HAMMER - Implement experimental volume removal

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

/*
 * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com> and
 * Michael Neumann <mneumann@ntecs.de>
 *
 * 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.
 *
 */

#include "hammer.h"
#include <sys/fcntl.h>
#include <sys/nlookup.h>
#include <sys/buf.h>

static int
hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly);

static void
hammer_close_device(struct vnode **devvpp, int ronly);

static int
hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
        const char *vol_name, int vol_no, int vol_count,
        int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size);

static uint64_t
hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume);

static int
hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume);


int
hammer_ioc_volume_add(hammer_transaction_t trans, hammer_inode_t ip,
                struct hammer_ioc_volume *ioc)
{
        struct hammer_mount *hmp = trans->hmp;
        struct mount *mp = hmp->mp;
        hammer_volume_t volume;
        int error;

        if (mp->mnt_flag & MNT_RDONLY) {
                kprintf("Cannot add volume to read-only HAMMER filesystem\n");
                return (EINVAL);
        }

        if (hmp->nvolumes + 1 >= HAMMER_MAX_VOLUMES) {
                kprintf("Max number of HAMMER volumes exceeded\n");
                return (EINVAL);
        }

        /*
         * Find an unused volume number.
         */
        int free_vol_no = 0;
        while (free_vol_no < HAMMER_MAX_VOLUMES &&
               RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, free_vol_no)) {
                ++free_vol_no;
        }
        if (free_vol_no >= HAMMER_MAX_VOLUMES) {
                kprintf("Max number of HAMMER volumes exceeded\n");
                return (EINVAL);
        }

        struct vnode *devvp = NULL;
        error = hammer_setup_device(&devvp, ioc->device_name, 0);
        if (error)
                goto end;
        KKASSERT(devvp);
        error = hammer_format_volume_header(
                hmp,
                devvp,
                hmp->rootvol->ondisk->vol_name,
                free_vol_no,
                hmp->nvolumes+1,
                ioc->vol_size,
                ioc->boot_area_size,
                ioc->mem_area_size);
        hammer_close_device(&devvp, 0);
        if (error)
                goto end;

        error = hammer_install_volume(hmp, ioc->device_name, NULL);
        if (error)
                goto end;

        hammer_sync_lock_sh(trans);
        hammer_lock_ex(&hmp->blkmap_lock);

        ++hmp->nvolumes;

        /*
         * Set each volumes new value of the vol_count field.
         */
        for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
                if (vol_no == free_vol_no)
                        continue;

                volume = hammer_get_volume(hmp, vol_no, &error);
                if (volume == NULL && error == ENOENT) {
                        /*
                         * Skip unused volume numbers
                         */
                        error = 0;
                        continue;
                }
                KKASSERT(volume != NULL && error == 0);
                hammer_modify_volume_field(trans, volume, vol_count);
                volume->ondisk->vol_count = hmp->nvolumes;
                hammer_modify_volume_done(volume);
                hammer_rel_volume(volume, 0);
        }

        volume = hammer_get_volume(hmp, free_vol_no, &error);
        KKASSERT(volume != NULL && error == 0);

        uint64_t total_free_bigblocks =
                hammer_format_freemap(trans, volume);

        /*
         * Increase the total number of bigblocks
         */
        hammer_modify_volume_field(trans, trans->rootvol,
                vol0_stat_bigblocks);
        trans->rootvol->ondisk->vol0_stat_bigblocks += total_free_bigblocks;
        hammer_modify_volume_done(trans->rootvol);

        /*
         * Increase the number of free bigblocks
         * (including the copy in hmp)
         */
        hammer_modify_volume_field(trans, trans->rootvol,
                vol0_stat_freebigblocks);
        trans->rootvol->ondisk->vol0_stat_freebigblocks += total_free_bigblocks;
        hmp->copy_stat_freebigblocks =
                trans->rootvol->ondisk->vol0_stat_freebigblocks;
        hammer_modify_volume_done(trans->rootvol);

        hammer_rel_volume(volume, 0);

        hammer_unlock(&hmp->blkmap_lock);
        hammer_sync_unlock(trans);

end:
        if (error)
                kprintf("An error occurred: %d\n", error);
        return (error);
}


/*
 * Remove a volume.
 */
int
hammer_ioc_volume_del(hammer_transaction_t trans, hammer_inode_t ip,
                struct hammer_ioc_volume *ioc)
{
        struct hammer_mount *hmp = trans->hmp;
        struct mount *mp = hmp->mp;
        hammer_volume_t volume;
        int error = 0;

        if (mp->mnt_flag & MNT_RDONLY) {
                kprintf("Cannot del volume from read-only HAMMER filesystem\n");
                return (EINVAL);
        }


        volume = NULL;

        /*
         * find volume by volname
         */
        for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
                volume = hammer_get_volume(hmp, vol_no, &error);
                if (volume == NULL && error == ENOENT) {
                        /*
                         * Skip unused volume numbers
                         */
                        error = 0;
                        continue;
                }
                KKASSERT(volume != NULL && error == 0);
                if (strcmp(volume->vol_name, ioc->device_name) == 0) {
                        break;
                }
                volume = NULL;
        }

        if (!volume) {
                kprintf("Couldn't find volume\n");
                return (EINVAL);
        }

        if (volume == trans->rootvol) {
                kprintf("Cannot remove root-volume\n");
                hammer_rel_volume(volume, 0);
                return (EINVAL);
        }

        /*
         *
         */

        hmp->volume_to_remove = volume->vol_no;

        struct hammer_ioc_reblock reblock;
        bzero(&reblock, sizeof(reblock));

        reblock.key_beg.localization = HAMMER_MIN_LOCALIZATION;
        reblock.key_beg.obj_id = HAMMER_MIN_OBJID;
        reblock.key_end.localization = HAMMER_MAX_LOCALIZATION;
        reblock.key_end.obj_id = HAMMER_MAX_OBJID;
        //reblock.head.flags = flags & HAMMER_IOC_DO_FLAGS;
        reblock.free_level = HAMMER_LARGEBLOCK_SIZE;
        reblock.free_level = 0;

        error = hammer_ioc_reblock(trans, ip, &reblock);

        if (error) {
                kprintf("reblock failed: %d\n", error);
                hmp->volume_to_remove = -1;
                hammer_rel_volume(volume, 0);
                return (error);
        }

        hammer_sync_lock_sh(trans);
        hammer_lock_ex(&hmp->blkmap_lock);

        error = hammer_free_freemap(trans, volume);
        if (error) {
                kprintf("Failed to free volume\n");
                hmp->volume_to_remove = -1;
                hammer_rel_volume(volume, 0);
                hammer_unlock(&hmp->blkmap_lock);
                hammer_sync_unlock(trans);
                return (error);
        }

        hmp->volume_to_remove = -1;
        hammer_rel_volume(volume, 1);

        /* XXX: unload volume! */
        /*error = hammer_unload_volume(volume, NULL);
        if (error == -1) {
                kprintf("Failed to unload volume\n");
                hammer_unlock(&hmp->blkmap_lock);
                hammer_sync_unlock(trans);
                return (error);
        }*/

        --hmp->nvolumes;

        /*
         * Set each volume's new value of the vol_count field.
         */
        for (int vol_no = 0; vol_no < HAMMER_MAX_VOLUMES; ++vol_no) {
                volume = hammer_get_volume(hmp, vol_no, &error);
                if (volume == NULL && error == ENOENT) {
                        /*
                         * Skip unused volume numbers
                         */
                        error = 0;
                        continue;
                }
                KKASSERT(volume != NULL && error == 0);
                hammer_modify_volume_field(trans, volume, vol_count);
                volume->ondisk->vol_count = hmp->nvolumes;
                hammer_modify_volume_done(volume);
                hammer_rel_volume(volume, 0);
        }

        hammer_unlock(&hmp->blkmap_lock);
        hammer_sync_unlock(trans);

        return (0);
}


/*
 * Iterate over all usable L1 entries of the volume and
 * the corresponding L2 entries.
 */
static int
hammer_iterate_l1l2_entries(hammer_transaction_t trans, hammer_volume_t volume,
        int (*callback)(hammer_transaction_t, hammer_buffer_t *,
                struct hammer_blockmap_layer1*, struct hammer_blockmap_layer2 *,
                hammer_off_t, int, void *),
        void *data)
{
        struct hammer_mount *hmp = trans->hmp;
        hammer_blockmap_t freemap = &hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
        hammer_buffer_t buffer = NULL;
        int error = 0;

        hammer_off_t phys_off;
        hammer_off_t block_off;
        hammer_off_t layer1_off;
        hammer_off_t layer2_off;
        hammer_off_t aligned_buf_end_off;
        struct hammer_blockmap_layer1 *layer1;
        struct hammer_blockmap_layer2 *layer2;

        /*
         * Calculate the usable size of the volume, which
         * must be aligned at a bigblock (8 MB) boundary.
         */
        aligned_buf_end_off = (HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no,
                (volume->ondisk->vol_buf_end - volume->ondisk->vol_buf_beg)
                & ~HAMMER_LARGEBLOCK_MASK64));

        /*
         * Iterate the volume's address space in chunks of 4 TB, where each
         * chunk consists of at least one physically available 8 MB bigblock.
         *
         * For each chunk we need one L1 entry and one L2 bigblock.
         * We use the first bigblock of each chunk as L2 block.
         */
        for (phys_off = HAMMER_ENCODE_RAW_BUFFER(volume->ondisk->vol_no, 0);
             phys_off < aligned_buf_end_off;
             phys_off += HAMMER_BLOCKMAP_LAYER2) {
                for (block_off = 0;
                     block_off < HAMMER_BLOCKMAP_LAYER2;
                     block_off += HAMMER_LARGEBLOCK_SIZE) {
                        layer2_off = phys_off +
                                HAMMER_BLOCKMAP_LAYER2_OFFSET(block_off);
                        layer2 = hammer_bread(hmp, layer2_off, &error,
                                                &buffer);
                        if (error)
                                goto end;

                        int zone;
                        if (block_off == 0) {
                                /*
                                 * The first entry represents the L2 bigblock
                                 * itself.
                                 */
                                zone = HAMMER_ZONE_FREEMAP_INDEX;
                        } else if (phys_off + block_off < aligned_buf_end_off) {
                                /*
                                 * Available bigblock
                                 */
                                zone = 0;
                        } else {
                                /*
                                 * Bigblock outside of physically available
                                 * space
                                 */
                                zone = HAMMER_ZONE_UNAVAIL_INDEX;
                        }

                        error = callback(trans, &buffer, NULL, layer2, 0, zone,
                                        data);
                        if (error)
                                goto end;
                }

                layer1_off = freemap->phys_offset +
                                HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_off);
                layer1 = hammer_bread(hmp, layer1_off, &error, &buffer);
                if (error)
                        goto end;

                error = callback(trans, &buffer, layer1, NULL, phys_off, 0,
                                data);
                if (error)
                        goto end;
        }

end:
        if (buffer) {
                hammer_rel_buffer(buffer, 0);
                buffer = NULL;
        }

        return error;
}

struct format_bigblock_stat {
        uint64_t total_free_bigblocks;
        uint64_t free_bigblocks;
};

static int
format_callback(hammer_transaction_t trans, hammer_buffer_t *bufferp,
        struct hammer_blockmap_layer1 *layer1,
        struct hammer_blockmap_layer2 *layer2,
        hammer_off_t phys_off,
        int layer2_zone,
        void *data)
{
        struct format_bigblock_stat *stat = (struct format_bigblock_stat*)data;

        if (layer1) {
                KKASSERT(layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL);

                hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
                bzero(layer1, sizeof(layer1));
                layer1->phys_offset = phys_off;
                layer1->blocks_free = stat->free_bigblocks;
                layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
                hammer_modify_buffer_done(*bufferp);

                stat->total_free_bigblocks += stat->free_bigblocks;
                stat->free_bigblocks = 0; /* reset */
        } else if (layer2) {
                hammer_modify_buffer(trans, *bufferp, layer2, sizeof(*layer2));
                bzero(layer2, sizeof(*layer2));

                layer2->zone = layer2_zone;

                switch (layer2->zone) {
                case HAMMER_ZONE_FREEMAP_INDEX:
                        /*
                         * The first entry represents the L2 bigblock itself.
                         */
                        layer2->append_off = HAMMER_LARGEBLOCK_SIZE;
                        layer2->bytes_free = 0;
                        break;

                case 0:
                        /*
                         * Available bigblock
                         */
                        layer2->append_off = 0;
                        layer2->bytes_free = HAMMER_LARGEBLOCK_SIZE;
                        ++stat->free_bigblocks;
                        break;

                case HAMMER_ZONE_UNAVAIL_INDEX:
                        /*
                         * Bigblock outside of physically available space
                         */
                        layer2->append_off = HAMMER_LARGEBLOCK_SIZE;
                        layer2->bytes_free = 0;
                        break;
                default:
                        KKASSERT(0);
                }

                layer2->entry_crc = crc32(layer2, HAMMER_LAYER2_CRCSIZE);
                hammer_modify_buffer_done(*bufferp);
        } else {
                KKASSERT(0);
        }

        return 0;
}

static uint64_t
hammer_format_freemap(hammer_transaction_t trans, hammer_volume_t volume)
{
        int error = 0;

        struct format_bigblock_stat stat;
        stat.total_free_bigblocks = 0;
        stat.free_bigblocks = 0;

        error = hammer_iterate_l1l2_entries(trans, volume, format_callback,
                                        (void*)&stat);
        KKASSERT(error == 0);

        return stat.total_free_bigblocks;
}

static int
free_callback(hammer_transaction_t trans, hammer_buffer_t *bufferp,
        struct hammer_blockmap_layer1 *layer1,
        struct hammer_blockmap_layer2 *layer2,
        hammer_off_t phys_off,
        int layer2_zone,
        void *data __unused)
{
        if (layer1) {
                /*
                 * Free the L1 entry
                 */
                hammer_modify_buffer(trans, *bufferp, layer1, sizeof(*layer1));
                bzero(layer1, sizeof(layer1));
                layer1->phys_offset = HAMMER_BLOCKMAP_UNAVAIL;
                layer1->layer1_crc = crc32(layer1, HAMMER_LAYER1_CRCSIZE);
                hammer_modify_buffer_done(*bufferp);

                return 0;
        } else if (layer2) {
                switch (layer2_zone) {
                case HAMMER_ZONE_FREEMAP_INDEX:
                case HAMMER_ZONE_UNAVAIL_INDEX:
                        return 0;
                case 0:
                        if (layer2->append_off == 0 &&
                            layer2->bytes_free == HAMMER_LARGEBLOCK_SIZE) {
                                return 0;
                        } else {
                                return EINVAL; /* FIXME */
                        }
                default:
                        return EINVAL;  /* FIXME */
                }
        } else {
                KKASSERT(0);
        }

        return EINVAL;
}

static int
hammer_free_freemap(hammer_transaction_t trans, hammer_volume_t volume)
{
        return hammer_iterate_l1l2_entries(trans, volume, free_callback, NULL);
}

/************************************************************************
 *                              MISC                                    *
 ************************************************************************
 */

static int
hammer_setup_device(struct vnode **devvpp, const char *dev_path, int ronly)
{
        int error;
        struct nlookupdata nd;

        /*
         * Get the device vnode
         */
        if (*devvpp == NULL) {
                error = nlookup_init(&nd, dev_path, UIO_SYSSPACE, NLC_FOLLOW);
                if (error == 0)
                        error = nlookup(&nd);
                if (error == 0)
                        error = cache_vref(&nd.nl_nch, nd.nl_cred, devvpp);
                nlookup_done(&nd);
        } else {
                error = 0;
        }

        if (error == 0) {
                if (vn_isdisk(*devvpp, &error)) {
                        error = vfs_mountedon(*devvpp);
                }
        }
        if (error == 0 && vcount(*devvpp) > 0)
                error = EBUSY;
        if (error == 0) {
                vn_lock(*devvpp, LK_EXCLUSIVE | LK_RETRY);
                error = vinvalbuf(*devvpp, V_SAVE, 0, 0);
                if (error == 0) {
                        error = VOP_OPEN(*devvpp,
                                         (ronly ? FREAD : FREAD|FWRITE),
                                         FSCRED, NULL);
                }
                vn_unlock(*devvpp);
        }
        if (error && *devvpp) {
                vrele(*devvpp);
                *devvpp = NULL;
        }
        return (error);
}

static void
hammer_close_device(struct vnode **devvpp, int ronly)
{
        VOP_CLOSE(*devvpp, (ronly ? FREAD : FREAD|FWRITE));
        if (*devvpp) {
                vinvalbuf(*devvpp, ronly ? 0 : V_SAVE, 0, 0);
                vrele(*devvpp);
                *devvpp = NULL;
        }
}

static int
hammer_format_volume_header(struct hammer_mount *hmp, struct vnode *devvp,
        const char *vol_name, int vol_no, int vol_count,
        int64_t vol_size, int64_t boot_area_size, int64_t mem_area_size)
{
        struct buf *bp = NULL;
        struct hammer_volume_ondisk *ondisk;
        int error;

        /*
         * Extract the volume number from the volume header and do various
         * sanity checks.
         */
        KKASSERT(HAMMER_BUFSIZE >= sizeof(struct hammer_volume_ondisk));
        error = bread(devvp, 0LL, HAMMER_BUFSIZE, &bp);
        if (error || bp->b_bcount < sizeof(struct hammer_volume_ondisk))
                goto late_failure;

        ondisk = (struct hammer_volume_ondisk*) bp->b_data;

        /*
         * Note that we do NOT allow to use a device that contains
         * a valid HAMMER signature. It has to be cleaned up with dd
         * before.
         */
        if (ondisk->vol_signature == HAMMER_FSBUF_VOLUME) {
                kprintf("hammer_volume_add: Formatting of valid HAMMER volume "
                        "%s denied. Erase with dd!\n", vol_name);
                error = EFTYPE;
                goto late_failure;
        }

        bzero(ondisk, sizeof(struct hammer_volume_ondisk));
        ksnprintf(ondisk->vol_name, sizeof(ondisk->vol_name), "%s", vol_name);
        ondisk->vol_fstype = hmp->rootvol->ondisk->vol_fstype;
        ondisk->vol_signature = HAMMER_FSBUF_VOLUME;
        ondisk->vol_fsid = hmp->fsid;
        ondisk->vol_rootvol = hmp->rootvol->vol_no;
        ondisk->vol_no = vol_no;
        ondisk->vol_count = vol_count;
        ondisk->vol_version = hmp->version;

        /*
         * Reserve space for (future) header junk, setup our poor-man's
         * bigblock allocator.
         */
        int64_t vol_alloc = HAMMER_BUFSIZE * 16;

        ondisk->vol_bot_beg = vol_alloc;
        vol_alloc += boot_area_size;
        ondisk->vol_mem_beg = vol_alloc;
        vol_alloc += mem_area_size;

        /*
         * The remaining area is the zone 2 buffer allocation area.  These
         * buffers
         */
        ondisk->vol_buf_beg = vol_alloc;
        ondisk->vol_buf_end = vol_size & ~(int64_t)HAMMER_BUFMASK;

        if (ondisk->vol_buf_end < ondisk->vol_buf_beg) {
                kprintf("volume %d %s is too small to hold the volume header",
                     ondisk->vol_no, ondisk->vol_name);
                error = EFTYPE;
                goto late_failure;
        }

        ondisk->vol_nblocks = (ondisk->vol_buf_end - ondisk->vol_buf_beg) /
                              HAMMER_BUFSIZE;
        ondisk->vol_blocksize = HAMMER_BUFSIZE;

        /*
         * Write volume header to disk
         */
        error = bwrite(bp);
        bp = NULL;

late_failure:
        if (bp)
                brelse(bp);
        return (error);
}