fs/ramfs/inode.c

Source file repositories/reference/linux-study-clean/fs/ramfs/inode.c

File Facts

System
Linux kernel
Corpus path
fs/ramfs/inode.c
Extension
.c
Size
7676 bytes
Lines
330
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ramfs_mount_opts {
	umode_t mode;
};

struct ramfs_fs_info {
	struct ramfs_mount_opts mount_opts;
};

#define RAMFS_DEFAULT_MODE	0755

static const struct super_operations ramfs_ops;
static const struct inode_operations ramfs_dir_inode_operations;

struct inode *ramfs_get_inode(struct super_block *sb,
				const struct inode *dir, umode_t mode, dev_t dev)
{
	struct inode * inode = new_inode(sb);

	if (inode) {
		inode->i_ino = get_next_ino();
		inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
		inode->i_mapping->a_ops = &ram_aops;
		mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
		mapping_set_unevictable(inode->i_mapping);
		simple_inode_init_ts(inode);
		switch (mode & S_IFMT) {
		default:
			init_special_inode(inode, mode, dev);
			break;
		case S_IFREG:
			inode->i_op = &ramfs_file_inode_operations;
			inode->i_fop = &ramfs_file_operations;
			break;
		case S_IFDIR:
			inode->i_op = &ramfs_dir_inode_operations;
			inode->i_fop = &simple_dir_operations;

			/* directory inodes start off with i_nlink == 2 (for "." entry) */
			inc_nlink(inode);
			break;
		case S_IFLNK:
			inode->i_op = &page_symlink_inode_operations;
			inode_nohighmem(inode);
			break;
		}
	}
	return inode;
}

/*
 * File creation. Allocate an inode, and we're done..
 */
/* SMP-safe */
static int
ramfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
	    struct dentry *dentry, umode_t mode, dev_t dev)
{
	struct inode * inode = ramfs_get_inode(dir->i_sb, dir, mode, dev);
	int error = -ENOSPC;

	if (inode) {
		error = security_inode_init_security(inode, dir,
						     &dentry->d_name, NULL,
						     NULL);
		if (error) {
			iput(inode);
			goto out;
		}

		d_make_persistent(dentry, inode);
		error = 0;
		inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
	}
out:
	return error;
}

static struct dentry *ramfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
				 struct dentry *dentry, umode_t mode)
{
	int retval = ramfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFDIR, 0);
	if (!retval)
		inc_nlink(dir);
	return ERR_PTR(retval);
}

static int ramfs_create(struct mnt_idmap *idmap, struct inode *dir,
			struct dentry *dentry, umode_t mode, bool excl)
{
	return ramfs_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0);

Annotation

Implementation Notes