Inode-based file systems (ext4) in Operating Systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary role of an inode in ext4 file systems?

In the ext4 file system, what does an inode mainly store?

A The actual content of the file

B Metadata about a file such as permissions, ownership, and file size

C The file name and directory path

D The backup copy of the file data

💡 Hint

Think about what information is needed to manage a file without storing its name or content.

An inode stores metadata about a file, including permissions, ownership, timestamps, and pointers to the file's data blocks. It does not store the file name or the actual content.

📋 Factual

intermediate

How does ext4 locate a file's data on disk?

Which structure in ext4 points to the actual data blocks of a file?

A The inode contains pointers to the data blocks

B The superblock contains pointers to the data blocks

C The directory entry contains pointers to the data blocks

D The journal contains pointers to the data blocks

💡 Hint

Consider where the file system stores the location of file content.

The inode holds pointers to the data blocks where the file's actual content is stored. Directory entries only map file names to inode numbers.

🔍 Analysis

advanced

Why does ext4 use indirect pointers in inodes?

Ext4 inodes have direct, single indirect, double indirect, and triple indirect pointers. Why are indirect pointers used?

A To allow files to be larger than what direct pointers alone can address

B To speed up file access by storing data in multiple places

C To store file names within the inode

D To keep a backup of file data in case of corruption

💡 Hint

Think about file size limits and how pointers can extend addressing capacity.

Direct pointers can only address a limited number of blocks. Indirect pointers add layers of referencing, allowing the file system to handle very large files by pointing to blocks that themselves contain pointers.

❓ Comparison

advanced

Difference between inode number and file name in ext4

Which statement correctly describes the relationship between inode numbers and file names in ext4?

A Inode numbers are only used for directories, not files

B Inode numbers store file names directly inside the inode structure

C File names and inode numbers are the same and interchangeable

D File names are stored in directory entries that map to inode numbers; inode numbers do not store file names

💡 Hint

Consider how the file system links names to metadata.

In ext4, directory entries hold file names and link them to inode numbers. The inode itself does not contain the file name but stores metadata and pointers to data.

❓ Reasoning

expert

What happens if an inode is deleted but directory entry remains?

In ext4, if an inode is deleted but the directory entry pointing to it is not removed, what is the likely outcome?

A The inode is automatically restored by the file system

B The file content remains accessible normally

C The directory entry points to invalid data, causing file access errors

D The file system merges the inode with another file's inode

💡 Hint

Think about what happens when metadata is missing but references remain.

If the inode is deleted but the directory entry still exists, the directory entry points to a non-existent inode. This causes errors when trying to access the file because the metadata and data pointers are missing.