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![Alexey Dobriyan](/assets/img/avatar_default.png)
[akpm@linux-foundation.org: fix KVM] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
565 lines
14 KiB
C
565 lines
14 KiB
C
/*
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* mdt.c - meta data file for NILFS
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Written by Ryusuke Konishi <ryusuke@osrg.net>
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*/
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#include <linux/buffer_head.h>
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#include <linux/mpage.h>
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#include <linux/mm.h>
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#include <linux/writeback.h>
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#include <linux/backing-dev.h>
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#include <linux/swap.h>
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#include "nilfs.h"
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#include "segment.h"
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#include "page.h"
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#include "mdt.h"
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#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
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#define INIT_UNUSED_INODE_FIELDS
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static int
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nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
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struct buffer_head *bh,
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void (*init_block)(struct inode *,
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struct buffer_head *, void *))
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{
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struct nilfs_inode_info *ii = NILFS_I(inode);
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void *kaddr;
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int ret;
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/* Caller exclude read accesses using page lock */
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/* set_buffer_new(bh); */
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bh->b_blocknr = 0;
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ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
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if (unlikely(ret))
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return ret;
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set_buffer_mapped(bh);
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kaddr = kmap_atomic(bh->b_page, KM_USER0);
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memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits);
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if (init_block)
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init_block(inode, bh, kaddr);
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flush_dcache_page(bh->b_page);
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kunmap_atomic(kaddr, KM_USER0);
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set_buffer_uptodate(bh);
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nilfs_mark_buffer_dirty(bh);
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nilfs_mdt_mark_dirty(inode);
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return 0;
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}
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static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
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struct buffer_head **out_bh,
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void (*init_block)(struct inode *,
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struct buffer_head *,
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void *))
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{
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struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
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struct super_block *sb = inode->i_sb;
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struct nilfs_transaction_info ti;
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struct buffer_head *bh;
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int err;
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if (!sb) {
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/*
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* Make sure this function is not called from any
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* read-only context.
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*/
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if (!nilfs->ns_writer) {
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WARN_ON(1);
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err = -EROFS;
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goto out;
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}
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sb = nilfs->ns_writer->s_super;
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}
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nilfs_transaction_begin(sb, &ti, 0);
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err = -ENOMEM;
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bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
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if (unlikely(!bh))
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goto failed_unlock;
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err = -EEXIST;
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if (buffer_uptodate(bh))
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goto failed_bh;
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wait_on_buffer(bh);
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if (buffer_uptodate(bh))
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goto failed_bh;
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bh->b_bdev = nilfs->ns_bdev;
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err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
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if (likely(!err)) {
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get_bh(bh);
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*out_bh = bh;
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}
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failed_bh:
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unlock_page(bh->b_page);
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page_cache_release(bh->b_page);
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brelse(bh);
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failed_unlock:
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if (likely(!err))
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err = nilfs_transaction_commit(sb);
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else
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nilfs_transaction_abort(sb);
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out:
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return err;
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}
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static int
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nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
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int mode, struct buffer_head **out_bh)
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{
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struct buffer_head *bh;
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__u64 blknum = 0;
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int ret = -ENOMEM;
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bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
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if (unlikely(!bh))
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goto failed;
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ret = -EEXIST; /* internal code */
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if (buffer_uptodate(bh))
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goto out;
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if (mode == READA) {
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if (!trylock_buffer(bh)) {
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ret = -EBUSY;
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goto failed_bh;
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}
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} else /* mode == READ */
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lock_buffer(bh);
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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goto out;
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}
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ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
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if (unlikely(ret)) {
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unlock_buffer(bh);
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goto failed_bh;
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}
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bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
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bh->b_blocknr = (sector_t)blknum;
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set_buffer_mapped(bh);
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bh->b_end_io = end_buffer_read_sync;
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get_bh(bh);
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submit_bh(mode, bh);
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ret = 0;
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out:
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get_bh(bh);
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*out_bh = bh;
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failed_bh:
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unlock_page(bh->b_page);
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page_cache_release(bh->b_page);
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brelse(bh);
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failed:
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return ret;
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}
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static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
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struct buffer_head **out_bh)
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{
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struct buffer_head *first_bh, *bh;
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unsigned long blkoff;
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int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
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int err;
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err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
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if (err == -EEXIST) /* internal code */
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goto out;
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if (unlikely(err))
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goto failed;
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blkoff = block + 1;
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for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
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err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
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if (likely(!err || err == -EEXIST))
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brelse(bh);
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else if (err != -EBUSY)
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break; /* abort readahead if bmap lookup failed */
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if (!buffer_locked(first_bh))
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goto out_no_wait;
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}
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wait_on_buffer(first_bh);
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out_no_wait:
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err = -EIO;
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if (!buffer_uptodate(first_bh))
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goto failed_bh;
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out:
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*out_bh = first_bh;
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return 0;
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failed_bh:
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brelse(first_bh);
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failed:
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return err;
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}
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/**
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* nilfs_mdt_get_block - read or create a buffer on meta data file.
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* @inode: inode of the meta data file
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* @blkoff: block offset
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* @create: create flag
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* @init_block: initializer used for newly allocated block
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* @out_bh: output of a pointer to the buffer_head
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*
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* nilfs_mdt_get_block() looks up the specified buffer and tries to create
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* a new buffer if @create is not zero. On success, the returned buffer is
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* assured to be either existing or formatted using a buffer lock on success.
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* @out_bh is substituted only when zero is returned.
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*
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* Return Value: On success, it returns 0. On error, the following negative
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* error code is returned.
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*
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* %-ENOMEM - Insufficient memory available.
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*
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* %-EIO - I/O error
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*
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* %-ENOENT - the specified block does not exist (hole block)
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*
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* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
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*
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* %-EROFS - Read only filesystem (for create mode)
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*/
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int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
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void (*init_block)(struct inode *,
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struct buffer_head *, void *),
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struct buffer_head **out_bh)
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{
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int ret;
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/* Should be rewritten with merging nilfs_mdt_read_block() */
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retry:
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ret = nilfs_mdt_read_block(inode, blkoff, out_bh);
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if (!create || ret != -ENOENT)
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return ret;
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ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
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if (unlikely(ret == -EEXIST)) {
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/* create = 0; */ /* limit read-create loop retries */
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goto retry;
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}
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return ret;
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}
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/**
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* nilfs_mdt_delete_block - make a hole on the meta data file.
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* @inode: inode of the meta data file
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* @block: block offset
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*
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* Return Value: On success, zero is returned.
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* On error, one of the following negative error code is returned.
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*
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* %-ENOMEM - Insufficient memory available.
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*
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* %-EIO - I/O error
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*
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* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
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*/
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int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
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{
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struct nilfs_inode_info *ii = NILFS_I(inode);
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int err;
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err = nilfs_bmap_delete(ii->i_bmap, block);
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if (!err || err == -ENOENT) {
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nilfs_mdt_mark_dirty(inode);
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nilfs_mdt_forget_block(inode, block);
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}
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return err;
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}
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/**
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* nilfs_mdt_forget_block - discard dirty state and try to remove the page
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* @inode: inode of the meta data file
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* @block: block offset
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*
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* nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
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* tries to release the page including the buffer from a page cache.
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*
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* Return Value: On success, 0 is returned. On error, one of the following
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* negative error code is returned.
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*
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* %-EBUSY - page has an active buffer.
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*
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* %-ENOENT - page cache has no page addressed by the offset.
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*/
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int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
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{
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pgoff_t index = (pgoff_t)block >>
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(PAGE_CACHE_SHIFT - inode->i_blkbits);
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struct page *page;
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unsigned long first_block;
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int ret = 0;
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int still_dirty;
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page = find_lock_page(inode->i_mapping, index);
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if (!page)
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return -ENOENT;
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wait_on_page_writeback(page);
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first_block = (unsigned long)index <<
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(PAGE_CACHE_SHIFT - inode->i_blkbits);
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if (page_has_buffers(page)) {
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struct buffer_head *bh;
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bh = nilfs_page_get_nth_block(page, block - first_block);
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nilfs_forget_buffer(bh);
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}
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still_dirty = PageDirty(page);
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unlock_page(page);
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page_cache_release(page);
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if (still_dirty ||
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invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
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ret = -EBUSY;
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return ret;
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}
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/**
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* nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty.
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* @inode: inode of the meta data file
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* @block: block offset
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*
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* Return Value: On success, it returns 0. On error, the following negative
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* error code is returned.
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*
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* %-ENOMEM - Insufficient memory available.
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*
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* %-EIO - I/O error
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*
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* %-ENOENT - the specified block does not exist (hole block)
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*
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* %-EINVAL - bmap is broken. (the caller should call nilfs_error())
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*/
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int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block)
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{
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struct buffer_head *bh;
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int err;
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err = nilfs_mdt_read_block(inode, block, &bh);
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if (unlikely(err))
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return err;
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nilfs_mark_buffer_dirty(bh);
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nilfs_mdt_mark_dirty(inode);
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brelse(bh);
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return 0;
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}
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int nilfs_mdt_fetch_dirty(struct inode *inode)
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{
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struct nilfs_inode_info *ii = NILFS_I(inode);
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if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
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set_bit(NILFS_I_DIRTY, &ii->i_state);
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return 1;
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}
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return test_bit(NILFS_I_DIRTY, &ii->i_state);
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}
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static int
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nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
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{
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struct inode *inode = container_of(page->mapping,
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struct inode, i_data);
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struct super_block *sb = inode->i_sb;
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struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
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struct nilfs_sb_info *writer = NULL;
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int err = 0;
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redirty_page_for_writepage(wbc, page);
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unlock_page(page);
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if (page->mapping->assoc_mapping)
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return 0; /* Do not request flush for shadow page cache */
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if (!sb) {
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down_read(&nilfs->ns_writer_sem);
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writer = nilfs->ns_writer;
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if (!writer) {
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up_read(&nilfs->ns_writer_sem);
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return -EROFS;
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}
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sb = writer->s_super;
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}
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if (wbc->sync_mode == WB_SYNC_ALL)
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err = nilfs_construct_segment(sb);
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else if (wbc->for_reclaim)
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nilfs_flush_segment(sb, inode->i_ino);
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if (writer)
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up_read(&nilfs->ns_writer_sem);
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return err;
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}
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static const struct address_space_operations def_mdt_aops = {
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.writepage = nilfs_mdt_write_page,
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.sync_page = block_sync_page,
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};
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static const struct inode_operations def_mdt_iops;
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static const struct file_operations def_mdt_fops;
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/*
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* NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile,
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* ifile, or gcinodes. This allows the B-tree code and segment constructor
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* to treat them like regular files, and this helps to simplify the
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* implementation.
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* On the other hand, some of the pseudo inodes have an irregular point:
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* They don't have valid inode->i_sb pointer because their lifetimes are
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* longer than those of the super block structs; they may continue for
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* several consecutive mounts/umounts. This would need discussions.
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*/
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struct inode *
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nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
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ino_t ino, gfp_t gfp_mask)
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{
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struct inode *inode = nilfs_alloc_inode_common(nilfs);
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if (!inode)
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return NULL;
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else {
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struct address_space * const mapping = &inode->i_data;
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struct nilfs_mdt_info *mi = kzalloc(sizeof(*mi), GFP_NOFS);
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if (!mi) {
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nilfs_destroy_inode(inode);
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return NULL;
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}
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mi->mi_nilfs = nilfs;
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init_rwsem(&mi->mi_sem);
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inode->i_sb = sb; /* sb may be NULL for some meta data files */
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inode->i_blkbits = nilfs->ns_blocksize_bits;
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inode->i_flags = 0;
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atomic_set(&inode->i_count, 1);
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inode->i_nlink = 1;
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inode->i_ino = ino;
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inode->i_mode = S_IFREG;
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inode->i_private = mi;
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#ifdef INIT_UNUSED_INODE_FIELDS
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atomic_set(&inode->i_writecount, 0);
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inode->i_size = 0;
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inode->i_blocks = 0;
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inode->i_bytes = 0;
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inode->i_generation = 0;
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#ifdef CONFIG_QUOTA
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memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
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#endif
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inode->i_pipe = NULL;
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inode->i_bdev = NULL;
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inode->i_cdev = NULL;
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inode->i_rdev = 0;
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#ifdef CONFIG_SECURITY
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inode->i_security = NULL;
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#endif
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inode->dirtied_when = 0;
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INIT_LIST_HEAD(&inode->i_list);
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INIT_LIST_HEAD(&inode->i_sb_list);
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inode->i_state = 0;
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#endif
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spin_lock_init(&inode->i_lock);
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mutex_init(&inode->i_mutex);
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init_rwsem(&inode->i_alloc_sem);
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mapping->host = NULL; /* instead of inode */
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mapping->flags = 0;
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mapping_set_gfp_mask(mapping, gfp_mask);
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mapping->assoc_mapping = NULL;
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mapping->backing_dev_info = nilfs->ns_bdi;
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inode->i_mapping = mapping;
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}
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return inode;
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}
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struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
|
|
ino_t ino)
|
|
{
|
|
struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino,
|
|
NILFS_MDT_GFP);
|
|
|
|
if (!inode)
|
|
return NULL;
|
|
|
|
inode->i_op = &def_mdt_iops;
|
|
inode->i_fop = &def_mdt_fops;
|
|
inode->i_mapping->a_ops = &def_mdt_aops;
|
|
return inode;
|
|
}
|
|
|
|
void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size,
|
|
unsigned header_size)
|
|
{
|
|
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
|
|
|
|
mi->mi_entry_size = entry_size;
|
|
mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size;
|
|
mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
|
|
}
|
|
|
|
void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow)
|
|
{
|
|
shadow->i_mapping->assoc_mapping = orig->i_mapping;
|
|
NILFS_I(shadow)->i_btnode_cache.assoc_mapping =
|
|
&NILFS_I(orig)->i_btnode_cache;
|
|
}
|
|
|
|
void nilfs_mdt_clear(struct inode *inode)
|
|
{
|
|
struct nilfs_inode_info *ii = NILFS_I(inode);
|
|
|
|
invalidate_mapping_pages(inode->i_mapping, 0, -1);
|
|
truncate_inode_pages(inode->i_mapping, 0);
|
|
|
|
nilfs_bmap_clear(ii->i_bmap);
|
|
nilfs_btnode_cache_clear(&ii->i_btnode_cache);
|
|
}
|
|
|
|
void nilfs_mdt_destroy(struct inode *inode)
|
|
{
|
|
struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
|
|
|
|
kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
|
|
kfree(mdi);
|
|
nilfs_destroy_inode(inode);
|
|
}
|