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Diffstat (limited to '')
| -rw-r--r-- | drivers/mtd/ubi/upd.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c new file mode 100644 index 000000000..962f693cf --- /dev/null +++ b/drivers/mtd/ubi/upd.c @@ -0,0 +1,420 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) International Business Machines Corp., 2006 + * Copyright (c) Nokia Corporation, 2006 + * + * 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. + */ + +#include <linux/err.h> +#include <linux/uaccess.h> +#include <linux/math64.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_gen("set update marker for volume %d", vol->vol_id); + + if (vol->upd_marker) { + ubi_assert(ubi->vtbl[vol->vol_id].upd_marker); + dbg_gen("already set"); + return 0; + } + + vtbl_rec = ubi->vtbl[vol->vol_id]; + vtbl_rec.upd_marker = 1; + + mutex_lock(&ubi->device_mutex); + err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); + vol->upd_marker = 1; + mutex_unlock(&ubi->device_mutex); + 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; + struct ubi_vtbl_record vtbl_rec; + + dbg_gen("clear update marker for volume %d", vol->vol_id); + + vtbl_rec = ubi->vtbl[vol->vol_id]; + 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 = bytes; + vol->used_ebs = div_u64_rem(bytes, vol->usable_leb_size, + &vol->last_eb_bytes); + if (vol->last_eb_bytes) + vol->used_ebs += 1; + else + vol->last_eb_bytes = vol->usable_leb_size; + } + + mutex_lock(&ubi->device_mutex); + err = ubi_change_vtbl_record(ubi, vol->vol_id, &vtbl_rec); + vol->upd_marker = 0; + mutex_unlock(&ubi->device_mutex); + 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; + + dbg_gen("start update of volume %d, %llu bytes", vol->vol_id, bytes); + ubi_assert(!vol->updating && !vol->changing_leb); + vol->updating = 1; + + vol->upd_buf = vmalloc(ubi->leb_size); + if (!vol->upd_buf) + return -ENOMEM; + + 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; + } + + err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); + if (err) + return err; + + if (bytes == 0) { + err = clear_update_marker(ubi, vol, 0); + if (err) + return err; + + vfree(vol->upd_buf); + vol->updating = 0; + return 0; + } + + vol->upd_ebs = div_u64(bytes + vol->usable_leb_size - 1, + vol->usable_leb_size); + 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_gen("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); + + vol->upd_bytes = req->bytes; + vol->upd_received = 0; + vol->changing_leb = 1; + vol->ch_lnum = req->lnum; + + vol->upd_buf = vmalloc(ALIGN((int)req->bytes, ubi->min_io_size)); + 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_gen("all %d bytes contain 0xFF - skip", len); + return 0; + } + + err = ubi_eba_write_leb(ubi, vol, lnum, buf, 0, len); + } 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, used_ebs); + } + + return err; +} + +/** + * ubi_more_update_data - write more update data. + * @ubi: UBI device description object + * @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) +{ + int lnum, offs, err = 0, len, to_write = count; + + dbg_gen("write %d of %lld bytes, %lld already passed", + count, vol->upd_bytes, vol->upd_received); + + if (ubi->ro_mode) + return -EROFS; + + lnum = div_u64_rem(vol->upd_received, vol->usable_leb_size, &offs); + 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) { + err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL); + if (err) + return err; + /* The update is finished, clear the update marker */ + err = clear_update_marker(ubi, vol, vol->upd_bytes); + if (err) + return err; + vol->updating = 0; + err = to_write; + vfree(vol->upd_buf); + } + + return err; +} + +/** + * ubi_more_leb_change_data - accept more data for atomic LEB change. + * @ubi: UBI device description object + * @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_gen("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); + 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; +} |