[dragonfly.git] / sys / vfs / hammer / hammer_reblock.c

/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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
 * COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
 * 
 * $DragonFly: src/sys/vfs/hammer/hammer_reblock.c,v 1.32.2.1 2008/07/16 18:39:32 dillon Exp $
 */
/*
 * HAMMER reblocker - This code frees up fragmented physical space
 *
 * HAMMER only keeps track of free space on a big-block basis.  A big-block
 * containing holes can only be freed by migrating the remaining data in
 * that big-block into a new big-block, then freeing the big-block.
 *
 * This function is called from an ioctl or via the hammer support thread.
 */

#include "hammer.h"

static int hammer_reblock_helper(struct hammer_ioc_reblock *reblock,
                                 hammer_cursor_t cursor,
                                 hammer_btree_elm_t elm);
static int hammer_reblock_data(struct hammer_ioc_reblock *reblock,
                                hammer_cursor_t cursor, hammer_btree_elm_t elm);
static int hammer_reblock_leaf_node(struct hammer_ioc_reblock *reblock,
                                hammer_cursor_t cursor, hammer_btree_elm_t elm);
static int hammer_reblock_int_node(struct hammer_ioc_reblock *reblock,
                                hammer_cursor_t cursor, hammer_btree_elm_t elm);

int
hammer_ioc_reblock(hammer_transaction_t trans, hammer_inode_t ip,
               struct hammer_ioc_reblock *reblock)
{
        struct hammer_cursor cursor;
        hammer_btree_elm_t elm;
        int checkspace_count;
        int error;
        int seq;
        int slop;

        /*
         * A fill level <= 20% is considered an emergency.  free_level is
         * inverted from fill_level.
         */
        if (reblock->free_level >= HAMMER_LARGEBLOCK_SIZE * 8 / 10)
                slop = HAMMER_CHKSPC_EMERGENCY;
        else
                slop = HAMMER_CHKSPC_REBLOCK;

        if ((reblock->key_beg.localization | reblock->key_end.localization) &
            HAMMER_LOCALIZE_PSEUDOFS_MASK) {
                return(EINVAL);
        }
        if (reblock->key_beg.obj_id >= reblock->key_end.obj_id)
                return(EINVAL);
        if (reblock->free_level < 0)
                return(EINVAL);

        reblock->key_cur = reblock->key_beg;
        reblock->key_cur.localization &= HAMMER_LOCALIZE_MASK;
        reblock->key_cur.localization += ip->obj_localization;

        checkspace_count = 0;
        seq = trans->hmp->flusher.act;
retry:
        error = hammer_init_cursor(trans, &cursor, NULL, NULL);
        if (error) {
                hammer_done_cursor(&cursor);
                goto failed;
        }
        cursor.key_beg.localization = reblock->key_cur.localization;
        cursor.key_beg.obj_id = reblock->key_cur.obj_id;
        cursor.key_beg.key = HAMMER_MIN_KEY;
        cursor.key_beg.create_tid = 1;
        cursor.key_beg.delete_tid = 0;
        cursor.key_beg.rec_type = HAMMER_MIN_RECTYPE;
        cursor.key_beg.obj_type = 0;

        cursor.key_end.localization = (reblock->key_end.localization &
                                        HAMMER_LOCALIZE_MASK) +
                                      ip->obj_localization;
        cursor.key_end.obj_id = reblock->key_end.obj_id;
        cursor.key_end.key = HAMMER_MAX_KEY;
        cursor.key_end.create_tid = HAMMER_MAX_TID - 1;
        cursor.key_end.delete_tid = 0;
        cursor.key_end.rec_type = HAMMER_MAX_RECTYPE;
        cursor.key_end.obj_type = 0;

        cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE;
        cursor.flags |= HAMMER_CURSOR_BACKEND;

        /*
         * This flag allows the btree scan code to return internal nodes,
         * so we can reblock them in addition to the leafs.  Only specify it
         * if we intend to reblock B-Tree nodes.
         */
        if (reblock->head.flags & HAMMER_IOC_DO_BTREE)
                cursor.flags |= HAMMER_CURSOR_REBLOCKING;

        error = hammer_btree_first(&cursor);
        while (error == 0) {
                /*
                 * Internal or Leaf node
                 */
                elm = &cursor.node->ondisk->elms[cursor.index];
                reblock->key_cur.obj_id = elm->base.obj_id;
                reblock->key_cur.localization = elm->base.localization;

                /*
                 * Yield to more important tasks
                 */
                if ((error = hammer_signal_check(trans->hmp)) != 0)
                        break;

                /*
                 * If there is insufficient free space it may be due to
                 * reserved bigblocks, which flushing might fix.
                 */
                if (hammer_checkspace(trans->hmp, slop)) {
                        if (++checkspace_count == 10) {
                                error = ENOSPC;
                                break;
                        }
                        hammer_unlock_cursor(&cursor, 0);
                        hammer_flusher_wait(trans->hmp, seq);
                        hammer_lock_cursor(&cursor, 0);
                        seq = hammer_flusher_async(trans->hmp, NULL);
                        continue;
                }

                /*
                 * Acquiring the sync_lock prevents the operation from
                 * crossing a synchronization boundary.
                 *
                 * NOTE: cursor.node may have changed on return.
                 */
                hammer_sync_lock_sh(trans);
                error = hammer_reblock_helper(reblock, &cursor, elm);
                hammer_sync_unlock(trans);

                while (hammer_flusher_meta_halflimit(trans->hmp) ||
                       hammer_flusher_undo_exhausted(trans, 2)) {
                        hammer_unlock_cursor(&cursor, 0);
                        hammer_flusher_wait(trans->hmp, seq);
                        hammer_lock_cursor(&cursor, 0);
                        seq = hammer_flusher_async_one(trans->hmp);
                }

                /*
                 * Setup for iteration, our cursor flags may be modified by
                 * other threads while we are unlocked.
                 */
                cursor.flags |= HAMMER_CURSOR_ATEDISK;

                /*
                 * We allocate data buffers, which atm we don't track
                 * dirty levels for because we allow the kernel to write
                 * them.  But if we allocate too many we can still deadlock
                 * the buffer cache.
                 *
                 * (The cursor's node and element may change!)
                 */
                if (bd_heatup()) {
                        hammer_unlock_cursor(&cursor, 0);
                        bwillwrite(HAMMER_XBUFSIZE);
                        hammer_lock_cursor(&cursor, 0);
                }

                if (error == 0) {
                        error = hammer_btree_iterate(&cursor);
                }

        }
        if (error == ENOENT)
                error = 0;
        hammer_done_cursor(&cursor);
        if (error == EWOULDBLOCK) {
                hammer_flusher_sync(trans->hmp);
                goto retry;
        }
        if (error == EDEADLK)
                goto retry;
        if (error == EINTR) {
                reblock->head.flags |= HAMMER_IOC_HEAD_INTR;
                error = 0;
        }
failed:
        reblock->key_cur.localization &= HAMMER_LOCALIZE_MASK;
        return(error);
}

/*
 * Reblock the B-Tree (leaf) node, record, and/or data if necessary.
 *
 * XXX We have no visibility into internal B-Tree nodes at the moment,
 * only leaf nodes.
 */
static int
hammer_reblock_helper(struct hammer_ioc_reblock *reblock,
                      hammer_cursor_t cursor, hammer_btree_elm_t elm)
{
        hammer_mount_t hmp;
        hammer_off_t tmp_offset;
        int error;
        int bytes;
        int cur;
        int iocflags;

        error = 0;
        hmp = cursor->trans->hmp;

        /*
         * Reblock data.  Note that data embedded in a record is reblocked
         * by the record reblock code.  Data processing only occurs at leaf
         * nodes and for RECORD element types.
         */
        if (cursor->node->ondisk->type != HAMMER_BTREE_TYPE_LEAF)
                goto skip;
        if (elm->leaf.base.btype != HAMMER_BTREE_TYPE_RECORD)
                return(0);
        tmp_offset = elm->leaf.data_offset;
        if (tmp_offset == 0)
                goto skip;
        if (error)
                goto skip;

        /*
         * NOTE: Localization restrictions may also have been set-up, we can't
         * just set the match flags willy-nilly here.
         */
        switch(elm->leaf.base.rec_type) {
        case HAMMER_RECTYPE_INODE:
                iocflags = HAMMER_IOC_DO_INODES;
                break;
        case HAMMER_RECTYPE_EXT:
        case HAMMER_RECTYPE_FIX:
        case HAMMER_RECTYPE_PFS:
        case HAMMER_RECTYPE_DIRENTRY:
                iocflags = HAMMER_IOC_DO_DIRS;
                break;
        case HAMMER_RECTYPE_DATA:
        case HAMMER_RECTYPE_DB:
                iocflags = HAMMER_IOC_DO_DATA;
                break;
        default:
                iocflags = 0;
                break;
        }
        if (reblock->head.flags & iocflags) {
                ++reblock->data_count;
                reblock->data_byte_count += elm->leaf.data_len;
                bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
                if (hammer_debug_general & 0x4000)
                        kprintf("D %6d/%d\n", bytes, reblock->free_level);
                if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
                    bytes >= reblock->free_level) {
                        hammer_io_direct_uncache(hmp, &elm->leaf);
                        error = hammer_cursor_upgrade(cursor);
                        if (error == 0) {
                                error = hammer_reblock_data(reblock,
                                                            cursor, elm);
                        }
                        if (error == 0) {
                                ++reblock->data_moves;
                                reblock->data_byte_moves += elm->leaf.data_len;
                        }
                }
        }

skip:
        /*
         * Reblock a B-Tree internal or leaf node.
         */
        tmp_offset = cursor->node->node_offset;
        if (cursor->index == 0 &&
            error == 0 && (reblock->head.flags & HAMMER_IOC_DO_BTREE)) {
                ++reblock->btree_count;
                bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
                if (hammer_debug_general & 0x4000)
                        kprintf("B %6d/%d\n", bytes, reblock->free_level);
                if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
                    bytes >= reblock->free_level) {
                        error = hammer_cursor_upgrade(cursor);
                        if (error == 0) {
                                if (cursor->parent)
                                        elm = &cursor->parent->ondisk->elms[cursor->parent_index];
                                else
                                        elm = NULL;
                                switch(cursor->node->ondisk->type) {
                                case HAMMER_BTREE_TYPE_LEAF:
                                        error = hammer_reblock_leaf_node(
                                                        reblock, cursor, elm);
                                        break;
                                case HAMMER_BTREE_TYPE_INTERNAL:
                                        error = hammer_reblock_int_node(
                                                        reblock, cursor, elm);
                                        break;
                                default:
                                        panic("Illegal B-Tree node type");
                                }
                        }
                        if (error == 0) {
                                ++reblock->btree_moves;
                        }
                }
        }

        hammer_cursor_downgrade(cursor);
        return(error);
}

/*
 * Reblock a record's data.  Both the B-Tree element and record pointers
 * to the data must be adjusted.
 */
static int
hammer_reblock_data(struct hammer_ioc_reblock *reblock,
                    hammer_cursor_t cursor, hammer_btree_elm_t elm)
{
        struct hammer_buffer *data_buffer = NULL;
        hammer_off_t ndata_offset;
        int error;
        void *ndata;

        error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_DATA |
                                             HAMMER_CURSOR_GET_LEAF);
        if (error)
                return (error);
        ndata = hammer_alloc_data(cursor->trans, elm->leaf.data_len,
                                  elm->leaf.base.rec_type,
                                  &ndata_offset, &data_buffer, &error);
        if (error)
                goto done;

        /*
         * Move the data
         */
        hammer_modify_buffer(cursor->trans, data_buffer, NULL, 0);
        bcopy(cursor->data, ndata, elm->leaf.data_len);
        hammer_modify_buffer_done(data_buffer);

        hammer_blockmap_free(cursor->trans,
                             elm->leaf.data_offset, elm->leaf.data_len);

        hammer_modify_node(cursor->trans, cursor->node,
                           &elm->leaf.data_offset, sizeof(hammer_off_t));
        elm->leaf.data_offset = ndata_offset;
        hammer_modify_node_done(cursor->node);

done:
        if (data_buffer)
                hammer_rel_buffer(data_buffer, 0);
        return (error);
}

/*
 * Reblock a B-Tree leaf node.  The parent must be adjusted to point to
 * the new copy of the leaf node.
 *
 * elm is a pointer to the parent element pointing at cursor.node.
 */
static int
hammer_reblock_leaf_node(struct hammer_ioc_reblock *reblock,
                         hammer_cursor_t cursor, hammer_btree_elm_t elm)
{
        hammer_node_t onode;
        hammer_node_t nnode;
        int error;

        onode = cursor->node;
        nnode = hammer_alloc_btree(cursor->trans, &error);

        if (nnode == NULL)
                return (error);

        /*
         * Move the node
         */
        hammer_lock_ex(&nnode->lock);
        hammer_modify_node_noundo(cursor->trans, nnode);
        bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));

        if (elm) {
                /*
                 * We are not the root of the B-Tree 
                 */
                hammer_modify_node(cursor->trans, cursor->parent,
                                   &elm->internal.subtree_offset,
                                   sizeof(elm->internal.subtree_offset));
                elm->internal.subtree_offset = nnode->node_offset;
                hammer_modify_node_done(cursor->parent);
        } else {
                /*
                 * We are the root of the B-Tree
                 */
                hammer_volume_t volume;
                        
                volume = hammer_get_root_volume(cursor->trans->hmp, &error);
                KKASSERT(error == 0);

                hammer_modify_volume_field(cursor->trans, volume,
                                           vol0_btree_root);
                volume->ondisk->vol0_btree_root = nnode->node_offset;
                hammer_modify_volume_done(volume);
                hammer_rel_volume(volume, 0);
        }

        hammer_cursor_replaced_node(onode, nnode);
        hammer_delete_node(cursor->trans, onode);

        if (hammer_debug_general & 0x4000) {
                kprintf("REBLOCK LNODE %016llx -> %016llx\n",
                        onode->node_offset, nnode->node_offset);
        }
        hammer_modify_node_done(nnode);
        cursor->node = nnode;

        hammer_unlock(&onode->lock);
        hammer_rel_node(onode);

        return (error);
}

/*
 * Reblock a B-Tree internal node.  The parent must be adjusted to point to
 * the new copy of the internal node, and the node's children's parent
 * pointers must also be adjusted to point to the new copy.
 *
 * elm is a pointer to the parent element pointing at cursor.node.
 */
static int
hammer_reblock_int_node(struct hammer_ioc_reblock *reblock,
                         hammer_cursor_t cursor, hammer_btree_elm_t elm)
{
        hammer_node_locklist_t locklist = NULL;
        hammer_node_t onode;
        hammer_node_t nnode;
        int error;
        int i;

        error = hammer_btree_lock_children(cursor, &locklist);
        if (error)
                goto done;

        onode = cursor->node;
        nnode = hammer_alloc_btree(cursor->trans, &error);

        if (nnode == NULL)
                goto done;

        /*
         * Move the node.  Adjust the parent's pointer to us first.
         */
        hammer_lock_ex(&nnode->lock);
        hammer_modify_node_noundo(cursor->trans, nnode);
        bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));

        if (elm) {
                /*
                 * We are not the root of the B-Tree 
                 */
                hammer_modify_node(cursor->trans, cursor->parent,
                                   &elm->internal.subtree_offset,
                                   sizeof(elm->internal.subtree_offset));
                elm->internal.subtree_offset = nnode->node_offset;
                hammer_modify_node_done(cursor->parent);
        } else {
                /*
                 * We are the root of the B-Tree
                 */
                hammer_volume_t volume;
                        
                volume = hammer_get_root_volume(cursor->trans->hmp, &error);
                KKASSERT(error == 0);

                hammer_modify_volume_field(cursor->trans, volume,
                                           vol0_btree_root);
                volume->ondisk->vol0_btree_root = nnode->node_offset;
                hammer_modify_volume_done(volume);
                hammer_rel_volume(volume, 0);
        }

        /*
         * Now adjust our children's pointers to us.
         */
        for (i = 0; i < nnode->ondisk->count; ++i) {
                elm = &nnode->ondisk->elms[i];
                error = btree_set_parent(cursor->trans, nnode, elm);
                if (error)
                        panic("reblock internal node: fixup problem");
        }

        /*
         * Clean up.
         *
         * The new node replaces the current node in the cursor.  The cursor
         * expects it to be locked so leave it locked.  Discard onode.
         */
        hammer_cursor_replaced_node(onode, nnode);
        hammer_delete_node(cursor->trans, onode);

        if (hammer_debug_general & 0x4000) {
                kprintf("REBLOCK INODE %016llx -> %016llx\n",
                        onode->node_offset, nnode->node_offset);
        }
        hammer_modify_node_done(nnode);
        cursor->node = nnode;

        hammer_unlock(&onode->lock);
        hammer_rel_node(onode);

done:
        hammer_btree_unlock_children(&locklist);
        return (error);
}