2
* gcinode.c - dummy inodes to buffer blocks for garbage collection
4
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6
* This program is free software; you can redistribute it and/or modify
7
* it under the terms of the GNU General Public License as published by
8
* the Free Software Foundation; either version 2 of the License, or
9
* (at your option) any later version.
11
* This program is distributed in the hope that it will be useful,
12
* but WITHOUT ANY WARRANTY; without even the implied warranty of
13
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14
* GNU General Public License for more details.
16
* You should have received a copy of the GNU General Public License
17
* along with this program; if not, write to the Free Software
18
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20
* Written by Seiji Kihara <kihara@osrg.net>, Amagai Yoshiji <amagai@osrg.net>,
21
* and Ryusuke Konishi <ryusuke@osrg.net>.
22
* Revised by Ryusuke Konishi <ryusuke@osrg.net>.
26
* This file adds the cache of on-disk blocks to be moved in garbage
27
* collection. The disk blocks are held with dummy inodes (called
28
* gcinodes), and this file provides lookup function of the dummy
29
* inodes and their buffer read function.
31
* Since NILFS2 keeps up multiple checkpoints/snapshots accross GC, it
32
* has to treat blocks that belong to a same file but have different
33
* checkpoint numbers. To avoid interference among generations, dummy
34
* inodes are managed separatly from actual inodes, and their lookup
35
* function (nilfs_gc_iget) is designed to be specified with a
36
* checkpoint number argument as well as an inode number.
38
* Buffers and pages held by the dummy inodes will be released each
39
* time after they are copied to a new log. Dirty blocks made on the
40
* current generation and the blocks to be moved by GC never overlap
41
* because the dirty blocks make a new generation; they rather must be
42
* written individually.
45
#include <linux/buffer_head.h>
46
#include <linux/mpage.h>
47
#include <linux/hash.h>
48
#include <linux/swap.h>
55
static struct address_space_operations def_gcinode_aops = {
56
.sync_page = block_sync_page,
60
* nilfs_gccache_submit_read_data() - add data buffer and submit read request
62
* @blkoff - dummy offset treated as the key for the page cache
63
* @pbn - physical block number of the block
64
* @vbn - virtual block number of the block, 0 for non-virtual block
65
* @out_bh - indirect pointer to a buffer_head struct to receive the results
67
* Description: nilfs_gccache_submit_read_data() registers the data buffer
68
* specified by @pbn to the GC pagecache with the key @blkoff.
69
* This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer.
71
* Return Value: On success, 0 is returned. On Error, one of the following
72
* negative error code is returned.
76
* %-ENOMEM - Insufficient amount of memory available.
78
* %-ENOENT - The block specified with @pbn does not exist.
80
int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
81
sector_t pbn, __u64 vbn,
82
struct buffer_head **out_bh)
84
struct buffer_head *bh;
87
bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
91
if (buffer_uptodate(bh))
95
struct inode *dat_inode = NILFS_I_NILFS(inode)->ns_dat;
96
/* use original dat, not gc dat. */
97
err = nilfs_dat_translate(dat_inode, vbn, &pbn);
98
if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */
105
if (buffer_uptodate(bh)) {
110
if (!buffer_mapped(bh)) {
111
bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
112
set_buffer_mapped(bh);
115
bh->b_end_io = end_buffer_read_sync;
125
unlock_page(bh->b_page);
126
page_cache_release(bh->b_page);
131
* nilfs_gccache_submit_read_node() - add node buffer and submit read request
133
* @pbn - physical block number for the block
134
* @vbn - virtual block number for the block
135
* @out_bh - indirect pointer to a buffer_head struct to receive the results
137
* Description: nilfs_gccache_submit_read_node() registers the node buffer
138
* specified by @vbn to the GC pagecache. @pbn can be supplied by the
139
* caller to avoid translation of the disk block address.
141
* Return Value: On success, 0 is returned. On Error, one of the following
142
* negative error code is returned.
146
* %-ENOMEM - Insufficient amount of memory available.
148
int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
149
__u64 vbn, struct buffer_head **out_bh)
151
int ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
152
vbn ? : pbn, pbn, out_bh, 0);
153
if (ret == -EEXIST) /* internal code (cache hit) */
158
int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
161
if (!buffer_uptodate(bh))
163
if (buffer_dirty(bh))
166
if (buffer_nilfs_node(bh))
167
nilfs_btnode_mark_dirty(bh);
169
nilfs_mdt_mark_buffer_dirty(bh);
174
* nilfs_init_gccache() - allocate and initialize gc_inode hash table
177
* Return Value: On success, 0.
178
* On error, a negative error code is returned.
180
int nilfs_init_gccache(struct the_nilfs *nilfs)
184
BUG_ON(nilfs->ns_gc_inodes_h);
186
INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
188
nilfs->ns_gc_inodes_h =
189
kmalloc(sizeof(struct hlist_head) * NILFS_GCINODE_HASH_SIZE,
191
if (nilfs->ns_gc_inodes_h == NULL)
194
for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++)
195
INIT_HLIST_HEAD(&nilfs->ns_gc_inodes_h[loop]);
200
* nilfs_destroy_gccache() - free gc_inode hash table
203
void nilfs_destroy_gccache(struct the_nilfs *nilfs)
205
if (nilfs->ns_gc_inodes_h) {
206
nilfs_remove_all_gcinode(nilfs);
207
kfree(nilfs->ns_gc_inodes_h);
208
nilfs->ns_gc_inodes_h = NULL;
212
static struct inode *alloc_gcinode(struct the_nilfs *nilfs, ino_t ino,
215
struct inode *inode = nilfs_mdt_new_common(nilfs, NULL, ino, GFP_NOFS);
216
struct nilfs_inode_info *ii;
223
inode->i_mapping->a_ops = &def_gcinode_aops;
228
ii->i_state = 1 << NILFS_I_GCINODE;
230
nilfs_bmap_init_gc(ii->i_bmap);
235
static unsigned long ihash(ino_t ino, __u64 cno)
237
return hash_long((unsigned long)((ino << 2) + cno),
238
NILFS_GCINODE_HASH_BITS);
242
* nilfs_gc_iget() - find or create gc inode with specified (ino,cno)
244
struct inode *nilfs_gc_iget(struct the_nilfs *nilfs, ino_t ino, __u64 cno)
246
struct hlist_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno);
247
struct hlist_node *node;
250
hlist_for_each_entry(inode, node, head, i_hash) {
251
if (inode->i_ino == ino && NILFS_I(inode)->i_cno == cno)
255
inode = alloc_gcinode(nilfs, ino, cno);
257
hlist_add_head(&inode->i_hash, head);
258
list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes);
264
* nilfs_clear_gcinode() - clear and free a gc inode
266
void nilfs_clear_gcinode(struct inode *inode)
268
nilfs_mdt_clear(inode);
269
nilfs_mdt_destroy(inode);
273
* nilfs_remove_all_gcinode() - remove all inodes from the_nilfs
275
void nilfs_remove_all_gcinode(struct the_nilfs *nilfs)
277
struct hlist_head *head = nilfs->ns_gc_inodes_h;
278
struct hlist_node *node, *n;
282
for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++, head++) {
283
hlist_for_each_entry_safe(inode, node, n, head, i_hash) {
284
hlist_del_init(&inode->i_hash);
285
list_del_init(&NILFS_I(inode)->i_dirty);
286
nilfs_clear_gcinode(inode); /* might sleep */