/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include <linux/crc32.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include "nodelist.h"

static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset);
static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);
static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);

static void jffs2_erase_block(struct jffs2_sb_info *c,
                              struct jffs2_eraseblock *jeb)
{
        int ret;
        uint32_t bad_offset;
#ifdef __ECOS
       ret = jffs2_flash_erase(c, jeb);
       if (!ret) {
               jffs2_erase_succeeded(c, jeb);
               return;
       }
       bad_offset = jeb->offset;
#else /* Linux */
        struct erase_info *instr;

        jffs2_dbg(1, "%s(): erase block %#08x (range %#08x-%#08x)\n",
                  __func__,
                  jeb->offset, jeb->offset, jeb->offset + c->sector_size);
        instr = kmalloc(sizeof(struct erase_info), GFP_KERNEL);
        if (!instr) {
                pr_warn("kmalloc for struct erase_info in jffs2_erase_block failed. Refiling block for later\n");
                mutex_lock(&c->erase_free_sem);
                spin_lock(&c->erase_completion_lock);
                list_move(&jeb->list, &c->erase_pending_list);
                c->erasing_size -= c->sector_size;
                c->dirty_size += c->sector_size;
                jeb->dirty_size = c->sector_size;
                spin_unlock(&c->erase_completion_lock);
                mutex_unlock(&c->erase_free_sem);
                return;
        }

        memset(instr, 0, sizeof(*instr));

        instr->addr = jeb->offset;
        instr->len = c->sector_size;

        ret = mtd_erase(c->mtd, instr);
        if (!ret) {
                jffs2_erase_succeeded(c, jeb);
                kfree(instr);
                return;
        }

        bad_offset = instr->fail_addr;
        kfree(instr);
#endif /* __ECOS */

        if (ret == -ENOMEM || ret == -EAGAIN) {
                /* Erase failed immediately. Refile it on the list */
                jffs2_dbg(1, "Erase at 0x%08x failed: %d. Refiling on erase_pending_list\n",
                          jeb->offset, ret);
                mutex_lock(&c->erase_free_sem);
                spin_lock(&c->erase_completion_lock);
                list_move(&jeb->list, &c->erase_pending_list);
                c->erasing_size -= c->sector_size;
                c->dirty_size += c->sector_size;
                jeb->dirty_size = c->sector_size;
                spin_unlock(&c->erase_completion_lock);
                mutex_unlock(&c->erase_free_sem);
                return;
        }

        if (ret == -EROFS)
                pr_warn("Erase at 0x%08x failed immediately: -EROFS. Is the sector locked?\n",
                        jeb->offset);
        else
                pr_warn("Erase at 0x%08x failed immediately: errno %d\n",
                        jeb->offset, ret);

        jffs2_erase_failed(c, jeb, bad_offset);
}

int jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count)
{
        struct jffs2_eraseblock *jeb;
        int work_done = 0;

        mutex_lock(&c->erase_free_sem);

        spin_lock(&c->erase_completion_lock);

        while (!list_empty(&c->erase_complete_list) ||
               !list_empty(&c->erase_pending_list)) {

                if (!list_empty(&c->erase_complete_list)) {
                        jeb = list_entry(c->erase_complete_list.next, struct jffs2_eraseblock, list);
                        list_move(&jeb->list, &c->erase_checking_list);
                        spin_unlock(&c->erase_completion_lock);
                        mutex_unlock(&c->erase_free_sem);
                        jffs2_mark_erased_block(c, jeb);

                        work_done++;
                        if (!--count) {
                                jffs2_dbg(1, "Count reached. jffs2_erase_pending_blocks leaving\n");
                                goto done;
                        }

                } else if (!list_empty(&c->erase_pending_list)) {
                        jeb = list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list);
                        jffs2_dbg(1, "Starting erase of pending block 0x%08x\n",
                                  jeb->offset);
                        list_del(&jeb->list);
                        c->erasing_size += c->sector_size;
                        c->wasted_size -= jeb->wasted_size;
                        c->free_size -= jeb->free_size;
                        c->used_size -= jeb->used_size;
                        c->dirty_size -= jeb->dirty_size;
                        jeb->wasted_size = jeb->used_size = jeb->dirty_size = jeb->free_size = 0;
                        jffs2_free_jeb_node_refs(c, jeb);
                        list_add(&jeb->list, &c->erasing_list);
                        spin_unlock(&c->erase_completion_lock);
                        mutex_unlock(&c->erase_free_sem);

                        jffs2_erase_block(c, jeb);

                } else {
                        BUG();
                }

                /* Be nice */
                cond_resched();
                mutex_lock(&c->erase_free_sem);
                spin_lock(&c->erase_completion_lock);
        }

        spin_unlock(&c->erase_completion_lock);
        mutex_unlock(&c->erase_free_sem);
 done:
        jffs2_dbg(1, "jffs2_erase_pending_blocks completed\n");
        return work_done;
}

static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
        jffs2_dbg(1, "Erase completed successfully at 0x%08x\n", jeb->offset);
        mutex_lock(&c->erase_free_sem);
        spin_lock(&c->erase_completion_lock);
        list_move_tail(&jeb->list, &c->erase_complete_list);
        /* Wake the GC thread to mark them clean */
        jffs2_garbage_collect_trigger(c);
        spin_unlock(&c->erase_completion_lock);
        mutex_unlock(&c->erase_free_sem);
        wake_up(&c->erase_wait);
}

static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
{
        /* For NAND, if the failure did not occur at the device level for a
           specific physical page, don't bother updating the bad block table. */
        if (jffs2_cleanmarker_oob(c) && (bad_offset != (uint32_t)MTD_FAIL_ADDR_UNKNOWN)) {
                /* We had a device-level failure to erase.  Let's see if we've
                   failed too many times. */
                if (!jffs2_write_nand_badblock(c, jeb, bad_offset)) {
                        /* We'd like to give this block another try. */
                        mutex_lock(&c->erase_free_sem);
                        spin_lock(&c->erase_completion_lock);
                        list_move(&jeb->list, &c->erase_pending_list);
                        c->erasing_size -= c->sector_size;
                        c->dirty_size += c->sector_size;
                        jeb->dirty_size = c->sector_size;
                        spin_unlock(&c->erase_completion_lock);
                        mutex_unlock(&c->erase_free_sem);
                        return;
                }
        }

        mutex_lock(&c->erase_free_sem);
        spin_lock(&c->erase_completion_lock);
        c->erasing_size -= c->sector_size;
        c->bad_size += c->sector_size;
        list_move(&jeb->list, &c->bad_list);
        c->nr_erasing_blocks--;
        spin_unlock(&c->erase_completion_lock);
        mutex_unlock(&c->erase_free_sem);
        wake_up(&c->erase_wait);
}

/* Hmmm. Maybe we should accept the extra space it takes and make
   this a standard doubly-linked list? */
static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
                        struct jffs2_raw_node_ref *ref, struct jffs2_eraseblock *jeb)
{
        struct jffs2_inode_cache *ic = NULL;
        struct jffs2_raw_node_ref **prev;

        prev = &ref->next_in_ino;

        /* Walk the inode's list once, removing any nodes from this eraseblock */
        while (1) {
                if (!(*prev)->next_in_ino) {
                        /* We're looking at the jffs2_inode_cache, which is
                           at the end of the linked list. Stash it and continue
                           from the beginning of the list */
                        ic = (struct jffs2_inode_cache *)(*prev);
                        prev = &ic->nodes;
                        continue;
                }

                if (SECTOR_ADDR((*prev)->flash_offset) == jeb->offset) {
                        /* It's in the block we're erasing */
                        struct jffs2_raw_node_ref *this;

                        this = *prev;
                        *prev = this->next_in_ino;
                        this->next_in_ino = NULL;

                        if (this == ref)
                                break;

                        continue;
                }
                /* Not to be deleted. Skip */
                prev = &((*prev)->next_in_ino);
        }

        /* PARANOIA */
        if (!ic) {
                JFFS2_WARNING("inode_cache/xattr_datum/xattr_ref"
                              " not found in remove_node_refs()!!\n");
                return;
        }

        jffs2_dbg(1, "Removed nodes in range 0x%08x-0x%08x from ino #%u\n",
                  jeb->offset, jeb->offset + c->sector_size, ic->ino);

        D2({
                int i=0;
                struct jffs2_raw_node_ref *this;
                printk(KERN_DEBUG "After remove_node_refs_from_ino_list: \n");

                this = ic->nodes;

                printk(KERN_DEBUG);
                while(this) {
                        pr_cont("0x%08x(%d)->",
                               ref_offset(this), ref_flags(this));
                        if (++i == 5) {
                                printk(KERN_DEBUG);
                                i=0;
                        }
                        this = this->next_in_ino;
                }
                pr_cont("\n");
        });

        switch (ic->class) {
#ifdef CONFIG_JFFS2_FS_XATTR
                case RAWNODE_CLASS_XATTR_DATUM:
                        jffs2_release_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
                        break;
                case RAWNODE_CLASS_XATTR_REF:
                        jffs2_release_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
                        break;
#endif
                default:
                        if (ic->nodes == (void *)ic && ic->pino_nlink == 0)
                                jffs2_del_ino_cache(c, ic);
        }
}

void jffs2_free_jeb_node_refs(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
        struct jffs2_raw_node_ref *block, *ref;
        jffs2_dbg(1, "Freeing all node refs for eraseblock offset 0x%08x\n",
                  jeb->offset);

        block = ref = jeb->first_node;

        while (ref) {
                if (ref->flash_offset == REF_LINK_NODE) {
                        ref = ref->next_in_ino;
                        jffs2_free_refblock(block);
                        block = ref;
                        continue;
                }
                if (ref->flash_offset != REF_EMPTY_NODE && ref->next_in_ino)
                        jffs2_remove_node_refs_from_ino_list(c, ref, jeb);
                /* else it was a non-inode node or already removed, so don't bother */

                ref++;
        }
        jeb->first_node = jeb->last_node = NULL;
}

static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t *bad_offset)
{
        void *ebuf;
        uint32_t ofs;
        size_t retlen;
        int ret;
        unsigned long *wordebuf;

        ret = mtd_point(c->mtd, jeb->offset, c->sector_size, &retlen,
                        &ebuf, NULL);
        if (ret != -EOPNOTSUPP) {
                if (ret) {
                        jffs2_dbg(1, "MTD point failed %d\n", ret);
                        goto do_flash_read;
                }
                if (retlen < c->sector_size) {
                        /* Don't muck about if it won't let us point to the whole erase sector */
                        jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
                                  retlen);
                        mtd_unpoint(c->mtd, jeb->offset, retlen);
                        goto do_flash_read;
                }
                wordebuf = ebuf-sizeof(*wordebuf);
                retlen /= sizeof(*wordebuf);
                do {
                   if (*++wordebuf != ~0)
                           break;
                } while(--retlen);
                mtd_unpoint(c->mtd, jeb->offset, c->sector_size);
                if (retlen) {
                        pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08tx\n",
                                *wordebuf,
                                jeb->offset +
                                c->sector_size-retlen * sizeof(*wordebuf));
                        return -EIO;
                }
                return 0;
        }
 do_flash_read:
        ebuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!ebuf) {
                pr_warn("Failed to allocate page buffer for verifying erase at 0x%08x. Refiling\n",
                        jeb->offset);
                return -EAGAIN;
        }

        jffs2_dbg(1, "Verifying erase at 0x%08x\n", jeb->offset);

        for (ofs = jeb->offset; ofs < jeb->offset + c->sector_size; ) {
                uint32_t readlen = min((uint32_t)PAGE_SIZE, jeb->offset + c->sector_size - ofs);
                int i;

                *bad_offset = ofs;

                ret = mtd_read(c->mtd, ofs, readlen, &retlen, ebuf);
                if (ret) {
                        pr_warn("Read of newly-erased block at 0x%08x failed: %d. Putting on bad_list\n",
                                ofs, ret);
                        ret = -EIO;
                        goto fail;
                }
                if (retlen != readlen) {
                        pr_warn("Short read from newly-erased block at 0x%08x. Wanted %d, got %zd\n",
                                ofs, readlen, retlen);
                        ret = -EIO;
                        goto fail;
                }
                for (i=0; i<readlen; i += sizeof(unsigned long)) {
                        /* It's OK. We know it's properly aligned */
                        unsigned long *datum = ebuf + i;
                        if (*datum + 1) {
                                *bad_offset += i;
                                pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08x\n",
                                        *datum, *bad_offset);
                                ret = -EIO;
                                goto fail;
                        }
                }
                ofs += readlen;
                cond_resched();
        }
        ret = 0;
fail:
        kfree(ebuf);
        return ret;
}

static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
        size_t retlen;
        int ret;
        uint32_t bad_offset;

        switch (jffs2_block_check_erase(c, jeb, &bad_offset)) {
        case -EAGAIN:   goto refile;
        case -EIO:      goto filebad;
        }

        /* Write the erase complete marker */
        jffs2_dbg(1, "Writing erased marker to block at 0x%08x\n", jeb->offset);
        bad_offset = jeb->offset;

        /* Cleanmarker in oob area or no cleanmarker at all ? */
        if (jffs2_cleanmarker_oob(c) || c->cleanmarker_size == 0) {

                if (jffs2_cleanmarker_oob(c)) {
                        if (jffs2_write_nand_cleanmarker(c, jeb))
                                goto filebad;
                }
        } else {

                struct kvec vecs[1];
                struct jffs2_unknown_node marker = {
                        .magic =        cpu_to_je16(JFFS2_MAGIC_BITMASK),
                        .nodetype =     cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER),
                        .totlen =       cpu_to_je32(c->cleanmarker_size)
                };

                jffs2_prealloc_raw_node_refs(c, jeb, 1);

                marker.hdr_crc = cpu_to_je32(crc32(0, &marker, sizeof(struct jffs2_unknown_node)-4));

                vecs[0].iov_base = (unsigned char *) &marker;
                vecs[0].iov_len = sizeof(marker);
                ret = jffs2_flash_direct_writev(c, vecs, 1, jeb->offset, &retlen);

                if (ret || retlen != sizeof(marker)) {
                        if (ret)
                                pr_warn("Write clean marker to block at 0x%08x failed: %d\n",
                                       jeb->offset, ret);
                        else
                                pr_warn("Short write to newly-erased block at 0x%08x: Wanted %zd, got %zd\n",
                                       jeb->offset, sizeof(marker), retlen);

                        goto filebad;
                }
        }
        /* Everything else got zeroed before the erase */
        jeb->free_size = c->sector_size;

        mutex_lock(&c->erase_free_sem);
        spin_lock(&c->erase_completion_lock);

        c->erasing_size -= c->sector_size;
        c->free_size += c->sector_size;

        /* Account for cleanmarker now, if it's in-band */
        if (c->cleanmarker_size && !jffs2_cleanmarker_oob(c))
                jffs2_link_node_ref(c, jeb, jeb->offset | REF_NORMAL, c->cleanmarker_size, NULL);

        list_move_tail(&jeb->list, &c->free_list);
        c->nr_erasing_blocks--;
        c->nr_free_blocks++;

        jffs2_dbg_acct_sanity_check_nolock(c, jeb);
        jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

        spin_unlock(&c->erase_completion_lock);
        mutex_unlock(&c->erase_free_sem);
        wake_up(&c->erase_wait);
        return;

filebad:
        jffs2_erase_failed(c, jeb, bad_offset);
        return;

refile:
        /* Stick it back on the list from whence it came and come back later */
        mutex_lock(&c->erase_free_sem);
        spin_lock(&c->erase_completion_lock);
        jffs2_garbage_collect_trigger(c);
        list_move(&jeb->list, &c->erase_complete_list);
        spin_unlock(&c->erase_completion_lock);
        mutex_unlock(&c->erase_free_sem);
        return;
}