1 /* 2 * btnode.c - NILFS B-tree node cache 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 * This file was originally written by Seiji Kihara <kihara@osrg.net> 21 * and fully revised by Ryusuke Konishi <ryusuke@osrg.net> for 22 * stabilization and simplification. 23 * 24 */ 25 26 #include <linux/types.h> 27 #include <linux/buffer_head.h> 28 #include <linux/mm.h> 29 #include <linux/backing-dev.h> 30 #include "nilfs.h" 31 #include "mdt.h" 32 #include "dat.h" 33 #include "page.h" 34 #include "btnode.h" 35 36 37 void nilfs_btnode_cache_init_once(struct address_space *btnc) 38 { 39 memset(btnc, 0, sizeof(*btnc)); 40 INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC); 41 spin_lock_init(&btnc->tree_lock); 42 INIT_LIST_HEAD(&btnc->private_list); 43 spin_lock_init(&btnc->private_lock); 44 45 spin_lock_init(&btnc->i_mmap_lock); 46 INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap); 47 INIT_LIST_HEAD(&btnc->i_mmap_nonlinear); 48 } 49 50 static const struct address_space_operations def_btnode_aops = { 51 .sync_page = block_sync_page, 52 }; 53 54 void nilfs_btnode_cache_init(struct address_space *btnc, 55 struct backing_dev_info *bdi) 56 { 57 btnc->host = NULL; /* can safely set to host inode ? */ 58 btnc->flags = 0; 59 mapping_set_gfp_mask(btnc, GFP_NOFS); 60 btnc->assoc_mapping = NULL; 61 btnc->backing_dev_info = bdi; 62 btnc->a_ops = &def_btnode_aops; 63 } 64 65 void nilfs_btnode_cache_clear(struct address_space *btnc) 66 { 67 invalidate_mapping_pages(btnc, 0, -1); 68 truncate_inode_pages(btnc, 0); 69 } 70 71 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr, 72 sector_t pblocknr, struct buffer_head **pbh, 73 int newblk) 74 { 75 struct buffer_head *bh; 76 struct inode *inode = NILFS_BTNC_I(btnc); 77 int err; 78 79 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node); 80 if (unlikely(!bh)) 81 return -ENOMEM; 82 83 err = -EEXIST; /* internal code */ 84 if (newblk) { 85 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) || 86 buffer_dirty(bh))) { 87 brelse(bh); 88 BUG(); 89 } 90 memset(bh->b_data, 0, 1 << inode->i_blkbits); 91 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; 92 bh->b_blocknr = blocknr; 93 set_buffer_mapped(bh); 94 set_buffer_uptodate(bh); 95 goto found; 96 } 97 98 if (buffer_uptodate(bh) || buffer_dirty(bh)) 99 goto found; 100 101 if (pblocknr == 0) { 102 pblocknr = blocknr; 103 if (inode->i_ino != NILFS_DAT_INO) { 104 struct inode *dat = 105 nilfs_dat_inode(NILFS_I_NILFS(inode)); 106 107 /* blocknr is a virtual block number */ 108 err = nilfs_dat_translate(dat, blocknr, &pblocknr); 109 if (unlikely(err)) { 110 brelse(bh); 111 goto out_locked; 112 } 113 } 114 } 115 lock_buffer(bh); 116 if (buffer_uptodate(bh)) { 117 unlock_buffer(bh); 118 err = -EEXIST; /* internal code */ 119 goto found; 120 } 121 set_buffer_mapped(bh); 122 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; 123 bh->b_blocknr = pblocknr; /* set block address for read */ 124 bh->b_end_io = end_buffer_read_sync; 125 get_bh(bh); 126 submit_bh(READ, bh); 127 bh->b_blocknr = blocknr; /* set back to the given block address */ 128 err = 0; 129 found: 130 *pbh = bh; 131 132 out_locked: 133 unlock_page(bh->b_page); 134 page_cache_release(bh->b_page); 135 return err; 136 } 137 138 int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr, 139 sector_t pblocknr, struct buffer_head **pbh, int newblk) 140 { 141 struct buffer_head *bh; 142 int err; 143 144 err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk); 145 if (err == -EEXIST) /* internal code (cache hit) */ 146 return 0; 147 if (unlikely(err)) 148 return err; 149 150 bh = *pbh; 151 wait_on_buffer(bh); 152 if (!buffer_uptodate(bh)) { 153 brelse(bh); 154 return -EIO; 155 } 156 return 0; 157 } 158 159 /** 160 * nilfs_btnode_delete - delete B-tree node buffer 161 * @bh: buffer to be deleted 162 * 163 * nilfs_btnode_delete() invalidates the specified buffer and delete the page 164 * including the buffer if the page gets unbusy. 165 */ 166 void nilfs_btnode_delete(struct buffer_head *bh) 167 { 168 struct address_space *mapping; 169 struct page *page = bh->b_page; 170 pgoff_t index = page_index(page); 171 int still_dirty; 172 173 page_cache_get(page); 174 lock_page(page); 175 wait_on_page_writeback(page); 176 177 nilfs_forget_buffer(bh); 178 still_dirty = PageDirty(page); 179 mapping = page->mapping; 180 unlock_page(page); 181 page_cache_release(page); 182 183 if (!still_dirty && mapping) 184 invalidate_inode_pages2_range(mapping, index, index); 185 } 186 187 /** 188 * nilfs_btnode_prepare_change_key 189 * prepare to move contents of the block for old key to one of new key. 190 * the old buffer will not be removed, but might be reused for new buffer. 191 * it might return -ENOMEM because of memory allocation errors, 192 * and might return -EIO because of disk read errors. 193 */ 194 int nilfs_btnode_prepare_change_key(struct address_space *btnc, 195 struct nilfs_btnode_chkey_ctxt *ctxt) 196 { 197 struct buffer_head *obh, *nbh; 198 struct inode *inode = NILFS_BTNC_I(btnc); 199 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 200 int err; 201 202 if (oldkey == newkey) 203 return 0; 204 205 obh = ctxt->bh; 206 ctxt->newbh = NULL; 207 208 if (inode->i_blkbits == PAGE_CACHE_SHIFT) { 209 lock_page(obh->b_page); 210 /* 211 * We cannot call radix_tree_preload for the kernels older 212 * than 2.6.23, because it is not exported for modules. 213 */ 214 retry: 215 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); 216 if (err) 217 goto failed_unlock; 218 /* BUG_ON(oldkey != obh->b_page->index); */ 219 if (unlikely(oldkey != obh->b_page->index)) 220 NILFS_PAGE_BUG(obh->b_page, 221 "invalid oldkey %lld (newkey=%lld)", 222 (unsigned long long)oldkey, 223 (unsigned long long)newkey); 224 225 spin_lock_irq(&btnc->tree_lock); 226 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page); 227 spin_unlock_irq(&btnc->tree_lock); 228 /* 229 * Note: page->index will not change to newkey until 230 * nilfs_btnode_commit_change_key() will be called. 231 * To protect the page in intermediate state, the page lock 232 * is held. 233 */ 234 radix_tree_preload_end(); 235 if (!err) 236 return 0; 237 else if (err != -EEXIST) 238 goto failed_unlock; 239 240 err = invalidate_inode_pages2_range(btnc, newkey, newkey); 241 if (!err) 242 goto retry; 243 /* fallback to copy mode */ 244 unlock_page(obh->b_page); 245 } 246 247 err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1); 248 if (likely(!err)) { 249 BUG_ON(nbh == obh); 250 ctxt->newbh = nbh; 251 } 252 return err; 253 254 failed_unlock: 255 unlock_page(obh->b_page); 256 return err; 257 } 258 259 /** 260 * nilfs_btnode_commit_change_key 261 * commit the change_key operation prepared by prepare_change_key(). 262 */ 263 void nilfs_btnode_commit_change_key(struct address_space *btnc, 264 struct nilfs_btnode_chkey_ctxt *ctxt) 265 { 266 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh; 267 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 268 struct page *opage; 269 270 if (oldkey == newkey) 271 return; 272 273 if (nbh == NULL) { /* blocksize == pagesize */ 274 opage = obh->b_page; 275 if (unlikely(oldkey != opage->index)) 276 NILFS_PAGE_BUG(opage, 277 "invalid oldkey %lld (newkey=%lld)", 278 (unsigned long long)oldkey, 279 (unsigned long long)newkey); 280 nilfs_btnode_mark_dirty(obh); 281 282 spin_lock_irq(&btnc->tree_lock); 283 radix_tree_delete(&btnc->page_tree, oldkey); 284 radix_tree_tag_set(&btnc->page_tree, newkey, 285 PAGECACHE_TAG_DIRTY); 286 spin_unlock_irq(&btnc->tree_lock); 287 288 opage->index = obh->b_blocknr = newkey; 289 unlock_page(opage); 290 } else { 291 nilfs_copy_buffer(nbh, obh); 292 nilfs_btnode_mark_dirty(nbh); 293 294 nbh->b_blocknr = newkey; 295 ctxt->bh = nbh; 296 nilfs_btnode_delete(obh); /* will decrement bh->b_count */ 297 } 298 } 299 300 /** 301 * nilfs_btnode_abort_change_key 302 * abort the change_key operation prepared by prepare_change_key(). 303 */ 304 void nilfs_btnode_abort_change_key(struct address_space *btnc, 305 struct nilfs_btnode_chkey_ctxt *ctxt) 306 { 307 struct buffer_head *nbh = ctxt->newbh; 308 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 309 310 if (oldkey == newkey) 311 return; 312 313 if (nbh == NULL) { /* blocksize == pagesize */ 314 spin_lock_irq(&btnc->tree_lock); 315 radix_tree_delete(&btnc->page_tree, newkey); 316 spin_unlock_irq(&btnc->tree_lock); 317 unlock_page(ctxt->bh->b_page); 318 } else 319 brelse(nbh); 320 } 321