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 *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
  58                     ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
  59                 return -ENOTSUPP;
  60         }
  61
  62         /* count used bits in last bitmap block */
  63         block_r = SB_BLOCK_COUNT(s) - (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
  82                             ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  83                         unlock_super(s);
  84                         return -ENOMEM;
  85                 }
  86                 /* the new journal bitmaps are zero filled, now we copy in the bitmap
  87                  ** node pointers from the old journal bitmap structs, and then
  88                  ** transfer the new data structures into the journal struct.
  89                  **
  90                  ** using the copy_size var below allows this code to work for
  91                  ** both shrinking and expanding the FS.
  92                  */
  93                 copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
  94                 copy_size =
  95                     copy_size * sizeof(struct reiserfs_list_bitmap_node *);
  96                 for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
  97                         struct reiserfs_bitmap_node **node_tmp;
  98                         jb = SB_JOURNAL(s)->j_list_bitmap + i;
  99                         memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);
 100
 101                         /* just in case vfree schedules on us, copy the new
 102                          ** pointer into the journal struct before freeing the
 103                          ** old one
 104                          */
 105                         node_tmp = jb->bitmaps;
 106                         jb->bitmaps = jbitmap[i].bitmaps;
 107                         vfree(node_tmp);
 108                 }
 109
 110                 /* allocate additional bitmap blocks, reallocate array of bitmap
 111                  * block pointers */
 112                 bitmap =
 113                     vmalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
 114                 if (!bitmap) {
 115                         /* Journal bitmaps are still supersized, but the memory isn't
 116                          * leaked, so I guess it's ok */
 117                         printk("reiserfs_resize: unable to allocate memory.\n");
 118                         return -ENOMEM;
 119                 }
 120                 memset(bitmap, 0,
 121                        sizeof(struct reiserfs_bitmap_info) * SB_BMAP_NR(s));
 122                 for (i = 0; i < bmap_nr; i++)
 123                         bitmap[i] = old_bitmap[i];
 124
 125                 /* This doesn't go through the journal, but it doesn't have to.
 126                  * The changes are still atomic: We're synced up when the journal
 127                  * transaction begins, and the new bitmaps don't matter if the
 128                  * transaction fails. */
 129                 for (i = bmap_nr; i < bmap_nr_new; i++) {
 130                         bitmap[i].bh = sb_getblk(s, i * s->s_blocksize * 8);
 131                         memset(bitmap[i].bh->b_data, 0, sb_blocksize(sb));
 132                         reiserfs_test_and_set_le_bit(0, bitmap[i].bh->b_data);
 133
 134                         set_buffer_uptodate(bitmap[i].bh);
 135                         mark_buffer_dirty(bitmap[i].bh);
 136                         sync_dirty_buffer(bitmap[i].bh);
 137                         // update bitmap_info stuff
 138                         bitmap[i].first_zero_hint = 1;
 139                         bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
 140                 }
 141                 /* free old bitmap blocks array */
 142                 SB_AP_BITMAP(s) = bitmap;
 143                 vfree(old_bitmap);
 144         }
 145
 146         /* begin transaction, if there was an error, it's fine. Yes, we have
 147          * incorrect bitmaps now, but none of it is ever going to touch the
 148          * disk anyway. */
 149         err = journal_begin(&th, s, 10);
 150         if (err)
 151                 return err;
 152
 153         /* correct last bitmap blocks in old and new disk layout */
 154         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr - 1].bh, 1);
 155         for (i = block_r; i < s->s_blocksize * 8; i++)
 156                 reiserfs_test_and_clear_le_bit(i,
 157                                                SB_AP_BITMAP(s)[bmap_nr -
 158                                                                1].bh->b_data);
 159         SB_AP_BITMAP(s)[bmap_nr - 1].free_count += s->s_blocksize * 8 - block_r;
 160         if (!SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint)
 161                 SB_AP_BITMAP(s)[bmap_nr - 1].first_zero_hint = block_r;
 162
 163         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr - 1].bh);
 164
 165         reiserfs_prepare_for_journal(s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh, 1);
 166         for (i = block_r_new; i < s->s_blocksize * 8; i++)
 167                 reiserfs_test_and_set_le_bit(i,
 168                                              SB_AP_BITMAP(s)[bmap_nr_new -
 169                                                              1].bh->b_data);
 170         journal_mark_dirty(&th, s, SB_AP_BITMAP(s)[bmap_nr_new - 1].bh);
 171
 172         SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count -=
 173             s->s_blocksize * 8 - block_r_new;
 174         /* Extreme case where last bitmap is the only valid block in itself. */
 175         if (!SB_AP_BITMAP(s)[bmap_nr_new - 1].free_count)
 176                 SB_AP_BITMAP(s)[bmap_nr_new - 1].first_zero_hint = 0;
 177         /* update super */
 178         reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 179         free_blocks = SB_FREE_BLOCKS(s);
 180         PUT_SB_FREE_BLOCKS(s,
 181                            free_blocks + (block_count_new - block_count -
 182                                           (bmap_nr_new - bmap_nr)));
 183         PUT_SB_BLOCK_COUNT(s, block_count_new);
 184         PUT_SB_BMAP_NR(s, bmap_nr_new);
 185         s->s_dirt = 1;
 186
 187         journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 188
 189         SB_JOURNAL(s)->j_must_wait = 1;
 190         return journal_end(&th, s, 10);
 191 }