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