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      1 /*	$NetBSD: chfs_erase.c,v 1.2 2012/10/19 12:44:39 ttoth Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2010 Department of Software Engineering,
      5  *		      University of Szeged, Hungary
      6  * Copyright (c) 2010 David Tengeri <dtengeri (at) inf.u-szeged.hu>
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to The NetBSD Foundation
     10  * by the Department of Software Engineering, University of Szeged, Hungary
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #include "chfs.h"
     35 
     36 
     37 /*
     38  * chfs_remap_leb - unmap and then map a leb
     39  *
     40  * Gets an eraseblock from the erasable queue, unmaps it through
     41  * EBH and maps another eraseblock to the same LNR.
     42  * EBH will find a free eraseblock if any or will erase one if there isn't any
     43  * free, just dirty block.
     44  *
     45  * Needs more brainstorming here.
     46  */
     47 int
     48 chfs_remap_leb(struct chfs_mount *chmp)
     49 {
     50 	int err;
     51 	struct chfs_eraseblock *cheb;
     52 	dbg("chfs_remap_leb\n");
     53 	uint32_t dirty, unchecked, used, free, wasted;
     54 
     55 	KASSERT(!rw_write_held(&chmp->chm_lock_wbuf));
     56 	KASSERT(mutex_owned(&chmp->chm_lock_mountfields));
     57 	KASSERT(mutex_owned(&chmp->chm_lock_sizes));
     58 
     59 	if (!chmp->chm_nr_erasable_blocks) {
     60 		//TODO
     61 		/* We don't have any erasable blocks, need to check if there are
     62 		 * blocks on erasable_pending_wbuf_queue, flush the data and then
     63 		 * we can remap it.
     64 		 * If there aren't any blocks on that list too, we need to GC?
     65 		 */
     66 		if (!TAILQ_EMPTY(&chmp->chm_erasable_pending_wbuf_queue)) {
     67 			cheb = TAILQ_FIRST(&chmp->chm_erasable_pending_wbuf_queue);
     68 			TAILQ_REMOVE(&chmp->chm_erasable_pending_wbuf_queue, cheb, queue);
     69 			if (chmp->chm_wbuf_len) {
     70 				mutex_exit(&chmp->chm_lock_sizes);
     71 				chfs_flush_pending_wbuf(chmp);
     72 				mutex_enter(&chmp->chm_lock_sizes);
     73 			}
     74 			TAILQ_INSERT_TAIL(&chmp->chm_erase_pending_queue, cheb, queue);
     75 			chmp->chm_nr_erasable_blocks++;
     76 		} else {
     77 			/* We can't delete any block. */
     78 			//FIXME should we return ENOSPC?
     79 			return ENOSPC;
     80 		}
     81 	}
     82 	cheb = TAILQ_FIRST(&chmp->chm_erase_pending_queue);
     83 	TAILQ_REMOVE(&chmp->chm_erase_pending_queue, cheb, queue);
     84 	chmp->chm_nr_erasable_blocks--;
     85 
     86 	dirty = cheb->dirty_size;
     87 	unchecked = cheb->unchecked_size;
     88 	used = cheb->used_size;
     89 	free = cheb->free_size;
     90 	wasted = cheb->wasted_size;
     91 
     92 	/* Free allocated node references for this eraseblock */
     93 	chfs_free_node_refs(cheb);
     94 
     95 	err = chfs_unmap_leb(chmp, cheb->lnr);
     96 	if (err)
     97 		return err;
     98 
     99 	err = chfs_map_leb(chmp, cheb->lnr);
    100 	if (err)
    101 		return err;
    102 	/* Reset state to default and change chmp sizes too */
    103 	chfs_change_size_dirty(chmp, cheb, -dirty);
    104 	chfs_change_size_unchecked(chmp, cheb, -unchecked);
    105 	chfs_change_size_used(chmp, cheb, -used);
    106 	chfs_change_size_free(chmp, cheb, chmp->chm_ebh->eb_size - free);
    107 	chfs_change_size_wasted(chmp, cheb, -wasted);
    108 
    109 	KASSERT(cheb->dirty_size == 0);
    110 	KASSERT(cheb->unchecked_size == 0);
    111 	KASSERT(cheb->used_size == 0);
    112 	KASSERT(cheb->free_size == chmp->chm_ebh->eb_size);
    113 	KASSERT(cheb->wasted_size == 0);
    114 
    115 	cheb->first_node = NULL;
    116 	cheb->last_node  = NULL;
    117 	/* put it to free_queue */
    118 	TAILQ_INSERT_TAIL(&chmp->chm_free_queue, cheb, queue);
    119 	chmp->chm_nr_free_blocks++;
    120 	dbg("remaped (free: %d, erasable: %d)\n", chmp->chm_nr_free_blocks, chmp->chm_nr_erasable_blocks);
    121 	KASSERT(!TAILQ_EMPTY(&chmp->chm_free_queue));
    122 
    123 	return 0;
    124 }
    125