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/*

 * JFFS2 -- Journalling Flash File System, Version 2.

 *

 * Copyright (C) 2001-2003 Red Hat, Inc.

 *

 * Created by David Woodhouse <dwmw2@infradead.org>

 *

 * For licensing information, see the file 'LICENCE' in this directory.

 *

 * $Id: build.c,v 1.75 2005/07/22 10:32:07 dedekind Exp $

 *

 */

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/mtd/mtd.h>

#include "nodelist.h"

static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, struct jffs2_inode_cache *, struct jffs2_full_dirent **);

static inline struct jffs2_inode_cache *

first_inode_chain(int *i, struct jffs2_sb_info *c)

{

        for (; *i < INOCACHE_HASHSIZE; (*i)++) {

                if (c->inocache_list[*i])

                        return c->inocache_list[*i];

        }

        return NULL;

}

static inline struct jffs2_inode_cache *

next_inode(int *i, struct jffs2_inode_cache *ic, struct jffs2_sb_info *c)

{

        /* More in this chain? */

        if (ic->next)

                return ic->next;

        (*i)++;

        return first_inode_chain(i, c);

}

#define for_each_inode(i, c, ic)                        \

        for (i = 0, ic = first_inode_chain(&i, (c));     \

             ic;                                        \

             ic = next_inode(&i, ic, (c)))

static inline void jffs2_build_inode_pass1(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)

{

        struct jffs2_full_dirent *fd;

        D1(printk(KERN_DEBUG "jffs2_build_inode building directory inode #%u\n", ic->ino));

        /* For each child, increase nlink */

        for(fd = ic->scan_dents; fd; fd = fd->next) {

                struct jffs2_inode_cache *child_ic;

                if (!fd->ino)

                        continue;

                /* XXX: Can get high latency here with huge directories */

                child_ic = jffs2_get_ino_cache(c, fd->ino);

                if (!child_ic) {

                        printk(KERN_NOTICE "Eep. Child \"%s\" (ino #%u) of dir ino #%u doesn't exist!\n",

                                  fd->name, fd->ino, ic->ino);

                        jffs2_mark_node_obsolete(c, fd->raw);

                        continue;

                }

                if (child_ic->nlink++ && fd->type == DT_DIR) {

                        printk(KERN_NOTICE "Child dir \"%s\" (ino #%u) of dir ino #%u appears to be a hard link\n", fd->name, fd->ino, ic->ino);

                        if (fd->ino == 1 && ic->ino == 1) {

                                printk(KERN_NOTICE "This is mostly harmless, and probably caused by creating a JFFS2 image\n");

                                printk(KERN_NOTICE "using a buggy version of mkfs.jffs2. Use at least v1.17.\n");

                        }

                        /* What do we do about it? */

                }

                D1(printk(KERN_DEBUG "Increased nlink for child \"%s\" (ino #%u)\n", fd->name, fd->ino));

                /* Can't free them. We might need them in pass 2 */

        }

}

/* Scan plan:

 - Scan physical nodes. Build map of inodes/dirents. Allocate inocaches as we go

 - Scan directory tree from top down, setting nlink in inocaches

 - Scan inocaches for inodes with nlink==0

*/

static int jffs2_build_filesystem(struct jffs2_sb_info *c)

{

        int ret;

        int i;

        struct jffs2_inode_cache *ic;

        struct jffs2_full_dirent *fd;

        struct jffs2_full_dirent *dead_fds = NULL;

        /* First, scan the medium and build all the inode caches with

           lists of physical nodes */

        c->flags |= JFFS2_SB_FLAG_SCANNING;

        ret = jffs2_scan_medium(c);

        c->flags &= ~JFFS2_SB_FLAG_SCANNING;

        if (ret)

                goto exit;

        D1(printk(KERN_DEBUG "Scanned flash completely\n"));

        jffs2_dbg_dump_block_lists_nolock(c);

        c->flags |= JFFS2_SB_FLAG_BUILDING;

        /* Now scan the directory tree, increasing nlink according to every dirent found. */

        for_each_inode(i, c, ic) {

                D1(printk(KERN_DEBUG "Pass 1: ino #%u\n", ic->ino));

                D1(BUG_ON(ic->ino > c->highest_ino));

                if (ic->scan_dents) {

                        jffs2_build_inode_pass1(c, ic);

                        cond_resched();

                }

        }

        D1(printk(KERN_DEBUG "Pass 1 complete\n"));

        /* Next, scan for inodes with nlink == 0 and remove them. If

           they were directories, then decrement the nlink of their

           children too, and repeat the scan. As that's going to be

           a fairly uncommon occurrence, it's not so evil to do it this

           way. Recursion bad. */

        D1(printk(KERN_DEBUG "Pass 2 starting\n"));

        for_each_inode(i, c, ic) {

                D1(printk(KERN_DEBUG "Pass 2: ino #%u, nlink %d, ic %p, nodes %p\n", ic->ino, ic->nlink, ic, ic->nodes));

                if (ic->nlink)

                        continue;

                jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);

                cond_resched();

        }

        D1(printk(KERN_DEBUG "Pass 2a starting\n"));

        while (dead_fds) {

                fd = dead_fds;

                dead_fds = fd->next;

                ic = jffs2_get_ino_cache(c, fd->ino);

                D1(printk(KERN_DEBUG "Removing dead_fd ino #%u (\"%s\"), ic at %p\n", fd->ino, fd->name, ic));

                if (ic)

                        jffs2_build_remove_unlinked_inode(c, ic, &dead_fds);

                jffs2_free_full_dirent(fd);

        }

        D1(printk(KERN_DEBUG "Pass 2 complete\n"));

        /* Finally, we can scan again and free the dirent structs */

        for_each_inode(i, c, ic) {

                D1(printk(KERN_DEBUG "Pass 3: ino #%u, ic %p, nodes %p\n", ic->ino, ic, ic->nodes));

                while(ic->scan_dents) {

                        fd = ic->scan_dents;

                        ic->scan_dents = fd->next;

                        jffs2_free_full_dirent(fd);

                }

                ic->scan_dents = NULL;

                cond_resched();

        }

        c->flags &= ~JFFS2_SB_FLAG_BUILDING;

        D1(printk(KERN_DEBUG "Pass 3 complete\n"));

        jffs2_dbg_dump_block_lists_nolock(c);

        /* Rotate the lists by some number to ensure wear levelling */

        jffs2_rotate_lists(c);

        ret = 0;

exit:

        if (ret) {

                for_each_inode(i, c, ic) {

                        while(ic->scan_dents) {

                                fd = ic->scan_dents;

                                ic->scan_dents = fd->next;

                                jffs2_free_full_dirent(fd);

                        }

                }

        }

        return ret;

}

static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic, struct jffs2_full_dirent **dead_fds)

{

        struct jffs2_raw_node_ref *raw;

        struct jffs2_full_dirent *fd;

        D1(printk(KERN_DEBUG "JFFS2: Removing ino #%u with nlink == zero.\n", ic->ino));

        raw = ic->nodes;

        while (raw != (void *)ic) {

                struct jffs2_raw_node_ref *next = raw->next_in_ino;

                D1(printk(KERN_DEBUG "obsoleting node at 0x%08x\n", ref_offset(raw)));

                jffs2_mark_node_obsolete(c, raw);

                raw = next;

        }

        if (ic->scan_dents) {

                int whinged = 0;

                D1(printk(KERN_DEBUG "Inode #%u was a directory which may have children...\n", ic->ino));

                while(ic->scan_dents) {

                        struct jffs2_inode_cache *child_ic;

                        fd = ic->scan_dents;

                        ic->scan_dents = fd->next;

                        if (!fd->ino) {

                                /* It's a deletion dirent. Ignore it */

                                D1(printk(KERN_DEBUG "Child \"%s\" is a deletion dirent, skipping...\n", fd->name));

                                jffs2_free_full_dirent(fd);

                                continue;

                        }

                        if (!whinged) {

                                whinged = 1;

                                printk(KERN_NOTICE "Inode #%u was a directory with children - removing those too...\n", ic->ino);

                        }

                        D1(printk(KERN_DEBUG "Removing child \"%s\", ino #%u\n",

                                  fd->name, fd->ino));

                        child_ic = jffs2_get_ino_cache(c, fd->ino);

                        if (!child_ic) {

                                printk(KERN_NOTICE "Cannot remove child \"%s\", ino #%u, because it doesn't exist\n", fd->name, fd->ino);

                                jffs2_free_full_dirent(fd);

                                continue;

                        }

                        /* Reduce nlink of the child. If it's now zero, stick it on the

                           dead_fds list to be cleaned up later. Else just free the fd */

                        child_ic->nlink--;

                        if (!child_ic->nlink) {

                                D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got zero nlink. Adding to dead_fds list.\n",

                                          fd->ino, fd->name));

                                fd->next = *dead_fds;

                                *dead_fds = fd;

                        } else {

                                D1(printk(KERN_DEBUG "Inode #%u (\"%s\") has now got nlink %d. Ignoring.\n",

                                          fd->ino, fd->name, child_ic->nlink));

                                jffs2_free_full_dirent(fd);

                        }

                }

        }

        /*

           We don't delete the inocache from the hash list and free it yet.

           The erase code will do that, when all the nodes are completely gone.

        */

}

static void jffs2_calc_trigger_levels(struct jffs2_sb_info *c)

{

        uint32_t size;

        /* Deletion should almost _always_ be allowed. We're fairly

           buggered once we stop allowing people to delete stuff

           because there's not enough free space... */

        c->resv_blocks_deletion = 2;

        /* Be conservative about how much space we need before we allow writes.

           On top of that which is required for deletia, require an extra 2%

           of the medium to be available, for overhead caused by nodes being

           split across blocks, etc. */

        size = c->flash_size / 50; /* 2% of flash size */

        size += c->nr_blocks * 100; /* And 100 bytes per eraseblock */

        size += c->sector_size - 1; /* ... and round up */

        c->resv_blocks_write = c->resv_blocks_deletion + (size / c->sector_size);

        /* When do we let the GC thread run in the background */

        c->resv_blocks_gctrigger = c->resv_blocks_write + 1;

        /* When do we allow garbage collection to merge nodes to make

           long-term progress at the expense of short-term space exhaustion? */

        c->resv_blocks_gcmerge = c->resv_blocks_deletion + 1;

        /* When do we allow garbage collection to eat from bad blocks rather

           than actually making progress? */

        c->resv_blocks_gcbad = 0;//c->resv_blocks_deletion + 2;

        /* If there's less than this amount of dirty space, don't bother

           trying to GC to make more space. It'll be a fruitless task */

        c->nospc_dirty_size = c->sector_size + (c->flash_size / 100);

        D1(printk(KERN_DEBUG "JFFS2 trigger levels (size %d KiB, block size %d KiB, %d blocks)\n",

                  c->flash_size / 1024, c->sector_size / 1024, c->nr_blocks));

        D1(printk(KERN_DEBUG "Blocks required to allow deletion:    %d (%d KiB)\n",

                  c->resv_blocks_deletion, c->resv_blocks_deletion*c->sector_size/1024));

        D1(printk(KERN_DEBUG "Blocks required to allow writes:      %d (%d KiB)\n",

                  c->resv_blocks_write, c->resv_blocks_write*c->sector_size/1024));

        D1(printk(KERN_DEBUG "Blocks required to quiesce GC thread: %d (%d KiB)\n",

                  c->resv_blocks_gctrigger, c->resv_blocks_gctrigger*c->sector_size/1024));

        D1(printk(KERN_DEBUG "Blocks required to allow GC merges:   %d (%d KiB)\n",

                  c->resv_blocks_gcmerge, c->resv_blocks_gcmerge*c->sector_size/1024));

        D1(printk(KERN_DEBUG "Blocks required to GC bad blocks:     %d (%d KiB)\n",

                  c->resv_blocks_gcbad, c->resv_blocks_gcbad*c->sector_size/1024));

        D1(printk(KERN_DEBUG "Amount of dirty space required to GC: %d bytes\n",

                  c->nospc_dirty_size));

}

int jffs2_do_mount_fs(struct jffs2_sb_info *c)

{

        int i;

        c->free_size = c->flash_size;

        c->nr_blocks = c->flash_size / c->sector_size;

#ifndef __ECOS

        if (c->mtd->flags & MTD_NO_VIRTBLOCKS)

                c->blocks = vmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks);

        else

#endif

                c->blocks = kmalloc(sizeof(struct jffs2_eraseblock) * c->nr_blocks, GFP_KERNEL);

        if (!c->blocks)

                return -ENOMEM;

        for (i=0; i<c->nr_blocks; i++) {

                INIT_LIST_HEAD(&c->blocks[i].list);

                c->blocks[i].offset = i * c->sector_size;

                c->blocks[i].free_size = c->sector_size;

                c->blocks[i].dirty_size = 0;

                c->blocks[i].wasted_size = 0;

                c->blocks[i].unchecked_size = 0;

                c->blocks[i].used_size = 0;

                c->blocks[i].first_node = NULL;

                c->blocks[i].last_node = NULL;

                c->blocks[i].bad_count = 0;

        }

        INIT_LIST_HEAD(&c->clean_list);

        INIT_LIST_HEAD(&c->very_dirty_list);

        INIT_LIST_HEAD(&c->dirty_list);

        INIT_LIST_HEAD(&c->erasable_list);

        INIT_LIST_HEAD(&c->erasing_list);

        INIT_LIST_HEAD(&c->erase_pending_list);

        INIT_LIST_HEAD(&c->erasable_pending_wbuf_list);

        INIT_LIST_HEAD(&c->erase_complete_list);

        INIT_LIST_HEAD(&c->free_list);

        INIT_LIST_HEAD(&c->bad_list);

        INIT_LIST_HEAD(&c->bad_used_list);

        c->highest_ino = 1;

        if (jffs2_build_filesystem(c)) {

                D1(printk(KERN_DEBUG "build_fs failed\n"));

                jffs2_free_ino_caches(c);

                jffs2_free_raw_node_refs(c);

#ifndef __ECOS

                if (c->mtd->flags & MTD_NO_VIRTBLOCKS)

                    vfree(c->blocks);

                else

#endif

                    kfree(c->blocks);

                return -EIO;

        }

        jffs2_calc_trigger_levels(c);

        return 0;

}