EXTFS LIST ORPHANED INODES UPDATE

This makes it easy to have multiple names refer to the same inode number. The data is not stored with the name only the inode number of the data is stored with the name.

Each file name is paired with just the inode number that matches the file data that goes with that name. The names of files are stored on disk in a separate directory. The file data is given a unique number, called an index node or inode number, and the file data is stored on disk using only that number (not the name). To make multiple names possible, in Unix/Linux the file data is stored in a different place than the file name. You can edit the single copy of the file data using either pathname the changes are done to the single copy of the file data that is accessed by either name.ġ.2 File data is stored by number in inodes Index Unix/Linux makes this easy by allowing you to make the pathnames mom/letter and recipies/cookie be two names for the same file data. You only want one file with two ways of accessing it. If mom sends you an updated recipe, you don’t want to have to remember to edit two different files to make the change. You might want to have a letter from your mother containing a chocolate chip cookie recipe filed under both your mom directory and your recipies directory, but you don’t want to have two copies of the file.

EXTFS LIST ORPHANED INODES UPDATE

You can now update the program without having to remember to give new copies to anyone. Instead, you let them hard-link to your program so that there is only one copy of the program with two names. You don’t want to give them a copy of the program, since if you update the program they won’t get the updated version. You want to give someone access to some program you wrote. You create a hard link to the database, so that even when the database is removed by your program the data is still available using the other name and can be instantly restored for the next test. Since the database is 10GB, you don’t want to have to create a 10GB copy of the database every time for testing. The program compresses the database into a new file, then removes the uncompressed database.

You’re working on a database compression routine. You don’t want three copies of all your music files, so you create hard links to have only one copy, stored with names in three directories. You might store tunes by artist, genre, and mood.

12 File System Damage – Orphans and Lost+FoundĪ feature of most Unix/Linux file systems is the ability to have two or more names for the same file data.

10 Example – Files, Directories, and Inodes.

9.1 Each subdirectory adds one to the link count.

9 An empty directory has a link count of two.

7 Linking, Moving, and Removing are directory operations: ln, mv, rm.

6.2 Removing names: decreasing the link count.

6.1 Link count: counting the names for the inode.

6 Hard links: manipulating names for inodes using ln and rm.

5.1 Directories holding file names have different permissions than file data.

5 File attributes are kept with the data inode.

1.2 File data is stored by number in inodes.

Allen – – Winter 2013 - January to April 2013 - Updated 01:36 EST Hard links and Unix/Linux file system index nodes (inodes) Hard links and Unix/Linux file system index nodes (inodes)

Extfs list orphaned inodes