direct.c

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/*
 * direct.c - NILFS direct block pointer.
 *
 * 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/errno.h>
#include "nilfs.h"
#include "page.h"
#include "direct.h"
#include "alloc.h"
#include "dat.h"

static inline __le64 *nilfs_direct_dptrs(const struct nilfs_bmap *direct)
{
    return (__le64 *)
        ((struct nilfs_direct_node *)direct->b_u.u_data + 1);
}

static inline __u64
nilfs_direct_get_ptr(const struct nilfs_bmap *direct, __u64 key)
{
    return le64_to_cpu(*(nilfs_direct_dptrs(direct) + key));
}

static inline void nilfs_direct_set_ptr(struct nilfs_bmap *direct,
                    __u64 key, __u64 ptr)
{
    *(nilfs_direct_dptrs(direct) + key) = cpu_to_le64(ptr);
}

static int nilfs_direct_lookup(const struct nilfs_bmap *direct,
                   __u64 key, int level, __u64 *ptrp)
{
    __u64 ptr;

    if (key > NILFS_DIRECT_KEY_MAX || level != 1)
        return -ENOENT;
    ptr = nilfs_direct_get_ptr(direct, key);
    if (ptr == NILFS_BMAP_INVALID_PTR)
        return -ENOENT;

    *ptrp = ptr;
    return 0;
}

static int nilfs_direct_lookup_contig(const struct nilfs_bmap *direct,
                      __u64 key, __u64 *ptrp,
                      unsigned maxblocks)
{
    struct inode *dat = NULL;
    __u64 ptr, ptr2;
    sector_t blocknr;
    int ret, cnt;

    if (key > NILFS_DIRECT_KEY_MAX)
        return -ENOENT;
    ptr = nilfs_direct_get_ptr(direct, key);
    if (ptr == NILFS_BMAP_INVALID_PTR)
        return -ENOENT;

    if (NILFS_BMAP_USE_VBN(direct)) {
        dat = nilfs_bmap_get_dat(direct);
        ret = nilfs_dat_translate(dat, ptr, &blocknr);
        if (ret < 0)
            return ret;
        ptr = blocknr;
    }

    maxblocks = min_t(unsigned, maxblocks, NILFS_DIRECT_KEY_MAX - key + 1);
    for (cnt = 1; cnt < maxblocks &&
             (ptr2 = nilfs_direct_get_ptr(direct, key + cnt)) !=
             NILFS_BMAP_INVALID_PTR;
         cnt++) {
        if (dat) {
            ret = nilfs_dat_translate(dat, ptr2, &blocknr);
            if (ret < 0)
                return ret;
            ptr2 = blocknr;
        }
        if (ptr2 != ptr + cnt)
            break;
    }
    *ptrp = ptr;
    return cnt;
}

static __u64
nilfs_direct_find_target_v(const struct nilfs_bmap *direct, __u64 key)
{
    __u64 ptr;

    ptr = nilfs_bmap_find_target_seq(direct, key);
    if (ptr != NILFS_BMAP_INVALID_PTR)
        /* sequential access */
        return ptr;
    else
        /* block group */
        return nilfs_bmap_find_target_in_group(direct);
}

static int nilfs_direct_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
{
    union nilfs_bmap_ptr_req req;
    struct inode *dat = NULL;
    struct buffer_head *bh;
    int ret;

    if (key > NILFS_DIRECT_KEY_MAX)
        return -ENOENT;
    if (nilfs_direct_get_ptr(bmap, key) != NILFS_BMAP_INVALID_PTR)
        return -EEXIST;

    if (NILFS_BMAP_USE_VBN(bmap)) {
        req.bpr_ptr = nilfs_direct_find_target_v(bmap, key);
        dat = nilfs_bmap_get_dat(bmap);
    }
    ret = nilfs_bmap_prepare_alloc_ptr(bmap, &req, dat);
    if (!ret) {
        /* ptr must be a pointer to a buffer head. */
        bh = (struct buffer_head *)((unsigned long)ptr);
        set_buffer_nilfs_volatile(bh);

        nilfs_bmap_commit_alloc_ptr(bmap, &req, dat);
        nilfs_direct_set_ptr(bmap, key, req.bpr_ptr);

        if (!nilfs_bmap_dirty(bmap))
            nilfs_bmap_set_dirty(bmap);

        if (NILFS_BMAP_USE_VBN(bmap))
            nilfs_bmap_set_target_v(bmap, key, req.bpr_ptr);

        nilfs_inode_add_blocks(bmap->b_inode, 1);
    }
    return ret;
}

static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
{
    union nilfs_bmap_ptr_req req;
    struct inode *dat;
    int ret;

    if (key > NILFS_DIRECT_KEY_MAX ||
        nilfs_direct_get_ptr(bmap, key) == NILFS_BMAP_INVALID_PTR)
        return -ENOENT;

    dat = NILFS_BMAP_USE_VBN(bmap) ? nilfs_bmap_get_dat(bmap) : NULL;
    req.bpr_ptr = nilfs_direct_get_ptr(bmap, key);

    ret = nilfs_bmap_prepare_end_ptr(bmap, &req, dat);
    if (!ret) {
        nilfs_bmap_commit_end_ptr(bmap, &req, dat);
        nilfs_direct_set_ptr(bmap, key, NILFS_BMAP_INVALID_PTR);
        nilfs_inode_sub_blocks(bmap->b_inode, 1);
    }
    return ret;
}

static int nilfs_direct_last_key(const struct nilfs_bmap *direct, __u64 *keyp)
{
    __u64 key, lastkey;

    lastkey = NILFS_DIRECT_KEY_MAX + 1;
    for (key = NILFS_DIRECT_KEY_MIN; key <= NILFS_DIRECT_KEY_MAX; key++)
        if (nilfs_direct_get_ptr(direct, key) !=
            NILFS_BMAP_INVALID_PTR)
            lastkey = key;

    if (lastkey == NILFS_DIRECT_KEY_MAX + 1)
        return -ENOENT;

    *keyp = lastkey;

    return 0;
}

static int nilfs_direct_check_insert(const struct nilfs_bmap *bmap, __u64 key)
{
    return key > NILFS_DIRECT_KEY_MAX;
}

static int nilfs_direct_gather_data(struct nilfs_bmap *direct,
                    __u64 *keys, __u64 *ptrs, int nitems)
{
    __u64 key;
    __u64 ptr;
    int n;

    if (nitems > NILFS_DIRECT_NBLOCKS)
        nitems = NILFS_DIRECT_NBLOCKS;
    n = 0;
    for (key = 0; key < nitems; key++) {
        ptr = nilfs_direct_get_ptr(direct, key);
        if (ptr != NILFS_BMAP_INVALID_PTR) {
            keys[n] = key;
            ptrs[n] = ptr;
            n++;
        }
    }
    return n;
}

int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
                    __u64 key, __u64 *keys, __u64 *ptrs, int n)
{
    __le64 *dptrs;
    int ret, i, j;

    /* no need to allocate any resource for conversion */

    /* delete */
    ret = bmap->b_ops->bop_delete(bmap, key);
    if (ret < 0)
        return ret;

    /* free resources */
    if (bmap->b_ops->bop_clear != NULL)
        bmap->b_ops->bop_clear(bmap);

    /* convert */
    dptrs = nilfs_direct_dptrs(bmap);
    for (i = 0, j = 0; i < NILFS_DIRECT_NBLOCKS; i++) {
        if ((j < n) && (i == keys[j])) {
            dptrs[i] = (i != key) ?
                cpu_to_le64(ptrs[j]) :
                NILFS_BMAP_INVALID_PTR;
            j++;
        } else
            dptrs[i] = NILFS_BMAP_INVALID_PTR;
    }

    nilfs_direct_init(bmap);
    return 0;
}

static int nilfs_direct_propagate(struct nilfs_bmap *bmap,
                  struct buffer_head *bh)
{
    struct nilfs_palloc_req oldreq, newreq;
    struct inode *dat;
    __u64 key;
    __u64 ptr;
    int ret;

    if (!NILFS_BMAP_USE_VBN(bmap))
        return 0;

    dat = nilfs_bmap_get_dat(bmap);
    key = nilfs_bmap_data_get_key(bmap, bh);
    ptr = nilfs_direct_get_ptr(bmap, key);
    if (!buffer_nilfs_volatile(bh)) {
        oldreq.pr_entry_nr = ptr;
        newreq.pr_entry_nr = ptr;
        ret = nilfs_dat_prepare_update(dat, &oldreq, &newreq);
        if (ret < 0)
            return ret;
        nilfs_dat_commit_update(dat, &oldreq, &newreq,
                    bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
        set_buffer_nilfs_volatile(bh);
        nilfs_direct_set_ptr(bmap, key, newreq.pr_entry_nr);
    } else
        ret = nilfs_dat_mark_dirty(dat, ptr);

    return ret;
}

static int nilfs_direct_assign_v(struct nilfs_bmap *direct,
                 __u64 key, __u64 ptr,
                 struct buffer_head **bh,
                 sector_t blocknr,
                 union nilfs_binfo *binfo)
{
    struct inode *dat = nilfs_bmap_get_dat(direct);
    union nilfs_bmap_ptr_req req;
    int ret;

    req.bpr_ptr = ptr;
    ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
    if (!ret) {
        nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
        binfo->bi_v.bi_vblocknr = cpu_to_le64(ptr);
        binfo->bi_v.bi_blkoff = cpu_to_le64(key);
    }
    return ret;
}

static int nilfs_direct_assign_p(struct nilfs_bmap *direct,
                 __u64 key, __u64 ptr,
                 struct buffer_head **bh,
                 sector_t blocknr,
                 union nilfs_binfo *binfo)
{
    nilfs_direct_set_ptr(direct, key, blocknr);

    binfo->bi_dat.bi_blkoff = cpu_to_le64(key);
    binfo->bi_dat.bi_level = 0;

    return 0;
}

static int nilfs_direct_assign(struct nilfs_bmap *bmap,
                   struct buffer_head **bh,
                   sector_t blocknr,
                   union nilfs_binfo *binfo)
{
    __u64 key;
    __u64 ptr;

    key = nilfs_bmap_data_get_key(bmap, *bh);
    if (unlikely(key > NILFS_DIRECT_KEY_MAX)) {
        printk(KERN_CRIT "%s: invalid key: %llu\n", __func__,
               (unsigned long long)key);
        return -EINVAL;
    }
    ptr = nilfs_direct_get_ptr(bmap, key);
    if (unlikely(ptr == NILFS_BMAP_INVALID_PTR)) {
        printk(KERN_CRIT "%s: invalid pointer: %llu\n", __func__,
               (unsigned long long)ptr);
        return -EINVAL;
    }

    return NILFS_BMAP_USE_VBN(bmap) ?
        nilfs_direct_assign_v(bmap, key, ptr, bh, blocknr, binfo) :
        nilfs_direct_assign_p(bmap, key, ptr, bh, blocknr, binfo);
}

static const struct nilfs_bmap_operations nilfs_direct_ops = {
    .bop_lookup     =   nilfs_direct_lookup,
    .bop_lookup_contig  =   nilfs_direct_lookup_contig,
    .bop_insert     =   nilfs_direct_insert,
    .bop_delete     =   nilfs_direct_delete,
    .bop_clear      =   NULL,

    .bop_propagate      =   nilfs_direct_propagate,

    .bop_lookup_dirty_buffers   =   NULL,

    .bop_assign     =   nilfs_direct_assign,
    .bop_mark       =   NULL,

    .bop_last_key       =   nilfs_direct_last_key,
    .bop_check_insert   =   nilfs_direct_check_insert,
    .bop_check_delete   =   NULL,
    .bop_gather_data    =   nilfs_direct_gather_data,
};


int nilfs_direct_init(struct nilfs_bmap *bmap)
{
    bmap->b_ops = &nilfs_direct_ops;
    return 0;
}