fastmap.c 38.2 KB
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Richard Weinberger 已提交
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/*
 * Copyright (c) 2012 Linutronix GmbH
 * Author: Richard Weinberger <richard@nod.at>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 */

#include <linux/crc32.h>
#include "ubi.h"

/**
 * ubi_calc_fm_size - calculates the fastmap size in bytes for an UBI device.
 * @ubi: UBI device description object
 */
size_t ubi_calc_fm_size(struct ubi_device *ubi)
{
	size_t size;

	size = sizeof(struct ubi_fm_hdr) + \
		sizeof(struct ubi_fm_scan_pool) + \
		sizeof(struct ubi_fm_scan_pool) + \
		(ubi->peb_count * sizeof(struct ubi_fm_ec)) + \
		(sizeof(struct ubi_fm_eba) + \
		(ubi->peb_count * sizeof(__be32))) + \
		sizeof(struct ubi_fm_volhdr) * UBI_MAX_VOLUMES;
	return roundup(size, ubi->leb_size);
}


/**
 * new_fm_vhdr - allocate a new volume header for fastmap usage.
 * @ubi: UBI device description object
 * @vol_id: the VID of the new header
 *
 * Returns a new struct ubi_vid_hdr on success.
 * NULL indicates out of memory.
 */
static struct ubi_vid_hdr *new_fm_vhdr(struct ubi_device *ubi, int vol_id)
{
	struct ubi_vid_hdr *new;

	new = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
	if (!new)
		goto out;

	new->vol_type = UBI_VID_DYNAMIC;
	new->vol_id = cpu_to_be32(vol_id);

	/* UBI implementations without fastmap support have to delete the
	 * fastmap.
	 */
	new->compat = UBI_COMPAT_DELETE;

out:
	return new;
}

/**
 * add_aeb - create and add a attach erase block to a given list.
 * @ai: UBI attach info object
 * @list: the target list
 * @pnum: PEB number of the new attach erase block
 * @ec: erease counter of the new LEB
 * @scrub: scrub this PEB after attaching
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
static int add_aeb(struct ubi_attach_info *ai, struct list_head *list,
		   int pnum, int ec, int scrub)
{
	struct ubi_ainf_peb *aeb;

	aeb = kmem_cache_alloc(ai->aeb_slab_cache, GFP_KERNEL);
	if (!aeb)
		return -ENOMEM;

	aeb->pnum = pnum;
	aeb->ec = ec;
	aeb->lnum = -1;
	aeb->scrub = scrub;
	aeb->copy_flag = aeb->sqnum = 0;

	ai->ec_sum += aeb->ec;
	ai->ec_count++;

	if (ai->max_ec < aeb->ec)
		ai->max_ec = aeb->ec;

	if (ai->min_ec > aeb->ec)
		ai->min_ec = aeb->ec;

	list_add_tail(&aeb->u.list, list);

	return 0;
}

/**
 * add_vol - create and add a new volume to ubi_attach_info.
 * @ai: ubi_attach_info object
 * @vol_id: VID of the new volume
 * @used_ebs: number of used EBS
 * @data_pad: data padding value of the new volume
 * @vol_type: volume type
 * @last_eb_bytes: number of bytes in the last LEB
 *
 * Returns the new struct ubi_ainf_volume on success.
 * NULL indicates an error.
 */
static struct ubi_ainf_volume *add_vol(struct ubi_attach_info *ai, int vol_id,
				       int used_ebs, int data_pad, u8 vol_type,
				       int last_eb_bytes)
{
	struct ubi_ainf_volume *av;
	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;

	while (*p) {
		parent = *p;
		av = rb_entry(parent, struct ubi_ainf_volume, rb);

		if (vol_id > av->vol_id)
			p = &(*p)->rb_left;
		else if (vol_id > av->vol_id)
			p = &(*p)->rb_right;
	}

	av = kmalloc(sizeof(struct ubi_ainf_volume), GFP_KERNEL);
	if (!av)
		goto out;

	av->highest_lnum = av->leb_count = 0;
	av->vol_id = vol_id;
	av->used_ebs = used_ebs;
	av->data_pad = data_pad;
	av->last_data_size = last_eb_bytes;
	av->compat = 0;
	av->vol_type = vol_type;
	av->root = RB_ROOT;

	dbg_bld("found volume (ID %i)", vol_id);

	rb_link_node(&av->rb, parent, p);
	rb_insert_color(&av->rb, &ai->volumes);

out:
	return av;
}

/**
 * assign_aeb_to_av - assigns a SEB to a given ainf_volume and removes it
 * from it's original list.
 * @ai: ubi_attach_info object
 * @aeb: the to be assigned SEB
 * @av: target scan volume
 */
static void assign_aeb_to_av(struct ubi_attach_info *ai,
			     struct ubi_ainf_peb *aeb,
			     struct ubi_ainf_volume *av)
{
	struct ubi_ainf_peb *tmp_aeb;
	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;

	p = &av->root.rb_node;
	while (*p) {
		parent = *p;

		tmp_aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);
		if (aeb->lnum != tmp_aeb->lnum) {
			if (aeb->lnum < tmp_aeb->lnum)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;

			continue;
		} else
			break;
	}

	list_del(&aeb->u.list);
	av->leb_count++;

	rb_link_node(&aeb->u.rb, parent, p);
	rb_insert_color(&aeb->u.rb, &av->root);
}

/**
 * update_vol - inserts or updates a LEB which was found a pool.
 * @ubi: the UBI device object
 * @ai: attach info object
 * @av: the volume this LEB belongs to
 * @new_vh: the volume header derived from new_aeb
 * @new_aeb: the AEB to be examined
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
static int update_vol(struct ubi_device *ubi, struct ubi_attach_info *ai,
		      struct ubi_ainf_volume *av, struct ubi_vid_hdr *new_vh,
		      struct ubi_ainf_peb *new_aeb)
{
	struct rb_node **p = &av->root.rb_node, *parent = NULL;
	struct ubi_ainf_peb *aeb, *victim;
	int cmp_res;

	while (*p) {
		parent = *p;
		aeb = rb_entry(parent, struct ubi_ainf_peb, u.rb);

		if (be32_to_cpu(new_vh->lnum) != aeb->lnum) {
			if (be32_to_cpu(new_vh->lnum) < aeb->lnum)
				p = &(*p)->rb_left;
			else
				p = &(*p)->rb_right;

			continue;
		}

		/* This case can happen if the fastmap gets written
		 * because of a volume change (creation, deletion, ..).
		 * Then a PEB can be within the persistent EBA and the pool.
		 */
		if (aeb->pnum == new_aeb->pnum) {
			ubi_assert(aeb->lnum == new_aeb->lnum);
			kmem_cache_free(ai->aeb_slab_cache, new_aeb);

			return 0;
		}

		cmp_res = ubi_compare_lebs(ubi, aeb, new_aeb->pnum, new_vh);
		if (cmp_res < 0)
			return cmp_res;

		/* new_aeb is newer */
		if (cmp_res & 1) {
			victim = kmem_cache_alloc(ai->aeb_slab_cache,
				GFP_KERNEL);
			if (!victim)
				return -ENOMEM;

			victim->ec = aeb->ec;
			victim->pnum = aeb->pnum;
			list_add_tail(&victim->u.list, &ai->erase);

			if (av->highest_lnum == be32_to_cpu(new_vh->lnum))
				av->last_data_size = \
					be32_to_cpu(new_vh->data_size);

			dbg_bld("vol %i: AEB %i's PEB %i is the newer",
				av->vol_id, aeb->lnum, new_aeb->pnum);

			aeb->ec = new_aeb->ec;
			aeb->pnum = new_aeb->pnum;
			aeb->copy_flag = new_vh->copy_flag;
			aeb->scrub = new_aeb->scrub;
			kmem_cache_free(ai->aeb_slab_cache, new_aeb);

		/* new_aeb is older */
		} else {
			dbg_bld("vol %i: AEB %i's PEB %i is old, dropping it",
				av->vol_id, aeb->lnum, new_aeb->pnum);
			list_add_tail(&new_aeb->u.list, &ai->erase);
		}

		return 0;
	}
	/* This LEB is new, let's add it to the volume */

	if (av->highest_lnum <= be32_to_cpu(new_vh->lnum)) {
		av->highest_lnum = be32_to_cpu(new_vh->lnum);
		av->last_data_size = be32_to_cpu(new_vh->data_size);
	}

	if (av->vol_type == UBI_STATIC_VOLUME)
		av->used_ebs = be32_to_cpu(new_vh->used_ebs);

	av->leb_count++;

	rb_link_node(&new_aeb->u.rb, parent, p);
	rb_insert_color(&new_aeb->u.rb, &av->root);

	return 0;
}

/**
 * process_pool_aeb - we found a non-empty PEB in a pool.
 * @ubi: UBI device object
 * @ai: attach info object
 * @new_vh: the volume header derived from new_aeb
 * @new_aeb: the AEB to be examined
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
static int process_pool_aeb(struct ubi_device *ubi, struct ubi_attach_info *ai,
			    struct ubi_vid_hdr *new_vh,
			    struct ubi_ainf_peb *new_aeb)
{
	struct ubi_ainf_volume *av, *tmp_av = NULL;
	struct rb_node **p = &ai->volumes.rb_node, *parent = NULL;
	int found = 0;

	if (be32_to_cpu(new_vh->vol_id) == UBI_FM_SB_VOLUME_ID ||
		be32_to_cpu(new_vh->vol_id) == UBI_FM_DATA_VOLUME_ID) {
		kmem_cache_free(ai->aeb_slab_cache, new_aeb);

		return 0;
	}

	/* Find the volume this SEB belongs to */
	while (*p) {
		parent = *p;
		tmp_av = rb_entry(parent, struct ubi_ainf_volume, rb);

		if (be32_to_cpu(new_vh->vol_id) > tmp_av->vol_id)
			p = &(*p)->rb_left;
		else if (be32_to_cpu(new_vh->vol_id) < tmp_av->vol_id)
			p = &(*p)->rb_right;
		else {
			found = 1;
			break;
		}
	}

	if (found)
		av = tmp_av;
	else {
		ubi_err("orphaned volume in fastmap pool!");
		return UBI_BAD_FASTMAP;
	}

	ubi_assert(be32_to_cpu(new_vh->vol_id) == av->vol_id);

	return update_vol(ubi, ai, av, new_vh, new_aeb);
}

/**
 * unmap_peb - unmap a PEB.
 * If fastmap detects a free PEB in the pool it has to check whether
 * this PEB has been unmapped after writing the fastmap.
 *
 * @ai: UBI attach info object
 * @pnum: The PEB to be unmapped
 */
static void unmap_peb(struct ubi_attach_info *ai, int pnum)
{
	struct ubi_ainf_volume *av;
	struct rb_node *node, *node2;
	struct ubi_ainf_peb *aeb;

	for (node = rb_first(&ai->volumes); node; node = rb_next(node)) {
		av = rb_entry(node, struct ubi_ainf_volume, rb);

		for (node2 = rb_first(&av->root); node2;
		     node2 = rb_next(node2)) {
			aeb = rb_entry(node2, struct ubi_ainf_peb, u.rb);
			if (aeb->pnum == pnum) {
				rb_erase(&aeb->u.rb, &av->root);
				kmem_cache_free(ai->aeb_slab_cache, aeb);
				return;
			}
		}
	}
}

/**
 * scan_pool - scans a pool for changed (no longer empty PEBs).
 * @ubi: UBI device object
 * @ai: attach info object
 * @pebs: an array of all PEB numbers in the to be scanned pool
 * @pool_size: size of the pool (number of entries in @pebs)
 * @max_sqnum: pointer to the maximal sequence number
 * @eba_orphans: list of PEBs which need to be scanned
 * @free: list of PEBs which are most likely free (and go into @ai->free)
 *
 * Returns 0 on success, if the pool is unusable UBI_BAD_FASTMAP is returned.
 * < 0 indicates an internal error.
 */
static int scan_pool(struct ubi_device *ubi, struct ubi_attach_info *ai,
		     int *pebs, int pool_size, unsigned long long *max_sqnum,
		     struct list_head *eba_orphans, struct list_head *free)
{
	struct ubi_vid_hdr *vh;
	struct ubi_ec_hdr *ech;
	struct ubi_ainf_peb *new_aeb, *tmp_aeb;
	int i, pnum, err, found_orphan, ret = 0;

	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
	if (!ech)
		return -ENOMEM;

	vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
	if (!vh) {
		kfree(ech);
		return -ENOMEM;
	}

	dbg_bld("scanning fastmap pool: size = %i", pool_size);

	/*
	 * Now scan all PEBs in the pool to find changes which have been made
	 * after the creation of the fastmap
	 */
	for (i = 0; i < pool_size; i++) {
		int scrub = 0;
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		int image_seq;
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		pnum = be32_to_cpu(pebs[i]);

		if (ubi_io_is_bad(ubi, pnum)) {
			ubi_err("bad PEB in fastmap pool!");
			ret = UBI_BAD_FASTMAP;
			goto out;
		}

		err = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
		if (err && err != UBI_IO_BITFLIPS) {
			ubi_err("unable to read EC header! PEB:%i err:%i",
				pnum, err);
			ret = err > 0 ? UBI_BAD_FASTMAP : err;
			goto out;
		} else if (ret == UBI_IO_BITFLIPS)
			scrub = 1;

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		/*
		 * Older UBI implementations have image_seq set to zero, so
		 * we shouldn't fail if image_seq == 0.
		 */
		image_seq = be32_to_cpu(ech->image_seq);

		if (image_seq && (image_seq != ubi->image_seq)) {
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			ubi_err("bad image seq: 0x%x, expected: 0x%x",
				be32_to_cpu(ech->image_seq), ubi->image_seq);
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			ret = UBI_BAD_FASTMAP;
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			goto out;
		}

		err = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
		if (err == UBI_IO_FF || err == UBI_IO_FF_BITFLIPS) {
			unsigned long long ec = be64_to_cpu(ech->ec);
			unmap_peb(ai, pnum);
			dbg_bld("Adding PEB to free: %i", pnum);
			if (err == UBI_IO_FF_BITFLIPS)
				add_aeb(ai, free, pnum, ec, 1);
			else
				add_aeb(ai, free, pnum, ec, 0);
			continue;
		} else if (err == 0 || err == UBI_IO_BITFLIPS) {
			dbg_bld("Found non empty PEB:%i in pool", pnum);

			if (err == UBI_IO_BITFLIPS)
				scrub = 1;

			found_orphan = 0;
			list_for_each_entry(tmp_aeb, eba_orphans, u.list) {
				if (tmp_aeb->pnum == pnum) {
					found_orphan = 1;
					break;
				}
			}
			if (found_orphan) {
				kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
				list_del(&tmp_aeb->u.list);
			}

			new_aeb = kmem_cache_alloc(ai->aeb_slab_cache,
						   GFP_KERNEL);
			if (!new_aeb) {
				ret = -ENOMEM;
				goto out;
			}

			new_aeb->ec = be64_to_cpu(ech->ec);
			new_aeb->pnum = pnum;
			new_aeb->lnum = be32_to_cpu(vh->lnum);
			new_aeb->sqnum = be64_to_cpu(vh->sqnum);
			new_aeb->copy_flag = vh->copy_flag;
			new_aeb->scrub = scrub;

			if (*max_sqnum < new_aeb->sqnum)
				*max_sqnum = new_aeb->sqnum;

			err = process_pool_aeb(ubi, ai, vh, new_aeb);
			if (err) {
				ret = err > 0 ? UBI_BAD_FASTMAP : err;
				goto out;
			}
		} else {
			/* We are paranoid and fall back to scanning mode */
			ubi_err("fastmap pool PEBs contains damaged PEBs!");
			ret = err > 0 ? UBI_BAD_FASTMAP : err;
			goto out;
		}

	}

out:
	ubi_free_vid_hdr(ubi, vh);
	kfree(ech);
	return ret;
}

/**
 * count_fastmap_pebs - Counts the PEBs found by fastmap.
 * @ai: The UBI attach info object
 */
static int count_fastmap_pebs(struct ubi_attach_info *ai)
{
	struct ubi_ainf_peb *aeb;
	struct ubi_ainf_volume *av;
	struct rb_node *rb1, *rb2;
	int n = 0;

	list_for_each_entry(aeb, &ai->erase, u.list)
		n++;

	list_for_each_entry(aeb, &ai->free, u.list)
		n++;

	 ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb)
		ubi_rb_for_each_entry(rb2, aeb, &av->root, u.rb)
			n++;

	return n;
}

/**
 * ubi_attach_fastmap - creates ubi_attach_info from a fastmap.
 * @ubi: UBI device object
 * @ai: UBI attach info object
 * @fm: the fastmap to be attached
 *
 * Returns 0 on success, UBI_BAD_FASTMAP if the found fastmap was unusable.
 * < 0 indicates an internal error.
 */
static int ubi_attach_fastmap(struct ubi_device *ubi,
			      struct ubi_attach_info *ai,
			      struct ubi_fastmap_layout *fm)
{
	struct list_head used, eba_orphans, free;
	struct ubi_ainf_volume *av;
	struct ubi_ainf_peb *aeb, *tmp_aeb, *_tmp_aeb;
	struct ubi_ec_hdr *ech;
	struct ubi_fm_sb *fmsb;
	struct ubi_fm_hdr *fmhdr;
	struct ubi_fm_scan_pool *fmpl1, *fmpl2;
	struct ubi_fm_ec *fmec;
	struct ubi_fm_volhdr *fmvhdr;
	struct ubi_fm_eba *fm_eba;
	int ret, i, j, pool_size, wl_pool_size;
	size_t fm_pos = 0, fm_size = ubi->fm_size;
	unsigned long long max_sqnum = 0;
	void *fm_raw = ubi->fm_buf;

	INIT_LIST_HEAD(&used);
	INIT_LIST_HEAD(&free);
	INIT_LIST_HEAD(&eba_orphans);
	INIT_LIST_HEAD(&ai->corr);
	INIT_LIST_HEAD(&ai->free);
	INIT_LIST_HEAD(&ai->erase);
	INIT_LIST_HEAD(&ai->alien);
	ai->volumes = RB_ROOT;
	ai->min_ec = UBI_MAX_ERASECOUNTER;

	ai->aeb_slab_cache = kmem_cache_create("ubi_ainf_peb_slab",
					       sizeof(struct ubi_ainf_peb),
					       0, 0, NULL);
	if (!ai->aeb_slab_cache) {
		ret = -ENOMEM;
		goto fail;
	}

	fmsb = (struct ubi_fm_sb *)(fm_raw);
	ai->max_sqnum = fmsb->sqnum;
	fm_pos += sizeof(struct ubi_fm_sb);
	if (fm_pos >= fm_size)
		goto fail_bad;

	fmhdr = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmhdr);
	if (fm_pos >= fm_size)
		goto fail_bad;

	if (be32_to_cpu(fmhdr->magic) != UBI_FM_HDR_MAGIC) {
		ubi_err("bad fastmap header magic: 0x%x, expected: 0x%x",
			be32_to_cpu(fmhdr->magic), UBI_FM_HDR_MAGIC);
		goto fail_bad;
	}

	fmpl1 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmpl1);
	if (fm_pos >= fm_size)
		goto fail_bad;
	if (be32_to_cpu(fmpl1->magic) != UBI_FM_POOL_MAGIC) {
		ubi_err("bad fastmap pool magic: 0x%x, expected: 0x%x",
			be32_to_cpu(fmpl1->magic), UBI_FM_POOL_MAGIC);
		goto fail_bad;
	}

	fmpl2 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmpl2);
	if (fm_pos >= fm_size)
		goto fail_bad;
	if (be32_to_cpu(fmpl2->magic) != UBI_FM_POOL_MAGIC) {
		ubi_err("bad fastmap pool magic: 0x%x, expected: 0x%x",
			be32_to_cpu(fmpl2->magic), UBI_FM_POOL_MAGIC);
		goto fail_bad;
	}

	pool_size = be16_to_cpu(fmpl1->size);
	wl_pool_size = be16_to_cpu(fmpl2->size);
	fm->max_pool_size = be16_to_cpu(fmpl1->max_size);
	fm->max_wl_pool_size = be16_to_cpu(fmpl2->max_size);

	if (pool_size > UBI_FM_MAX_POOL_SIZE || pool_size < 0) {
		ubi_err("bad pool size: %i", pool_size);
		goto fail_bad;
	}

	if (wl_pool_size > UBI_FM_MAX_POOL_SIZE || wl_pool_size < 0) {
		ubi_err("bad WL pool size: %i", wl_pool_size);
		goto fail_bad;
	}


	if (fm->max_pool_size > UBI_FM_MAX_POOL_SIZE ||
	    fm->max_pool_size < 0) {
		ubi_err("bad maximal pool size: %i", fm->max_pool_size);
		goto fail_bad;
	}

	if (fm->max_wl_pool_size > UBI_FM_MAX_POOL_SIZE ||
	    fm->max_wl_pool_size < 0) {
		ubi_err("bad maximal WL pool size: %i", fm->max_wl_pool_size);
		goto fail_bad;
	}

	/* read EC values from free list */
	for (i = 0; i < be32_to_cpu(fmhdr->free_peb_count); i++) {
		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fmec);
		if (fm_pos >= fm_size)
			goto fail_bad;

		add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
			be32_to_cpu(fmec->ec), 0);
	}

	/* read EC values from used list */
	for (i = 0; i < be32_to_cpu(fmhdr->used_peb_count); i++) {
		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fmec);
		if (fm_pos >= fm_size)
			goto fail_bad;

		add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
			be32_to_cpu(fmec->ec), 0);
	}

	/* read EC values from scrub list */
	for (i = 0; i < be32_to_cpu(fmhdr->scrub_peb_count); i++) {
		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fmec);
		if (fm_pos >= fm_size)
			goto fail_bad;

		add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
			be32_to_cpu(fmec->ec), 1);
	}

	/* read EC values from erase list */
	for (i = 0; i < be32_to_cpu(fmhdr->erase_peb_count); i++) {
		fmec = (struct ubi_fm_ec *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fmec);
		if (fm_pos >= fm_size)
			goto fail_bad;

		add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),
			be32_to_cpu(fmec->ec), 1);
	}

	ai->mean_ec = div_u64(ai->ec_sum, ai->ec_count);
	ai->bad_peb_count = be32_to_cpu(fmhdr->bad_peb_count);

	/* Iterate over all volumes and read their EBA table */
	for (i = 0; i < be32_to_cpu(fmhdr->vol_count); i++) {
		fmvhdr = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fmvhdr);
		if (fm_pos >= fm_size)
			goto fail_bad;

		if (be32_to_cpu(fmvhdr->magic) != UBI_FM_VHDR_MAGIC) {
			ubi_err("bad fastmap vol header magic: 0x%x, " \
				"expected: 0x%x",
				be32_to_cpu(fmvhdr->magic), UBI_FM_VHDR_MAGIC);
			goto fail_bad;
		}

		av = add_vol(ai, be32_to_cpu(fmvhdr->vol_id),
			     be32_to_cpu(fmvhdr->used_ebs),
			     be32_to_cpu(fmvhdr->data_pad),
			     fmvhdr->vol_type,
			     be32_to_cpu(fmvhdr->last_eb_bytes));

		if (!av)
			goto fail_bad;

		ai->vols_found++;
		if (ai->highest_vol_id < be32_to_cpu(fmvhdr->vol_id))
			ai->highest_vol_id = be32_to_cpu(fmvhdr->vol_id);

		fm_eba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fm_eba);
		fm_pos += (sizeof(__be32) * be32_to_cpu(fm_eba->reserved_pebs));
		if (fm_pos >= fm_size)
			goto fail_bad;

		if (be32_to_cpu(fm_eba->magic) != UBI_FM_EBA_MAGIC) {
			ubi_err("bad fastmap EBA header magic: 0x%x, " \
				"expected: 0x%x",
				be32_to_cpu(fm_eba->magic), UBI_FM_EBA_MAGIC);
			goto fail_bad;
		}

		for (j = 0; j < be32_to_cpu(fm_eba->reserved_pebs); j++) {
			int pnum = be32_to_cpu(fm_eba->pnum[j]);

			if ((int)be32_to_cpu(fm_eba->pnum[j]) < 0)
				continue;

			aeb = NULL;
			list_for_each_entry(tmp_aeb, &used, u.list) {
737
				if (tmp_aeb->pnum == pnum) {
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Richard Weinberger 已提交
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					aeb = tmp_aeb;
739 740
					break;
				}
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			}

			/* This can happen if a PEB is already in an EBA known
			 * by this fastmap but the PEB itself is not in the used
			 * list.
			 * In this case the PEB can be within the fastmap pool
			 * or while writing the fastmap it was in the protection
			 * queue.
			 */
			if (!aeb) {
				aeb = kmem_cache_alloc(ai->aeb_slab_cache,
						       GFP_KERNEL);
				if (!aeb) {
					ret = -ENOMEM;

					goto fail;
				}

				aeb->lnum = j;
				aeb->pnum = be32_to_cpu(fm_eba->pnum[j]);
				aeb->ec = -1;
				aeb->scrub = aeb->copy_flag = aeb->sqnum = 0;
				list_add_tail(&aeb->u.list, &eba_orphans);
				continue;
			}

			aeb->lnum = j;

			if (av->highest_lnum <= aeb->lnum)
				av->highest_lnum = aeb->lnum;

			assign_aeb_to_av(ai, aeb, av);

			dbg_bld("inserting PEB:%i (LEB %i) to vol %i",
				aeb->pnum, aeb->lnum, av->vol_id);
		}

		ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
		if (!ech) {
			ret = -ENOMEM;
			goto fail;
		}

		list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &eba_orphans,
					 u.list) {
			int err;

			if (ubi_io_is_bad(ubi, tmp_aeb->pnum)) {
				ubi_err("bad PEB in fastmap EBA orphan list");
				ret = UBI_BAD_FASTMAP;
				kfree(ech);
				goto fail;
			}

			err = ubi_io_read_ec_hdr(ubi, tmp_aeb->pnum, ech, 0);
			if (err && err != UBI_IO_BITFLIPS) {
				ubi_err("unable to read EC header! PEB:%i " \
					"err:%i", tmp_aeb->pnum, err);
				ret = err > 0 ? UBI_BAD_FASTMAP : err;
				kfree(ech);

				goto fail;
			} else if (err == UBI_IO_BITFLIPS)
				tmp_aeb->scrub = 1;

			tmp_aeb->ec = be64_to_cpu(ech->ec);
			assign_aeb_to_av(ai, tmp_aeb, av);
		}

		kfree(ech);
	}

	ret = scan_pool(ubi, ai, fmpl1->pebs, pool_size, &max_sqnum,
			&eba_orphans, &free);
	if (ret)
		goto fail;

	ret = scan_pool(ubi, ai, fmpl2->pebs, wl_pool_size, &max_sqnum,
			&eba_orphans, &free);
	if (ret)
		goto fail;

	if (max_sqnum > ai->max_sqnum)
		ai->max_sqnum = max_sqnum;

826 827
	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list)
		list_move_tail(&tmp_aeb->u.list, &ai->free);
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	/*
	 * If fastmap is leaking PEBs (must not happen), raise a
	 * fat warning and fall back to scanning mode.
	 * We do this here because in ubi_wl_init() it's too late
	 * and we cannot fall back to scanning.
	 */
	if (WARN_ON(count_fastmap_pebs(ai) != ubi->peb_count -
		    ai->bad_peb_count - fm->used_blocks))
		goto fail_bad;

	return 0;

fail_bad:
	ret = UBI_BAD_FASTMAP;
fail:
844 845 846 847 848 849 850 851 852 853 854 855 856
	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &used, u.list) {
		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
		list_del(&tmp_aeb->u.list);
	}
	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &eba_orphans, u.list) {
		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
		list_del(&tmp_aeb->u.list);
	}
	list_for_each_entry_safe(tmp_aeb, _tmp_aeb, &free, u.list) {
		kmem_cache_free(ai->aeb_slab_cache, tmp_aeb);
		list_del(&tmp_aeb->u.list);
	}

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	return ret;
}

/**
 * ubi_scan_fastmap - scan the fastmap.
 * @ubi: UBI device object
 * @ai: UBI attach info to be filled
 * @fm_anchor: The fastmap starts at this PEB
 *
 * Returns 0 on success, UBI_NO_FASTMAP if no fastmap was found,
 * UBI_BAD_FASTMAP if one was found but is not usable.
 * < 0 indicates an internal error.
 */
int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
		     int fm_anchor)
{
	struct ubi_fm_sb *fmsb, *fmsb2;
	struct ubi_vid_hdr *vh;
	struct ubi_ec_hdr *ech;
	struct ubi_fastmap_layout *fm;
	int i, used_blocks, pnum, ret = 0;
	size_t fm_size;
	__be32 crc, tmp_crc;
	unsigned long long sqnum = 0;

	mutex_lock(&ubi->fm_mutex);
	memset(ubi->fm_buf, 0, ubi->fm_size);

	fmsb = kmalloc(sizeof(*fmsb), GFP_KERNEL);
	if (!fmsb) {
		ret = -ENOMEM;
		goto out;
	}

	fm = kzalloc(sizeof(*fm), GFP_KERNEL);
	if (!fm) {
		ret = -ENOMEM;
		kfree(fmsb);
		goto out;
	}

	ret = ubi_io_read(ubi, fmsb, fm_anchor, ubi->leb_start, sizeof(*fmsb));
	if (ret && ret != UBI_IO_BITFLIPS)
		goto free_fm_sb;
	else if (ret == UBI_IO_BITFLIPS)
		fm->to_be_tortured[0] = 1;

	if (be32_to_cpu(fmsb->magic) != UBI_FM_SB_MAGIC) {
		ubi_err("bad super block magic: 0x%x, expected: 0x%x",
			be32_to_cpu(fmsb->magic), UBI_FM_SB_MAGIC);
		ret = UBI_BAD_FASTMAP;
		goto free_fm_sb;
	}

	if (fmsb->version != UBI_FM_FMT_VERSION) {
		ubi_err("bad fastmap version: %i, expected: %i",
			fmsb->version, UBI_FM_FMT_VERSION);
		ret = UBI_BAD_FASTMAP;
		goto free_fm_sb;
	}

	used_blocks = be32_to_cpu(fmsb->used_blocks);
	if (used_blocks > UBI_FM_MAX_BLOCKS || used_blocks < 1) {
		ubi_err("number of fastmap blocks is invalid: %i", used_blocks);
		ret = UBI_BAD_FASTMAP;
		goto free_fm_sb;
	}

	fm_size = ubi->leb_size * used_blocks;
	if (fm_size != ubi->fm_size) {
		ubi_err("bad fastmap size: %zi, expected: %zi", fm_size,
			ubi->fm_size);
		ret = UBI_BAD_FASTMAP;
		goto free_fm_sb;
	}

	ech = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
	if (!ech) {
		ret = -ENOMEM;
		goto free_fm_sb;
	}

	vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
	if (!vh) {
		ret = -ENOMEM;
		goto free_hdr;
	}

	for (i = 0; i < used_blocks; i++) {
946 947
		int image_seq;

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Richard Weinberger 已提交
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		pnum = be32_to_cpu(fmsb->block_loc[i]);

		if (ubi_io_is_bad(ubi, pnum)) {
			ret = UBI_BAD_FASTMAP;
			goto free_hdr;
		}

		ret = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
		if (ret && ret != UBI_IO_BITFLIPS) {
			ubi_err("unable to read fastmap block# %i EC (PEB: %i)",
				i, pnum);
			if (ret > 0)
				ret = UBI_BAD_FASTMAP;
			goto free_hdr;
		} else if (ret == UBI_IO_BITFLIPS)
			fm->to_be_tortured[i] = 1;

965
		image_seq = be32_to_cpu(ech->image_seq);
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Richard Weinberger 已提交
966
		if (!ubi->image_seq)
967
			ubi->image_seq = image_seq;
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Richard Weinberger 已提交
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969 970 971 972 973 974 975
		/*
		 * Older UBI implementations have image_seq set to zero, so
		 * we shouldn't fail if image_seq == 0.
		 */
		if (image_seq && (image_seq != ubi->image_seq)) {
			ubi_err("wrong image seq:%d instead of %d",
				be32_to_cpu(ech->image_seq), ubi->image_seq);
R
Richard Weinberger 已提交
976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374
			ret = UBI_BAD_FASTMAP;
			goto free_hdr;
		}

		ret = ubi_io_read_vid_hdr(ubi, pnum, vh, 0);
		if (ret && ret != UBI_IO_BITFLIPS) {
			ubi_err("unable to read fastmap block# %i (PEB: %i)",
				i, pnum);
			goto free_hdr;
		}

		if (i == 0) {
			if (be32_to_cpu(vh->vol_id) != UBI_FM_SB_VOLUME_ID) {
				ubi_err("bad fastmap anchor vol_id: 0x%x," \
					" expected: 0x%x",
					be32_to_cpu(vh->vol_id),
					UBI_FM_SB_VOLUME_ID);
				ret = UBI_BAD_FASTMAP;
				goto free_hdr;
			}
		} else {
			if (be32_to_cpu(vh->vol_id) != UBI_FM_DATA_VOLUME_ID) {
				ubi_err("bad fastmap data vol_id: 0x%x," \
					" expected: 0x%x",
					be32_to_cpu(vh->vol_id),
					UBI_FM_DATA_VOLUME_ID);
				ret = UBI_BAD_FASTMAP;
				goto free_hdr;
			}
		}

		if (sqnum < be64_to_cpu(vh->sqnum))
			sqnum = be64_to_cpu(vh->sqnum);

		ret = ubi_io_read(ubi, ubi->fm_buf + (ubi->leb_size * i), pnum,
				  ubi->leb_start, ubi->leb_size);
		if (ret && ret != UBI_IO_BITFLIPS) {
			ubi_err("unable to read fastmap block# %i (PEB: %i, " \
				"err: %i)", i, pnum, ret);
			goto free_hdr;
		}
	}

	kfree(fmsb);
	fmsb = NULL;

	fmsb2 = (struct ubi_fm_sb *)(ubi->fm_buf);
	tmp_crc = be32_to_cpu(fmsb2->data_crc);
	fmsb2->data_crc = 0;
	crc = crc32(UBI_CRC32_INIT, ubi->fm_buf, fm_size);
	if (crc != tmp_crc) {
		ubi_err("fastmap data CRC is invalid");
		ubi_err("CRC should be: 0x%x, calc: 0x%x", tmp_crc, crc);
		ret = UBI_BAD_FASTMAP;
		goto free_hdr;
	}

	fmsb2->sqnum = sqnum;

	fm->used_blocks = used_blocks;

	ret = ubi_attach_fastmap(ubi, ai, fm);
	if (ret) {
		if (ret > 0)
			ret = UBI_BAD_FASTMAP;
		goto free_hdr;
	}

	for (i = 0; i < used_blocks; i++) {
		struct ubi_wl_entry *e;

		e = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
		if (!e) {
			while (i--)
				kfree(fm->e[i]);

			ret = -ENOMEM;
			goto free_hdr;
		}

		e->pnum = be32_to_cpu(fmsb2->block_loc[i]);
		e->ec = be32_to_cpu(fmsb2->block_ec[i]);
		fm->e[i] = e;
	}

	ubi->fm = fm;
	ubi->fm_pool.max_size = ubi->fm->max_pool_size;
	ubi->fm_wl_pool.max_size = ubi->fm->max_wl_pool_size;
	ubi_msg("attached by fastmap");
	ubi_msg("fastmap pool size: %d", ubi->fm_pool.max_size);
	ubi_msg("fastmap WL pool size: %d", ubi->fm_wl_pool.max_size);
	ubi->fm_disabled = 0;

	ubi_free_vid_hdr(ubi, vh);
	kfree(ech);
out:
	mutex_unlock(&ubi->fm_mutex);
	if (ret == UBI_BAD_FASTMAP)
		ubi_err("Attach by fastmap failed, doing a full scan!");
	return ret;

free_hdr:
	ubi_free_vid_hdr(ubi, vh);
	kfree(ech);
free_fm_sb:
	kfree(fmsb);
	kfree(fm);
	goto out;
}

/**
 * ubi_write_fastmap - writes a fastmap.
 * @ubi: UBI device object
 * @new_fm: the to be written fastmap
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
static int ubi_write_fastmap(struct ubi_device *ubi,
			     struct ubi_fastmap_layout *new_fm)
{
	size_t fm_pos = 0;
	void *fm_raw;
	struct ubi_fm_sb *fmsb;
	struct ubi_fm_hdr *fmh;
	struct ubi_fm_scan_pool *fmpl1, *fmpl2;
	struct ubi_fm_ec *fec;
	struct ubi_fm_volhdr *fvh;
	struct ubi_fm_eba *feba;
	struct rb_node *node;
	struct ubi_wl_entry *wl_e;
	struct ubi_volume *vol;
	struct ubi_vid_hdr *avhdr, *dvhdr;
	struct ubi_work *ubi_wrk;
	int ret, i, j, free_peb_count, used_peb_count, vol_count;
	int scrub_peb_count, erase_peb_count;

	fm_raw = ubi->fm_buf;
	memset(ubi->fm_buf, 0, ubi->fm_size);

	avhdr = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
	if (!avhdr) {
		ret = -ENOMEM;
		goto out;
	}

	dvhdr = new_fm_vhdr(ubi, UBI_FM_DATA_VOLUME_ID);
	if (!dvhdr) {
		ret = -ENOMEM;
		goto out_kfree;
	}

	spin_lock(&ubi->volumes_lock);
	spin_lock(&ubi->wl_lock);

	fmsb = (struct ubi_fm_sb *)fm_raw;
	fm_pos += sizeof(*fmsb);
	ubi_assert(fm_pos <= ubi->fm_size);

	fmh = (struct ubi_fm_hdr *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmh);
	ubi_assert(fm_pos <= ubi->fm_size);

	fmsb->magic = cpu_to_be32(UBI_FM_SB_MAGIC);
	fmsb->version = UBI_FM_FMT_VERSION;
	fmsb->used_blocks = cpu_to_be32(new_fm->used_blocks);
	/* the max sqnum will be filled in while *reading* the fastmap */
	fmsb->sqnum = 0;

	fmh->magic = cpu_to_be32(UBI_FM_HDR_MAGIC);
	free_peb_count = 0;
	used_peb_count = 0;
	scrub_peb_count = 0;
	erase_peb_count = 0;
	vol_count = 0;

	fmpl1 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmpl1);
	fmpl1->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
	fmpl1->size = cpu_to_be16(ubi->fm_pool.size);
	fmpl1->max_size = cpu_to_be16(ubi->fm_pool.max_size);

	for (i = 0; i < ubi->fm_pool.size; i++)
		fmpl1->pebs[i] = cpu_to_be32(ubi->fm_pool.pebs[i]);

	fmpl2 = (struct ubi_fm_scan_pool *)(fm_raw + fm_pos);
	fm_pos += sizeof(*fmpl2);
	fmpl2->magic = cpu_to_be32(UBI_FM_POOL_MAGIC);
	fmpl2->size = cpu_to_be16(ubi->fm_wl_pool.size);
	fmpl2->max_size = cpu_to_be16(ubi->fm_wl_pool.max_size);

	for (i = 0; i < ubi->fm_wl_pool.size; i++)
		fmpl2->pebs[i] = cpu_to_be32(ubi->fm_wl_pool.pebs[i]);

	for (node = rb_first(&ubi->free); node; node = rb_next(node)) {
		wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);

		fec->pnum = cpu_to_be32(wl_e->pnum);
		fec->ec = cpu_to_be32(wl_e->ec);

		free_peb_count++;
		fm_pos += sizeof(*fec);
		ubi_assert(fm_pos <= ubi->fm_size);
	}
	fmh->free_peb_count = cpu_to_be32(free_peb_count);

	for (node = rb_first(&ubi->used); node; node = rb_next(node)) {
		wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);

		fec->pnum = cpu_to_be32(wl_e->pnum);
		fec->ec = cpu_to_be32(wl_e->ec);

		used_peb_count++;
		fm_pos += sizeof(*fec);
		ubi_assert(fm_pos <= ubi->fm_size);
	}
	fmh->used_peb_count = cpu_to_be32(used_peb_count);

	for (node = rb_first(&ubi->scrub); node; node = rb_next(node)) {
		wl_e = rb_entry(node, struct ubi_wl_entry, u.rb);
		fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);

		fec->pnum = cpu_to_be32(wl_e->pnum);
		fec->ec = cpu_to_be32(wl_e->ec);

		scrub_peb_count++;
		fm_pos += sizeof(*fec);
		ubi_assert(fm_pos <= ubi->fm_size);
	}
	fmh->scrub_peb_count = cpu_to_be32(scrub_peb_count);


	list_for_each_entry(ubi_wrk, &ubi->works, list) {
		if (ubi_is_erase_work(ubi_wrk)) {
			wl_e = ubi_wrk->e;
			ubi_assert(wl_e);

			fec = (struct ubi_fm_ec *)(fm_raw + fm_pos);

			fec->pnum = cpu_to_be32(wl_e->pnum);
			fec->ec = cpu_to_be32(wl_e->ec);

			erase_peb_count++;
			fm_pos += sizeof(*fec);
			ubi_assert(fm_pos <= ubi->fm_size);
		}
	}
	fmh->erase_peb_count = cpu_to_be32(erase_peb_count);

	for (i = 0; i < UBI_MAX_VOLUMES + UBI_INT_VOL_COUNT; i++) {
		vol = ubi->volumes[i];

		if (!vol)
			continue;

		vol_count++;

		fvh = (struct ubi_fm_volhdr *)(fm_raw + fm_pos);
		fm_pos += sizeof(*fvh);
		ubi_assert(fm_pos <= ubi->fm_size);

		fvh->magic = cpu_to_be32(UBI_FM_VHDR_MAGIC);
		fvh->vol_id = cpu_to_be32(vol->vol_id);
		fvh->vol_type = vol->vol_type;
		fvh->used_ebs = cpu_to_be32(vol->used_ebs);
		fvh->data_pad = cpu_to_be32(vol->data_pad);
		fvh->last_eb_bytes = cpu_to_be32(vol->last_eb_bytes);

		ubi_assert(vol->vol_type == UBI_DYNAMIC_VOLUME ||
			vol->vol_type == UBI_STATIC_VOLUME);

		feba = (struct ubi_fm_eba *)(fm_raw + fm_pos);
		fm_pos += sizeof(*feba) + (sizeof(__be32) * vol->reserved_pebs);
		ubi_assert(fm_pos <= ubi->fm_size);

		for (j = 0; j < vol->reserved_pebs; j++)
			feba->pnum[j] = cpu_to_be32(vol->eba_tbl[j]);

		feba->reserved_pebs = cpu_to_be32(j);
		feba->magic = cpu_to_be32(UBI_FM_EBA_MAGIC);
	}
	fmh->vol_count = cpu_to_be32(vol_count);
	fmh->bad_peb_count = cpu_to_be32(ubi->bad_peb_count);

	avhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
	avhdr->lnum = 0;

	spin_unlock(&ubi->wl_lock);
	spin_unlock(&ubi->volumes_lock);

	dbg_bld("writing fastmap SB to PEB %i", new_fm->e[0]->pnum);
	ret = ubi_io_write_vid_hdr(ubi, new_fm->e[0]->pnum, avhdr);
	if (ret) {
		ubi_err("unable to write vid_hdr to fastmap SB!");
		goto out_kfree;
	}

	for (i = 0; i < new_fm->used_blocks; i++) {
		fmsb->block_loc[i] = cpu_to_be32(new_fm->e[i]->pnum);
		fmsb->block_ec[i] = cpu_to_be32(new_fm->e[i]->ec);
	}

	fmsb->data_crc = 0;
	fmsb->data_crc = cpu_to_be32(crc32(UBI_CRC32_INIT, fm_raw,
					   ubi->fm_size));

	for (i = 1; i < new_fm->used_blocks; i++) {
		dvhdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
		dvhdr->lnum = cpu_to_be32(i);
		dbg_bld("writing fastmap data to PEB %i sqnum %llu",
			new_fm->e[i]->pnum, be64_to_cpu(dvhdr->sqnum));
		ret = ubi_io_write_vid_hdr(ubi, new_fm->e[i]->pnum, dvhdr);
		if (ret) {
			ubi_err("unable to write vid_hdr to PEB %i!",
				new_fm->e[i]->pnum);
			goto out_kfree;
		}
	}

	for (i = 0; i < new_fm->used_blocks; i++) {
		ret = ubi_io_write(ubi, fm_raw + (i * ubi->leb_size),
			new_fm->e[i]->pnum, ubi->leb_start, ubi->leb_size);
		if (ret) {
			ubi_err("unable to write fastmap to PEB %i!",
				new_fm->e[i]->pnum);
			goto out_kfree;
		}
	}

	ubi_assert(new_fm);
	ubi->fm = new_fm;

	dbg_bld("fastmap written!");

out_kfree:
	ubi_free_vid_hdr(ubi, avhdr);
	ubi_free_vid_hdr(ubi, dvhdr);
out:
	return ret;
}

/**
 * erase_block - Manually erase a PEB.
 * @ubi: UBI device object
 * @pnum: PEB to be erased
 *
 * Returns the new EC value on success, < 0 indicates an internal error.
 */
static int erase_block(struct ubi_device *ubi, int pnum)
{
	int ret;
	struct ubi_ec_hdr *ec_hdr;
	long long ec;

	ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
	if (!ec_hdr)
		return -ENOMEM;

	ret = ubi_io_read_ec_hdr(ubi, pnum, ec_hdr, 0);
	if (ret < 0)
		goto out;
	else if (ret && ret != UBI_IO_BITFLIPS) {
		ret = -EINVAL;
		goto out;
	}

	ret = ubi_io_sync_erase(ubi, pnum, 0);
	if (ret < 0)
		goto out;

	ec = be64_to_cpu(ec_hdr->ec);
	ec += ret;
	if (ec > UBI_MAX_ERASECOUNTER) {
		ret = -EINVAL;
		goto out;
	}

	ec_hdr->ec = cpu_to_be64(ec);
	ret = ubi_io_write_ec_hdr(ubi, pnum, ec_hdr);
	if (ret < 0)
		goto out;

	ret = ec;
out:
	kfree(ec_hdr);
	return ret;
}

/**
 * invalidate_fastmap - destroys a fastmap.
 * @ubi: UBI device object
 * @fm: the fastmap to be destroyed
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
static int invalidate_fastmap(struct ubi_device *ubi,
			      struct ubi_fastmap_layout *fm)
{
1375
	int ret;
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	struct ubi_vid_hdr *vh;

	ret = erase_block(ubi, fm->e[0]->pnum);
	if (ret < 0)
		return ret;

	vh = new_fm_vhdr(ubi, UBI_FM_SB_VOLUME_ID);
	if (!vh)
		return -ENOMEM;

	/* deleting the current fastmap SB is not enough, an old SB may exist,
	 * so create a (corrupted) SB such that fastmap will find it and fall
	 * back to scanning mode in any case */
	vh->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
	ret = ubi_io_write_vid_hdr(ubi, fm->e[0]->pnum, vh);

	return ret;
}

/**
 * ubi_update_fastmap - will be called by UBI if a volume changes or
 * a fastmap pool becomes full.
 * @ubi: UBI device object
 *
 * Returns 0 on success, < 0 indicates an internal error.
 */
int ubi_update_fastmap(struct ubi_device *ubi)
{
	int ret, i;
	struct ubi_fastmap_layout *new_fm, *old_fm;
	struct ubi_wl_entry *tmp_e;

	mutex_lock(&ubi->fm_mutex);

	ubi_refill_pools(ubi);

	if (ubi->ro_mode || ubi->fm_disabled) {
		mutex_unlock(&ubi->fm_mutex);
		return 0;
	}

	ret = ubi_ensure_anchor_pebs(ubi);
	if (ret) {
		mutex_unlock(&ubi->fm_mutex);
		return ret;
	}

	new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
	if (!new_fm) {
		mutex_unlock(&ubi->fm_mutex);
		return -ENOMEM;
	}

	new_fm->used_blocks = ubi->fm_size / ubi->leb_size;

	for (i = 0; i < new_fm->used_blocks; i++) {
		new_fm->e[i] = kmem_cache_alloc(ubi_wl_entry_slab, GFP_KERNEL);
		if (!new_fm->e[i]) {
			while (i--)
				kfree(new_fm->e[i]);

			kfree(new_fm);
			mutex_unlock(&ubi->fm_mutex);
			return -ENOMEM;
		}
	}

	old_fm = ubi->fm;
	ubi->fm = NULL;

	if (new_fm->used_blocks > UBI_FM_MAX_BLOCKS) {
		ubi_err("fastmap too large");
		ret = -ENOSPC;
		goto err;
	}

	for (i = 1; i < new_fm->used_blocks; i++) {
		spin_lock(&ubi->wl_lock);
		tmp_e = ubi_wl_get_fm_peb(ubi, 0);
		spin_unlock(&ubi->wl_lock);

		if (!tmp_e && !old_fm) {
			int j;
			ubi_err("could not get any free erase block");

			for (j = 1; j < i; j++)
				ubi_wl_put_fm_peb(ubi, new_fm->e[j], j, 0);

			ret = -ENOSPC;
			goto err;
		} else if (!tmp_e && old_fm) {
			ret = erase_block(ubi, old_fm->e[i]->pnum);
			if (ret < 0) {
				int j;

				for (j = 1; j < i; j++)
					ubi_wl_put_fm_peb(ubi, new_fm->e[j],
							  j, 0);

				ubi_err("could not erase old fastmap PEB");
				goto err;
			}

			new_fm->e[i]->pnum = old_fm->e[i]->pnum;
			new_fm->e[i]->ec = old_fm->e[i]->ec;
		} else {
			new_fm->e[i]->pnum = tmp_e->pnum;
			new_fm->e[i]->ec = tmp_e->ec;

			if (old_fm)
				ubi_wl_put_fm_peb(ubi, old_fm->e[i], i,
						  old_fm->to_be_tortured[i]);
		}
	}

	spin_lock(&ubi->wl_lock);
	tmp_e = ubi_wl_get_fm_peb(ubi, 1);
	spin_unlock(&ubi->wl_lock);

	if (old_fm) {
		/* no fresh anchor PEB was found, reuse the old one */
		if (!tmp_e) {
			ret = erase_block(ubi, old_fm->e[0]->pnum);
			if (ret < 0) {
				int i;
				ubi_err("could not erase old anchor PEB");

				for (i = 1; i < new_fm->used_blocks; i++)
					ubi_wl_put_fm_peb(ubi, new_fm->e[i],
							  i, 0);
				goto err;
			}

			new_fm->e[0]->pnum = old_fm->e[0]->pnum;
			new_fm->e[0]->ec = ret;
		} else {
			/* we've got a new anchor PEB, return the old one */
			ubi_wl_put_fm_peb(ubi, old_fm->e[0], 0,
					  old_fm->to_be_tortured[0]);

			new_fm->e[0]->pnum = tmp_e->pnum;
			new_fm->e[0]->ec = tmp_e->ec;
		}
	} else {
		if (!tmp_e) {
			int i;
			ubi_err("could not find any anchor PEB");

			for (i = 1; i < new_fm->used_blocks; i++)
				ubi_wl_put_fm_peb(ubi, new_fm->e[i], i, 0);

			ret = -ENOSPC;
			goto err;
		}

		new_fm->e[0]->pnum = tmp_e->pnum;
		new_fm->e[0]->ec = tmp_e->ec;
	}

	down_write(&ubi->work_sem);
	down_write(&ubi->fm_sem);
	ret = ubi_write_fastmap(ubi, new_fm);
	up_write(&ubi->fm_sem);
	up_write(&ubi->work_sem);

	if (ret)
		goto err;

out_unlock:
	mutex_unlock(&ubi->fm_mutex);
	kfree(old_fm);
	return ret;

err:
	kfree(new_fm);

	ubi_warn("Unable to write new fastmap, err=%i", ret);

	ret = 0;
	if (old_fm) {
		ret = invalidate_fastmap(ubi, old_fm);
		if (ret < 0)
			ubi_err("Unable to invalidiate current fastmap!");
		else if (ret)
			ret = 0;
	}
	goto out_unlock;
}