git.oblomov.eu Git - linux-2.6/blob - 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) - (SB_BMAP_NR(s) - 1) * s->s_blocksize * 8;
  65
  66         /* count bitmap blocks in new fs */
  67         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
  68         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  69         if (block_r_new)
  70                 bmap_nr_new++;
  71         else
  72                 block_r_new = s->s_blocksize * 8;
  73
  74         /* save old values */
  75         block_count = SB_BLOCK_COUNT(s);
  76         bmap_nr = SB_BMAP_NR(s);
  77
  78         /* resizing of reiserfs bitmaps (journal and real), if needed */
  79         if (bmap_nr_new > bmap_nr) {
  80                 /* reallocate journal bitmaps */
  81                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  82                         printk
  83                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  84                         unlock_super(s);
  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                     vmalloc(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                 memset(bitmap, 0,
 122                        sizeof(struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
 123                 for (i = 0; i < bmap_nr; i++)
 124                         bitmap[i] = old_bitmap[i];
 125
 126                 /* This doesn't go through the journal, but it doesn't have to.
 127                  * The changes are still atomic: We're synced up when the journal
 128                  * transaction begins, and the new bitmaps don't matter if the
 129                  * transaction fails. */
 130                 for (i = bmap_nr; i < bmap_nr_new; i++) {
 131                         /* don't use read_bitmap_block since it will cache
 132                          * the uninitialized bitmap */
 133                         bh = sb_bread(s, i * s->s_blocksize * 8);
 134                         if (!bh) {
 135                                 vfree(bitmap);
 136                                 return -EIO;
 137                         }
 138                         memset(bh->b_data, 0, sb_blocksize(sb));
 139                         reiserfs_test_and_set_le_bit(0, bh->b_data);
 140                         reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
 141
 142                         set_buffer_uptodate(bh);
 143                         mark_buffer_dirty(bh);
 144                         sync_dirty_buffer(bh);
 145                         // update bitmap_info stuff
 146                         bitmap[i].first_zero_hint = 1;
 147                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 148                         brelse(bh);
 149                 }
 150                 /* free old bitmap blocks array */
 151                 SB_AP_BITMAP(s) = bitmap;
 152                 vfree(old_bitmap);
 153         }
 154
 155         /* begin transaction, if there was an error, it's fine. Yes, we have
 156          * incorrect bitmaps now, but none of it is ever going to touch the
 157          * disk anyway. */
 158         err = journal_begin(&th, s, 10);
 159         if (err)
 160                 return err;
 161
 162         /* Extend old last bitmap block - new blocks have been made available */
 163         info = SB_AP_BITMAP(s) + bmap_nr - 1;
 164         bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
 165         if (!bh) {
 166                 int jerr = journal_end(&th, s, 10);
 167                 if (jerr)
 168                         return jerr;
 169                 return -EIO;
 170         }
 171
 172         reiserfs_prepare_for_journal(s, bh, 1);
 173         for (i = block_r; i < s->s_blocksize * 8; i++)
 174                 reiserfs_test_and_clear_le_bit(i, bh->b_data);
 175         info->free_count += s->s_blocksize * 8 - block_r;
 176         if (!info->first_zero_hint)
 177                 info->first_zero_hint = block_r;
 178
 179         journal_mark_dirty(&th, s, bh);
 180         brelse(bh);
 181
 182         /* Correct new last bitmap block - It may not be full */
 183         info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
 184         bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
 185         if (!bh) {
 186                 int jerr = journal_end(&th, s, 10);
 187                 if (jerr)
 188                         return jerr;
 189                 return -EIO;
 190         }
 191
 192         reiserfs_prepare_for_journal(s, bh, 1);
 193         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 194                 reiserfs_test_and_set_le_bit(i, bh->b_data);
 195         journal_mark_dirty(&th, s, bh);
 196         brelse(bh);
 197
 198         info->free_count -= s->s_blocksize * 8 - block_r_new;
 199         /* Extreme case where last bitmap is the only valid block in itself. */
 200         if (!info->free_count)
 201                 info->first_zero_hint = 0;
 202         /* update super */
 203         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 204         free_blocks = SB_FREE_BLOCKS(s);
 205         PUT_SB_FREE_BLOCKS(s,
 206                            free_blocks + (block_count_new - block_count -
 207                                           (bmap_nr_new - bmap_nr)));
 208         PUT_SB_BLOCK_COUNT(s, block_count_new);
 209         PUT_SB_BMAP_NR(s, bmap_nr_new);
 210         s->s_dirt = 1;
 211
 212         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 213
 214         SB_JOURNAL(s)->j_must_wait = 1;
 215         return journal_end(&th, s, 10);
 216 }