The reiserfs disk format is designed to handle file systems up to
2^32-1 blocks, which at 4KiB blocks means ~ 16 TiB - 4KiB.
Unfortunately, the superblock's s_bmap_nr value, which contains a
count of the number of bitmap blocks in the file system is a 16 bit
value. This limits the usable size of the file system to
8 TiB (4096^2 * 8 * 65536).
This patch implements the changes introduced with reiserfsprogs 3.6.20,
where s_bmap_nr is zeroed out if the value would overflow.
Older implementations will see the zero value of s_bmap_nr and abort
the mount due to a vmalloc(0) before reading the bitmaps. This is safer
than the current behavior which can result in corruption or BUG's.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/reiserfs/bitmap.c | 39 ++++++++++++++++++++++-----------------
fs/reiserfs/journal.c | 6 +++---
fs/reiserfs/resize.c | 6 +++---
fs/reiserfs/super.c | 15 +++++++++++++++
include/linux/reiserfs_fs.h | 5 +++++
include/linux/reiserfs_fs_sb.h | 1 +
6 files changed, 49 insertions(+), 23 deletions(-)
--- a/fs/reiserfs/bitmap.c 2007-08-08 15:59:01.000000000 -0400
+++ b/fs/reiserfs/bitmap.c 2007-08-08 16:09:59.000000000 -0400
@@ -62,6 +62,7 @@ static inline void get_bit_address(struc
int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value)
{
unsigned int bmap, offset;
+ unsigned int bmap_count = reiserfs_bmap_count(s);
if (block == 0 || block >= SB_BLOCK_COUNT(s)) {
reiserfs_warning(s,
@@ -77,25 +78,26 @@ int is_reusable(struct super_block *s, b
if (unlikely(test_bit(REISERFS_OLD_FORMAT,
&(REISERFS_SB(s)->s_properties)))) {
b_blocknr_t bmap1 = REISERFS_SB(s)->s_sbh->b_blocknr + 1;
- if (block >= bmap1 && block <= bmap1 + SB_BMAP_NR(s)) {
+ if (block >= bmap1 &&
+ block <= bmap1 + bmap_count) {
reiserfs_warning(s, "vs: 4019: is_reusable: "
"bitmap block %lu(%u) can't be freed or reused",
- block, SB_BMAP_NR(s));
+ block, bmap_count);
return 0;
}
} else {
if (offset == 0) {
reiserfs_warning(s, "vs: 4020: is_reusable: "
"bitmap block %lu(%u) can't be freed or reused",
- block, SB_BMAP_NR(s));
+ block, bmap_count);
return 0;
}
}
- if (bmap >= SB_BMAP_NR(s)) {
+ if (bmap >= bmap_count) {
reiserfs_warning(s,
"vs-4030: is_reusable: there is no so many bitmap blocks: "
- "block=%lu, bitmap_nr=%d", block, bmap);
+ "block=%lu, bitmap_nr=%u", block, bmap);
return 0;
}
@@ -145,8 +147,8 @@ static int scan_bitmap_block(struct reis
BUG_ON(!th->t_trans_id);
- RFALSE(bmap_n >= SB_BMAP_NR(s), "Bitmap %d is out of range (0..%d)",
- bmap_n, SB_BMAP_NR(s) - 1);
+ RFALSE(bmap_n >= reiserfs_bmap_count(s), "Bitmap %u is out of "
+ "range (0..%u)", bmap_n, reiserfs_bmap_count(s) - 1);
PROC_INFO_INC(s, scan_bitmap.bmap);
/* this is unclear and lacks comments, explain how journal bitmaps
work here for the reader. Convey a sense of the design here. What
@@ -251,12 +253,12 @@ static int bmap_hash_id(struct super_blo
} else {
hash_in = (char *)(&id);
hash = keyed_hash(hash_in, 4);
- bm = hash % SB_BMAP_NR(s);
+ bm = hash % reiserfs_bmap_count(s);
if (!bm)
bm = 1;
}
/* this can only be true when SB_BMAP_NR = 1 */
- if (bm >= SB_BMAP_NR(s))
+ if (bm >= reiserfs_bmap_count(s))
bm = 0;
return bm;
}
@@ -330,10 +332,10 @@ static int scan_bitmap(struct reiserfs_t
get_bit_address(s, *start, &bm, &off);
get_bit_address(s, finish, &end_bm, &end_off);
- if (bm > SB_BMAP_NR(s))
+ if (bm > reiserfs_bmap_count(s))
return 0;
- if (end_bm > SB_BMAP_NR(s))
- end_bm = SB_BMAP_NR(s);
+ if (end_bm > reiserfs_bmap_count(s))
+ end_bm = reiserfs_bmap_count(s);
/* When the bitmap is more than 10% free, anyone can allocate.
* When it's less than 10% free, only files that already use the
@@ -399,10 +401,12 @@ static void _reiserfs_free_block(struct
get_bit_address(s, block, &nr, &offset);
- if (nr >= sb_bmap_nr(rs)) {
+ if (nr >= reiserfs_bmap_count(s)) {
reiserfs_warning(s, "vs-4075: reiserfs_free_block: "
- "block %lu is out of range on %s",
- block, reiserfs_bdevname(s));
+ "block %lu is out of range on %s "
+ "(nr=%u,max=%u)", block,
+ reiserfs_bdevname(s), nr,
+ reiserfs_bmap_count(s));
return;
}
@@ -1326,12 +1330,13 @@ struct buffer_head *reiserfs_read_bitmap
int reiserfs_init_bitmap_cache(struct super_block *sb)
{
struct reiserfs_bitmap_info *bitmap;
+ unsigned int bmap_nr = reiserfs_bmap_count(sb);
- bitmap = vmalloc(sizeof (*bitmap) * SB_BMAP_NR(sb));
+ bitmap = vmalloc(sizeof (*bitmap) * bmap_nr);
if (bitmap == NULL)
return -ENOMEM;
- memset(bitmap, 0, sizeof (*bitmap) * SB_BMAP_NR(sb));
+ memset(bitmap, 0, sizeof (*bitmap) * bmap_nr);
SB_AP_BITMAP(sb) = bitmap;
--- a/fs/reiserfs/journal.c 2007-08-08 15:59:01.000000000 -0400
+++ b/fs/reiserfs/journal.c 2007-08-08 16:03:29.000000000 -0400
@@ -240,7 +240,7 @@ static void cleanup_bitmap_list(struct s
if (jb->bitmaps == NULL)
return;
- for (i = 0; i < SB_BMAP_NR(p_s_sb); i++) {
+ for (i = 0; i < reiserfs_bmap_count(p_s_sb); i++) {
if (jb->bitmaps[i]) {
free_bitmap_node(p_s_sb, jb->bitmaps[i]);
jb->bitmaps[i] = NULL;
@@ -2651,7 +2651,7 @@ int journal_init(struct super_block *p_s
journal->j_persistent_trans = 0;
if (reiserfs_allocate_list_bitmaps(p_s_sb,
journal->j_list_bitmap,
- SB_BMAP_NR(p_s_sb)))
+ reiserfs_bmap_count(p_s_sb)))
goto free_and_return;
allocate_bitmap_nodes(p_s_sb);
@@ -2659,7 +2659,7 @@ int journal_init(struct super_block *p_s
SB_JOURNAL_1st_RESERVED_BLOCK(p_s_sb) = (old_format ?
REISERFS_OLD_DISK_OFFSET_IN_BYTES
/ p_s_sb->s_blocksize +
- SB_BMAP_NR(p_s_sb) +
+ reiserfs_bmap_count(p_s_sb) +
1 :
REISERFS_DISK_OFFSET_IN_BYTES /
p_s_sb->s_blocksize + 2);
--- a/fs/reiserfs/resize.c 2007-08-08 15:59:01.000000000 -0400
+++ b/fs/reiserfs/resize.c 2007-08-08 16:04:14.000000000 -0400
@@ -61,7 +61,7 @@ int reiserfs_resize(struct super_block *
}
/* count used bits in last bitmap block */
- block_r = SB_BLOCK_COUNT(s) - (SB_BMAP_NR(s) - 1) * s->s_blocksize * 8;
+ 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);
@@ -73,7 +73,7 @@ int reiserfs_resize(struct super_block *
/* save old values */
block_count = SB_BLOCK_COUNT(s);
- bmap_nr = SB_BMAP_NR(s);
+ bmap_nr = reiserfs_bmap_count(s);
/* resizing of reiserfs bitmaps (journal and real), if needed */
if (bmap_nr_new > bmap_nr) {
@@ -206,7 +206,7 @@ int reiserfs_resize(struct super_block *
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_nr_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));
--- a/fs/reiserfs/super.c 2007-08-08 15:59:01.000000000 -0400
+++ b/fs/reiserfs/super.c 2007-08-08 16:04:51.000000000 -0400
@@ -1713,6 +1713,21 @@ static int reiserfs_fill_super(struct su
set_sb_umount_state(rs, REISERFS_ERROR_FS);
set_sb_fs_state(rs, 0);
+ /* Clear out s_bmap_nr if it would wrap. We can handle this
+ * case, but older revisions can't. This will cause the
+ * file system to fail mount on those older implementations,
+ * avoiding corruption. -jeffm */
+ if (bmap_would_wrap(reiserfs_bmap_count(s)) &&
+ sb_bmap_nr(rs) != 0) {
+ reiserfs_warning(s, "super-2030: This file system "
+ "claims to use %u bitmap blocks in "
+ "its super block, but requires %u. "
+ "Clearing to zero.", sb_bmap_nr(rs),
+ reiserfs_bmap_count(s));
+
+ set_sb_bmap_nr(rs, 0);
+ }
+
if (old_format_only(s)) {
/* filesystem of format 3.5 either with standard or non-standard
journal */
--- a/include/linux/reiserfs_fs.h 2007-08-08 15:59:01.000000000 -0400
+++ b/include/linux/reiserfs_fs.h 2007-08-08 16:10:59.000000000 -0400
@@ -229,6 +229,11 @@ struct reiserfs_super_block {
((!is_reiserfs_jr(SB_DISK_SUPER_BLOCK(s)) ? \
SB_ONDISK_JOURNAL_SIZE(s) + 1 : SB_ONDISK_RESERVED_FOR_JOURNAL(s)))
+/* s_bmap_nr is a u16 */
+#define reiserfs_bmap_count(sb) reiserfs_bmap_nr(SB_BLOCK_COUNT(sb), sb->s_blocksize)
+#define reiserfs_bmap_nr(count, blk_size) ((count - 1) / (blk_size * 8) + 1)
+#define bmap_would_wrap(n) (n > ((1LL << 16) - 1))
+
int is_reiserfs_3_5(struct reiserfs_super_block *rs);
int is_reiserfs_3_6(struct reiserfs_super_block *rs);
int is_reiserfs_jr(struct reiserfs_super_block *rs);
--- a/include/linux/reiserfs_fs_sb.h 2007-08-08 15:59:01.000000000 -0400
+++ b/include/linux/reiserfs_fs_sb.h 2007-08-08 15:59:03.000000000 -0400
@@ -410,6 +410,7 @@ struct reiserfs_sb_info {
char *s_qf_names[MAXQUOTAS];
int s_jquota_fmt;
#endif
+ unsigned int s_bmap_nr;
};
/* Definitions of reiserfs on-disk properties: */
--
Jeff Mahoney
SUSE Labs
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