ext4: in ext4_seek_{hole,data}, return -ENXIO for negative offsets

commit 1bd8d6cd3e413d64e543ec3e69ff43e75a1cf1ea upstream.

In the ext4 implementations of SEEK_HOLE and SEEK_DATA, make sure we
return -ENXIO for negative offsets instead of banging around inside
the extent code and returning -EFSCORRUPTED.

Reported-by: Mateusz S <muttdini@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: djwong

fs/ext4/file.c

@@ -559,7 +559,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
 	mutex_lock(&inode->i_mutex);
 
 	isize = i_size_read(inode);
-	if (offset >= isize) {
+	if (offset < 0 || offset >= isize) {
 		mutex_unlock(&inode->i_mutex);
 		return -ENXIO;
 	}
@@ -632,7 +632,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
 	mutex_lock(&inode->i_mutex);
 
 	isize = i_size_read(inode);
-	if (offset >= isize) {
+	if (offset < 0 || offset >= isize) {
 		mutex_unlock(&inode->i_mutex);
 		return -ENXIO;
 	}