[PATCH] kill altroot

long overdue...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 4 insertions, 96 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 6c76e1ee9c45..095818089ac1 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -31,7 +31,6 @@
 #include <linux/file.h>
 #include <linux/fcntl.h>
 #include <linux/device_cgroup.h>
-#include <asm/namei.h>
 #include <asm/uaccess.h>
 
 #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
@@ -562,27 +561,16 @@ out_unlock:
         return result;
 }
 
-static int __emul_lookup_dentry(const char *, struct nameidata *);
-
 /* SMP-safe */
-static __always_inline int
+static __always_inline void
 walk_init_root(const char *name, struct nameidata *nd)
 {
         struct fs_struct *fs = current->fs;
 
         read_lock(&fs->lock);
-        if (fs->altroot.dentry && !(nd->flags & LOOKUP_NOALT)) {
-                nd->path = fs->altroot;
-                path_get(&fs->altroot);
-                read_unlock(&fs->lock);
-                if (__emul_lookup_dentry(name,nd))
-                        return 0;
-                read_lock(&fs->lock);
-        }
         nd->path = fs->root;
         path_get(&fs->root);
         read_unlock(&fs->lock);
-        return 1;
 }
 
 /*
@@ -623,12 +611,9 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
 
         if (*link == '/') {
                 path_put(&nd->path);
-                if (!walk_init_root(link, nd))
-                        /* weird __emul_prefix() stuff did it */
-                        goto out;
+                walk_init_root(link, nd);
         }
         res = link_path_walk(link, nd);
-out:
         if (nd->depth || res || nd->last_type!=LAST_NORM)
                 return res;
         /*
@@ -1077,67 +1062,6 @@ static int path_walk(const char *name, struct nameidata *nd)
         return link_path_walk(name, nd);
 }
 
-/* 
- * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
- * everything is done. Returns 0 and drops input nd, if lookup failed;
- */
-static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
-{
-        if (path_walk(name, nd))
-                return 0;               /* something went wrong... */
-
-        if (!nd->path.dentry->d_inode ||
-            S_ISDIR(nd->path.dentry->d_inode->i_mode)) {
-                struct path old_path = nd->path;
-                struct qstr last = nd->last;
-                int last_type = nd->last_type;
-                struct fs_struct *fs = current->fs;
-
-                /*
-                 * NAME was not found in alternate root or it's a directory.
-                 * Try to find it in the normal root:
-                 */
-                nd->last_type = LAST_ROOT;
-                read_lock(&fs->lock);
-                nd->path = fs->root;
-                path_get(&fs->root);
-                read_unlock(&fs->lock);
-                if (path_walk(name, nd) == 0) {
-                        if (nd->path.dentry->d_inode) {
-                                path_put(&old_path);
-                                return 1;
-                        }
-                        path_put(&nd->path);
-                }
-                nd->path = old_path;
-                nd->last = last;
-                nd->last_type = last_type;
-        }
-        return 1;
-}
-
-void set_fs_altroot(void)
-{
-        char *emul = __emul_prefix();
-        struct nameidata nd;
-        struct path path = {}, old_path;
-        int err;
-        struct fs_struct *fs = current->fs;
-
-        if (!emul)
-                goto set_it;
-        err = path_lookup(emul, LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOALT, &nd);
-        if (!err)
-                path = nd.path;
-set_it:
-        write_lock(&fs->lock);
-        old_path = fs->altroot;
-        fs->altroot = path;
-        write_unlock(&fs->lock);
-        if (old_path.dentry)
-                path_put(&old_path);
-}
-
 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
 static int do_path_lookup(int dfd, const char *name,
                                 unsigned int flags, struct nameidata *nd)
@@ -1153,14 +1077,6 @@ static int do_path_lookup(int dfd, const char *name,
 
         if (*name=='/') {
                 read_lock(&fs->lock);
-                if (fs->altroot.dentry && !(nd->flags & LOOKUP_NOALT)) {
-                        nd->path = fs->altroot;
-                        path_get(&fs->altroot);
-                        read_unlock(&fs->lock);
-                        if (__emul_lookup_dentry(name,nd))
-                                goto out; /* found in altroot */
-                        read_lock(&fs->lock);
-                }
                 nd->path = fs->root;
                 path_get(&fs->root);
                 read_unlock(&fs->lock);
@@ -1194,7 +1110,6 @@ static int do_path_lookup(int dfd, const char *name,
         }
 
         retval = path_walk(name, nd);
-out:
         if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
                                 nd->path.dentry->d_inode))
                 audit_inode(name, nd->path.dentry);
diff --git a/fs/namespace.c b/fs/namespace.c
index f30b11e2240e..c4fcf48acef8 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1972,7 +1972,7 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
                 struct fs_struct *fs)
 {
         struct mnt_namespace *new_ns;
-        struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL;
+        struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
         struct vfsmount *p, *q;
 
         new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
@@ -2015,10 +2015,6 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
                                 pwdmnt = p;
                                 fs->pwd.mnt = mntget(q);
                         }
-                        if (p == fs->altroot.mnt) {
-                                altrootmnt = p;
-                                fs->altroot.mnt = mntget(q);
-                        }
                 }
                 p = next_mnt(p, mnt_ns->root);
                 q = next_mnt(q, new_ns->root);
@@ -2029,8 +2025,6 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
                 mntput(rootmnt);
         if (pwdmnt)
                 mntput(pwdmnt);
-        if (altrootmnt)
-                mntput(altrootmnt);
 
         return new_ns;
 }
diff --git a/fs/open.c b/fs/open.c
index 8e02d42bfe44..d3a2a00f52dc 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -548,7 +548,7 @@ asmlinkage long sys_chroot(const char __user * filename)
         struct nameidata nd;
         int error;
 
-        error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY | LOOKUP_NOALT, &nd);
+        error = __user_walk(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
         if (error)
                 goto out;
 
@@ -561,7 +561,6 @@ asmlinkage long sys_chroot(const char __user * filename)
                 goto dput_and_out;
 
         set_fs_root(current->fs, &nd.path);
-        set_fs_altroot();
         error = 0;
 dput_and_out:
         path_put(&nd.path);