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 *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
  38         sb = SB_DISK_SUPER_BLOCK(s);
  39
  40         if (SB_BLOCK_COUNT(s) >= block_count_new) {
  41                 printk("can\'t shrink filesystem on-line\n");
  42                 return -EINVAL;
  43         }
  44
  45         /* check the device size */
  46         bh = sb_bread(s, block_count_new - 1);
  47         if (!bh) {
  48                 printk("reiserfs_resize: can\'t read last block\n");
  49                 return -EINVAL;
  50         }
  51         bforget(bh);
  52
  53         /* old disk layout detection; those partitions can be mounted, but
  54          * cannot be resized */
  55         if (SB_BUFFER_WITH_SB(s)->b_blocknr *   SB_BUFFER_WITH_SB(s)->b_size
  56                 != REISERFS_DISK_OFFSET_IN_BYTES ) {
  57                 printk("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
  58                 return -ENOTSUPP;
  59         }
  60
  61         /* count used bits in last bitmap block */
  62         block_r = SB_BLOCK_COUNT(s) -
  63                 (SB_BMAP_NR(s) - 1) * s->s_blocksize * 8;
  64
  65         /* count bitmap blocks in new fs */
  66         bmap_nr_new = block_count_new / ( s->s_blocksize * 8 );
  67         block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  68         if (block_r_new)
  69                 bmap_nr_new++;
  70         else
  71                 block_r_new = s->s_blocksize * 8;
  72
  73         /* save old values */
  74         block_count = SB_BLOCK_COUNT(s);
  75         bmap_nr     = SB_BMAP_NR(s);
  76
  77         /* resizing of reiserfs bitmaps (journal and real), if needed */
  78         if (bmap_nr_new > bmap_nr) {
  79             /* reallocate journal bitmaps */
  80             if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  81                 printk("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  82                 unlock_super(s) ;
  83                 return -ENOMEM ;
  84             }
  85             /* the new journal bitmaps are zero filled, now we copy in the bitmap
  86             ** node pointers from the old journal bitmap structs, and then
  87             ** transfer the new data structures into the journal struct.
  88             **
  89             ** using the copy_size var below allows this code to work for
  90             ** both shrinking and expanding the FS.
  91             */
  92             copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr ;
  93             copy_size = copy_size * sizeof(struct reiserfs_list_bitmap_node *) ;
  94             for (i = 0 ; i < JOURNAL_NUM_BITMAPS ; i++) {
  95                 struct reiserfs_bitmap_node **node_tmp ;
  96                 jb = SB_JOURNAL(s)->j_list_bitmap + i ;
  97                 memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size) ;
  98
  99                 /* just in case vfree schedules on us, copy the new
 100                 ** pointer into the journal struct before freeing the
 101                 ** old one
 102                 */
 103                 node_tmp = jb->bitmaps ;
 104                 jb->bitmaps = jbitmap[i].bitmaps ;
 105                 vfree(node_tmp) ;
 106             }
 107
 108             /* allocate additional bitmap blocks, reallocate array of bitmap
 109              * block pointers */
 110             bitmap = vmalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
 111             if (!bitmap) {
 112                 /* Journal bitmaps are still supersized, but the memory isn't
 113                  * leaked, so I guess it's ok */
 114                 printk("reiserfs_resize: unable to allocate memory.\n");
 115                 return -ENOMEM;
 116             }
 117             memset (bitmap, 0, sizeof (struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
 118             for (i = 0; i < bmap_nr; i++)
 119                 bitmap[i] = old_bitmap[i];
 120
 121             /* This doesn't go through the journal, but it doesn't have to.
 122              * The changes are still atomic: We're synced up when the journal
 123              * transaction begins, and the new bitmaps don't matter if the
 124              * transaction fails. */
 125             for (i = bmap_nr; i < bmap_nr_new; i++) {
 126                 bitmap[i].bh = sb_getblk(s, i * s->s_blocksize * 8);
 127                 memset(bitmap[i].bh->b_data, 0, sb_blocksize(sb));
 128                 reiserfs_test_and_set_le_bit(0, bitmap[i].bh->b_data);
 129
 130                 set_buffer_uptodate(bitmap[i].bh);
 131                 mark_buffer_dirty(bitmap[i].bh) ;
 132                 sync_dirty_buffer(bitmap[i].bh);
 133                 // update bitmap_info stuff
 134                 bitmap[i].first_zero_hint=1;
 135                 bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 136             }
 137             /* free old bitmap blocks array */
 138             SB_AP_BITMAP(s) = bitmap;
 139             vfree (old_bitmap);
 140         }
 141
 142         /* begin transaction, if there was an error, it's fine. Yes, we have
 143          * incorrect bitmaps now, but none of it is ever going to touch the
 144          * disk anyway. */
 145         err = journal_begin(&th, s, 10);
 146         if (err)
 147             return err;
 148
 149         /* correct last bitmap blocks in old and new disk layout */
 150         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr - 1].bh, 1);
 151         for (i = block_r; i < s->s_blocksize * 8; i++)
 152             reiserfs_test_and_clear_le_bit(i,
 153                                            SB_AP_BITMAP(s)[bmap_nr - 1].bh->b_data);
 154         SB_AP_BITMAP(s)[bmap_nr - 1].free_count += s->s_blocksize * 8 - block_r;
 155         if ( !SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint)
 156             SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint = block_r;
 157
 158         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr - 1].bh);
 159
 160         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh, 1);
 161         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 162             reiserfs_test_and_set_le_bit(i,
 163                                          SB_AP_BITMAP(s)[bmap_nr_new - 1].bh->b_data);
 164         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh);
 165
 166         SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count -= s->s_blocksize * 8 - block_r_new;
 167         /* Extreme case where last bitmap is the only valid block in itself. */
 168         if ( !SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count )
 169             SB_AP_BITMAP(s)[bmap_nr_new - 1].first_zero_hint = 0;
 170         /* update super */
 171         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ;
 172         free_blocks = SB_FREE_BLOCKS(s);
 173         PUT_SB_FREE_BLOCKS(s, free_blocks + (block_count_new - block_count - (bmap_nr_new - bmap_nr)));
 174         PUT_SB_BLOCK_COUNT(s, block_count_new);
 175         PUT_SB_BMAP_NR(s, bmap_nr_new);
 176         s->s_dirt = 1;
 177
 178         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 179
 180         SB_JOURNAL(s)->j_must_wait = 1;
 181         return journal_end(&th, s, 10);
 182 }