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ocfs2: validate bg_free_bits_count after update 

This patch adds a safe check to ensure bg_free_bits_count doesn't exceed
bg_bits in a group descriptor. This is to avoid on disk corruption that was
seen recently.

debugfs: group <52803072>
       Group Chain: 179   Parent Inode: 11  Generation: 2959379682
       CRC32: 00000000   ECC: 0000
       ##   Block#            Total    Used     Free     Contig   Size
       0    52803072          32256    4294965350   34202    18207    4032
       ......

Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
This commit is contained in:
Srinivas Eeda 2010-10-05 15:53:06 -07:00 committed by Joel Becker
parent 93f3b86fb1
commit 9b5cd10e4c
1 changed files with 16 additions and 0 deletions
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16
fs/ocfs2/suballoc.c
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@ -1380,6 +1380,14 @@ static inline int ocfs2_block_group_set_bits(handle_t *handle,
}
le16_add_cpu(&bg->bg_free_bits_count, -num_bits);
if (le16_to_cpu(bg->bg_free_bits_count) > le16_to_cpu(bg->bg_bits)) {
ocfs2_error(alloc_inode->i_sb, "Group descriptor # %llu has bit"
" count %u but claims %u are freed. num_bits %d",
(unsigned long long)le64_to_cpu(bg->bg_blkno),
le16_to_cpu(bg->bg_bits),
le16_to_cpu(bg->bg_free_bits_count), num_bits);
return -EROFS;
}
while(num_bits--)
ocfs2_set_bit(bit_off++, bitmap);
@ -2419,6 +2427,14 @@ static int ocfs2_block_group_clear_bits(handle_t *handle,
(unsigned long *) undo_bg->bg_bitmap);
}
le16_add_cpu(&bg->bg_free_bits_count, num_bits);
if (le16_to_cpu(bg->bg_free_bits_count) > le16_to_cpu(bg->bg_bits)) {
ocfs2_error(alloc_inode->i_sb, "Group descriptor # %llu has bit"
" count %u but claims %u are freed. num_bits %d",
(unsigned long long)le64_to_cpu(bg->bg_blkno),
le16_to_cpu(bg->bg_bits),
le16_to_cpu(bg->bg_free_bits_count), num_bits);
return -EROFS;
}
if (undo_fn)
jbd_unlock_bh_state(group_bh);