autofs4: make autofs type usage explicit

- the type assigned at mount when no type is given is changed
  from 0 to AUTOFS_TYPE_INDIRECT. This was done because 0 and
  AUTOFS_TYPE_INDIRECT were being treated implicitly as the same
  type.

- previously, an offset mount had it's type set to
  AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET but the mount control
  re-implementation needs to be able distinguish all three types.
  So this was changed to make the type setting explicit.

- a type AUTOFS_TYPE_ANY was added for use by the re-implementation
  when checking if a given path is a mountpoint. It's not really a
  type as we use this to ask if a given path is a mountpoint in the
  autofs_dev_ioctl_ismountpoint() function.

- functions to set and test the autofs mount types have been added to
  improve readability and make the type usage explicit.

- the mount type is used from user space for the mount control
  re-implementtion so, for consistency, all the definitions have
  been moved to the user space include file include/linux/auto_fs4.h.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 73 insertions, 21 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index e0f16da00e54..a76803108d06 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -25,8 +25,6 @@
 #define AUTOFS_DEV_IOCTL_IOC_FIRST      (AUTOFS_DEV_IOCTL_VERSION)
 #define AUTOFS_DEV_IOCTL_IOC_COUNT      (AUTOFS_IOC_COUNT - 11)
 
-#define AUTOFS_TYPE_TRIGGER     (AUTOFS_TYPE_DIRECT|AUTOFS_TYPE_OFFSET)
-
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/time.h>
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 0566ff8db4cd..aa3f47293bb8 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -532,7 +532,7 @@ static int autofs_dev_ioctl_expire(struct file *fp,
         how = param->expire.how;
         mnt = fp->f_path.mnt;
 
-        if (sbi->type & AUTOFS_TYPE_TRIGGER)
+        if (autofs_type_trigger(sbi->type))
                 dentry = autofs4_expire_direct(sbi->sb, mnt, sbi, how);
         else
                 dentry = autofs4_expire_indirect(sbi->sb, mnt, sbi, how);
@@ -615,7 +615,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
         param->ismountpoint.out.magic = magic = 0;
 
         if (!fp || param->ioctlfd == -1) {
-                if (type == AUTOFS_TYPE_ANY) {
+                if (autofs_type_any(type)) {
                         struct super_block *sb;
 
                         err = path_lookup(path, LOOKUP_FOLLOW, &nd);
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 4b6fb3f628c0..e3bd50776f9e 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -63,7 +63,7 @@ static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
                 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 
                 /* This is an autofs submount, we can't expire it */
-                if (sbi->type == AUTOFS_TYPE_INDIRECT)
+                if (autofs_type_indirect(sbi->type))
                         goto done;
 
                 /*
@@ -490,7 +490,7 @@ int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
         if (arg && get_user(do_now, arg))
                 return -EFAULT;
 
-        if (sbi->type & AUTOFS_TYPE_TRIGGER)
+        if (autofs_type_trigger(sbi->type))
                 dentry = autofs4_expire_direct(sb, mnt, sbi, do_now);
         else
                 dentry = autofs4_expire_indirect(sb, mnt, sbi, do_now);
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index cfc23e53b6f4..716e12b627b2 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -197,9 +197,9 @@ static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
         seq_printf(m, ",minproto=%d", sbi->min_proto);
         seq_printf(m, ",maxproto=%d", sbi->max_proto);
 
-        if (sbi->type & AUTOFS_TYPE_OFFSET)
+        if (autofs_type_offset(sbi->type))
                 seq_printf(m, ",offset");
-        else if (sbi->type & AUTOFS_TYPE_DIRECT)
+        else if (autofs_type_direct(sbi->type))
                 seq_printf(m, ",direct");
         else
                 seq_printf(m, ",indirect");
@@ -284,13 +284,13 @@ static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
                         *maxproto = option;
                         break;
                 case Opt_indirect:
-                        *type = AUTOFS_TYPE_INDIRECT;
+                        set_autofs_type_indirect(type);
                         break;
                 case Opt_direct:
-                        *type = AUTOFS_TYPE_DIRECT;
+                        set_autofs_type_direct(type);
                         break;
                 case Opt_offset:
-                        *type = AUTOFS_TYPE_OFFSET;
+                        set_autofs_type_offset(type);
                         break;
                 default:
                         return 1;
@@ -338,7 +338,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
         sbi->sb = s;
         sbi->version = 0;
         sbi->sub_version = 0;
-        sbi->type = AUTOFS_TYPE_INDIRECT;
+        set_autofs_type_indirect(&sbi->type);
         sbi->min_proto = 0;
         sbi->max_proto = 0;
         mutex_init(&sbi->wq_mutex);
@@ -380,7 +380,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
         }
 
         root_inode->i_fop = &autofs4_root_operations;
-        root_inode->i_op = sbi->type & AUTOFS_TYPE_TRIGGER ?
+        root_inode->i_op = autofs_type_trigger(sbi->type) ?
                         &autofs4_direct_root_inode_operations :
                         &autofs4_indirect_root_inode_operations;
 
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c
index e02cc8ae5eb3..eeb246845909 100644
--- a/fs/autofs4/waitq.c
+++ b/fs/autofs4/waitq.c
@@ -337,7 +337,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                  * is very similar for indirect mounts except only dentrys
                  * in the root of the autofs file system may be negative.
                  */
-                if (sbi->type & AUTOFS_TYPE_TRIGGER)
+                if (autofs_type_trigger(sbi->type))
                         return -ENOENT;
                 else if (!IS_ROOT(dentry->d_parent))
                         return -ENOENT;
@@ -348,7 +348,7 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                 return -ENOMEM;
 
         /* If this is a direct mount request create a dummy name */
-        if (IS_ROOT(dentry) && sbi->type & AUTOFS_TYPE_TRIGGER)
+        if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
                 qstr.len = sprintf(name, "%p", dentry);
         else {
                 qstr.len = autofs4_getpath(sbi, dentry, &name);
@@ -406,11 +406,11 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
                                 type = autofs_ptype_expire_multi;
                 } else {
                         if (notify == NFY_MOUNT)
-                                type = (sbi->type & AUTOFS_TYPE_TRIGGER) ?
+                                type = autofs_type_trigger(sbi->type) ?
                                         autofs_ptype_missing_direct :
                                          autofs_ptype_missing_indirect;
                         else
-                                type = (sbi->type & AUTOFS_TYPE_TRIGGER) ?
+                                type = autofs_type_trigger(sbi->type) ?
                                         autofs_ptype_expire_direct :
                                         autofs_ptype_expire_indirect;
                 }
diff --git a/include/linux/auto_fs4.h b/include/linux/auto_fs4.h
index 2253716d4b92..55fa478bd639 100644
--- a/include/linux/auto_fs4.h
+++ b/include/linux/auto_fs4.h
@@ -29,10 +29,64 @@
 #define AUTOFS_EXP_IMMEDIATE            1
 #define AUTOFS_EXP_LEAVES               2
 
-#define AUTOFS_TYPE_ANY                 0x0000
-#define AUTOFS_TYPE_INDIRECT            0x0001
-#define AUTOFS_TYPE_DIRECT              0x0002
-#define AUTOFS_TYPE_OFFSET              0x0004
+#define AUTOFS_TYPE_ANY                 0U
+#define AUTOFS_TYPE_INDIRECT            1U
+#define AUTOFS_TYPE_DIRECT              2U
+#define AUTOFS_TYPE_OFFSET              4U
+
+static inline void set_autofs_type_indirect(unsigned int *type)
+{
+        *type = AUTOFS_TYPE_INDIRECT;
+        return;
+}
+
+static inline unsigned int autofs_type_indirect(unsigned int type)
+{
+        return (type == AUTOFS_TYPE_INDIRECT);
+}
+
+static inline void set_autofs_type_direct(unsigned int *type)
+{
+        *type = AUTOFS_TYPE_DIRECT;
+        return;
+}
+
+static inline unsigned int autofs_type_direct(unsigned int type)
+{
+        return (type == AUTOFS_TYPE_DIRECT);
+}
+
+static inline void set_autofs_type_offset(unsigned int *type)
+{
+        *type = AUTOFS_TYPE_OFFSET;
+        return;
+}
+
+static inline unsigned int autofs_type_offset(unsigned int type)
+{
+        return (type == AUTOFS_TYPE_OFFSET);
+}
+
+static inline unsigned int autofs_type_trigger(unsigned int type)
+{
+        return (type == AUTOFS_TYPE_DIRECT || type == AUTOFS_TYPE_OFFSET);
+}
+
+/*
+ * This isn't really a type as we use it to say "no type set" to
+ * indicate we want to search for "any" mount in the
+ * autofs_dev_ioctl_ismountpoint() device ioctl function.
+ */
+static inline void set_autofs_type_any(unsigned int *type)
+{
+        *type = AUTOFS_TYPE_ANY;
+        return;
+}
+
+static inline unsigned int autofs_type_any(unsigned int type)
+{
+        return (type == AUTOFS_TYPE_ANY);
+}
 
 /* Daemon notification packet types */
 enum autofs_notify {