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

Pull vfs pile 3 (of many) from Al Viro:
 "Waiman's conversion of d_path() and bits related to it,
  kern_path_mountpoint(), several cleanups and fixes (exportfs
  one is -stable fodder, IMO).

  There definitely will be more...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  split read_seqretry_or_unlock(), convert d_walk() to resulting primitives
  dcache: Translating dentry into pathname without taking rename_lock
  autofs4 - fix device ioctl mount lookup
  introduce kern_path_mountpoint()
  rename user_path_umountat() to user_path_mountpoint_at()
  take unlazy_walk() into umount_lookup_last()
  Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c
  prune_super(): sb->s_op is never NULL
  exportfs: don't assume that ->iterate() won't feed us too long entries
  afs: get rid of redundant ->d_name.len checks

fs/afs/dir.c

@@ -751,10 +751,6 @@ static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	_enter("{%x:%u},{%s},%ho",
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
 
-	ret = -ENAMETOOLONG;
-	if (dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
@@ -816,10 +812,6 @@ static int afs_rmdir(struct inode *dir, struct dentry *dentry)
 	_enter("{%x:%u},{%s}",
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name);
 
-	ret = -ENAMETOOLONG;
-	if (dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
@@ -936,10 +928,6 @@ static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	_enter("{%x:%u},{%s},%ho,",
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name, mode);
 
-	ret = -ENAMETOOLONG;
-	if (dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
@@ -1005,10 +993,6 @@ static int afs_link(struct dentry *from, struct inode *dir,
 	       dvnode->fid.vid, dvnode->fid.vnode,
 	       dentry->d_name.name);
 
-	ret = -ENAMETOOLONG;
-	if (dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);
@@ -1053,10 +1037,6 @@ static int afs_symlink(struct inode *dir, struct dentry *dentry,
 	       dvnode->fid.vid, dvnode->fid.vnode, dentry->d_name.name,
 	       content);
 
-	ret = -ENAMETOOLONG;
-	if (dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	ret = -EINVAL;
 	if (strlen(content) >= AFSPATHMAX)
 		goto error;
@@ -1127,10 +1107,6 @@ static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	       new_dvnode->fid.vid, new_dvnode->fid.vnode,
 	       new_dentry->d_name.name);
 
-	ret = -ENAMETOOLONG;
-	if (new_dentry->d_name.len >= AFSNAMEMAX)
-		goto error;
-
 	key = afs_request_key(orig_dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		ret = PTR_ERR(key);

fs/autofs4/dev-ioctl.c

@@ -183,13 +183,14 @@ static int autofs_dev_ioctl_protosubver(struct file *fp,
 	return 0;
 }
 
+/* Find the topmost mount satisfying test() */
 static int find_autofs_mount(const char *pathname,
 			     struct path *res,
 			     int test(struct path *path, void *data),
 			     void *data)
 {
 	struct path path;
-	int err = kern_path(pathname, 0, &path);
+	int err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
 	if (err)
 		return err;
 	err = -ENOENT;
@@ -197,10 +198,9 @@ static int find_autofs_mount(const char *pathname,
 		if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
 			if (test(&path, data)) {
 				path_get(&path);
-				if (!err) /* already found some */
-					path_put(res);
 				*res = path;
 				err = 0;
+				break;
 			}
 		}
 		if (!follow_up(&path))
@@ -486,12 +486,11 @@ static int autofs_dev_ioctl_askumount(struct file *fp,
  * mount if there is one or 0 if it isn't a mountpoint.
  *
  * If we aren't supplied with a file descriptor then we
- * lookup the nameidata of the path and check if it is the
- * root of a mount. If a type is given we are looking for
- * a particular autofs mount and if we don't find a match
- * we return fail. If the located nameidata path is the
- * root of a mount we return 1 along with the super magic
- * of the mount or 0 otherwise.
+ * lookup the path and check if it is the root of a mount.
+ * If a type is given we are looking for a particular autofs
+ * mount and if we don't find a match we return fail. If the
+ * located path is the root of a mount we return 1 along with
+ * the super magic of the mount or 0 otherwise.
  *
  * In both cases the the device number (as returned by
  * new_encode_dev()) is also returned.
@@ -519,9 +518,11 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 
 	if (!fp || param->ioctlfd == -1) {
 		if (autofs_type_any(type))
-			err = kern_path(name, LOOKUP_FOLLOW, &path);
+			err = kern_path_mountpoint(AT_FDCWD,
+						   name, &path, LOOKUP_FOLLOW);
 		else
-			err = find_autofs_mount(name, &path, test_by_type, &type);
+			err = find_autofs_mount(name, &path,
+						test_by_type, &type);
 		if (err)
 			goto out;
 		devid = new_encode_dev(path.dentry->d_sb->s_dev);

fs/exportfs/expfs.c

@@ -231,7 +231,7 @@ static int filldir_one(void * __buf, const char * name, int len,
 	int result = 0;
 
 	buf->sequence++;
-	if (buf->ino == ino) {
+	if (buf->ino == ino && len <= NAME_MAX) {
 		memcpy(buf->name, name, len);
 		buf->name[len] = '\0';
 		buf->found = 1;

fs/internal.h

@@ -45,6 +45,9 @@ extern void __init chrdev_init(void);
  * namei.c
  */
 extern int __inode_permission(struct inode *, int);
+extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
+extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
+			   const char *, unsigned int, struct path *);
 
 /*
  * namespace.c

fs/namei.c

@@ -2209,7 +2209,7 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
 }
 
 /**
- * umount_lookup_last - look up last component for umount
+ * mountpoint_last - look up last component for umount
  * @nd:   pathwalk nameidata - currently pointing at parent directory of "last"
  * @path: pointer to container for result
  *
@@ -2236,25 +2236,28 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
  *         to the link, and nd->path will *not* be put.
  */
 static int
-umount_lookup_last(struct nameidata *nd, struct path *path)
+mountpoint_last(struct nameidata *nd, struct path *path)
 {
 	int error = 0;
 	struct dentry *dentry;
 	struct dentry *dir = nd->path.dentry;
 
-	if (unlikely(nd->flags & LOOKUP_RCU)) {
-		WARN_ON_ONCE(1);
-		error = -ECHILD;
-		goto error_check;
+	/* If we're in rcuwalk, drop out of it to handle last component */
+	if (nd->flags & LOOKUP_RCU) {
+		if (unlazy_walk(nd, NULL)) {
+			error = -ECHILD;
+			goto out;
+		}
 	}
 
 	nd->flags &= ~LOOKUP_PARENT;
 
 	if (unlikely(nd->last_type != LAST_NORM)) {
 		error = handle_dots(nd, nd->last_type);
-		if (!error)
-			dentry = dget(nd->path.dentry);
-		goto error_check;
+		if (error)
+			goto out;
+		dentry = dget(nd->path.dentry);
+		goto done;
 	}
 
 	mutex_lock(&dir->d_inode->i_mutex);
@@ -2268,44 +2271,43 @@ umount_lookup_last(struct nameidata *nd, struct path *path)
 		dentry = d_alloc(dir, &nd->last);
 		if (!dentry) {
 			error = -ENOMEM;
-		} else {
-			dentry = lookup_real(dir->d_inode, dentry, nd->flags);
-			if (IS_ERR(dentry))
-				error = PTR_ERR(dentry);
+			goto out;
 		}
+		dentry = lookup_real(dir->d_inode, dentry, nd->flags);
+		error = PTR_ERR(dentry);
+		if (IS_ERR(dentry))
+			goto out;
 	}
 	mutex_unlock(&dir->d_inode->i_mutex);
 
-error_check:
-	if (!error) {
-		if (!dentry->d_inode) {
-			error = -ENOENT;
-			dput(dentry);
-		} else {
-			path->dentry = dentry;
-			path->mnt = mntget(nd->path.mnt);
-			if (should_follow_link(dentry->d_inode,
-						nd->flags & LOOKUP_FOLLOW))
-				return 1;
-			follow_mount(path);
-		}
+done:
+	if (!dentry->d_inode) {
+		error = -ENOENT;
+		dput(dentry);
+		goto out;
 	}
+	path->dentry = dentry;
+	path->mnt = mntget(nd->path.mnt);
+	if (should_follow_link(dentry->d_inode, nd->flags & LOOKUP_FOLLOW))
+		return 1;
+	follow_mount(path);
+	error = 0;
+out:
 	terminate_walk(nd);
 	return error;
 }
 
 /**
- * path_umountat - look up a path to be umounted
+ * path_mountpoint - look up a path to be umounted
  * @dfd:	directory file descriptor to start walk from
  * @name:	full pathname to walk
  * @flags:	lookup flags
- * @nd:		pathwalk nameidata
  *
  * Look up the given name, but don't attempt to revalidate the last component.
  * Returns 0 and "path" will be valid on success; Retuns error otherwise.
  */
 static int
-path_umountat(int dfd, const char *name, struct path *path, unsigned int flags)
+path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags)
 {
 	struct file *base = NULL;
 	struct nameidata nd;
@@ -2320,16 +2322,7 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags)
 	if (err)
 		goto out;
 
-	/* If we're in rcuwalk, drop out of it to handle last component */
-	if (nd.flags & LOOKUP_RCU) {
-		err = unlazy_walk(&nd, NULL);
-		if (err) {
-			terminate_walk(&nd);
-			goto out;
-		}
-	}
-
-	err = umount_lookup_last(&nd, path);
+	err = mountpoint_last(&nd, path);
 	while (err > 0) {
 		void *cookie;
 		struct path link = *path;
@@ -2340,7 +2333,7 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags)
 		err = follow_link(&link, &nd, &cookie);
 		if (err)
 			break;
-		err = umount_lookup_last(&nd, path);
+		err = mountpoint_last(&nd, path);
 		put_link(&nd, &link, cookie);
 	}
 out:
@@ -2353,8 +2346,22 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags)
 	return err;
 }
 
+static int
+filename_mountpoint(int dfd, struct filename *s, struct path *path,
+			unsigned int flags)
+{
+	int error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_RCU);
+	if (unlikely(error == -ECHILD))
+		error = path_mountpoint(dfd, s->name, path, flags);
+	if (unlikely(error == -ESTALE))
+		error = path_mountpoint(dfd, s->name, path, flags | LOOKUP_REVAL);
+	if (likely(!error))
+		audit_inode(s, path->dentry, 0);
+	return error;
+}
+
 /**
- * user_path_umountat - lookup a path from userland in order to umount it
+ * user_path_mountpoint_at - lookup a path from userland in order to umount it
  * @dfd:	directory file descriptor
  * @name:	pathname from userland
  * @flags:	lookup flags
@@ -2368,28 +2375,27 @@ path_umountat(int dfd, const char *name, struct path *path, unsigned int flags)
  * Returns 0 and populates "path" on success.
  */
 int
-user_path_umountat(int dfd, const char __user *name, unsigned int flags,
+user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags,
 			struct path *path)
 {
 	struct filename *s = getname(name);
 	int error;
-
 	if (IS_ERR(s))
 		return PTR_ERR(s);
-
-	error = path_umountat(dfd, s->name, path, flags | LOOKUP_RCU);
-	if (unlikely(error == -ECHILD))
-		error = path_umountat(dfd, s->name, path, flags);
-	if (unlikely(error == -ESTALE))
-		error = path_umountat(dfd, s->name, path, flags | LOOKUP_REVAL);
-
-	if (likely(!error))
-		audit_inode(s, path->dentry, 0);
-
+	error = filename_mountpoint(dfd, s, path, flags);
 	putname(s);
 	return error;
 }
 
+int
+kern_path_mountpoint(int dfd, const char *name, struct path *path,
+			unsigned int flags)
+{
+	struct filename s = {.name = name};
+	return filename_mountpoint(dfd, &s, path, flags);
+}
+EXPORT_SYMBOL(kern_path_mountpoint);
+
 /*
  * It's inline, so penalty for filesystems that don't use sticky bit is
  * minimal.

fs/namespace.c

@@ -1321,7 +1321,7 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
 	if (!(flags & UMOUNT_NOFOLLOW))
 		lookup_flags |= LOOKUP_FOLLOW;
 
-	retval = user_path_umountat(AT_FDCWD, name, lookup_flags, &path);
+	retval = user_path_mountpoint_at(AT_FDCWD, name, lookup_flags, &path);
 	if (retval)
 		goto out;
 	mnt = real_mount(path.mnt);

fs/super.c

@@ -71,7 +71,7 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc)
 	if (!grab_super_passive(sb))
 		return -1;
 
-	if (sb->s_op && sb->s_op->nr_cached_objects)
+	if (sb->s_op->nr_cached_objects)
 		fs_objects = sb->s_op->nr_cached_objects(sb);
 
 	total_objects = sb->s_nr_dentry_unused +

include/linux/eventfd.h

@@ -9,7 +9,6 @@
 #define _LINUX_EVENTFD_H
 
 #include <linux/fcntl.h>
-#include <linux/file.h>
 #include <linux/wait.h>
 
 /*
@@ -26,6 +25,8 @@
 #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
 #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
 
+struct file;
+
 #ifdef CONFIG_EVENTFD
 
 struct file *eventfd_file_create(unsigned int count, int flags);

include/linux/namei.h

@@ -58,7 +58,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
 
 extern int user_path_at(int, const char __user *, unsigned, struct path *);
 extern int user_path_at_empty(int, const char __user *, unsigned, struct path *, int *empty);
-extern int user_path_umountat(int, const char __user *, unsigned int, struct path *);
 
 #define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
 #define user_lpath(name, path) user_path_at(AT_FDCWD, name, 0, path)
@@ -71,8 +70,7 @@ extern struct dentry *kern_path_create(int, const char *, struct path *, unsigne
 extern struct dentry *user_path_create(int, const char __user *, struct path *, unsigned int);
 extern void done_path_create(struct path *, struct dentry *);
 extern struct dentry *kern_path_locked(const char *, struct path *);
-extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
-			   const char *, unsigned int, struct path *);
+extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int);
 
 extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
 

kernel/cgroup.c

@@ -60,6 +60,7 @@
 #include <linux/poll.h>
 #include <linux/flex_array.h> /* used in cgroup_attach_task */
 #include <linux/kthread.h>
+#include <linux/file.h>
 
 #include <linux/atomic.h>
 
@@ -4034,8 +4035,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
 	struct cgroup_event *event;
 	struct cgroup_subsys_state *cfile_css;
 	unsigned int efd, cfd;
-	struct file *efile;
-	struct file *cfile;
+	struct fd efile;
+	struct fd cfile;
 	char *endp;
 	int ret;
 
@@ -4058,31 +4059,31 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
 	init_waitqueue_func_entry(&event->wait, cgroup_event_wake);
 	INIT_WORK(&event->remove, cgroup_event_remove);
 
-	efile = eventfd_fget(efd);
-	if (IS_ERR(efile)) {
-		ret = PTR_ERR(efile);
+	efile = fdget(efd);
+	if (!efile.file) {
+		ret = -EBADF;
 		goto out_kfree;
 	}
 
-	event->eventfd = eventfd_ctx_fileget(efile);
+	event->eventfd = eventfd_ctx_fileget(efile.file);
 	if (IS_ERR(event->eventfd)) {
 		ret = PTR_ERR(event->eventfd);
 		goto out_put_efile;
 	}
 
-	cfile = fget(cfd);
-	if (!cfile) {
+	cfile = fdget(cfd);
+	if (!cfile.file) {
 		ret = -EBADF;
 		goto out_put_eventfd;
 	}
 
 	/* the process need read permission on control file */
 	/* AV: shouldn't we check that it's been opened for read instead? */
-	ret = inode_permission(file_inode(cfile), MAY_READ);
+	ret = inode_permission(file_inode(cfile.file), MAY_READ);
 	if (ret < 0)
 		goto out_put_cfile;
 
-	event->cft = __file_cft(cfile);
+	event->cft = __file_cft(cfile.file);
 	if (IS_ERR(event->cft)) {
 		ret = PTR_ERR(event->cft);
 		goto out_put_cfile;
@@ -4103,7 +4104,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
 
 	ret = -EINVAL;
 	event->css = cgroup_css(cgrp, event->cft->ss);
-	cfile_css = css_from_dir(cfile->f_dentry->d_parent, event->cft->ss);
+	cfile_css = css_from_dir(cfile.file->f_dentry->d_parent, event->cft->ss);
 	if (event->css && event->css == cfile_css && css_tryget(event->css))
 		ret = 0;
 
@@ -4121,25 +4122,25 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
 	if (ret)
 		goto out_put_css;
 
-	efile->f_op->poll(efile, &event->pt);
+	efile.file->f_op->poll(efile.file, &event->pt);
 
 	spin_lock(&cgrp->event_list_lock);
 	list_add(&event->list, &cgrp->event_list);
 	spin_unlock(&cgrp->event_list_lock);
 
-	fput(cfile);
-	fput(efile);
+	fdput(cfile);
+	fdput(efile);
 
 	return 0;
 
 out_put_css:
 	css_put(event->css);
 out_put_cfile:
-	fput(cfile);
+	fdput(cfile);
 out_put_eventfd:
 	eventfd_ctx_put(event->eventfd);
 out_put_efile:
-	fput(efile);
+	fdput(efile);
 out_kfree:
 	kfree(event);