/*
 * 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 "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"

/**
 * __gfs2_ail_flush - remove all buffers for a given lock from the AIL
 * @gl: the glock
 *
 * None of the buffers should be dirty, locked, or pinned.
 */

static void __gfs2_ail_flush(struct gfs2_glock *gl)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct list_head *head = &gl->gl_ail_list;
	struct gfs2_bufdata *bd;
	struct buffer_head *bh;

	spin_lock(&sdp->sd_ail_lock);
	while (!list_empty(head)) {
		bd = list_entry(head->next, struct gfs2_bufdata,
				bd_ail_gl_list);
		bh = bd->bd_bh;
		gfs2_remove_from_ail(bd);
		spin_unlock(&sdp->sd_ail_lock);

		bd->bd_bh = NULL;
		bh->b_private = NULL;
		bd->bd_blkno = bh->b_blocknr;
		gfs2_log_lock(sdp);
		gfs2_assert_withdraw(sdp, !buffer_busy(bh));
		gfs2_trans_add_revoke(sdp, bd);
		gfs2_log_unlock(sdp);

		spin_lock(&sdp->sd_ail_lock);
	}
	gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
	spin_unlock(&sdp->sd_ail_lock);
}


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

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

	if (!tr.tr_revokes)
		return;

	/* A shortened, inline version of gfs2_trans_begin() */
	tr.tr_reserved = 1 + gfs2_struct2blk(sdp, tr.tr_revokes, sizeof(u64));
	tr.tr_ip = (unsigned long)__builtin_return_address(0);
	INIT_LIST_HEAD(&tr.tr_list_buf);
	gfs2_log_reserve(sdp, tr.tr_reserved);
	BUG_ON(current->journal_info);
	current->journal_info = &tr;

	__gfs2_ail_flush(gl);

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

void gfs2_ail_flush(struct gfs2_glock *gl)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	unsigned int revokes = atomic_read(&gl->gl_ail_count);
	int ret;

	if (!revokes)
		return;

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

/**
 * 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
 * not return to caller to demote/unlock the glock until I/O is complete.
 */

static void rgrp_go_sync(struct gfs2_glock *gl)
{
	struct address_space *metamapping = gfs2_glock2aspace(gl);
	int error;

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

	gfs2_log_flush(gl->gl_sbd, gl);
	filemap_fdatawrite(metamapping);
	error = filemap_fdatawait(metamapping);
        mapping_set_error(metamapping, error);
	gfs2_ail_empty_gl(gl);
}

/**
 * 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 address_space *mapping = gfs2_glock2aspace(gl);

	BUG_ON(!(flags & DIO_METADATA));
	gfs2_assert_withdraw(gl->gl_sbd, !atomic_read(&gl->gl_ail_count));
	truncate_inode_pages(mapping, 0);

	if (gl->gl_object) {
		struct gfs2_rgrpd *rgd = (struct gfs2_rgrpd *)gl->gl_object;
		rgd->rd_flags &= ~GFS2_RDF_UPTODATE;
	}
}

/**
 * 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 = gl->gl_object;
	struct address_space *metamapping = gfs2_glock2aspace(gl);
	int error;

	if (ip && !S_ISREG(ip->i_inode.i_mode))
		ip = NULL;
	if (ip && test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
		unmap_shared_mapping_range(ip->i_inode.i_mapping, 0, 0);
	if (!test_and_clear_bit(GLF_DIRTY, &gl->gl_flags))
		return;

	BUG_ON(gl->gl_state != LM_ST_EXCLUSIVE);

	gfs2_log_flush(gl->gl_sbd, gl);
	filemap_fdatawrite(metamapping);
	if (ip) {
		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_clear_bit();
	clear_bit(GLF_DIRTY, &gl->gl_flags);
}

/**
 * inode_go_inval - prepare a inode glock to be released
 * @gl: the glock
 * @flags:
 * 
 * Normally we invlidate 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 = gl->gl_object;

	gfs2_assert_withdraw(gl->gl_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);
		}
	}

	if (ip == GFS2_I(gl->gl_sbd->sd_rindex))
		gl->gl_sbd->sd_rindex_uptodate = 0;
	if (ip && S_ISREG(ip->i_inode.i_mode))
		truncate_inode_pages(ip->i_inode.i_mapping, 0);
}

/**
 * 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_sbd;
	struct gfs2_holder *gh;

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

	if (!list_empty(&gl->gl_holders)) {
		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
		if (gh->gh_list.next != &gl->gl_holders)
			return 0;
	}

	return 1;
}

/**
 * gfs2_set_nlink - Set the inode's link count based on on-disk info
 * @inode: The inode in question
 * @nlink: The link count
 *
 * If the link count has hit zero, it must never be raised, whatever the
 * on-disk inode might say. When new struct inodes are created the link
 * count is set to 1, so that we can safely use this test even when reading
 * in on disk information for the first time.
 */

static void gfs2_set_nlink(struct inode *inode, u32 nlink)
{
	/*
	 * We will need to review setting the nlink count here in the
	 * light of the forthcoming ro bind mount work. This is a reminder
	 * to do that.
	 */
	if ((inode->i_nlink != nlink) && (inode->i_nlink != 0)) {
		if (nlink == 0)
			clear_nlink(inode);
		else
			inode->i_nlink = nlink;
	}
}

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;
	};

	ip->i_inode.i_uid = be32_to_cpu(str->di_uid);
	ip->i_inode.i_gid = be32_to_cpu(str->di_gid);
	gfs2_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);
	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);

	ip->i_eattr = be64_to_cpu(str->di_eattr);
	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;

	if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), dibh, GFS2_METATYPE_DI)) {
		brelse(dibh);
		return -EIO;
	}

	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_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 ((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(&sdp->sd_trunc_list, &ip->i_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
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

static int inode_go_dump(struct seq_file *seq, const struct gfs2_glock *gl)
{
	const struct gfs2_inode *ip = gl->gl_object;
	if (ip == NULL)
		return 0;
	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));
	return 0;
}

/**
 * rgrp_go_lock - operation done after an rgrp lock is locked by
 *    a first holder on this node.
 * @gl: the glock
 * @flags:
 *
 * Returns: errno
 */

static int rgrp_go_lock(struct gfs2_holder *gh)
{
	return gfs2_rgrp_bh_get(gh->gh_gl->gl_object);
}

/**
 * rgrp_go_unlock - operation done before an rgrp lock is unlocked by
 *    a last holder on this node.
 * @gl: the glock
 * @flags:
 *
 */

static void rgrp_go_unlock(struct gfs2_holder *gh)
{
	gfs2_rgrp_bh_put(gh->gh_gl->gl_object);
}

/**
 * trans_go_sync - promote/demote the transaction glock
 * @gl: the glock
 * @state: the requested state
 * @flags:
 *
 */

static void trans_go_sync(struct gfs2_glock *gl)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;

	if (gl->gl_state != LM_ST_UNLOCKED &&
	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
		gfs2_meta_syncfs(sdp);
		gfs2_log_shutdown(sdp);
	}
}

/**
 * trans_go_xmote_bh - After promoting/demoting the transaction glock
 * @gl: the glock
 *
 */

static int trans_go_xmote_bh(struct gfs2_glock *gl, struct gfs2_holder *gh)
{
	struct gfs2_sbd *sdp = gl->gl_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 trans_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_spin lock is held while calling this
 */
static void iopen_go_callback(struct gfs2_glock *gl)
{
	struct gfs2_inode *ip = (struct gfs2_inode *)gl->gl_object;
	struct gfs2_sbd *sdp = gl->gl_sbd;

	if (sdp->sd_vfs->s_flags & MS_RDONLY)
		return;

	if (gl->gl_demote_state == LM_ST_UNLOCKED &&
	    gl->gl_state == LM_ST_SHARED && ip) {
		gfs2_glock_hold(gl);
		if (queue_work(gfs2_delete_workqueue, &gl->gl_delete) == 0)
			gfs2_glock_put_nolock(gl);
	}
}

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

const struct gfs2_glock_operations gfs2_inode_glops = {
	.go_xmote_th = 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_min_hold_time = HZ / 5,
	.go_flags = GLOF_ASPACE,
};

const struct gfs2_glock_operations gfs2_rgrp_glops = {
	.go_xmote_th = rgrp_go_sync,
	.go_inval = rgrp_go_inval,
	.go_lock = rgrp_go_lock,
	.go_unlock = rgrp_go_unlock,
	.go_dump = gfs2_rgrp_dump,
	.go_type = LM_TYPE_RGRP,
	.go_min_hold_time = HZ / 5,
	.go_flags = GLOF_ASPACE,
};

const struct gfs2_glock_operations gfs2_trans_glops = {
	.go_xmote_th = trans_go_sync,
	.go_xmote_bh = trans_go_xmote_bh,
	.go_demote_ok = trans_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,
};

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

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,
};

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,
};