fs/ntfs3: check for shutdown in fsync

Ensure fsync() returns -EIO when the ntfs3 filesystem is in forced
shutdown, instead of silently succeeding via generic_file_fsync().

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: aalexandrovich

fs/ntfs3/file.c

@@ -1440,6 +1440,18 @@ static ssize_t ntfs_file_splice_write(struct pipe_inode_info *pipe,
 	return iter_file_splice_write(pipe, file, ppos, len, flags);
 }
 
+/*
+ * ntfs_file_fsync - file_operations::fsync
+ */
+static int ntfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	struct inode *inode = file_inode(file);
+	if (unlikely(ntfs3_forced_shutdown(inode->i_sb)))
+		return -EIO;
+
+	return generic_file_fsync(file, start, end, datasync);
+}
+
 // clang-format off
 const struct inode_operations ntfs_file_inode_operations = {
 	.getattr	= ntfs_getattr,
@@ -1462,7 +1474,7 @@ const struct file_operations ntfs_file_operations = {
 	.splice_write	= ntfs_file_splice_write,
 	.mmap_prepare	= ntfs_file_mmap_prepare,
 	.open		= ntfs_file_open,
-	.fsync		= generic_file_fsync,
+	.fsync		= ntfs_file_fsync,
 	.fallocate	= ntfs_fallocate,
 	.release	= ntfs_file_release,
 };