NFS: Use d_automount() rather than abusing follow_link()

Make NFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

NFS: Use d_automount() rather than abusing follow_link()
Make NFS use the new d_automount() dentry operation rather than abusing follow_link() on directories. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Ian Kent <raven@themaw.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
David Howells · Al Viro
1 parent d18610b0ce
Showing 5 changed files with 46 additions and 48 deletions Side-by-side Diff
fs/nfs/dir.c
fs/nfs/inode.c
fs/nfs/internal.h
fs/nfs/namespace.c
include/linux/nfs_fs.h
@@ -970,7 +970,7 @@
 {
 	struct nfs_server *server = NFS_SERVER(inode);
  
-	if (test_bit(NFS_INO_MOUNTPOINT, &NFS_I(inode)->flags))
+	if (IS_AUTOMOUNT(inode))
 		return 0;
 	if (nd != NULL) {
 		/* VFS wants an on-the-wire revalidation */
@@ -1173,6 +1173,7 @@
 	.d_revalidate	= nfs_lookup_revalidate,
 	.d_delete	= nfs_dentry_delete,
 	.d_iput		= nfs_dentry_iput,
+	.d_automount	= nfs_d_automount,
 };
  
 static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
@@ -1246,6 +1247,7 @@
 	.d_revalidate	= nfs_open_revalidate,
 	.d_delete	= nfs_dentry_delete,
 	.d_iput		= nfs_dentry_iput,
+	.d_automount	= nfs_d_automount,
 };
  
 /*
@@ -300,7 +300,7 @@
 				else
 					inode->i_op = &nfs_mountpoint_inode_operations;
 				inode->i_fop = NULL;
-				set_bit(NFS_INO_MOUNTPOINT, &nfsi->flags);
+				inode->i_flags |= S_AUTOMOUNT;
 			}
 		} else if (S_ISLNK(inode->i_mode))
 			inode->i_op = &nfs_symlink_inode_operations;
@@ -1208,7 +1208,7 @@
 	/* Update the fsid? */
 	if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&
 			!nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
-			!test_bit(NFS_INO_MOUNTPOINT, &nfsi->flags))
+			!IS_AUTOMOUNT(inode))
 		server->fsid = fattr->fsid;
  
 	/*
@@ -252,6 +252,7 @@
 		      const struct dentry *droot,
 		      const struct dentry *dentry,
 		      char *buffer, ssize_t buflen);
+extern struct vfsmount *nfs_d_automount(struct path *path);
  
 /* getroot.c */
 extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *);
@@ -97,9 +97,8 @@
 }
  
 /*
- * nfs_follow_mountpoint - handle crossing a mountpoint on the server
- * @dentry - dentry of mountpoint
- * @nd - nameidata info
+ * nfs_d_automount - Handle crossing a mountpoint on the server
+ * @path - The mountpoint
  *
  * When we encounter a mountpoint on the server, we want to set up
  * a mountpoint on the client too, to prevent inode numbers from
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
@@ -109,84 +108,81 @@
  * situation, and that different filesystems may want to use
  * different security flavours.
  */
-static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
+struct vfsmount *nfs_d_automount(struct path *path)
 {
 	struct vfsmount *mnt;
-	struct nfs_server *server = NFS_SERVER(dentry->d_inode);
+	struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
 	struct dentry *parent;
 	struct nfs_fh *fh = NULL;
 	struct nfs_fattr *fattr = NULL;
 	int err;
  
-	dprintk("--> nfs_follow_mountpoint()\n");
+	dprintk("--> nfs_d_automount()\n");
  
-	err = -ESTALE;
-	if (IS_ROOT(dentry))
-		goto out_err;
+	mnt = ERR_PTR(-ESTALE);
+	if (IS_ROOT(path->dentry))
+		goto out_nofree;
  
-	err = -ENOMEM;
+	mnt = ERR_PTR(-ENOMEM);
 	fh = nfs_alloc_fhandle();
 	fattr = nfs_alloc_fattr();
 	if (fh == NULL || fattr == NULL)
-		goto out_err;
+		goto out;
  
 	dprintk("%s: enter\n", __func__);
-	dput(nd->path.dentry);
-	nd->path.dentry = dget(dentry);
  
-	/* Look it up again */
-	parent = dget_parent(nd->path.dentry);
+	/* Look it up again to get its attributes */
+	parent = dget_parent(path->dentry);
 	err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
-						  &nd->path.dentry->d_name,
+						  &path->dentry->d_name,
 						  fh, fattr);
 	dput(parent);
-	if (err != 0)
-		goto out_err;
+	if (err != 0) {
+		mnt = ERR_PTR(err);
+		goto out;
+	}
  
 	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
-		mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry);
+		mnt = nfs_do_refmount(path->mnt, path->dentry);
 	else
-		mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh,
-				      fattr);
-	err = PTR_ERR(mnt);
+		mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);
 	if (IS_ERR(mnt))
-		goto out_err;
+		goto out;
  
 	mntget(mnt);
-	err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE,
+	err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE,
 			   &nfs_automount_list);
-	if (err < 0) {
+	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);
-		if (err == -EBUSY)
-			goto out_follow;
-		goto out_err;
+		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;
 	}
-	path_put(&nd->path);
-	nd->path.mnt = mnt;
-	nd->path.dentry = dget(mnt->mnt_root);
-	schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
+
 out:
 	nfs_free_fattr(fattr);
 	nfs_free_fhandle(fh);
-	dprintk("%s: done, returned %d\n", __func__, err);
-
-	dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
-	return ERR_PTR(err);
-out_err:
-	path_put(&nd->path);
-	goto out;
-out_follow:
-	err = follow_down(&nd->path, false);
-	goto out;
+out_nofree:
+	dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt);
+	return mnt;
 }
  
 const struct inode_operations nfs_mountpoint_inode_operations = {
-	.follow_link	= nfs_follow_mountpoint,
 	.getattr	= nfs_getattr,
 };
  
 const struct inode_operations nfs_referral_inode_operations = {
-	.follow_link	= nfs_follow_mountpoint,
 };
  
 static void nfs_expire_automounts(struct work_struct *work)
@@ -215,7 +215,6 @@
 #define NFS_INO_ADVISE_RDPLUS	(0)		/* advise readdirplus */
 #define NFS_INO_STALE		(1)		/* possible stale inode */
 #define NFS_INO_ACL_LRU_SET	(2)		/* Inode is on the LRU list */
-#define NFS_INO_MOUNTPOINT	(3)		/* inode is remote mountpoint */
 #define NFS_INO_FLUSHING	(4)		/* inode is flushing out data */
 #define NFS_INO_FSCACHE		(5)		/* inode can be cached by FS-Cache */
 #define NFS_INO_FSCACHE_LOCK	(6)		/* FS-Cache cookie management lock */
...	...	@@ -970,7 +970,7 @@
970	970	{
971	971	struct nfs_server *server = NFS_SERVER(inode);
972	972
973		- if (test_bit(NFS_INO_MOUNTPOINT, &NFS_I(inode)->flags))
	973	+ if (IS_AUTOMOUNT(inode))
974	974	return 0;
975	975	if (nd != NULL) {
976	976	/* VFS wants an on-the-wire revalidation */
...	...	@@ -1173,6 +1173,7 @@
1173	1173	.d_revalidate = nfs_lookup_revalidate,
1174	1174	.d_delete = nfs_dentry_delete,
1175	1175	.d_iput = nfs_dentry_iput,
	1176	+ .d_automount = nfs_d_automount,
1176	1177	};
1177	1178
1178	1179	static struct dentry nfs_lookup(struct inode dir, struct dentry * dentry, struct nameidata *nd)
...	...	@@ -1246,6 +1247,7 @@
1246	1247	.d_revalidate = nfs_open_revalidate,
1247	1248	.d_delete = nfs_dentry_delete,
1248	1249	.d_iput = nfs_dentry_iput,
	1250	+ .d_automount = nfs_d_automount,
1249	1251	};
1250	1252
1251	1253	/*
...	...	@@ -300,7 +300,7 @@
300	300	else
301	301	inode->i_op = &nfs_mountpoint_inode_operations;
302	302	inode->i_fop = NULL;
303		- set_bit(NFS_INO_MOUNTPOINT, &nfsi->flags);
	303	+ inode->i_flags \|= S_AUTOMOUNT;
304	304	}
305	305	} else if (S_ISLNK(inode->i_mode))
306	306	inode->i_op = &nfs_symlink_inode_operations;
...	...	@@ -1208,7 +1208,7 @@
1208	1208	/* Update the fsid? */
1209	1209	if (S_ISDIR(inode->i_mode) && (fattr->valid & NFS_ATTR_FATTR_FSID) &&
1210	1210	!nfs_fsid_equal(&server->fsid, &fattr->fsid) &&
1211		- !test_bit(NFS_INO_MOUNTPOINT, &nfsi->flags))
	1211	+ !IS_AUTOMOUNT(inode))
1212	1212	server->fsid = fattr->fsid;
1213	1213
1214	1214	/*
...	...	@@ -252,6 +252,7 @@
252	252	const struct dentry *droot,
253	253	const struct dentry *dentry,
254	254	char *buffer, ssize_t buflen);
	255	+extern struct vfsmount nfs_d_automount(struct path path);
255	256
256	257	/* getroot.c */
257	258	extern struct dentry nfs_get_root(struct super_block , struct nfs_fh *);
...	...	@@ -97,9 +97,8 @@
97	97	}
98	98
99	99	/*
100		- * nfs_follow_mountpoint - handle crossing a mountpoint on the server
101		- * @dentry - dentry of mountpoint
102		- * @nd - nameidata info
	100	+ * nfs_d_automount - Handle crossing a mountpoint on the server
	101	+ * @path - The mountpoint
103	102	*
104	103	* When we encounter a mountpoint on the server, we want to set up
105	104	* a mountpoint on the client too, to prevent inode numbers from
106	105
107	106
108	107
109	108
110	109
111	110
112	111
113	112
114	113
115	114
116	115
117	116
118	117
119	118
120	119
121	120
122	121
123	122
124	123
...	...	@@ -109,84 +108,81 @@
109	108	* situation, and that different filesystems may want to use
110	109	* different security flavours.
111	110	*/
112		-static void * nfs_follow_mountpoint(struct dentry dentry, struct nameidata nd)
	111	+struct vfsmount nfs_d_automount(struct path path)
113	112	{
114	113	struct vfsmount *mnt;
115		- struct nfs_server *server = NFS_SERVER(dentry->d_inode);
	114	+ struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
116	115	struct dentry *parent;
117	116	struct nfs_fh *fh = NULL;
118	117	struct nfs_fattr *fattr = NULL;
119	118	int err;
120	119
121		- dprintk("--> nfs_follow_mountpoint()\n");
	120	+ dprintk("--> nfs_d_automount()\n");
122	121
123		- err = -ESTALE;
124		- if (IS_ROOT(dentry))
125		- goto out_err;
	122	+ mnt = ERR_PTR(-ESTALE);
	123	+ if (IS_ROOT(path->dentry))
	124	+ goto out_nofree;
126	125
127		- err = -ENOMEM;
	126	+ mnt = ERR_PTR(-ENOMEM);
128	127	fh = nfs_alloc_fhandle();
129	128	fattr = nfs_alloc_fattr();
130	129	if (fh == NULL \|\| fattr == NULL)
131		- goto out_err;
	130	+ goto out;
132	131
133	132	dprintk("%s: enter\n", __func__);
134		- dput(nd->path.dentry);
135		- nd->path.dentry = dget(dentry);
136	133
137		- /* Look it up again */
138		- parent = dget_parent(nd->path.dentry);
	134	+ /* Look it up again to get its attributes */
	135	+ parent = dget_parent(path->dentry);
139	136	err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
140		- &nd->path.dentry->d_name,
	137	+ &path->dentry->d_name,
141	138	fh, fattr);
142	139	dput(parent);
143		- if (err != 0)
144		- goto out_err;
	140	+ if (err != 0) {
	141	+ mnt = ERR_PTR(err);
	142	+ goto out;
	143	+ }
145	144
146	145	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
147		- mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry);
	146	+ mnt = nfs_do_refmount(path->mnt, path->dentry);
148	147	else
149		- mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, fh,
150		- fattr);
151		- err = PTR_ERR(mnt);
	148	+ mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr);
152	149	if (IS_ERR(mnt))
153		- goto out_err;
	150	+ goto out;
154	151
155	152	mntget(mnt);
156		- err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags\|MNT_SHRINKABLE,
	153	+ err = do_add_mount(mnt, path, path->mnt->mnt_flags \| MNT_SHRINKABLE,
157	154	&nfs_automount_list);
158		- if (err < 0) {
	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 */
159	162	mntput(mnt);
160		- if (err == -EBUSY)
161		- goto out_follow;
162		- goto out_err;
	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;
163	171	}
164		- path_put(&nd->path);
165		- nd->path.mnt = mnt;
166		- nd->path.dentry = dget(mnt->mnt_root);
167		- schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
	172	+
168	173	out:
169	174	nfs_free_fattr(fattr);
170	175	nfs_free_fhandle(fh);
171		- dprintk("%s: done, returned %d\n", __func__, err);
172		-
173		- dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
174		- return ERR_PTR(err);
175		-out_err:
176		- path_put(&nd->path);
177		- goto out;
178		-out_follow:
179		- err = follow_down(&nd->path, false);
180		- goto out;
	176	+out_nofree:
	177	+ dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt);
	178	+ return mnt;
181	179	}
182	180
183	181	const struct inode_operations nfs_mountpoint_inode_operations = {
184		- .follow_link = nfs_follow_mountpoint,
185	182	.getattr = nfs_getattr,
186	183	};
187	184
188	185	const struct inode_operations nfs_referral_inode_operations = {
189		- .follow_link = nfs_follow_mountpoint,
190	186	};
191	187
192	188	static void nfs_expire_automounts(struct work_struct *work)
...	...	@@ -215,7 +215,6 @@
215	215	#define NFS_INO_ADVISE_RDPLUS (0) /* advise readdirplus */
216	216	#define NFS_INO_STALE (1) /* possible stale inode */
217	217	#define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */
218		-#define NFS_INO_MOUNTPOINT (3) /* inode is remote mountpoint */
219	218	#define NFS_INO_FLUSHING (4) /* inode is flushing out data */
220	219	#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */
221	220	#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */