/* * 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 #include #include #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 = 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; } /** * 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 = ALIGN(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_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_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 (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_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 (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 (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; vfree(vol->upd_buf); vol->updating = 0; } } return err; }