kernel/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         /*
  57          * old disk layout detection; those partitions can be mounted, but
  58          * cannot be resized
  59          */
  60         if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
  61             != REISERFS_DISK_OFFSET_IN_BYTES) {
  62                 printk
  63                     ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
  64                 return -ENOTSUPP;
  65         }
  66
  67         /* count used bits in last bitmap block */
  68         block_r = SB_BLOCK_COUNT(s) -
  69                         (reiserfs_bmap_count(s) - 1) * s->s_blocksize * 8;
  70
  71         /* count bitmap blocks in new fs */
  72         bmap_nr_new = block_count_new / (s->s_blocksize * 8);
  73         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  74         if (block_r_new)
  75                 bmap_nr_new++;
  76         else
  77                 block_r_new = s->s_blocksize * 8;
  78
  79         /* save old values */
  80         block_count = SB_BLOCK_COUNT(s);
  81         bmap_nr = reiserfs_bmap_count(s);
  82
  83         /* resizing of reiserfs bitmaps (journal and real), if needed */
  84         if (bmap_nr_new > bmap_nr) {
  85                 /* reallocate journal bitmaps */
  86                 if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  87                         printk
  88                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  89                         return -ENOMEM;
  90                 }
  91                 /*
  92                  * the new journal bitmaps are zero filled, now we copy i
  93                  * the bitmap node pointers from the old journal bitmap
  94                  * structs, and then transfer the new data structures
  95                  * into the journal struct.
  96                  *
  97                  * using the copy_size var below allows this code to work for
  98                  * both shrinking and expanding the FS.
  99                  */
 100                 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
 101                 copy_size =
 102                     copy_size * sizeof(struct reiserfs_list_bitmap_node *);
 103                 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
 104                         struct reiserfs_bitmap_node **node_tmp;
 105                         jb = SB_JOURNAL(s)->j_list_bitmap + i;
 106                         memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
 107
 108                         /*
 109                          * just in case vfree schedules on us, copy the new
 110                          * pointer into the journal struct before freeing the
 111                          * old one
 112                          */
 113                         node_tmp = jb->bitmaps;
 114                         jb->bitmaps = jbitmap[i].bitmaps;
 115                         vfree(node_tmp);
 116                 }
 117
 118                 /*
 119                  * allocate additional bitmap blocks, reallocate
 120                  * array of bitmap block pointers
 121                  */
 122                 bitmap =
 123                     vzalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
 124                 if (!bitmap) {
 125                         /*
 126                          * Journal bitmaps are still supersized, but the
 127                          * memory isn't leaked, so I guess it's ok
 128                          */
 129                         printk("reiserfs_resize: unable to allocate memory.\n");
 130                         return -ENOMEM;
 131                 }
 132                 for (i = 0; i < bmap_nr; i++)
 133                         bitmap[i] = old_bitmap[i];
 134
 135                 /*
 136                  * This doesn't go through the journal, but it doesn't have to.
 137                  * The changes are still atomic: We're synced up when the
 138                  * journal transaction begins, and the new bitmaps don't
 139                  * matter if the transaction fails.
 140                  */
 141                 for (i = bmap_nr; i < bmap_nr_new; i++) {
 142                         int depth;
 143                         /*
 144                          * don't use read_bitmap_block since it will cache
 145                          * the uninitialized bitmap
 146                          */
 147                         depth = reiserfs_write_unlock_nested(s);
 148                         bh = sb_bread(s, i * s->s_blocksize * 8);
 149                         reiserfs_write_lock_nested(s, depth);
 150                         if (!bh) {
 151                                 vfree(bitmap);
 152                                 return -EIO;
 153                         }
 154                         memset(bh->b_data, 0, sb_blocksize(sb));
 155                         reiserfs_set_le_bit(0, bh->b_data);
 156                         reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
 157
 158                         set_buffer_uptodate(bh);
 159                         mark_buffer_dirty(bh);
 160                         depth = reiserfs_write_unlock_nested(s);
 161                         sync_dirty_buffer(bh);
 162                         reiserfs_write_lock_nested(s, depth);
 163                         /* update bitmap_info stuff */
 164                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 165                         brelse(bh);
 166                 }
 167                 /* free old bitmap blocks array */
 168                 SB_AP_BITMAP(s) = bitmap;
 169                 vfree(old_bitmap);
 170         }
 171
 172         /*
 173          * begin transaction, if there was an error, it's fine. Yes, we have
 174          * incorrect bitmaps now, but none of it is ever going to touch the
 175          * disk anyway.
 176          */
 177         err = journal_begin(&th, s, 10);
 178         if (err)
 179                 return err;
 180
 181         /* Extend old last bitmap block - new blocks have been made available */
 182         info = SB_AP_BITMAP(s) + bmap_nr - 1;
 183         bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
 184         if (!bh) {
 185                 int jerr = journal_end(&th);
 186                 if (jerr)
 187                         return jerr;
 188                 return -EIO;
 189         }
 190
 191         reiserfs_prepare_for_journal(s, bh, 1);
 192         for (i = block_r; i < s->s_blocksize * 8; i++)
 193                 reiserfs_clear_le_bit(i, bh->b_data);
 194         info->free_count += s->s_blocksize * 8 - block_r;
 195
 196         journal_mark_dirty(&th, bh);
 197         brelse(bh);
 198
 199         /* Correct new last bitmap block - It may not be full */
 200         info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
 201         bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
 202         if (!bh) {
 203                 int jerr = journal_end(&th);
 204                 if (jerr)
 205                         return jerr;
 206                 return -EIO;
 207         }
 208
 209         reiserfs_prepare_for_journal(s, bh, 1);
 210         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 211                 reiserfs_set_le_bit(i, bh->b_data);
 212         journal_mark_dirty(&th, bh);
 213         brelse(bh);
 214
 215         info->free_count -= s->s_blocksize * 8 - block_r_new;
 216         /* update super */
 217         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 218         free_blocks = SB_FREE_BLOCKS(s);
 219         PUT_SB_FREE_BLOCKS(s,
 220                            free_blocks + (block_count_new - block_count -
 221                                           (bmap_nr_new - bmap_nr)));
 222         PUT_SB_BLOCK_COUNT(s, block_count_new);
 223         PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
 224
 225         journal_mark_dirty(&th, SB_BUFFER_WITH_SB(s));
 226
 227         SB_JOURNAL(s)->j_must_wait = 1;
 228         return journal_end(&th);
 229 }