Exemple #1
0
/**
 * ubifs_write_node - write node to the media.
 * @c: UBIFS file-system description object
 * @buf: the node to write
 * @len: node length
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 * @dtype: node life-time hint (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
 *
 * This function automatically fills node magic number, assigns sequence
 * number, and calculates node CRC checksum. The length of the @buf buffer has
 * to be aligned to the minimal I/O unit size. This function automatically
 * appends padding node and padding bytes if needed. Returns zero in case of
 * success and a negative error code in case of failure.
 */
int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
		     int offs, int dtype)
{
	int err, buf_len = ALIGN(len, c->min_io_size);

	dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
	       lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
	       buf_len);
	ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(offs % c->min_io_size == 0 && offs < c->leb_size);
	ubifs_assert(!c->ro_media && !c->ro_mount);
	ubifs_assert(!c->space_fixup);

	if (c->ro_error)
		return -EROFS;

	ubifs_prepare_node(c, buf, len, 1);
	err = ubi_leb_write(c->ubi, lnum, buf, offs, buf_len, dtype);
	if (err) {
		ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
			  buf_len, lnum, offs, err);
		dbg_dump_node(c, buf);
		dbg_dump_stack();
	}

	return err;
}
/**
 * ubifs_scan_a_node - scan for a node or padding.
 * @c: UBIFS file-system description object
 * @buf: buffer to scan
 * @len: length of buffer
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 * @quiet: print no messages
 *
 * This function returns a scanning code to indicate what was scanned.
 */
int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
		      int offs, int quiet)
{
	struct ubifs_ch *ch = buf;
	uint32_t magic;

	magic = le32_to_cpu(ch->magic);

	if (magic == 0xFFFFFFFF) {
		dbg_scan("hit empty space at LEB %d:%d", lnum, offs);
		return SCANNED_EMPTY_SPACE;
	}

	if (magic != UBIFS_NODE_MAGIC)
		return scan_padding_bytes(buf, len);

	if (len < UBIFS_CH_SZ)
		return SCANNED_GARBAGE;

	dbg_scan("scanning %s at LEB %d:%d",
		 dbg_ntype(ch->node_type), lnum, offs);

	if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
		return SCANNED_A_CORRUPT_NODE;

	if (ch->node_type == UBIFS_PAD_NODE) {
		struct ubifs_pad_node *pad = buf;
		int pad_len = le32_to_cpu(pad->pad_len);
		int node_len = le32_to_cpu(ch->len);

		/* Validate the padding node */
		if (pad_len < 0 ||
		    offs + node_len + pad_len > c->leb_size) {
			if (!quiet) {
				ubifs_err("bad pad node at LEB %d:%d",
						c->vi.ubi_num, lnum, offs);
				ubifs_dump_node(c, pad);
			}
			return SCANNED_A_BAD_PAD_NODE;
		}

		/* Make the node pads to 8-byte boundary */
		if ((node_len + pad_len) & 7) {
			if (!quiet)
				ubifs_err("bad padding length %d - %d",
						c->vi.ubi_num, offs,
						offs + node_len + pad_len);
			return SCANNED_A_BAD_PAD_NODE;
		}

		dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,
			 lnum, offs, ALIGN(offs + node_len + pad_len, 8));

		return node_len + pad_len;
	}

	return SCANNED_A_NODE;
}
Exemple #3
0
/**
 * ubifs_read_node - read node.
 * @c: UBIFS file-system description object
 * @buf: buffer to read to
 * @type: node type
 * @len: node length (not aligned)
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 *
 * This function reads a node of known type and and length, checks it and
 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
 * and a negative error code in case of failure.
 */
int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
		    int lnum, int offs)
{
	int err, l;
	struct ubifs_ch *ch = buf;
       int try_count = 0;

	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
	ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
	ubifs_assert(!(offs & 7) && offs < c->leb_size);
	ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);

try_read:
	err = ubi_read(c->ubi, lnum, buf, offs, len);
	if (err && err != -EBADMSG) {
		ubifs_err("cannot read node %d from LEB %d:%d, error %d",
			  type, lnum, offs, err);
		return err;
	}

	if (type != ch->node_type) {
		ubifs_err("bad node type (%d but expected %d)",
			  ch->node_type, type);
		goto out;
	}

	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
	if (err) {
		ubifs_err("expected node type %d", type);
              if(try_count < 3){
                  try_count++;
                  udelay(100);
                  goto try_read;
              }
              else{
		   return err;
              }
	}

	l = le32_to_cpu(ch->len);
	if (l != len) {
		ubifs_err("bad node length %d, expected %d", l, len);
		goto out;
	}

	return 0;

out:
	ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs,
		  ubi_is_mapped(c->ubi, lnum));
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	return -EINVAL;
}
/**
 * ubifs_read_node - read node.
 * @c: UBIFS file-system description object
 * @buf: buffer to read to
 * @type: node type
 * @len: node length (not aligned)
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 *
 * This function reads a node of known type and and length, checks it and
 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
 * and a negative error code in case of failure.
 */
int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
		    int lnum, int offs)
{
	int err, l;
	struct ubifs_ch *ch = buf;
#if defined(FEATURE_UBIFS_PERF_INDEX)
	unsigned long long time1 = sched_clock();
#endif

	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
	ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
	ubifs_assert(!(offs & 7) && offs < c->leb_size);
	ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);

	err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
	if (err && err != -EBADMSG)
		return err;

	if (type != ch->node_type) {
		ubifs_err("bad node type (%d but expected %d)",
			  ch->node_type, type);
		goto out;
	}

	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
	if (err) {
		ubifs_err("expected node type %d", type);
		return err;
	}

	l = le32_to_cpu(ch->len);
	if (l != len) {
		ubifs_err("bad node length %d, expected %d", l, len);
		goto out;
	}

#if defined(FEATURE_UBIFS_PERF_INDEX)
	if(type == UBIFS_DATA_NODE) {
		ubifs_perf_lrcount(sched_clock() - time1, len);
	}
#endif
	return 0;

out:
	ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs,
		  ubi_is_mapped(c->ubi, lnum));
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	return -EINVAL;
}
Exemple #5
0
/**
 * ubifs_read_node - read node.
 * @c: UBIFS file-system description object
 * @buf: buffer to read to
 * @type: node type
 * @len: node length (not aligned)
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 *
 * This function reads a node of known type and and length, checks it and
 * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
 * and a negative error code in case of failure.
 */
int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
		    int lnum, int offs)
{
	int err, l;
	struct ubifs_ch *ch = buf;

	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
	ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);

	err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
	if (err && err != -EBADMSG)
		return err;

	if (type != ch->node_type) {
		ubifs_errc(c, "bad node type (%d but expected %d)",
			   ch->node_type, type);
		goto out;
	}

	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
	if (err) {
		ubifs_errc(c, "expected node type %d", type);
		return err;
	}

	l = le32_to_cpu(ch->len);
	if (l != len) {
		ubifs_errc(c, "bad node length %d, expected %d", l, len);
		goto out;
	}

	return 0;

out:
	ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
		   offs, ubi_is_mapped(c->ubi, lnum));
	if (!c->probing) {
		ubifs_dump_node(c, buf);
		dump_stack();
	}
	return -EINVAL;
}
/**
 * ubifs_read_node_wbuf - read node from the media or write-buffer.
 * @wbuf: wbuf to check for un-written data
 * @buf: buffer to read to
 * @type: node type
 * @len: node length
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 *
 * This function reads a node of known type and length, checks it and stores
 * in @buf. If the node partially or fully sits in the write-buffer, this
 * function takes data from the buffer, otherwise it reads the flash media.
 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
 * error code in case of failure.
 */
int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
			 int lnum, int offs)
{
	const struct ubifs_info *c = wbuf->c;
	int err, rlen, overlap;
	struct ubifs_ch *ch = buf;
#if defined(FEATURE_UBIFS_PERF_INDEX)
	unsigned long long time1 = sched_clock();
	int log_len = 0;
#endif

	dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
	       dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
	ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(!(offs & 7) && offs < c->leb_size);
	ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);

	spin_lock(&wbuf->lock);
	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
	if (!overlap) {
		/* We may safely unlock the write-buffer and read the data */
		spin_unlock(&wbuf->lock);
		return ubifs_read_node(c, buf, type, len, lnum, offs);
	}

	/* Don't read under wbuf */
	rlen = wbuf->offs - offs;
	if (rlen < 0)
		rlen = 0;

	/* Copy the rest from the write-buffer */
	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
	spin_unlock(&wbuf->lock);

	if (rlen > 0) {
		/* Read everything that goes before write-buffer */
		err = ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
		if (err && err != -EBADMSG)
			return err;
	}

	if (type != ch->node_type) {
		ubifs_err("bad node type (%d but expected %d)",
			  ch->node_type, type);
		goto out;
	}

	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
	if (err) {
		ubifs_err("expected node type %d", type);
		return err;
	}

	rlen = le32_to_cpu(ch->len);
	if (rlen != len) {
		ubifs_err("bad node length %d, expected %d", rlen, len);
		goto out;
	}

#if defined(FEATURE_UBIFS_PERF_INDEX)
	if(log_len > 0) {
		ubifs_perf_lrcount(sched_clock() - time1, log_len);
	}
#endif
	return 0;

out:
	ubifs_err("bad node at LEB %d:%d", lnum, offs);
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	return -EINVAL;
}
/**
 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
 * @wbuf: write-buffer
 * @buf: node to write
 * @len: node length
 *
 * This function writes data to flash via write-buffer @wbuf. This means that
 * the last piece of the node won't reach the flash media immediately if it
 * does not take whole max. write unit (@c->max_write_size). Instead, the node
 * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or
 * because more data are appended to the write-buffer).
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure. If the node cannot be written because there is no more
 * space in this logical eraseblock, %-ENOSPC is returned.
 */
int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
{
	struct ubifs_info *c = wbuf->c;
	int err, written, n, aligned_len = ALIGN(len, 8);

	dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,
	       dbg_ntype(((struct ubifs_ch *)buf)->node_type),
	       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);
	ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
	ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
	ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
	ubifs_assert(wbuf->avail > 0 && wbuf->avail <= wbuf->size);
	ubifs_assert(wbuf->size >= c->min_io_size);
	ubifs_assert(wbuf->size <= c->max_write_size);
	ubifs_assert(wbuf->size % c->min_io_size == 0);
	ubifs_assert(mutex_is_locked(&wbuf->io_mutex));
	ubifs_assert(!c->ro_media && !c->ro_mount);
	ubifs_assert(!c->space_fixup);
	if (c->leb_size - wbuf->offs >= c->max_write_size)
		ubifs_assert(!((wbuf->offs + wbuf->size) % c->max_write_size));

	if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
		err = -ENOSPC;
		goto out;
	}

	cancel_wbuf_timer_nolock(wbuf);

	if (c->ro_error)
		return -EROFS;

	if (aligned_len <= wbuf->avail) {
		/*
		 * The node is not very large and fits entirely within
		 * write-buffer.
		 */
		memcpy(wbuf->buf + wbuf->used, buf, len);

		if (aligned_len == wbuf->avail) {
			dbg_io("flush jhead %s wbuf to LEB %d:%d",
			       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
#if defined(FEATURE_UBIFS_PERF_INDEX)
			if(wbuf->jhead == DATAHD)
				err = ubifs_leb_write_log(c, wbuf->lnum, wbuf->buf, 
						wbuf->offs, wbuf->size);
			else
#endif
			err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf,
					      wbuf->offs, wbuf->size);
			if (err)
				goto out;
			wbuf->w_count += wbuf->size; //MTK

			spin_lock(&wbuf->lock);
			wbuf->offs += wbuf->size;
			if (c->leb_size - wbuf->offs >= c->max_write_size)
				wbuf->size = c->max_write_size;
			else
				wbuf->size = c->leb_size - wbuf->offs;
			wbuf->avail = wbuf->size;
			wbuf->used = 0;
			wbuf->next_ino = 0;
			spin_unlock(&wbuf->lock);
		} else {
			spin_lock(&wbuf->lock);
			wbuf->avail -= aligned_len;
			wbuf->used += aligned_len;
			spin_unlock(&wbuf->lock);
		}

		goto exit;
	}

	written = 0;

	if (wbuf->used) {
		/*
		 * The node is large enough and does not fit entirely within
		 * current available space. We have to fill and flush
		 * write-buffer and switch to the next max. write unit.
		 */
		dbg_io("flush jhead %s wbuf to LEB %d:%d",
		       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
		memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
#if defined(FEATURE_UBIFS_PERF_INDEX)
	if(wbuf->jhead == DATAHD)
		err = ubifs_leb_write_log(c, wbuf->lnum, wbuf->buf, wbuf->offs, 
			                  wbuf->size);
	else
#endif
		err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs,
				      wbuf->size);
		if (err)
			goto out;
		wbuf->w_count += wbuf->size; //MTK

		wbuf->offs += wbuf->size;
		len -= wbuf->avail;
		aligned_len -= wbuf->avail;
		written += wbuf->avail;
	} else if (wbuf->offs & (c->max_write_size - 1)) {
		/*
		 * The write-buffer offset is not aligned to
		 * @c->max_write_size and @wbuf->size is less than
		 * @c->max_write_size. Write @wbuf->size bytes to make sure the
		 * following writes are done in optimal @c->max_write_size
		 * chunks.
		 */
		dbg_io("write %d bytes to LEB %d:%d",
		       wbuf->size, wbuf->lnum, wbuf->offs);
#if defined(FEATURE_UBIFS_PERF_INDEX)
	if(wbuf->jhead == DATAHD)
		err = ubifs_leb_write_log(c, wbuf->lnum, wbuf->buf, wbuf->offs, 
			                  wbuf->size);
	else
#endif
		err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs,
				      wbuf->size);
		if (err)
			goto out;
		wbuf->w_count += wbuf->size; //MTK

		wbuf->offs += wbuf->size;
		len -= wbuf->size;
		aligned_len -= wbuf->size;
		written += wbuf->size;
	}

	/*
	 * The remaining data may take more whole max. write units, so write the
	 * remains multiple to max. write unit size directly to the flash media.
	 * We align node length to 8-byte boundary because we anyway flash wbuf
	 * if the remaining space is less than 8 bytes.
	 */
	n = aligned_len >> c->max_write_shift;
	if (n) {
		n <<= c->max_write_shift;
		dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,
		       wbuf->offs);
#if defined(FEATURE_UBIFS_PERF_INDEX)
	if(wbuf->jhead == DATAHD)
		err = ubifs_leb_write_log(c, wbuf->lnum, buf + written,
				          wbuf->offs, n);
	else
#endif
		err = ubifs_leb_write(c, wbuf->lnum, buf + written,
				      wbuf->offs, n);
		if (err)
			goto out;
		wbuf->w_count += n; //MTK
		wbuf->offs += n;
		aligned_len -= n;
		len -= n;
		written += n;
	}

	spin_lock(&wbuf->lock);
	if (aligned_len)
		/*
		 * And now we have what's left and what does not take whole
		 * max. write unit, so write it to the write-buffer and we are
		 * done.
		 */
		memcpy(wbuf->buf, buf + written, len);

	if (c->leb_size - wbuf->offs >= c->max_write_size)
		wbuf->size = c->max_write_size;
	else
		wbuf->size = c->leb_size - wbuf->offs;
	wbuf->avail = wbuf->size - aligned_len;
	wbuf->used = aligned_len;
	wbuf->next_ino = 0;
	spin_unlock(&wbuf->lock);

exit:
	if (wbuf->sync_callback) {
		int free = c->leb_size - wbuf->offs - wbuf->used;

		err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
		if (err)
			goto out;
	}

	if (wbuf->used)
		new_wbuf_timer_nolock(wbuf);

	return 0;

out:
	ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
		  len, wbuf->lnum, wbuf->offs, err);
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	dbg_dump_leb(c, wbuf->lnum);
	return err;
}
Exemple #8
0
/**
 * ubifs_read_node_wbuf - read node from the media or write-buffer.
 * @wbuf: wbuf to check for un-written data
 * @buf: buffer to read to
 * @type: node type
 * @len: node length
 * @lnum: logical eraseblock number
 * @offs: offset within the logical eraseblock
 *
 * This function reads a node of known type and length, checks it and stores
 * in @buf. If the node partially or fully sits in the write-buffer, this
 * function takes data from the buffer, otherwise it reads the flash media.
 * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
 * error code in case of failure.
 */
int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
			 int lnum, int offs)
{
	const struct ubifs_info *c = wbuf->c;
	int err, rlen, overlap;
	struct ubifs_ch *ch = buf;

	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
	ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
	ubifs_assert(!(offs & 7) && offs < c->leb_size);
	ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);

	spin_lock(&wbuf->lock);
	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
	if (!overlap) {
		/* We may safely unlock the write-buffer and read the data */
		spin_unlock(&wbuf->lock);
		return ubifs_read_node(c, buf, type, len, lnum, offs);
	}

	/* Don't read under wbuf */
	rlen = wbuf->offs - offs;
	if (rlen < 0)
		rlen = 0;

	/* Copy the rest from the write-buffer */
	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
	spin_unlock(&wbuf->lock);

	if (rlen > 0) {
		/* Read everything that goes before write-buffer */
		err = ubi_read(c->ubi, lnum, buf, offs, rlen);
		if (err && err != -EBADMSG) {
			ubifs_err("failed to read node %d from LEB %d:%d, "
				  "error %d", type, lnum, offs, err);
			dbg_dump_stack();
			return err;
		}
	}

	if (type != ch->node_type) {
		ubifs_err("bad node type (%d but expected %d)",
			  ch->node_type, type);
		goto out;
	}

	err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
	if (err) {
		ubifs_err("expected node type %d", type);
		return err;
	}

	rlen = le32_to_cpu(ch->len);
	if (rlen != len) {
		ubifs_err("bad node length %d, expected %d", rlen, len);
		goto out;
	}

	return 0;

out:
	ubifs_err("bad node at LEB %d:%d", lnum, offs);
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	return -EINVAL;
}
Exemple #9
0
/**
 * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
 * @wbuf: write-buffer
 * @buf: node to write
 * @len: node length
 *
 * This function writes data to flash via write-buffer @wbuf. This means that
 * the last piece of the node won't reach the flash media immediately if it
 * does not take whole minimal I/O unit. Instead, the node will sit in RAM
 * until the write-buffer is synchronized (e.g., by timer).
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure. If the node cannot be written because there is no more
 * space in this logical eraseblock, %-ENOSPC is returned.
 */
int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
{
	struct ubifs_info *c = wbuf->c;
	int err, written, n, aligned_len = ALIGN(len, 8), offs;

	dbg_io("%d bytes (%s) to wbuf at LEB %d:%d", len,
	       dbg_ntype(((struct ubifs_ch *)buf)->node_type), wbuf->lnum,
	       wbuf->offs + wbuf->used);
	ubifs_assert(len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
	ubifs_assert(wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
	ubifs_assert(!(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
	ubifs_assert(wbuf->avail > 0 && wbuf->avail <= c->min_io_size);
	ubifs_assert(mutex_is_locked(&wbuf->io_mutex));

	if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
		err = -ENOSPC;
		goto out;
	}

	cancel_wbuf_timer_nolock(wbuf);

	if (c->ro_media)
		return -EROFS;

	if (aligned_len <= wbuf->avail) {
		/*
		 * The node is not very large and fits entirely within
		 * write-buffer.
		 */
		memcpy(wbuf->buf + wbuf->used, buf, len);

		if (aligned_len == wbuf->avail) {
			dbg_io("flush wbuf to LEB %d:%d", wbuf->lnum,
				wbuf->offs);
			err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf,
					    wbuf->offs, c->min_io_size,
					    wbuf->dtype);
			if (err)
				goto out;

			spin_lock(&wbuf->lock);
			wbuf->offs += c->min_io_size;
			wbuf->avail = c->min_io_size;
			wbuf->used = 0;
			wbuf->next_ino = 0;
			spin_unlock(&wbuf->lock);
		} else {
			spin_lock(&wbuf->lock);
			wbuf->avail -= aligned_len;
			wbuf->used += aligned_len;
			spin_unlock(&wbuf->lock);
		}

		goto exit;
	}

	/*
	 * The node is large enough and does not fit entirely within current
	 * minimal I/O unit. We have to fill and flush write-buffer and switch
	 * to the next min. I/O unit.
	 */
	dbg_io("flush wbuf to LEB %d:%d", wbuf->lnum, wbuf->offs);
	memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
	err = ubi_leb_write(c->ubi, wbuf->lnum, wbuf->buf, wbuf->offs,
			    c->min_io_size, wbuf->dtype);
	if (err)
		goto out;

	offs = wbuf->offs + c->min_io_size;
	len -= wbuf->avail;
	aligned_len -= wbuf->avail;
	written = wbuf->avail;

	/*
	 * The remaining data may take more whole min. I/O units, so write the
	 * remains multiple to min. I/O unit size directly to the flash media.
	 * We align node length to 8-byte boundary because we anyway flash wbuf
	 * if the remaining space is less than 8 bytes.
	 */
	n = aligned_len >> c->min_io_shift;
	if (n) {
		n <<= c->min_io_shift;
		dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum, offs);
		err = ubi_leb_write(c->ubi, wbuf->lnum, buf + written, offs, n,
				    wbuf->dtype);
		if (err)
			goto out;
		offs += n;
		aligned_len -= n;
		len -= n;
		written += n;
	}

	spin_lock(&wbuf->lock);
	if (aligned_len)
		/*
		 * And now we have what's left and what does not take whole
		 * min. I/O unit, so write it to the write-buffer and we are
		 * done.
		 */
		memcpy(wbuf->buf, buf + written, len);

	wbuf->offs = offs;
	wbuf->used = aligned_len;
	wbuf->avail = c->min_io_size - aligned_len;
	wbuf->next_ino = 0;
	spin_unlock(&wbuf->lock);

exit:
	if (wbuf->sync_callback) {
		int free = c->leb_size - wbuf->offs - wbuf->used;

		err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
		if (err)
			goto out;
	}

	if (wbuf->used)
		new_wbuf_timer_nolock(wbuf);

	return 0;

out:
	ubifs_err("cannot write %d bytes to LEB %d:%d, error %d",
		  len, wbuf->lnum, wbuf->offs, err);
	dbg_dump_node(c, buf);
	dbg_dump_stack();
	dbg_dump_leb(c, wbuf->lnum);
	return err;
}