vfs: change d_manage() to take a struct path

For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Link: http://lkml.kernel.org/r/20161011053352.27645.83962.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 1b5f15653b1bb82ca0fc7801fe01fe8c4c75047a..4ca3a8d1349d1f95f8a4c7c3ea2627f230ab0498 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -20,7 +20,7 @@ prototypes:
        void (*d_iput)(struct dentry *, struct inode *);
        char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
        struct vfsmount *(*d_automount)(struct path *path);
-       int (*d_manage)(struct dentry *, bool);
+       int (*d_manage)(const struct path *, bool);
        struct dentry *(*d_real)(struct dentry *, const struct inode *,
                                 unsigned int);
 

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index b5039a00caafae44660514da3829994436a35e84..3893f4d44cd46e0c7b9579fad48638a0fe359960 100644 (file)
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -948,7 +948,7 @@ struct dentry_operations {
        void (*d_iput)(struct dentry *, struct inode *);
        char *(*d_dname)(struct dentry *, char *, int);
        struct vfsmount *(*d_automount)(struct path *);
-       int (*d_manage)(struct dentry *, bool);
+       int (*d_manage)(const struct path *, bool);
        struct dentry *(*d_real)(struct dentry *, const struct inode *,
                                 unsigned int);
 };

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index a11f7317487773617dd585197e7482f5e22a3045..3a4328218b71d9d87fe429fa7e3cc162135e66ae 100644 (file)
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -32,7 +32,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file);
 static struct dentry *autofs4_lookup(struct inode *,
                                     struct dentry *, unsigned int);
 static struct vfsmount *autofs4_d_automount(struct path *);
-static int autofs4_d_manage(struct dentry *, bool);
+static int autofs4_d_manage(const struct path *, bool);
 static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
@@ -421,8 +421,9 @@ done:
        return NULL;
 }
 
-static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+static int autofs4_d_manage(const struct path *path, bool rcu_walk)
 {
+       struct dentry *dentry = path->dentry;
        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
        struct autofs_info *ino = autofs4_dentry_ino(dentry);
        int status;

diff --git a/fs/namei.c b/fs/namei.c
index 5b4eed2215304a14ac2614058ae2b2002a3f2ae9..81ac4736b596f4d15fa1df2871911e22f3ba6c19 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1200,7 +1200,7 @@ static int follow_managed(struct path *path, struct nameidata *nd)
                if (managed & DCACHE_MANAGE_TRANSIT) {
                        BUG_ON(!path->dentry->d_op);
                        BUG_ON(!path->dentry->d_op->d_manage);
-                       ret = path->dentry->d_op->d_manage(path->dentry, false);
+                       ret = path->dentry->d_op->d_manage(path, false);
                        if (ret < 0)
                                break;
                }
@@ -1263,10 +1263,10 @@ int follow_down_one(struct path *path)
 }
 EXPORT_SYMBOL(follow_down_one);
 
-static inline int managed_dentry_rcu(struct dentry *dentry)
+static inline int managed_dentry_rcu(const struct path *path)
 {
-       return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
-               dentry->d_op->d_manage(dentry, true) : 0;
+       return (path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) ?
+               path->dentry->d_op->d_manage(path, true) : 0;
 }
 
 /*
@@ -1282,7 +1282,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
                 * Don't forget we might have a non-mountpoint managed dentry
                 * that wants to block transit.
                 */
-               switch (managed_dentry_rcu(path->dentry)) {
+               switch (managed_dentry_rcu(path)) {
                case -ECHILD:
                default:
                        return false;
@@ -1392,8 +1392,7 @@ int follow_down(struct path *path)
                if (managed & DCACHE_MANAGE_TRANSIT) {
                        BUG_ON(!path->dentry->d_op);
                        BUG_ON(!path->dentry->d_op->d_manage);
-                       ret = path->dentry->d_op->d_manage(
-                               path->dentry, false);
+                       ret = path->dentry->d_op->d_manage(path, false);
                        if (ret < 0)
                                return ret == -EISDIR ? 0 : ret;
                }

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 5beed7b30561119cf66e5f8aa0779d54cd602d3c..bc529ce88ed0924f49c25c5fbc34fa655b5590f2 100644 (file)
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -139,7 +139,7 @@ struct dentry_operations {
        void (*d_iput)(struct dentry *, struct inode *);
        char *(*d_dname)(struct dentry *, char *, int);
        struct vfsmount *(*d_automount)(struct path *);
-       int (*d_manage)(struct dentry *, bool);
+       int (*d_manage)(const struct path *, bool);
        struct dentry *(*d_real)(struct dentry *, const struct inode *,
                                 unsigned int);
 } ____cacheline_aligned;