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