- 根目录:
- fs
- reiserfs
- resize.c
/*
* 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 "reiserfs.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;
int depth;
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 */
depth = reiserfs_write_unlock_nested(s);
bh = sb_bread(s, block_count_new - 1);
reiserfs_write_lock_nested(s, depth);
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");
return -ENOMEM;
}
/*
* the new journal bitmaps are zero filled, now we copy i
* 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 =
vzalloc(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;
}
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++) {
int depth;
/*
* don't use read_bitmap_block since it will cache
* the uninitialized bitmap
*/
depth = reiserfs_write_unlock_nested(s);
bh = sb_bread(s, i * s->s_blocksize * 8);
reiserfs_write_lock_nested(s, depth);
if (!bh) {
vfree(bitmap);
return -EIO;
}
memset(bh->b_data, 0, sb_blocksize(sb));
reiserfs_set_le_bit(0, bh->b_data);
reiserfs_cache_bitmap_metadata(s, bh, bitmap + i);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
depth = reiserfs_write_unlock_nested(s);
sync_dirty_buffer(bh);
reiserfs_write_lock_nested(s, depth);
/* 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);
if (jerr)
return jerr;
return -EIO;
}
reiserfs_prepare_for_journal(s, bh, 1);
for (i = block_r; i < s->s_blocksize * 8; i++)
reiserfs_clear_le_bit(i, bh->b_data);
info->free_count += s->s_blocksize * 8 - block_r;
journal_mark_dirty(&th, 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);
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_set_le_bit(i, bh->b_data);
journal_mark_dirty(&th, 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);
journal_mark_dirty(&th, SB_BUFFER_WITH_SB(s));
SB_JOURNAL(s)->j_must_wait = 1;
return journal_end(&th);
}