recovery.c

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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "glops.h"
#include "lops.h"
#include "meta_io.h"
#include "recovery.h"
#include "super.h"
#include "util.h"
#include "dir.h"

struct workqueue_struct *gfs_recovery_wq;

int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
               struct buffer_head **bh)
{
    struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
    struct gfs2_glock *gl = ip->i_gl;
    int new = 0;
    u64 dblock;
    u32 extlen;
    int error;

    error = gfs2_extent_map(&ip->i_inode, blk, &new, &dblock, &extlen);
    if (error)
        return error;
    if (!dblock) {
        gfs2_consist_inode(ip);
        return -EIO;
    }

    *bh = gfs2_meta_ra(gl, dblock, extlen);

    return error;
}

int gfs2_revoke_add(struct gfs2_sbd *sdp, u64 blkno, unsigned int where)
{
    struct list_head *head = &sdp->sd_revoke_list;
    struct gfs2_revoke_replay *rr;
    int found = 0;

    list_for_each_entry(rr, head, rr_list) {
        if (rr->rr_blkno == blkno) {
            found = 1;
            break;
        }
    }

    if (found) {
        rr->rr_where = where;
        return 0;
    }

    rr = kmalloc(sizeof(struct gfs2_revoke_replay), GFP_NOFS);
    if (!rr)
        return -ENOMEM;

    rr->rr_blkno = blkno;
    rr->rr_where = where;
    list_add(&rr->rr_list, head);

    return 1;
}

int gfs2_revoke_check(struct gfs2_sbd *sdp, u64 blkno, unsigned int where)
{
    struct gfs2_revoke_replay *rr;
    int wrap, a, b, revoke;
    int found = 0;

    list_for_each_entry(rr, &sdp->sd_revoke_list, rr_list) {
        if (rr->rr_blkno == blkno) {
            found = 1;
            break;
        }
    }

    if (!found)
        return 0;

    wrap = (rr->rr_where < sdp->sd_replay_tail);
    a = (sdp->sd_replay_tail < where);
    b = (where < rr->rr_where);
    revoke = (wrap) ? (a || b) : (a && b);

    return revoke;
}

void gfs2_revoke_clean(struct gfs2_sbd *sdp)
{
    struct list_head *head = &sdp->sd_revoke_list;
    struct gfs2_revoke_replay *rr;

    while (!list_empty(head)) {
        rr = list_entry(head->next, struct gfs2_revoke_replay, rr_list);
        list_del(&rr->rr_list);
        kfree(rr);
    }
}

static int gfs2_log_header_in(struct gfs2_log_header_host *lh, const void *buf)
{
    const struct gfs2_log_header *str = buf;

    if (str->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||
        str->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH))
        return 1;

    lh->lh_sequence = be64_to_cpu(str->lh_sequence);
    lh->lh_flags = be32_to_cpu(str->lh_flags);
    lh->lh_tail = be32_to_cpu(str->lh_tail);
    lh->lh_blkno = be32_to_cpu(str->lh_blkno);
    lh->lh_hash = be32_to_cpu(str->lh_hash);
    return 0;
}

static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
              struct gfs2_log_header_host *head)
{
    struct buffer_head *bh;
    struct gfs2_log_header_host uninitialized_var(lh);
    const u32 nothing = 0;
    u32 hash;
    int error;

    error = gfs2_replay_read_block(jd, blk, &bh);
    if (error)
        return error;

    hash = crc32_le((u32)~0, bh->b_data, sizeof(struct gfs2_log_header) -
                         sizeof(u32));
    hash = crc32_le(hash, (unsigned char const *)&nothing, sizeof(nothing));
    hash ^= (u32)~0;
    error = gfs2_log_header_in(&lh, bh->b_data);
    brelse(bh);

    if (error || lh.lh_blkno != blk || lh.lh_hash != hash)
        return 1;

    *head = lh;

    return 0;
}

static int find_good_lh(struct gfs2_jdesc *jd, unsigned int *blk,
            struct gfs2_log_header_host *head)
{
    unsigned int orig_blk = *blk;
    int error;

    for (;;) {
        error = get_log_header(jd, *blk, head);
        if (error <= 0)
            return error;

        if (++*blk == jd->jd_blocks)
            *blk = 0;

        if (*blk == orig_blk) {
            gfs2_consist_inode(GFS2_I(jd->jd_inode));
            return -EIO;
        }
    }
}

static int jhead_scan(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
    unsigned int blk = head->lh_blkno;
    struct gfs2_log_header_host lh;
    int error;

    for (;;) {
        if (++blk == jd->jd_blocks)
            blk = 0;

        error = get_log_header(jd, blk, &lh);
        if (error < 0)
            return error;
        if (error == 1)
            continue;

        if (lh.lh_sequence == head->lh_sequence) {
            gfs2_consist_inode(GFS2_I(jd->jd_inode));
            return -EIO;
        }
        if (lh.lh_sequence < head->lh_sequence)
            break;

        *head = lh;
    }

    return 0;
}

int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
    struct gfs2_log_header_host lh_1, lh_m;
    u32 blk_1, blk_2, blk_m;
    int error;

    blk_1 = 0;
    blk_2 = jd->jd_blocks - 1;

    for (;;) {
        blk_m = (blk_1 + blk_2) / 2;

        error = find_good_lh(jd, &blk_1, &lh_1);
        if (error)
            return error;

        error = find_good_lh(jd, &blk_m, &lh_m);
        if (error)
            return error;

        if (blk_1 == blk_m || blk_m == blk_2)
            break;

        if (lh_1.lh_sequence <= lh_m.lh_sequence)
            blk_1 = blk_m;
        else
            blk_2 = blk_m;
    }

    error = jhead_scan(jd, &lh_1);
    if (error)
        return error;

    *head = lh_1;

    return error;
}

static int foreach_descriptor(struct gfs2_jdesc *jd, unsigned int start,
                  unsigned int end, int pass)
{
    struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
    struct buffer_head *bh;
    struct gfs2_log_descriptor *ld;
    int error = 0;
    u32 length;
    __be64 *ptr;
    unsigned int offset = sizeof(struct gfs2_log_descriptor);
    offset += sizeof(__be64) - 1;
    offset &= ~(sizeof(__be64) - 1);

    while (start != end) {
        error = gfs2_replay_read_block(jd, start, &bh);
        if (error)
            return error;
        if (gfs2_meta_check(sdp, bh)) {
            brelse(bh);
            return -EIO;
        }
        ld = (struct gfs2_log_descriptor *)bh->b_data;
        length = be32_to_cpu(ld->ld_length);

        if (be32_to_cpu(ld->ld_header.mh_type) == GFS2_METATYPE_LH) {
            struct gfs2_log_header_host lh;
            error = get_log_header(jd, start, &lh);
            if (!error) {
                gfs2_replay_incr_blk(sdp, &start);
                brelse(bh);
                continue;
            }
            if (error == 1) {
                gfs2_consist_inode(GFS2_I(jd->jd_inode));
                error = -EIO;
            }
            brelse(bh);
            return error;
        } else if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LD)) {
            brelse(bh);
            return -EIO;
        }
        ptr = (__be64 *)(bh->b_data + offset);
        error = lops_scan_elements(jd, start, ld, ptr, pass);
        if (error) {
            brelse(bh);
            return error;
        }

        while (length--)
            gfs2_replay_incr_blk(sdp, &start);

        brelse(bh);
    }

    return 0;
}

static int clean_journal(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
    struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
    struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
    unsigned int lblock;
    struct gfs2_log_header *lh;
    u32 hash;
    struct buffer_head *bh;
    int error;
    struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };

    lblock = head->lh_blkno;
    gfs2_replay_incr_blk(sdp, &lblock);
    bh_map.b_size = 1 << ip->i_inode.i_blkbits;
    error = gfs2_block_map(&ip->i_inode, lblock, &bh_map, 0);
    if (error)
        return error;
    if (!bh_map.b_blocknr) {
        gfs2_consist_inode(ip);
        return -EIO;
    }

    bh = sb_getblk(sdp->sd_vfs, bh_map.b_blocknr);
    lock_buffer(bh);
    memset(bh->b_data, 0, bh->b_size);
    set_buffer_uptodate(bh);
    clear_buffer_dirty(bh);
    unlock_buffer(bh);

    lh = (struct gfs2_log_header *)bh->b_data;
    memset(lh, 0, sizeof(struct gfs2_log_header));
    lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
    lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
    lh->lh_header.__pad0 = cpu_to_be64(0);
    lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
    lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
    lh->lh_sequence = cpu_to_be64(head->lh_sequence + 1);
    lh->lh_flags = cpu_to_be32(GFS2_LOG_HEAD_UNMOUNT);
    lh->lh_blkno = cpu_to_be32(lblock);
    hash = gfs2_disk_hash((const char *)lh, sizeof(struct gfs2_log_header));
    lh->lh_hash = cpu_to_be32(hash);

    set_buffer_dirty(bh);
    if (sync_dirty_buffer(bh))
        gfs2_io_error_bh(sdp, bh);
    brelse(bh);

    return error;
}


static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
                               unsigned int message)
{
    char env_jid[20];
    char env_status[20];
    char *envp[] = { env_jid, env_status, NULL };
    struct lm_lockstruct *ls = &sdp->sd_lockstruct;

        ls->ls_recover_jid_done = jid;
        ls->ls_recover_jid_status = message;
    sprintf(env_jid, "JID=%d", jid);
    sprintf(env_status, "RECOVERY=%s",
        message == LM_RD_SUCCESS ? "Done" : "Failed");
        kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);

    if (sdp->sd_lockstruct.ls_ops->lm_recovery_result)
        sdp->sd_lockstruct.ls_ops->lm_recovery_result(sdp, jid, message);
}

void gfs2_recover_func(struct work_struct *work)
{
    struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
    struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
    struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
    struct gfs2_log_header_host head;
    struct gfs2_holder j_gh, ji_gh, t_gh;
    unsigned long t;
    int ro = 0;
    unsigned int pass;
    int error;
    int jlocked = 0;

    if (sdp->sd_args.ar_spectator ||
        (jd->jd_jid != sdp->sd_lockstruct.ls_jid)) {
        fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
            jd->jd_jid);
        jlocked = 1;
        /* Acquire the journal lock so we can do recovery */

        error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
                      LM_ST_EXCLUSIVE,
                      LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
                      &j_gh);
        switch (error) {
        case 0:
            break;

        case GLR_TRYFAILED:
            fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
            error = 0;

        default:
            goto fail;
        };

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
                       LM_FLAG_NOEXP | GL_NOCACHE, &ji_gh);
        if (error)
            goto fail_gunlock_j;
    } else {
        fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
    }

    fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);

    error = gfs2_jdesc_check(jd);
    if (error)
        goto fail_gunlock_ji;

    error = gfs2_find_jhead(jd, &head);
    if (error)
        goto fail_gunlock_ji;

    if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
        fs_info(sdp, "jid=%u: Acquiring the transaction lock...\n",
            jd->jd_jid);

        t = jiffies;

        /* Acquire a shared hold on the transaction lock */

        error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED,
                       LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
                       GL_NOCACHE, &t_gh);
        if (error)
            goto fail_gunlock_ji;

        if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
            ro = 1;
        } else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
            if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
                ro = 1;
        } else {
            if (sdp->sd_vfs->s_flags & MS_RDONLY) {
                /* check if device itself is read-only */
                ro = bdev_read_only(sdp->sd_vfs->s_bdev);
                if (!ro) {
                    fs_info(sdp, "recovery required on "
                        "read-only filesystem.\n");
                    fs_info(sdp, "write access will be "
                        "enabled during recovery.\n");
                }
            }
        }

        if (ro) {
            fs_warn(sdp, "jid=%u: Can't replay: read-only block "
                "device\n", jd->jd_jid);
            error = -EROFS;
            goto fail_gunlock_tr;
        }

        fs_info(sdp, "jid=%u: Replaying journal...\n", jd->jd_jid);

        for (pass = 0; pass < 2; pass++) {
            lops_before_scan(jd, &head, pass);
            error = foreach_descriptor(jd, head.lh_tail,
                           head.lh_blkno, pass);
            lops_after_scan(jd, error, pass);
            if (error)
                goto fail_gunlock_tr;
        }

        error = clean_journal(jd, &head);
        if (error)
            goto fail_gunlock_tr;

        gfs2_glock_dq_uninit(&t_gh);
        t = DIV_ROUND_UP(jiffies - t, HZ);
        fs_info(sdp, "jid=%u: Journal replayed in %lus\n",
            jd->jd_jid, t);
    }

    gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);

    if (jlocked) {
        gfs2_glock_dq_uninit(&ji_gh);
        gfs2_glock_dq_uninit(&j_gh);
    }

    fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
    goto done;

fail_gunlock_tr:
    gfs2_glock_dq_uninit(&t_gh);
fail_gunlock_ji:
    if (jlocked) {
        gfs2_glock_dq_uninit(&ji_gh);
fail_gunlock_j:
        gfs2_glock_dq_uninit(&j_gh);
    }

    fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
fail:
    jd->jd_recover_error = error;
    gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
done:
    clear_bit(JDF_RECOVERY, &jd->jd_flags);
    smp_mb__after_clear_bit();
    wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
}

static int gfs2_recovery_wait(void *word)
{
    schedule();
    return 0;
}

int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
{
    int rv;

    if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
        return -EBUSY;

    /* we have JDF_RECOVERY, queue should always succeed */
    rv = queue_work(gfs_recovery_wq, &jd->jd_work);
    BUG_ON(!rv);

    if (wait)
        wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait,
                TASK_UNINTERRUPTIBLE);

    return wait ? jd->jd_recover_error : 0;
}