ext4: align max orphan file size with e2fsprogs limit

Kernel commit 0a6ce20c1564 ("ext4: verify orphan file size is not too big")
limits the maximum supported orphan file size to 8 << 20.

However, in e2fsprogs, the orphan file size is set to 32–512 filesystem
blocks when creating a filesystem.

With 64k block size, formatting an ext4 fs >32G gives an orphan file bigger
than the kernel allows, so mount prints an error and fails:

EXT4-fs (vdb): orphan file too big: 8650752
EXT4-fs (vdb): mount failed

To prevent this issue and allow previously created 64KB filesystems to
mount, we updates the maximum allowed orphan file size in the kernel to
512 filesystem blocks.

Fixes: 0a6ce20c1564 ("ext4: verify orphan file size is not too big")
Signed-off-by: Baokun Li <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Message-ID: <[e-mail]>
Signed-off-by: Theodore Ts'o <[e-mail]>
Cc: [e-mail]

fs/ext4/orphan.c

···
 #include "ext4.h"
 #include "ext4_jbd2.h"
 
+#define EXT4_MAX_ORPHAN_FILE_BLOCKS 512
+
 static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
 {
 	int i, j, start;
···
 	 * consuming absurd amounts of memory when pinning blocks of orphan
 	 * file in memory.
 	 */
-	if (inode->i_size > 8 << 20) {
+	if (inode->i_size > (EXT4_MAX_ORPHAN_FILE_BLOCKS << inode->i_blkbits)) {
 		ext4_msg(sb, KERN_ERR, "orphan file too big: %llu",
 			 (unsigned long long)inode->i_size);
 		ret = -EFSCORRUPTED;