bfs: fix bitmap size argument to find_first_zero_bit()

The usage of find_first_zero_bit() in bfs_create() is wrong for two reasons.

The bitmap size argument to find_first_zero_bit() is info->si_lasti but the correct bitmap size is info->si_lasti + 1 as info->si_lasti is the last valid index in info->si_imap bitmap.

Another problem is that it is impossible to detect that info->si_imap bitmap is full because there is an off-by-one bug in the return value check for find_first_zero_bit(). If no zero bits exist in info->si_imap, find_first_zero_bit() returns info->si_lasti. But the check can't catch it due to the off-by-one.

---
 fs/bfs/dir.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 685ecff..b14cebf 100644
@@ -97,7 +97,7 @@ static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
 	if (!inode)
 		return -ENOSPC;
 	mutex_lock(&info->bfs_lock);
-	ino = find_first_zero_bit(info->si_imap, info->si_lasti);
+	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
 	if (ino > info->si_lasti) {
 		mutex_unlock(&info->bfs_lock);
 		iput(inode);

1.7.4