[PATCH 12/20 take 4] UBI: update functionality

Artem Bityutskiy
2007-03-23T16:51:10Z

[-- Attachment #1: Type: text/plain, Size: 11030 bytes --]

diff -auNrp tmp-from/drivers/mtd/ubi/upd.c tmp-to/drivers/mtd/ubi/upd.c
--- tmp-from/drivers/mtd/ubi/upd.c 1970-01-01 02:00:00.000000000 +0200
+++ tmp-to/drivers/mtd/ubi/upd.c 2007-03-23 18:20:02.000000000 +0200
@@ -0,0 +1,348 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ * Copyright (c) Nokia Corporation, 2006
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ *
+ * Jan 2007: Alexander Schmidt, hacked per-volume update.
+ */
+
+/*
+ * This file contains implementation of the volume update functionality.
+ *
+ * The update operation is based on the per-volume update marker which is
+ * stored in the volume table. The update marker is set before the update
+ * starts, and removed after the update has been finished. So if the update was
+ * interrupted by an unclean re-boot or due to some other reasons, the update
+ * marker stays on the flash media and UBI finds it when it attaches the MTD
+ * device next time. If the update marker is set for a volume, the volume is
+ * treated as damaged and most I/O operations are prohibited. Only a new update
+ * operation is allowed.
+ *
+ * Note, in general it is possible to implement the update operation as a
+ * transaction with a roll-back capability.
+ */
+
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+#include "ubi.h"
+
+/**
+ * set_update_marker - set update marker.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ *
+ * This function sets the update marker flag for volume @vol_id. Returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+static int set_update_marker(struct ubi_device *ubi, int vol_id)
+{
+ int err;
+ struct ubi_vtbl_record vtbl_rec;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+
+ dbg_msg("set update marker for volume %d", vol_id);
+
+ if (vol->upd_marker) {
+ ubi_assert(ubi->vtbl[vol_id].upd_marker);
+ dbg_msg("already set");
+ return 0;
+ }
+
+ memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
+ vtbl_rec.upd_marker = 1;
+
+ err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
+ vol->upd_marker = 1;
+ return err;
+}
+
+/**
+ * clear_update_marker - clear update marker.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @bytes: new data size in bytes
+ *
+ * This function clears the update marker for volume @vol_id, sets new volume
+ * data size and clears the "corrupted" flag (static volumes only). Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static int clear_update_marker(struct ubi_device *ubi, int vol_id, long long bytes)
+{
+ int err;
+ uint64_t tmp;
+ struct ubi_vtbl_record vtbl_rec;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+
+ dbg_msg("clear update marker for volume %d", vol_id);
+
+ memcpy(&vtbl_rec, &ubi->vtbl[vol_id], sizeof(struct ubi_vtbl_record));
+ ubi_assert(vol->upd_marker && vtbl_rec.upd_marker);
+ vtbl_rec.upd_marker = 0;
+
+ if (vol->vol_type == UBI_STATIC_VOLUME) {
+ vol->corrupted = 0;
+ vol->used_bytes = tmp = bytes;
+ vol->last_eb_bytes = do_div(tmp, vol->usable_leb_size);
+ vol->used_ebs = tmp;
+ if (vol->last_eb_bytes)
+ vol->used_ebs += 1;
+ else
+ vol->last_eb_bytes = vol->usable_leb_size;
+ }
+
+ err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
+ vol->upd_marker = 0;
+ return err;
+}
+
+/**
+ * ubi_start_update - start volume update.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @bytes: update bytes
+ *
+ * This function starts volume update operation. If @bytes is zero, the volume
+ * is just wiped out. Returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+int ubi_start_update(struct ubi_device *ubi, int vol_id, long long bytes)
+{
+ int i, err;
+ uint64_t tmp;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+
+ dbg_msg("start update of volume %d, %llu bytes", vol_id, bytes);
+ vol->updating = 1;
+
+ err = set_update_marker(ubi, vol_id);
+ if (err)
+ return err;
+
+ /* Before updating - wipe out the volume */
+ for (i = 0; i < vol->reserved_pebs; i++) {
+ err = ubi_eba_unmap_leb(ubi, vol_id, i);
+ if (err)
+ return err;
+ }
+
+ if (bytes == 0) {
+ err = clear_update_marker(ubi, vol_id, 0);
+ if (err)
+ return err;
+ err = ubi_wl_flush(ubi);
+ if (!err)
+ vol->updating = 0;
+ }
+
+ vol->upd_buf = kmalloc(ubi->leb_size, GFP_KERNEL);
+ if (!vol->upd_buf)
+ return -ENOMEM;
+
+ tmp = bytes;
+ vol->upd_ebs = !!do_div(tmp, vol->usable_leb_size);
+ vol->upd_ebs += tmp;
+ vol->upd_bytes = bytes;
+ vol->upd_received = 0;
+ return 0;
+}
+
+/**
+ * write_leb - write update data.
+ * @ubi: UBI device description object
+ * @vol_id: volume ID
+ * @lnum: logical eraseblock number
+ * @buf: data to write
+ * @len: data size
+ * @used_ebs: how many logical eraseblocks will this volume contain (static
+ * volumes only)
+ *
+ * This function writes update data to corresponding logical eraseblock. In
+ * case of dynamic volume, this function checks if the data contains 0xFF bytes
+ * at the end. If yes, the 0xFF bytes are cut and not written. So if the whole
+ * buffer contains only 0xFF bytes, the LEB is left unmapped.
+ *
+ * The reason why we skip the trailing 0xFF bytes in case of dynamic volume is
+ * that we want to make sure that more data may be appended to the logical
+ * eraseblock in future. Indeed, writing 0xFF bytes may have side effects and
+ * this PEB won't be writable anymore. So if one writes the file-system image
+ * to the UBI volume where 0xFFs mean free space - UBI makes sure this free
+ * space is writable after the update.
+ *
+ * We do not do this for static volumes because they are read-only. But this
+ * also cannot be done because we have to store per-LEB CRC and the correct
+ * data length.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int write_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
+ int len, int used_ebs)
+{
+ int err, l;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+
+ if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
+ l = ubi_align_up(len, ubi->min_io_size);
+ memset(buf + len, 0xFF, l - len);
+
+ l = ubi_calc_data_len(ubi, buf, l);
+ if (l == 0) {
+ dbg_msg("all %d bytes contain 0xFF - skip", len);
+ return 0;
+ }
+ if (len != l)
+ dbg_msg("skip last %d bytes (0xFF)", len - l);
+
+ err = ubi_eba_write_leb(ubi, vol_id, lnum, buf, 0, l,
+ UBI_DATA_UNKNOWN);
+ } else {
+ /*
+ * When writing static volume, and this is the last logical
+ * eraseblock, the length (@len) does not have to be aligned to
+ * the minimal flash I/O unit. The 'ubi_eba_write_leb_st()'
+ * function accepts exact (unaligned) length and stores it in
+ * the VID header. And it takes care of proper alignment by
+ * padding the buffer. Here we just make sure the padding will
+ * contain zeros, not random trash.
+ */
+ memset(buf + len, 0, vol->usable_leb_size - len);
+ err = ubi_eba_write_leb_st(ubi, vol_id, lnum, buf, len,
+ UBI_DATA_UNKNOWN, used_ebs);
+ }
+
+ return err;
+}
+
+/**
+ * ubi_more_update_data - write more update data.
+ * @vol: volume description object
+ * @buf: write data (user-space memory buffer)
+ * @count: how much bytes to write
+ *
+ * This function writes more data to the volume which is being updated. It may
+ * be called arbitrary number of times until all of the update data arrive.
+ * This function returns %0 in case of success, number of bytes written during
+ * the last call if the whole volume update was successfully finished, and a
+ * negative error code in case of failure.
+ */
+int ubi_more_update_data(struct ubi_device *ubi, int vol_id,
+ const void __user *buf, int count)
+{
+ uint64_t tmp;
+ struct ubi_volume *vol = ubi->volumes[vol_id];
+ int lnum, offs, err = 0, len, to_write = count;
+
+ dbg_msg("write %d of %lld bytes, %lld already passed",
+ count, vol->upd_bytes, vol->upd_received);
+
+ if (unlikely(ubi->ro_mode))
+ return -EROFS;
+
+ tmp = vol->upd_received;
+ offs = do_div(tmp, vol->usable_leb_size);
+ lnum = tmp;
+
+ if (vol->upd_received + count > vol->upd_bytes)
+ to_write = count = vol->upd_bytes - vol->upd_received;
+
+ /*
+ * When updating volumes, we accumulate whole logical eraseblock of
+ * data and write it at once.
+ */
+ if (offs != 0) {
+ /*
+ * This is a write to the middle of the logical eraseblock. We
+ * copy the data to our update buffer and wait for more data or
+ * flush it if the whole eraseblock is written or the update
+ * is finished.
+ */
+
+ len = vol->usable_leb_size - offs;
+ if (len > count)
+ len = count;
+
+ err = copy_from_user(vol->upd_buf + offs, buf, len);
+ if (unlikely(err))
+ return -EFAULT;
+
+ if (offs + len == vol->usable_leb_size ||
+ vol->upd_received + len == vol->upd_bytes) {
+ int flush_len = offs + len;
+
+ /*
+ * OK, we gathered either the whole eraseblock or this
+ * is the last chunk, it's time to flush the buffer.
+ */
+ ubi_assert(flush_len <= vol->usable_leb_size);
+ err = write_leb(ubi, vol_id, lnum, vol->upd_buf,
+ flush_len, vol->upd_ebs);
+ if (err)
+ return err;
+ }
+
+ vol->upd_received += len;
+ count -= len;
+ buf += len;
+ lnum += 1;
+ }
+
+ /*
+ * If we've got more to write, let's continue. At this point we know we
+ * are starting from the beginning of an eraseblock.
+ */
+ while (count) {
+ if (count > vol->usable_leb_size)
+ len = vol->usable_leb_size;
+ else
+ len = count;
+
+ err = copy_from_user(vol->upd_buf, buf, len);
+ if (unlikely(err))
+ return -EFAULT;
+
+ if (len == vol->usable_leb_size ||
+ vol->upd_received + len == vol->upd_bytes) {
+ err = write_leb(ubi, vol_id, lnum, vol->upd_buf, len,
+ vol->upd_ebs);
+ if (unlikely(err))
+ break;
+ }
+
+ vol->upd_received += len;
+ count -= len;
+ lnum += 1;
+ buf += len;
+ }
+
+ ubi_assert(vol->upd_received <= vol->upd_bytes);
+ if (vol->upd_received == vol->upd_bytes) {
+ /* The update is finished, clear the update marker */
+ err = clear_update_marker(ubi, vol_id, vol->upd_bytes);
+ if (err)
+ return err;
+ err = ubi_wl_flush(ubi);
+ if (err == 0) {
+ err = to_write;
+ kfree(vol->upd_buf);
+ vol->updating = 0;
+ }
+ }
+
+ return err;
+}