linux-hardened/fs/reiserfs/resize.c
Jeff Mahoney cb680c1be6 reiserfs: ignore on disk s_bmap_nr value
Implement support for file systems larger than 8 TiB.

The reiserfs superblock contains a 16 bit value for counting the number of
bitmap blocks.  The rest of the disk format supports file systems up to 2^32
blocks, but the bitmap block limitation artificially limits this to 8 TiB with
a 4KiB block size.

Rather than trust the superblock's 16-bit bitmap block count, we calculate it
dynamically based on the number of blocks in the file system.  When an
incorrect value is observed in the superblock, it is zeroed out, ensuring that
older kernels will not be able to mount the file system.

Userspace support has already been implemented and shipped in reiserfsprogs
3.6.20.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19 11:53:35 -07:00

211 lines
6.2 KiB
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 <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);
}