LXR linux/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
  20int 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) -
  65                        (reiserfs_bmap_count(s) - 1) * s->s_blocksize * 8;
  66
  67        /* count bitmap blocks in new fs */
  68        bmap_nr_new = block_count_new / (s->s_blocksize * 8);
  69        block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
  70        if (block_r_new)
  71                bmap_nr_new++;
  72        else
  73                block_r_new = s->s_blocksize * 8;
  74
  75        /* save old values */
  76        block_count = SB_BLOCK_COUNT(s);
  77        bmap_nr = reiserfs_bmap_count(s);
  78
  79        /* resizing of reiserfs bitmaps (journal and real), if needed */
  80        if (bmap_nr_new > bmap_nr) {
  81                /* reallocate journal bitmaps */
  82                if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
  83                        printk
  84                            ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
  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) * bmap_nr_new);
 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].free_count = sb_blocksize(sb) * 8 - 1;
 147                        brelse(bh);
 148                }
 149                /* free old bitmap blocks array */
 150                SB_AP_BITMAP(s) = bitmap;
 151                vfree(old_bitmap);
 152        }
 153
 154        /* begin transaction, if there was an error, it's fine. Yes, we have
 155         * incorrect bitmaps now, but none of it is ever going to touch the
 156         * disk anyway. */
 157        err = journal_begin(&th, s, 10);
 158        if (err)
 159                return err;
 160
 161        /* Extend old last bitmap block - new blocks have been made available */
 162        info = SB_AP_BITMAP(s) + bmap_nr - 1;
 163        bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
 164        if (!bh) {
 165                int jerr = journal_end(&th, s, 10);
 166                if (jerr)
 167                        return jerr;
 168                return -EIO;
 169        }
 170
 171        reiserfs_prepare_for_journal(s, bh, 1);
 172        for (i = block_r; i < s->s_blocksize * 8; i++)
 173                reiserfs_test_and_clear_le_bit(i, bh->b_data);
 174        info->free_count += s->s_blocksize * 8 - block_r;
 175
 176        journal_mark_dirty(&th, s, bh);
 177        brelse(bh);
 178
 179        /* Correct new last bitmap block - It may not be full */
 180        info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
 181        bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
 182        if (!bh) {
 183                int jerr = journal_end(&th, s, 10);
 184                if (jerr)
 185                        return jerr;
 186                return -EIO;
 187        }
 188
 189        reiserfs_prepare_for_journal(s, bh, 1);
 190        for (i = block_r_new; i < s->s_blocksize * 8; i++)
 191                reiserfs_test_and_set_le_bit(i, bh->b_data);
 192        journal_mark_dirty(&th, s, bh);
 193        brelse(bh);
 194
 195        info->free_count -= s->s_blocksize * 8 - block_r_new;
 196        /* update super */
 197        reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
 198        free_blocks = SB_FREE_BLOCKS(s);
 199        PUT_SB_FREE_BLOCKS(s,
 200                           free_blocks + (block_count_new - block_count -
 201                                          (bmap_nr_new - bmap_nr)));
 202        PUT_SB_BLOCK_COUNT(s, block_count_new);
 203        PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
 204        s->s_dirt = 1;
 205
 206        journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));
 207
 208        SB_JOURNAL(s)->j_must_wait = 1;
 209        return journal_end(&th, s, 10);
 210}
 211