From 9b5cd10e4c14a1a642076ace6a73be3d33c91fb6 Mon Sep 17 00:00:00 2001 From: Srinivas Eeda Date: Tue, 5 Oct 2010 15:53:06 -0700 Subject: [PATCH] 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 Signed-off-by: Joel Becker --- fs/ocfs2/suballoc.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c index 8a286f54dca..64f2c50a1c3 100644 --- a/fs/ocfs2/suballoc.c +++ b/fs/ocfs2/suballoc.c @@ -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); -- 2.43.2