Unexport do_add_mount() and add in follow_automount(), not ->d_automount()

Unexport do_add_mount() and make ->d_automount() return the vfsmount to be added rather than calling do_add_mount() itself. follow_automount() will then do the addition. This slightly complicates things as ->d_automount() normally wants to add the new vfsmount to an expiration list and start an expiration timer. The problem with that is that the vfsmount will be deleted if it has a refcount of 1 and the timer will not repeat if the expiration list is empty. To this end, we require the vfsmount to be returned from d_automount() with a refcount of (at least) 2. One of these refs will be dropped unconditionally. In addition, follow_automount() must get a 3rd ref around the call to do_add_mount() lest it eat a ref and return an error, leaving the mount we have open to being expired as we would otherwise have only 1 ref on it. d_automount() should also add the the vfsmount to the expiration list (by calling mnt_set_expiry()) and start the expiration timer before returning, if this mechanism is to be used. The vfsmount will be unlinked from the expiration list by follow_automount() if do_add_mount() fails. This patch also fixes the call to do_add_mount() for AFS to propagate the mount flags from the parent vfsmount. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Unexport do_add_mount() and add in follow_automount(), not ->d_automount()
Unexport do_add_mount() and make ->d_automount() return the vfsmount to be added rather than calling do_add_mount() itself. follow_automount() will then do the addition. This slightly complicates things as ->d_automount() normally wants to add the new vfsmount to an expiration list and start an expiration timer. The problem with that is that the vfsmount will be deleted if it has a refcount of 1 and the timer will not repeat if the expiration list is empty. To this end, we require the vfsmount to be returned from d_automount() with a refcount of (at least) 2. One of these refs will be dropped unconditionally. In addition, follow_automount() must get a 3rd ref around the call to do_add_mount() lest it eat a ref and return an error, leaving the mount we have open to being expired as we would otherwise have only 1 ref on it. d_automount() should also add the the vfsmount to the expiration list (by calling mnt_set_expiry()) and start the expiration timer before returning, if this mechanism is to be used. The vfsmount will be unlinked from the expiration list by follow_automount() if do_add_mount() fails. This patch also fixes the call to do_add_mount() for AFS to propagate the mount flags from the parent vfsmount. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
David Howells · Al Viro
1 parent ab90911ff9
Showing 8 changed files with 101 additions and 89 deletions Side-by-side Diff
Documentation/filesystems/vfs.txt
fs/afs/mntpt.c
fs/cifs/cifs_dfs_ref.c
fs/internal.h
fs/namei.c
fs/namespace.c
fs/nfs/namespace.c
include/linux/mount.h
@@ -933,15 +933,20 @@
 	dynamic_dname() helper function is provided to take care of this.
  
   d_automount: called when an automount dentry is to be traversed (optional).
-	This should create a new VFS mount record, mount it on the directory
-	and return the record to the caller.  The caller is supplied with a
-	path parameter giving the automount directory to describe the automount
-	target and the parent VFS mount record to provide inheritable mount
-	parameters.  NULL should be returned if someone else managed to make
-	the automount first.  If the automount failed, then an error code
-	should be returned.  If -EISDIR is returned, then the directory will
-	be treated as an ordinary directory and returned to pathwalk to
-	continue walking.
+	This should create a new VFS mount record and return the record to the
+	caller.  The caller is supplied with a path parameter giving the
+	automount directory to describe the automount target and the parent
+	VFS mount record to provide inheritable mount parameters.  NULL should
+	be returned if someone else managed to make the automount first.  If
+	the vfsmount creation failed, then an error code should be returned.
+	If -EISDIR is returned, then the directory will be treated as an
+	ordinary directory and returned to pathwalk to continue walking.
+
+	If a vfsmount is returned, the caller will attempt to mount it on the
+	mountpoint and will remove the vfsmount from its expiration list in
+	the case of failure.  The vfsmount should be returned with 2 refs on
+	it to prevent automatic expiration - the caller will clean up the
+	additional ref.
  
 	This function is only used if DCACHE_NEED_AUTOMOUNT is set on the
 	dentry.  This is set by __d_instantiate() if S_AUTOMOUNT is set on the
@@ -241,7 +241,6 @@
 struct vfsmount *afs_d_automount(struct path *path)
 {
 	struct vfsmount *newmnt;
-	int err;
  
 	_enter("{%s,%s}", path->mnt->mnt_devname, path->dentry->d_name.name);
  
@@ -249,24 +248,12 @@
 	if (IS_ERR(newmnt))
 		return newmnt;
  
-	mntget(newmnt);
-	err = do_add_mount(newmnt, path, MNT_SHRINKABLE, &afs_vfsmounts);
-	switch (err) {
-	case 0:
-		queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
-				   afs_mntpt_expiry_timeout * HZ);
-		_leave(" = %p {%s}", newmnt, newmnt->mnt_devname);
-		return newmnt;
-	case -EBUSY:
-		/* someone else made a mount here whilst we were busy */
-		mntput(newmnt);
-		_leave(" = NULL [EBUSY]");
-		return NULL;
-	default:
-		mntput(newmnt);
-		_leave(" = %d", err);
-		return ERR_PTR(err);
-	}
+	mntget(newmnt); /* prevent immediate expiration */
+	mnt_set_expiry(newmnt, &afs_vfsmounts);
+	queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
+			   afs_mntpt_expiry_timeout * HZ);
+	_leave(" = %p {%s}", newmnt, newmnt->mnt_devname);
+	return newmnt;
 }
  
 /*
@@ -351,7 +351,6 @@
 struct vfsmount *cifs_dfs_d_automount(struct path *path)
 {
 	struct vfsmount *newmnt;
-	int err;
  
 	cFYI(1, "in %s", __func__);
  
@@ -361,25 +360,12 @@
 		return newmnt;
 	}
  
-	mntget(newmnt);
-	err = do_add_mount(newmnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE,
-			   &cifs_dfs_automount_list);
-	switch (err) {
-	case 0:
-		schedule_delayed_work(&cifs_dfs_automount_task,
-				      cifs_dfs_mountpoint_expiry_timeout);
-		cFYI(1, "leaving %s [ok]" , __func__);
-		return newmnt;
-	case -EBUSY:
-		/* someone else made a mount here whilst we were busy */
-		mntput(newmnt);
-		cFYI(1, "leaving %s [EBUSY]" , __func__);
-		return NULL;
-	default:
-		mntput(newmnt);
-		cFYI(1, "leaving %s [error %d]" , __func__, err);
-		return ERR_PTR(err);
-	}
+	mntget(newmnt); /* prevent immediate expiration */
+	mnt_set_expiry(newmnt, &cifs_dfs_automount_list);
+	schedule_delayed_work(&cifs_dfs_automount_task,
+			      cifs_dfs_mountpoint_expiry_timeout);
+	cFYI(1, "leaving %s [ok]" , __func__);
+	return newmnt;
 }
  
 const struct inode_operations cifs_dfs_referral_inode_operations = {
@@ -70,6 +70,8 @@
 extern void release_mounts(struct list_head *);
 extern void umount_tree(struct vfsmount *, int, struct list_head *);
 extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int);
+extern int do_add_mount(struct vfsmount *, struct path *, int);
+extern void mnt_clear_expiry(struct vfsmount *);
  
 extern void __init mnt_init(void);
  
@@ -900,6 +900,7 @@
 			    bool *need_mntput)
 {
 	struct vfsmount *mnt;
+	int err;
  
 	if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
 		return -EREMOTE;
  
  
  
  
@@ -942,22 +943,49 @@
 			return -EREMOTE;
 		return PTR_ERR(mnt);
 	}
+
 	if (!mnt) /* mount collision */
 		return 0;
  
+	/* The new mount record should have at least 2 refs to prevent it being
+	 * expired before we get a chance to add it
+	 */
+	BUG_ON(mnt_get_count(mnt) < 2);
+
 	if (mnt->mnt_sb == path->mnt->mnt_sb &&
 	    mnt->mnt_root == path->dentry) {
+		mnt_clear_expiry(mnt);
 		mntput(mnt);
+		mntput(mnt);
 		return -ELOOP;
 	}
  
-	dput(path->dentry);
-	if (*need_mntput)
-		mntput(path->mnt);
-	path->mnt = mnt;
-	path->dentry = dget(mnt->mnt_root);
-	*need_mntput = true;
-	return 0;
+	/* We need to add the mountpoint to the parent.  The filesystem may
+	 * have placed it on an expiry list, and so we need to make sure it
+	 * won't be expired under us if do_add_mount() fails (do_add_mount()
+	 * will eat a reference unconditionally).
+	 */
+	mntget(mnt);
+	err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+	switch (err) {
+	case -EBUSY:
+		/* Someone else made a mount here whilst we were busy */
+		err = 0;
+	default:
+		mnt_clear_expiry(mnt);
+		mntput(mnt);
+		mntput(mnt);
+		return err;
+	case 0:
+		mntput(mnt);
+		dput(path->dentry);
+		if (*need_mntput)
+			mntput(path->mnt);
+		path->mnt = mnt;
+		path->dentry = dget(mnt->mnt_root);
+		*need_mntput = true;
+		return 0;
+	}
 }
  
 /*
@@ -1925,15 +1925,14 @@
 	if (IS_ERR(mnt))
 		return PTR_ERR(mnt);
  
-	return do_add_mount(mnt, path, mnt_flags, NULL);
+	return do_add_mount(mnt, path, mnt_flags);
 }
  
 /*
  * add a mount into a namespace's mount tree
- * - provide the option of adding the new mount to an expiration list
+ * - this unconditionally eats one of the caller's references to newmnt.
  */
-int do_add_mount(struct vfsmount *newmnt, struct path *path,
-		 int mnt_flags, struct list_head *fslist)
+int do_add_mount(struct vfsmount *newmnt, struct path *path, int mnt_flags)
 {
 	int err;
  
@@ -1963,9 +1962,6 @@
 	if ((err = graft_tree(newmnt, path)))
 		goto unlock;
  
-	if (fslist) /* add to the specified expiration list */
-		list_add_tail(&newmnt->mnt_expire, fslist);
-
 	up_write(&namespace_sem);
 	return 0;
  
@@ -1975,7 +1971,36 @@
 	return err;
 }
  
-EXPORT_SYMBOL_GPL(do_add_mount);
+/**
+ * mnt_set_expiry - Put a mount on an expiration list
+ * @mnt: The mount to list.
+ * @expiry_list: The list to add the mount to.
+ */
+void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list)
+{
+	down_write(&namespace_sem);
+	br_write_lock(vfsmount_lock);
+
+	list_add_tail(&mnt->mnt_expire, expiry_list);
+
+	br_write_unlock(vfsmount_lock);
+	up_write(&namespace_sem);
+}
+EXPORT_SYMBOL(mnt_set_expiry);
+
+/*
+ * Remove a vfsmount from any expiration list it may be on
+ */
+void mnt_clear_expiry(struct vfsmount *mnt)
+{
+	if (!list_empty(&mnt->mnt_expire)) {
+		down_write(&namespace_sem);
+		br_write_lock(vfsmount_lock);
+		list_del_init(&mnt->mnt_expire);
+		br_write_unlock(vfsmount_lock);
+		up_write(&namespace_sem);
+	}
+}
  
 /*
  * process a list of expirable mountpoints with the intent of discarding any
@@ -149,26 +149,10 @@
 	if (IS_ERR(mnt))
 		goto out;
  
-	mntget(mnt);
-	err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE,
-			   &nfs_automount_list);
-	switch (err) {
-	case 0:
-		dprintk("%s: done, success\n", __func__);
-		schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
-		break;
-	case -EBUSY:
-		/* someone else made a mount here whilst we were busy */
-		mntput(mnt);
-		dprintk("%s: done, collision\n", __func__);
-		mnt = NULL;
-		break;
-	default:
-		mntput(mnt);
-		dprintk("%s: done, error %d\n", __func__, err);
-		mnt = ERR_PTR(err);
-		break;
-	}
+	dprintk("%s: done, success\n", __func__);
+	mntget(mnt); /* prevent immediate expiration */
+	mnt_set_expiry(mnt, &nfs_automount_list);
+	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
  
 out:
 	nfs_free_fattr(fattr);
@@ -110,12 +110,7 @@
 				      int flags, const char *name,
 				      void *data);
  
-struct nameidata;
-
-struct path;
-extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
-			int mnt_flags, struct list_head *fslist);
-
+extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
 extern void mark_mounts_for_expiry(struct list_head *mounts);
  
 extern dev_t name_to_dev_t(char *name);
...	...	@@ -933,15 +933,20 @@
933	933	dynamic_dname() helper function is provided to take care of this.
934	934
935	935	d_automount: called when an automount dentry is to be traversed (optional).
936		- This should create a new VFS mount record, mount it on the directory
937		- and return the record to the caller. The caller is supplied with a
938		- path parameter giving the automount directory to describe the automount
939		- target and the parent VFS mount record to provide inheritable mount
940		- parameters. NULL should be returned if someone else managed to make
941		- the automount first. If the automount failed, then an error code
942		- should be returned. If -EISDIR is returned, then the directory will
943		- be treated as an ordinary directory and returned to pathwalk to
944		- continue walking.
	936	+ This should create a new VFS mount record and return the record to the
	937	+ caller. The caller is supplied with a path parameter giving the
	938	+ automount directory to describe the automount target and the parent
	939	+ VFS mount record to provide inheritable mount parameters. NULL should
	940	+ be returned if someone else managed to make the automount first. If
	941	+ the vfsmount creation failed, then an error code should be returned.
	942	+ If -EISDIR is returned, then the directory will be treated as an
	943	+ ordinary directory and returned to pathwalk to continue walking.
	944	+
	945	+ If a vfsmount is returned, the caller will attempt to mount it on the
	946	+ mountpoint and will remove the vfsmount from its expiration list in
	947	+ the case of failure. The vfsmount should be returned with 2 refs on
	948	+ it to prevent automatic expiration - the caller will clean up the
	949	+ additional ref.
945	950
946	951	This function is only used if DCACHE_NEED_AUTOMOUNT is set on the
947	952	dentry. This is set by __d_instantiate() if S_AUTOMOUNT is set on the
...	...	@@ -241,7 +241,6 @@
241	241	struct vfsmount afs_d_automount(struct path path)
242	242	{
243	243	struct vfsmount *newmnt;
244		- int err;
245	244
246	245	_enter("{%s,%s}", path->mnt->mnt_devname, path->dentry->d_name.name);
247	246
...	...	@@ -249,24 +248,12 @@
249	248	if (IS_ERR(newmnt))
250	249	return newmnt;
251	250
252		- mntget(newmnt);
253		- err = do_add_mount(newmnt, path, MNT_SHRINKABLE, &afs_vfsmounts);
254		- switch (err) {
255		- case 0:
256		- queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
257		- afs_mntpt_expiry_timeout * HZ);
258		- _leave(" = %p {%s}", newmnt, newmnt->mnt_devname);
259		- return newmnt;
260		- case -EBUSY:
261		- /* someone else made a mount here whilst we were busy */
262		- mntput(newmnt);
263		- _leave(" = NULL [EBUSY]");
264		- return NULL;
265		- default:
266		- mntput(newmnt);
267		- _leave(" = %d", err);
268		- return ERR_PTR(err);
269		- }
	251	+ mntget(newmnt); /* prevent immediate expiration */
	252	+ mnt_set_expiry(newmnt, &afs_vfsmounts);
	253	+ queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
	254	+ afs_mntpt_expiry_timeout * HZ);
	255	+ _leave(" = %p {%s}", newmnt, newmnt->mnt_devname);
	256	+ return newmnt;
270	257	}
271	258
272	259	/*
...	...	@@ -351,7 +351,6 @@
351	351	struct vfsmount cifs_dfs_d_automount(struct path path)
352	352	{
353	353	struct vfsmount *newmnt;
354		- int err;
355	354
356	355	cFYI(1, "in %s", __func__);
357	356
...	...	@@ -361,25 +360,12 @@
361	360	return newmnt;
362	361	}
363	362
364		- mntget(newmnt);
365		- err = do_add_mount(newmnt, path, path->mnt->mnt_flags \| MNT_SHRINKABLE,
366		- &cifs_dfs_automount_list);
367		- switch (err) {
368		- case 0:
369		- schedule_delayed_work(&cifs_dfs_automount_task,
370		- cifs_dfs_mountpoint_expiry_timeout);
371		- cFYI(1, "leaving %s [ok]" , __func__);
372		- return newmnt;
373		- case -EBUSY:
374		- /* someone else made a mount here whilst we were busy */
375		- mntput(newmnt);
376		- cFYI(1, "leaving %s [EBUSY]" , __func__);
377		- return NULL;
378		- default:
379		- mntput(newmnt);
380		- cFYI(1, "leaving %s [error %d]" , __func__, err);
381		- return ERR_PTR(err);
382		- }
	363	+ mntget(newmnt); /* prevent immediate expiration */
	364	+ mnt_set_expiry(newmnt, &cifs_dfs_automount_list);
	365	+ schedule_delayed_work(&cifs_dfs_automount_task,
	366	+ cifs_dfs_mountpoint_expiry_timeout);
	367	+ cFYI(1, "leaving %s [ok]" , __func__);
	368	+ return newmnt;
383	369	}
384	370
385	371	const struct inode_operations cifs_dfs_referral_inode_operations = {
...	...	@@ -70,6 +70,8 @@
70	70	extern void release_mounts(struct list_head *);
71	71	extern void umount_tree(struct vfsmount , int, struct list_head );
72	72	extern struct vfsmount copy_tree(struct vfsmount , struct dentry *, int);
	73	+extern int do_add_mount(struct vfsmount , struct path , int);
	74	+extern void mnt_clear_expiry(struct vfsmount *);
73	75
74	76	extern void __init mnt_init(void);
75	77
...	...	@@ -900,6 +900,7 @@
900	900	bool *need_mntput)
901	901	{
902	902	struct vfsmount *mnt;
	903	+ int err;
903	904
904	905	if (!path->dentry->d_op \|\| !path->dentry->d_op->d_automount)
905	906	return -EREMOTE;
906	907
907	908
908	909
909	910
...	...	@@ -942,22 +943,49 @@
942	943	return -EREMOTE;
943	944	return PTR_ERR(mnt);
944	945	}
	946	+
945	947	if (!mnt) /* mount collision */
946	948	return 0;
947	949
	950	+ /* The new mount record should have at least 2 refs to prevent it being
	951	+ * expired before we get a chance to add it
	952	+ */
	953	+ BUG_ON(mnt_get_count(mnt) < 2);
	954	+
948	955	if (mnt->mnt_sb == path->mnt->mnt_sb &&
949	956	mnt->mnt_root == path->dentry) {
	957	+ mnt_clear_expiry(mnt);
950	958	mntput(mnt);
	959	+ mntput(mnt);
951	960	return -ELOOP;
952	961	}
953	962
954		- dput(path->dentry);
955		- if (*need_mntput)
956		- mntput(path->mnt);
957		- path->mnt = mnt;
958		- path->dentry = dget(mnt->mnt_root);
959		- *need_mntput = true;
960		- return 0;
	963	+ /* We need to add the mountpoint to the parent. The filesystem may
	964	+ * have placed it on an expiry list, and so we need to make sure it
	965	+ * won't be expired under us if do_add_mount() fails (do_add_mount()
	966	+ * will eat a reference unconditionally).
	967	+ */
	968	+ mntget(mnt);
	969	+ err = do_add_mount(mnt, path, path->mnt->mnt_flags \| MNT_SHRINKABLE);
	970	+ switch (err) {
	971	+ case -EBUSY:
	972	+ /* Someone else made a mount here whilst we were busy */
	973	+ err = 0;
	974	+ default:
	975	+ mnt_clear_expiry(mnt);
	976	+ mntput(mnt);
	977	+ mntput(mnt);
	978	+ return err;
	979	+ case 0:
	980	+ mntput(mnt);
	981	+ dput(path->dentry);
	982	+ if (*need_mntput)
	983	+ mntput(path->mnt);
	984	+ path->mnt = mnt;
	985	+ path->dentry = dget(mnt->mnt_root);
	986	+ *need_mntput = true;
	987	+ return 0;
	988	+ }
961	989	}
962	990
963	991	/*
...	...	@@ -1925,15 +1925,14 @@
1925	1925	if (IS_ERR(mnt))
1926	1926	return PTR_ERR(mnt);
1927	1927
1928		- return do_add_mount(mnt, path, mnt_flags, NULL);
	1928	+ return do_add_mount(mnt, path, mnt_flags);
1929	1929	}
1930	1930
1931	1931	/*
1932	1932	* add a mount into a namespace's mount tree
1933		- * - provide the option of adding the new mount to an expiration list
	1933	+ * - this unconditionally eats one of the caller's references to newmnt.
1934	1934	*/
1935		-int do_add_mount(struct vfsmount newmnt, struct path path,
1936		- int mnt_flags, struct list_head *fslist)
	1935	+int do_add_mount(struct vfsmount newmnt, struct path path, int mnt_flags)
1937	1936	{
1938	1937	int err;
1939	1938
...	...	@@ -1963,9 +1962,6 @@
1963	1962	if ((err = graft_tree(newmnt, path)))
1964	1963	goto unlock;
1965	1964
1966		- if (fslist) /* add to the specified expiration list */
1967		- list_add_tail(&newmnt->mnt_expire, fslist);
1968		-
1969	1965	up_write(&namespace_sem);
1970	1966	return 0;
1971	1967
...	...	@@ -1975,7 +1971,36 @@
1975	1971	return err;
1976	1972	}
1977	1973
1978		-EXPORT_SYMBOL_GPL(do_add_mount);
	1974	+/**
	1975	+ * mnt_set_expiry - Put a mount on an expiration list
	1976	+ * @mnt: The mount to list.
	1977	+ * @expiry_list: The list to add the mount to.
	1978	+ */
	1979	+void mnt_set_expiry(struct vfsmount mnt, struct list_head expiry_list)
	1980	+{
	1981	+ down_write(&namespace_sem);
	1982	+ br_write_lock(vfsmount_lock);
	1983	+
	1984	+ list_add_tail(&mnt->mnt_expire, expiry_list);
	1985	+
	1986	+ br_write_unlock(vfsmount_lock);
	1987	+ up_write(&namespace_sem);
	1988	+}
	1989	+EXPORT_SYMBOL(mnt_set_expiry);
	1990	+
	1991	+/*
	1992	+ * Remove a vfsmount from any expiration list it may be on
	1993	+ */
	1994	+void mnt_clear_expiry(struct vfsmount *mnt)
	1995	+{
	1996	+ if (!list_empty(&mnt->mnt_expire)) {
	1997	+ down_write(&namespace_sem);
	1998	+ br_write_lock(vfsmount_lock);
	1999	+ list_del_init(&mnt->mnt_expire);
	2000	+ br_write_unlock(vfsmount_lock);
	2001	+ up_write(&namespace_sem);
	2002	+ }
	2003	+}
1979	2004
1980	2005	/*
1981	2006	* process a list of expirable mountpoints with the intent of discarding any
...	...	@@ -149,26 +149,10 @@
149	149	if (IS_ERR(mnt))
150	150	goto out;
151	151
152		- mntget(mnt);
153		- err = do_add_mount(mnt, path, path->mnt->mnt_flags \| MNT_SHRINKABLE,
154		- &nfs_automount_list);
155		- switch (err) {
156		- case 0:
157		- dprintk("%s: done, success\n", __func__);
158		- schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
159		- break;
160		- case -EBUSY:
161		- /* someone else made a mount here whilst we were busy */
162		- mntput(mnt);
163		- dprintk("%s: done, collision\n", __func__);
164		- mnt = NULL;
165		- break;
166		- default:
167		- mntput(mnt);
168		- dprintk("%s: done, error %d\n", __func__, err);
169		- mnt = ERR_PTR(err);
170		- break;
171		- }
	152	+ dprintk("%s: done, success\n", __func__);
	153	+ mntget(mnt); /* prevent immediate expiration */
	154	+ mnt_set_expiry(mnt, &nfs_automount_list);
	155	+ schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
172	156
173	157	out:
174	158	nfs_free_fattr(fattr);
...	...	@@ -110,12 +110,7 @@
110	110	int flags, const char *name,
111	111	void *data);
112	112
113		-struct nameidata;
114		-
115		-struct path;
116		-extern int do_add_mount(struct vfsmount newmnt, struct path path,
117		- int mnt_flags, struct list_head *fslist);
118		-
	113	+extern void mnt_set_expiry(struct vfsmount mnt, struct list_head expiry_list);
119	114	extern void mark_mounts_for_expiry(struct list_head *mounts);
120	115
121	116	extern dev_t name_to_dev_t(char *name);