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Diffstat (limited to 'drivers/mtd/ubi/eba.c')
| -rw-r--r-- | drivers/mtd/ubi/eba.c | 1477 |
1 files changed, 1477 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c new file mode 100644 index 000000000..51bca035c --- /dev/null +++ b/drivers/mtd/ubi/eba.c @@ -0,0 +1,1477 @@ +/* + * Copyright (c) International Business Machines Corp., 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) + */ + +/* + * The UBI Eraseblock Association (EBA) sub-system. + * + * This sub-system is responsible for I/O to/from logical eraseblock. + * + * Although in this implementation the EBA table is fully kept and managed in + * RAM, which assumes poor scalability, it might be (partially) maintained on + * flash in future implementations. + * + * The EBA sub-system implements per-logical eraseblock locking. Before + * accessing a logical eraseblock it is locked for reading or writing. The + * per-logical eraseblock locking is implemented by means of the lock tree. The + * lock tree is an RB-tree which refers all the currently locked logical + * eraseblocks. The lock tree elements are &struct ubi_ltree_entry objects. + * They are indexed by (@vol_id, @lnum) pairs. + * + * EBA also maintains the global sequence counter which is incremented each + * time a logical eraseblock is mapped to a physical eraseblock and it is + * stored in the volume identifier header. This means that each VID header has + * a unique sequence number. The sequence number is only increased an we assume + * 64 bits is enough to never overflow. + */ + +#include <linux/slab.h> +#include <linux/crc32.h> +#include <linux/err.h> +#include "ubi.h" + +/* Number of physical eraseblocks reserved for atomic LEB change operation */ +#define EBA_RESERVED_PEBS 1 + +/** + * next_sqnum - get next sequence number. + * @ubi: UBI device description object + * + * This function returns next sequence number to use, which is just the current + * global sequence counter value. It also increases the global sequence + * counter. + */ +unsigned long long ubi_next_sqnum(struct ubi_device *ubi) +{ + unsigned long long sqnum; + + spin_lock(&ubi->ltree_lock); + sqnum = ubi->global_sqnum++; + spin_unlock(&ubi->ltree_lock); + + return sqnum; +} + +/** + * ubi_get_compat - get compatibility flags of a volume. + * @ubi: UBI device description object + * @vol_id: volume ID + * + * This function returns compatibility flags for an internal volume. User + * volumes have no compatibility flags, so %0 is returned. + */ +static int ubi_get_compat(const struct ubi_device *ubi, int vol_id) +{ + if (vol_id == UBI_LAYOUT_VOLUME_ID) + return UBI_LAYOUT_VOLUME_COMPAT; + return 0; +} + +/** + * ltree_lookup - look up the lock tree. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + * + * This function returns a pointer to the corresponding &struct ubi_ltree_entry + * object if the logical eraseblock is locked and %NULL if it is not. + * @ubi->ltree_lock has to be locked. + */ +static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id, + int lnum) +{ + struct rb_node *p; + + p = ubi->ltree.rb_node; + while (p) { + struct ubi_ltree_entry *le; + + le = rb_entry(p, struct ubi_ltree_entry, rb); + + if (vol_id < le->vol_id) + p = p->rb_left; + else if (vol_id > le->vol_id) + p = p->rb_right; + else { + if (lnum < le->lnum) + p = p->rb_left; + else if (lnum > le->lnum) + p = p->rb_right; + else + return le; + } + } + + return NULL; +} + +/** + * ltree_add_entry - add new entry to the lock tree. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + * + * This function adds new entry for logical eraseblock (@vol_id, @lnum) to the + * lock tree. If such entry is already there, its usage counter is increased. + * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation + * failed. + */ +static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi, + int vol_id, int lnum) +{ + struct ubi_ltree_entry *le, *le1, *le_free; + + le = kmalloc(sizeof(struct ubi_ltree_entry), GFP_NOFS); + if (!le) + return ERR_PTR(-ENOMEM); + + le->users = 0; + init_rwsem(&le->mutex); + le->vol_id = vol_id; + le->lnum = lnum; + + spin_lock(&ubi->ltree_lock); + le1 = ltree_lookup(ubi, vol_id, lnum); + + if (le1) { + /* + * This logical eraseblock is already locked. The newly + * allocated lock entry is not needed. + */ + le_free = le; + le = le1; + } else { + struct rb_node **p, *parent = NULL; + + /* + * No lock entry, add the newly allocated one to the + * @ubi->ltree RB-tree. + */ + le_free = NULL; + + p = &ubi->ltree.rb_node; + while (*p) { + parent = *p; + le1 = rb_entry(parent, struct ubi_ltree_entry, rb); + + if (vol_id < le1->vol_id) + p = &(*p)->rb_left; + else if (vol_id > le1->vol_id) + p = &(*p)->rb_right; + else { + ubi_assert(lnum != le1->lnum); + if (lnum < le1->lnum) + p = &(*p)->rb_left; + else + p = &(*p)->rb_right; + } + } + + rb_link_node(&le->rb, parent, p); + rb_insert_color(&le->rb, &ubi->ltree); + } + le->users += 1; + spin_unlock(&ubi->ltree_lock); + + kfree(le_free); + return le; +} + +/** + * leb_read_lock - lock logical eraseblock for reading. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + * + * This function locks a logical eraseblock for reading. Returns zero in case + * of success and a negative error code in case of failure. + */ +static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum) +{ + struct ubi_ltree_entry *le; + + le = ltree_add_entry(ubi, vol_id, lnum); + if (IS_ERR(le)) + return PTR_ERR(le); + down_read(&le->mutex); + return 0; +} + +/** + * leb_read_unlock - unlock logical eraseblock. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + */ +static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum) +{ + struct ubi_ltree_entry *le; + + spin_lock(&ubi->ltree_lock); + le = ltree_lookup(ubi, vol_id, lnum); + le->users -= 1; + ubi_assert(le->users >= 0); + up_read(&le->mutex); + if (le->users == 0) { + rb_erase(&le->rb, &ubi->ltree); + kfree(le); + } + spin_unlock(&ubi->ltree_lock); +} + +/** + * leb_write_lock - lock logical eraseblock for writing. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + * + * This function locks a logical eraseblock for writing. Returns zero in case + * of success and a negative error code in case of failure. + */ +static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum) +{ + struct ubi_ltree_entry *le; + + le = ltree_add_entry(ubi, vol_id, lnum); + if (IS_ERR(le)) + return PTR_ERR(le); + down_write(&le->mutex); + return 0; +} + +/** + * leb_write_lock - lock logical eraseblock for writing. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + * + * This function locks a logical eraseblock for writing if there is no + * contention and does nothing if there is contention. Returns %0 in case of + * success, %1 in case of contention, and and a negative error code in case of + * failure. + */ +static int leb_write_trylock(struct ubi_device *ubi, int vol_id, int lnum) +{ + struct ubi_ltree_entry *le; + + le = ltree_add_entry(ubi, vol_id, lnum); + if (IS_ERR(le)) + return PTR_ERR(le); + if (down_write_trylock(&le->mutex)) + return 0; + + /* Contention, cancel */ + spin_lock(&ubi->ltree_lock); + le->users -= 1; + ubi_assert(le->users >= 0); + if (le->users == 0) { + rb_erase(&le->rb, &ubi->ltree); + kfree(le); + } + spin_unlock(&ubi->ltree_lock); + + return 1; +} + +/** + * leb_write_unlock - unlock logical eraseblock. + * @ubi: UBI device description object + * @vol_id: volume ID + * @lnum: logical eraseblock number + */ +static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum) +{ + struct ubi_ltree_entry *le; + + spin_lock(&ubi->ltree_lock); + le = ltree_lookup(ubi, vol_id, lnum); + le->users -= 1; + ubi_assert(le->users >= 0); + up_write(&le->mutex); + if (le->users == 0) { + rb_erase(&le->rb, &ubi->ltree); + kfree(le); + } + spin_unlock(&ubi->ltree_lock); +} + +/** + * ubi_eba_unmap_leb - un-map logical eraseblock. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * + * This function un-maps logical eraseblock @lnum and schedules corresponding + * physical eraseblock for erasure. Returns zero in case of success and a + * negative error code in case of failure. + */ +int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol, + int lnum) +{ + int err, pnum, vol_id = vol->vol_id; + + if (ubi->ro_mode) + return -EROFS; + + err = leb_write_lock(ubi, vol_id, lnum); + if (err) + return err; + + pnum = vol->eba_tbl[lnum]; + if (pnum < 0) + /* This logical eraseblock is already unmapped */ + goto out_unlock; + + dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum); + + down_read(&ubi->fm_eba_sem); + vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED; + up_read(&ubi->fm_eba_sem); + err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 0); + +out_unlock: + leb_write_unlock(ubi, vol_id, lnum); + return err; +} + +/** + * ubi_eba_read_leb - read data. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @buf: buffer to store the read data + * @offset: offset from where to read + * @len: how many bytes to read + * @check: data CRC check flag + * + * If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF + * bytes. The @check flag only makes sense for static volumes and forces + * eraseblock data CRC checking. + * + * In case of success this function returns zero. In case of a static volume, + * if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be + * returned for any volume type if an ECC error was detected by the MTD device + * driver. Other negative error cored may be returned in case of other errors. + */ +int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, + void *buf, int offset, int len, int check) +{ + int err, pnum, scrub = 0, vol_id = vol->vol_id; + struct ubi_vid_hdr *vid_hdr; + uint32_t uninitialized_var(crc); + + err = leb_read_lock(ubi, vol_id, lnum); + if (err) + return err; + + pnum = vol->eba_tbl[lnum]; + if (pnum < 0) { + /* + * The logical eraseblock is not mapped, fill the whole buffer + * with 0xFF bytes. The exception is static volumes for which + * it is an error to read unmapped logical eraseblocks. + */ + dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)", + len, offset, vol_id, lnum); + leb_read_unlock(ubi, vol_id, lnum); + ubi_assert(vol->vol_type != UBI_STATIC_VOLUME); + memset(buf, 0xFF, len); + return 0; + } + + dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d", + len, offset, vol_id, lnum, pnum); + + if (vol->vol_type == UBI_DYNAMIC_VOLUME) + check = 0; + +retry: + if (check) { + vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); + if (!vid_hdr) { + err = -ENOMEM; + goto out_unlock; + } + + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1); + if (err && err != UBI_IO_BITFLIPS) { + if (err > 0) { + /* + * The header is either absent or corrupted. + * The former case means there is a bug - + * switch to read-only mode just in case. + * The latter case means a real corruption - we + * may try to recover data. FIXME: but this is + * not implemented. + */ + if (err == UBI_IO_BAD_HDR_EBADMSG || + err == UBI_IO_BAD_HDR) { + ubi_warn(ubi, "corrupted VID header at PEB %d, LEB %d:%d", + pnum, vol_id, lnum); + err = -EBADMSG; + } else { + err = -EINVAL; + ubi_ro_mode(ubi); + } + } + goto out_free; + } else if (err == UBI_IO_BITFLIPS) + scrub = 1; + + ubi_assert(lnum < be32_to_cpu(vid_hdr->used_ebs)); + ubi_assert(len == be32_to_cpu(vid_hdr->data_size)); + + crc = be32_to_cpu(vid_hdr->data_crc); + ubi_free_vid_hdr(ubi, vid_hdr); + } + + err = ubi_io_read_data(ubi, buf, pnum, offset, len); + if (err) { + if (err == UBI_IO_BITFLIPS) + scrub = 1; + else if (mtd_is_eccerr(err)) { + if (vol->vol_type == UBI_DYNAMIC_VOLUME) + goto out_unlock; + scrub = 1; + if (!check) { + ubi_msg(ubi, "force data checking"); + check = 1; + goto retry; + } + } else + goto out_unlock; + } + + if (check) { + uint32_t crc1 = crc32(UBI_CRC32_INIT, buf, len); + if (crc1 != crc) { + ubi_warn(ubi, "CRC error: calculated %#08x, must be %#08x", + crc1, crc); + err = -EBADMSG; + goto out_unlock; + } + } + + if (scrub) + err = ubi_wl_scrub_peb(ubi, pnum); + + leb_read_unlock(ubi, vol_id, lnum); + return err; + +out_free: + ubi_free_vid_hdr(ubi, vid_hdr); +out_unlock: + leb_read_unlock(ubi, vol_id, lnum); + return err; +} + +/** + * ubi_eba_read_leb_sg - read data into a scatter gather list. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @sgl: UBI scatter gather list to store the read data + * @offset: offset from where to read + * @len: how many bytes to read + * @check: data CRC check flag + * + * This function works exactly like ubi_eba_read_leb(). But instead of + * storing the read data into a buffer it writes to an UBI scatter gather + * list. + */ +int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol, + struct ubi_sgl *sgl, int lnum, int offset, int len, + int check) +{ + int to_read; + int ret; + struct scatterlist *sg; + + for (;;) { + ubi_assert(sgl->list_pos < UBI_MAX_SG_COUNT); + sg = &sgl->sg[sgl->list_pos]; + if (len < sg->length - sgl->page_pos) + to_read = len; + else + to_read = sg->length - sgl->page_pos; + + ret = ubi_eba_read_leb(ubi, vol, lnum, + sg_virt(sg) + sgl->page_pos, offset, + to_read, check); + if (ret < 0) + return ret; + + offset += to_read; + len -= to_read; + if (!len) { + sgl->page_pos += to_read; + if (sgl->page_pos == sg->length) { + sgl->list_pos++; + sgl->page_pos = 0; + } + + break; + } + + sgl->list_pos++; + sgl->page_pos = 0; + } + + return ret; +} + +/** + * recover_peb - recover from write failure. + * @ubi: UBI device description object + * @pnum: the physical eraseblock to recover + * @vol_id: volume ID + * @lnum: logical eraseblock number + * @buf: data which was not written because of the write failure + * @offset: offset of the failed write + * @len: how many bytes should have been written + * + * This function is called in case of a write failure and moves all good data + * from the potentially bad physical eraseblock to a good physical eraseblock. + * This function also writes the data which was not written due to the failure. + * Returns new physical eraseblock number in case of success, and a negative + * error code in case of failure. + */ +static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum, + const void *buf, int offset, int len) +{ + int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0; + struct ubi_volume *vol = ubi->volumes[idx]; + struct ubi_vid_hdr *vid_hdr; + + vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); + if (!vid_hdr) + return -ENOMEM; + +retry: + new_pnum = ubi_wl_get_peb(ubi); + if (new_pnum < 0) { + ubi_free_vid_hdr(ubi, vid_hdr); + up_read(&ubi->fm_eba_sem); + return new_pnum; + } + + ubi_msg(ubi, "recover PEB %d, move data to PEB %d", + pnum, new_pnum); + + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1); + if (err && err != UBI_IO_BITFLIPS) { + if (err > 0) + err = -EIO; + up_read(&ubi->fm_eba_sem); + goto out_put; + } + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr); + if (err) { + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + data_size = offset + len; + mutex_lock(&ubi->buf_mutex); + memset(ubi->peb_buf + offset, 0xFF, len); + + /* Read everything before the area where the write failure happened */ + if (offset > 0) { + err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, offset); + if (err && err != UBI_IO_BITFLIPS) { + up_read(&ubi->fm_eba_sem); + goto out_unlock; + } + } + + memcpy(ubi->peb_buf + offset, buf, len); + + err = ubi_io_write_data(ubi, ubi->peb_buf, new_pnum, 0, data_size); + if (err) { + mutex_unlock(&ubi->buf_mutex); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + mutex_unlock(&ubi->buf_mutex); + ubi_free_vid_hdr(ubi, vid_hdr); + + vol->eba_tbl[lnum] = new_pnum; + up_read(&ubi->fm_eba_sem); + ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1); + + ubi_msg(ubi, "data was successfully recovered"); + return 0; + +out_unlock: + mutex_unlock(&ubi->buf_mutex); +out_put: + ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + +write_error: + /* + * Bad luck? This physical eraseblock is bad too? Crud. Let's try to + * get another one. + */ + ubi_warn(ubi, "failed to write to PEB %d", new_pnum); + ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1); + if (++tries > UBI_IO_RETRIES) { + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + ubi_msg(ubi, "try again"); + goto retry; +} + +/** + * ubi_eba_write_leb - write data to dynamic volume. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @buf: the data to write + * @offset: offset within the logical eraseblock where to write + * @len: how many bytes to write + * + * This function writes data to logical eraseblock @lnum of a dynamic volume + * @vol. Returns zero in case of success and a negative error code in case + * of failure. In case of error, it is possible that something was still + * written to the flash media, but may be some garbage. + */ +int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum, + const void *buf, int offset, int len) +{ + int err, pnum, tries = 0, vol_id = vol->vol_id; + struct ubi_vid_hdr *vid_hdr; + + if (ubi->ro_mode) + return -EROFS; + + err = leb_write_lock(ubi, vol_id, lnum); + if (err) + return err; + + pnum = vol->eba_tbl[lnum]; + if (pnum >= 0) { + dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d", + len, offset, vol_id, lnum, pnum); + + err = ubi_io_write_data(ubi, buf, pnum, offset, len); + if (err) { + ubi_warn(ubi, "failed to write data to PEB %d", pnum); + if (err == -EIO && ubi->bad_allowed) + err = recover_peb(ubi, pnum, vol_id, lnum, buf, + offset, len); + if (err) + ubi_ro_mode(ubi); + } + leb_write_unlock(ubi, vol_id, lnum); + return err; + } + + /* + * The logical eraseblock is not mapped. We have to get a free physical + * eraseblock and write the volume identifier header there first. + */ + vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); + if (!vid_hdr) { + leb_write_unlock(ubi, vol_id, lnum); + return -ENOMEM; + } + + vid_hdr->vol_type = UBI_VID_DYNAMIC; + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + vid_hdr->vol_id = cpu_to_be32(vol_id); + vid_hdr->lnum = cpu_to_be32(lnum); + vid_hdr->compat = ubi_get_compat(ubi, vol_id); + vid_hdr->data_pad = cpu_to_be32(vol->data_pad); + +retry: + pnum = ubi_wl_get_peb(ubi); + if (pnum < 0) { + ubi_free_vid_hdr(ubi, vid_hdr); + leb_write_unlock(ubi, vol_id, lnum); + up_read(&ubi->fm_eba_sem); + return pnum; + } + + dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d", + len, offset, vol_id, lnum, pnum); + + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr); + if (err) { + ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d", + vol_id, lnum, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + if (len) { + err = ubi_io_write_data(ubi, buf, pnum, offset, len); + if (err) { + ubi_warn(ubi, "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d", + len, offset, vol_id, lnum, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + } + + vol->eba_tbl[lnum] = pnum; + up_read(&ubi->fm_eba_sem); + + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return 0; + +write_error: + if (err != -EIO || !ubi->bad_allowed) { + ubi_ro_mode(ubi); + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + + /* + * Fortunately, this is the first write operation to this physical + * eraseblock, so just put it and request a new one. We assume that if + * this physical eraseblock went bad, the erase code will handle that. + */ + err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1); + if (err || ++tries > UBI_IO_RETRIES) { + ubi_ro_mode(ubi); + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + ubi_msg(ubi, "try another PEB"); + goto retry; +} + +/** + * ubi_eba_write_leb_st - write data to static volume. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @buf: data to write + * @len: how many bytes to write + * @used_ebs: how many logical eraseblocks will this volume contain + * + * This function writes data to logical eraseblock @lnum of static volume + * @vol. The @used_ebs argument should contain total number of logical + * eraseblock in this static volume. + * + * When writing to the last logical eraseblock, the @len argument doesn't have + * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent + * to the real data size, although the @buf buffer has to contain the + * alignment. In all other cases, @len has to be aligned. + * + * It is prohibited to write more than once to logical eraseblocks of static + * volumes. This function returns zero in case of success and a negative error + * code in case of failure. + */ +int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol, + int lnum, const void *buf, int len, int used_ebs) +{ + int err, pnum, tries = 0, data_size = len, vol_id = vol->vol_id; + struct ubi_vid_hdr *vid_hdr; + uint32_t crc; + + if (ubi->ro_mode) + return -EROFS; + + if (lnum == used_ebs - 1) + /* If this is the last LEB @len may be unaligned */ + len = ALIGN(data_size, ubi->min_io_size); + else + ubi_assert(!(len & (ubi->min_io_size - 1))); + + vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); + if (!vid_hdr) + return -ENOMEM; + + err = leb_write_lock(ubi, vol_id, lnum); + if (err) { + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + vid_hdr->vol_id = cpu_to_be32(vol_id); + vid_hdr->lnum = cpu_to_be32(lnum); + vid_hdr->compat = ubi_get_compat(ubi, vol_id); + vid_hdr->data_pad = cpu_to_be32(vol->data_pad); + + crc = crc32(UBI_CRC32_INIT, buf, data_size); + vid_hdr->vol_type = UBI_VID_STATIC; + vid_hdr->data_size = cpu_to_be32(data_size); + vid_hdr->used_ebs = cpu_to_be32(used_ebs); + vid_hdr->data_crc = cpu_to_be32(crc); + +retry: + pnum = ubi_wl_get_peb(ubi); + if (pnum < 0) { + ubi_free_vid_hdr(ubi, vid_hdr); + leb_write_unlock(ubi, vol_id, lnum); + up_read(&ubi->fm_eba_sem); + return pnum; + } + + dbg_eba("write VID hdr and %d bytes at LEB %d:%d, PEB %d, used_ebs %d", + len, vol_id, lnum, pnum, used_ebs); + + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr); + if (err) { + ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d", + vol_id, lnum, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + err = ubi_io_write_data(ubi, buf, pnum, 0, len); + if (err) { + ubi_warn(ubi, "failed to write %d bytes of data to PEB %d", + len, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + ubi_assert(vol->eba_tbl[lnum] < 0); + vol->eba_tbl[lnum] = pnum; + up_read(&ubi->fm_eba_sem); + + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return 0; + +write_error: + if (err != -EIO || !ubi->bad_allowed) { + /* + * This flash device does not admit of bad eraseblocks or + * something nasty and unexpected happened. Switch to read-only + * mode just in case. + */ + ubi_ro_mode(ubi); + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + + err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1); + if (err || ++tries > UBI_IO_RETRIES) { + ubi_ro_mode(ubi); + leb_write_unlock(ubi, vol_id, lnum); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + } + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + ubi_msg(ubi, "try another PEB"); + goto retry; +} + +/* + * ubi_eba_atomic_leb_change - change logical eraseblock atomically. + * @ubi: UBI device description object + * @vol: volume description object + * @lnum: logical eraseblock number + * @buf: data to write + * @len: how many bytes to write + * + * This function changes the contents of a logical eraseblock atomically. @buf + * has to contain new logical eraseblock data, and @len - the length of the + * data, which has to be aligned. This function guarantees that in case of an + * unclean reboot the old contents is preserved. Returns zero in case of + * success and a negative error code in case of failure. + * + * UBI reserves one LEB for the "atomic LEB change" operation, so only one + * LEB change may be done at a time. This is ensured by @ubi->alc_mutex. + */ +int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol, + int lnum, const void *buf, int len) +{ + int err, pnum, old_pnum, tries = 0, vol_id = vol->vol_id; + struct ubi_vid_hdr *vid_hdr; + uint32_t crc; + + if (ubi->ro_mode) + return -EROFS; + + if (len == 0) { + /* + * Special case when data length is zero. In this case the LEB + * has to be unmapped and mapped somewhere else. + */ + err = ubi_eba_unmap_leb(ubi, vol, lnum); + if (err) + return err; + return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0); + } + + vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS); + if (!vid_hdr) + return -ENOMEM; + + mutex_lock(&ubi->alc_mutex); + err = leb_write_lock(ubi, vol_id, lnum); + if (err) + goto out_mutex; + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + vid_hdr->vol_id = cpu_to_be32(vol_id); + vid_hdr->lnum = cpu_to_be32(lnum); + vid_hdr->compat = ubi_get_compat(ubi, vol_id); + vid_hdr->data_pad = cpu_to_be32(vol->data_pad); + + crc = crc32(UBI_CRC32_INIT, buf, len); + vid_hdr->vol_type = UBI_VID_DYNAMIC; + vid_hdr->data_size = cpu_to_be32(len); + vid_hdr->copy_flag = 1; + vid_hdr->data_crc = cpu_to_be32(crc); + +retry: + pnum = ubi_wl_get_peb(ubi); + if (pnum < 0) { + err = pnum; + up_read(&ubi->fm_eba_sem); + goto out_leb_unlock; + } + + dbg_eba("change LEB %d:%d, PEB %d, write VID hdr to PEB %d", + vol_id, lnum, vol->eba_tbl[lnum], pnum); + + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr); + if (err) { + ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d", + vol_id, lnum, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + err = ubi_io_write_data(ubi, buf, pnum, 0, len); + if (err) { + ubi_warn(ubi, "failed to write %d bytes of data to PEB %d", + len, pnum); + up_read(&ubi->fm_eba_sem); + goto write_error; + } + + old_pnum = vol->eba_tbl[lnum]; + vol->eba_tbl[lnum] = pnum; + up_read(&ubi->fm_eba_sem); + + if (old_pnum >= 0) { + err = ubi_wl_put_peb(ubi, vol_id, lnum, old_pnum, 0); + if (err) + goto out_leb_unlock; + } + +out_leb_unlock: + leb_write_unlock(ubi, vol_id, lnum); +out_mutex: + mutex_unlock(&ubi->alc_mutex); + ubi_free_vid_hdr(ubi, vid_hdr); + return err; + +write_error: + if (err != -EIO || !ubi->bad_allowed) { + /* + * This flash device does not admit of bad eraseblocks or + * something nasty and unexpected happened. Switch to read-only + * mode just in case. + */ + ubi_ro_mode(ubi); + goto out_leb_unlock; + } + + err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1); + if (err || ++tries > UBI_IO_RETRIES) { + ubi_ro_mode(ubi); + goto out_leb_unlock; + } + + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + ubi_msg(ubi, "try another PEB"); + goto retry; +} + +/** + * is_error_sane - check whether a read error is sane. + * @err: code of the error happened during reading + * + * This is a helper function for 'ubi_eba_copy_leb()' which is called when we + * cannot read data from the target PEB (an error @err happened). If the error + * code is sane, then we treat this error as non-fatal. Otherwise the error is + * fatal and UBI will be switched to R/O mode later. + * + * The idea is that we try not to switch to R/O mode if the read error is + * something which suggests there was a real read problem. E.g., %-EIO. Or a + * memory allocation failed (-%ENOMEM). Otherwise, it is safer to switch to R/O + * mode, simply because we do not know what happened at the MTD level, and we + * cannot handle this. E.g., the underlying driver may have become crazy, and + * it is safer to switch to R/O mode to preserve the data. + * + * And bear in mind, this is about reading from the target PEB, i.e. the PEB + * which we have just written. + */ +static int is_error_sane(int err) +{ + if (err == -EIO || err == -ENOMEM || err == UBI_IO_BAD_HDR || + err == UBI_IO_BAD_HDR_EBADMSG || err == -ETIMEDOUT) + return 0; + return 1; +} + +/** + * ubi_eba_copy_leb - copy logical eraseblock. + * @ubi: UBI device description object + * @from: physical eraseblock number from where to copy + * @to: physical eraseblock number where to copy + * @vid_hdr: VID header of the @from physical eraseblock + * + * This function copies logical eraseblock from physical eraseblock @from to + * physical eraseblock @to. The @vid_hdr buffer may be changed by this + * function. Returns: + * o %0 in case of success; + * o %MOVE_CANCEL_RACE, %MOVE_TARGET_WR_ERR, %MOVE_TARGET_BITFLIPS, etc; + * o a negative error code in case of failure. + */ +int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to, + struct ubi_vid_hdr *vid_hdr) +{ + int err, vol_id, lnum, data_size, aldata_size, idx; + struct ubi_volume *vol; + uint32_t crc; + + vol_id = be32_to_cpu(vid_hdr->vol_id); + lnum = be32_to_cpu(vid_hdr->lnum); + + dbg_wl("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to); + + if (vid_hdr->vol_type == UBI_VID_STATIC) { + data_size = be32_to_cpu(vid_hdr->data_size); + aldata_size = ALIGN(data_size, ubi->min_io_size); + } else + data_size = aldata_size = + ubi->leb_size - be32_to_cpu(vid_hdr->data_pad); + + idx = vol_id2idx(ubi, vol_id); + spin_lock(&ubi->volumes_lock); + /* + * Note, we may race with volume deletion, which means that the volume + * this logical eraseblock belongs to might be being deleted. Since the + * volume deletion un-maps all the volume's logical eraseblocks, it will + * be locked in 'ubi_wl_put_peb()' and wait for the WL worker to finish. + */ + vol = ubi->volumes[idx]; + spin_unlock(&ubi->volumes_lock); + if (!vol) { + /* No need to do further work, cancel */ + dbg_wl("volume %d is being removed, cancel", vol_id); + return MOVE_CANCEL_RACE; + } + + /* + * We do not want anybody to write to this logical eraseblock while we + * are moving it, so lock it. + * + * Note, we are using non-waiting locking here, because we cannot sleep + * on the LEB, since it may cause deadlocks. Indeed, imagine a task is + * unmapping the LEB which is mapped to the PEB we are going to move + * (@from). This task locks the LEB and goes sleep in the + * 'ubi_wl_put_peb()' function on the @ubi->move_mutex. In turn, we are + * holding @ubi->move_mutex and go sleep on the LEB lock. So, if the + * LEB is already locked, we just do not move it and return + * %MOVE_RETRY. Note, we do not return %MOVE_CANCEL_RACE here because + * we do not know the reasons of the contention - it may be just a + * normal I/O on this LEB, so we want to re-try. + */ + err = leb_write_trylock(ubi, vol_id, lnum); + if (err) { + dbg_wl("contention on LEB %d:%d, cancel", vol_id, lnum); + return MOVE_RETRY; + } + + /* + * The LEB might have been put meanwhile, and the task which put it is + * probably waiting on @ubi->move_mutex. No need to continue the work, + * cancel it. + */ + if (vol->eba_tbl[lnum] != from) { + dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel", + vol_id, lnum, from, vol->eba_tbl[lnum]); + err = MOVE_CANCEL_RACE; + goto out_unlock_leb; + } + + /* + * OK, now the LEB is locked and we can safely start moving it. Since + * this function utilizes the @ubi->peb_buf buffer which is shared + * with some other functions - we lock the buffer by taking the + * @ubi->buf_mutex. + */ + mutex_lock(&ubi->buf_mutex); + dbg_wl("read %d bytes of data", aldata_size); + err = ubi_io_read_data(ubi, ubi->peb_buf, from, 0, aldata_size); + if (err && err != UBI_IO_BITFLIPS) { + ubi_warn(ubi, "error %d while reading data from PEB %d", + err, from); + err = MOVE_SOURCE_RD_ERR; + goto out_unlock_buf; + } + + /* + * Now we have got to calculate how much data we have to copy. In + * case of a static volume it is fairly easy - the VID header contains + * the data size. In case of a dynamic volume it is more difficult - we + * have to read the contents, cut 0xFF bytes from the end and copy only + * the first part. We must do this to avoid writing 0xFF bytes as it + * may have some side-effects. And not only this. It is important not + * to include those 0xFFs to CRC because later the they may be filled + * by data. + */ + if (vid_hdr->vol_type == UBI_VID_DYNAMIC) + aldata_size = data_size = + ubi_calc_data_len(ubi, ubi->peb_buf, data_size); + + cond_resched(); + crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size); + cond_resched(); + + /* + * It may turn out to be that the whole @from physical eraseblock + * contains only 0xFF bytes. Then we have to only write the VID header + * and do not write any data. This also means we should not set + * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc. + */ + if (data_size > 0) { + vid_hdr->copy_flag = 1; + vid_hdr->data_size = cpu_to_be32(data_size); + vid_hdr->data_crc = cpu_to_be32(crc); + } + vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi)); + + err = ubi_io_write_vid_hdr(ubi, to, vid_hdr); + if (err) { + if (err == -EIO) + err = MOVE_TARGET_WR_ERR; + goto out_unlock_buf; + } + + cond_resched(); + + /* Read the VID header back and check if it was written correctly */ + err = ubi_io_read_vid_hdr(ubi, to, vid_hdr, 1); + if (err) { + if (err != UBI_IO_BITFLIPS) { + ubi_warn(ubi, "error %d while reading VID header back from PEB %d", + err, to); + if (is_error_sane(err)) + err = MOVE_TARGET_RD_ERR; + } else + err = MOVE_TARGET_BITFLIPS; + goto out_unlock_buf; + } + + if (data_size > 0) { + err = ubi_io_write_data(ubi, ubi->peb_buf, to, 0, aldata_size); + if (err) { + if (err == -EIO) + err = MOVE_TARGET_WR_ERR; + goto out_unlock_buf; + } + + cond_resched(); + + /* + * We've written the data and are going to read it back to make + * sure it was written correctly. + */ + memset(ubi->peb_buf, 0xFF, aldata_size); + err = ubi_io_read_data(ubi, ubi->peb_buf, to, 0, aldata_size); + if (err) { + if (err != UBI_IO_BITFLIPS) { + ubi_warn(ubi, "error %d while reading data back from PEB %d", + err, to); + if (is_error_sane(err)) + err = MOVE_TARGET_RD_ERR; + } else + err = MOVE_TARGET_BITFLIPS; + goto out_unlock_buf; + } + + cond_resched(); + + if (crc != crc32(UBI_CRC32_INIT, ubi->peb_buf, data_size)) { + ubi_warn(ubi, "read data back from PEB %d and it is different", + to); + err = -EINVAL; + goto out_unlock_buf; + } + } + + ubi_assert(vol->eba_tbl[lnum] == from); + down_read(&ubi->fm_eba_sem); + vol->eba_tbl[lnum] = to; + up_read(&ubi->fm_eba_sem); + +out_unlock_buf: + mutex_unlock(&ubi->buf_mutex); +out_unlock_leb: + leb_write_unlock(ubi, vol_id, lnum); + return err; +} + +/** + * print_rsvd_warning - warn about not having enough reserved PEBs. + * @ubi: UBI device description object + * + * This is a helper function for 'ubi_eba_init()' which is called when UBI + * cannot reserve enough PEBs for bad block handling. This function makes a + * decision whether we have to print a warning or not. The algorithm is as + * follows: + * o if this is a new UBI image, then just print the warning + * o if this is an UBI image which has already been used for some time, print + * a warning only if we can reserve less than 10% of the expected amount of + * the reserved PEB. + * + * The idea is that when UBI is used, PEBs become bad, and the reserved pool + * of PEBs becomes smaller, which is normal and we do not want to scare users + * with a warning every time they attach the MTD device. This was an issue + * reported by real users. + */ +static void print_rsvd_warning(struct ubi_device *ubi, + struct ubi_attach_info *ai) +{ + /* + * The 1 << 18 (256KiB) number is picked randomly, just a reasonably + * large number to distinguish between newly flashed and used images. + */ + if (ai->max_sqnum > (1 << 18)) { + int min = ubi->beb_rsvd_level / 10; + + if (!min) + min = 1; + if (ubi->beb_rsvd_pebs > min) + return; + } + + ubi_warn(ubi, "cannot reserve enough PEBs for bad PEB handling, reserved %d, need %d", + ubi->beb_rsvd_pebs, ubi->beb_rsvd_level); + if (ubi->corr_peb_count) + ubi_warn(ubi, "%d PEBs are corrupted and not used", + ubi->corr_peb_count); +} + +/** + * self_check_eba - run a self check on the EBA table constructed by fastmap. + * @ubi: UBI device description object + * @ai_fastmap: UBI attach info object created by fastmap + * @ai_scan: UBI attach info object created by scanning + * + * Returns < 0 in case of an internal error, 0 otherwise. + * If a bad EBA table entry was found it will be printed out and + * ubi_assert() triggers. + */ +int self_check_eba(struct ubi_device *ubi, struct ubi_attach_info *ai_fastmap, + struct ubi_attach_info *ai_scan) +{ + int i, j, num_volumes, ret = 0; + int **scan_eba, **fm_eba; + struct ubi_ainf_volume *av; + struct ubi_volume *vol; + struct ubi_ainf_peb *aeb; + struct rb_node *rb; + + num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT; + + scan_eba = kmalloc(sizeof(*scan_eba) * num_volumes, GFP_KERNEL); + if (!scan_eba) + return -ENOMEM; + + fm_eba = kmalloc(sizeof(*fm_eba) * num_volumes, GFP_KERNEL); + if (!fm_eba) { + kfree(scan_eba); + return -ENOMEM; + } + + for (i = 0; i < num_volumes; i++) { + vol = ubi->volumes[i]; + if (!vol) + continue; + + scan_eba[i] = kmalloc(vol->reserved_pebs * sizeof(**scan_eba), + GFP_KERNEL); + if (!scan_eba[i]) { + ret = -ENOMEM; + goto out_free; + } + + fm_eba[i] = kmalloc(vol->reserved_pebs * sizeof(**fm_eba), + GFP_KERNEL); + if (!fm_eba[i]) { + ret = -ENOMEM; + goto out_free; + } + + for (j = 0; j < vol->reserved_pebs; j++) + scan_eba[i][j] = fm_eba[i][j] = UBI_LEB_UNMAPPED; + + av = ubi_find_av(ai_scan, idx2vol_id(ubi, i)); + if (!av) + continue; + + ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) + scan_eba[i][aeb->lnum] = aeb->pnum; + + av = ubi_find_av(ai_fastmap, idx2vol_id(ubi, i)); + if (!av) + continue; + + ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) + fm_eba[i][aeb->lnum] = aeb->pnum; + + for (j = 0; j < vol->reserved_pebs; j++) { + if (scan_eba[i][j] != fm_eba[i][j]) { + if (scan_eba[i][j] == UBI_LEB_UNMAPPED || + fm_eba[i][j] == UBI_LEB_UNMAPPED) + continue; + + ubi_err(ubi, "LEB:%i:%i is PEB:%i instead of %i!", + vol->vol_id, i, fm_eba[i][j], + scan_eba[i][j]); + ubi_assert(0); + } + } + } + +out_free: + for (i = 0; i < num_volumes; i++) { + if (!ubi->volumes[i]) + continue; + + kfree(scan_eba[i]); + kfree(fm_eba[i]); + } + + kfree(scan_eba); + kfree(fm_eba); + return ret; +} + +/** + * ubi_eba_init - initialize the EBA sub-system using attaching information. + * @ubi: UBI device description object + * @ai: attaching information + * + * This function returns zero in case of success and a negative error code in + * case of failure. + */ +int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai) +{ + int i, j, err, num_volumes; + struct ubi_ainf_volume *av; + struct ubi_volume *vol; + struct ubi_ainf_peb *aeb; + struct rb_node *rb; + + dbg_eba("initialize EBA sub-system"); + + spin_lock_init(&ubi->ltree_lock); + mutex_init(&ubi->alc_mutex); + ubi->ltree = RB_ROOT; + + ubi->global_sqnum = ai->max_sqnum + 1; + num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT; + + for (i = 0; i < num_volumes; i++) { + vol = ubi->volumes[i]; + if (!vol) + continue; + + cond_resched(); + + vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int), + GFP_KERNEL); + if (!vol->eba_tbl) { + err = -ENOMEM; + goto out_free; + } + + for (j = 0; j < vol->reserved_pebs; j++) + vol->eba_tbl[j] = UBI_LEB_UNMAPPED; + + av = ubi_find_av(ai, idx2vol_id(ubi, i)); + if (!av) + continue; + + ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) { + if (aeb->lnum >= vol->reserved_pebs) + /* + * This may happen in case of an unclean reboot + * during re-size. + */ + ubi_move_aeb_to_list(av, aeb, &ai->erase); + else + vol->eba_tbl[aeb->lnum] = aeb->pnum; + } + } + + if (ubi->avail_pebs < EBA_RESERVED_PEBS) { + ubi_err(ubi, "no enough physical eraseblocks (%d, need %d)", + ubi->avail_pebs, EBA_RESERVED_PEBS); + if (ubi->corr_peb_count) + ubi_err(ubi, "%d PEBs are corrupted and not used", + ubi->corr_peb_count); + err = -ENOSPC; + goto out_free; + } + ubi->avail_pebs -= EBA_RESERVED_PEBS; + ubi->rsvd_pebs += EBA_RESERVED_PEBS; + + if (ubi->bad_allowed) { + ubi_calculate_reserved(ubi); + + if (ubi->avail_pebs < ubi->beb_rsvd_level) { + /* No enough free physical eraseblocks */ + ubi->beb_rsvd_pebs = ubi->avail_pebs; + print_rsvd_warning(ubi, ai); + } else + ubi->beb_rsvd_pebs = ubi->beb_rsvd_level; + + ubi->avail_pebs -= ubi->beb_rsvd_pebs; + ubi->rsvd_pebs += ubi->beb_rsvd_pebs; + } + + dbg_eba("EBA sub-system is initialized"); + return 0; + +out_free: + for (i = 0; i < num_volumes; i++) { + if (!ubi->volumes[i]) + continue; + kfree(ubi->volumes[i]->eba_tbl); + ubi->volumes[i]->eba_tbl = NULL; + } + return err; +} |