Fix04: Lab4 Errata

Below is a list of incorrect/inaccurate hints and their corrections. This page will be kept updated.

1. [update 11/28] Exercise 1: an incorrect comment in fs5600.h
   fs5600.h has
   uint32_t ctime; // creation time
   The comment is wrong: "ctime" means "change time", meaning: (see also "man 2 stat").
   struct timespec st_ctim; /* Time of last status change */
   
   
2. [update 11/28] Exercise 2: converting "uint32_t" to "struct timespec"
   The hint of treating "struct timespec" as "uint32_t" is a wrong hint (might work on some of machines but not on others). Instead, your code should read the time-related attributes from fs5600 inode and write them to the "struct timespec" attributes of the "struct stat".
   • to see "struct timespec" definition, read "man clock_gettime"
   • to understand what is stored in "ctime/mtime" of fs5600 inode, read the code of "fs_create" (which you will implement in Exercise 4) and "man 2 time" (the return value of "time(NULL)" is what will be put into "ctime/mtime").
   
   
3. [update 11/29] Exercise 3: a confusing rename unit test
   test1.c has the following test cases:
   struct rename_case err1[] = {
...
{"/dir2/file.4k", "/dir3/somefile", EINVAL},
...
};
   You should update "/dir2/file.4k" (a non-existing file) to be "/dir2/file.4k+" (an existing file). This is a typo.
   For the original typoed test case, returning either "EINVAL" or "ENOENT" is fine since the file "/dir2/file.4k" doesn't exist and it violates an fs5600 assumption (rename happens in the same directory).