Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1182 insertions, 0 deletions

diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c
new file mode 100644
index 000000000..29671e33a
--- /dev/null
+++ b/fs/jffs2/scan.c
@@ -0,0 +1,1182 @@
+/*
+ * 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\n"); \
+	}								\
+} 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\n",
+			  pointlen);
+		mtd_unpoint(c->mtd, 0, pointlen);
+		flashbuf = NULL;
+	}
+	if (ret && ret != -EOPNOTSUPP)
+		jffs2_dbg(1, "MTD point failed %d\n", 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\n", try_size);
+
+		flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
+		if (!flashbuf)
+			return -ENOMEM;
+
+		jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
+			  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\n");
+			ret = -ENOMEM;
+			goto out_buf;
+		}
+	}
+
+	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\n",
+					  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\n",
+					  __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\n",
+				  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\n", 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\n", __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\n",
+			  __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->unchecked_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\n");
+			pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
+				  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:
+	jffs2_sum_reset_collected(s);
+	kfree(s);
+ out_buf:
+	if (buf_size)
+		kfree(flashbuf);
+#ifndef __ECOS
+	else
+		mtd_unpoint(c->mtd, 0, c->mtd->size);
+#endif
+	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\n",
+			  len, ofs, ret);
+		return ret;
+	}
+	if (retlen < len) {
+		jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
+			  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\n",
+			      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\n",
+			      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)\n",
+		  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\n",
+			      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\n",
+			      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)\n",
+		  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\n", __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\n", 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) {
+						if (sumlen > buf_size)
+							kfree(sumptr);
+						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\n",
+				  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)\n",
+			  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\n", 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.\n",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!\n", ofs);
+			ofs = PAD(ofs);
+			continue;
+		}
+		if (ofs == prevofs) {
+			pr_warn("ofs 0x%08x has already been seen. Skipping\n",
+				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\n",
+				  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\n",
+				  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\n", 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\n",
+						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\n",
+				  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\n",
+					  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\n",
+					  empty_start);
+				break;
+			}
+			/* point never reaches here */
+			scan_end = buf_len;
+			jffs2_dbg(1, "Reading another 0x%x at 0x%08x\n",
+				  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?\n",
+				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\n", 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\n", ofs);
+			pr_warn("You cannot use older JFFS2 filesystems with newer kernels\n");
+			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\n",
+				     __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)\n",
+				     __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\n",
+				ofs, je32_to_cpu(node->totlen));
+			pr_warn("Perhaps the file system was created with the wrong erase size?\n");
+			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\n",
+				  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\n",
+					  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\n",
+					  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\n",
+					  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\n",
+					  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\n", 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\n",
+					  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)\n",
+					  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\n",
+					  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\n",
+					  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\n",
+					  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\n",
+					  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!\n");
+			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\n",
+		  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\n", __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\n", __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\n",
+			  __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\n",
+		  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\n", __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\n",
+			  __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\n",
+		       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, checkedlen);
+	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\n",
+			  __func__, ofs, je32_to_cpu(rd->name_crc), crc);
+		jffs2_dbg(1, "Name for which CRC failed is (now) '%s', ino #%d\n",
+			  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);
+	}
+}