btrfs: define BTRFS_MAGIC as a u64 value
super.magic is an le64 but it's treated as an unterminated string when
compared against BTRFS_MAGIC which is defined as a string. Instead
define BTRFS_MAGIC as a normal hex value and use endian helpers to
compare it to the super's magic.
I tested this by mounting an fs made before the change and made sure
that it didn't introduce sparse errors. This matches a similar cleanup
that is pending in btrfs-progs. David Sterba pointed out that we should
fix the kernel side as well :).
Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e511d9f..39ff34a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2407,8 +2407,7 @@
sb->s_blocksize = sectorsize;
sb->s_blocksize_bits = blksize_bits(sectorsize);
- if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
- sizeof(disk_super->magic))) {
+ if (disk_super->magic != cpu_to_le64(BTRFS_MAGIC)) {
printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
goto fail_sb_buffer;
}
@@ -2815,8 +2814,7 @@
super = (struct btrfs_super_block *)bh->b_data;
if (btrfs_super_bytenr(super) != bytenr ||
- strncmp((char *)(&super->magic), BTRFS_MAGIC,
- sizeof(super->magic))) {
+ super->magic != cpu_to_le64(BTRFS_MAGIC)) {
brelse(bh);
continue;
}
