Ryusuke Konishi | a3d93f7 | 2009-04-06 19:01:40 -0700 | [diff] [blame] | 1 | /* |
Ryusuke Konishi | 047180f | 2009-04-06 19:01:45 -0700 | [diff] [blame] | 2 | * gcinode.c - dummy inodes to buffer blocks for garbage collection |
Ryusuke Konishi | a3d93f7 | 2009-04-06 19:01:40 -0700 | [diff] [blame] | 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 | */ |
Ryusuke Konishi | 047180f | 2009-04-06 19:01:45 -0700 | [diff] [blame] | 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 | */ |
Ryusuke Konishi | a3d93f7 | 2009-04-06 19:01:40 -0700 | [diff] [blame] | 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; |
| 229 | ii->i_dtime = 0; |
| 230 | nilfs_bmap_init_gc(ii->i_bmap); |
| 231 | |
| 232 | return inode; |
| 233 | } |
| 234 | |
| 235 | static unsigned long ihash(ino_t ino, __u64 cno) |
| 236 | { |
| 237 | return hash_long((unsigned long)((ino << 2) + cno), |
| 238 | NILFS_GCINODE_HASH_BITS); |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * nilfs_gc_iget() - find or create gc inode with specified (ino,cno) |
| 243 | */ |
| 244 | struct inode *nilfs_gc_iget(struct the_nilfs *nilfs, ino_t ino, __u64 cno) |
| 245 | { |
| 246 | struct hlist_head *head = nilfs->ns_gc_inodes_h + ihash(ino, cno); |
| 247 | struct hlist_node *node; |
| 248 | struct inode *inode; |
| 249 | |
| 250 | hlist_for_each_entry(inode, node, head, i_hash) { |
| 251 | if (inode->i_ino == ino && NILFS_I(inode)->i_cno == cno) |
| 252 | return inode; |
| 253 | } |
| 254 | |
| 255 | inode = alloc_gcinode(nilfs, ino, cno); |
| 256 | if (likely(inode)) { |
| 257 | hlist_add_head(&inode->i_hash, head); |
| 258 | list_add(&NILFS_I(inode)->i_dirty, &nilfs->ns_gc_inodes); |
| 259 | } |
| 260 | return inode; |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * nilfs_clear_gcinode() - clear and free a gc inode |
| 265 | */ |
| 266 | void nilfs_clear_gcinode(struct inode *inode) |
| 267 | { |
| 268 | nilfs_mdt_clear(inode); |
| 269 | nilfs_mdt_destroy(inode); |
| 270 | } |
| 271 | |
| 272 | /* |
| 273 | * nilfs_remove_all_gcinode() - remove all inodes from the_nilfs |
| 274 | */ |
| 275 | void nilfs_remove_all_gcinode(struct the_nilfs *nilfs) |
| 276 | { |
| 277 | struct hlist_head *head = nilfs->ns_gc_inodes_h; |
| 278 | struct hlist_node *node, *n; |
| 279 | struct inode *inode; |
| 280 | int loop; |
| 281 | |
| 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 */ |
| 287 | } |
| 288 | } |
| 289 | } |