/*	$NetBSD: chfs_build.c,v 1.2 2011/11/24 21:22:39 agc Exp $	*/

/*-
 * Copyright (c) 2010 Department of Software Engineering,
 *		      University of Szeged, Hungary
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by the Department of Software Engineering, University of Szeged, Hungary
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "chfs.h"
//#include </root/xipffs/netbsd.chfs/chfs.h>


void
chfs_calc_trigger_levels(struct chfs_mount *chmp)
{
	uint32_t size;

	chmp->chm_resv_blocks_deletion = 2;

	size = chmp->chm_ebh->flash_size / 50;  //2% of flash size
	size += chmp->chm_ebh->peb_nr * 100;
	size += chmp->chm_ebh->eb_size - 1;

	chmp->chm_resv_blocks_write =
	    chmp->chm_resv_blocks_deletion + (size / chmp->chm_ebh->eb_size);
	chmp->chm_resv_blocks_gctrigger = chmp->chm_resv_blocks_write + 1;
	chmp->chm_resv_blocks_gcmerge = chmp->chm_resv_blocks_deletion + 1;
	chmp->chm_vdirty_blocks_gctrigger = chmp->chm_resv_blocks_gctrigger * 10;

	chmp->chm_nospc_dirty =
	    chmp->chm_ebh->eb_size + (chmp->chm_ebh->flash_size / 100);
}


/**
 * chfs_build_set_vnodecache_nlink - set pvno and nlink in vnodecaches
 * @chmp: CHFS main descriptor structure
 * @vc: vnode cache
 * This function travels @vc's directory entries and sets the pvno and nlink
 * attribute of the vnode where the dirent's vno points.
 */
void
chfs_build_set_vnodecache_nlink(struct chfs_mount *chmp,
    struct chfs_vnode_cache *vc)
{
	struct chfs_dirent *fd;
	//dbg("set nlink\n");

//	for (fd = vc->scan_dirents; fd; fd = fd->next) {
	TAILQ_FOREACH(fd, &vc->scan_dirents, fds) {
		struct chfs_vnode_cache *child_vc;

		if (!fd->vno)
			continue;

		mutex_enter(&chmp->chm_lock_vnocache);
		child_vc = chfs_vnode_cache_get(chmp, fd->vno);
		mutex_exit(&chmp->chm_lock_vnocache);
		if (!child_vc) {
			chfs_mark_node_obsolete(chmp, fd->nref);
			continue;
		}
		if (fd->type == VDIR) {
			if (child_vc->nlink < 1)
				child_vc->nlink = 1;

			if (child_vc->pvno) {
				chfs_err("found a hard link: child dir: %s"
				    ", (vno: %llu) of dir vno: %llu\n",
				    fd->name, (unsigned long long)fd->vno,
				    (unsigned long long)vc->vno);
			} else {
				//dbg("child_vc->pvno =
				//	vc->vno; pvno = %d\n", child_vc->pvno);
				child_vc->pvno = vc->vno;
			}
		}
		child_vc->nlink++;
		//dbg("child_vc->nlink++;\n");
		//child_vc->nlink++;
		vc->nlink++;
	}
}

/**
 * chfs_build_remove_unlinked vnode
 */
/* static */
void
chfs_build_remove_unlinked_vnode(struct chfs_mount *chmp,
    struct chfs_vnode_cache *vc,
//    struct chfs_dirent **unlinked)
    struct chfs_dirent_list *unlinked)
{
	struct chfs_node_ref *nref;
	struct chfs_dirent *fd, *tmpfd;

	dbg("START\n");
	dbg("vno: %llu\n", (unsigned long long)vc->vno);

	nref = vc->dnode;
	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
	// The vnode cache is at the end of the data node's chain
	while (nref != (struct chfs_node_ref *)vc) {
		struct chfs_node_ref *next = nref->nref_next;
		dbg("mark dnode\n");
		chfs_mark_node_obsolete(chmp, nref);
		nref = next;
	}
	nref = vc->dirents;
	// The vnode cache is at the end of the dirent node's chain
	while (nref != (struct chfs_node_ref *)vc) {
		struct chfs_node_ref *next = nref->nref_next;
		dbg("mark dirent\n");
		chfs_mark_node_obsolete(chmp, nref);
		nref = next;
	}
	if (!TAILQ_EMPTY(&vc->scan_dirents)) {
		TAILQ_FOREACH_SAFE(fd, &vc->scan_dirents, fds, tmpfd) {
//		while (vc->scan_dirents) {
			struct chfs_vnode_cache *child_vc;
//			fd = vc->scan_dirents;
			dbg("dirent dump:\n");
			dbg(" ->vno:     %llu\n", (unsigned long long)fd->vno);
			dbg(" ->version: %llu\n", (unsigned long long)fd->version);
			dbg(" ->nhash:   0x%x\n", fd->nhash);
			dbg(" ->nsize:   %d\n", fd->nsize);
			dbg(" ->name:    %s\n", fd->name);
			dbg(" ->type:    %d\n", fd->type);
//			vc->scan_dirents = fd->next;
			TAILQ_REMOVE(&vc->scan_dirents, fd, fds);

			if (!fd->vno) {
				chfs_free_dirent(fd);
				continue;
			}
			mutex_enter(&chmp->chm_lock_vnocache);
			child_vc = chfs_vnode_cache_get(chmp, fd->vno);
			mutex_exit(&chmp->chm_lock_vnocache);
			if (!child_vc) {
				chfs_free_dirent(fd);
				continue;
			}
			/**
			 * Decrease nlink in child. If it is 0, add to unlinked
			 * dirents or just free it otherwise.
			 */
			child_vc->nlink--;

			if (!child_vc->nlink) {
				//dbg("nlink is 0\n");
//				fd->next = *unlinked;
//				*unlinked = fd;
				// XXX HEAD or TAIL?
				// original code did HEAD, but we could add
				// it to the TAIL easily with TAILQ.
				TAILQ_INSERT_TAIL(unlinked, fd, fds);
			} else {
				chfs_free_dirent(fd);
			}
		}
	} else {
		dbg("there are no scan dirents\n");
	}

	nref = vc->v;
	while ((struct chfs_vnode_cache *)nref != vc) {
		if (!CHFS_REF_OBSOLETE(nref))
			chfs_mark_node_obsolete(chmp, nref);
		nref = nref->nref_next;
	}

	mutex_enter(&chmp->chm_lock_vnocache);
	if (vc->vno != CHFS_ROOTINO)
		chfs_vnode_cache_set_state(chmp, vc, VNO_STATE_UNCHECKED);
	mutex_exit(&chmp->chm_lock_vnocache);
	dbg("END\n");
}

/**
 * chfs_build_filesystem - build in-memory representation of filesystem
 * @chmp: super block information
 *
 * Step 1:
 * This function scans through the eraseblocks mapped in EBH.
 * During scan builds up the map of vnodes and directory entries and puts them
 * into the vnode_cache.
 * Step 2:
 * Scans the directory tree and set the nlink in the vnode caches.
 * Step 3:
 * Scans vnode caches with nlink = 0
 */
int
chfs_build_filesystem(struct chfs_mount *chmp)
{
	int i,err = 0;
	struct chfs_vnode_cache *vc;
	struct chfs_dirent *fd, *tmpfd;
//	struct chfs_dirent *unlinked = NULL;
	struct chfs_node_ref **nref;
	struct chfs_dirent_list unlinked;
	struct chfs_vnode_cache *notregvc;

	TAILQ_INIT(&unlinked);

	mutex_enter(&chmp->chm_lock_mountfields);

	/**
	 * Step 1
	 */
	chmp->chm_flags |= CHFS_MP_FLAG_SCANNING;
	for (i = 0; i < chmp->chm_ebh->peb_nr; i++) {
		//dbg("processing block: %d\n", i);
		chmp->chm_blocks[i].lnr = i;
		chmp->chm_blocks[i].free_size = chmp->chm_ebh->eb_size;
		//If the LEB is add to free list skip it.
		if (chmp->chm_ebh->lmap[i] < 0) {
			//dbg("block %d is unmapped\n", i);
			TAILQ_INSERT_TAIL(&chmp->chm_free_queue,
			    &chmp->chm_blocks[i], queue);
			chmp->chm_nr_free_blocks++;
			continue;
		}

		err = chfs_scan_eraseblock(chmp, &chmp->chm_blocks[i]);
		switch (err) {
		case CHFS_BLK_STATE_FREE:
			chmp->chm_nr_free_blocks++;
			TAILQ_INSERT_TAIL(&chmp->chm_free_queue,
			    &chmp->chm_blocks[i], queue);
			break;
		case CHFS_BLK_STATE_CLEAN:
			TAILQ_INSERT_TAIL(&chmp->chm_clean_queue,
			    &chmp->chm_blocks[i], queue);
			break;
		case CHFS_BLK_STATE_PARTDIRTY:
			//dbg("free size: %d\n", chmp->chm_blocks[i].free_size);
			if (chmp->chm_blocks[i].free_size > chmp->chm_wbuf_pagesize &&
			    (!chmp->chm_nextblock ||
				chmp->chm_blocks[i].free_size >
				chmp->chm_nextblock->free_size)) {
				/* convert the old nextblock's free size to
				 * dirty and put it on a list */
				if (chmp->chm_nextblock) {
					err = chfs_close_eraseblock(chmp,
					    chmp->chm_nextblock);
					if (err)
						return err;
				}
				chmp->chm_nextblock = &chmp->chm_blocks[i];
			} else {
				/* convert the scanned block's free size to
				 * dirty and put it on a list */
				err = chfs_close_eraseblock(chmp,
				    &chmp->chm_blocks[i]);
				if (err)
					return err;
			}
			break;
		case CHFS_BLK_STATE_ALLDIRTY:
			/*
			 * The block has a valid EBH header, but it doesn't
			 * contain any valid data.
			 */
			TAILQ_INSERT_TAIL(&chmp->chm_erase_pending_queue,
			    &chmp->chm_blocks[i], queue);
			chmp->chm_nr_erasable_blocks++;
			break;
		default:
			/* It was an error, unknown  state */
			break;
		}

	}
	chmp->chm_flags &= ~CHFS_MP_FLAG_SCANNING;


	//TODO need bad block check (and bad block handling in EBH too!!)
	/* Now EBH only checks block is bad  during its scan operation.
	 * Need check at erase + write + read...
	 */

	/**
	 * Step 2
	 */
	chmp->chm_flags |= CHFS_MP_FLAG_BUILDING;
	for (i = 0; i < VNODECACHE_SIZE; i++) {
		vc = chmp->chm_vnocache_hash[i];
		while (vc) {
			dbg("vc->vno: %llu\n", (unsigned long long)vc->vno);
			if (!TAILQ_EMPTY(&vc->scan_dirents))
				chfs_build_set_vnodecache_nlink(chmp, vc);
			vc = vc->next;
		}
	}

	/**
	 * Step 3
	 * Scan for vnodes with 0 nlink.
	 */
	for (i =  0; i < VNODECACHE_SIZE; i++) {
		vc = chmp->chm_vnocache_hash[i];
		while (vc) {
			if (vc->nlink) {
				vc = vc->next;
				continue;
			}

			//dbg("remove unlinked start i: %d\n", i);
			chfs_build_remove_unlinked_vnode(chmp,
			    vc, &unlinked);
			//dbg("remove unlinked end\n");
			vc = vc->next;
		}
	}
	/* Remove the newly unlinked vnodes. They are on the unlinked list */
	TAILQ_FOREACH_SAFE(fd, &unlinked, fds, tmpfd) {
//	while (unlinked) {
//		fd = unlinked;
//		unlinked = fd->next;
		TAILQ_REMOVE(&unlinked, fd, fds);
		mutex_enter(&chmp->chm_lock_vnocache);
		vc = chfs_vnode_cache_get(chmp, fd->vno);
		mutex_exit(&chmp->chm_lock_vnocache);
		if (vc) {
			chfs_build_remove_unlinked_vnode(chmp,
			    vc, &unlinked);
		}
		chfs_free_dirent(fd);
	}

	chmp->chm_flags &= ~CHFS_MP_FLAG_BUILDING;

	/* Free all dirents */
	for (i =  0; i < VNODECACHE_SIZE; i++) {
		vc = chmp->chm_vnocache_hash[i];
		while (vc) {
			TAILQ_FOREACH_SAFE(fd, &vc->scan_dirents, fds, tmpfd) {
//			while (vc->scan_dirents) {
//				fd = vc->scan_dirents;
//				vc->scan_dirents = fd->next;
				TAILQ_REMOVE(&vc->scan_dirents, fd, fds);
				if (fd->vno == 0) {
					//for (nref = &vc->dirents;
					//     *nref != fd->nref;
					//     nref = &((*nref)->next));

					nref = &fd->nref;
					*nref = fd->nref->nref_next;
					//fd->nref->nref_next = NULL;
				} else if (fd->type == VDIR) {
					//set state every non-VREG file's vc
					mutex_enter(&chmp->chm_lock_vnocache);
					notregvc =
					    chfs_vnode_cache_get(chmp,
						fd->vno);
					chfs_vnode_cache_set_state(chmp,
					    notregvc, VNO_STATE_PRESENT);
					mutex_exit(&chmp->chm_lock_vnocache);
				}
				chfs_free_dirent(fd);
			}
//			vc->scan_dirents = NULL;
			KASSERT(TAILQ_EMPTY(&vc->scan_dirents));
			vc = vc->next;
		}
	}

	//Set up chmp->chm_wbuf_ofs for the first write
	if (chmp->chm_nextblock) {
		dbg("free_size: %d\n", chmp->chm_nextblock->free_size);
		chmp->chm_wbuf_ofs = chmp->chm_ebh->eb_size -
		    chmp->chm_nextblock->free_size;
	} else {
		chmp->chm_wbuf_ofs = 0xffffffff;
	}
	mutex_exit(&chmp->chm_lock_mountfields);

	return 0;
}