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