staging: exfat: Update the TODO file

Updating with the current laundry list of things that need attention.
Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112223609.163501-1-Valdis.Kletnieks@vt.eduSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/exfat/TODO

+A laundry list of things that need looking at, most of which will
+require more work than the average checkpatch cleanup...
+
+Note that some of these entries may not be bugs - they're things
+that need to be looked at, and *possibly* fixed.
+
+Clean up the ffsCamelCase function names.
+
+Fix (thing)->flags to not use magic numbers - multiple offenders
+
+Sort out all the s32/u32/u8 nonsense - most of these should be plain int.
+
 exfat_core.c - ffsReadFile - the goto err_out seem to leak a brelse().
 same for ffsWriteFile.
 
-exfat_core.c - fs_sync(sb,0) all over the place looks fishy as hell.
-There's only one place that calls it with a non-zero argument.
-Randomly removing fs_sync() calls is *not* the right answer, especially
-if the removal then leaves a call to fs_set_vol_flags(VOL_CLEAN), as that
-says the file system is clean and synced when we *know* it isn't.
-The proper fix here is to go through and actually analyze how DELAYED_SYNC
-should work, and any time we're setting VOL_CLEAN, ensure the file system
-has in fact been synced to disk.  In other words, changing the 'false' to
-'true' is probably more correct. Also, it's likely that the one current
-place where it actually does an bdev_sync isn't sufficient in the DELAYED_SYNC
-case.
+All the calls to fs_sync() need to be looked at, particularly in the
+context of EXFAT_DELAYED_SYNC. Currently, if that's defined, we only
+flush to disk when sync() gets called.  We should be doing at least
+metadata flushes at appropriate times.
 
 ffsTruncateFile -  if (old_size <= new_size) {
 That doesn't look right. How did it ever work? Are they relying on lazy
@@ -19,3 +24,46 @@ block allocation when actual writes happen? If nothing else, it never
 does the 'fid->size = new_size' and do the inode update....
 
 ffsSetAttr() is just dangling in the breeze, not wired up at all...
+
+Convert global mutexes to a per-superblock mutex.
+
+Right now, we load exactly one UTF-8 table. Check to see
+if that plays nice with different codepage and iocharset values
+for simultanous mounts of different devices
+
+exfat_rmdir() checks for -EBUSY but ffsRemoveDir() doesn't return it.
+In fact, there's a complete lack of -EBUSY testing anywhere.
+
+There's probably a few missing checks for -EEXIST
+
+check return codes of sync_dirty_buffer()
+
+Why is remove_file doing a num_entries++??
+
+Double check a lot of can't-happen parameter checks (for null pointers for
+things that have only one call site and can't pass a null, etc).
+
+All the DEBUG stuff can probably be tossed, including the ioctl(). Either
+that, or convert to a proper fault-injection system.
+
+exfat_remount does exactly one thing.  Fix to actually deal with remount
+options, particularly handling R/O correctly.  For that matter, allow
+R/O mounts in the first place.
+
+Figure out why the VFAT code used multi_sector_(read|write) but the
+exfat code doesn't use it. The difference matters on SSDs with wear leveling.
+
+exfat_fat_sync(), exfat_buf_sync(), and sync_alloc_bitmap()
+aren't called anyplace....
+
+Create helper function for exfat_set_entry_time() and exfat_set_entry_type()
+because it's sort of ugly to be calling the same functionn directly and
+other code calling through the fs_func struc ponters...
+
+clean up the remaining vol_type checks, which are of two types:
+some are ?: operators with magic numbers, and the rest are places
+where we're doing stuff with '.' and '..'.
+
+Patches to:
+	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+	Valdis Kletnieks <valdis.kletnieks@vt.edu>