Take statfs variants to fs/statfs.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 196 insertions, 0 deletions

diff --git a/fs/statfs.c b/fs/statfs.c
new file mode 100644
index 000000000000..4ef021f3b612
--- /dev/null
+++ b/fs/statfs.c
@@ -0,0 +1,196 @@
+#include <linux/syscalls.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/namei.h>
+#include <linux/statfs.h>
+#include <linux/security.h>
+#include <linux/uaccess.h>
+
+int vfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	int retval = -ENODEV;
+
+	if (dentry) {
+		retval = -ENOSYS;
+		if (dentry->d_sb->s_op->statfs) {
+			memset(buf, 0, sizeof(*buf));
+			retval = security_sb_statfs(dentry);
+			if (retval)
+				return retval;
+			retval = dentry->d_sb->s_op->statfs(dentry, buf);
+			if (retval == 0 && buf->f_frsize == 0)
+				buf->f_frsize = buf->f_bsize;
+		}
+	}
+	return retval;
+}
+
+EXPORT_SYMBOL(vfs_statfs);
+
+static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf)
+{
+	struct kstatfs st;
+	int retval;
+
+	retval = vfs_statfs(dentry, &st);
+	if (retval)
+		return retval;
+
+	if (sizeof(*buf) == sizeof(st))
+		memcpy(buf, &st, sizeof(st));
+	else {
+		if (sizeof buf->f_blocks == 4) {
+			if ((st.f_blocks | st.f_bfree | st.f_bavail |
+			     st.f_bsize | st.f_frsize) &
+			    0xffffffff00000000ULL)
+				return -EOVERFLOW;
+			/*
+			 * f_files and f_ffree may be -1; it's okay to stuff
+			 * that into 32 bits
+			 */
+			if (st.f_files != -1 &&
+			    (st.f_files & 0xffffffff00000000ULL))
+				return -EOVERFLOW;
+			if (st.f_ffree != -1 &&
+			    (st.f_ffree & 0xffffffff00000000ULL))
+				return -EOVERFLOW;
+		}
+
+		buf->f_type = st.f_type;
+		buf->f_bsize = st.f_bsize;
+		buf->f_blocks = st.f_blocks;
+		buf->f_bfree = st.f_bfree;
+		buf->f_bavail = st.f_bavail;
+		buf->f_files = st.f_files;
+		buf->f_ffree = st.f_ffree;
+		buf->f_fsid = st.f_fsid;
+		buf->f_namelen = st.f_namelen;
+		buf->f_frsize = st.f_frsize;
+		memset(buf->f_spare, 0, sizeof(buf->f_spare));
+	}
+	return 0;
+}
+
+static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf)
+{
+	struct kstatfs st;
+	int retval;
+
+	retval = vfs_statfs(dentry, &st);
+	if (retval)
+		return retval;
+
+	if (sizeof(*buf) == sizeof(st))
+		memcpy(buf, &st, sizeof(st));
+	else {
+		buf->f_type = st.f_type;
+		buf->f_bsize = st.f_bsize;
+		buf->f_blocks = st.f_blocks;
+		buf->f_bfree = st.f_bfree;
+		buf->f_bavail = st.f_bavail;
+		buf->f_files = st.f_files;
+		buf->f_ffree = st.f_ffree;
+		buf->f_fsid = st.f_fsid;
+		buf->f_namelen = st.f_namelen;
+		buf->f_frsize = st.f_frsize;
+		memset(buf->f_spare, 0, sizeof(buf->f_spare));
+	}
+	return 0;
+}
+
+SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
+{
+	struct path path;
+	int error;
+
+	error = user_path(pathname, &path);
+	if (!error) {
+		struct statfs tmp;
+		error = vfs_statfs_native(path.dentry, &tmp);
+		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
+			error = -EFAULT;
+		path_put(&path);
+	}
+	return error;
+}
+
+SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
+{
+	struct path path;
+	long error;
+
+	if (sz != sizeof(*buf))
+		return -EINVAL;
+	error = user_path(pathname, &path);
+	if (!error) {
+		struct statfs64 tmp;
+		error = vfs_statfs64(path.dentry, &tmp);
+		if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
+			error = -EFAULT;
+		path_put(&path);
+	}
+	return error;
+}
+
+SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
+{
+	struct file *file;
+	struct statfs tmp;
+	int error;
+
+	error = -EBADF;
+	file = fget(fd);
+	if (!file)
+		goto out;
+	error = vfs_statfs_native(file->f_path.dentry, &tmp);
+	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
+		error = -EFAULT;
+	fput(file);
+out:
+	return error;
+}
+
+SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
+{
+	struct file *file;
+	struct statfs64 tmp;
+	int error;
+
+	if (sz != sizeof(*buf))
+		return -EINVAL;
+
+	error = -EBADF;
+	file = fget(fd);
+	if (!file)
+		goto out;
+	error = vfs_statfs64(file->f_path.dentry, &tmp);
+	if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
+		error = -EFAULT;
+	fput(file);
+out:
+	return error;
+}
+
+SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
+{
+	struct super_block *s;
+	struct ustat tmp;
+	struct kstatfs sbuf;
+	int err;
+
+	s = user_get_super(new_decode_dev(dev));
+	if (!s)
+		return -EINVAL;
+
+	err = vfs_statfs(s->s_root, &sbuf);
+	drop_super(s);
+	if (err)
+		return err;
+
+	memset(&tmp,0,sizeof(struct ustat));
+	tmp.f_tfree = sbuf.f_bfree;
+	tmp.f_tinode = sbuf.f_ffree;
+
+	return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
+}