FSCHECK

File System checker for xv6

Usage :

gcc -Wall -Werror fcheck.c -o fcheck

Conditions

SI No	Condition	Error Message
1	Each inode is either unallocated or one of the valid types (T_FILE, T_DIR, T_DEV)	ERROR: bad inode.
2	For in-use inodes, each block address that is used by the inode is valid	ERROR: bad direct address in inode. ERROR: bad indirect address in inode.
3	Root directory exists, its inode number is 1, and the parent of the root directory is itself	ERROR: root directory does not exist.
4	Each directory contains . and .. entries, and the . entry points to the directory itself	ERROR: directory not properly formatted.
5	For in-use inodes, each block address in use is also marked in use in he bitmap	ERROR: address used by inode but marked free in bitmap.
6	For blocks marked in-use in bitmap, the block should actually be in-use in an inode or indirect block somewhere	ERROR: bitmap marks block in use but it is not in use.
7	For in-use inodes, each direct address in use is only use	ERROR: direct address used more than once.
8	For in-use inodes, each indirect address in use is only used once	ERROR: indirect address used more than once.
9	For all inodes marked in use, each must be referred to in at least one directory	ERROR: inode marked use but not found in a directory.
10	For each inode number that is referred to in a valid directory, it is actually marked in use	ERROR: inode referred to in directory
but marked free.
11	Reference counts (number of links) for regular files match the number of times file is referred to in directories (i.e., hard links work correctly)	ERROR: bad reference count for file.
12	No extra links allowed for directories (each directory only appears in one other directory)	ERROR: directory appears more than once in file system.