eba.c

基于linux-2.6.28的mtd驱动

		}

		err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
		if (err && err != UBI_IO_BITFLIPS) {
			if (err > 0) {
				/*
				 * The header is either absent or corrupted.
				 * The former case means there is a bug -
				 * switch to read-only mode just in case.
				 * The latter case means a real corruption - we
				 * may try to recover data. FIXME: but this is
				 * not implemented.
				 */
				if (err == UBI_IO_BAD_VID_HDR) {
					ubi_warn("bad VID header at PEB %d, LEB"
						 "%d:%d", pnum, vol_id, lnum);
					err = -EBADMSG;
				} else
					ubi_ro_mode(ubi);
			}
			goto out_free;
		} else if (err == UBI_IO_BITFLIPS)
			scrub = 1;

		ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs));
		ubi_assert(len == be32_to_cpu(vid_hdr->data_size));

		crc = be32_to_cpu(vid_hdr->data_crc);
		ubi_free_vid_hdr(ubi, vid_hdr);
	}

	err = ubi_io_read_data(ubi, buf, pnum, offset, len);
	if (err) {
		if (err == UBI_IO_BITFLIPS) {
			scrub = 1;
			err = 0;
		} else if (err == -EBADMSG) {
			if (vol->vol_type == UBI_DYNAMIC_VOLUME)
				goto out_unlock;
			scrub = 1;
			if (!check) {
				ubi_msg("force data checking");
				check = 1;
				goto retry;
			}
		} else
			goto out_unlock;
	}

	if (check) {
		uint32_t crc1 = crc32(UBI_CRC32_INIT, buf, len);
		if (crc1 != crc) {
			ubi_warn("CRC error: calculated %#08x, must be %#08x",
				 crc1, crc);
			err = -EBADMSG;
			goto out_unlock;
		}
	}

	if (scrub)
		err = ubi_wl_scrub_peb(ubi, pnum);

	leb_read_unlock(ubi, vol_id, lnum);
	return err;

out_free:
	ubi_free_vid_hdr(ubi, vid_hdr);
out_unlock:
	leb_read_unlock(ubi, vol_id, lnum);
	return err;
}

/**
 * recover_peb - recover from write failure.
 * @ubi: UBI device description object
 * @pnum: the physical eraseblock to recover
 * @vol_id: volume ID
 * @lnum: logical eraseblock number
 * @buf: data which was not written because of the write failure
 * @offset: offset of the failed write
 * @len: how many bytes should have been written
 *
 * This function is called in case of a write failure and moves all good data
 * from the potentially bad physical eraseblock to a good physical eraseblock.
 * This function also writes the data which was not written due to the failure.
 * Returns new physical eraseblock number in case of success, and a negative
 * error code in case of failure.
 */
static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
		       const void *buf, int offset, int len)
{
	int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
	struct ubi_volume *vol = ubi->volumes[idx];
	struct ubi_vid_hdr *vid_hdr;

	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
	if (!vid_hdr)
		return -ENOMEM;

	mutex_lock(&ubi->buf_mutex);

retry:
	new_pnum = ubi_wl_get_peb(ubi, UBI_UNKNOWN);
	if (new_pnum < 0) {
		mutex_unlock(&ubi->buf_mutex);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return new_pnum;
	}

	ubi_msg("recover PEB %d, move data to PEB %d", pnum, new_pnum);

	err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
	if (err && err != UBI_IO_BITFLIPS) {
		if (err > 0)
			err = -EIO;
		goto out_put;
	}

	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
	err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
	if (err)
		goto write_error;

	data_size = offset + len;
	memset(ubi->peb_buf1 + offset, 0xFF, len);

	/* Read everything before the area where the write failure happened */
	if (offset > 0) {
		err = ubi_io_read_data(ubi, ubi->peb_buf1, pnum, 0, offset);
		if (err && err != UBI_IO_BITFLIPS)
			goto out_put;
	}

	memcpy(ubi->peb_buf1 + offset, buf, len);

	err = ubi_io_write_data(ubi, ubi->peb_buf1, new_pnum, 0, data_size);
	if (err)
		goto write_error;

	mutex_unlock(&ubi->buf_mutex);
	ubi_free_vid_hdr(ubi, vid_hdr);

	vol->eba_tbl[lnum] = new_pnum;
	ubi_wl_put_peb(ubi, pnum, 1);

	ubi_msg("data was successfully recovered");
	return 0;

out_put:
	mutex_unlock(&ubi->buf_mutex);
	ubi_wl_put_peb(ubi, new_pnum, 1);
	ubi_free_vid_hdr(ubi, vid_hdr);
	return err;

write_error:
	/*
	 * Bad luck? This physical eraseblock is bad too? Crud. Let's try to
	 * get another one.
	 */
	ubi_warn("failed to write to PEB %d", new_pnum);
	ubi_wl_put_peb(ubi, new_pnum, 1);
	if (++tries > UBI_IO_RETRIES) {
		mutex_unlock(&ubi->buf_mutex);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}
	ubi_msg("try again");
	goto retry;
}

/**
 * ubi_eba_write_leb - write data to dynamic volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @lnum: logical eraseblock number
 * @buf: the data to write
 * @offset: offset within the logical eraseblock where to write
 * @len: how many bytes to write
 * @dtype: data type
 *
 * This function writes data to logical eraseblock @lnum of a dynamic volume
 * @vol. Returns zero in case of success and a negative error code in case
 * of failure. In case of error, it is possible that something was still
 * written to the flash media, but may be some garbage.
 */
int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
		      const void *buf, int offset, int len, int dtype)
{
	int err, pnum, tries = 0, vol_id = vol->vol_id;
	struct ubi_vid_hdr *vid_hdr;

	if (ubi->ro_mode)
		return -EROFS;

	err = leb_write_lock(ubi, vol_id, lnum);
	if (err)
		return err;

	pnum = vol->eba_tbl[lnum];
	if (pnum >= 0) {
		dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
			len, offset, vol_id, lnum, pnum);

		err = ubi_io_write_data(ubi, buf, pnum, offset, len);
		if (err) {
			ubi_warn("failed to write data to PEB %d", pnum);
			if (err == -EIO && ubi->bad_allowed)
				err = recover_peb(ubi, pnum, vol_id, lnum, buf,
						  offset, len);
			if (err)
				ubi_ro_mode(ubi);
		}
		leb_write_unlock(ubi, vol_id, lnum);
		return err;
	}

	/*
	 * The logical eraseblock is not mapped. We have to get a free physical
	 * eraseblock and write the volume identifier header there first.
	 */
	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
	if (!vid_hdr) {
		leb_write_unlock(ubi, vol_id, lnum);
		return -ENOMEM;
	}

	vid_hdr->vol_type = UBI_VID_DYNAMIC;
	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
	vid_hdr->vol_id = cpu_to_be32(vol_id);
	vid_hdr->lnum = cpu_to_be32(lnum);
	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);

retry:
	pnum = ubi_wl_get_peb(ubi, dtype);
	if (pnum < 0) {
		ubi_free_vid_hdr(ubi, vid_hdr);
		leb_write_unlock(ubi, vol_id, lnum);
		return pnum;
	}

	dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
		len, offset, vol_id, lnum, pnum);

	err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
	if (err) {
		ubi_warn("failed to write VID header to LEB %d:%d, PEB %d",
			 vol_id, lnum, pnum);
		goto write_error;
	}

	if (len) {
		err = ubi_io_write_data(ubi, buf, pnum, offset, len);
		if (err) {
			ubi_warn("failed to write %d bytes at offset %d of "
				 "LEB %d:%d, PEB %d", len, offset, vol_id,
				 lnum, pnum);
			goto write_error;
		}
	}

	vol->eba_tbl[lnum] = pnum;

	leb_write_unlock(ubi, vol_id, lnum);
	ubi_free_vid_hdr(ubi, vid_hdr);
	return 0;

write_error:
	if (err != -EIO || !ubi->bad_allowed) {
		ubi_ro_mode(ubi);
		leb_write_unlock(ubi, vol_id, lnum);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}

	/*
	 * Fortunately, this is the first write operation to this physical
	 * eraseblock, so just put it and request a new one. We assume that if
	 * this physical eraseblock went bad, the erase code will handle that.
	 */
	err = ubi_wl_put_peb(ubi, pnum, 1);
	if (err || ++tries > UBI_IO_RETRIES) {
		ubi_ro_mode(ubi);
		leb_write_unlock(ubi, vol_id, lnum);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}

	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
	ubi_msg("try another PEB");
	goto retry;
}

/**
 * ubi_eba_write_leb_st - write data to static volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 * @lnum: logical eraseblock number
 * @buf: data to write
 * @len: how many bytes to write
 * @dtype: data type
 * @used_ebs: how many logical eraseblocks will this volume contain
 *
 * This function writes data to logical eraseblock @lnum of static volume
 * @vol. The @used_ebs argument should contain total number of logical
 * eraseblock in this static volume.
 *
 * When writing to the last logical eraseblock, the @len argument doesn't have
 * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
 * to the real data size, although the @buf buffer has to contain the
 * alignment. In all other cases, @len has to be aligned.
 *
 * It is prohibited to write more then once to logical eraseblocks of static
 * volumes. This function returns zero in case of success and a negative error
 * code in case of failure.
 */
int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
			 int lnum, const void *buf, int len, int dtype,
			 int used_ebs)
{
	int err, pnum, tries = 0, data_size = len, vol_id = vol->vol_id;
	struct ubi_vid_hdr *vid_hdr;
	uint32_t crc;

	if (ubi->ro_mode)
		return -EROFS;

	if (lnum == used_ebs - 1)
		/* If this is the last LEB @len may be unaligned */
		len = ALIGN(data_size, ubi->min_io_size);
	else
		ubi_assert(!(len & (ubi->min_io_size - 1)));

	vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
	if (!vid_hdr)
		return -ENOMEM;

	err = leb_write_lock(ubi, vol_id, lnum);
	if (err) {
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}

	vid_hdr->sqnum = cpu_to_be64(next_sqnum(ubi));
	vid_hdr->vol_id = cpu_to_be32(vol_id);
	vid_hdr->lnum = cpu_to_be32(lnum);
	vid_hdr->compat = ubi_get_compat(ubi, vol_id);
	vid_hdr->data_pad = cpu_to_be32(vol->data_pad);

	crc = crc32(UBI_CRC32_INIT, buf, data_size);
	vid_hdr->vol_type = UBI_VID_STATIC;
	vid_hdr->data_size = cpu_to_be32(data_size);
	vid_hdr->used_ebs = cpu_to_be32(used_ebs);
	vid_hdr->data_crc = cpu_to_be32(crc);

retry:
	pnum = ubi_wl_get_peb(ubi, dtype);
	if (pnum < 0) {
		ubi_free_vid_hdr(ubi, vid_hdr);
		leb_write_unlock(ubi, vol_id, lnum);
		return pnum;
	}

	dbg_eba("write VID hdr and %d bytes at LEB %d:%d, PEB %d, used_ebs %d",
		len, vol_id, lnum, pnum, used_ebs);

	err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
	if (err) {
		ubi_warn("failed to write VID header to LEB %d:%d, PEB %d",
			 vol_id, lnum, pnum);
		goto write_error;
	}

	err = ubi_io_write_data(ubi, buf, pnum, 0, len);
	if (err) {
		ubi_warn("failed to write %d bytes of data to PEB %d",
			 len, pnum);
		goto write_error;
	}

	ubi_assert(vol->eba_tbl[lnum] < 0);
	vol->eba_tbl[lnum] = pnum;

	leb_write_unlock(ubi, vol_id, lnum);
	ubi_free_vid_hdr(ubi, vid_hdr);
	return 0;

write_error:
	if (err != -EIO || !ubi->bad_allowed) {
		/*
		 * This flash device does not admit of bad eraseblocks or
		 * something nasty and unexpected happened. Switch to read-only
		 * mode just in case.
		 */
		ubi_ro_mode(ubi);
		leb_write_unlock(ubi, vol_id, lnum);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}

	err = ubi_wl_put_peb(ubi, pnum, 1);
	if (err || ++tries > UBI_IO_RETRIES) {
		ubi_ro_mode(ubi);
		leb_write_unlock(ubi, vol_id, lnum);
		ubi_free_vid_hdr(ubi, vid_hdr);
		return err;
	}