1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * NILFS B-tree node cache 4 * 5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. 6 * 7 * Originally written by Seiji Kihara. 8 * Fully revised by Ryusuke Konishi for stabilization and simplification. 9 * 10 */ 11 12 #include <linux/types.h> 13 #include <linux/buffer_head.h> 14 #include <linux/mm.h> 15 #include <linux/backing-dev.h> 16 #include <linux/gfp.h> 17 #include "nilfs.h" 18 #include "mdt.h" 19 #include "dat.h" 20 #include "page.h" 21 #include "btnode.h" 22 23 24 /** 25 * nilfs_init_btnc_inode - initialize B-tree node cache inode 26 * @btnc_inode: inode to be initialized 27 * 28 * nilfs_init_btnc_inode() sets up an inode for B-tree node cache. 29 */ 30 void nilfs_init_btnc_inode(struct inode *btnc_inode) 31 { 32 struct nilfs_inode_info *ii = NILFS_I(btnc_inode); 33 34 btnc_inode->i_mode = S_IFREG; 35 ii->i_flags = 0; 36 memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap)); 37 mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS); 38 } 39 40 void nilfs_btnode_cache_clear(struct address_space *btnc) 41 { 42 invalidate_mapping_pages(btnc, 0, -1); 43 truncate_inode_pages(btnc, 0); 44 } 45 46 struct buffer_head * 47 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr) 48 { 49 struct inode *inode = btnc->host; 50 struct buffer_head *bh; 51 52 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); 53 if (unlikely(!bh)) 54 return NULL; 55 56 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) || 57 buffer_dirty(bh))) { 58 brelse(bh); 59 BUG(); 60 } 61 memset(bh->b_data, 0, i_blocksize(inode)); 62 bh->b_bdev = inode->i_sb->s_bdev; 63 bh->b_blocknr = blocknr; 64 set_buffer_mapped(bh); 65 set_buffer_uptodate(bh); 66 67 unlock_page(bh->b_page); 68 put_page(bh->b_page); 69 return bh; 70 } 71 72 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr, 73 sector_t pblocknr, blk_opf_t opf, 74 struct buffer_head **pbh, sector_t *submit_ptr) 75 { 76 struct buffer_head *bh; 77 struct inode *inode = btnc->host; 78 struct page *page; 79 int err; 80 81 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); 82 if (unlikely(!bh)) 83 return -ENOMEM; 84 85 err = -EEXIST; /* internal code */ 86 page = bh->b_page; 87 88 if (buffer_uptodate(bh) || buffer_dirty(bh)) 89 goto found; 90 91 if (pblocknr == 0) { 92 pblocknr = blocknr; 93 if (inode->i_ino != NILFS_DAT_INO) { 94 struct the_nilfs *nilfs = inode->i_sb->s_fs_info; 95 96 /* blocknr is a virtual block number */ 97 err = nilfs_dat_translate(nilfs->ns_dat, blocknr, 98 &pblocknr); 99 if (unlikely(err)) { 100 brelse(bh); 101 goto out_locked; 102 } 103 } 104 } 105 106 if (opf & REQ_RAHEAD) { 107 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) { 108 err = -EBUSY; /* internal code */ 109 brelse(bh); 110 goto out_locked; 111 } 112 } else { /* opf == REQ_OP_READ */ 113 lock_buffer(bh); 114 } 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 = inode->i_sb->s_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(opf, bh); 126 bh->b_blocknr = blocknr; /* set back to the given block address */ 127 *submit_ptr = pblocknr; 128 err = 0; 129 found: 130 *pbh = bh; 131 132 out_locked: 133 unlock_page(page); 134 put_page(page); 135 return err; 136 } 137 138 /** 139 * nilfs_btnode_delete - delete B-tree node buffer 140 * @bh: buffer to be deleted 141 * 142 * nilfs_btnode_delete() invalidates the specified buffer and delete the page 143 * including the buffer if the page gets unbusy. 144 */ 145 void nilfs_btnode_delete(struct buffer_head *bh) 146 { 147 struct address_space *mapping; 148 struct page *page = bh->b_page; 149 pgoff_t index = page_index(page); 150 int still_dirty; 151 152 get_page(page); 153 lock_page(page); 154 wait_on_page_writeback(page); 155 156 nilfs_forget_buffer(bh); 157 still_dirty = PageDirty(page); 158 mapping = page->mapping; 159 unlock_page(page); 160 put_page(page); 161 162 if (!still_dirty && mapping) 163 invalidate_inode_pages2_range(mapping, index, index); 164 } 165 166 /** 167 * nilfs_btnode_prepare_change_key 168 * prepare to move contents of the block for old key to one of new key. 169 * the old buffer will not be removed, but might be reused for new buffer. 170 * it might return -ENOMEM because of memory allocation errors, 171 * and might return -EIO because of disk read errors. 172 */ 173 int nilfs_btnode_prepare_change_key(struct address_space *btnc, 174 struct nilfs_btnode_chkey_ctxt *ctxt) 175 { 176 struct buffer_head *obh, *nbh; 177 struct inode *inode = btnc->host; 178 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 179 int err; 180 181 if (oldkey == newkey) 182 return 0; 183 184 obh = ctxt->bh; 185 ctxt->newbh = NULL; 186 187 if (inode->i_blkbits == PAGE_SHIFT) { 188 struct page *opage = obh->b_page; 189 lock_page(opage); 190 retry: 191 /* BUG_ON(oldkey != obh->b_folio->index); */ 192 if (unlikely(oldkey != opage->index)) 193 NILFS_PAGE_BUG(opage, 194 "invalid oldkey %lld (newkey=%lld)", 195 (unsigned long long)oldkey, 196 (unsigned long long)newkey); 197 198 xa_lock_irq(&btnc->i_pages); 199 err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS); 200 xa_unlock_irq(&btnc->i_pages); 201 /* 202 * Note: page->index will not change to newkey until 203 * nilfs_btnode_commit_change_key() will be called. 204 * To protect the page in intermediate state, the page lock 205 * is held. 206 */ 207 if (!err) 208 return 0; 209 else if (err != -EBUSY) 210 goto failed_unlock; 211 212 err = invalidate_inode_pages2_range(btnc, newkey, newkey); 213 if (!err) 214 goto retry; 215 /* fallback to copy mode */ 216 unlock_page(opage); 217 } 218 219 nbh = nilfs_btnode_create_block(btnc, newkey); 220 if (!nbh) 221 return -ENOMEM; 222 223 BUG_ON(nbh == obh); 224 ctxt->newbh = nbh; 225 return 0; 226 227 failed_unlock: 228 unlock_page(obh->b_page); 229 return err; 230 } 231 232 /** 233 * nilfs_btnode_commit_change_key 234 * commit the change_key operation prepared by prepare_change_key(). 235 */ 236 void nilfs_btnode_commit_change_key(struct address_space *btnc, 237 struct nilfs_btnode_chkey_ctxt *ctxt) 238 { 239 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh; 240 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 241 struct page *opage; 242 243 if (oldkey == newkey) 244 return; 245 246 if (nbh == NULL) { /* blocksize == pagesize */ 247 opage = obh->b_page; 248 if (unlikely(oldkey != opage->index)) 249 NILFS_PAGE_BUG(opage, 250 "invalid oldkey %lld (newkey=%lld)", 251 (unsigned long long)oldkey, 252 (unsigned long long)newkey); 253 mark_buffer_dirty(obh); 254 255 xa_lock_irq(&btnc->i_pages); 256 __xa_erase(&btnc->i_pages, oldkey); 257 __xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY); 258 xa_unlock_irq(&btnc->i_pages); 259 260 opage->index = obh->b_blocknr = newkey; 261 unlock_page(opage); 262 } else { 263 nilfs_copy_buffer(nbh, obh); 264 mark_buffer_dirty(nbh); 265 266 nbh->b_blocknr = newkey; 267 ctxt->bh = nbh; 268 nilfs_btnode_delete(obh); /* will decrement bh->b_count */ 269 } 270 } 271 272 /** 273 * nilfs_btnode_abort_change_key 274 * abort the change_key operation prepared by prepare_change_key(). 275 */ 276 void nilfs_btnode_abort_change_key(struct address_space *btnc, 277 struct nilfs_btnode_chkey_ctxt *ctxt) 278 { 279 struct buffer_head *nbh = ctxt->newbh; 280 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 281 282 if (oldkey == newkey) 283 return; 284 285 if (nbh == NULL) { /* blocksize == pagesize */ 286 xa_erase_irq(&btnc->i_pages, newkey); 287 unlock_page(ctxt->bh->b_page); 288 } else { 289 /* 290 * When canceling a buffer that a prepare operation has 291 * allocated to copy a node block to another location, use 292 * nilfs_btnode_delete() to initialize and release the buffer 293 * so that the buffer flags will not be in an inconsistent 294 * state when it is reallocated. 295 */ 296 nilfs_btnode_delete(nbh); 297 } 298 } 299