Merge branch 'master'

[mirror_ubuntu-bionic-kernel.git] / fs / gfs2 / log.c

/*
 * 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 v.2.
 */

#include <linux/sched.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 "lm_interface.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "util.h"
#include "dir.h"

#define PULL 1

/**
 * gfs2_struct2blk - compute stuff
 * @sdp: the filesystem
 * @nstruct: the number of structures
 * @ssize: the size of the structures
 *
 * Compute the number of log descriptor blocks needed to hold a certain number
 * of structures of a certain size.
 *
 * Returns: the number of blocks needed (minimum is always 1)
 */

unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct,
                             unsigned int ssize)
{
        unsigned int blks;
        unsigned int first, second;

        blks = 1;
        first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) /
                ssize;

        if (nstruct > first) {
                second = (sdp->sd_sb.sb_bsize -
                          sizeof(struct gfs2_meta_header)) / ssize;
                blks += DIV_ROUND_UP(nstruct - first, second);
        }

        return blks;
}

void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
{
        struct list_head *head = &sdp->sd_ail1_list;
        uint64_t sync_gen;
        struct list_head *first, *tmp;
        struct gfs2_ail *first_ai, *ai;

        gfs2_log_lock(sdp);
        if (list_empty(head)) {
                gfs2_log_unlock(sdp);
                return;
        }
        sync_gen = sdp->sd_ail_sync_gen++;

        first = head->prev;
        first_ai = list_entry(first, struct gfs2_ail, ai_list);
        first_ai->ai_sync_gen = sync_gen;
        gfs2_ail1_start_one(sdp, first_ai);

        if (flags & DIO_ALL)
                first = NULL;

        for (;;) {
                if (first && (head->prev != first ||
                              gfs2_ail1_empty_one(sdp, first_ai, 0)))
                        break;

                for (tmp = head->prev; tmp != head; tmp = tmp->prev) {
                        ai = list_entry(tmp, struct gfs2_ail, ai_list);
                        if (ai->ai_sync_gen >= sync_gen)
                                continue;
                        ai->ai_sync_gen = sync_gen;
                        gfs2_ail1_start_one(sdp, ai);
                        break;
                }

                if (tmp == head)
                        break;
        }

        gfs2_log_unlock(sdp);
}

int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
{
        struct gfs2_ail *ai, *s;
        int ret;

        gfs2_log_lock(sdp);

        list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
                if (gfs2_ail1_empty_one(sdp, ai, flags))
                        list_move(&ai->ai_list, &sdp->sd_ail2_list);
                else if (!(flags & DIO_ALL))
                        break;
        }

        ret = list_empty(&sdp->sd_ail1_list);

        gfs2_log_unlock(sdp);

        return ret;
}

static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
{
        struct gfs2_ail *ai, *safe;
        unsigned int old_tail = sdp->sd_log_tail;
        int wrap = (new_tail < old_tail);
        int a, b, rm;

        gfs2_log_lock(sdp);

        list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
                a = (old_tail <= ai->ai_first);
                b = (ai->ai_first < new_tail);
                rm = (wrap) ? (a || b) : (a && b);
                if (!rm)
                        continue;

                gfs2_ail2_empty_one(sdp, ai);
                list_del(&ai->ai_list);
                gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
                gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
                kfree(ai);
        }

        gfs2_log_unlock(sdp);
}

/**
 * gfs2_log_reserve - Make a log reservation
 * @sdp: The GFS2 superblock
 * @blks: The number of blocks to reserve
 *
 * Returns: errno
 */

int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
{
        unsigned int try = 0;

        if (gfs2_assert_warn(sdp, blks) ||
            gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
                return -EINVAL;

        mutex_lock(&sdp->sd_log_reserve_mutex);
        gfs2_log_lock(sdp);
        while(sdp->sd_log_blks_free <= blks) {
                gfs2_log_unlock(sdp);
                gfs2_ail1_empty(sdp, 0);
                gfs2_log_flush(sdp, NULL);

                if (try++)
                        gfs2_ail1_start(sdp, 0);
                gfs2_log_lock(sdp);
        }
        sdp->sd_log_blks_free -= blks;
        /* printk(KERN_INFO "reserved %u blocks (%u left)\n", blks, sdp->sd_log_blks_free); */
        gfs2_log_unlock(sdp);
        mutex_unlock(&sdp->sd_log_reserve_mutex);

        down_read(&sdp->sd_log_flush_lock);

        return 0;
}

/**
 * gfs2_log_release - Release a given number of log blocks
 * @sdp: The GFS2 superblock
 * @blks: The number of blocks
 *
 */

void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
{

        gfs2_log_lock(sdp);
        sdp->sd_log_blks_free += blks;
        /* printk(KERN_INFO "released %u blocks (%u left)\n", blks, sdp->sd_log_blks_free); */
        gfs2_assert_withdraw(sdp,
                             sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
        gfs2_log_unlock(sdp);
        up_read(&sdp->sd_log_flush_lock);
}

static uint64_t log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
{
        int new = 0;
        uint64_t dbn;
        int error;
        int bdy;

        error = gfs2_block_map(sdp->sd_jdesc->jd_inode, lbn, &new, &dbn, &bdy);
        gfs2_assert_withdraw(sdp, !error && dbn);

        return dbn;
}

/**
 * log_distance - Compute distance between two journal blocks
 * @sdp: The GFS2 superblock
 * @newer: The most recent journal block of the pair
 * @older: The older journal block of the pair
 *
 *   Compute the distance (in the journal direction) between two
 *   blocks in the journal
 *
 * Returns: the distance in blocks
 */

static inline unsigned int log_distance(struct gfs2_sbd *sdp,
                                        unsigned int newer,
                                        unsigned int older)
{
        int dist;

        dist = newer - older;
        if (dist < 0)
                dist += sdp->sd_jdesc->jd_blocks;

        return dist;
}

static unsigned int current_tail(struct gfs2_sbd *sdp)
{
        struct gfs2_ail *ai;
        unsigned int tail;

        gfs2_log_lock(sdp);

        if (list_empty(&sdp->sd_ail1_list))
                tail = sdp->sd_log_head;
        else {
                ai = list_entry(sdp->sd_ail1_list.prev,
                                struct gfs2_ail, ai_list);
                tail = ai->ai_first;
        }

        gfs2_log_unlock(sdp);

        return tail;
}

static inline void log_incr_head(struct gfs2_sbd *sdp)
{
        if (sdp->sd_log_flush_head == sdp->sd_log_tail)
                gfs2_assert_withdraw(sdp,
                                sdp->sd_log_flush_head == sdp->sd_log_head);

        if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
                sdp->sd_log_flush_head = 0;
                sdp->sd_log_flush_wrapped = 1;
        }
}

/**
 * gfs2_log_get_buf - Get and initialize a buffer to use for log control data
 * @sdp: The GFS2 superblock
 *
 * Returns: the buffer_head
 */

struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
{
        uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
        struct gfs2_log_buf *lb;
        struct buffer_head *bh;

        lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
        list_add(&lb->lb_list, &sdp->sd_log_flush_list);

        bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
        lock_buffer(bh);
        memset(bh->b_data, 0, bh->b_size);
        set_buffer_uptodate(bh);
        clear_buffer_dirty(bh);
        unlock_buffer(bh);

        log_incr_head(sdp);

        return bh;
}

/**
 * gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
 * @sdp: the filesystem
 * @data: the data the buffer_head should point to
 *
 * Returns: the log buffer descriptor
 */

struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
                                      struct buffer_head *real)
{
        uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
        struct gfs2_log_buf *lb;
        struct buffer_head *bh;

        lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
        list_add(&lb->lb_list, &sdp->sd_log_flush_list);
        lb->lb_real = real;

        bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
        atomic_set(&bh->b_count, 1);
        bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
        set_bh_page(bh, real->b_page, bh_offset(real));
        bh->b_blocknr = blkno;
        bh->b_size = sdp->sd_sb.sb_bsize;
        bh->b_bdev = sdp->sd_vfs->s_bdev;

        log_incr_head(sdp);

        return bh;
}

static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
{
        unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);

        ail2_empty(sdp, new_tail);

        gfs2_log_lock(sdp);
        sdp->sd_log_blks_free += dist - ((pull) ? 1 : 0);
        /* printk(KERN_INFO "pull tail refunding %u blocks (%u left) pull=%d\n", dist - ((pull) ? 1 : 0), sdp->sd_log_blks_free, pull); */
        gfs2_assert_withdraw(sdp,
                             sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
        gfs2_log_unlock(sdp);

        sdp->sd_log_tail = new_tail;
}

/**
 * log_write_header - Get and initialize a journal header buffer
 * @sdp: The GFS2 superblock
 *
 * Returns: the initialized log buffer descriptor
 */

static void log_write_header(struct gfs2_sbd *sdp, uint32_t flags, int pull)
{
        uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
        struct buffer_head *bh;
        struct gfs2_log_header *lh;
        unsigned int tail;
        uint32_t hash;

        /* printk(KERN_INFO "log write header start (flags=%08x, pull=%d)\n", flags, pull); */

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

        gfs2_ail1_empty(sdp, 0);
        tail = current_tail(sdp);

        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.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
        lh->lh_sequence = be64_to_cpu(sdp->sd_log_sequence++);
        lh->lh_flags = be32_to_cpu(flags);
        lh->lh_tail = be32_to_cpu(tail);
        lh->lh_blkno = be32_to_cpu(sdp->sd_log_flush_head);
        hash = gfs2_disk_hash(bh->b_data, 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);

        if (sdp->sd_log_tail != tail)
                log_pull_tail(sdp, tail, pull);
        else
                gfs2_assert_withdraw(sdp, !pull);

        sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
        log_incr_head(sdp);

        /* printk(KERN_INFO "log write header out\n"); */
}

static void log_flush_commit(struct gfs2_sbd *sdp)
{
        struct list_head *head = &sdp->sd_log_flush_list;
        struct gfs2_log_buf *lb;
        struct buffer_head *bh;
#if 0
        unsigned int d;

        d = log_distance(sdp, sdp->sd_log_flush_head, sdp->sd_log_head);

        gfs2_assert_withdraw(sdp, d + 1 == sdp->sd_log_blks_reserved);
#endif

        while (!list_empty(head)) {
                lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
                list_del(&lb->lb_list);
                bh = lb->lb_bh;

                wait_on_buffer(bh);
                if (!buffer_uptodate(bh))
                        gfs2_io_error_bh(sdp, bh);
                if (lb->lb_real) {
                        while (atomic_read(&bh->b_count) != 1)  /* Grrrr... */
                                schedule();
                        free_buffer_head(bh);
                } else
                        brelse(bh);
                kfree(lb);
        }

        log_write_header(sdp, 0, 0);
}

/**
 * gfs2_log_flush - flush incore transaction(s)
 * @sdp: the filesystem
 * @gl: The glock structure to flush.  If NULL, flush the whole incore log
 *
 */

void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
{
        struct gfs2_ail *ai;

        down_write(&sdp->sd_log_flush_lock);

        if (gl) {
                gfs2_log_lock(sdp);
                if (list_empty(&gl->gl_le.le_list)) {
                        gfs2_log_unlock(sdp);
                        up_write(&sdp->sd_log_flush_lock);
                        return;
                }
                gfs2_log_unlock(sdp);
        }

        ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
        INIT_LIST_HEAD(&ai->ai_ail1_list);
        INIT_LIST_HEAD(&ai->ai_ail2_list);

        gfs2_assert_withdraw(sdp,
                        sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
        gfs2_assert_withdraw(sdp,
                        sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);

        sdp->sd_log_flush_head = sdp->sd_log_head;
        sdp->sd_log_flush_wrapped = 0;
        ai->ai_first = sdp->sd_log_flush_head;

        lops_before_commit(sdp);
        if (!list_empty(&sdp->sd_log_flush_list))
                log_flush_commit(sdp);
        else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
                log_write_header(sdp, 0, PULL);
        lops_after_commit(sdp, ai);
        sdp->sd_log_head = sdp->sd_log_flush_head;

        /* printk(KERN_INFO "sd_log_num_hdrs %u\n", sdp->sd_log_num_hdrs); */
        sdp->sd_log_blks_free -= sdp->sd_log_num_hdrs;

        sdp->sd_log_blks_reserved =
                sdp->sd_log_commited_buf =
                sdp->sd_log_num_hdrs = 
                sdp->sd_log_commited_revoke = 0;

        gfs2_log_lock(sdp);
        if (!list_empty(&ai->ai_ail1_list)) {
                list_add(&ai->ai_list, &sdp->sd_ail1_list);
                ai = NULL;
        }
        gfs2_log_unlock(sdp);

        sdp->sd_vfs->s_dirt = 0;
        up_write(&sdp->sd_log_flush_lock);

        kfree(ai);
}

static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
        unsigned int reserved = 1;
        unsigned int old;

        gfs2_log_lock(sdp);

        sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
        gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
        sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
        gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);

        if (sdp->sd_log_commited_buf)
                reserved += sdp->sd_log_commited_buf;
        if (sdp->sd_log_commited_revoke)
                reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
                                            sizeof(uint64_t));

        old = sdp->sd_log_blks_free;
        sdp->sd_log_blks_free += tr->tr_reserved -
                                 (reserved - sdp->sd_log_blks_reserved);

        gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free >= old);
        gfs2_assert_withdraw(sdp,
                             sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks +
                             sdp->sd_log_num_hdrs);

        sdp->sd_log_blks_reserved = reserved;

        gfs2_log_unlock(sdp);
}

/**
 * gfs2_log_commit - Commit a transaction to the log
 * @sdp: the filesystem
 * @tr: the transaction
 *
 * Returns: errno
 */

void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
        log_refund(sdp, tr);
        lops_incore_commit(sdp, tr);

        sdp->sd_vfs->s_dirt = 1;
        up_read(&sdp->sd_log_flush_lock);

        gfs2_log_lock(sdp);
        if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
                gfs2_log_unlock(sdp);
                gfs2_log_flush(sdp, NULL);
        } else
                gfs2_log_unlock(sdp);
}

/**
 * gfs2_log_shutdown - write a shutdown header into a journal
 * @sdp: the filesystem
 *
 */

void gfs2_log_shutdown(struct gfs2_sbd *sdp)
{
        down_write(&sdp->sd_log_flush_lock);

        gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
        gfs2_assert_withdraw(sdp, !sdp->sd_log_num_hdrs);
        gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));

        sdp->sd_log_flush_head = sdp->sd_log_head;
        sdp->sd_log_flush_wrapped = 0;

        log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);

        /* printk(KERN_INFO "sd_log_blks_free %u, sd_jdesc->jd_blocks %u\n", sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks); */
        gfs2_assert_warn(sdp, sdp->sd_log_blks_free == sdp->sd_jdesc->jd_blocks);
        gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
        gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));

        sdp->sd_log_head = sdp->sd_log_flush_head;
        sdp->sd_log_tail = sdp->sd_log_head;

        up_write(&sdp->sd_log_flush_lock);
}