--- /dev/null
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ * Copyright (c) Nokia Corporation, 2006
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ *
+ * Jan 2007: Alexander Schmidt, hacked per-volume update.
+ */
+
+/*
+ * This file contains implementation of the volume update and atomic LEB change
+ * 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.
+ */
+
+#ifdef UBI_LINUX
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+#endif
+
+#include <ubi_uboot.h>
+#include "ubi.h"
+
+/**
+ * set_update_marker - set update marker.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ *
+ * This function sets the update marker flag for volume @vol. Returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+static int set_update_marker(struct ubi_device *ubi, struct ubi_volume *vol)
+{
+ int err;
+ struct ubi_vtbl_record vtbl_rec;
+
+ dbg_msg("set update marker for volume %d", vol->vol_id);
+
+ if (vol->upd_marker) {
+ ubi_assert(ubi->vtbl[vol->vol_id].upd_marker);
+ dbg_msg("already set");
+ return 0;
+ }
+
+ memcpy(&vtbl_rec, &ubi->vtbl[vol->vol_id],
+ sizeof(struct ubi_vtbl_record));
+ vtbl_rec.upd_marker = 1;
+
+ mutex_lock(&ubi->volumes_mutex);
+ err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
+ mutex_unlock(&ubi->volumes_mutex);
+ vol->upd_marker = 1;
+ return err;
+}
+
+/**
+ * clear_update_marker - clear update marker.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @bytes: new data size in bytes
+ *
+ * This function clears the update marker for volume @vol, 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, struct ubi_volume *vol,
+ long long bytes)
+{
+ int err;
+ uint64_t tmp;
+ struct ubi_vtbl_record vtbl_rec;
+
+ dbg_msg("clear update marker for volume %d", vol->vol_id);
+
+ memcpy(&vtbl_rec, &ubi->vtbl[vol->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;
+ }
+
+ mutex_lock(&ubi->volumes_mutex);
+ err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec);
+ mutex_unlock(&ubi->volumes_mutex);
+ vol->upd_marker = 0;
+ return err;
+}
+
+/**
+ * ubi_start_update - start volume update.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @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, struct ubi_volume *vol,
+ long long bytes)
+{
+ int i, err;
+ uint64_t tmp;
+
+ dbg_msg("start update of volume %d, %llu bytes", vol->vol_id, bytes);
+ ubi_assert(!vol->updating && !vol->changing_leb);
+ vol->updating = 1;
+
+ err = set_update_marker(ubi, vol);
+ 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, i);
+ if (err)
+ return err;
+ }
+
+ if (bytes == 0) {
+ err = clear_update_marker(ubi, vol, 0);
+ if (err)
+ return err;
+ err = ubi_wl_flush(ubi);
+ if (!err)
+ vol->updating = 0;
+ }
+
+ vol->upd_buf = vmalloc(ubi->leb_size);
+ 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;
+}
+
+/**
+ * ubi_start_leb_change - start atomic LEB change.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @req: operation request
+ *
+ * This function starts atomic LEB change operation. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
+ const struct ubi_leb_change_req *req)
+{
+ ubi_assert(!vol->updating && !vol->changing_leb);
+
+ dbg_msg("start changing LEB %d:%d, %u bytes",
+ vol->vol_id, req->lnum, req->bytes);
+ if (req->bytes == 0)
+ return ubi_eba_atomic_leb_change(ubi, vol, req->lnum, NULL, 0,
+ req->dtype);
+
+ vol->upd_bytes = req->bytes;
+ vol->upd_received = 0;
+ vol->changing_leb = 1;
+ vol->ch_lnum = req->lnum;
+ vol->ch_dtype = req->dtype;
+
+ vol->upd_buf = vmalloc(req->bytes);
+ if (!vol->upd_buf)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/**
+ * write_leb - write update data.
+ * @ubi: UBI device description object
+ * @vol: volume description object
+ * @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, struct ubi_volume *vol, int lnum,
+ void *buf, int len, int used_ebs)
+{
+ int err;
+
+ if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
+ int l = ALIGN(len, ubi->min_io_size);
+
+ memset(buf + len, 0xFF, l - len);
+ len = ubi_calc_data_len(ubi, buf, l);
+ if (len == 0) {
+ dbg_msg("all %d bytes contain 0xFF - skip", len);
+ return 0;
+ }
+
+ err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len, UBI_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, lnum, buf, len,
+ UBI_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 the update data arriveis. This
+ * function returns %0 in case of success, number of bytes written during the
+ * last call if the whole volume update has been successfully finished, and a
+ * negative error code in case of failure.
+ */
+int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
+ const void __user *buf, int count)
+{
+ uint64_t tmp;
+ 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 (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 (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, 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 (err)
+ return -EFAULT;
+
+ if (len == vol->usable_leb_size ||
+ vol->upd_received + len == vol->upd_bytes) {
+ err = write_leb(ubi, vol, lnum, vol->upd_buf,
+ len, vol->upd_ebs);
+ if (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, vol->upd_bytes);
+ if (err)
+ return err;
+ err = ubi_wl_flush(ubi);
+ if (err == 0) {
+ vol->updating = 0;
+ err = to_write;
+ vfree(vol->upd_buf);
+ }
+ }
+
+ return err;
+}
+
+/**
+ * ubi_more_leb_change_data - accept more data for atomic LEB change.
+ * @vol: volume description object
+ * @buf: write data (user-space memory buffer)
+ * @count: how much bytes to write
+ *
+ * This function accepts more data to the volume which is being under the
+ * "atomic LEB change" operation. It may be called arbitrary number of times
+ * until all data arrives. This function returns %0 in case of success, number
+ * of bytes written during the last call if the whole "atomic LEB change"
+ * operation has been successfully finished, and a negative error code in case
+ * of failure.
+ */
+int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
+ const void __user *buf, int count)
+{
+ int err;
+
+ dbg_msg("write %d of %lld bytes, %lld already passed",
+ count, vol->upd_bytes, vol->upd_received);
+
+ if (ubi->ro_mode)
+ return -EROFS;
+
+ if (vol->upd_received + count > vol->upd_bytes)
+ count = vol->upd_bytes - vol->upd_received;
+
+ err = copy_from_user(vol->upd_buf + vol->upd_received, buf, count);
+ if (err)
+ return -EFAULT;
+
+ vol->upd_received += count;
+
+ if (vol->upd_received == vol->upd_bytes) {
+ int len = ALIGN((int)vol->upd_bytes, ubi->min_io_size);
+
+ memset(vol->upd_buf + vol->upd_bytes, 0xFF, len - vol->upd_bytes);
+ len = ubi_calc_data_len(ubi, vol->upd_buf, len);
+ err = ubi_eba_atomic_leb_change(ubi, vol, vol->ch_lnum,
+ vol->upd_buf, len, UBI_UNKNOWN);
+ if (err)
+ return err;
+ }
+
+ ubi_assert(vol->upd_received <= vol->upd_bytes);
+ if (vol->upd_received == vol->upd_bytes) {
+ vol->changing_leb = 0;
+ err = count;
+ vfree(vol->upd_buf);
+ }
+
+ return err;
+}
Code Review / kvmfornfv.git / blobdiff