/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2008 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/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/bio.h>
#include <linux/posix_acl.h>
#include <linux/security.h>

#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "meta_io.h"
#include "recovery.h"
#include "rgrp.h"
#include "util.h"
#include "trans.h"
#include "dir.h"

struct workqueue_struct *gfs2_freeze_wq;

static void gfs2_ail_error(struct gfs2_glock *gl, const struct buffer_head *bh)
{
        fs_err(gl->gl_name.ln_sbd,
               "AIL buffer %p: blocknr %llu state 0x%08lx mapping %p page "
               "state 0x%lx\n",
               bh, (unsigned long long)bh->b_blocknr, bh->b_state,
               bh->b_page->mapping, bh->b_page->flags);
        fs_err(gl->gl_name.ln_sbd, "AIL glock %u:%llu mapping %p\n",
               gl->gl_name.ln_type, gl->gl_name.ln_number,
               gfs2_glock2aspace(gl));
        gfs2_lm_withdraw(gl->gl_name.ln_sbd, "AIL error\n");
}

/**
 * __gfs2_ail_flush - remove all buffers for a given lock from the AIL
 * @gl: the glock
 * @fsync: set when called from fsync (not all buffers will be clean)
 *
 * None of the buffers should be dirty, locked, or pinned.
 */

static void __gfs2_ail_flush(struct gfs2_glock *gl, bool fsync,
                             unsigned int nr_revokes)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct list_head *head = &gl->gl_ail_list;
        struct gfs2_bufdata *bd, *tmp;
        struct buffer_head *bh;
        const unsigned long b_state = (1UL << BH_Dirty)|(1UL << BH_Pinned)|(1UL << BH_Lock);

        gfs2_log_lock(sdp);
        spin_lock(&sdp->sd_ail_lock);
        list_for_each_entry_safe_reverse(bd, tmp, head, bd_ail_gl_list) {
                if (nr_revokes == 0)
                        break;
                bh = bd->bd_bh;
                if (bh->b_state & b_state) {
                        if (fsync)
                                continue;
                        gfs2_ail_error(gl, bh);
                }
                gfs2_trans_add_revoke(sdp, bd);
                nr_revokes--;
        }
        GLOCK_BUG_ON(gl, !fsync && atomic_read(&gl->gl_ail_count));
        spin_unlock(&sdp->sd_ail_lock);
        gfs2_log_unlock(sdp);
}


static void gfs2_ail_empty_gl(struct gfs2_glock *gl)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct gfs2_trans tr;

        memset(&tr, 0, sizeof(tr));
        INIT_LIST_HEAD(&tr.tr_buf);
        INIT_LIST_HEAD(&tr.tr_databuf);
        tr.tr_revokes = atomic_read(&gl->gl_ail_count);

        if (!tr.tr_revokes)
                return;

        /* A shortened, inline version of gfs2_trans_begin()
         * tr->alloced is not set since the transaction structure is
         * on the stack */
        tr.tr_reserved = 1 + gfs2_struct2blk(sdp, tr.tr_revokes, sizeof(u64));
        tr.tr_ip = _RET_IP_;
        if (gfs2_log_reserve(sdp, tr.tr_reserved) < 0)
                return;
        WARN_ON_ONCE(current->journal_info);
        current->journal_info = &tr;

        __gfs2_ail_flush(gl, 0, tr.tr_revokes);

        gfs2_trans_end(sdp);
        gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
}

void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        unsigned int revokes = atomic_read(&gl->gl_ail_count);
        unsigned int max_revokes = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) / sizeof(u64);
        int ret;

        if (!revokes)
                return;

        while (revokes > max_revokes)
                max_revokes += (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header)) / sizeof(u64);

        ret = gfs2_trans_begin(sdp, 0, max_revokes);
        if (ret)
                return;
        __gfs2_ail_flush(gl, fsync, max_revokes);
        gfs2_trans_end(sdp);
        gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
}

/**
 * rgrp_go_sync - sync out the metadata for this glock
 * @gl: the glock
 *
 * Called when demoting or unlocking an EX glock.  We must flush
 * to disk all dirty buffers/pages relating to this glock, and must not
 * return to caller to demote/unlock the glock until I/O is complete.
 */

static void rgrp_go_sync(struct gfs2_glock *gl)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct address_space *mapping = &sdp->sd_aspace;
        struct gfs2_rgrpd *rgd;
        int error;

        spin_lock(&gl->gl_lockref.lock);
        rgd = gl->gl_object;
        if (rgd)
                gfs2_rgrp_brelse(rgd);
        spin_unlock(&gl->gl_lockref.lock);

        if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
                return;
        GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);

        gfs2_log_flush(sdp, gl, NORMAL_FLUSH);
        filemap_fdatawrite_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
        error = filemap_fdatawait_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
        mapping_set_error(mapping, error);
        gfs2_ail_empty_gl(gl);

        spin_lock(&gl->gl_lockref.lock);
        rgd = gl->gl_object;
        if (rgd)
                gfs2_free_clones(rgd);
        spin_unlock(&gl->gl_lockref.lock);
}

/**
 * rgrp_go_inval - invalidate the metadata for this glock
 * @gl: the glock
 * @flags:
 *
 * We never used LM_ST_DEFERRED with resource groups, so that we
 * should always see the metadata flag set here.
 *
 */

static void rgrp_go_inval(struct gfs2_glock *gl, int flags)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct address_space *mapping = &sdp->sd_aspace;
        struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl);

        if (rgd)
                gfs2_rgrp_brelse(rgd);

        WARN_ON_ONCE(!(flags & DIO_METADATA));
        gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
        truncate_inode_pages_range(mapping, gl->gl_vm.start, gl->gl_vm.end);

        if (rgd)
                rgd->rd_flags &= ~GFS2_RDF_UPTODATE;
}

static struct gfs2_inode *gfs2_glock2inode(struct gfs2_glock *gl)
{
        struct gfs2_inode *ip;

        spin_lock(&gl->gl_lockref.lock);
        ip = gl->gl_object;
        if (ip)
                set_bit(GIF_GLOP_PENDING, &ip->i_flags);
        spin_unlock(&gl->gl_lockref.lock);
        return ip;
}

struct gfs2_rgrpd *gfs2_glock2rgrp(struct gfs2_glock *gl)
{
        struct gfs2_rgrpd *rgd;

        spin_lock(&gl->gl_lockref.lock);
        rgd = gl->gl_object;
        spin_unlock(&gl->gl_lockref.lock);

        return rgd;
}

static void gfs2_clear_glop_pending(struct gfs2_inode *ip)
{
        if (!ip)
                return;

        clear_bit_unlock(GIF_GLOP_PENDING, &ip->i_flags);
        wake_up_bit(&ip->i_flags, GIF_GLOP_PENDING);
}

/**
 * inode_go_sync - Sync the dirty data and/or metadata for an inode glock
 * @gl: the glock protecting the inode
 *
 */

static void inode_go_sync(struct gfs2_glock *gl)
{
        struct gfs2_inode *ip = gfs2_glock2inode(gl);
        int isreg = ip && S_ISREG(ip->i_inode.i_mode);
        struct address_space *metamapping = gfs2_glock2aspace(gl);
        int error;

        if (isreg) {
                if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
                        unmap_shared_mapping_range(ip->i_inode.i_mapping, 0, 0);
                inode_dio_wait(&ip->i_inode);
        }
        if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
                goto out;

        GLOCK_BUG_ON(gl, gl->gl_state != LM_ST_EXCLUSIVE);

        gfs2_log_flush(gl->gl_name.ln_sbd, gl, NORMAL_FLUSH);
        filemap_fdatawrite(metamapping);
        if (isreg) {
                struct address_space *mapping = ip->i_inode.i_mapping;
                filemap_fdatawrite(mapping);
                error = filemap_fdatawait(mapping);
                mapping_set_error(mapping, error);
        }
        error = filemap_fdatawait(metamapping);
        mapping_set_error(metamapping, error);
        gfs2_ail_empty_gl(gl);
        /*
         * Writeback of the data mapping may cause the dirty flag to be set
         * so we have to clear it again here.
         */
        smp_mb__before_atomic();
        clear_bit(GLF_DIRTY, &gl->gl_flags);

out:
        gfs2_clear_glop_pending(ip);
}

/**
 * inode_go_inval - prepare a inode glock to be released
 * @gl: the glock
 * @flags:
 *
 * Normally we invalidate everything, but if we are moving into
 * LM_ST_DEFERRED from LM_ST_SHARED or LM_ST_EXCLUSIVE then we
 * can keep hold of the metadata, since it won't have changed.
 *
 */

static void inode_go_inval(struct gfs2_glock *gl, int flags)
{
        struct gfs2_inode *ip = gfs2_glock2inode(gl);

        gfs2_assert_withdraw(gl->gl_name.ln_sbd, !atomic_read(&gl->gl_ail_count));

        if (flags & DIO_METADATA) {
                struct address_space *mapping = gfs2_glock2aspace(gl);
                truncate_inode_pages(mapping, 0);
                if (ip) {
                        set_bit(GIF_INVALID, &ip->i_flags);
                        forget_all_cached_acls(&ip->i_inode);
                        security_inode_invalidate_secctx(&ip->i_inode);
                        gfs2_dir_hash_inval(ip);
                }
        }

        if (ip == GFS2_I(gl->gl_name.ln_sbd->sd_rindex)) {
                gfs2_log_flush(gl->gl_name.ln_sbd, NULL, NORMAL_FLUSH);
                gl->gl_name.ln_sbd->sd_rindex_uptodate = 0;
        }
        if (ip && S_ISREG(ip->i_inode.i_mode))
                truncate_inode_pages(ip->i_inode.i_mapping, 0);

        gfs2_clear_glop_pending(ip);
}

/**
 * inode_go_demote_ok - Check to see if it's ok to unlock an inode glock
 * @gl: the glock
 *
 * Returns: 1 if it's ok
 */

static int inode_go_demote_ok(const struct gfs2_glock *gl)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

        if (sdp->sd_jindex == gl->gl_object || sdp->sd_rindex == gl->gl_object)
                return 0;

        return 1;
}

static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
{
        const struct gfs2_dinode *str = buf;
        struct timespec atime;
        u16 height, depth;

        if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr)))
                goto corrupt;
        ip->i_no_formal_ino = be64_to_cpu(str->di_num.no_formal_ino);
        ip->i_inode.i_mode = be32_to_cpu(str->di_mode);
        ip->i_inode.i_rdev = 0;
        switch (ip->i_inode.i_mode & S_IFMT) {
        case S_IFBLK:
        case S_IFCHR:
                ip->i_inode.i_rdev = MKDEV(be32_to_cpu(str->di_major),
                                           be32_to_cpu(str->di_minor));
                break;
        };

        i_uid_write(&ip->i_inode, be32_to_cpu(str->di_uid));
        i_gid_write(&ip->i_inode, be32_to_cpu(str->di_gid));
        set_nlink(&ip->i_inode, be32_to_cpu(str->di_nlink));
        i_size_write(&ip->i_inode, be64_to_cpu(str->di_size));
        gfs2_set_inode_blocks(&ip->i_inode, be64_to_cpu(str->di_blocks));
        atime.tv_sec = be64_to_cpu(str->di_atime);
        atime.tv_nsec = be32_to_cpu(str->di_atime_nsec);
        if (timespec_compare(&ip->i_inode.i_atime, &atime) < 0)
                ip->i_inode.i_atime = atime;
        ip->i_inode.i_mtime.tv_sec = be64_to_cpu(str->di_mtime);
        ip->i_inode.i_mtime.tv_nsec = be32_to_cpu(str->di_mtime_nsec);
        ip->i_inode.i_ctime.tv_sec = be64_to_cpu(str->di_ctime);
        ip->i_inode.i_ctime.tv_nsec = be32_to_cpu(str->di_ctime_nsec);

        ip->i_goal = be64_to_cpu(str->di_goal_meta);
        ip->i_generation = be64_to_cpu(str->di_generation);

        ip->i_diskflags = be32_to_cpu(str->di_flags);
        ip->i_eattr = be64_to_cpu(str->di_eattr);
        /* i_diskflags and i_eattr must be set before gfs2_set_inode_flags() */
        gfs2_set_inode_flags(&ip->i_inode);
        height = be16_to_cpu(str->di_height);
        if (unlikely(height > GFS2_MAX_META_HEIGHT))
                goto corrupt;
        ip->i_height = (u8)height;

        depth = be16_to_cpu(str->di_depth);
        if (unlikely(depth > GFS2_DIR_MAX_DEPTH))
                goto corrupt;
        ip->i_depth = (u8)depth;
        ip->i_entries = be32_to_cpu(str->di_entries);

        if (S_ISREG(ip->i_inode.i_mode))
                gfs2_set_aops(&ip->i_inode);

        return 0;
corrupt:
        gfs2_consist_inode(ip);
        return -EIO;
}

/**
 * gfs2_inode_refresh - Refresh the incore copy of the dinode
 * @ip: The GFS2 inode
 *
 * Returns: errno
 */

int gfs2_inode_refresh(struct gfs2_inode *ip)
{
        struct buffer_head *dibh;
        int error;

        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (error)
                return error;

        error = gfs2_dinode_in(ip, dibh->b_data);
        brelse(dibh);
        clear_bit(GIF_INVALID, &ip->i_flags);

        return error;
}

/**
 * inode_go_lock - operation done after an inode lock is locked by a process
 * @gl: the glock
 * @flags:
 *
 * Returns: errno
 */

static int inode_go_lock(struct gfs2_holder *gh)
{
        struct gfs2_glock *gl = gh->gh_gl;
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct gfs2_inode *ip = gl->gl_object;
        int error = 0;

        if (!ip || (gh->gh_flags & GL_SKIP))
                return 0;

        if (test_bit(GIF_INVALID, &ip->i_flags)) {
                error = gfs2_inode_refresh(ip);
                if (error)
                        return error;
        }

        if (gh->gh_state != LM_ST_DEFERRED)
                inode_dio_wait(&ip->i_inode);

        if ((ip->i_diskflags & GFS2_DIF_TRUNC_IN_PROG) &&
            (gl->gl_state == LM_ST_EXCLUSIVE) &&
            (gh->gh_state == LM_ST_EXCLUSIVE)) {
                spin_lock(&sdp->sd_trunc_lock);
                if (list_empty(&ip->i_trunc_list))
                        list_add(&ip->i_trunc_list, &sdp->sd_trunc_list);
                spin_unlock(&sdp->sd_trunc_lock);
                wake_up(&sdp->sd_quota_wait);
                return 1;
        }

        return error;
}

/**
 * inode_go_dump - print information about an inode
 * @seq: The iterator
 * @ip: the inode
 *
 */

static void inode_go_dump(struct seq_file *seq, const struct gfs2_glock *gl)
{
        const struct gfs2_inode *ip = gl->gl_object;
        if (ip == NULL)
                return;
        gfs2_print_dbg(seq, " I: n:%llu/%llu t:%u f:0x%02lx d:0x%08x s:%llu\n",
                  (unsigned long long)ip->i_no_formal_ino,
                  (unsigned long long)ip->i_no_addr,
                  IF2DT(ip->i_inode.i_mode), ip->i_flags,
                  (unsigned int)ip->i_diskflags,
                  (unsigned long long)i_size_read(&ip->i_inode));
}

/**
 * freeze_go_sync - promote/demote the freeze glock
 * @gl: the glock
 * @state: the requested state
 * @flags:
 *
 */

static void freeze_go_sync(struct gfs2_glock *gl)
{
        int error = 0;
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

        if (gl->gl_state == LM_ST_SHARED &&
            test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
                atomic_set(&sdp->sd_freeze_state, SFS_STARTING_FREEZE);
                error = freeze_super(sdp->sd_vfs);
                if (error) {
                        printk(KERN_INFO "GFS2: couldn't freeze filesystem: %d\n", error);
                        gfs2_assert_withdraw(sdp, 0);
                }
                queue_work(gfs2_freeze_wq, &sdp->sd_freeze_work);
                gfs2_log_flush(sdp, NULL, FREEZE_FLUSH);
        }
}

/**
 * freeze_go_xmote_bh - After promoting/demoting the freeze glock
 * @gl: the glock
 *
 */

static int freeze_go_xmote_bh(struct gfs2_glock *gl, struct gfs2_holder *gh)
{
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
        struct gfs2_glock *j_gl = ip->i_gl;
        struct gfs2_log_header_host head;
        int error;

        if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
                j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);

                error = gfs2_find_jhead(sdp->sd_jdesc, &head);
                if (error)
                        gfs2_consist(sdp);
                if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT))
                        gfs2_consist(sdp);

                /*  Initialize some head of the log stuff  */
                if (!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) {
                        sdp->sd_log_sequence = head.lh_sequence + 1;
                        gfs2_log_pointers_init(sdp, head.lh_blkno);
                }
        }
        return 0;
}

/**
 * trans_go_demote_ok
 * @gl: the glock
 *
 * Always returns 0
 */

static int freeze_go_demote_ok(const struct gfs2_glock *gl)
{
        return 0;
}

/**
 * iopen_go_callback - schedule the dcache entry for the inode to be deleted
 * @gl: the glock
 *
 * gl_lockref.lock lock is held while calling this
 */
static void iopen_go_callback(struct gfs2_glock *gl, bool remote)
{
        struct gfs2_inode *ip = gl->gl_object;
        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;

        if (!remote || sb_rdonly(sdp->sd_vfs))
                return;

        if (gl->gl_demote_state == LM_ST_UNLOCKED &&
            gl->gl_state == LM_ST_SHARED && ip) {
                gl->gl_lockref.count++;
                if (queue_work(gfs2_delete_workqueue, &gl->gl_delete) == 0)
                        gl->gl_lockref.count--;
        }
}

const struct gfs2_glock_operations gfs2_meta_glops = {
        .go_type = LM_TYPE_META,
};

const struct gfs2_glock_operations gfs2_inode_glops = {
        .go_sync = inode_go_sync,
        .go_inval = inode_go_inval,
        .go_demote_ok = inode_go_demote_ok,
        .go_lock = inode_go_lock,
        .go_dump = inode_go_dump,
        .go_type = LM_TYPE_INODE,
        .go_flags = GLOF_ASPACE | GLOF_LRU,
};

const struct gfs2_glock_operations gfs2_rgrp_glops = {
        .go_sync = rgrp_go_sync,
        .go_inval = rgrp_go_inval,
        .go_lock = gfs2_rgrp_go_lock,
        .go_unlock = gfs2_rgrp_go_unlock,
        .go_dump = gfs2_rgrp_dump,
        .go_type = LM_TYPE_RGRP,
        .go_flags = GLOF_LVB,
};

const struct gfs2_glock_operations gfs2_freeze_glops = {
        .go_sync = freeze_go_sync,
        .go_xmote_bh = freeze_go_xmote_bh,
        .go_demote_ok = freeze_go_demote_ok,
        .go_type = LM_TYPE_NONDISK,
};

const struct gfs2_glock_operations gfs2_iopen_glops = {
        .go_type = LM_TYPE_IOPEN,
        .go_callback = iopen_go_callback,
        .go_flags = GLOF_LRU,
};

const struct gfs2_glock_operations gfs2_flock_glops = {
        .go_type = LM_TYPE_FLOCK,
        .go_flags = GLOF_LRU,
};

const struct gfs2_glock_operations gfs2_nondisk_glops = {
        .go_type = LM_TYPE_NONDISK,
};

const struct gfs2_glock_operations gfs2_quota_glops = {
        .go_type = LM_TYPE_QUOTA,
        .go_flags = GLOF_LVB | GLOF_LRU,
};

const struct gfs2_glock_operations gfs2_journal_glops = {
        .go_type = LM_TYPE_JOURNAL,
};

const struct gfs2_glock_operations *gfs2_glops_list[] = {
        [LM_TYPE_META] = &gfs2_meta_glops,
        [LM_TYPE_INODE] = &gfs2_inode_glops,
        [LM_TYPE_RGRP] = &gfs2_rgrp_glops,
        [LM_TYPE_IOPEN] = &gfs2_iopen_glops,
        [LM_TYPE_FLOCK] = &gfs2_flock_glops,
        [LM_TYPE_NONDISK] = &gfs2_nondisk_glops,
        [LM_TYPE_QUOTA] = &gfs2_quota_glops,
        [LM_TYPE_JOURNAL] = &gfs2_journal_glops,
};