dat.c

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/*
 * dat.c - NILFS disk address translation.
 *
 * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Written by Koji Sato <[email protected]>.
 */

#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/string.h>
#include <linux/errno.h>
#include "nilfs.h"
#include "mdt.h"
#include "alloc.h"
#include "dat.h"


#define NILFS_CNO_MIN   ((__u64)1)
#define NILFS_CNO_MAX   (~(__u64)0)

struct nilfs_dat_info {
    struct nilfs_mdt_info mi;
    struct nilfs_palloc_cache palloc_cache;
    struct nilfs_shadow_map shadow;
};

static inline struct nilfs_dat_info *NILFS_DAT_I(struct inode *dat)
{
    return (struct nilfs_dat_info *)NILFS_MDT(dat);
}

static int nilfs_dat_prepare_entry(struct inode *dat,
                   struct nilfs_palloc_req *req, int create)
{
    return nilfs_palloc_get_entry_block(dat, req->pr_entry_nr,
                        create, &req->pr_entry_bh);
}

static void nilfs_dat_commit_entry(struct inode *dat,
                   struct nilfs_palloc_req *req)
{
    mark_buffer_dirty(req->pr_entry_bh);
    nilfs_mdt_mark_dirty(dat);
    brelse(req->pr_entry_bh);
}

static void nilfs_dat_abort_entry(struct inode *dat,
                  struct nilfs_palloc_req *req)
{
    brelse(req->pr_entry_bh);
}

int nilfs_dat_prepare_alloc(struct inode *dat, struct nilfs_palloc_req *req)
{
    int ret;

    ret = nilfs_palloc_prepare_alloc_entry(dat, req);
    if (ret < 0)
        return ret;

    ret = nilfs_dat_prepare_entry(dat, req, 1);
    if (ret < 0)
        nilfs_palloc_abort_alloc_entry(dat, req);

    return ret;
}

void nilfs_dat_commit_alloc(struct inode *dat, struct nilfs_palloc_req *req)
{
    struct nilfs_dat_entry *entry;
    void *kaddr;

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    entry->de_start = cpu_to_le64(NILFS_CNO_MIN);
    entry->de_end = cpu_to_le64(NILFS_CNO_MAX);
    entry->de_blocknr = cpu_to_le64(0);
    kunmap_atomic(kaddr);

    nilfs_palloc_commit_alloc_entry(dat, req);
    nilfs_dat_commit_entry(dat, req);
}

void nilfs_dat_abort_alloc(struct inode *dat, struct nilfs_palloc_req *req)
{
    nilfs_dat_abort_entry(dat, req);
    nilfs_palloc_abort_alloc_entry(dat, req);
}

static void nilfs_dat_commit_free(struct inode *dat,
                  struct nilfs_palloc_req *req)
{
    struct nilfs_dat_entry *entry;
    void *kaddr;

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    entry->de_start = cpu_to_le64(NILFS_CNO_MIN);
    entry->de_end = cpu_to_le64(NILFS_CNO_MIN);
    entry->de_blocknr = cpu_to_le64(0);
    kunmap_atomic(kaddr);

    nilfs_dat_commit_entry(dat, req);
    nilfs_palloc_commit_free_entry(dat, req);
}

int nilfs_dat_prepare_start(struct inode *dat, struct nilfs_palloc_req *req)
{
    int ret;

    ret = nilfs_dat_prepare_entry(dat, req, 0);
    WARN_ON(ret == -ENOENT);
    return ret;
}

void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
                sector_t blocknr)
{
    struct nilfs_dat_entry *entry;
    void *kaddr;

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    entry->de_start = cpu_to_le64(nilfs_mdt_cno(dat));
    entry->de_blocknr = cpu_to_le64(blocknr);
    kunmap_atomic(kaddr);

    nilfs_dat_commit_entry(dat, req);
}

int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
{
    struct nilfs_dat_entry *entry;
    __u64 start;
    sector_t blocknr;
    void *kaddr;
    int ret;

    ret = nilfs_dat_prepare_entry(dat, req, 0);
    if (ret < 0) {
        WARN_ON(ret == -ENOENT);
        return ret;
    }

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    start = le64_to_cpu(entry->de_start);
    blocknr = le64_to_cpu(entry->de_blocknr);
    kunmap_atomic(kaddr);

    if (blocknr == 0) {
        ret = nilfs_palloc_prepare_free_entry(dat, req);
        if (ret < 0) {
            nilfs_dat_abort_entry(dat, req);
            return ret;
        }
    }

    return 0;
}

void nilfs_dat_commit_end(struct inode *dat, struct nilfs_palloc_req *req,
              int dead)
{
    struct nilfs_dat_entry *entry;
    __u64 start, end;
    sector_t blocknr;
    void *kaddr;

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    end = start = le64_to_cpu(entry->de_start);
    if (!dead) {
        end = nilfs_mdt_cno(dat);
        WARN_ON(start > end);
    }
    entry->de_end = cpu_to_le64(end);
    blocknr = le64_to_cpu(entry->de_blocknr);
    kunmap_atomic(kaddr);

    if (blocknr == 0)
        nilfs_dat_commit_free(dat, req);
    else
        nilfs_dat_commit_entry(dat, req);
}

void nilfs_dat_abort_end(struct inode *dat, struct nilfs_palloc_req *req)
{
    struct nilfs_dat_entry *entry;
    __u64 start;
    sector_t blocknr;
    void *kaddr;

    kaddr = kmap_atomic(req->pr_entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
                         req->pr_entry_bh, kaddr);
    start = le64_to_cpu(entry->de_start);
    blocknr = le64_to_cpu(entry->de_blocknr);
    kunmap_atomic(kaddr);

    if (start == nilfs_mdt_cno(dat) && blocknr == 0)
        nilfs_palloc_abort_free_entry(dat, req);
    nilfs_dat_abort_entry(dat, req);
}

int nilfs_dat_prepare_update(struct inode *dat,
                 struct nilfs_palloc_req *oldreq,
                 struct nilfs_palloc_req *newreq)
{
    int ret;

    ret = nilfs_dat_prepare_end(dat, oldreq);
    if (!ret) {
        ret = nilfs_dat_prepare_alloc(dat, newreq);
        if (ret < 0)
            nilfs_dat_abort_end(dat, oldreq);
    }
    return ret;
}

void nilfs_dat_commit_update(struct inode *dat,
                 struct nilfs_palloc_req *oldreq,
                 struct nilfs_palloc_req *newreq, int dead)
{
    nilfs_dat_commit_end(dat, oldreq, dead);
    nilfs_dat_commit_alloc(dat, newreq);
}

void nilfs_dat_abort_update(struct inode *dat,
                struct nilfs_palloc_req *oldreq,
                struct nilfs_palloc_req *newreq)
{
    nilfs_dat_abort_end(dat, oldreq);
    nilfs_dat_abort_alloc(dat, newreq);
}

int nilfs_dat_mark_dirty(struct inode *dat, __u64 vblocknr)
{
    struct nilfs_palloc_req req;
    int ret;

    req.pr_entry_nr = vblocknr;
    ret = nilfs_dat_prepare_entry(dat, &req, 0);
    if (ret == 0)
        nilfs_dat_commit_entry(dat, &req);
    return ret;
}

int nilfs_dat_freev(struct inode *dat, __u64 *vblocknrs, size_t nitems)
{
    return nilfs_palloc_freev(dat, vblocknrs, nitems);
}

int nilfs_dat_move(struct inode *dat, __u64 vblocknr, sector_t blocknr)
{
    struct buffer_head *entry_bh;
    struct nilfs_dat_entry *entry;
    void *kaddr;
    int ret;

    ret = nilfs_palloc_get_entry_block(dat, vblocknr, 0, &entry_bh);
    if (ret < 0)
        return ret;

    /*
     * The given disk block number (blocknr) is not yet written to
     * the device at this point.
     *
     * To prevent nilfs_dat_translate() from returning the
     * uncommitted block number, this makes a copy of the entry
     * buffer and redirects nilfs_dat_translate() to the copy.
     */
    if (!buffer_nilfs_redirected(entry_bh)) {
        ret = nilfs_mdt_freeze_buffer(dat, entry_bh);
        if (ret) {
            brelse(entry_bh);
            return ret;
        }
    }

    kaddr = kmap_atomic(entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
    if (unlikely(entry->de_blocknr == cpu_to_le64(0))) {
        printk(KERN_CRIT "%s: vbn = %llu, [%llu, %llu)\n", __func__,
               (unsigned long long)vblocknr,
               (unsigned long long)le64_to_cpu(entry->de_start),
               (unsigned long long)le64_to_cpu(entry->de_end));
        kunmap_atomic(kaddr);
        brelse(entry_bh);
        return -EINVAL;
    }
    WARN_ON(blocknr == 0);
    entry->de_blocknr = cpu_to_le64(blocknr);
    kunmap_atomic(kaddr);

    mark_buffer_dirty(entry_bh);
    nilfs_mdt_mark_dirty(dat);

    brelse(entry_bh);

    return 0;
}

int nilfs_dat_translate(struct inode *dat, __u64 vblocknr, sector_t *blocknrp)
{
    struct buffer_head *entry_bh, *bh;
    struct nilfs_dat_entry *entry;
    sector_t blocknr;
    void *kaddr;
    int ret;

    ret = nilfs_palloc_get_entry_block(dat, vblocknr, 0, &entry_bh);
    if (ret < 0)
        return ret;

    if (!nilfs_doing_gc() && buffer_nilfs_redirected(entry_bh)) {
        bh = nilfs_mdt_get_frozen_buffer(dat, entry_bh);
        if (bh) {
            WARN_ON(!buffer_uptodate(bh));
            brelse(entry_bh);
            entry_bh = bh;
        }
    }

    kaddr = kmap_atomic(entry_bh->b_page);
    entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
    blocknr = le64_to_cpu(entry->de_blocknr);
    if (blocknr == 0) {
        ret = -ENOENT;
        goto out;
    }
    *blocknrp = blocknr;

 out:
    kunmap_atomic(kaddr);
    brelse(entry_bh);
    return ret;
}

ssize_t nilfs_dat_get_vinfo(struct inode *dat, void *buf, unsigned visz,
                size_t nvi)
{
    struct buffer_head *entry_bh;
    struct nilfs_dat_entry *entry;
    struct nilfs_vinfo *vinfo = buf;
    __u64 first, last;
    void *kaddr;
    unsigned long entries_per_block = NILFS_MDT(dat)->mi_entries_per_block;
    int i, j, n, ret;

    for (i = 0; i < nvi; i += n) {
        ret = nilfs_palloc_get_entry_block(dat, vinfo->vi_vblocknr,
                           0, &entry_bh);
        if (ret < 0)
            return ret;
        kaddr = kmap_atomic(entry_bh->b_page);
        /* last virtual block number in this block */
        first = vinfo->vi_vblocknr;
        do_div(first, entries_per_block);
        first *= entries_per_block;
        last = first + entries_per_block - 1;
        for (j = i, n = 0;
             j < nvi && vinfo->vi_vblocknr >= first &&
                 vinfo->vi_vblocknr <= last;
             j++, n++, vinfo = (void *)vinfo + visz) {
            entry = nilfs_palloc_block_get_entry(
                dat, vinfo->vi_vblocknr, entry_bh, kaddr);
            vinfo->vi_start = le64_to_cpu(entry->de_start);
            vinfo->vi_end = le64_to_cpu(entry->de_end);
            vinfo->vi_blocknr = le64_to_cpu(entry->de_blocknr);
        }
        kunmap_atomic(kaddr);
        brelse(entry_bh);
    }

    return nvi;
}

int nilfs_dat_read(struct super_block *sb, size_t entry_size,
           struct nilfs_inode *raw_inode, struct inode **inodep)
{
    static struct lock_class_key dat_lock_key;
    struct inode *dat;
    struct nilfs_dat_info *di;
    int err;

    dat = nilfs_iget_locked(sb, NULL, NILFS_DAT_INO);
    if (unlikely(!dat))
        return -ENOMEM;
    if (!(dat->i_state & I_NEW))
        goto out;

    err = nilfs_mdt_init(dat, NILFS_MDT_GFP, sizeof(*di));
    if (err)
        goto failed;

    err = nilfs_palloc_init_blockgroup(dat, entry_size);
    if (err)
        goto failed;

    di = NILFS_DAT_I(dat);
    lockdep_set_class(&di->mi.mi_sem, &dat_lock_key);
    nilfs_palloc_setup_cache(dat, &di->palloc_cache);
    nilfs_mdt_setup_shadow_map(dat, &di->shadow);

    err = nilfs_read_inode_common(dat, raw_inode);
    if (err)
        goto failed;

    unlock_new_inode(dat);
 out:
    *inodep = dat;
    return 0;
 failed:
    iget_failed(dat);
    return err;
}