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