OSCL-LXR linux-6.0.1/​drivers/​mtd/​ubi/​vtbl.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) International Business Machines Corp., 2006
  * Copyright (c) Nokia Corporation, 2006, 2007
  *
  * Author: Artem Bityutskiy (Битюцкий Артём)
  */
 
 /*
  * This file includes volume table manipulation code. The volume table is an
  * on-flash table containing volume meta-data like name, number of reserved
  * physical eraseblocks, type, etc. The volume table is stored in the so-called
  * "layout volume".
  *
  * The layout volume is an internal volume which is organized as follows. It
  * consists of two logical eraseblocks - LEB 0 and LEB 1. Each logical
  * eraseblock stores one volume table copy, i.e. LEB 0 and LEB 1 duplicate each
  * other. This redundancy guarantees robustness to unclean reboots. The volume
  * table is basically an array of volume table records. Each record contains
  * full information about the volume and protected by a CRC checksum. Note,
  * nowadays we use the atomic LEB change operation when updating the volume
  * table, so we do not really need 2 LEBs anymore, but we preserve the older
  * design for the backward compatibility reasons.
  *
  * When the volume table is changed, it is first changed in RAM. Then LEB 0 is
  * erased, and the updated volume table is written back to LEB 0. Then same for
  * LEB 1. This scheme guarantees recoverability from unclean reboots.
  *
  * In this UBI implementation the on-flash volume table does not contain any
  * information about how much data static volumes contain.
  *
  * But it would still be beneficial to store this information in the volume
  * table. For example, suppose we have a static volume X, and all its physical
  * eraseblocks became bad for some reasons. Suppose we are attaching the
  * corresponding MTD device, for some reason we find no logical eraseblocks
  * corresponding to the volume X. According to the volume table volume X does
  * exist. So we don't know whether it is just empty or all its physical
  * eraseblocks went bad. So we cannot alarm the user properly.
  *
  * The volume table also stores so-called "update marker", which is used for
  * volume updates. Before updating the volume, the update marker is set, and
  * after the update operation is finished, the update marker is cleared. So if
  * the update operation was interrupted (e.g. by an unclean reboot) - the
  * update marker is still there and we know that the volume's contents is
  * damaged.
  */
 
 #include <linux/crc32.h>
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <asm/div64.h>
 #include "ubi.h"
 
 static void self_vtbl_check(const struct ubi_device *ubi);
 
 /* Empty volume table record */
 static struct ubi_vtbl_record empty_vtbl_record;
 
 /**
  * ubi_update_layout_vol - helper for updatting layout volumes on flash
  * @ubi: UBI device description object
  */
 static int ubi_update_layout_vol(struct ubi_device *ubi)
 {
     struct ubi_volume *layout_vol;
     int i, err;
 
     layout_vol = ubi->volumes[vol_id2idx(ubi, UBI_LAYOUT_VOLUME_ID)];
     for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
         err = ubi_eba_atomic_leb_change(ubi, layout_vol, i, ubi->vtbl,
                         ubi->vtbl_size);
         if (err)
             return err;
     }
 
     return 0;
 }
 
 /**
  * ubi_change_vtbl_record - change volume table record.
  * @ubi: UBI device description object
  * @idx: table index to change
  * @vtbl_rec: new volume table record
  *
  * This function changes volume table record @idx. If @vtbl_rec is %NULL, empty
  * volume table record is written. The caller does not have to calculate CRC of
  * the record as it is done by this function. Returns zero in case of success
  * and a negative error code in case of failure.
  */
 int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
                struct ubi_vtbl_record *vtbl_rec)
 {
     int err;
     uint32_t crc;
 
     ubi_assert(idx >= 0 && idx < ubi->vtbl_slots);
 
     if (!vtbl_rec)
         vtbl_rec = &empty_vtbl_record;
     else {
         crc = crc32(UBI_CRC32_INIT, vtbl_rec, UBI_VTBL_RECORD_SIZE_CRC);
         vtbl_rec->crc = cpu_to_be32(crc);
     }
 
     memcpy(&ubi->vtbl[idx], vtbl_rec, sizeof(struct ubi_vtbl_record));
     err = ubi_update_layout_vol(ubi);
 
     self_vtbl_check(ubi);
     return err ? err : 0;
 }
 
 /**
  * ubi_vtbl_rename_volumes - rename UBI volumes in the volume table.
  * @ubi: UBI device description object
  * @rename_list: list of &struct ubi_rename_entry objects
  *
  * This function re-names multiple volumes specified in @req in the volume
  * table. Returns zero in case of success and a negative error code in case of
  * failure.
  */
 int ubi_vtbl_rename_volumes(struct ubi_device *ubi,
                 struct list_head *rename_list)
 {
     struct ubi_rename_entry *re;
 
     list_for_each_entry(re, rename_list, list) {
         uint32_t crc;
         struct ubi_volume *vol = re->desc->vol;
         struct ubi_vtbl_record *vtbl_rec = &ubi->vtbl[vol->vol_id];
 
         if (re->remove) {
             memcpy(vtbl_rec, &empty_vtbl_record,
                    sizeof(struct ubi_vtbl_record));
             continue;
         }
 
         vtbl_rec->name_len = cpu_to_be16(re->new_name_len);
         memcpy(vtbl_rec->name, re->new_name, re->new_name_len);
         memset(vtbl_rec->name + re->new_name_len, 0,
                UBI_VOL_NAME_MAX + 1 - re->new_name_len);
         crc = crc32(UBI_CRC32_INIT, vtbl_rec,
                 UBI_VTBL_RECORD_SIZE_CRC);
         vtbl_rec->crc = cpu_to_be32(crc);
     }
 
     return ubi_update_layout_vol(ubi);
 }
 
 /**
  * vtbl_check - check if volume table is not corrupted and sensible.
  * @ubi: UBI device description object
  * @vtbl: volume table
  *
  * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
  * and %-EINVAL if it contains inconsistent data.
  */
 static int vtbl_check(const struct ubi_device *ubi,
               const struct ubi_vtbl_record *vtbl)
 {
     int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
     int upd_marker, err;
     uint32_t crc;
     const char *name;
 
     for (i = 0; i < ubi->vtbl_slots; i++) {
         cond_resched();
 
         reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
         alignment = be32_to_cpu(vtbl[i].alignment);
         data_pad = be32_to_cpu(vtbl[i].data_pad);
         upd_marker = vtbl[i].upd_marker;
         vol_type = vtbl[i].vol_type;
         name_len = be16_to_cpu(vtbl[i].name_len);
         name = &vtbl[i].name[0];
 
         crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
         if (be32_to_cpu(vtbl[i].crc) != crc) {
             ubi_err(ubi, "bad CRC at record %u: %#08x, not %#08x",
                  i, crc, be32_to_cpu(vtbl[i].crc));
             ubi_dump_vtbl_record(&vtbl[i], i);
             return 1;
         }
 
         if (reserved_pebs == 0) {
             if (memcmp(&vtbl[i], &empty_vtbl_record,
                         UBI_VTBL_RECORD_SIZE)) {
                 err = 2;
                 goto bad;
             }
             continue;
         }
 
         if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
             name_len < 0) {
             err = 3;
             goto bad;
         }
 
         if (alignment > ubi->leb_size || alignment == 0) {
             err = 4;
             goto bad;
         }
 
         n = alignment & (ubi->min_io_size - 1);
         if (alignment != 1 && n) {
             err = 5;
             goto bad;
         }
 
         n = ubi->leb_size % alignment;
         if (data_pad != n) {
             ubi_err(ubi, "bad data_pad, has to be %d", n);
             err = 6;
             goto bad;
         }
 
         if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
             err = 7;
             goto bad;
         }
 
         if (upd_marker != 0 && upd_marker != 1) {
             err = 8;
             goto bad;
         }
 
         if (reserved_pebs > ubi->good_peb_count) {
             ubi_err(ubi, "too large reserved_pebs %d, good PEBs %d",
                 reserved_pebs, ubi->good_peb_count);
             err = 9;
             goto bad;
         }
 
         if (name_len > UBI_VOL_NAME_MAX) {
             err = 10;
             goto bad;
         }
 
         if (name[0] == '\0') {
             err = 11;
             goto bad;
         }
 
         if (name_len != strnlen(name, name_len + 1)) {
             err = 12;
             goto bad;
         }
     }
 
     /* Checks that all names are unique */
     for (i = 0; i < ubi->vtbl_slots - 1; i++) {
         for (n = i + 1; n < ubi->vtbl_slots; n++) {
             int len1 = be16_to_cpu(vtbl[i].name_len);
             int len2 = be16_to_cpu(vtbl[n].name_len);
 
             if (len1 > 0 && len1 == len2 &&
                 !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
                 ubi_err(ubi, "volumes %d and %d have the same name \"%s\"",
                     i, n, vtbl[i].name);
                 ubi_dump_vtbl_record(&vtbl[i], i);
                 ubi_dump_vtbl_record(&vtbl[n], n);
                 return -EINVAL;
             }
         }
     }
 
     return 0;
 
 bad:
     ubi_err(ubi, "volume table check failed: record %d, error %d", i, err);
     ubi_dump_vtbl_record(&vtbl[i], i);
     return -EINVAL;
 }
 
 /**
  * create_vtbl - create a copy of volume table.
  * @ubi: UBI device description object
  * @ai: attaching information
  * @copy: number of the volume table copy
  * @vtbl: contents of the volume table
  *
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
 static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai,
                int copy, void *vtbl)
 {
     int err, tries = 0;
     struct ubi_vid_io_buf *vidb;
     struct ubi_vid_hdr *vid_hdr;
     struct ubi_ainf_peb *new_aeb;
 
     dbg_gen("create volume table (copy #%d)", copy + 1);
 
     vidb = ubi_alloc_vid_buf(ubi, GFP_KERNEL);
     if (!vidb)
         return -ENOMEM;
 
     vid_hdr = ubi_get_vid_hdr(vidb);
 
 retry:
     new_aeb = ubi_early_get_peb(ubi, ai);
     if (IS_ERR(new_aeb)) {
         err = PTR_ERR(new_aeb);
         goto out_free;
     }
 
     vid_hdr->vol_type = UBI_LAYOUT_VOLUME_TYPE;
     vid_hdr->vol_id = cpu_to_be32(UBI_LAYOUT_VOLUME_ID);
     vid_hdr->compat = UBI_LAYOUT_VOLUME_COMPAT;
     vid_hdr->data_size = vid_hdr->used_ebs =
                  vid_hdr->data_pad = cpu_to_be32(0);
     vid_hdr->lnum = cpu_to_be32(copy);
     vid_hdr->sqnum = cpu_to_be64(++ai->max_sqnum);
 
     /* The EC header is already there, write the VID header */
     err = ubi_io_write_vid_hdr(ubi, new_aeb->pnum, vidb);
     if (err)
         goto write_error;
 
     /* Write the layout volume contents */
     err = ubi_io_write_data(ubi, vtbl, new_aeb->pnum, 0, ubi->vtbl_size);
     if (err)
         goto write_error;
 
     /*
      * And add it to the attaching information. Don't delete the old version
      * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'.
      */
     err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0);
     ubi_free_aeb(ai, new_aeb);
     ubi_free_vid_buf(vidb);
     return err;
 
 write_error:
     if (err == -EIO && ++tries <= 5) {
         /*
          * Probably this physical eraseblock went bad, try to pick
          * another one.
          */
         list_add(&new_aeb->u.list, &ai->erase);
         goto retry;
     }
     ubi_free_aeb(ai, new_aeb);
 out_free:
     ubi_free_vid_buf(vidb);
     return err;
 
 }
 
 /**
  * process_lvol - process the layout volume.
  * @ubi: UBI device description object
  * @ai: attaching information
  * @av: layout volume attaching information
  *
  * This function is responsible for reading the layout volume, ensuring it is
  * not corrupted, and recovering from corruptions if needed. Returns volume
  * table in case of success and a negative error code in case of failure.
  */
 static struct ubi_vtbl_record *process_lvol(struct ubi_device *ubi,
                         struct ubi_attach_info *ai,
                         struct ubi_ainf_volume *av)
 {
     int err;
     struct rb_node *rb;
     struct ubi_ainf_peb *aeb;
     struct ubi_vtbl_record *leb[UBI_LAYOUT_VOLUME_EBS] = { NULL, NULL };
     int leb_corrupted[UBI_LAYOUT_VOLUME_EBS] = {1, 1};
 
     /*
      * UBI goes through the following steps when it changes the layout
      * volume:
      * a. erase LEB 0;
      * b. write new data to LEB 0;
      * c. erase LEB 1;
      * d. write new data to LEB 1.
      *
      * Before the change, both LEBs contain the same data.
      *
      * Due to unclean reboots, the contents of LEB 0 may be lost, but there
      * should LEB 1. So it is OK if LEB 0 is corrupted while LEB 1 is not.
      * Similarly, LEB 1 may be lost, but there should be LEB 0. And
      * finally, unclean reboots may result in a situation when neither LEB
      * 0 nor LEB 1 are corrupted, but they are different. In this case, LEB
      * 0 contains more recent information.
      *
      * So the plan is to first check LEB 0. Then
      * a. if LEB 0 is OK, it must be containing the most recent data; then
      *    we compare it with LEB 1, and if they are different, we copy LEB
      *    0 to LEB 1;
      * b. if LEB 0 is corrupted, but LEB 1 has to be OK, and we copy LEB 1
      *    to LEB 0.
      */
 
     dbg_gen("check layout volume");
 
     /* Read both LEB 0 and LEB 1 into memory */
     ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
         leb[aeb->lnum] = vzalloc(ubi->vtbl_size);
         if (!leb[aeb->lnum]) {
             err = -ENOMEM;
             goto out_free;
         }
 
         err = ubi_io_read_data(ubi, leb[aeb->lnum], aeb->pnum, 0,
                        ubi->vtbl_size);
         if (err == UBI_IO_BITFLIPS || mtd_is_eccerr(err))
             /*
              * Scrub the PEB later. Note, -EBADMSG indicates an
              * uncorrectable ECC error, but we have our own CRC and
              * the data will be checked later. If the data is OK,
              * the PEB will be scrubbed (because we set
              * aeb->scrub). If the data is not OK, the contents of
              * the PEB will be recovered from the second copy, and
              * aeb->scrub will be cleared in
              * 'ubi_add_to_av()'.
              */
             aeb->scrub = 1;
         else if (err)
             goto out_free;
     }
 
     err = -EINVAL;
     if (leb[0]) {
         leb_corrupted[0] = vtbl_check(ubi, leb[0]);
         if (leb_corrupted[0] < 0)
             goto out_free;
     }
 
     if (!leb_corrupted[0]) {
         /* LEB 0 is OK */
         if (leb[1])
             leb_corrupted[1] = memcmp(leb[0], leb[1],
                           ubi->vtbl_size);
         if (leb_corrupted[1]) {
             ubi_warn(ubi, "volume table copy #2 is corrupted");
             err = create_vtbl(ubi, ai, 1, leb[0]);
             if (err)
                 goto out_free;
             ubi_msg(ubi, "volume table was restored");
         }
 
         /* Both LEB 1 and LEB 2 are OK and consistent */
         vfree(leb[1]);
         return leb[0];
     } else {
         /* LEB 0 is corrupted or does not exist */
         if (leb[1]) {
             leb_corrupted[1] = vtbl_check(ubi, leb[1]);
             if (leb_corrupted[1] < 0)
                 goto out_free;
         }
         if (leb_corrupted[1]) {
             /* Both LEB 0 and LEB 1 are corrupted */
             ubi_err(ubi, "both volume tables are corrupted");
             goto out_free;
         }
 
         ubi_warn(ubi, "volume table copy #1 is corrupted");
         err = create_vtbl(ubi, ai, 0, leb[1]);
         if (err)
             goto out_free;
         ubi_msg(ubi, "volume table was restored");
 
         vfree(leb[0]);
         return leb[1];
     }
 
 out_free:
     vfree(leb[0]);
     vfree(leb[1]);
     return ERR_PTR(err);
 }
 
 /**
  * create_empty_lvol - create empty layout volume.
  * @ubi: UBI device description object
  * @ai: attaching information
  *
  * This function returns volume table contents in case of success and a
  * negative error code in case of failure.
  */
 static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
                          struct ubi_attach_info *ai)
 {
     int i;
     struct ubi_vtbl_record *vtbl;
 
     vtbl = vzalloc(ubi->vtbl_size);
     if (!vtbl)
         return ERR_PTR(-ENOMEM);
 
     for (i = 0; i < ubi->vtbl_slots; i++)
         memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);
 
     for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
         int err;
 
         err = create_vtbl(ubi, ai, i, vtbl);
         if (err) {
             vfree(vtbl);
             return ERR_PTR(err);
         }
     }
 
     return vtbl;
 }
 
 /**
  * init_volumes - initialize volume information for existing volumes.
  * @ubi: UBI device description object
  * @ai: scanning information
  * @vtbl: volume table
  *
  * This function allocates volume description objects for existing volumes.
  * Returns zero in case of success and a negative error code in case of
  * failure.
  */
 static int init_volumes(struct ubi_device *ubi,
             const struct ubi_attach_info *ai,
             const struct ubi_vtbl_record *vtbl)
 {
     int i, err, reserved_pebs = 0;
     struct ubi_ainf_volume *av;
     struct ubi_volume *vol;
 
     for (i = 0; i < ubi->vtbl_slots; i++) {
         cond_resched();
 
         if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
             continue; /* Empty record */
 
         vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
         if (!vol)
             return -ENOMEM;
 
         vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
         vol->alignment = be32_to_cpu(vtbl[i].alignment);
         vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
         vol->upd_marker = vtbl[i].upd_marker;
         vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
                     UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
         vol->name_len = be16_to_cpu(vtbl[i].name_len);
         vol->usable_leb_size = ubi->leb_size - vol->data_pad;
         memcpy(vol->name, vtbl[i].name, vol->name_len);
         vol->name[vol->name_len] = '\0';
         vol->vol_id = i;
 
         if (vtbl[i].flags & UBI_VTBL_SKIP_CRC_CHECK_FLG)
             vol->skip_check = 1;
 
         if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
             /* Auto re-size flag may be set only for one volume */
             if (ubi->autoresize_vol_id != -1) {
                 ubi_err(ubi, "more than one auto-resize volume (%d and %d)",
                     ubi->autoresize_vol_id, i);
                 kfree(vol);
                 return -EINVAL;
             }
 
             ubi->autoresize_vol_id = i;
         }
 
         ubi_assert(!ubi->volumes[i]);
         ubi->volumes[i] = vol;
         ubi->vol_count += 1;
         vol->ubi = ubi;
         reserved_pebs += vol->reserved_pebs;
 
         /*
          * We use ubi->peb_count and not vol->reserved_pebs because
          * we want to keep the code simple. Otherwise we'd have to
          * resize/check the bitmap upon volume resize too.
          * Allocating a few bytes more does not hurt.
          */
         err = ubi_fastmap_init_checkmap(vol, ubi->peb_count);
         if (err)
             return err;
 
         /*
          * In case of dynamic volume UBI knows nothing about how many
          * data is stored there. So assume the whole volume is used.
          */
         if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
             vol->used_ebs = vol->reserved_pebs;
             vol->last_eb_bytes = vol->usable_leb_size;
             vol->used_bytes =
                 (long long)vol->used_ebs * vol->usable_leb_size;
             continue;
         }
 
         /* Static volumes only */
         av = ubi_find_av(ai, i);
         if (!av || !av->leb_count) {
             /*
              * No eraseblocks belonging to this volume found. We
              * don't actually know whether this static volume is
              * completely corrupted or just contains no data. And
              * we cannot know this as long as data size is not
              * stored on flash. So we just assume the volume is
              * empty. FIXME: this should be handled.
              */
             continue;
         }
 
         if (av->leb_count != av->used_ebs) {
             /*
              * We found a static volume which misses several
              * eraseblocks. Treat it as corrupted.
              */
             ubi_warn(ubi, "static volume %d misses %d LEBs - corrupted",
                  av->vol_id, av->used_ebs - av->leb_count);
             vol->corrupted = 1;
             continue;
         }
 
         vol->used_ebs = av->used_ebs;
         vol->used_bytes =
             (long long)(vol->used_ebs - 1) * vol->usable_leb_size;
         vol->used_bytes += av->last_data_size;
         vol->last_eb_bytes = av->last_data_size;
     }
 
     /* And add the layout volume */
     vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
     if (!vol)
         return -ENOMEM;
 
     vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
     vol->alignment = UBI_LAYOUT_VOLUME_ALIGN;
     vol->vol_type = UBI_DYNAMIC_VOLUME;
     vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
     memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
     vol->usable_leb_size = ubi->leb_size;
     vol->used_ebs = vol->reserved_pebs;
     vol->last_eb_bytes = vol->reserved_pebs;
     vol->used_bytes =
         (long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
     vol->vol_id = UBI_LAYOUT_VOLUME_ID;
     vol->ref_count = 1;
 
     ubi_assert(!ubi->volumes[i]);
     ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
     reserved_pebs += vol->reserved_pebs;
     ubi->vol_count += 1;
     vol->ubi = ubi;
     err = ubi_fastmap_init_checkmap(vol, UBI_LAYOUT_VOLUME_EBS);
     if (err)
         return err;
 
     if (reserved_pebs > ubi->avail_pebs) {
         ubi_err(ubi, "not enough PEBs, required %d, available %d",
             reserved_pebs, ubi->avail_pebs);
         if (ubi->corr_peb_count)
             ubi_err(ubi, "%d PEBs are corrupted and not used",
                 ubi->corr_peb_count);
         return -ENOSPC;
     }
     ubi->rsvd_pebs += reserved_pebs;
     ubi->avail_pebs -= reserved_pebs;
 
     return 0;
 }
 
 /**
  * check_av - check volume attaching information.
  * @vol: UBI volume description object
  * @av: volume attaching information
  *
  * This function returns zero if the volume attaching information is consistent
  * to the data read from the volume tabla, and %-EINVAL if not.
  */
 static int check_av(const struct ubi_volume *vol,
             const struct ubi_ainf_volume *av)
 {
     int err;
 
     if (av->highest_lnum >= vol->reserved_pebs) {
         err = 1;
         goto bad;
     }
     if (av->leb_count > vol->reserved_pebs) {
         err = 2;
         goto bad;
     }
     if (av->vol_type != vol->vol_type) {
         err = 3;
         goto bad;
     }
     if (av->used_ebs > vol->reserved_pebs) {
         err = 4;
         goto bad;
     }
     if (av->data_pad != vol->data_pad) {
         err = 5;
         goto bad;
     }
     return 0;
 
 bad:
     ubi_err(vol->ubi, "bad attaching information, error %d", err);
     ubi_dump_av(av);
     ubi_dump_vol_info(vol);
     return -EINVAL;
 }
 
 /**
  * check_attaching_info - check that attaching information.
  * @ubi: UBI device description object
  * @ai: attaching information
  *
  * Even though we protect on-flash data by CRC checksums, we still don't trust
  * the media. This function ensures that attaching information is consistent to
  * the information read from the volume table. Returns zero if the attaching
  * information is OK and %-EINVAL if it is not.
  */
 static int check_attaching_info(const struct ubi_device *ubi,
                    struct ubi_attach_info *ai)
 {
     int err, i;
     struct ubi_ainf_volume *av;
     struct ubi_volume *vol;
 
     if (ai->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
         ubi_err(ubi, "found %d volumes while attaching, maximum is %d + %d",
             ai->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
         return -EINVAL;
     }
 
     if (ai->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
         ai->highest_vol_id < UBI_INTERNAL_VOL_START) {
         ubi_err(ubi, "too large volume ID %d found",
             ai->highest_vol_id);
         return -EINVAL;
     }
 
     for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
         cond_resched();
 
         av = ubi_find_av(ai, i);
         vol = ubi->volumes[i];
         if (!vol) {
             if (av)
                 ubi_remove_av(ai, av);
             continue;
         }
 
         if (vol->reserved_pebs == 0) {
             ubi_assert(i < ubi->vtbl_slots);
 
             if (!av)
                 continue;
 
             /*
              * During attaching we found a volume which does not
              * exist according to the information in the volume
              * table. This must have happened due to an unclean
              * reboot while the volume was being removed. Discard
              * these eraseblocks.
              */
             ubi_msg(ubi, "finish volume %d removal", av->vol_id);
             ubi_remove_av(ai, av);
         } else if (av) {
             err = check_av(vol, av);
             if (err)
                 return err;
         }
     }
 
     return 0;
 }
 
 /**
  * ubi_read_volume_table - read the volume table.
  * @ubi: UBI device description object
  * @ai: attaching information
  *
  * This function reads volume table, checks it, recover from errors if needed,
  * or creates it if needed. Returns zero in case of success and a negative
  * error code in case of failure.
  */
 int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_attach_info *ai)
 {
     int err;
     struct ubi_ainf_volume *av;
 
     empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
 
     /*
      * The number of supported volumes is limited by the eraseblock size
      * and by the UBI_MAX_VOLUMES constant.
      */
     ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
     if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
         ubi->vtbl_slots = UBI_MAX_VOLUMES;
 
     ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
     ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);
 
     av = ubi_find_av(ai, UBI_LAYOUT_VOLUME_ID);
     if (!av) {
         /*
          * No logical eraseblocks belonging to the layout volume were
          * found. This could mean that the flash is just empty. In
          * this case we create empty layout volume.
          *
          * But if flash is not empty this must be a corruption or the
          * MTD device just contains garbage.
          */
         if (ai->is_empty) {
             ubi->vtbl = create_empty_lvol(ubi, ai);
             if (IS_ERR(ubi->vtbl))
                 return PTR_ERR(ubi->vtbl);
         } else {
             ubi_err(ubi, "the layout volume was not found");
             return -EINVAL;
         }
     } else {
         if (av->leb_count > UBI_LAYOUT_VOLUME_EBS) {
             /* This must not happen with proper UBI images */
             ubi_err(ubi, "too many LEBs (%d) in layout volume",
                 av->leb_count);
             return -EINVAL;
         }
 
         ubi->vtbl = process_lvol(ubi, ai, av);
         if (IS_ERR(ubi->vtbl))
             return PTR_ERR(ubi->vtbl);
     }
 
     ubi->avail_pebs = ubi->good_peb_count - ubi->corr_peb_count;
 
     /*
      * The layout volume is OK, initialize the corresponding in-RAM data
      * structures.
      */
     err = init_volumes(ubi, ai, ubi->vtbl);
     if (err)
         goto out_free;
 
     /*
      * Make sure that the attaching information is consistent to the
      * information stored in the volume table.
      */
     err = check_attaching_info(ubi, ai);
     if (err)
         goto out_free;
 
     return 0;
 
 out_free:
     vfree(ubi->vtbl);
     ubi_free_all_volumes(ubi);
     return err;
 }
 
 /**
  * self_vtbl_check - check volume table.
  * @ubi: UBI device description object
  */
 static void self_vtbl_check(const struct ubi_device *ubi)
 {
     if (!ubi_dbg_chk_gen(ubi))
         return;
 
     if (vtbl_check(ubi, ubi->vtbl)) {
         ubi_err(ubi, "self-check failed");
         BUG();
     }
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team