fs/reiserfs/resize.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 /*
   6  * Written by Alexander Zarochentcev.
   7  *
   8  * The kernel part of the (on-line) reiserfs resizer.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/string.h>
  15 #include <linux/errno.h>
  16 #include <linux/reiserfs_fs.h>
  17 #include <linux/reiserfs_fs_sb.h>
  18 #include <linux/buffer_head.h>
  19
  20 int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
  21 {
  22         int err = 0;
  23         struct reiserfs_super_block *sb;
  24         struct reiserfs_bitmap_info *bitmap;
  25         struct reiserfs_bitmap_info *info;
  26         struct reiserfs_bitmap_info *old_bitmap = SB_AP_BITMAP(s);
  27         struct buffer_head *bh;
  28         struct reiserfs_transaction_handle th;
  29         unsigned int bmap_nr_new, bmap_nr;
  30         unsigned int block_r_new, block_r;
  31
  32         struct reiserfs_list_bitmap *jb;
  33         struct reiserfs_list_bitmap jbitmap[JOURNAL_NUM_BITMAPS];
  34
  35         unsigned long int block_count, free_blocks;
  36         int i;
  37         int copy_size;
  38
  39         sb = SB_DISK_SUPER_BLOCK(s);
  40
  41         if (SB_BLOCK_COUNT(s) >= block_count_new) {
  42                 printk("can\'t shrink filesystem on-line\n");
  43                 return -EINVAL;
  44         }
  45
  46         /* check the device size */
  47         bh = sb_bread(s, block_count_new - 1);
  48         if (!bh) {
  49                 printk("reiserfs_resize: can\'t read last block\n");
  50                 return -EINVAL;
  51         }
  52         bforget(bh);
  53
  54         /* old disk layout detection; those partitions can be mounted, but
  55          * cannot be resized */
  56         if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
  57             != REISERFS_DISK_OFFSET_IN_BYTES) {
  58                 printk
  59                     ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
  60                 return -ENOTSUPP;
  61         }
  62
  63         /* count used bits in last bitmap block */
  64         block_r = SB_BLOCK_COUNT(s) -
  65                         (reiserfs_bmap_count(s) - 1) * s->s_blocksize * 8;
  66
  67         /* count bitmap blocks in new fs */
  68         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
  69         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  70         if (block_r_new)
  71                 bmap_nr_new++;
  72         else
  73                 block_r_new = s->s_blocksize * 8;
  74
  75         /* save old values */
  76         block_count = SB_BLOCK_COUNT(s);
  77         bmap_nr = reiserfs_bmap_count(s);
  78
  79         /* resizing of reiserfs bitmaps (journal and real), if needed */
  80         if (bmap_nr_new > bmap_nr) {
  81                 /* reallocate journal bitmaps */
  82                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  83                         printk
  84                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  85                         return -ENOMEM;
  86                 }
  87                 /* the new journal bitmaps are zero filled, now we copy in the bitmap
  88                  ** node pointers from the old journal bitmap structs, and then
  89                  ** transfer the new data structures into the journal struct.
  90                  **
  91                  ** using the copy_size var below allows this code to work for
  92                  ** both shrinking and expanding the FS.
  93                  */
  94                 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
  95                 copy_size =
  96                     copy_size * sizeof(struct reiserfs_list_bitmap_node *);
  97                 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
  98                         struct reiserfs_bitmap_node **node_tmp;
  99                         jb = SB_JOURNAL(s)->j_list_bitmap + i;
 100                         memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
 101
 102                         /* just in case vfree schedules on us, copy the new
 103                          ** pointer into the journal struct before freeing the
 104                          ** old one
 105                          */
 106                         node_tmp = jb->bitmaps;
 107                         jb->bitmaps = jbitmap[i].bitmaps;
 108                         vfree(node_tmp);
 109                 }
 110
 111                 /* allocate additional bitmap blocks, reallocate array of bitmap
 112                  * block pointers */
 113                 bitmap =
 114                     vzalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
 115                 if (!bitmap) {
 116                         /* Journal bitmaps are still supersized, but the memory isn't
 117                          * leaked, so I guess it's ok */
 118                         printk("reiserfs_resize: unable to allocate memory.\n");
 119                         return -ENOMEM;
 120                 }
 121                 for (i = 0; i < bmap_nr; i++)
 122                         bitmap[i] = old_bitmap[i];
 123
 124                 /* This doesn't go through the journal, but it doesn't have to.
 125                  * The changes are still atomic: We're synced up when the journal
 126                  * transaction begins, and the new bitmaps don't matter if the
 127                  * transaction fails. */
 128                 for (i = bmap_nr; i < bmap_nr_new; i++) {
 129                         /* don't use read_bitmap_block since it will cache
 130                          * the uninitialized bitmap */
 131                         bh = sb_bread(s, i * s->s_blocksize * 8);
 132                         if (!bh) {
 133                                 vfree(bitmap);
 134                                 return -EIO;
 135                         }
 136                         memset(bh->b_data, 0, sb_blocksize(sb));
 137                         reiserfs_set_le_bit(0, bh->b_data);
 138                         reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
 139
 140                         set_buffer_uptodate(bh);
 141                         mark_buffer_dirty(bh);
 142                         reiserfs_write_unlock(s);
 143                         sync_dirty_buffer(bh);
 144                         reiserfs_write_lock(s);
 145                         // update bitmap_info stuff
 146                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 147                         brelse(bh);
 148                 }
 149                 /* free old bitmap blocks array */
 150                 SB_AP_BITMAP(s) = bitmap;
 151                 vfree(old_bitmap);
 152         }
 153
 154         /* begin transaction, if there was an error, it's fine. Yes, we have
 155          * incorrect bitmaps now, but none of it is ever going to touch the
 156          * disk anyway. */
 157         err = journal_begin(&th, s, 10);
 158         if (err)
 159                 return err;
 160
 161         /* Extend old last bitmap block - new blocks have been made available */
 162         info = SB_AP_BITMAP(s) + bmap_nr - 1;
 163         bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
 164         if (!bh) {
 165                 int jerr = journal_end(&th, s, 10);
 166                 if (jerr)
 167                         return jerr;
 168                 return -EIO;
 169         }
 170
 171         reiserfs_prepare_for_journal(s, bh, 1);
 172         for (i = block_r; i < s->s_blocksize * 8; i++)
 173                 reiserfs_clear_le_bit(i, bh->b_data);
 174         info->free_count += s->s_blocksize * 8 - block_r;
 175
 176         journal_mark_dirty(&th, s, bh);
 177         brelse(bh);
 178
 179         /* Correct new last bitmap block - It may not be full */
 180         info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
 181         bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
 182         if (!bh) {
 183                 int jerr = journal_end(&th, s, 10);
 184                 if (jerr)
 185                         return jerr;
 186                 return -EIO;
 187         }
 188
 189         reiserfs_prepare_for_journal(s, bh, 1);
 190         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 191                 reiserfs_set_le_bit(i, bh->b_data);
 192         journal_mark_dirty(&th, s, bh);
 193         brelse(bh);
 194
 195         info->free_count -= s->s_blocksize * 8 - block_r_new;
 196         /* update super */
 197         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 198         free_blocks = SB_FREE_BLOCKS(s);
 199         PUT_SB_FREE_BLOCKS(s,
 200                            free_blocks + (block_count_new - block_count -
 201                                           (bmap_nr_new - bmap_nr)));
 202         PUT_SB_BLOCK_COUNT(s, block_count_new);
 203         PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
 204         s->s_dirt = 1;
 205
 206         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 207
 208         SB_JOURNAL(s)->j_must_wait = 1;
 209         return journal_end(&th, s, 10);
 210 }