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 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; 91 bh->b_blocknr = blocknr; 92 set_buffer_mapped(bh); 93 set_buffer_uptodate(bh); 94 goto found; 95 } 96 97 if (buffer_uptodate(bh) || buffer_dirty(bh)) 98 goto found; 99 100 if (pblocknr == 0) { 101 pblocknr = blocknr; 102 if (inode->i_ino != NILFS_DAT_INO) { 103 struct inode *dat = 104 nilfs_dat_inode(NILFS_I_NILFS(inode)); 105 106 /* blocknr is a virtual block number */ 107 err = nilfs_dat_translate(dat, blocknr, &pblocknr); 108 if (unlikely(err)) { 109 brelse(bh); 110 goto out_locked; 111 } 112 } 113 } 114 lock_buffer(bh); 115 if (buffer_uptodate(bh)) { 116 unlock_buffer(bh); 117 err = -EEXIST; /* internal code */ 118 goto found; 119 } 120 set_buffer_mapped(bh); 121 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev; 122 bh->b_blocknr = pblocknr; /* set block address for read */ 123 bh->b_end_io = end_buffer_read_sync; 124 get_bh(bh); 125 submit_bh(READ, bh); 126 bh->b_blocknr = blocknr; /* set back to the given block address */ 127 err = 0; 128 found: 129 *pbh = bh; 130 131 out_locked: 132 unlock_page(bh->b_page); 133 page_cache_release(bh->b_page); 134 return err; 135 } 136 137 int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr, 138 sector_t pblocknr, struct buffer_head **pbh, int newblk) 139 { 140 struct buffer_head *bh; 141 int err; 142 143 err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk); 144 if (err == -EEXIST) /* internal code (cache hit) */ 145 return 0; 146 if (unlikely(err)) 147 return err; 148 149 bh = *pbh; 150 wait_on_buffer(bh); 151 if (!buffer_uptodate(bh)) { 152 brelse(bh); 153 return -EIO; 154 } 155 return 0; 156 } 157 158 /** 159 * nilfs_btnode_delete - delete B-tree node buffer 160 * @bh: buffer to be deleted 161 * 162 * nilfs_btnode_delete() invalidates the specified buffer and delete the page 163 * including the buffer if the page gets unbusy. 164 */ 165 void nilfs_btnode_delete(struct buffer_head *bh) 166 { 167 struct address_space *mapping; 168 struct page *page = bh->b_page; 169 pgoff_t index = page_index(page); 170 int still_dirty; 171 172 page_cache_get(page); 173 lock_page(page); 174 wait_on_page_writeback(page); 175 176 nilfs_forget_buffer(bh); 177 still_dirty = PageDirty(page); 178 mapping = page->mapping; 179 unlock_page(page); 180 page_cache_release(page); 181 182 if (!still_dirty && mapping) 183 invalidate_inode_pages2_range(mapping, index, index); 184 } 185 186 /** 187 * nilfs_btnode_prepare_change_key 188 * prepare to move contents of the block for old key to one of new key. 189 * the old buffer will not be removed, but might be reused for new buffer. 190 * it might return -ENOMEM because of memory allocation errors, 191 * and might return -EIO because of disk read errors. 192 */ 193 int nilfs_btnode_prepare_change_key(struct address_space *btnc, 194 struct nilfs_btnode_chkey_ctxt *ctxt) 195 { 196 struct buffer_head *obh, *nbh; 197 struct inode *inode = NILFS_BTNC_I(btnc); 198 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 199 int err; 200 201 if (oldkey == newkey) 202 return 0; 203 204 obh = ctxt->bh; 205 ctxt->newbh = NULL; 206 207 if (inode->i_blkbits == PAGE_CACHE_SHIFT) { 208 lock_page(obh->b_page); 209 /* 210 * We cannot call radix_tree_preload for the kernels older 211 * than 2.6.23, because it is not exported for modules. 212 */ 213 retry: 214 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); 215 if (err) 216 goto failed_unlock; 217 /* BUG_ON(oldkey != obh->b_page->index); */ 218 if (unlikely(oldkey != obh->b_page->index)) 219 NILFS_PAGE_BUG(obh->b_page, 220 "invalid oldkey %lld (newkey=%lld)", 221 (unsigned long long)oldkey, 222 (unsigned long long)newkey); 223 224 spin_lock_irq(&btnc->tree_lock); 225 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page); 226 spin_unlock_irq(&btnc->tree_lock); 227 /* 228 * Note: page->index will not change to newkey until 229 * nilfs_btnode_commit_change_key() will be called. 230 * To protect the page in intermediate state, the page lock 231 * is held. 232 */ 233 radix_tree_preload_end(); 234 if (!err) 235 return 0; 236 else if (err != -EEXIST) 237 goto failed_unlock; 238 239 err = invalidate_inode_pages2_range(btnc, newkey, newkey); 240 if (!err) 241 goto retry; 242 /* fallback to copy mode */ 243 unlock_page(obh->b_page); 244 } 245 246 err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1); 247 if (likely(!err)) { 248 BUG_ON(nbh == obh); 249 ctxt->newbh = nbh; 250 } 251 return err; 252 253 failed_unlock: 254 unlock_page(obh->b_page); 255 return err; 256 } 257 258 /** 259 * nilfs_btnode_commit_change_key 260 * commit the change_key operation prepared by prepare_change_key(). 261 */ 262 void nilfs_btnode_commit_change_key(struct address_space *btnc, 263 struct nilfs_btnode_chkey_ctxt *ctxt) 264 { 265 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh; 266 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 267 struct page *opage; 268 269 if (oldkey == newkey) 270 return; 271 272 if (nbh == NULL) { /* blocksize == pagesize */ 273 opage = obh->b_page; 274 if (unlikely(oldkey != opage->index)) 275 NILFS_PAGE_BUG(opage, 276 "invalid oldkey %lld (newkey=%lld)", 277 (unsigned long long)oldkey, 278 (unsigned long long)newkey); 279 if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage)) 280 BUG(); 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