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 "reiserfs.h"
  17 #include <linux/buffer_head.h>
  18
  19 int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
  20 {
  21         int err = 0;
  22         struct reiserfs_super_block *sb;
  23         struct reiserfs_bitmap_info *bitmap;
  24         struct reiserfs_bitmap_info *info;
  25         struct reiserfs_bitmap_info *old_bitmap = SB_AP_BITMAP(s);
  26         struct buffer_head *bh;
  27         struct reiserfs_transaction_handle th;
  28         unsigned int bmap_nr_new, bmap_nr;
  29         unsigned int block_r_new, block_r;
  30
  31         struct reiserfs_list_bitmap *jb;
  32         struct reiserfs_list_bitmap jbitmap[JOURNAL_NUM_BITMAPS];
  33
  34         unsigned long int block_count, free_blocks;
  35         int i;
  36         int copy_size;
  37         int depth;
  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         depth = reiserfs_write_unlock_nested(s);
  48         bh = sb_bread(s, block_count_new - 1);
  49         reiserfs_write_lock_nested(s, depth);
  50         if (!bh) {
  51                 printk("reiserfs_resize: can\'t read last block\n");
  52                 return -EINVAL;
  53         }
  54         bforget(bh);
  55
  56         /* old disk layout detection; those partitions can be mounted, but
  57          * cannot be resized */
  58         if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
  59             != REISERFS_DISK_OFFSET_IN_BYTES) {
  60                 printk
  61                     ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
  62                 return -ENOTSUPP;
  63         }
  64
  65         /* count used bits in last bitmap block */
  66         block_r = SB_BLOCK_COUNT(s) -
  67                         (reiserfs_bmap_count(s) - 1) * s->s_blocksize * 8;
  68
  69         /* count bitmap blocks in new fs */
  70         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
  71         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  72         if (block_r_new)
  73                 bmap_nr_new++;
  74         else
  75                 block_r_new = s->s_blocksize * 8;
  76
  77         /* save old values */
  78         block_count = SB_BLOCK_COUNT(s);
  79         bmap_nr = reiserfs_bmap_count(s);
  80
  81         /* resizing of reiserfs bitmaps (journal and real), if needed */
  82         if (bmap_nr_new > bmap_nr) {
  83                 /* reallocate journal bitmaps */
  84                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  85                         printk
  86                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  87                         return -ENOMEM;
  88                 }
  89                 /* the new journal bitmaps are zero filled, now we copy in the bitmap
  90                  ** node pointers from the old journal bitmap structs, and then
  91                  ** transfer the new data structures into the journal struct.
  92                  **
  93                  ** using the copy_size var below allows this code to work for
  94                  ** both shrinking and expanding the FS.
  95                  */
  96                 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
  97                 copy_size =
  98                     copy_size * sizeof(struct reiserfs_list_bitmap_node *);
  99                 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
 100                         struct reiserfs_bitmap_node **node_tmp;
 101                         jb = SB_JOURNAL(s)->j_list_bitmap + i;
 102                         memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
 103
 104                         /* just in case vfree schedules on us, copy the new
 105                          ** pointer into the journal struct before freeing the
 106                          ** old one
 107                          */
 108                         node_tmp = jb->bitmaps;
 109                         jb->bitmaps = jbitmap[i].bitmaps;
 110                         vfree(node_tmp);
 111                 }
 112
 113                 /* allocate additional bitmap blocks, reallocate array of bitmap
 114                  * block pointers */
 115                 bitmap =
 116                     vzalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
 117                 if (!bitmap) {
 118                         /* Journal bitmaps are still supersized, but the memory isn't
 119                          * leaked, so I guess it's ok */
 120                         printk("reiserfs_resize: unable to allocate memory.\n");
 121                         return -ENOMEM;
 122                 }
 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                         int depth;
 132                         /* don't use read_bitmap_block since it will cache
 133                          * the uninitialized bitmap */
 134                         depth = reiserfs_write_unlock_nested(s);
 135                         bh = sb_bread(s, i * s->s_blocksize * 8);
 136                         reiserfs_write_lock_nested(s, depth);
 137                         if (!bh) {
 138                                 vfree(bitmap);
 139                                 return -EIO;
 140                         }
 141                         memset(bh->b_data, 0, sb_blocksize(sb));
 142                         reiserfs_set_le_bit(0, bh->b_data);
 143                         reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
 144
 145                         set_buffer_uptodate(bh);
 146                         mark_buffer_dirty(bh);
 147                         depth = reiserfs_write_unlock_nested(s);
 148                         sync_dirty_buffer(bh);
 149                         reiserfs_write_lock_nested(s, depth);
 150                         // update bitmap_info stuff
 151                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 152                         brelse(bh);
 153                 }
 154                 /* free old bitmap blocks array */
 155                 SB_AP_BITMAP(s) = bitmap;
 156                 vfree(old_bitmap);
 157         }
 158
 159         /* begin transaction, if there was an error, it's fine. Yes, we have
 160          * incorrect bitmaps now, but none of it is ever going to touch the
 161          * disk anyway. */
 162         err = journal_begin(&th, s, 10);
 163         if (err)
 164                 return err;
 165
 166         /* Extend old last bitmap block - new blocks have been made available */
 167         info = SB_AP_BITMAP(s) + bmap_nr - 1;
 168         bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
 169         if (!bh) {
 170                 int jerr = journal_end(&th, s, 10);
 171                 if (jerr)
 172                         return jerr;
 173                 return -EIO;
 174         }
 175
 176         reiserfs_prepare_for_journal(s, bh, 1);
 177         for (i = block_r; i < s->s_blocksize * 8; i++)
 178                 reiserfs_clear_le_bit(i, bh->b_data);
 179         info->free_count += s->s_blocksize * 8 - block_r;
 180
 181         journal_mark_dirty(&th, s, bh);
 182         brelse(bh);
 183
 184         /* Correct new last bitmap block - It may not be full */
 185         info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
 186         bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
 187         if (!bh) {
 188                 int jerr = journal_end(&th, s, 10);
 189                 if (jerr)
 190                         return jerr;
 191                 return -EIO;
 192         }
 193
 194         reiserfs_prepare_for_journal(s, bh, 1);
 195         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 196                 reiserfs_set_le_bit(i, bh->b_data);
 197         journal_mark_dirty(&th, s, bh);
 198         brelse(bh);
 199
 200         info->free_count -= s->s_blocksize * 8 - block_r_new;
 201         /* update super */
 202         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 203         free_blocks = SB_FREE_BLOCKS(s);
 204         PUT_SB_FREE_BLOCKS(s,
 205                            free_blocks + (block_count_new - block_count -
 206                                           (bmap_nr_new - bmap_nr)));
 207         PUT_SB_BLOCK_COUNT(s, block_count_new);
 208         PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
 209
 210         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 211
 212         SB_JOURNAL(s)->j_must_wait = 1;
 213         return journal_end(&th, s, 10);
 214 }