// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/kallsyms.h>
#include <linux/gfs2_ondisk.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
#include "trace_gfs2.h"

static void gfs2_print_trans(struct gfs2_sbd *sdp, const struct gfs2_trans *tr)
{
        fs_warn(sdp, "Transaction created at: %pSR\n", (void *)tr->tr_ip);
        fs_warn(sdp, "blocks=%u revokes=%u reserved=%u touched=%u\n",
                tr->tr_blocks, tr->tr_revokes, tr->tr_reserved,
                test_bit(TR_TOUCHED, &tr->tr_flags));
        fs_warn(sdp, "Buf %u/%u Databuf %u/%u Revoke %u\n",
                tr->tr_num_buf_new, tr->tr_num_buf_rm,
                tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
                tr->tr_num_revoke);
}

int __gfs2_trans_begin(struct gfs2_trans *tr, struct gfs2_sbd *sdp,
                       unsigned int blocks, unsigned int revokes,
                       unsigned long ip)
{
        unsigned int extra_revokes;

        if (current->journal_info) {
                gfs2_print_trans(sdp, current->journal_info);
                BUG();
        }
        BUG_ON(blocks == 0 && revokes == 0);

        if (gfs2_withdrawn(sdp))
                return -EROFS;

        tr->tr_ip = ip;
        tr->tr_blocks = blocks;
        tr->tr_revokes = revokes;
        tr->tr_reserved = GFS2_LOG_FLUSH_MIN_BLOCKS;
        if (blocks) {
                /*
                 * The reserved blocks are either used for data or metadata.
                 * We can have mixed data and metadata, each with its own log
                 * descriptor block; see calc_reserved().
                 */
                tr->tr_reserved += blocks + 1 + DIV_ROUND_UP(blocks - 1, databuf_limit(sdp));
        }
        INIT_LIST_HEAD(&tr->tr_databuf);
        INIT_LIST_HEAD(&tr->tr_buf);
        INIT_LIST_HEAD(&tr->tr_list);
        INIT_LIST_HEAD(&tr->tr_ail1_list);
        INIT_LIST_HEAD(&tr->tr_ail2_list);

        if (gfs2_assert_warn(sdp, tr->tr_reserved <= sdp->sd_jdesc->jd_blocks))
                return -EINVAL;

        sb_start_intwrite(sdp->sd_vfs);

        /*
         * Try the reservations under sd_log_flush_lock to prevent log flushes
         * from creating inconsistencies between the number of allocated and
         * reserved revokes.  If that fails, do a full-block allocation outside
         * of the lock to avoid stalling log flushes.  Then, allot the
         * appropriate number of blocks to revokes, use as many revokes locally
         * as needed, and "release" the surplus into the revokes pool.
         */

        down_read(&sdp->sd_log_flush_lock);
        if (unlikely(!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)))
                goto out_not_live;
        if (gfs2_log_try_reserve(sdp, tr, &extra_revokes))
                goto reserved;

        up_read(&sdp->sd_log_flush_lock);
        gfs2_log_reserve(sdp, tr, &extra_revokes);
        down_read(&sdp->sd_log_flush_lock);
        if (unlikely(!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))) {
                revokes = tr->tr_revokes + extra_revokes;
                gfs2_log_release_revokes(sdp, revokes);
                gfs2_log_release(sdp, tr->tr_reserved);
                goto out_not_live;
        }

reserved:
        gfs2_log_release_revokes(sdp, extra_revokes);
        current->journal_info = tr;
        return 0;

out_not_live:
        up_read(&sdp->sd_log_flush_lock);
        sb_end_intwrite(sdp->sd_vfs);
        return -EROFS;
}

int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
                     unsigned int revokes)
{
        struct gfs2_trans *tr;
        int error;

        tr = kmem_cache_zalloc(gfs2_trans_cachep, GFP_NOFS);
        if (!tr)
                return -ENOMEM;
        error = __gfs2_trans_begin(tr, sdp, blocks, revokes, _RET_IP_);
        if (error)
                kmem_cache_free(gfs2_trans_cachep, tr);
        return error;
}

void gfs2_trans_end(struct gfs2_sbd *sdp)
{
        struct gfs2_trans *tr = current->journal_info;
        s64 nbuf;

        current->journal_info = NULL;

        if (!test_bit(TR_TOUCHED, &tr->tr_flags)) {
                gfs2_log_release_revokes(sdp, tr->tr_revokes);
                up_read(&sdp->sd_log_flush_lock);
                gfs2_log_release(sdp, tr->tr_reserved);
                if (!test_bit(TR_ONSTACK, &tr->tr_flags))
                        gfs2_trans_free(sdp, tr);
                sb_end_intwrite(sdp->sd_vfs);
                return;
        }

        gfs2_log_release_revokes(sdp, tr->tr_revokes - tr->tr_num_revoke);

        nbuf = tr->tr_num_buf_new + tr->tr_num_databuf_new;
        nbuf -= tr->tr_num_buf_rm;
        nbuf -= tr->tr_num_databuf_rm;

        if (gfs2_assert_withdraw(sdp, nbuf <= tr->tr_blocks) ||
            gfs2_assert_withdraw(sdp, tr->tr_num_revoke <= tr->tr_revokes))
                gfs2_print_trans(sdp, tr);

        gfs2_log_commit(sdp, tr);
        if (!test_bit(TR_ONSTACK, &tr->tr_flags) &&
            !test_bit(TR_ATTACHED, &tr->tr_flags))
                gfs2_trans_free(sdp, tr);
        up_read(&sdp->sd_log_flush_lock);

        if (sdp->sd_vfs->s_flags & SB_SYNCHRONOUS)
                gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
                               GFS2_LFC_TRANS_END);
        sb_end_intwrite(sdp->sd_vfs);
}

static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl,
                                               struct buffer_head *bh)
{
        struct gfs2_bufdata *bd;

        bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
        bd->bd_bh = bh;
        bd->bd_gl = gl;
        INIT_LIST_HEAD(&bd->bd_list);
        INIT_LIST_HEAD(&bd->bd_ail_st_list);
        INIT_LIST_HEAD(&bd->bd_ail_gl_list);
        bh->b_private = bd;
        return bd;
}

/**
 * gfs2_trans_add_data - Add a databuf to the transaction.
 * @gl: The inode glock associated with the buffer
 * @bh: The buffer to add
 *
 * This is used in journaled data mode.
 * We need to journal the data block in the same way as metadata in
 * the functions above. The difference is that here we have a tag
 * which is two __be64's being the block number (as per meta data)
 * and a flag which says whether the data block needs escaping or
 * not. This means we need a new log entry for each 251 or so data
 * blocks, which isn't an enormous overhead but twice as much as
 * for normal metadata blocks.
 */
void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
{
        struct gfs2_trans *tr = current->journal_info;
        struct gfs2_sbd *sdp = glock_sbd(gl);
        struct gfs2_bufdata *bd;

        lock_buffer(bh);
        if (buffer_pinned(bh)) {
                set_bit(TR_TOUCHED, &tr->tr_flags);
                goto out;
        }
        gfs2_log_lock(sdp);
        bd = bh->b_private;
        if (bd == NULL) {
                gfs2_log_unlock(sdp);
                unlock_buffer(bh);
                if (bh->b_private == NULL)
                        bd = gfs2_alloc_bufdata(gl, bh);
                else
                        bd = bh->b_private;
                lock_buffer(bh);
                gfs2_log_lock(sdp);
        }
        gfs2_assert(sdp, bd->bd_gl == gl);
        set_bit(TR_TOUCHED, &tr->tr_flags);
        if (list_empty(&bd->bd_list)) {
                set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
                set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
                gfs2_pin(sdp, bd->bd_bh);
                tr->tr_num_databuf_new++;
                list_add_tail(&bd->bd_list, &tr->tr_databuf);
        }
        gfs2_log_unlock(sdp);
out:
        unlock_buffer(bh);
}

void gfs2_trans_add_databufs(struct gfs2_glock *gl, struct folio *folio,
                             size_t from, size_t len)
{
        struct buffer_head *head = folio_buffers(folio);
        unsigned int bsize = head->b_size;
        struct buffer_head *bh;
        size_t to = from + len;
        size_t start, end;

        for (bh = head, start = 0; bh != head || !start;
             bh = bh->b_this_page, start = end) {
                end = start + bsize;
                if (end <= from)
                        continue;
                if (start >= to)
                        break;
                set_buffer_uptodate(bh);
                gfs2_trans_add_data(gl, bh);
        }
}

void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh)
{

        struct gfs2_sbd *sdp = glock_sbd(gl);
        struct super_block *sb = sdp->sd_vfs;
        struct gfs2_bufdata *bd;
        struct gfs2_meta_header *mh;
        struct gfs2_trans *tr = current->journal_info;

        lock_buffer(bh);
        if (buffer_pinned(bh)) {
                set_bit(TR_TOUCHED, &tr->tr_flags);
                goto out;
        }
        gfs2_log_lock(sdp);
        bd = bh->b_private;
        if (bd == NULL) {
                gfs2_log_unlock(sdp);
                unlock_buffer(bh);
                folio_lock(bh->b_folio);
                if (bh->b_private == NULL)
                        bd = gfs2_alloc_bufdata(gl, bh);
                else
                        bd = bh->b_private;
                folio_unlock(bh->b_folio);
                lock_buffer(bh);
                gfs2_log_lock(sdp);
        }
        gfs2_assert(sdp, bd->bd_gl == gl);
        set_bit(TR_TOUCHED, &tr->tr_flags);
        if (!list_empty(&bd->bd_list))
                goto out_unlock;
        set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
        set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
        mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
        if (unlikely(mh->mh_magic != cpu_to_be32(GFS2_MAGIC))) {
                fs_err(sdp, "Attempting to add uninitialised block to "
                       "journal (inplace block=%lld)\n",
                       (unsigned long long)bd->bd_bh->b_blocknr);
                BUG();
        }
        if (gfs2_withdrawn(sdp)) {
                fs_info(sdp, "GFS2:adding buf while withdrawn! 0x%llx\n",
                        (unsigned long long)bd->bd_bh->b_blocknr);
                goto out_unlock;
        }
        if (unlikely(sb->s_writers.frozen == SB_FREEZE_COMPLETE)) {
                fs_info(sdp, "GFS2:adding buf while frozen\n");
                gfs2_withdraw(sdp);
                goto out_unlock;
        }
        gfs2_pin(sdp, bd->bd_bh);
        mh->__pad0 = cpu_to_be64(0);
        mh->mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
        list_add(&bd->bd_list, &tr->tr_buf);
        tr->tr_num_buf_new++;
out_unlock:
        gfs2_log_unlock(sdp);
out:
        unlock_buffer(bh);
}

void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
        struct gfs2_trans *tr = current->journal_info;

        BUG_ON(!list_empty(&bd->bd_list));
        gfs2_add_revoke(sdp, bd);
        set_bit(TR_TOUCHED, &tr->tr_flags);
        tr->tr_num_revoke++;
}

void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
{
        struct gfs2_bufdata *bd, *tmp;
        unsigned int n = len;

        gfs2_log_lock(sdp);
        list_for_each_entry_safe(bd, tmp, &sdp->sd_log_revokes, bd_list) {
                if ((bd->bd_blkno >= blkno) && (bd->bd_blkno < (blkno + len))) {
                        list_del_init(&bd->bd_list);
                        gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
                        sdp->sd_log_num_revoke--;
                        if (bd->bd_gl)
                                gfs2_glock_remove_revoke(bd->bd_gl);
                        kmem_cache_free(gfs2_bufdata_cachep, bd);
                        gfs2_log_release_revokes(sdp, 1);
                        if (--n == 0)
                                break;
                }
        }
        gfs2_log_unlock(sdp);
}

void gfs2_trans_free(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
        if (tr == NULL)
                return;

        gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));
        gfs2_assert_warn(sdp, list_empty(&tr->tr_ail2_list));
        gfs2_assert_warn(sdp, list_empty(&tr->tr_databuf));
        gfs2_assert_warn(sdp, list_empty(&tr->tr_buf));
        kmem_cache_free(gfs2_trans_cachep, tr);
}