->very_dirty_list);
  	if (x) {
  		rotateby = pseudo_random % x;

  		rotate_list((&c->very_dirty_list), rotateby);

  	}
  
  	x = count_list(&c->dirty_list);
  	if (x) {
  		rotateby = pseudo_random % x;

  		rotate_list((&c->dirty_list), rotateby);

  	}
  
  	x = count_list(&c->erasable_list);
  	if (x) {
  		rotateby = pseudo_random % x;

  		rotate_list((&c->erasable_list), rotateby);

  	}
  
  	if (c->nr_erasing_blocks) {
  		rotateby = pseudo_random % c->nr_erasing_blocks;

  		rotate_list((&c->erase_pending_list), rotateby);

  	}
  
  	if (c->nr_free_blocks) {
  		rotateby = pseudo_random % c->nr_free_blocks;

  		rotate_list((&c->free_list), rotateby);

  	}
  }