fs/statfs.c

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

File Facts

System
Linux kernel
Corpus path
fs/statfs.c
Extension
.c
Size
9936 bytes
Lines
406
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: syscall or user/kernel boundary
Status
core 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

SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
{
	struct kstatfs st;
	int error = user_statfs(pathname, &st);
	if (!error)
		error = do_statfs_native(&st, buf);
	return error;
}

SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
{
	struct kstatfs st;
	int error;
	if (sz != sizeof(*buf))
		return -EINVAL;
	error = user_statfs(pathname, &st);
	if (!error)
		error = do_statfs64(&st, buf);
	return error;
}

SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
{
	struct kstatfs st;
	int error = fd_statfs(fd, &st);
	if (!error)
		error = do_statfs_native(&st, buf);
	return error;
}

SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
{
	struct kstatfs st;
	int error;

	if (sz != sizeof(*buf))
		return -EINVAL;

	error = fd_statfs(fd, &st);
	if (!error)
		error = do_statfs64(&st, buf);
	return error;
}

static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
{
	struct super_block *s = user_get_super(dev, false);
	int err;
	if (!s)
		return -EINVAL;

	err = statfs_by_dentry(s->s_root, sbuf);
	drop_super(s);
	return err;
}

SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
	struct ustat tmp;
	struct kstatfs sbuf;
	int err = vfs_ustat(new_decode_dev(dev), &sbuf);
	if (err)
		return err;

	memset(&tmp,0,sizeof(struct ustat));
	tmp.f_tfree = sbuf.f_bfree;
	if (IS_ENABLED(CONFIG_ARCH_32BIT_USTAT_F_TINODE))
		tmp.f_tinode = min_t(u64, sbuf.f_ffree, UINT_MAX);
	else
		tmp.f_tinode = sbuf.f_ffree;

	return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
}

#ifdef CONFIG_COMPAT
static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf)
{
	struct compat_statfs buf;
	if (sizeof ubuf->f_blocks == 4) {
		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
			return -EOVERFLOW;
		/* f_files and f_ffree may be -1; it's okay
		 * to stuff that into 32 bits */
		if (kbuf->f_files != 0xffffffffffffffffULL
		 && (kbuf->f_files & 0xffffffff00000000ULL))
			return -EOVERFLOW;
		if (kbuf->f_ffree != 0xffffffffffffffffULL
		 && (kbuf->f_ffree & 0xffffffff00000000ULL))
			return -EOVERFLOW;

Annotation

Implementation Notes