Linux File Systems
- A collection of file system is reasonable and effective file and directory hierarchy of the organization
- Everything is file is one of the basic philosophy of Unix / Linux is
- Regular file , directory , character devices , block devices , sockets , etc. in Unix / Linux is a file in
- Different types of file are operated by the same API thereof
- Unix / Linux allows different file systems coexist as ext 2 ext 3 ext 4, xfs, btrfs etc.
- Through a unified file I / O system can be of any file system API calls to operate without regard to the specific in its file system format
- File operations can be executed across file systems
linux system and windows system differences:
Linux file system architecture:
- The virtual file system is a software layer in the Linux kernel internal implementation of the abstract file system allows the coexistence of different file systems to provide external uniform application file system interface
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In order to be able to support different file system VFS defines all file systems support basic, abstract interfaces and data structures
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The actual file system implementation-defined abstract VFS interface and data structure itself, such as files, directories and other concepts in
keeping with the formal definition of VFS's consistent unified interface and data structure hides the implementation details
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Superblock super block data structure for storing control information for the file system. Description file system
state, file system type, size, number of blocks, the number of inodes and the like stored in a particular disk sector. -
Inode inode a basic data structure for storing information file package metadata file
size containing such file owner, creation time, disk location. -
Directory entry dentry directory is used to receive the file directory can contain subdirectories nested layers to form a file path.
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File object file a set series of information items with a full sense logically.
The data structure VFS - Superblock is used to describe information about the entire file system. Each of these has its own particular super block
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VFS superblock various specific file system created in the installation and is automatically deleted when the data structure is unloaded super_block
- All the super block object linked together to form a bidirectional ring linked list
- All file system data structure of the information processing documents are placed in the called inode the inode
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Inode specific file system is stored on disk is a static structure, to use it, must be loaded into memory
to fill in the VFS inode, therefore, also called VFS inode is dynamic node - File name can be changed at any time, but the file inode is unique and with the existence of the file exists
- Each of the inode size is typically 128 bytes or 256 bytes
Linux file system directory structure:
