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 void nilfs_btnode_cache_clear(struct address_space *btnc) 24 { 25 invalidate_mapping_pages(btnc, 0, -1); 26 truncate_inode_pages(btnc, 0); 27 } 28 29 struct buffer_head * 30 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr) 31 { 32 struct inode *inode = NILFS_BTNC_I(btnc); 33 struct buffer_head *bh; 34 35 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); 36 if (unlikely(!bh)) 37 return NULL; 38 39 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) || 40 buffer_dirty(bh))) { 41 brelse(bh); 42 BUG(); 43 } 44 memset(bh->b_data, 0, i_blocksize(inode)); 45 bh->b_bdev = inode->i_sb->s_bdev; 46 bh->b_blocknr = blocknr; 47 set_buffer_mapped(bh); 48 set_buffer_uptodate(bh); 49 50 unlock_page(bh->b_page); 51 put_page(bh->b_page); 52 return bh; 53 } 54 55 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr, 56 sector_t pblocknr, int mode, int mode_flags, 57 struct buffer_head **pbh, sector_t *submit_ptr) 58 { 59 struct buffer_head *bh; 60 struct inode *inode = NILFS_BTNC_I(btnc); 61 struct page *page; 62 int err; 63 64 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); 65 if (unlikely(!bh)) 66 return -ENOMEM; 67 68 err = -EEXIST; /* internal code */ 69 page = bh->b_page; 70 71 if (buffer_uptodate(bh) || buffer_dirty(bh)) 72 goto found; 73 74 if (pblocknr == 0) { 75 pblocknr = blocknr; 76 if (inode->i_ino != NILFS_DAT_INO) { 77 struct the_nilfs *nilfs = inode->i_sb->s_fs_info; 78 79 /* blocknr is a virtual block number */ 80 err = nilfs_dat_translate(nilfs->ns_dat, blocknr, 81 &pblocknr); 82 if (unlikely(err)) { 83 brelse(bh); 84 goto out_locked; 85 } 86 } 87 } 88 89 if (mode_flags & REQ_RAHEAD) { 90 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) { 91 err = -EBUSY; /* internal code */ 92 brelse(bh); 93 goto out_locked; 94 } 95 } else { /* mode == READ */ 96 lock_buffer(bh); 97 } 98 if (buffer_uptodate(bh)) { 99 unlock_buffer(bh); 100 err = -EEXIST; /* internal code */ 101 goto found; 102 } 103 set_buffer_mapped(bh); 104 bh->b_bdev = inode->i_sb->s_bdev; 105 bh->b_blocknr = pblocknr; /* set block address for read */ 106 bh->b_end_io = end_buffer_read_sync; 107 get_bh(bh); 108 submit_bh(mode, mode_flags, bh); 109 bh->b_blocknr = blocknr; /* set back to the given block address */ 110 *submit_ptr = pblocknr; 111 err = 0; 112 found: 113 *pbh = bh; 114 115 out_locked: 116 unlock_page(page); 117 put_page(page); 118 return err; 119 } 120 121 /** 122 * nilfs_btnode_delete - delete B-tree node buffer 123 * @bh: buffer to be deleted 124 * 125 * nilfs_btnode_delete() invalidates the specified buffer and delete the page 126 * including the buffer if the page gets unbusy. 127 */ 128 void nilfs_btnode_delete(struct buffer_head *bh) 129 { 130 struct address_space *mapping; 131 struct page *page = bh->b_page; 132 pgoff_t index = page_index(page); 133 int still_dirty; 134 135 get_page(page); 136 lock_page(page); 137 wait_on_page_writeback(page); 138 139 nilfs_forget_buffer(bh); 140 still_dirty = PageDirty(page); 141 mapping = page->mapping; 142 unlock_page(page); 143 put_page(page); 144 145 if (!still_dirty && mapping) 146 invalidate_inode_pages2_range(mapping, index, index); 147 } 148 149 /** 150 * nilfs_btnode_prepare_change_key 151 * prepare to move contents of the block for old key to one of new key. 152 * the old buffer will not be removed, but might be reused for new buffer. 153 * it might return -ENOMEM because of memory allocation errors, 154 * and might return -EIO because of disk read errors. 155 */ 156 int nilfs_btnode_prepare_change_key(struct address_space *btnc, 157 struct nilfs_btnode_chkey_ctxt *ctxt) 158 { 159 struct buffer_head *obh, *nbh; 160 struct inode *inode = NILFS_BTNC_I(btnc); 161 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 162 int err; 163 164 if (oldkey == newkey) 165 return 0; 166 167 obh = ctxt->bh; 168 ctxt->newbh = NULL; 169 170 if (inode->i_blkbits == PAGE_SHIFT) { 171 struct page *opage = obh->b_page; 172 lock_page(opage); 173 retry: 174 /* BUG_ON(oldkey != obh->b_page->index); */ 175 if (unlikely(oldkey != opage->index)) 176 NILFS_PAGE_BUG(opage, 177 "invalid oldkey %lld (newkey=%lld)", 178 (unsigned long long)oldkey, 179 (unsigned long long)newkey); 180 181 xa_lock_irq(&btnc->i_pages); 182 err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS); 183 xa_unlock_irq(&btnc->i_pages); 184 /* 185 * Note: page->index will not change to newkey until 186 * nilfs_btnode_commit_change_key() will be called. 187 * To protect the page in intermediate state, the page lock 188 * is held. 189 */ 190 if (!err) 191 return 0; 192 else if (err != -EBUSY) 193 goto failed_unlock; 194 195 err = invalidate_inode_pages2_range(btnc, newkey, newkey); 196 if (!err) 197 goto retry; 198 /* fallback to copy mode */ 199 unlock_page(opage); 200 } 201 202 nbh = nilfs_btnode_create_block(btnc, newkey); 203 if (!nbh) 204 return -ENOMEM; 205 206 BUG_ON(nbh == obh); 207 ctxt->newbh = nbh; 208 return 0; 209 210 failed_unlock: 211 unlock_page(obh->b_page); 212 return err; 213 } 214 215 /** 216 * nilfs_btnode_commit_change_key 217 * commit the change_key operation prepared by prepare_change_key(). 218 */ 219 void nilfs_btnode_commit_change_key(struct address_space *btnc, 220 struct nilfs_btnode_chkey_ctxt *ctxt) 221 { 222 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh; 223 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 224 struct page *opage; 225 226 if (oldkey == newkey) 227 return; 228 229 if (nbh == NULL) { /* blocksize == pagesize */ 230 opage = obh->b_page; 231 if (unlikely(oldkey != opage->index)) 232 NILFS_PAGE_BUG(opage, 233 "invalid oldkey %lld (newkey=%lld)", 234 (unsigned long long)oldkey, 235 (unsigned long long)newkey); 236 mark_buffer_dirty(obh); 237 238 xa_lock_irq(&btnc->i_pages); 239 __xa_erase(&btnc->i_pages, oldkey); 240 __xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY); 241 xa_unlock_irq(&btnc->i_pages); 242 243 opage->index = obh->b_blocknr = newkey; 244 unlock_page(opage); 245 } else { 246 nilfs_copy_buffer(nbh, obh); 247 mark_buffer_dirty(nbh); 248 249 nbh->b_blocknr = newkey; 250 ctxt->bh = nbh; 251 nilfs_btnode_delete(obh); /* will decrement bh->b_count */ 252 } 253 } 254 255 /** 256 * nilfs_btnode_abort_change_key 257 * abort the change_key operation prepared by prepare_change_key(). 258 */ 259 void nilfs_btnode_abort_change_key(struct address_space *btnc, 260 struct nilfs_btnode_chkey_ctxt *ctxt) 261 { 262 struct buffer_head *nbh = ctxt->newbh; 263 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; 264 265 if (oldkey == newkey) 266 return; 267 268 if (nbh == NULL) { /* blocksize == pagesize */ 269 xa_erase_irq(&btnc->i_pages, newkey); 270 unlock_page(ctxt->bh->b_page); 271 } else 272 brelse(nbh); 273 } 274