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root/fs/reiserfs/resize.c

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DEFINITIONS

This source file includes following definitions.
  1. reiserfs_resize

/* 
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

/* 
 * Written by Alexander Zarochentcev.
 *
 * The kernel part of the (on-line) reiserfs resizer.
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/reiserfs_fs.h>
#include <linux/reiserfs_fs_sb.h>
#include <linux/buffer_head.h>

int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
{
        int err = 0;
        struct reiserfs_super_block *sb;
        struct reiserfs_bitmap_info *bitmap;
        struct reiserfs_bitmap_info *info;
        struct reiserfs_bitmap_info *old_bitmap = SB_AP_BITMAP(s);
        struct buffer_head *bh;
        struct reiserfs_transaction_handle th;
        unsigned int bmap_nr_new, bmap_nr;
        unsigned int block_r_new, block_r;

        struct reiserfs_list_bitmap *jb;
        struct reiserfs_list_bitmap jbitmap[JOURNAL_NUM_BITMAPS];

        unsigned long int block_count, free_blocks;
        int i;
        int copy_size;

        sb = SB_DISK_SUPER_BLOCK(s);

        if (SB_BLOCK_COUNT(s) >= block_count_new) {
                printk("can\'t shrink filesystem on-line\n");
                return -EINVAL;
        }

        /* check the device size */
        bh = sb_bread(s, block_count_new - 1);
        if (!bh) {
                printk("reiserfs_resize: can\'t read last block\n");
                return -EINVAL;
        }
        bforget(bh);

        /* old disk layout detection; those partitions can be mounted, but
         * cannot be resized */
        if (SB_BUFFER_WITH_SB(s)->b_blocknr * SB_BUFFER_WITH_SB(s)->b_size
            != REISERFS_DISK_OFFSET_IN_BYTES) {
                printk
                    ("reiserfs_resize: unable to resize a reiserfs without distributed bitmap (fs version < 3.5.12)\n");
                return -ENOTSUPP;
        }

        /* count used bits in last bitmap block */
        block_r = SB_BLOCK_COUNT(s) -
                        (reiserfs_bmap_count(s) - 1) * s->s_blocksize * 8;

        /* count bitmap blocks in new fs */
        bmap_nr_new = block_count_new / (s->s_blocksize * 8);
        block_r_new = block_count_new - bmap_nr_new * s->s_blocksize * 8;
        if (block_r_new)
                bmap_nr_new++;
        else
                block_r_new = s->s_blocksize * 8;

        /* save old values */
        block_count = SB_BLOCK_COUNT(s);
        bmap_nr = reiserfs_bmap_count(s);

        /* resizing of reiserfs bitmaps (journal and real), if needed */
        if (bmap_nr_new > bmap_nr) {
                /* reallocate journal bitmaps */
                if (reiserfs_allocate_list_bitmaps(s, jbitmap, bmap_nr_new) < 0) {
                        printk
                            ("reiserfs_resize: unable to allocate memory for journal bitmaps\n");
                        unlock_super(s);
                        return -ENOMEM;
                }
                /* the new journal bitmaps are zero filled, now we copy in the bitmap
                 ** node pointers from the old journal bitmap structs, and then
                 ** transfer the new data structures into the journal struct.
                 **
                 ** using the copy_size var below allows this code to work for
                 ** both shrinking and expanding the FS.
                 */
                copy_size = bmap_nr_new < bmap_nr ? bmap_nr_new : bmap_nr;
                copy_size =
                    copy_size * sizeof(struct reiserfs_list_bitmap_node *);
                for (i = 0; i < JOURNAL_NUM_BITMAPS; i++) {
                        struct reiserfs_bitmap_node **node_tmp;
                        jb = SB_JOURNAL(s)->j_list_bitmap + i;
                        memcpy(jbitmap[i].bitmaps, jb->bitmaps, copy_size);

                        /* just in case vfree schedules on us, copy the new
                         ** pointer into the journal struct before freeing the 
                         ** old one
                         */
                        node_tmp = jb->bitmaps;
                        jb->bitmaps = jbitmap[i].bitmaps;
                        vfree(node_tmp);
                }

                /* allocate additional bitmap blocks, reallocate array of bitmap
                 * block pointers */
                bitmap =
                    vmalloc(sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
                if (!bitmap) {
                        /* Journal bitmaps are still supersized, but the memory isn't
                         * leaked, so I guess it's ok */
                        printk("reiserfs_resize: unable to allocate memory.\n");
                        return -ENOMEM;
                }
                memset(bitmap, 0,
                       sizeof(struct reiserfs_bitmap_info) * bmap_nr_new);
                for (i = 0; i < bmap_nr; i++)
                        bitmap[i] = old_bitmap[i];

                /* This doesn't go through the journal, but it doesn't have to.
                 * The changes are still atomic: We're synced up when the journal
                 * transaction begins, and the new bitmaps don't matter if the
                 * transaction fails. */
                for (i = bmap_nr; i < bmap_nr_new; i++) {
                        /* don't use read_bitmap_block since it will cache
                         * the uninitialized bitmap */
                        bh = sb_bread(s, i * s->s_blocksize * 8);
                        if (!bh) {
                                vfree(bitmap);
                                return -EIO;
                        }
                        memset(bh->b_data, 0, sb_blocksize(sb));
                        reiserfs_test_and_set_le_bit(0, bh->b_data);
                        reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);

                        set_buffer_uptodate(bh);
                        mark_buffer_dirty(bh);
                        sync_dirty_buffer(bh);
                        // update bitmap_info stuff
                        bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
                        brelse(bh);
                }
                /* free old bitmap blocks array */
                SB_AP_BITMAP(s) = bitmap;
                vfree(old_bitmap);
        }

        /* begin transaction, if there was an error, it's fine. Yes, we have
         * incorrect bitmaps now, but none of it is ever going to touch the
         * disk anyway. */
        err = journal_begin(&th, s, 10);
        if (err)
                return err;

        /* Extend old last bitmap block - new blocks have been made available */
        info = SB_AP_BITMAP(s) + bmap_nr - 1;
        bh = reiserfs_read_bitmap_block(s, bmap_nr - 1);
        if (!bh) {
                int jerr = journal_end(&th, s, 10);
                if (jerr)
                        return jerr;
                return -EIO;
        }

        reiserfs_prepare_for_journal(s, bh, 1);
        for (i = block_r; i < s->s_blocksize * 8; i++)
                reiserfs_test_and_clear_le_bit(i, bh->b_data);
        info->free_count += s->s_blocksize * 8 - block_r;

        journal_mark_dirty(&th, s, bh);
        brelse(bh);

        /* Correct new last bitmap block - It may not be full */
        info = SB_AP_BITMAP(s) + bmap_nr_new - 1;
        bh = reiserfs_read_bitmap_block(s, bmap_nr_new - 1);
        if (!bh) {
                int jerr = journal_end(&th, s, 10);
                if (jerr)
                        return jerr;
                return -EIO;
        }

        reiserfs_prepare_for_journal(s, bh, 1);
        for (i = block_r_new; i < s->s_blocksize * 8; i++)
                reiserfs_test_and_set_le_bit(i, bh->b_data);
        journal_mark_dirty(&th, s, bh);
        brelse(bh);

        info->free_count -= s->s_blocksize * 8 - block_r_new;
        /* update super */
        reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
        free_blocks = SB_FREE_BLOCKS(s);
        PUT_SB_FREE_BLOCKS(s,
                           free_blocks + (block_count_new - block_count -
                                          (bmap_nr_new - bmap_nr)));
        PUT_SB_BLOCK_COUNT(s, block_count_new);
        PUT_SB_BMAP_NR(s, bmap_would_wrap(bmap_nr_new) ? : bmap_nr_new);
        s->s_dirt = 1;

        journal_mark_dirty(&th, s, SB_BUFFER_WITH_SB(s));

        SB_JOURNAL(s)->j_must_wait = 1;
        return journal_end(&th, s, 10);
}

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