fs: refactor do_mount
Factor out a path_mount helper that takes a struct path * instead of the
actual file name. This will allow to convert the init and devtmpfs code
to properly mount based on a kernel pointer instead of relying on the
implicit set_fs(KERNEL_DS) during early init.
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/namespace.c b/fs/namespace.c
index f30ed40..6f8234f 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3115,12 +3115,11 @@ char *copy_mount_string(const void __user *data)
* Therefore, if this magic number is present, it carries no information
* and must be discarded.
*/
-long do_mount(const char *dev_name, const char __user *dir_name,
+static int path_mount(const char *dev_name, struct path *path,
const char *type_page, unsigned long flags, void *data_page)
{
- struct path path;
unsigned int mnt_flags = 0, sb_flags;
- int retval = 0;
+ int ret;
/* Discard magic */
if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
@@ -3133,19 +3132,13 @@ long do_mount(const char *dev_name, const char __user *dir_name,
if (flags & MS_NOUSER)
return -EINVAL;
- /* ... and get the mountpoint */
- retval = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path);
- if (retval)
- return retval;
-
- retval = security_sb_mount(dev_name, &path,
- type_page, flags, data_page);
- if (!retval && !may_mount())
- retval = -EPERM;
- if (!retval && (flags & SB_MANDLOCK) && !may_mandlock())
- retval = -EPERM;
- if (retval)
- goto dput_out;
+ ret = security_sb_mount(dev_name, path, type_page, flags, data_page);
+ if (ret)
+ return ret;
+ if (!may_mount())
+ return -EPERM;
+ if ((flags & SB_MANDLOCK) && !may_mandlock())
+ return -EPERM;
/* Default to relatime unless overriden */
if (!(flags & MS_NOATIME))
@@ -3172,7 +3165,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
MS_STRICTATIME)) == 0)) {
mnt_flags &= ~MNT_ATIME_MASK;
- mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK;
+ mnt_flags |= path->mnt->mnt_flags & MNT_ATIME_MASK;
}
sb_flags = flags & (SB_RDONLY |
@@ -3185,22 +3178,32 @@ long do_mount(const char *dev_name, const char __user *dir_name,
SB_I_VERSION);
if ((flags & (MS_REMOUNT | MS_BIND)) == (MS_REMOUNT | MS_BIND))
- retval = do_reconfigure_mnt(&path, mnt_flags);
- else if (flags & MS_REMOUNT)
- retval = do_remount(&path, flags, sb_flags, mnt_flags,
- data_page);
- else if (flags & MS_BIND)
- retval = do_loopback(&path, dev_name, flags & MS_REC);
- else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
- retval = do_change_type(&path, flags);
- else if (flags & MS_MOVE)
- retval = do_move_mount_old(&path, dev_name);
- else
- retval = do_new_mount(&path, type_page, sb_flags, mnt_flags,
- dev_name, data_page);
-dput_out:
+ return do_reconfigure_mnt(path, mnt_flags);
+ if (flags & MS_REMOUNT)
+ return do_remount(path, flags, sb_flags, mnt_flags, data_page);
+ if (flags & MS_BIND)
+ return do_loopback(path, dev_name, flags & MS_REC);
+ if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
+ return do_change_type(path, flags);
+ if (flags & MS_MOVE)
+ return do_move_mount_old(path, dev_name);
+
+ return do_new_mount(path, type_page, sb_flags, mnt_flags, dev_name,
+ data_page);
+}
+
+long do_mount(const char *dev_name, const char __user *dir_name,
+ const char *type_page, unsigned long flags, void *data_page)
+{
+ struct path path;
+ int ret;
+
+ ret = user_path_at(AT_FDCWD, dir_name, LOOKUP_FOLLOW, &path);
+ if (ret)
+ return ret;
+ ret = path_mount(dev_name, &path, type_page, flags, data_page);
path_put(&path);
- return retval;
+ return ret;
}
static struct ucounts *inc_mnt_namespaces(struct user_namespace *ns)