1 files changed, 66 insertions, 50 deletions

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index a1cb5afe6801..057cf11326bf 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -23,6 +23,7 @@
 #include <linux/cred.h>
 #include <linux/sched.h>
 #include <linux/init_task.h>
+#include <linux/slab.h>
 
 static struct vfsmount *dev_mnt;
 
@@ -32,6 +33,8 @@ static int dev_mount = 1;
 static int dev_mount;
 #endif
 
+static DEFINE_MUTEX(dirlock);
+
 static int __init mount_param(char *str)
 {
         dev_mount = simple_strtoul(str, NULL, 0);
@@ -74,47 +77,37 @@ static int dev_mkdir(const char *name, mode_t mode)
         dentry = lookup_create(&nd, 1);
         if (!IS_ERR(dentry)) {
                 err = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
+                if (!err)
+                        /* mark as kernel-created inode */
+                        dentry->d_inode->i_private = &dev_mnt;
                 dput(dentry);
         } else {
                 err = PTR_ERR(dentry);
         }
-        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 
+        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
         path_put(&nd.path);
         return err;
 }
 
 static int create_path(const char *nodepath)
 {
-        char *path;
-        struct nameidata nd;
-        int err = 0;
-
-        path = kstrdup(nodepath, GFP_KERNEL);
-        if (!path)
-                return -ENOMEM;
-
-        err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
-                              path, LOOKUP_PARENT, &nd);
-        if (err == 0) {
-                struct dentry *dentry;
-
-                /* create directory right away */
-                dentry = lookup_create(&nd, 1);
-                if (!IS_ERR(dentry)) {
-                        err = vfs_mkdir(nd.path.dentry->d_inode,
-                                        dentry, 0755);
-                        dput(dentry);
-                }
-                mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+        int err;
 
-                path_put(&nd.path);
-        } else if (err == -ENOENT) {
+        mutex_lock(&dirlock);
+        err = dev_mkdir(nodepath, 0755);
+        if (err == -ENOENT) {
+                char *path;
                 char *s;
 
                 /* parent directories do not exist, create them */
+                path = kstrdup(nodepath, GFP_KERNEL);
+                if (!path) {
+                        err = -ENOMEM;
+                        goto out;
+                }
                 s = path;
-                while (1) {
+                for (;;) {
                         s = strchr(s, '/');
                         if (!s)
                                 break;
@@ -125,9 +118,10 @@ static int create_path(const char *nodepath)
                         s[0] = '/';
                         s++;
                 }
+                kfree(path);
         }
-
-        kfree(path);
+out:
+        mutex_unlock(&dirlock);
         return err;
 }
 
@@ -156,34 +150,40 @@ int devtmpfs_create_node(struct device *dev)
                 mode |= S_IFCHR;
 
         curr_cred = override_creds(&init_cred);
+
         err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
                               nodename, LOOKUP_PARENT, &nd);
         if (err == -ENOENT) {
-                /* create missing parent directories */
                 create_path(nodename);
                 err = vfs_path_lookup(dev_mnt->mnt_root, dev_mnt,
                                       nodename, LOOKUP_PARENT, &nd);
-                if (err)
-                        goto out;
         }
+        if (err)
+                goto out;
 
         dentry = lookup_create(&nd, 0);
         if (!IS_ERR(dentry)) {
-                int umask;
-
-                umask = sys_umask(0000);
                 err = vfs_mknod(nd.path.dentry->d_inode,
                                 dentry, mode, dev->devt);
-                sys_umask(umask);
-                /* mark as kernel created inode */
-                if (!err)
+                if (!err) {
+                        struct iattr newattrs;
+
+                        /* fixup possibly umasked mode */
+                        newattrs.ia_mode = mode;
+                        newattrs.ia_valid = ATTR_MODE;
+                        mutex_lock(&dentry->d_inode->i_mutex);
+                        notify_change(dentry, &newattrs);
+                        mutex_unlock(&dentry->d_inode->i_mutex);
+
+                        /* mark as kernel-created inode */
                         dentry->d_inode->i_private = &dev_mnt;
+                }
                 dput(dentry);
         } else {
                 err = PTR_ERR(dentry);
         }
-        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 
+        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
         path_put(&nd.path);
 out:
         kfree(tmp);
@@ -205,16 +205,21 @@ static int dev_rmdir(const char *name)
         mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
         dentry = lookup_one_len(nd.last.name, nd.path.dentry, nd.last.len);
         if (!IS_ERR(dentry)) {
-                if (dentry->d_inode)
-                        err = vfs_rmdir(nd.path.dentry->d_inode, dentry);
-                else
+                if (dentry->d_inode) {
+                        if (dentry->d_inode->i_private == &dev_mnt)
+                                err = vfs_rmdir(nd.path.dentry->d_inode,
+                                                dentry);
+                        else
+                                err = -EPERM;
+                } else {
                         err = -ENOENT;
+                }
                 dput(dentry);
         } else {
                 err = PTR_ERR(dentry);
         }
-        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
 
+        mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
         path_put(&nd.path);
         return err;
 }
@@ -228,7 +233,8 @@ static int delete_path(const char *nodepath)
         if (!path)
                 return -ENOMEM;
 
-        while (1) {
+        mutex_lock(&dirlock);
+        for (;;) {
                 char *base;
 
                 base = strrchr(path, '/');
@@ -239,6 +245,7 @@ static int delete_path(const char *nodepath)
                 if (err)
                         break;
         }
+        mutex_unlock(&dirlock);
 
         kfree(path);
         return err;
@@ -295,6 +302,19 @@ int devtmpfs_delete_node(struct device *dev)
                 if (dentry->d_inode) {
                         err = vfs_getattr(nd.path.mnt, dentry, &stat);
                         if (!err && dev_mynode(dev, dentry->d_inode, &stat)) {
+                                struct iattr newattrs;
+                                /*
+                                 * before unlinking this node, reset permissions
+                                 * of possible references like hardlinks
+                                 */
+                                newattrs.ia_uid = 0;
+                                newattrs.ia_gid = 0;
+                                newattrs.ia_mode = stat.mode & ~0777;
+                                newattrs.ia_valid =
+                                        ATTR_UID|ATTR_GID|ATTR_MODE;
+                                mutex_lock(&dentry->d_inode->i_mutex);
+                                notify_change(dentry, &newattrs);
+                                mutex_unlock(&dentry->d_inode->i_mutex);
                                 err = vfs_unlink(nd.path.dentry->d_inode,
                                                  dentry);
                                 if (!err || err == -ENOENT)
@@ -322,9 +342,8 @@ out:
  * If configured, or requested by the commandline, devtmpfs will be
  * auto-mounted after the kernel mounted the root filesystem.
  */
-int devtmpfs_mount(const char *mountpoint)
+int devtmpfs_mount(const char *mntdir)
 {
-        struct path path;
         int err;
 
         if (!dev_mount)
@@ -333,15 +352,11 @@ int devtmpfs_mount(const char *mountpoint)
         if (!dev_mnt)
                 return 0;
 
-        err = kern_path(mountpoint, LOOKUP_FOLLOW, &path);
-        if (err)
-                return err;
-        err = do_add_mount(dev_mnt, &path, 0, NULL);
+        err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL);
         if (err)
                 printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
         else
                 printk(KERN_INFO "devtmpfs: mounted\n");
-        path_put(&path);
         return err;
 }
 
@@ -353,6 +368,7 @@ int __init devtmpfs_init(void)
 {
         int err;
         struct vfsmount *mnt;
+        char options[] = "mode=0755";
 
         err = register_filesystem(&dev_fs_type);
         if (err) {
@@ -361,7 +377,7 @@ int __init devtmpfs_init(void)
                 return err;
         }
 
-        mnt = kern_mount(&dev_fs_type);
+        mnt = kern_mount_data(&dev_fs_type, options);
         if (IS_ERR(mnt)) {
                 err = PTR_ERR(mnt);
                 printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);