fs/nilfs2/btnode.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * btnode.c - 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 }