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btrfs-progs: fix unaligned access calculating raid56 data 

The extent_buffer::data might be unaligned wrt unsigned long, depends on
acutal layout of the structure and width of the int types. Use explicit
unaligned access helpers.

Reported-by: Anatoly Pugachev <matorola@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
master
David Sterba 2016-07-27 22:30:52 +02:00
parent 1c47e5b039
commit 24f1713777
1 changed files with 8 additions and 3 deletions
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11
volumes.c
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@ -2154,9 +2154,14 @@ int write_raid56_with_parity(struct btrfs_fs_info *info,
ebs[multi->num_stripes - 1] = p_eb;
memcpy(p_eb->data, ebs[0]->data, stripe_len);
for (j = 1; j < multi->num_stripes - 1; j++) {
for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
*(unsigned long *)(p_eb->data + i) ^=
*(unsigned long *)(ebs[j]->data + i);
for (i = 0; i < stripe_len; i += sizeof(u64)) {
u64 p_eb_data;
u64 ebs_data;
p_eb_data = get_unaligned_64(p_eb->data + i);
ebs_data = get_unaligned_64(ebs[j]->data + i);
p_eb_data ^= ebs_data;
put_unaligned_64(p_eb_data, p_eb->data + i);
}
}
}