path: root/fs/gfs2/lops.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 version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/mempool.h>
#include <linux/gfs2_ondisk.h>
#include <linux/bio.h>
#include <linux/fs.h>

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

/**
 * gfs2_pin - Pin a buffer in memory
 * @sdp: The superblock
 * @bh: The buffer to be pinned
 *
 * The log lock must be held when calling this function
 */
static void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
	struct gfs2_bufdata *bd;

	BUG_ON(!current->journal_info);

	clear_buffer_dirty(bh);
	if (test_set_buffer_pinned(bh))
		gfs2_assert_withdraw(sdp, 0);
	if (!buffer_uptodate(bh))
		gfs2_io_error_bh(sdp, bh);
	bd = bh->b_private;
	/* If this buffer is in the AIL and it has already been written
	 * to in-place disk block, remove it from the AIL.
	 */
	spin_lock(&sdp->sd_ail_lock);
	if (bd->bd_ail)
		list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
	spin_unlock(&sdp->sd_ail_lock);
	get_bh(bh);
	atomic_inc(&sdp->sd_log_pinned);
	trace_gfs2_pin(bd, 1);
}

static bool buffer_is_rgrp(const struct gfs2_bufdata *bd)
{
	return bd->bd_gl->gl_name.ln_type == LM_TYPE_RGRP;
}

static void maybe_release_space(struct gfs2_bufdata *bd)
{
	struct gfs2_glock *gl = bd->bd_gl;
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct gfs2_rgrpd *rgd = gl->gl_object;
	unsigned int index = bd->bd_bh->b_blocknr - gl->gl_name.ln_number;
	struct gfs2_bitmap *bi = rgd->rd_bits + index;

	if (bi->bi_clone == 0)
		return;
	if (sdp->sd_args.ar_discard)
		gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bd->bd_bh, bi, 1, NULL);
	memcpy(bi->bi_clone + bi->bi_offset,
	       bd->bd_bh->b_data + bi->bi_offset, bi->bi_len);
	clear_bit(GBF_FULL, &bi->bi_flags);
	rgd->rd_free_clone = rgd->rd_free;
}

/**
 * gfs2_unpin - Unpin a buffer
 * @sdp: the filesystem the buffer belongs to
 * @bh: The buffer to unpin
 * @ai:
 * @flags: The inode dirty flags
 *
 */

static void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
		       struct gfs2_ail *ai)
{
	struct gfs2_bufdata *bd = bh->b_private;

	BUG_ON(!buffer_uptodate(bh));
	BUG_ON(!buffer_pinned(bh));

	lock_buffer(bh);
	mark_buffer_dirty(bh);
	clear_buffer_pinned(bh);

	if (buffer_is_rgrp(bd))
		maybe_release_space(bd);

	spin_lock(&sdp->sd_ail_lock);
	if (bd->bd_ail) {
		list_del(&bd->bd_ail_st_list);
		brelse(bh);
	} else {
		struct gfs2_glock *gl = bd->bd_gl;
		list_add(&bd->bd_ail_gl_list, &gl->gl_ail_list);
		atomic_inc(&gl->gl_ail_count);
	}
	bd->bd_ail = ai;
	list_add(&bd->bd_ail_st_list, &ai->ai_ail1_list);
	spin_unlock(&sdp->sd_ail_lock);

	clear_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
	trace_gfs2_pin(bd, 0);
	unlock_buffer(bh);
	atomic_dec(&sdp->sd_log_pinned);
}

static void gfs2_log_incr_head(struct gfs2_sbd *sdp)
{
	BUG_ON((sdp->sd_log_flush_head == sdp->sd_log_tail) &&
	       (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;
	}
}

static u64 gfs2_log_bmap(struct gfs2_sbd *sdp)
{
	unsigned int lbn = sdp->sd_log_flush_head;
	struct gfs2_journal_extent *je;
	u64 block;

	list_for_each_entry(je, &sdp->sd_jdesc->extent_list, extent_list) {
		if (lbn >= je->lblock && lbn < je->lblock + je->blocks) {
			block = je->dblock + lbn - je->lblock;
			gfs2_log_incr_head(sdp);
			return block;
		}
	}

	return -1;
}

/**
 * gfs2_end_log_write_bh - end log write of pagecache data with buffers
 * @sdp: The superblock
 * @bvec: The bio_vec
 * @error: The i/o status
 *
 * This finds the relavent buffers and unlocks then and sets the
 * error flag according to the status of the i/o request. This is
 * used when the log is writing data which has an in-place version
 * that is pinned in the pagecache.
 */

static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp