--- /dev/null
+/*
+ * gcinode.c - dummy inodes to buffer blocks for garbage collection
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Written by Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>,
+ * and Ryusuke Konishi <ryusuke@osrg.net>.
+ * Revised by Ryusuke Konishi <ryusuke@osrg.net>.
+ *
+ */
+/*
+ * This file adds the cache of on-disk blocks to be moved in garbage
+ * collection. The disk blocks are held with dummy inodes (called
+ * gcinodes), and this file provides lookup function of the dummy
+ * inodes and their buffer read function.
+ *
+ * Buffers and pages held by the dummy inodes will be released each
+ * time after they are copied to a new log. Dirty blocks made on the
+ * current generation and the blocks to be moved by GC never overlap
+ * because the dirty blocks make a new generation; they rather must be
+ * written individually.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/hash.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include "nilfs.h"
+#include "btree.h"
+#include "btnode.h"
+#include "page.h"
+#include "mdt.h"
+#include "dat.h"
+#include "ifile.h"
+
+/*
+ * nilfs_gccache_submit_read_data() - add data buffer and submit read request
+ * @inode - gc inode
+ * @blkoff - dummy offset treated as the key for the page cache
+ * @pbn - physical block number of the block
+ * @vbn - virtual block number of the block, 0 for non-virtual block
+ * @out_bh - indirect pointer to a buffer_head struct to receive the results
+ *
+ * Description: nilfs_gccache_submit_read_data() registers the data buffer
+ * specified by @pbn to the GC pagecache with the key @blkoff.
+ * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer.
+ *
+ * Return Value: On success, 0 is returned. On Error, one of the following
+ * negative error code is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - The block specified with @pbn does not exist.
+ */
+int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
+ sector_t pbn, __u64 vbn,
+ struct buffer_head **out_bh)
+{
+ struct buffer_head *bh;
+ int err;
+
+ bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
+ if (unlikely(!bh))
+ return -ENOMEM;
+
+ if (buffer_uptodate(bh))
+ goto out;
+
+ if (pbn == 0) {
+ struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
+
+ err = nilfs_dat_translate(nilfs->ns_dat, vbn, &pbn);
+ if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */
+ brelse(bh);
+ goto failed;
+ }
+ }
+
+ lock_buffer(bh);
+ if (buffer_uptodate(bh)) {
+ unlock_buffer(bh);
+ goto out;
+ }
+
+ if (!buffer_mapped(bh)) {
+ bh->b_bdev = inode->i_sb->s_bdev;
+ set_buffer_mapped(bh);
+ }
+ bh->b_blocknr = pbn;
+ bh->b_end_io = end_buffer_read_sync;
+ get_bh(bh);
+ submit_bh(READ, bh);
+ if (vbn)
+ bh->b_blocknr = vbn;
+ out:
+ err = 0;
+ *out_bh = bh;
+
+ failed:
+ unlock_page(bh->b_page);
+ page_cache_release(bh->b_page);
+ return err;
+}
+
+/*
+ * nilfs_gccache_submit_read_node() - add node buffer and submit read request
+ * @inode - gc inode
+ * @pbn - physical block number for the block
+ * @vbn - virtual block number for the block
+ * @out_bh - indirect pointer to a buffer_head struct to receive the results
+ *
+ * Description: nilfs_gccache_submit_read_node() registers the node buffer
+ * specified by @vbn to the GC pagecache. @pbn can be supplied by the
+ * caller to avoid translation of the disk block address.
+ *
+ * Return Value: On success, 0 is returned. On Error, one of the following
+ * negative error code is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ */
+int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
+ __u64 vbn, struct buffer_head **out_bh)
+{
+ int ret;
+
+ ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
+ vbn ? : pbn, pbn, READ, out_bh, &pbn);
+ if (ret == -EEXIST) /* internal code (cache hit) */
+ ret = 0;
+ return ret;
+}
+
+int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
+{
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh))
+ return -EIO;
+ if (buffer_dirty(bh))
+ return -EEXIST;
+
+ if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
+ clear_buffer_uptodate(bh);
+ return -EIO;
+ }
+ mark_buffer_dirty(bh);
+ return 0;
+}
+
+int nilfs_init_gcinode(struct inode *inode)
+{
+ struct nilfs_inode_info *ii = NILFS_I(inode);
+
+ inode->i_mode = S_IFREG;
+ mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
+ inode->i_mapping->a_ops = &empty_aops;
+
+ ii->i_flags = 0;
+ nilfs_bmap_init_gc(ii->i_bmap);
+
+ return 0;
+}
+
+/**
+ * nilfs_remove_all_gcinodes() - remove all unprocessed gc inodes
+ */
+void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
+{
+ struct list_head *head = &nilfs->ns_gc_inodes;
+ struct nilfs_inode_info *ii;
+
+ while (!list_empty(head)) {
+ ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
+ list_del_init(&ii->i_dirty);
+ truncate_inode_pages(&ii->vfs_inode.i_data, 0);
+ nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+ iput(&ii->vfs_inode);
+ }
+}
Code Review / kvmfornfv.git / blobdiff