ufs2: Fix inode retrieval

The code multiplied fragno by MINBSIZE instead on fragment size.
Moreover IsDirectory and IsSymlink were called before inode was read.

Change-Id: I9e62007c900fb4376812f8ebef508a3f8a8f619b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6848
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

ufs2: Implementing read function

Attempting to read data from direct blocks and single indirect
blocks even if the data stored is not in continous blocks and
DirectoryIterator now uses ReadAt to iterate through directories.

Change-Id: I8156aba53782da8c2bb4481db611ae26d8881b35
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3088
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

ufs2: implementing open_dir and read_dir function

Root directory is read sucessfully.

Change-Id: I8bdc8c1a52edb679a6cb4b5f70e7f42eb2b2c8f1
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2907
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

ufs2: Implementing read_stat function and fs_info

Change-Id: I337c53c017f00f480af7ac94a5774b39eb5255db
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2773
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

ufs2: Super block is detected successfully.

Change-Id: I5e99b889399fa2d7f477efb547a5923c2c79a6f9
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2658
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

ufs2: Add superblock, volume, identify() and mount()

Change-Id: I27a492145fe1a365ceea6d172e332167513f5c3b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2381
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>