clean statfs-like syscalls up

New helpers: user_statfs() and fd_statfs(), taking userland pathname and
descriptor resp. and filling struct kstatfs.  Syscalls of statfs family
(native, compat and foreign - osf and hpux on alpha and parisc resp.)
switched to those.  Removes some boilerplate code, simplifies cleanup
on errors...

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

5 files changed, 123 insertions, 204 deletions

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index fe698b5045e9..376f22130791 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -230,44 +230,24 @@ linux_to_osf_statfs(struct kstatfs *linux_stat, struct osf_statfs __user *osf_st
         return copy_to_user(osf_stat, &tmp_stat, bufsiz) ? -EFAULT : 0;
 }
 
-static int
-do_osf_statfs(struct path *path, struct osf_statfs __user *buffer,
-              unsigned long bufsiz)
+SYSCALL_DEFINE3(osf_statfs, const char __user *, pathname,
+                struct osf_statfs __user *, buffer, unsigned long, bufsiz)
 {
         struct kstatfs linux_stat;
-        int error = vfs_statfs(path, &linux_stat);
+        int error = user_statfs(pathname, &linux_stat);
         if (!error)
                 error = linux_to_osf_statfs(&linux_stat, buffer, bufsiz);
         return error;   
 }
 
-SYSCALL_DEFINE3(osf_statfs, const char __user *, pathname,
-                struct osf_statfs __user *, buffer, unsigned long, bufsiz)
-{
-        struct path path;
-        int retval;
-
-        retval = user_path(pathname, &path);
-        if (!retval) {
-                retval = do_osf_statfs(&path, buffer, bufsiz);
-                path_put(&path);
-        }
-        return retval;
-}
-
 SYSCALL_DEFINE3(osf_fstatfs, unsigned long, fd,
                 struct osf_statfs __user *, buffer, unsigned long, bufsiz)
 {
-        struct file *file;
-        int retval;
-
-        retval = -EBADF;
-        file = fget(fd);
-        if (file) {
-                retval = do_osf_statfs(&file->f_path, buffer, bufsiz);
-                fput(file);
-        }
-        return retval;
+        struct kstatfs linux_stat;
+        int error = fd_statfs(fd, &linux_stat);
+        if (!error)
+                error = linux_to_osf_statfs(&linux_stat, buffer, bufsiz);
+        return error;
 }
 
 /*
diff --git a/arch/parisc/hpux/sys_hpux.c b/arch/parisc/hpux/sys_hpux.c
index 30394081d9b6..6ab9580b0b00 100644
--- a/arch/parisc/hpux/sys_hpux.c
+++ b/arch/parisc/hpux/sys_hpux.c
@@ -185,26 +185,21 @@ struct hpux_statfs {
      int16_t f_pad;
 };
 
-static int do_statfs_hpux(struct path *path, struct hpux_statfs *buf)
+static int do_statfs_hpux(struct kstatfs *st, struct hpux_statfs __user *p)
 {
-        struct kstatfs st;
-        int retval;
-        
-        retval = vfs_statfs(path, &st);
-        if (retval)
-                return retval;
-
-        memset(buf, 0, sizeof(*buf));
-        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[0] = st.f_fsid.val[0];
-        buf->f_fsid[1] = st.f_fsid.val[1];
-
+        struct hpux_statfs buf;
+        memset(&buf, 0, sizeof(buf));
+        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[0] = st->f_fsid.val[0];
+        buf.f_fsid[1] = st->f_fsid.val[1];
+        if (copy_to_user(p, &buf, sizeof(buf)))
+                return -EFAULT;
         return 0;
 }
 
@@ -212,35 +207,19 @@ static int do_statfs_hpux(struct path *path, struct hpux_statfs *buf)
 asmlinkage long hpux_statfs(const char __user *pathname,
                                                 struct hpux_statfs __user *buf)
 {
-        struct path path;
-        int error;
-
-        error = user_path(pathname, &path);
-        if (!error) {
-                struct hpux_statfs tmp;
-                error = do_statfs_hpux(&path, &tmp);
-                if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                        error = -EFAULT;
-                path_put(&path);
-        }
+        struct kstatfs st;
+        int error = user_statfs(pathname, &st);
+        if (!error)
+                error = do_statfs_hpux(&st, buf);
         return error;
 }
 
 asmlinkage long hpux_fstatfs(unsigned int fd, struct hpux_statfs __user * buf)
 {
-        struct file *file;
-        struct hpux_statfs tmp;
-        int error;
-
-        error = -EBADF;
-        file = fget(fd);
-        if (!file)
-                goto out;
-        error = do_statfs_hpux(&file->f_path, &tmp);
-        if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                error = -EFAULT;
-        fput(file);
- out:
+        struct kstatfs st;
+        int error = fd_statfs(fd, &st);
+        if (!error)
+                error = do_statfs_hpux(&st, buf);
         return error;
 }
 
diff --git a/fs/compat.c b/fs/compat.c
index 691c3fd8ce1d..a071775f3bb3 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -262,35 +262,19 @@ static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *
  */
 asmlinkage long compat_sys_statfs(const char __user *pathname, struct compat_statfs __user *buf)
 {
-        struct path path;
-        int error;
-
-        error = user_path(pathname, &path);
-        if (!error) {
-                struct kstatfs tmp;
-                error = vfs_statfs(&path, &tmp);
-                if (!error)
-                        error = put_compat_statfs(buf, &tmp);
-                path_put(&path);
-        }
+        struct kstatfs tmp;
+        int error = user_statfs(pathname, &tmp);
+        if (!error)
+                error = put_compat_statfs(buf, &tmp);
         return error;
 }
 
 asmlinkage long compat_sys_fstatfs(unsigned int fd, struct compat_statfs __user *buf)
 {
-        struct file * file;
         struct kstatfs tmp;
-        int error;
-
-        error = -EBADF;
-        file = fget(fd);
-        if (!file)
-                goto out;
-        error = vfs_statfs(&file->f_path, &tmp);
+        int error = fd_statfs(fd, &tmp);
         if (!error)
                 error = put_compat_statfs(buf, &tmp);
-        fput(file);
-out:
         return error;
 }
 
@@ -329,41 +313,29 @@ static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstat
 
 asmlinkage long compat_sys_statfs64(const char __user *pathname, compat_size_t sz, struct compat_statfs64 __user *buf)
 {
-        struct path path;
+        struct kstatfs tmp;
         int error;
 
         if (sz != sizeof(*buf))
                 return -EINVAL;
 
-        error = user_path(pathname, &path);
-        if (!error) {
-                struct kstatfs tmp;
-                error = vfs_statfs(&path, &tmp);
-                if (!error)
-                        error = put_compat_statfs64(buf, &tmp);
-                path_put(&path);
-        }
+        error = user_statfs(pathname, &tmp);
+        if (!error)
+                error = put_compat_statfs64(buf, &tmp);
         return error;
 }
 
 asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user *buf)
 {
-        struct file * file;
         struct kstatfs tmp;
         int error;
 
         if (sz != sizeof(*buf))
                 return -EINVAL;
 
-        error = -EBADF;
-        file = fget(fd);
-        if (!file)
-                goto out;
-        error = vfs_statfs(&file->f_path, &tmp);
+        error = fd_statfs(fd, &tmp);
         if (!error)
                 error = put_compat_statfs64(buf, &tmp);
-        fput(file);
-out:
         return error;
 }
 
diff --git a/fs/statfs.c b/fs/statfs.c
index 30ea8c8a996b..8244924dec55 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -73,149 +73,135 @@ int vfs_statfs(struct path *path, struct kstatfs *buf)
 }
 EXPORT_SYMBOL(vfs_statfs);
 
-static int do_statfs_native(struct path *path, struct statfs *buf)
+int user_statfs(const char __user *pathname, struct kstatfs *st)
 {
-        struct kstatfs st;
-        int retval;
+        struct path path;
+        int error = user_path(pathname, &path);
+        if (!error) {
+                error = vfs_statfs(&path, st);
+                path_put(&path);
+        }
+        return error;
+}
 
-        retval = vfs_statfs(path, &st);
-        if (retval)
-                return retval;
+int fd_statfs(int fd, struct kstatfs *st)
+{
+        struct file *file = fget(fd);
+        int error = -EBADF;
+        if (file) {
+                error = vfs_statfs(&file->f_path, st);
+                fput(file);
+        }
+        return error;
+}
 
-        if (sizeof(*buf) == sizeof(st))
-                memcpy(buf, &st, sizeof(st));
+static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
+{
+        struct statfs buf;
+
+        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) &
+                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))
+                        if (st->f_files != -1 &&
+                            (st->f_files & 0xffffffff00000000ULL))
                                 return -EOVERFLOW;
-                        if (st.f_ffree != -1 &&
-                            (st.f_ffree & 0xffffffff00000000ULL))
+                        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;
-                buf->f_flags = st.f_flags;
-                memset(buf->f_spare, 0, sizeof(buf->f_spare));
+                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;
+                buf.f_flags = st->f_flags;
+                memset(buf.f_spare, 0, sizeof(buf.f_spare));
         }
+        if (copy_to_user(p, &buf, sizeof(buf)))
+                return -EFAULT;
         return 0;
 }
 
-static int do_statfs64(struct path *path, struct statfs64 *buf)
+static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
 {
-        struct kstatfs st;
-        int retval;
-
-        retval = vfs_statfs(path, &st);
-        if (retval)
-                return retval;
-
-        if (sizeof(*buf) == sizeof(st))
-                memcpy(buf, &st, sizeof(st));
+        struct statfs64 buf;
+        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;
-                buf->f_flags = st.f_flags;
-                memset(buf->f_spare, 0, sizeof(buf->f_spare));
+                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;
+                buf.f_flags = st->f_flags;
+                memset(buf.f_spare, 0, sizeof(buf.f_spare));
         }
+        if (copy_to_user(p, &buf, sizeof(buf)))
+                return -EFAULT;
         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 = do_statfs_native(&path, &tmp);
-                if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                        error = -EFAULT;
-                path_put(&path);
-        }
+        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 path path;
-        long error;
-
+        struct kstatfs st;
+        int error;
         if (sz != sizeof(*buf))
                 return -EINVAL;
-        error = user_path(pathname, &path);
-        if (!error) {
-                struct statfs64 tmp;
-                error = do_statfs64(&path, &tmp);
-                if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                        error = -EFAULT;
-                path_put(&path);
-        }
+        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 file *file;
-        struct statfs tmp;
-        int error;
-
-        error = -EBADF;
-        file = fget(fd);
-        if (!file)
-                goto out;
-        error = do_statfs_native(&file->f_path, &tmp);
-        if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                error = -EFAULT;
-        fput(file);
-out:
+        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 file *file;
-        struct statfs64 tmp;
+        struct kstatfs st;
         int error;
 
         if (sz != sizeof(*buf))
                 return -EINVAL;
 
-        error = -EBADF;
-        file = fget(fd);
-        if (!file)
-                goto out;
-        error = do_statfs64(&file->f_path, &tmp);
-        if (!error && copy_to_user(buf, &tmp, sizeof(tmp)))
-                error = -EFAULT;
-        fput(file);
-out:
+        error = fd_statfs(fd, &st);
+        if (!error)
+                error = do_statfs64(&st, buf);
         return error;
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index bf5c3c896072..b7178b05cf3a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1874,6 +1874,8 @@ extern void drop_collected_mounts(struct vfsmount *);
 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
                           struct vfsmount *);
 extern int vfs_statfs(struct path *, struct kstatfs *);
+extern int user_statfs(const char __user *, struct kstatfs *);
+extern int fd_statfs(int, struct kstatfs *);
 extern int statfs_by_dentry(struct dentry *, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);