f2fs: do not allow partial truncation on pinned file

If the pinned file has a hole by partial truncation, application that has
the block map will be broken.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Jaegeuk Kim

fs/f2fs/file.c

@@ -1750,7 +1750,11 @@ static long f2fs_fallocate(struct file *file, int mode,
 		(mode & (FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_INSERT_RANGE)))
 		return -EOPNOTSUPP;
 
-	if (f2fs_compressed_file(inode) &&
+	/*
+	 * Pinned file should not support partial trucation since the block
+	 * can be used by applications.
+	 */
+	if ((f2fs_compressed_file(inode) || f2fs_is_pinned_file(inode)) &&
 		(mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE |
 			FALLOC_FL_ZERO_RANGE | FALLOC_FL_INSERT_RANGE)))
 		return -EOPNOTSUPP;