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;
+}