Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull more vfs updates from Al Viro:
 "Assorted stuff from this cycle.  The big ones here are multilayer
  overlayfs from Miklos and beginning of sorting ->d_inode accesses out
  from David"

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (51 commits)
  autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation
  procfs: fix race between symlink removals and traversals
  debugfs: leave freeing a symlink body until inode eviction
  Documentation/filesystems/Locking: ->get_sb() is long gone
  trylock_super(): replacement for grab_super_passive()
  fanotify: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
  Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
  VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)
  SELinux: Use d_is_positive() rather than testing dentry->d_inode
  Smack: Use d_is_positive() rather than testing dentry->d_inode
  TOMOYO: Use d_is_dir() rather than d_inode and S_ISDIR()
  Apparmor: Use d_is_positive/negative() rather than testing dentry->d_inode
  Apparmor: mediated_filesystem() should use dentry->d_sb not inode->i_sb
  VFS: Split DCACHE_FILE_TYPE into regular and special types
  VFS: Add a fallthrough flag for marking virtual dentries
  VFS: Add a whiteout dentry type
  VFS: Introduce inode-getting helpers for layered/unioned fs environments
  Infiniband: Fix potential NULL d_inode dereference
  posix_acl: fix reference leaks in posix_acl_create
  autofs4: Wrong format for printing dentry
  ...

fs/xfs/xfs_ioctl.c

@@ -287,7 +287,7 @@ xfs_readlink_by_handle(
 		return PTR_ERR(dentry);
 
 	/* Restrict this handle operation to symlinks only. */
-	if (!S_ISLNK(dentry->d_inode->i_mode)) {
+	if (!d_is_symlink(dentry)) {
 		error = -EINVAL;
 		goto out_dput;
 	}

include/linux/dcache.h

@@ -215,13 +215,16 @@ struct dentry_operations {
 #define DCACHE_LRU_LIST			0x00080000
 
 #define DCACHE_ENTRY_TYPE		0x00700000
-#define DCACHE_MISS_TYPE		0x00000000 /* Negative dentry */
-#define DCACHE_DIRECTORY_TYPE		0x00100000 /* Normal directory */
-#define DCACHE_AUTODIR_TYPE		0x00200000 /* Lookupless directory (presumed automount) */
-#define DCACHE_SYMLINK_TYPE		0x00300000 /* Symlink */
-#define DCACHE_FILE_TYPE		0x00400000 /* Other file type */
+#define DCACHE_MISS_TYPE		0x00000000 /* Negative dentry (maybe fallthru to nowhere) */
+#define DCACHE_WHITEOUT_TYPE		0x00100000 /* Whiteout dentry (stop pathwalk) */
+#define DCACHE_DIRECTORY_TYPE		0x00200000 /* Normal directory */
+#define DCACHE_AUTODIR_TYPE		0x00300000 /* Lookupless directory (presumed automount) */
+#define DCACHE_REGULAR_TYPE		0x00400000 /* Regular file type (or fallthru to such) */
+#define DCACHE_SPECIAL_TYPE		0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_SYMLINK_TYPE		0x00600000 /* Symlink (or fallthru to such) */
 
 #define DCACHE_MAY_FREE			0x00800000
+#define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
 
 extern seqlock_t rename_lock;
 
@@ -423,6 +426,16 @@ static inline unsigned __d_entry_type(const struct dentry *dentry)
 	return dentry->d_flags & DCACHE_ENTRY_TYPE;
 }
 
+static inline bool d_is_miss(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+}
+
+static inline bool d_is_whiteout(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
+}
+
 static inline bool d_can_lookup(const struct dentry *dentry)
 {
 	return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
@@ -443,14 +456,25 @@ static inline bool d_is_symlink(const struct dentry *dentry)
 	return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
 }
 
+static inline bool d_is_reg(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
+}
+
+static inline bool d_is_special(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
+}
+
 static inline bool d_is_file(const struct dentry *dentry)
 {
-	return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
+	return d_is_reg(dentry) || d_is_special(dentry);
 }
 
 static inline bool d_is_negative(const struct dentry *dentry)
 {
-	return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+	// TODO: check d_is_whiteout(dentry) also.
+	return d_is_miss(dentry);
 }
 
 static inline bool d_is_positive(const struct dentry *dentry)
@@ -458,10 +482,75 @@ static inline bool d_is_positive(const struct dentry *dentry)
 	return !d_is_negative(dentry);
 }
 
+extern void d_set_fallthru(struct dentry *dentry);
+
+static inline bool d_is_fallthru(const struct dentry *dentry)
+{
+	return dentry->d_flags & DCACHE_FALLTHRU;
+}
+
+
 extern int sysctl_vfs_cache_pressure;
 
 static inline unsigned long vfs_pressure_ratio(unsigned long val)
 {
 	return mult_frac(val, sysctl_vfs_cache_pressure, 100);
 }
+
+/**
+ * d_inode - Get the actual inode of this dentry
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode(const struct dentry *dentry)
+{
+	return dentry->d_inode;
+}
+
+/**
+ * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE()
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode_rcu(const struct dentry *dentry)
+{
+	return ACCESS_ONCE(dentry->d_inode);
+}
+
+/**
+ * d_backing_inode - Get upper or lower inode we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get at the inode that will be used
+ * if this dentry were to be opened as a file.  The inode may be on the upper
+ * dentry or it may be on a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own inodes.
+ */
+static inline struct inode *d_backing_inode(const struct dentry *upper)
+{
+	struct inode *inode = upper->d_inode;
+
+	return inode;
+}
+
+/**
+ * d_backing_dentry - Get upper or lower dentry we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get the dentry of the inode that
+ * will be used if this dentry were opened as a file.  It may be the upper
+ * dentry or it may be a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own dentries.
+ */
+static inline struct dentry *d_backing_dentry(struct dentry *upper)
+{
+	return upper;
+}
+
 #endif	/* __LINUX_DCACHE_H */

mm/shmem.c

@@ -2319,8 +2319,8 @@ static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
 
 static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
 {
-	bool old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
-	bool new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
+	bool old_is_dir = d_is_dir(old_dentry);
+	bool new_is_dir = d_is_dir(new_dentry);
 
 	if (old_dir != new_dir && old_is_dir != new_is_dir) {
 		if (old_is_dir) {

security/apparmor/include/apparmor.h

@@ -112,9 +112,9 @@ static inline unsigned int aa_dfa_null_transition(struct aa_dfa *dfa,
 	return aa_dfa_next(dfa, start, 0);
 }
 
-static inline bool mediated_filesystem(struct inode *inode)
+static inline bool mediated_filesystem(struct dentry *dentry)
 {
-	return !(inode->i_sb->s_flags & MS_NOUSER);
+	return !(dentry->d_sb->s_flags & MS_NOUSER);
 }
 
 #endif /* __APPARMOR_H */

security/apparmor/lsm.c

@@ -226,7 +226,7 @@ static int common_perm_rm(int op, struct path *dir,
 	struct inode *inode = dentry->d_inode;
 	struct path_cond cond = { };
 
-	if (!inode || !dir->mnt || !mediated_filesystem(inode))
+	if (!inode || !dir->mnt || !mediated_filesystem(dentry))
 		return 0;
 
 	cond.uid = inode->i_uid;
@@ -250,7 +250,7 @@ static int common_perm_create(int op, struct path *dir, struct dentry *dentry,
 {
 	struct path_cond cond = { current_fsuid(), mode };
 
-	if (!dir->mnt || !mediated_filesystem(dir->dentry->d_inode))
+	if (!dir->mnt || !mediated_filesystem(dir->dentry))
 		return 0;
 
 	return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
@@ -285,7 +285,7 @@ static int apparmor_path_truncate(struct path *path)
 				  path->dentry->d_inode->i_mode
 	};
 
-	if (!path->mnt || !mediated_filesystem(path->dentry->d_inode))
+	if (!path->mnt || !mediated_filesystem(path->dentry))
 		return 0;
 
 	return common_perm(OP_TRUNC, path, MAY_WRITE | AA_MAY_META_WRITE,
@@ -305,7 +305,7 @@ static int apparmor_path_link(struct dentry *old_dentry, struct path *new_dir,
 	struct aa_profile *profile;
 	int error = 0;
 
-	if (!mediated_filesystem(old_dentry->d_inode))
+	if (!mediated_filesystem(old_dentry))
 		return 0;
 
 	profile = aa_current_profile();
@@ -320,7 +320,7 @@ static int apparmor_path_rename(struct path *old_dir, struct dentry *old_dentry,
 	struct aa_profile *profile;
 	int error = 0;
 
-	if (!mediated_filesystem(old_dentry->d_inode))
+	if (!mediated_filesystem(old_dentry))
 		return 0;
 
 	profile = aa_current_profile();
@@ -346,7 +346,7 @@ static int apparmor_path_rename(struct path *old_dir, struct dentry *old_dentry,
 
 static int apparmor_path_chmod(struct path *path, umode_t mode)
 {
-	if (!mediated_filesystem(path->dentry->d_inode))
+	if (!mediated_filesystem(path->dentry))
 		return 0;
 
 	return common_perm_mnt_dentry(OP_CHMOD, path->mnt, path->dentry, AA_MAY_CHMOD);
@@ -358,7 +358,7 @@ static int apparmor_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 				   path->dentry->d_inode->i_mode
 	};
 
-	if (!mediated_filesystem(path->dentry->d_inode))
+	if (!mediated_filesystem(path->dentry))
 		return 0;
 
 	return common_perm(OP_CHOWN, path, AA_MAY_CHOWN, &cond);
@@ -366,7 +366,7 @@ static int apparmor_path_chown(struct path *path, kuid_t uid, kgid_t gid)
 
 static int apparmor_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
 {
-	if (!mediated_filesystem(dentry->d_inode))
+	if (!mediated_filesystem(dentry))
 		return 0;
 
 	return common_perm_mnt_dentry(OP_GETATTR, mnt, dentry,
@@ -379,7 +379,7 @@ static int apparmor_file_open(struct file *file, const struct cred *cred)
 	struct aa_profile *profile;
 	int error = 0;
 
-	if (!mediated_filesystem(file_inode(file)))
+	if (!mediated_filesystem(file->f_path.dentry))
 		return 0;
 
 	/* If in exec, permission is handled by bprm hooks.
@@ -432,7 +432,7 @@ static int common_file_perm(int op, struct file *file, u32 mask)
 	BUG_ON(!fprofile);
 
 	if (!file->f_path.mnt ||
-	    !mediated_filesystem(file_inode(file)))
+	    !mediated_filesystem(file->f_path.dentry))
 		return 0;
 
 	profile = __aa_current_profile();

security/apparmor/path.c

@@ -114,7 +114,7 @@ static int d_namespace_path(struct path *path, char *buf, int buflen,
 	 *    security_path hooks as a deleted dentry except without an inode
 	 *    allocated.
 	 */
-	if (d_unlinked(path->dentry) && path->dentry->d_inode &&
+	if (d_unlinked(path->dentry) && d_is_positive(path->dentry) &&
 	    !(flags & PATH_MEDIATE_DELETED)) {
 			error = -ENOENT;
 			goto out;

security/inode.c

@@ -203,7 +203,7 @@ void securityfs_remove(struct dentry *dentry)
 	mutex_lock(&parent->d_inode->i_mutex);
 	if (positive(dentry)) {
 		if (dentry->d_inode) {
-			if (S_ISDIR(dentry->d_inode->i_mode))
+			if (d_is_dir(dentry))
 				simple_rmdir(parent->d_inode, dentry);
 			else
 				simple_unlink(parent->d_inode, dentry);

security/selinux/hooks.c

@@ -1799,7 +1799,7 @@ static inline int may_rename(struct inode *old_dir,
 
 	old_dsec = old_dir->i_security;
 	old_isec = old_dentry->d_inode->i_security;
-	old_is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
+	old_is_dir = d_is_dir(old_dentry);
 	new_dsec = new_dir->i_security;
 
 	ad.type = LSM_AUDIT_DATA_DENTRY;
@@ -1822,14 +1822,14 @@ static inline int may_rename(struct inode *old_dir,
 
 	ad.u.dentry = new_dentry;
 	av = DIR__ADD_NAME | DIR__SEARCH;
-	if (new_dentry->d_inode)
+	if (d_is_positive(new_dentry))
 		av |= DIR__REMOVE_NAME;
 	rc = avc_has_perm(sid, new_dsec->sid, SECCLASS_DIR, av, &ad);
 	if (rc)
 		return rc;
-	if (new_dentry->d_inode) {
+	if (d_is_positive(new_dentry)) {
 		new_isec = new_dentry->d_inode->i_security;
-		new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
+		new_is_dir = d_is_dir(new_dentry);
 		rc = avc_has_perm(sid, new_isec->sid,
 				  new_isec->sclass,
 				  (new_is_dir ? DIR__RMDIR : FILE__UNLINK), &ad);

security/smack/smack_lsm.c

@@ -855,7 +855,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 	rc = smk_curacc(isp, MAY_WRITE, &ad);
 	rc = smk_bu_inode(old_dentry->d_inode, MAY_WRITE, rc);
 
-	if (rc == 0 && new_dentry->d_inode != NULL) {
+	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(new_dentry->d_inode);
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
 		rc = smk_curacc(isp, MAY_WRITE, &ad);
@@ -961,7 +961,7 @@ static int smack_inode_rename(struct inode *old_inode,
 	rc = smk_curacc(isp, MAY_READWRITE, &ad);
 	rc = smk_bu_inode(old_dentry->d_inode, MAY_READWRITE, rc);
 
-	if (rc == 0 && new_dentry->d_inode != NULL) {
+	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(new_dentry->d_inode);
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
 		rc = smk_curacc(isp, MAY_READWRITE, &ad);

security/tomoyo/file.c

@@ -905,11 +905,9 @@ int tomoyo_path2_perm(const u8 operation, struct path *path1,
 	    !tomoyo_get_realpath(&buf2, path2))
 		goto out;
 	switch (operation) {
-		struct dentry *dentry;
 	case TOMOYO_TYPE_RENAME:
 	case TOMOYO_TYPE_LINK:
-		dentry = path1->dentry;
-		if (!dentry->d_inode || !S_ISDIR(dentry->d_inode->i_mode))
+		if (!d_is_dir(path1->dentry))
 			break;
 		/* fall through */
 	case TOMOYO_TYPE_PIVOT_ROOT: