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 "reiserfs.h"
  17#include <linux/buffer_head.h>
  18
  19int 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}
 230