5 files changed, 256 insertions, 299 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 797d775e0354..0d6eb33597c6 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -80,6 +80,7 @@
 #include <linux/delayacct.h>
 #include <linux/seq_file.h>
 #include <linux/pid_namespace.h>
+#include <linux/tracehook.h>
 
 #include <asm/pgtable.h>
 #include <asm/processor.h>
@@ -168,8 +169,12 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
         rcu_read_lock();
         ppid = pid_alive(p) ?
                 task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
-        tpid = pid_alive(p) && p->ptrace ?
-                task_pid_nr_ns(rcu_dereference(p->parent), ns) : 0;
+        tpid = 0;
+        if (pid_alive(p)) {
+                struct task_struct *tracer = tracehook_tracer_task(p);
+                if (tracer)
+                        tpid = task_pid_nr_ns(tracer, ns);
+        }
         seq_printf(m,
                 "State:\t%s\n"
                 "Tgid:\t%d\n"
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a891fe4cb43b..01ed610f9b87 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -53,6 +53,7 @@
 #include <linux/time.h>
 #include <linux/proc_fs.h>
 #include <linux/stat.h>
+#include <linux/task_io_accounting_ops.h>
 #include <linux/init.h>
 #include <linux/capability.h>
 #include <linux/file.h>
@@ -69,6 +70,7 @@
 #include <linux/mount.h>
 #include <linux/security.h>
 #include <linux/ptrace.h>
+#include <linux/tracehook.h>
 #include <linux/cgroup.h>
 #include <linux/cpuset.h>
 #include <linux/audit.h>
@@ -231,10 +233,14 @@ static int check_mem_permission(struct task_struct *task)
          * If current is actively ptrace'ing, and would also be
          * permitted to freshly attach with ptrace now, permit it.
          */
-        if (task->parent == current && (task->ptrace & PT_PTRACED) &&
-            task_is_stopped_or_traced(task) &&
-            ptrace_may_access(task, PTRACE_MODE_ATTACH))
-                return 0;
+        if (task_is_stopped_or_traced(task)) {
+                int match;
+                rcu_read_lock();
+                match = (tracehook_tracer_task(task) == current);
+                rcu_read_unlock();
+                if (match && ptrace_may_access(task, PTRACE_MODE_ATTACH))
+                        return 0;
+        }
 
         /*
          * Noone else is allowed.
@@ -504,6 +510,26 @@ static int proc_pid_limits(struct task_struct *task, char *buffer)
         return count;
 }
 
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+static int proc_pid_syscall(struct task_struct *task, char *buffer)
+{
+        long nr;
+        unsigned long args[6], sp, pc;
+
+        if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
+                return sprintf(buffer, "running\n");
+
+        if (nr < 0)
+                return sprintf(buffer, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
+
+        return sprintf(buffer,
+                       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
+                       nr,
+                       args[0], args[1], args[2], args[3], args[4], args[5],
+                       sp, pc);
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
+
 /************************************************************************/
 /*                       Here the fs part begins                        */
 /************************************************************************/
@@ -1834,8 +1860,7 @@ static const struct file_operations proc_fd_operations = {
  * /proc/pid/fd needs a special permission handler so that a process can still
  * access /proc/self/fd after it has executed a setuid().
  */
-static int proc_fd_permission(struct inode *inode, int mask,
-                                struct nameidata *nd)
+static int proc_fd_permission(struct inode *inode, int mask)
 {
         int rv;
 
@@ -2378,53 +2403,18 @@ static int proc_base_fill_cache(struct file *filp, void *dirent,
 #ifdef CONFIG_TASK_IO_ACCOUNTING
 static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
 {
-        u64 rchar, wchar, syscr, syscw;
-        struct task_io_accounting ioac;
-
-        if (!whole) {
-                rchar = task->rchar;
-                wchar = task->wchar;
-                syscr = task->syscr;
-                syscw = task->syscw;
-                memcpy(&ioac, &task->ioac, sizeof(ioac));
-        } else {
-                unsigned long flags;
-                struct task_struct *t = task;
-                rchar = wchar = syscr = syscw = 0;
-                memset(&ioac, 0, sizeof(ioac));
-
-                rcu_read_lock();
-                do {
-                        rchar += t->rchar;
-                        wchar += t->wchar;
-                        syscr += t->syscr;
-                        syscw += t->syscw;
-
-                        ioac.read_bytes += t->ioac.read_bytes;
-                        ioac.write_bytes += t->ioac.write_bytes;
-                        ioac.cancelled_write_bytes +=
-                                        t->ioac.cancelled_write_bytes;
-                        t = next_thread(t);
-                } while (t != task);
-                rcu_read_unlock();
-
-                if (lock_task_sighand(task, &flags)) {
-                        struct signal_struct *sig = task->signal;
+        struct task_io_accounting acct = task->ioac;
+        unsigned long flags;
 
-                        rchar += sig->rchar;
-                        wchar += sig->wchar;
-                        syscr += sig->syscr;
-                        syscw += sig->syscw;
+        if (whole && lock_task_sighand(task, &flags)) {
+                struct task_struct *t = task;
 
-                        ioac.read_bytes += sig->ioac.read_bytes;
-                        ioac.write_bytes += sig->ioac.write_bytes;
-                        ioac.cancelled_write_bytes +=
-                                        sig->ioac.cancelled_write_bytes;
+                task_io_accounting_add(&acct, &task->signal->ioac);
+                while_each_thread(task, t)
+                        task_io_accounting_add(&acct, &t->ioac);
 
-                        unlock_task_sighand(task, &flags);
-                }
+                unlock_task_sighand(task, &flags);
         }
-
         return sprintf(buffer,
                         "rchar: %llu\n"
                         "wchar: %llu\n"
@@ -2433,13 +2423,10 @@ static int do_io_accounting(struct task_struct *task, char *buffer, int whole)
                         "read_bytes: %llu\n"
                         "write_bytes: %llu\n"
                         "cancelled_write_bytes: %llu\n",
-                        (unsigned long long)rchar,
-                        (unsigned long long)wchar,
-                        (unsigned long long)syscr,
-                        (unsigned long long)syscw,
-                        (unsigned long long)ioac.read_bytes,
-                        (unsigned long long)ioac.write_bytes,
-                        (unsigned long long)ioac.cancelled_write_bytes);
+                        acct.rchar, acct.wchar,
+                        acct.syscr, acct.syscw,
+                        acct.read_bytes, acct.write_bytes,
+                        acct.cancelled_write_bytes);
 }
 
 static int proc_tid_io_accounting(struct task_struct *task, char *buffer)
@@ -2473,6 +2460,9 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_SCHED_DEBUG
         REG("sched",      S_IRUGO|S_IWUSR, pid_sched),
 #endif
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+        INF("syscall",    S_IRUSR, pid_syscall),
+#endif
         INF("cmdline",    S_IRUGO, pid_cmdline),
         ONE("stat",       S_IRUGO, tgid_stat),
         ONE("statm",      S_IRUGO, pid_statm),
@@ -2805,6 +2795,9 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_SCHED_DEBUG
         REG("sched",     S_IRUGO|S_IWUSR, pid_sched),
 #endif
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+        INF("syscall",   S_IRUSR, pid_syscall),
+#endif
         INF("cmdline",   S_IRUGO, pid_cmdline),
         ONE("stat",      S_IRUGO, tid_stat),
         ONE("statm",     S_IRUGO, pid_statm),
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index bc0a0dd2d844..cb4096cc3fb7 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -806,12 +806,9 @@ continue_removing:
         if (S_ISDIR(de->mode))
                 parent->nlink--;
         de->nlink = 0;
-        if (de->subdir) {
-                printk(KERN_WARNING "%s: removing non-empty directory "
+        WARN(de->subdir, KERN_WARNING "%s: removing non-empty directory "
                         "'%s/%s', leaking at least '%s'\n", __func__,
                         de->parent->name, de->name, de->subdir->name);
-                WARN_ON(1);
-        }
         if (atomic_dec_and_test(&de->count))
                 free_proc_entry(de);
 }
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 02eca2ed9dd7..8bb03f056c28 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/smp_lock.h>
+#include <linux/sysctl.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -65,6 +66,8 @@ static void proc_delete_inode(struct inode *inode)
                         module_put(de->owner);
                 de_put(de);
         }
+        if (PROC_I(inode)->sysctl)
+                sysctl_head_put(PROC_I(inode)->sysctl);
         clear_inode(inode);
 }
 
@@ -84,6 +87,8 @@ static struct inode *proc_alloc_inode(struct super_block *sb)
         ei->fd = 0;
         ei->op.proc_get_link = NULL;
         ei->pde = NULL;
+        ei->sysctl = NULL;
+        ei->sysctl_entry = NULL;
         inode = &ei->vfs_inode;
         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
         return inode;
@@ -94,7 +99,7 @@ static void proc_destroy_inode(struct inode *inode)
         kmem_cache_free(proc_inode_cachep, PROC_I(inode));
 }
 
-static void init_once(struct kmem_cache * cachep, void *foo)
+static void init_once(void *foo)
 {
         struct proc_inode *ei = (struct proc_inode *) foo;
 
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 5acc001d49f6..f9a8b892718f 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -10,149 +10,110 @@
 static struct dentry_operations proc_sys_dentry_operations;
 static const struct file_operations proc_sys_file_operations;
 static const struct inode_operations proc_sys_inode_operations;
+static const struct file_operations proc_sys_dir_file_operations;
+static const struct inode_operations proc_sys_dir_operations;
 
-static void proc_sys_refresh_inode(struct inode *inode, struct ctl_table *table)
-{
-        /* Refresh the cached information bits in the inode */
-        if (table) {
-                inode->i_uid = 0;
-                inode->i_gid = 0;
-                inode->i_mode = table->mode;
-                if (table->proc_handler) {
-                        inode->i_mode |= S_IFREG;
-                        inode->i_nlink = 1;
-                } else {
-                        inode->i_mode |= S_IFDIR;
-                        inode->i_nlink = 0;     /* It is too hard to figure out */
-                }
-        }
-}
-
-static struct inode *proc_sys_make_inode(struct inode *dir, struct ctl_table *table)
+static struct inode *proc_sys_make_inode(struct super_block *sb,
+                struct ctl_table_header *head, struct ctl_table *table)
 {
         struct inode *inode;
-        struct proc_inode *dir_ei, *ei;
-        int depth;
+        struct proc_inode *ei;
 
-        inode = new_inode(dir->i_sb);
+        inode = new_inode(sb);
         if (!inode)
                 goto out;
 
-        /* A directory is always one deeper than it's parent */
-        dir_ei = PROC_I(dir);
-        depth = dir_ei->fd + 1;
-
+        sysctl_head_get(head);
         ei = PROC_I(inode);
-        ei->fd = depth;
+        ei->sysctl = head;
+        ei->sysctl_entry = table;
+
         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-        inode->i_op = &proc_sys_inode_operations;
-        inode->i_fop = &proc_sys_file_operations;
         inode->i_flags |= S_PRIVATE; /* tell selinux to ignore this inode */
-        proc_sys_refresh_inode(inode, table);
+        inode->i_mode = table->mode;
+        if (!table->child) {
+                inode->i_mode |= S_IFREG;
+                inode->i_op = &proc_sys_inode_operations;
+                inode->i_fop = &proc_sys_file_operations;
+        } else {
+                inode->i_mode |= S_IFDIR;
+                inode->i_nlink = 0;
+                inode->i_op = &proc_sys_dir_operations;
+                inode->i_fop = &proc_sys_dir_file_operations;
+        }
 out:
         return inode;
 }
 
-static struct dentry *proc_sys_ancestor(struct dentry *dentry, int depth)
-{
-        for (;;) {
-                struct proc_inode *ei;
-
-                ei = PROC_I(dentry->d_inode);
-                if (ei->fd == depth)
-                        break; /* found */
-
-                dentry = dentry->d_parent;
-        }
-        return dentry;
-}
-
-static struct ctl_table *proc_sys_lookup_table_one(struct ctl_table *table,
-                                                        struct qstr *name)
+static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
 {
         int len;
-        for ( ; table->ctl_name || table->procname; table++) {
+        for ( ; p->ctl_name || p->procname; p++) {
 
-                if (!table->procname)
+                if (!p->procname)
                         continue;
 
-                len = strlen(table->procname);
+                len = strlen(p->procname);
                 if (len != name->len)
                         continue;
 
-                if (memcmp(table->procname, name->name, len) != 0)
+                if (memcmp(p->procname, name->name, len) != 0)
                         continue;
 
                 /* I have a match */
-                return table;
+                return p;
         }
         return NULL;
 }
 
-static struct ctl_table *proc_sys_lookup_table(struct dentry *dentry,
-                                                struct ctl_table *table)
+struct ctl_table_header *grab_header(struct inode *inode)
 {
-        struct dentry *ancestor;
-        struct proc_inode *ei;
-        int depth, i;
+        if (PROC_I(inode)->sysctl)
+                return sysctl_head_grab(PROC_I(inode)->sysctl);
+        else
+                return sysctl_head_next(NULL);
+}
 
-        ei = PROC_I(dentry->d_inode);
-        depth = ei->fd;
+static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
+                                        struct nameidata *nd)
+{
+        struct ctl_table_header *head = grab_header(dir);
+        struct ctl_table *table = PROC_I(dir)->sysctl_entry;
+        struct ctl_table_header *h = NULL;
+        struct qstr *name = &dentry->d_name;
+        struct ctl_table *p;
+        struct inode *inode;
+        struct dentry *err = ERR_PTR(-ENOENT);
 
-        if (depth == 0)
-                return table;
+        if (IS_ERR(head))
+                return ERR_CAST(head);
 
-        for (i = 1; table && (i <= depth); i++) {
-                ancestor = proc_sys_ancestor(dentry, i);
-                table = proc_sys_lookup_table_one(table, &ancestor->d_name);
-                if (table)
-                        table = table->child;
+        if (table && !table->child) {
+                WARN_ON(1);
+                goto out;
         }
-        return table;
-
-}
-static struct ctl_table *proc_sys_lookup_entry(struct dentry *dparent,
-                                                struct qstr *name,
-                                                struct ctl_table *table)
-{
-        table = proc_sys_lookup_table(dparent, table);
-        if (table)
-                table = proc_sys_lookup_table_one(table, name);
-        return table;
-}
 
-static struct ctl_table *do_proc_sys_lookup(struct dentry *parent,
-                                                struct qstr *name,
-                                                struct ctl_table_header **ptr)
-{
-        struct ctl_table_header *head;
-        struct ctl_table *table = NULL;
+        table = table ? table->child : head->ctl_table;
 
-        for (head = sysctl_head_next(NULL); head;
-                        head = sysctl_head_next(head)) {
-                table = proc_sys_lookup_entry(parent, name, head->ctl_table);
-                if (table)
-                        break;
+        p = find_in_table(table, name);
+        if (!p) {
+                for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
+                        if (h->attached_to != table)
+                                continue;
+                        p = find_in_table(h->attached_by, name);
+                        if (p)
+                                break;
+                }
         }
-        *ptr = head;
-        return table;
-}
-
-static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
-                                        struct nameidata *nd)
-{
-        struct ctl_table_header *head;
-        struct inode *inode;
-        struct dentry *err;
-        struct ctl_table *table;
 
-        err = ERR_PTR(-ENOENT);
-        table = do_proc_sys_lookup(dentry->d_parent, &dentry->d_name, &head);
-        if (!table)
+        if (!p)
                 goto out;
 
         err = ERR_PTR(-ENOMEM);
-        inode = proc_sys_make_inode(dir, table);
+        inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
+        if (h)
+                sysctl_head_finish(h);
+
         if (!inode)
                 goto out;
 
@@ -168,22 +129,14 @@ out:
 static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
                 size_t count, loff_t *ppos, int write)
 {
-        struct dentry *dentry = filp->f_dentry;
-        struct ctl_table_header *head;
-        struct ctl_table *table;
+        struct inode *inode = filp->f_path.dentry->d_inode;
+        struct ctl_table_header *head = grab_header(inode);
+        struct ctl_table *table = PROC_I(inode)->sysctl_entry;
         ssize_t error;
         size_t res;
 
-        table = do_proc_sys_lookup(dentry->d_parent, &dentry->d_name, &head);
-        /* Has the sysctl entry disappeared on us? */
-        error = -ENOENT;
-        if (!table)
-                goto out;
-
-        /* Has the sysctl entry been replaced by a directory? */
-        error = -EISDIR;
-        if (!table->proc_handler)
-                goto out;
+        if (IS_ERR(head))
+                return PTR_ERR(head);
 
         /*
          * At this point we know that the sysctl was not unregistered
@@ -193,6 +146,11 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
         if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
                 goto out;
 
+        /* if that can happen at all, it should be -EINVAL, not -EISDIR */
+        error = -EINVAL;
+        if (!table->proc_handler)
+                goto out;
+
         /* careful: calling conventions are nasty here */
         res = count;
         error = table->proc_handler(table, write, filp, buf, &res, ppos);
@@ -218,82 +176,86 @@ static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
 
 
 static int proc_sys_fill_cache(struct file *filp, void *dirent,
-                                filldir_t filldir, struct ctl_table *table)
+                                filldir_t filldir,
+                                struct ctl_table_header *head,
+                                struct ctl_table *table)
 {
-        struct ctl_table_header *head;
-        struct ctl_table *child_table = NULL;
         struct dentry *child, *dir = filp->f_path.dentry;
         struct inode *inode;
         struct qstr qname;
         ino_t ino = 0;
         unsigned type = DT_UNKNOWN;
-        int ret;
 
         qname.name = table->procname;
         qname.len  = strlen(table->procname);
         qname.hash = full_name_hash(qname.name, qname.len);
 
-        /* Suppress duplicates.
-         * Only fill a directory entry if it is the value that
-         * an ordinary lookup of that name returns.  Hide all
-         * others.
-         *
-         * If we ever cache this translation in the dcache
-         * I should do a dcache lookup first.  But for now
-         * it is just simpler not to.
-         */
-        ret = 0;
-        child_table = do_proc_sys_lookup(dir, &qname, &head);
-        sysctl_head_finish(head);
-        if (child_table != table)
-                return 0;
-
         child = d_lookup(dir, &qname);
         if (!child) {
-                struct dentry *new;
-                new = d_alloc(dir, &qname);
-                if (new) {
-                        inode = proc_sys_make_inode(dir->d_inode, table);
-                        if (!inode)
-                                child = ERR_PTR(-ENOMEM);
-                        else {
-                                new->d_op = &proc_sys_dentry_operations;
-                                d_add(new, inode);
+                child = d_alloc(dir, &qname);
+                if (child) {
+                        inode = proc_sys_make_inode(dir->d_sb, head, table);
+                        if (!inode) {
+                                dput(child);
+                                return -ENOMEM;
+                        } else {
+                                child->d_op = &proc_sys_dentry_operations;
+                                d_add(child, inode);
                         }
-                        if (child)
-                                dput(new);
-                        else
-                                child = new;
+                } else {
+                        return -ENOMEM;
                 }
         }
-        if (!child || IS_ERR(child) || !child->d_inode)
-                goto end_instantiate;
         inode = child->d_inode;
-        if (inode) {
-                ino  = inode->i_ino;
-                type = inode->i_mode >> 12;
-        }
+        ino  = inode->i_ino;
+        type = inode->i_mode >> 12;
         dput(child);
-end_instantiate:
-        if (!ino)
-                ino= find_inode_number(dir, &qname);
-        if (!ino)
-                ino = 1;
-        return filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
+        return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
+}
+
+static int scan(struct ctl_table_header *head, ctl_table *table,
+                unsigned long *pos, struct file *file,
+                void *dirent, filldir_t filldir)
+{
+
+        for (; table->ctl_name || table->procname; table++, (*pos)++) {
+                int res;
+
+                /* Can't do anything without a proc name */
+                if (!table->procname)
+                        continue;
+
+                if (*pos < file->f_pos)
+                        continue;
+
+                res = proc_sys_fill_cache(file, dirent, filldir, head, table);
+                if (res)
+                        return res;
+
+                file->f_pos = *pos + 1;
+        }
+        return 0;
 }
 
 static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
 {
-        struct dentry *dentry = filp->f_dentry;
+        struct dentry *dentry = filp->f_path.dentry;
         struct inode *inode = dentry->d_inode;
-        struct ctl_table_header *head = NULL;
-        struct ctl_table *table;
+        struct ctl_table_header *head = grab_header(inode);
+        struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+        struct ctl_table_header *h = NULL;
         unsigned long pos;
-        int ret;
+        int ret = -EINVAL;
+
+        if (IS_ERR(head))
+                return PTR_ERR(head);
 
-        ret = -ENOTDIR;
-        if (!S_ISDIR(inode->i_mode))
+        if (table && !table->child) {
+                WARN_ON(1);
                 goto out;
+        }
+
+        table = table ? table->child : head->ctl_table;
 
         ret = 0;
         /* Avoid a switch here: arm builds fail with missing __cmpdi2 */
@@ -311,30 +273,17 @@ static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
         }
         pos = 2;
 
-        /* - Find each instance of the directory
-         * - Read all entries in each instance
-         * - Before returning an entry to user space lookup the entry
-         *   by name and if I find a different entry don't return
-         *   this one because it means it is a buried dup.
-         * For sysctl this should only happen for directory entries.
-         */
-        for (head = sysctl_head_next(NULL); head; head = sysctl_head_next(head)) {
-                table = proc_sys_lookup_table(dentry, head->ctl_table);
+        ret = scan(head, table, &pos, filp, dirent, filldir);
+        if (ret)
+                goto out;
 
-                if (!table)
+        for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
+                if (h->attached_to != table)
                         continue;
-
-                for (; table->ctl_name || table->procname; table++, pos++) {
-                        /* Can't do anything without a proc name */
-                        if (!table->procname)
-                                continue;
-
-                        if (pos < filp->f_pos)
-                                continue;
-
-                        if (proc_sys_fill_cache(filp, dirent, filldir, table) < 0)
-                                goto out;
-                        filp->f_pos = pos + 1;
+                ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
+                if (ret) {
+                        sysctl_head_finish(h);
+                        break;
                 }
         }
         ret = 1;
@@ -343,53 +292,24 @@ out:
         return ret;
 }
 
-static int proc_sys_permission(struct inode *inode, int mask, struct nameidata *nd)
+static int proc_sys_permission(struct inode *inode, int mask)
 {
         /*
          * sysctl entries that are not writeable,
          * are _NOT_ writeable, capabilities or not.
          */
-        struct ctl_table_header *head;
-        struct ctl_table *table;
-        struct dentry *dentry;
-        int mode;
-        int depth;
+        struct ctl_table_header *head = grab_header(inode);
+        struct ctl_table *table = PROC_I(inode)->sysctl_entry;
         int error;
 
-        head = NULL;
-        depth = PROC_I(inode)->fd;
-
-        /* First check the cached permissions, in case we don't have
-         * enough information to lookup the sysctl table entry.
-         */
-        error = -EACCES;
-        mode = inode->i_mode;
-
-        if (current->euid == 0)
-                mode >>= 6;
-        else if (in_group_p(0))
-                mode >>= 3;
-
-        if ((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask)
-                error = 0;
-
-        /* If we can't get a sysctl table entry the permission
-         * checks on the cached mode will have to be enough.
-         */
-        if (!nd || !depth)
-                goto out;
+        if (IS_ERR(head))
+                return PTR_ERR(head);
 
-        dentry = nd->path.dentry;
-        table = do_proc_sys_lookup(dentry->d_parent, &dentry->d_name, &head);
+        if (!table) /* global root - r-xr-xr-x */
+                error = mask & MAY_WRITE ? -EACCES : 0;
+        else /* Use the permissions on the sysctl table entry */
+                error = sysctl_perm(head->root, table, mask);
 
-        /* If the entry does not exist deny permission */
-        error = -EACCES;
-        if (!table)
-                goto out;
-
-        /* Use the permissions on the sysctl table entry */
-        error = sysctl_perm(head->root, table, mask);
-out:
         sysctl_head_finish(head);
         return error;
 }
@@ -409,33 +329,70 @@ static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
         return error;
 }
 
-/* I'm lazy and don't distinguish between files and directories,
- * until access time.
- */
+static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+        struct inode *inode = dentry->d_inode;
+        struct ctl_table_header *head = grab_header(inode);
+        struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+
+        if (IS_ERR(head))
+                return PTR_ERR(head);
+
+        generic_fillattr(inode, stat);
+        if (table)
+                stat->mode = (stat->mode & S_IFMT) | table->mode;
+
+        sysctl_head_finish(head);
+        return 0;
+}
+
 static const struct file_operations proc_sys_file_operations = {
         .read           = proc_sys_read,
         .write          = proc_sys_write,
+};
+
+static const struct file_operations proc_sys_dir_file_operations = {
         .readdir        = proc_sys_readdir,
 };
 
 static const struct inode_operations proc_sys_inode_operations = {
+        .permission     = proc_sys_permission,
+        .setattr        = proc_sys_setattr,
+        .getattr        = proc_sys_getattr,
+};
+
+static const struct inode_operations proc_sys_dir_operations = {
         .lookup         = proc_sys_lookup,
         .permission     = proc_sys_permission,
         .setattr        = proc_sys_setattr,
+        .getattr        = proc_sys_getattr,
 };
 
 static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-        struct ctl_table_header *head;
-        struct ctl_table *table;
-        table = do_proc_sys_lookup(dentry->d_parent, &dentry->d_name, &head);
-        proc_sys_refresh_inode(dentry->d_inode, table);
-        sysctl_head_finish(head);
-        return !!table;
+        return !PROC_I(dentry->d_inode)->sysctl->unregistering;
+}
+
+static int proc_sys_delete(struct dentry *dentry)
+{
+        return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
+}
+
+static int proc_sys_compare(struct dentry *dir, struct qstr *qstr,
+                            struct qstr *name)
+{
+        struct dentry *dentry = container_of(qstr, struct dentry, d_name);
+        if (qstr->len != name->len)
+                return 1;
+        if (memcmp(qstr->name, name->name, name->len))
+                return 1;
+        return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
 }
 
 static struct dentry_operations proc_sys_dentry_operations = {
         .d_revalidate   = proc_sys_revalidate,
+        .d_delete       = proc_sys_delete,
+        .d_compare      = proc_sys_compare,
 };
 
 static struct proc_dir_entry *proc_sys_root;
@@ -443,8 +400,8 @@ static struct proc_dir_entry *proc_sys_root;
 int proc_sys_init(void)
 {
         proc_sys_root = proc_mkdir("sys", NULL);
-        proc_sys_root->proc_iops = &proc_sys_inode_operations;
-        proc_sys_root->proc_fops = &proc_sys_file_operations;
+        proc_sys_root->proc_iops = &proc_sys_dir_operations;
+        proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
         proc_sys_root->nlink = 0;
         return 0;
 }