allow coexistance of N build and AC build.

[tomato.git] / release / src-rt-6.x / linux / linux-2.6 / fs / gfs2 / meta_io.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/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/delay.h>
#include <linux/bio.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"
#include "ops_address.h"

static int aspace_get_block(struct inode *inode, sector_t lblock,
                            struct buffer_head *bh_result, int create)
{
        gfs2_assert_warn(inode->i_sb->s_fs_info, 0);
        return -EOPNOTSUPP;
}

static int gfs2_aspace_writepage(struct page *page,
                                 struct writeback_control *wbc)
{
        return block_write_full_page(page, aspace_get_block, wbc);
}

static const struct address_space_operations aspace_aops = {
        .writepage = gfs2_aspace_writepage,
        .releasepage = gfs2_releasepage,
};

/**
 * gfs2_aspace_get - Create and initialize a struct inode structure
 * @sdp: the filesystem the aspace is in
 *
 * Right now a struct inode is just a struct inode.  Maybe Linux
 * will supply a more lightweight address space construct (that works)
 * in the future.
 *
 * Make sure pages/buffers in this aspace aren't in high memory.
 *
 * Returns: the aspace
 */

struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
{
        struct inode *aspace;

        aspace = new_inode(sdp->sd_vfs);
        if (aspace) {
                mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
                aspace->i_mapping->a_ops = &aspace_aops;
                aspace->i_size = ~0ULL;
                aspace->i_private = NULL;
                insert_inode_hash(aspace);
        }
        return aspace;
}

void gfs2_aspace_put(struct inode *aspace)
{
        remove_inode_hash(aspace);
        iput(aspace);
}

/**
 * gfs2_meta_inval - Invalidate all buffers associated with a glock
 * @gl: the glock
 *
 */

void gfs2_meta_inval(struct gfs2_glock *gl)
{
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct inode *aspace = gl->gl_aspace;
        struct address_space *mapping = gl->gl_aspace->i_mapping;

        gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));

        atomic_inc(&aspace->i_writecount);
        truncate_inode_pages(mapping, 0);
        atomic_dec(&aspace->i_writecount);

        gfs2_assert_withdraw(sdp, !mapping->nrpages);
}

/**
 * gfs2_meta_sync - Sync all buffers associated with a glock
 * @gl: The glock
 *
 */

void gfs2_meta_sync(struct gfs2_glock *gl)
{
        struct address_space *mapping = gl->gl_aspace->i_mapping;
        int error;

        filemap_fdatawrite(mapping);
        error = filemap_fdatawait(mapping);

        if (error)
                gfs2_io_error(gl->gl_sbd);
}

/**
 * getbuf - Get a buffer with a given address space
 * @gl: the glock
 * @blkno: the block number (filesystem scope)
 * @create: 1 if the buffer should be created
 *
 * Returns: the buffer
 */

static struct buffer_head *getbuf(struct gfs2_glock *gl, u64 blkno, int create)
{
        struct address_space *mapping = gl->gl_aspace->i_mapping;
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct page *page;
        struct buffer_head *bh;
        unsigned int shift;
        unsigned long index;
        unsigned int bufnum;

        shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
        index = blkno >> shift;             /* convert block to page */
        bufnum = blkno - (index << shift);  /* block buf index within page */

        if (create) {
                for (;;) {
                        page = grab_cache_page(mapping, index);
                        if (page)
                                break;
                        yield();
                }
        } else {
                page = find_lock_page(mapping, index);
                if (!page)
                        return NULL;
        }

        if (!page_has_buffers(page))
                create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);

        /* Locate header for our buffer within our page */
        for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
                /* Do nothing */;
        get_bh(bh);

        if (!buffer_mapped(bh))
                map_bh(bh, sdp->sd_vfs, blkno);

        unlock_page(page);
        mark_page_accessed(page);
        page_cache_release(page);

        return bh;
}

static void meta_prep_new(struct buffer_head *bh)
{
        struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;

        lock_buffer(bh);
        clear_buffer_dirty(bh);
        set_buffer_uptodate(bh);
        unlock_buffer(bh);

        mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
}

/**
 * gfs2_meta_new - Get a block
 * @gl: The glock associated with this block
 * @blkno: The block number
 *
 * Returns: The buffer
 */

struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
{
        struct buffer_head *bh;
        bh = getbuf(gl, blkno, CREATE);
        meta_prep_new(bh);
        return bh;
}

/**
 * gfs2_meta_read - Read a block from disk
 * @gl: The glock covering the block
 * @blkno: The block number
 * @flags: flags
 * @bhp: the place where the buffer is returned (NULL on failure)
 *
 * Returns: errno
 */

int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
                   struct buffer_head **bhp)
{
        *bhp = getbuf(gl, blkno, CREATE);
        if (!buffer_uptodate(*bhp))
                ll_rw_block(READ_META, 1, bhp);
        if (flags & DIO_WAIT) {
                int error = gfs2_meta_wait(gl->gl_sbd, *bhp);
                if (error) {
                        brelse(*bhp);
                        return error;
                }
        }

        return 0;
}

/**
 * gfs2_meta_wait - Reread a block from disk
 * @sdp: the filesystem
 * @bh: The block to wait for
 *
 * Returns: errno
 */

int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
                return -EIO;

        wait_on_buffer(bh);

        if (!buffer_uptodate(bh)) {
                struct gfs2_trans *tr = current->journal_info;
                if (tr && tr->tr_touched)
                        gfs2_io_error_bh(sdp, bh);
                return -EIO;
        }
        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
                return -EIO;

        return 0;
}

/**
 * gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
 * @gl: the glock the buffer belongs to
 * @bh: The buffer to be attached to
 * @meta: Flag to indicate whether its metadata or not
 */

void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
                         int meta)
{
        struct gfs2_bufdata *bd;

        if (meta)
                lock_page(bh->b_page);

        if (bh->b_private) {
                if (meta)
                        unlock_page(bh->b_page);
                return;
        }

        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_tr);
        if (meta)
                lops_init_le(&bd->bd_le, &gfs2_buf_lops);
        else
                lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
        bh->b_private = bd;

        if (meta)
                unlock_page(bh->b_page);
}

/**
 * gfs2_pin - Pin a buffer in memory
 * @sdp: the filesystem the buffer belongs to
 * @bh: The buffer to be pinned
 *
 */

void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
        struct gfs2_bufdata *bd = bh->b_private;

        gfs2_assert_withdraw(sdp, test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags));

        if (test_set_buffer_pinned(bh))
                gfs2_assert_withdraw(sdp, 0);

        wait_on_buffer(bh);

        /* If this buffer is in the AIL and it has already been written
           to in-place disk block, remove it from the AIL. */

        gfs2_log_lock(sdp);
        if (bd->bd_ail && !buffer_in_io(bh))
                list_move(&bd->bd_ail_st_list, &bd->bd_ail->ai_ail2_list);
        gfs2_log_unlock(sdp);

        clear_buffer_dirty(bh);
        wait_on_buffer(bh);

        if (!buffer_uptodate(bh))
                gfs2_io_error_bh(sdp, bh);

        get_bh(bh);
}

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

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

        gfs2_assert_withdraw(sdp, buffer_uptodate(bh));

        if (!buffer_pinned(bh))
                gfs2_assert_withdraw(sdp, 0);

        mark_buffer_dirty(bh);
        clear_buffer_pinned(bh);

        gfs2_log_lock(sdp);
        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);
        gfs2_log_unlock(sdp);
}

/**
 * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
 * @ip: the inode who owns the buffers
 * @bstart: the first buffer in the run
 * @blen: the number of buffers in the run
 *
 */

void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head *bh;

        while (blen) {
                bh = getbuf(ip->i_gl, bstart, NO_CREATE);
                if (bh) {
                        struct gfs2_bufdata *bd = bh->b_private;

                        if (test_clear_buffer_pinned(bh)) {
                                struct gfs2_trans *tr = current->journal_info;
                                gfs2_log_lock(sdp);
                                list_del_init(&bd->bd_le.le_list);
                                gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
                                sdp->sd_log_num_buf--;
                                gfs2_log_unlock(sdp);
                                tr->tr_num_buf_rm++;
                                brelse(bh);
                        }
                        if (bd) {
                                gfs2_log_lock(sdp);
                                if (bd->bd_ail) {
                                        u64 blkno = bh->b_blocknr;
                                        bd->bd_ail = NULL;
                                        list_del(&bd->bd_ail_st_list);
                                        list_del(&bd->bd_ail_gl_list);
                                        atomic_dec(&bd->bd_gl->gl_ail_count);
                                        brelse(bh);
                                        gfs2_log_unlock(sdp);
                                        gfs2_trans_add_revoke(sdp, blkno);
                                } else
                                        gfs2_log_unlock(sdp);
                        }

                        lock_buffer(bh);
                        clear_buffer_dirty(bh);
                        clear_buffer_uptodate(bh);
                        unlock_buffer(bh);

                        brelse(bh);
                }

                bstart++;
                blen--;
        }
}

/**
 * gfs2_meta_cache_flush - get rid of any references on buffers for this inode
 * @ip: The GFS2 inode
 *
 * This releases buffers that are in the most-recently-used array of
 * blocks used for indirect block addressing for this inode.
 */

void gfs2_meta_cache_flush(struct gfs2_inode *ip)
{
        struct buffer_head **bh_slot;
        unsigned int x;

        spin_lock(&ip->i_spin);

        for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
                bh_slot = &ip->i_cache[x];
                if (!*bh_slot)
                        break;
                brelse(*bh_slot);
                *bh_slot = NULL;
        }

        spin_unlock(&ip->i_spin);
}

/**
 * gfs2_meta_indirect_buffer - Get a metadata buffer
 * @ip: The GFS2 inode
 * @height: The level of this buf in the metadata (indir addr) tree (if any)
 * @num: The block number (device relative) of the buffer
 * @new: Non-zero if we may create a new buffer
 * @bhp: the buffer is returned here
 *
 * Try to use the gfs2_inode's MRU metadata tree cache.
 *
 * Returns: errno
 */

int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
                              int new, struct buffer_head **bhp)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_glock *gl = ip->i_gl;
        struct buffer_head *bh = NULL, **bh_slot = ip->i_cache + height;
        int in_cache = 0;

        BUG_ON(!gl);
        BUG_ON(!sdp);

        spin_lock(&ip->i_spin);
        if (*bh_slot && (*bh_slot)->b_blocknr == num) {
                bh = *bh_slot;
                get_bh(bh);
                in_cache = 1;
        }
        spin_unlock(&ip->i_spin);

        if (!bh)
                bh = getbuf(gl, num, CREATE);

        if (!bh)
                return -ENOBUFS;

        if (new) {
                if (gfs2_assert_warn(sdp, height))
                        goto err;
                meta_prep_new(bh);
                gfs2_trans_add_bh(ip->i_gl, bh, 1);
                gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
                gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
        } else {
                u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
                if (!buffer_uptodate(bh)) {
                        ll_rw_block(READ_META, 1, &bh);
                        if (gfs2_meta_wait(sdp, bh))
                                goto err;
                }
                if (gfs2_metatype_check(sdp, bh, mtype))
                        goto err;
        }

        if (!in_cache) {
                spin_lock(&ip->i_spin);
                if (*bh_slot)
                        brelse(*bh_slot);
                *bh_slot = bh;
                get_bh(bh);
                spin_unlock(&ip->i_spin);
        }

        *bhp = bh;
        return 0;
err:
        brelse(bh);
        return -EIO;
}

/**
 * gfs2_meta_ra - start readahead on an extent of a file
 * @gl: the glock the blocks belong to
 * @dblock: the starting disk block
 * @extlen: the number of blocks in the extent
 *
 * returns: the first buffer in the extent
 */

struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
{
        struct gfs2_sbd *sdp = gl->gl_sbd;
        struct buffer_head *first_bh, *bh;
        u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
                          sdp->sd_sb.sb_bsize_shift;

        BUG_ON(!extlen);

        if (max_ra < 1)
                max_ra = 1;
        if (extlen > max_ra)
                extlen = max_ra;

        first_bh = getbuf(gl, dblock, CREATE);

        if (buffer_uptodate(first_bh))
                goto out;
        if (!buffer_locked(first_bh))
                ll_rw_block(READ_META, 1, &first_bh);

        dblock++;
        extlen--;

        while (extlen) {
                bh = getbuf(gl, dblock, CREATE);

                if (!buffer_uptodate(bh) && !buffer_locked(bh))
                        ll_rw_block(READA, 1, &bh);
                brelse(bh);
                dblock++;
                extlen--;
                if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
                        goto out;
        }

        wait_on_buffer(first_bh);
out:
        return first_bh;
}