dentry

on. Under Linux, you can view the Inode information for a file by using the "Ls-li" command. The size is 2048 bytes, the Inode block is equivalent to the directory, from the table of contents can know the location of each chapter; Block: The actual record of the contents of the file, if the file is too large, will occupy more than block. In order to improve the efficiency of directory Access, Linux also provides the dentry structure of the corres

most basic unit of the file system and is the bridge of any subdirectory or file connected to the file system. Each subdirectory and file has only one inode block.It contains information about the basic properties of files in the file system (length of file, creation and modification time, permissions, affiliation), location of the data stored, and so on. Under Linux, you can view the Inode information for a file by using the "Ls-li" command. Hard connections and source files have the same inod

disk block device and does not delve into it. The Register_filesystem function registers the Sysfs file system with the system, where Sysfs_fs_type is a File_system_type object that describes the Sysfs file system information: struct file_system_type {* * name/const char *name; /* Specify some features of the file system */int fs_flags; /* File system load function */struct Dentry * (*mount) (struct file_system_type *, int, const char *, void

EXT3 Mount Principle In essence, the process of EXT3 mount is actually the process by which the inode is substituted. For example, the/DEV/SDB block device is mount to the/mnt/alan directory. The problem with the mount process is to screen out the inode that the/mnt/alan dentry directory entry points to, and then relocate to the Inode index node that/DEV/SDB represents. In the absence of an analysis of the Linux VFS Mount code, my idea is to modify t

necessarily close the file, but reduces the reference count, close the file only when the reference count is reduced to 0. For general files opened on the same file system, the steps and methods for file operations such as read and write should be the same, and the called functions should be the same, therefore, the file struct of the three open files in the figure points to the same file_operations struct. If you open a character device file, its read, writeThe operation must be different from

, type, flag) the input parameter protocol family type, stream socket, datagram socket, and other Mount corresponding processing function sets. Let's look at the work of sock_map_fd (sock, flags (o_cloexec | o_nonblock ); Int sock_map_fd (struct socket * sock, int flags) { Struct file * newfile; Int FD = sock_alloc_fd ( newfile, flags); assign the file number and structure to the socket. If (likely (FD> = 0 )){Int err = sock_attach_fd (sock, newfile, flags); associate the socket with the file

Linux-2.6 file opening process involves data structure analysis: Link: http://blog.csdn.net/ordeder/article/details/24420637User level The file is opened in the following structure: Fd = open (path, flag, mode)Kernel layer After the open function is trapped in the kernel space, perform the following operations: The system traverses the path based on the path. In linux, everything is a file, including directories, which are also considered as files. Each file has an entry structure to indicate

and source files have the same inode. Block: The actual record of the contents of the file, if the file is too large, will occupy more than block. In order to improve the efficiency of directory Access, Linux also provides the dentry structure of the corresponding relationship between the expression path and the inode. It describes the path information and connects to the node Inode, which includes various directory information, and also points t

request. The release member in the File_operations struct is used to complete the close request of the user program, which is called release instead of close because it does not necessarily close the file, but reduces the reference count, and only the reference count is reduced to 0 to close the file. For regular files that are open on the same file system, the steps and methods for file operations such as read, write, and so on, should be the same, and the calling function should be the same,

same, therefore, the file structure of the three open files in the figure points to the same file_operation structure. It is different if the opened files are non-conventional files. Each file structure has a pointer to the dentry struct. "dentry" is the abbreviation of directory entry. Parameters passed to functions such as open and stat are a path, for example,/home/orlion/a. inode of the file needs to b

read, write operation must be different from the regular file, not read and write disk data block, but read and write hardware devices, so the file structure should point to the various file_operations structure body, The various file manipulation functions are implemented by the driver of the device.Each file struct has a pointer to the dentry struct, and "Dentry" is an abbreviation for the directory entr

file manipulation functions are implemented by the driver for the device.3.file.dentryEach file struct has a dentry pointer to the struct, and"Dentry" is an abbreviation for directory entry (directory entry) . The open parameters of the function that we pass to, and stat so on, are a path, for example /home/akaedu/a , to find the inode of the file based on the path. in order to reduce the number of reads,

pointer to the dentry struct, and "Dentry" is an abbreviation for the directory entry (directory entry). The arguments we pass to the open, stat, and other functions are a path, such as/home/akaedu/a, where the inode of the file needs to be found based on the path. To reduce the number of reads, the kernel caches the tree structure of the directory, called the Dentry