Commit | Line | Data |
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a3d93f70 | 1 | /* |
047180f2 | 2 | * gcinode.c - dummy inodes to buffer blocks for garbage collection |
a3d93f70 RK |
3 | * |
4 | * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. | |
5 | * | |
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. | |
10 | * | |
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. | |
15 | * | |
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 | |
19 | * | |
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>. | |
23 | * | |
24 | */ | |
047180f2 RK |
25 | /* |
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. | |
30 | * | |
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. | |
37 | * | |
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. | |
43 | */ | |
a3d93f70 RK |
44 | |
45 | #include <linux/buffer_head.h> | |
46 | #include <linux/mpage.h> | |
47 | #include <linux/hash.h> | |
48 | #include <linux/swap.h> | |
49 | #include "nilfs.h" | |
50 | #include "page.h" | |
51 | #include "mdt.h" | |
52 | #include "dat.h" | |
53 | #include "ifile.h" | |
54 | ||
55 | static struct address_space_operations def_gcinode_aops = {}; | |
56 | /* XXX need def_gcinode_iops/fops? */ | |
57 | ||
58 | /* | |
59 | * nilfs_gccache_submit_read_data() - add data buffer and submit read request | |
60 | * @inode - gc inode | |
61 | * @blkoff - dummy offset treated as the key for the page cache | |
62 | * @pbn - physical block number of the block | |
63 | * @vbn - virtual block number of the block, 0 for non-virtual block | |
64 | * @out_bh - indirect pointer to a buffer_head struct to receive the results | |
65 | * | |
66 | * Description: nilfs_gccache_submit_read_data() registers the data buffer | |
67 | * specified by @pbn to the GC pagecache with the key @blkoff. | |
68 | * This function sets @vbn (@pbn if @vbn is zero) in b_blocknr of the buffer. | |
69 | * | |
70 | * Return Value: On success, 0 is returned. On Error, one of the following | |
71 | * negative error code is returned. | |
72 | * | |
73 | * %-EIO - I/O error. | |
74 | * | |
75 | * %-ENOMEM - Insufficient amount of memory available. | |
76 | * | |
77 | * %-ENOENT - The block specified with @pbn does not exist. | |
78 | */ | |
79 | int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff, | |
80 | sector_t pbn, __u64 vbn, | |
81 | struct buffer_head **out_bh) | |
82 | { | |
83 | struct buffer_head *bh; | |
84 | int err; | |
85 | ||
86 | bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); | |
87 | if (unlikely(!bh)) | |
88 | return -ENOMEM; | |
89 | ||
90 | if (buffer_uptodate(bh)) | |
91 | goto out; | |
92 | ||
93 | if (pbn == 0) { | |
94 | struct inode *dat_inode = NILFS_I_NILFS(inode)->ns_dat; | |
95 | /* use original dat, not gc dat. */ | |
96 | err = nilfs_dat_translate(dat_inode, vbn, &pbn); | |
97 | if (unlikely(err)) { /* -EIO, -ENOMEM, -ENOENT */ | |
98 | brelse(bh); | |
99 | goto failed; | |
100 | } | |
101 | } | |
102 | ||
103 | lock_buffer(bh); | |
104 | if (buffer_uptodate(bh)) { | |
105 | unlock_buffer(bh); | |
106 | goto out; | |
107 | } | |
108 | ||
109 | if (!buffer_mapped(bh)) { | |
110 | bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; | |
111 | set_buffer_mapped(bh); | |
112 | } | |
113 | bh->b_blocknr = pbn; | |
114 | bh->b_end_io = end_buffer_read_sync; | |
115 | get_bh(bh); | |
116 | submit_bh(READ, bh); | |
117 | if (vbn) | |
118 | bh->b_blocknr = vbn; | |
119 | out: | |
120 | err = 0; | |
121 | *out_bh = bh; | |
122 | ||
123 | failed: | |
124 | unlock_page(bh->b_page); | |
125 | page_cache_release(bh->b_page); | |
126 | return err; | |
127 | } | |
128 | ||
129 | /* | |
130 | * nilfs_gccache_submit_read_node() - add node buffer and submit read request | |
131 | * @inode - gc inode | |
132 | * @pbn - physical block number for the block | |
133 | * @vbn - virtual block number for the block | |
134 | * @out_bh - indirect pointer to a buffer_head struct to receive the results | |
135 | * | |
136 | * Description: nilfs_gccache_submit_read_node() registers the node buffer | |
137 | * specified by @vbn to the GC pagecache. @pbn can be supplied by the | |
138 | * caller to avoid translation of the disk block address. | |
139 | * | |
140 | * Return Value: On success, 0 is returned. On Error, one of the following | |
141 | * negative error code is returned. | |
142 | * | |
143 | * %-EIO - I/O error. | |
144 | * | |
145 | * %-ENOMEM - Insufficient amount of memory available. | |
146 | */ | |
147 | int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn, | |
148 | __u64 vbn, struct buffer_head **out_bh) | |
149 | { | |
150 | int ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache, | |
151 | vbn ? : pbn, pbn, out_bh, 0); | |
152 | if (ret == -EEXIST) /* internal code (cache hit) */ | |
153 | ret = 0; | |
154 | return ret; | |
155 | } | |
156 | ||
157 | int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh) | |
158 | { | |
159 | wait_on_buffer(bh); | |
160 | if (!buffer_uptodate(bh)) | |
161 | return -EIO; | |
162 | if (buffer_dirty(bh)) | |
163 | return -EEXIST; | |
164 | ||
165 | if (buffer_nilfs_node(bh)) | |
166 | nilfs_btnode_mark_dirty(bh); | |
167 | else | |
168 | nilfs_mdt_mark_buffer_dirty(bh); | |
169 | return 0; | |
170 | } | |
171 | ||
172 | /* | |
173 | * nilfs_init_gccache() - allocate and initialize gc_inode hash table | |
174 | * @nilfs - the_nilfs | |
175 | * | |
176 | * Return Value: On success, 0. | |
177 | * On error, a negative error code is returned. | |
178 | */ | |
179 | int nilfs_init_gccache(struct the_nilfs *nilfs) | |
180 | { | |
181 | int loop; | |
182 | ||
183 | BUG_ON(nilfs->ns_gc_inodes_h); | |
184 | ||
185 | INIT_LIST_HEAD(&nilfs->ns_gc_inodes); | |
186 | ||
187 | nilfs->ns_gc_inodes_h = | |
188 | kmalloc(sizeof(struct hlist_head) * NILFS_GCINODE_HASH_SIZE, | |
189 | GFP_NOFS); | |
190 | if (nilfs->ns_gc_inodes_h == NULL) | |
191 | return -ENOMEM; | |
192 | ||
193 | for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++) | |
194 | INIT_HLIST_HEAD(&nilfs->ns_gc_inodes_h[loop]); | |
195 | return 0; | |
196 | } | |
197 | ||
198 | /* | |
199 | * nilfs_destroy_gccache() - free gc_inode hash table | |
200 | * @nilfs - the nilfs | |
201 | */ | |
202 | void nilfs_destroy_gccache(struct the_nilfs *nilfs) | |
203 | { | |
204 | if (nilfs->ns_gc_inodes_h) { | |
205 | nilfs_remove_all_gcinode(nilfs); | |
206 | kfree(nilfs->ns_gc_inodes_h); | |
207 | nilfs->ns_gc_inodes_h = NULL; | |
208 | } | |
209 | } | |
210 | ||
211 | static struct inode *alloc_gcinode(struct the_nilfs *nilfs, ino_t ino, | |
212 | __u64 cno) | |
213 | { | |
214 | struct inode *inode = nilfs_mdt_new_common(nilfs, NULL, ino, GFP_NOFS); | |
215 | struct nilfs_inode_info *ii; | |
216 | ||
217 | if (!inode) | |
218 | return NULL; | |
219 | ||
220 | inode->i_op = NULL; | |
221 | inode->i_fop = NULL; | |
222 | inode->i_mapping->a_ops = &def_gcinode_aops; | |
223 | ||
224 | ii = NILFS_I(inode); | |
225 | ii->i_cno = cno; | |
226 | ii->i_flags = 0; | |
227 | ii->i_state = 1 << NILFS_I_GCINODE; | |
228 | ii->i_bh = NULL; | |
a3d93f70 RK |
229 | nilfs_bmap_init_gc(ii->i_bmap); |
230 | ||
231 | return inode; | |
232 | } | |
233 | ||
234 | static unsigned long ihash(ino_t ino, __u64 cno) | |
235 | { | |
236 | return hash_long((unsigned long)((ino << 2) + cno), | |
237 | NILFS_GCINODE_HASH_BITS); | |
238 | } | |
239 | ||
240 | /* | |
241 | * nilfs_gc_iget() - find or create gc inode with specified (ino,cno) | |
242 | */ | |
243 | struct inode *nilfs_gc_iget(struct the_nilfs *nilfs, ino_t ino, __u64 cno) | |
244 | { | |
245 | struct hlist_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno); | |
246 | struct hlist_node *node; | |
247 | struct inode *inode; | |
248 | ||
249 | hlist_for_each_entry(inode, node, head, i_hash) { | |
250 | if (inode->i_ino == ino && NILFS_I(inode)->i_cno == cno) | |
251 | return inode; | |
252 | } | |
253 | ||
254 | inode = alloc_gcinode(nilfs, ino, cno); | |
255 | if (likely(inode)) { | |
256 | hlist_add_head(&inode->i_hash, head); | |
257 | list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes); | |
258 | } | |
259 | return inode; | |
260 | } | |
261 | ||
262 | /* | |
263 | * nilfs_clear_gcinode() - clear and free a gc inode | |
264 | */ | |
265 | void nilfs_clear_gcinode(struct inode *inode) | |
266 | { | |
267 | nilfs_mdt_clear(inode); | |
268 | nilfs_mdt_destroy(inode); | |
269 | } | |
270 | ||
271 | /* | |
272 | * nilfs_remove_all_gcinode() - remove all inodes from the_nilfs | |
273 | */ | |
274 | void nilfs_remove_all_gcinode(struct the_nilfs *nilfs) | |
275 | { | |
276 | struct hlist_head *head = nilfs->ns_gc_inodes_h; | |
277 | struct hlist_node *node, *n; | |
278 | struct inode *inode; | |
279 | int loop; | |
280 | ||
281 | for (loop = 0; loop < NILFS_GCINODE_HASH_SIZE; loop++, head++) { | |
282 | hlist_for_each_entry_safe(inode, node, n, head, i_hash) { | |
283 | hlist_del_init(&inode->i_hash); | |
284 | list_del_init(&NILFS_I(inode)->i_dirty); | |
285 | nilfs_clear_gcinode(inode); /* might sleep */ | |
286 | } | |
287 | } | |
288 | } |