Merge branch 'akpm' (aka "Andrew's patch-bomb")

Andrew elucidates:
 - First installmeant of MM.  We have a HUGE number of MM patches this
   time.  It's crazy.
 - MAINTAINERS updates
 - backlight updates
 - leds
 - checkpatch updates
 - misc ELF stuff
 - rtc updates
 - reiserfs
 - procfs
 - some misc other bits

* akpm: (124 commits)
  user namespace: make signal.c respect user namespaces
  workqueue: make alloc_workqueue() take printf fmt and args for name
  procfs: add hidepid= and gid= mount options
  procfs: parse mount options
  procfs: introduce the /proc/<pid>/map_files/ directory
  procfs: make proc_get_link to use dentry instead of inode
  signal: add block_sigmask() for adding sigmask to current->blocked
  sparc: make SA_NOMASK a synonym of SA_NODEFER
  reiserfs: don't lock root inode searching
  reiserfs: don't lock journal_init()
  reiserfs: delay reiserfs lock until journal initialization
  reiserfs: delete comments referring to the BKL
  drivers/rtc/interface.c: fix alarm rollover when day or month is out-of-range
  drivers/rtc/rtc-twl.c: add DT support for RTC inside twl4030/twl6030
  drivers/rtc/: remove redundant spi driver bus initialization
  drivers/rtc/rtc-jz4740.c: make jz4740_rtc_driver static
  drivers/rtc/rtc-mc13xxx.c: make mc13xxx_rtc_idtable static
  rtc: convert drivers/rtc/* to use module_platform_driver()
  drivers/rtc/rtc-wm831x.c: convert to devm_kzalloc()
  drivers/rtc/rtc-wm831x.c: remove unused period IRQ handler
  ...

12 files changed, 587 insertions, 83 deletions

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index 79e2ca7973b..e95d1b64082 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -27,6 +27,9 @@ config COMPAT_BINFMT_ELF
 	bool
 	depends on COMPAT && BINFMT_ELF
 
+config ARCH_BINFMT_ELF_RANDOMIZE_PIE
+	bool
+
 config BINFMT_ELF_FDPIC
 	bool "Kernel support for FDPIC ELF binaries"
 	default y
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 21ac5ee4b43..bcb884e2d61 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -794,7 +794,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
 			 * default mmap base, as well as whatever program they
 			 * might try to exec.  This is because the brk will
 			 * follow the loader, and is not movable.  */
-#if defined(CONFIG_X86) || defined(CONFIG_ARM)
+#ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE
 			/* Memory randomization might have been switched off
 			 * in runtime via sysctl.
 			 * If that is the case, retain the original non-zero
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 97fbe939c05..20375e6691c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1081,7 +1081,7 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
 again:
 	for (i = 0; i < num_pages; i++) {
 		pages[i] = find_or_create_page(inode->i_mapping, index + i,
-					       mask);
+					       mask | __GFP_WRITE);
 		if (!pages[i]) {
 			faili = i - 1;
 			err = -ENOMEM;
diff --git a/fs/exec.c b/fs/exec.c
index 3f64b9f26e7..aeb135c7ff5 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -59,6 +59,8 @@
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
+
+#include <trace/events/task.h>
 #include "internal.h"
 
 int core_uses_pid;
@@ -1054,6 +1056,8 @@ void set_task_comm(struct task_struct *tsk, char *buf)
 {
 	task_lock(tsk);
 
+	trace_task_rename(tsk, buf);
+
 	/*
 	 * Threads may access current->comm without holding
 	 * the task lock, so write the string carefully.
diff --git a/fs/inode.c b/fs/inode.c
index 87535753ab0..4fa4f0916af 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -776,6 +776,8 @@ void prune_icache_sb(struct super_block *sb, int nr_to_scan)
 	else
 		__count_vm_events(PGINODESTEAL, reap);
 	spin_unlock(&sb->s_inode_lru_lock);
+	if (current->reclaim_state)
+		current->reclaim_state->reclaimed_slab += reap;
 
 	dispose_list(&freeable);
 }
diff --git a/fs/proc/base.c b/fs/proc/base.c
index a1dddda999f..8173dfd89cb 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -83,9 +83,11 @@
 #include <linux/pid_namespace.h>
 #include <linux/fs_struct.h>
 #include <linux/slab.h>
+#include <linux/flex_array.h>
 #ifdef CONFIG_HARDWALL
 #include <asm/hardwall.h>
 #endif
+#include <trace/events/oom.h>
 #include "internal.h"
 
 /* NOTE:
@@ -133,6 +135,8 @@ struct pid_entry {
 		NULL, &proc_single_file_operations,	\
 		{ .proc_show = show } )
 
+static int proc_fd_permission(struct inode *inode, int mask);
+
 /*
  * Count the number of hardlinks for the pid_entry table, excluding the .
  * and .. links.
@@ -165,9 +169,9 @@ static int get_task_root(struct task_struct *task, struct path *root)
 	return result;
 }
 
-static int proc_cwd_link(struct inode *inode, struct path *path)
+static int proc_cwd_link(struct dentry *dentry, struct path *path)
 {
-	struct task_struct *task = get_proc_task(inode);
+	struct task_struct *task = get_proc_task(dentry->d_inode);
 	int result = -ENOENT;
 
 	if (task) {
@@ -182,9 +186,9 @@ static int proc_cwd_link(struct inode *inode, struct path *path)
 	return result;
 }
 
-static int proc_root_link(struct inode *inode, struct path *path)
+static int proc_root_link(struct dentry *dentry, struct path *path)
 {
-	struct task_struct *task = get_proc_task(inode);
+	struct task_struct *task = get_proc_task(dentry->d_inode);
 	int result = -ENOENT;
 
 	if (task) {
@@ -627,6 +631,50 @@ int proc_setattr(struct dentry *dentry, struct iattr *attr)
 	return 0;
 }
 
+/*
+ * May current process learn task's sched/cmdline info (for hide_pid_min=1)
+ * or euid/egid (for hide_pid_min=2)?
+ */
+static bool has_pid_permissions(struct pid_namespace *pid,
+				 struct task_struct *task,
+				 int hide_pid_min)
+{
+	if (pid->hide_pid < hide_pid_min)
+		return true;
+	if (in_group_p(pid->pid_gid))
+		return true;
+	return ptrace_may_access(task, PTRACE_MODE_READ);
+}
+
+
+static int proc_pid_permission(struct inode *inode, int mask)
+{
+	struct pid_namespace *pid = inode->i_sb->s_fs_info;
+	struct task_struct *task;
+	bool has_perms;
+
+	task = get_proc_task(inode);
+	has_perms = has_pid_permissions(pid, task, 1);
+	put_task_struct(task);
+
+	if (!has_perms) {
+		if (pid->hide_pid == 2) {
+			/*
+			 * Let's make getdents(), stat(), and open()
+			 * consistent with each other.  If a process
+			 * may not stat() a file, it shouldn't be seen
+			 * in procfs at all.
+			 */
+			return -ENOENT;
+		}
+
+		return -EPERM;
+	}
+	return generic_permission(inode, mask);
+}
+
+
+
 static const struct inode_operations proc_def_inode_operations = {
 	.setattr	= proc_setattr,
 };
@@ -1010,6 +1058,7 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
 	else
 		task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
 								-OOM_DISABLE;
+	trace_oom_score_adj_update(task);
 err_sighand:
 	unlock_task_sighand(task, &flags);
 err_task_lock:
@@ -1097,6 +1146,7 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
 	task->signal->oom_score_adj = oom_score_adj;
 	if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
 		task->signal->oom_score_adj_min = oom_score_adj;
+	trace_oom_score_adj_update(task);
 	/*
 	 * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
 	 * always attainable.
@@ -1453,13 +1503,13 @@ static const struct file_operations proc_pid_set_comm_operations = {
 	.release	= single_release,
 };
 
-static int proc_exe_link(struct inode *inode, struct path *exe_path)
+static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
 {
 	struct task_struct *task;
 	struct mm_struct *mm;
 	struct file *exe_file;
 
-	task = get_proc_task(inode);
+	task = get_proc_task(dentry->d_inode);
 	if (!task)
 		return -ENOENT;
 	mm = get_task_mm(task);
@@ -1489,7 +1539,7 @@ static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
 	if (!proc_fd_access_allowed(inode))
 		goto out;
 
-	error = PROC_I(inode)->op.proc_get_link(inode, &nd->path);
+	error = PROC_I(inode)->op.proc_get_link(dentry, &nd->path);
 out:
 	return ERR_PTR(error);
 }
@@ -1528,7 +1578,7 @@ static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int b
 	if (!proc_fd_access_allowed(inode))
 		goto out;
 
-	error = PROC_I(inode)->op.proc_get_link(inode, &path);
+	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
 	if (error)
 		goto out;
 
@@ -1609,6 +1659,7 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 	struct inode *inode = dentry->d_inode;
 	struct task_struct *task;
 	const struct cred *cred;
+	struct pid_namespace *pid = dentry->d_sb->s_fs_info;
 
 	generic_fillattr(inode, stat);
 
@@ -1617,6 +1668,14 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 	stat->gid = 0;
 	task = pid_task(proc_pid(inode), PIDTYPE_PID);
 	if (task) {
+		if (!has_pid_permissions(pid, task, 2)) {
+			rcu_read_unlock();
+			/*
+			 * This doesn't prevent learning whether PID exists,
+			 * it only makes getattr() consistent with readdir().
+			 */
+			return -ENOENT;
+		}
 		if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
 		    task_dumpable(task)) {
 			cred = __task_cred(task);
@@ -1820,9 +1879,9 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info)
 	return -ENOENT;
 }
 
-static int proc_fd_link(struct inode *inode, struct path *path)
+static int proc_fd_link(struct dentry *dentry, struct path *path)
 {
-	return proc_fd_info(inode, path, NULL);
+	return proc_fd_info(dentry->d_inode, path, NULL);
 }
 
 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
@@ -2043,6 +2102,355 @@ static const struct file_operations proc_fd_operations = {
 	.llseek		= default_llseek,
 };
 
+#ifdef CONFIG_CHECKPOINT_RESTORE
+
+/*
+ * dname_to_vma_addr - maps a dentry name into two unsigned longs
+ * which represent vma start and end addresses.
+ */
+static int dname_to_vma_addr(struct dentry *dentry,
+			     unsigned long *start, unsigned long *end)
+{
+	if (sscanf(dentry->d_name.name, "%lx-%lx", start, end) != 2)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int map_files_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	unsigned long vm_start, vm_end;
+	bool exact_vma_exists = false;
+	struct mm_struct *mm = NULL;
+	struct task_struct *task;
+	const struct cred *cred;
+	struct inode *inode;
+	int status = 0;
+
+	if (nd && nd->flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		status = -EACCES;
+		goto out_notask;
+	}
+
+	inode = dentry->d_inode;
+	task = get_proc_task(inode);
+	if (!task)
+		goto out_notask;
+
+	if (!ptrace_may_access(task, PTRACE_MODE_READ))
+		goto out;
+
+	mm = get_task_mm(task);
+	if (!mm)
+		goto out;
+
+	if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
+		down_read(&mm->mmap_sem);
+		exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
+		up_read(&mm->mmap_sem);
+	}
+
+	mmput(mm);
+
+	if (exact_vma_exists) {
+		if (task_dumpable(task)) {
+			rcu_read_lock();
+			cred = __task_cred(task);
+			inode->i_uid = cred->euid;
+			inode->i_gid = cred->egid;
+			rcu_read_unlock();
+		} else {
+			inode->i_uid = 0;
+			inode->i_gid = 0;
+		}
+		security_task_to_inode(task, inode);
+		status = 1;
+	}
+
+out:
+	put_task_struct(task);
+
+out_notask:
+	if (status <= 0)
+		d_drop(dentry);
+
+	return status;
+}
+
+static const struct dentry_operations tid_map_files_dentry_operations = {
+	.d_revalidate	= map_files_d_revalidate,
+	.d_delete	= pid_delete_dentry,
+};
+
+static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
+{
+	unsigned long vm_start, vm_end;
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	int rc;
+
+	rc = -ENOENT;
+	task = get_proc_task(dentry->d_inode);
+	if (!task)
+		goto out;
+
+	mm = get_task_mm(task);
+	put_task_struct(task);
+	if (!mm)
+		goto out;
+
+	rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
+	if (rc)
+		goto out_mmput;
+
+	down_read(&mm->mmap_sem);
+	vma = find_exact_vma(mm, vm_start, vm_end);
+	if (vma && vma->vm_file) {
+		*path = vma->vm_file->f_path;
+		path_get(path);
+		rc = 0;
+	}
+	up_read(&mm->mmap_sem);
+
+out_mmput:
+	mmput(mm);
+out:
+	return rc;
+}
+
+struct map_files_info {
+	struct file	*file;
+	unsigned long	len;
+	unsigned char	name[4*sizeof(long)+2]; /* max: %lx-%lx\0 */
+};
+
+static struct dentry *
+proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
+			   struct task_struct *task, const void *ptr)
+{
+	const struct file *file = ptr;
+	struct proc_inode *ei;
+	struct inode *inode;
+
+	if (!file)
+		return ERR_PTR(-ENOENT);
+
+	inode = proc_pid_make_inode(dir->i_sb, task);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	ei->op.proc_get_link = proc_map_files_get_link;
+
+	inode->i_op = &proc_pid_link_inode_operations;
+	inode->i_size = 64;
+	inode->i_mode = S_IFLNK;
+
+	if (file->f_mode & FMODE_READ)
+		inode->i_mode |= S_IRUSR;
+	if (file->f_mode & FMODE_WRITE)
+		inode->i_mode |= S_IWUSR;
+
+	d_set_d_op(dentry, &tid_map_files_dentry_operations);
+	d_add(dentry, inode);
+
+	return NULL;
+}
+
+static struct dentry *proc_map_files_lookup(struct inode *dir,
+		struct dentry *dentry, struct nameidata *nd)
+{
+	unsigned long vm_start, vm_end;
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct dentry *result;
+	struct mm_struct *mm;
+
+	result = ERR_PTR(-EACCES);
+	if (!capable(CAP_SYS_ADMIN))
+		goto out;
+
+	result = ERR_PTR(-ENOENT);
+	task = get_proc_task(dir);
+	if (!task)
+		goto out;
+
+	result = ERR_PTR(-EACCES);
+	if (lock_trace(task))
+		goto out_put_task;
+
+	result = ERR_PTR(-ENOENT);
+	if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
+		goto out_unlock;
+
+	mm = get_task_mm(task);
+	if (!mm)
+		goto out_unlock;
+
+	down_read(&mm->mmap_sem);
+	vma = find_exact_vma(mm, vm_start, vm_end);
+	if (!vma)
+		goto out_no_vma;
+
+	result = proc_map_files_instantiate(dir, dentry, task, vma->vm_file);
+
+out_no_vma:
+	up_read(&mm->mmap_sem);
+	mmput(mm);
+out_unlock:
+	unlock_trace(task);
+out_put_task:
+	put_task_struct(task);
+out:
+	return result;
+}
+
+static const struct inode_operations proc_map_files_inode_operations = {
+	.lookup		= proc_map_files_lookup,
+	.permission	= proc_fd_permission,
+	.setattr	= proc_setattr,
+};
+
+static int
+proc_map_files_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	struct inode *inode = dentry->d_inode;
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	ino_t ino;
+	int ret;
+
+	ret = -EACCES;
+	if (!capable(CAP_SYS_ADMIN))
+		goto out;
+
+	ret = -ENOENT;
+	task = get_proc_task(inode);
+	if (!task)
+		goto out;
+
+	ret = -EACCES;
+	if (lock_trace(task))
+		goto out_put_task;
+
+	ret = 0;
+	switch (filp->f_pos) {
+	case 0:
+		ino = inode->i_ino;
+		if (filldir(dirent, ".", 1, 0, ino, DT_DIR) < 0)
+			goto out_unlock;
+		filp->f_pos++;
+	case 1:
+		ino = parent_ino(dentry);
+		if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
+			goto out_unlock;
+		filp->f_pos++;
+	default:
+	{
+		unsigned long nr_files, pos, i;
+		struct flex_array *fa = NULL;
+		struct map_files_info info;
+		struct map_files_info *p;
+
+		mm = get_task_mm(task);
+		if (!mm)
+			goto out_unlock;
+		down_read(&mm->mmap_sem);
+
+		nr_files = 0;
+
+		/*
+		 * We need two passes here:
+		 *
+		 *  1) Collect vmas of mapped files with mmap_sem taken
+		 *  2) Release mmap_sem and instantiate entries
+		 *
+		 * otherwise we get lockdep complained, since filldir()
+		 * routine might require mmap_sem taken in might_fault().
+		 */
+
+		for (vma = mm->mmap, pos = 2; vma; vma = vma->vm_next) {
+			if (vma->vm_file && ++pos > filp->f_pos)
+				nr_files++;
+		}
+
+		if (nr_files) {
+			fa = flex_array_alloc(sizeof(info), nr_files,
+						GFP_KERNEL);
+			if (!fa || flex_array_prealloc(fa, 0, nr_files,
+							GFP_KERNEL)) {
+				ret = -ENOMEM;
+				if (fa)
+					flex_array_free(fa);
+				up_read(&mm->mmap_sem);
+				mmput(mm);
+				goto out_unlock;
+			}
+			for (i = 0, vma = mm->mmap, pos = 2; vma;
+					vma = vma->vm_next) {
+				if (!vma->vm_file)
+					continue;
+				if (++pos <= filp->f_pos)
+					continue;
+
+				get_file(vma->vm_file);
+				info.file = vma->vm_file;
+				info.len = snprintf(info.name,
+						sizeof(info.name), "%lx-%lx",
+						vma->vm_start, vma->vm_end);
+				if (flex_array_put(fa, i++, &info, GFP_KERNEL))
+					BUG();
+			}
+		}
+		up_read(&mm->mmap_sem);
+
+		for (i = 0; i < nr_files; i++) {
+			p = flex_array_get(fa, i);
+			ret = proc_fill_cache(filp, dirent, filldir,
+					      p->name, p->len,
+					      proc_map_files_instantiate,
+					      task, p->file);
+			if (ret)
+				break;
+			filp->f_pos++;
+			fput(p->file);
+		}
+		for (; i < nr_files; i++) {
+			/*
+			 * In case of error don't forget
+			 * to put rest of file refs.
+			 */
+			p = flex_array_get(fa, i);
+			fput(p->file);
+		}
+		if (fa)
+			flex_array_free(fa);
+		mmput(mm);
+	}
+	}
+
+out_unlock:
+	unlock_trace(task);
+out_put_task:
+	put_task_struct(task);
+out:
+	return ret;
+}
+
+static const struct file_operations proc_map_files_operations = {
+	.read		= generic_read_dir,
+	.readdir	= proc_map_files_readdir,
+	.llseek		= default_llseek,
+};
+
+#endif /* CONFIG_CHECKPOINT_RESTORE */
+
 /*
  * /proc/pid/fd needs a special permission handler so that a process can still
  * access /proc/self/fd after it has executed a setuid().
@@ -2658,6 +3066,9 @@ static const struct inode_operations proc_task_inode_operations;
 static const struct pid_entry tgid_base_stuff[] = {
 	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
 	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
+#endif
 	DIR("fdinfo",     S_IRUSR|S_IXUSR, proc_fdinfo_inode_operations, proc_fdinfo_operations),
 	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
 #ifdef CONFIG_NET
@@ -2761,6 +3172,7 @@ static const struct inode_operations proc_tgid_base_inode_operations = {
 	.lookup		= proc_tgid_base_lookup,
 	.getattr	= pid_getattr,
 	.setattr	= proc_setattr,
+	.permission	= proc_pid_permission,
 };
 
 static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
@@ -2964,6 +3376,12 @@ static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldi
 				proc_pid_instantiate, iter.task, NULL);
 }
 
+static int fake_filldir(void *buf, const char *name, int namelen,
+			loff_t offset, u64 ino, unsigned d_type)
+{
+	return 0;
+}
+
 /* for the /proc/ directory itself, after non-process stuff has been done */
 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
@@ -2971,6 +3389,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
 	struct task_struct *reaper;
 	struct tgid_iter iter;
 	struct pid_namespace *ns;
+	filldir_t __filldir;
 
 	if (filp->f_pos >= PID_MAX_LIMIT + TGID_OFFSET)
 		goto out_no_task;
@@ -2992,8 +3411,13 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
 	for (iter = next_tgid(ns, iter);
 	     iter.task;
 	     iter.tgid += 1, iter = next_tgid(ns, iter)) {
+		if (has_pid_permissions(ns, iter.task, 2))
+			__filldir = filldir;
+		else
+			__filldir = fake_filldir;
+
 		filp->f_pos = iter.tgid + TGID_OFFSET;
-		if (proc_pid_fill_cache(filp, dirent, filldir, iter) < 0) {
+		if (proc_pid_fill_cache(filp, dirent, __filldir, iter) < 0) {
 			put_task_struct(iter.task);
 			goto out;
 		}
@@ -3328,6 +3752,7 @@ static const struct inode_operations proc_task_inode_operations = {
 	.lookup		= proc_task_lookup,
 	.getattr	= proc_task_getattr,
 	.setattr	= proc_setattr,
+	.permission	= proc_pid_permission,
 };
 
 static const struct file_operations proc_task_operations = {
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 51a176622b8..84fd3235a59 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -7,6 +7,7 @@
 #include <linux/time.h>
 #include <linux/proc_fs.h>
 #include <linux/kernel.h>
+#include <linux/pid_namespace.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/stat.h>
@@ -17,7 +18,9 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/sysctl.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
+#include <linux/mount.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -101,12 +104,27 @@ void __init proc_init_inodecache(void)
 					     init_once);
 }
 
+static int proc_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct pid_namespace *pid = sb->s_fs_info;
+
+	if (pid->pid_gid)
+		seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid);
+	if (pid->hide_pid != 0)
+		seq_printf(seq, ",hidepid=%u", pid->hide_pid);
+
+	return 0;
+}
+
 static const struct super_operations proc_sops = {
 	.alloc_inode	= proc_alloc_inode,
 	.destroy_inode	= proc_destroy_inode,
 	.drop_inode	= generic_delete_inode,
 	.evict_inode	= proc_evict_inode,
 	.statfs		= simple_statfs,
+	.remount_fs	= proc_remount,
+	.show_options	= proc_show_options,
 };
 
 static void __pde_users_dec(struct proc_dir_entry *pde)
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 7838e5cfec1..292577531ad 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -117,6 +117,7 @@ void pde_put(struct proc_dir_entry *pde);
 
 int proc_fill_super(struct super_block *);
 struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
+int proc_remount(struct super_block *sb, int *flags, char *data);
 
 /*
  * These are generic /proc routines that use the internal
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 03102d97818..46a15d8a29c 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -18,6 +18,7 @@
 #include <linux/bitops.h>
 #include <linux/mount.h>
 #include <linux/pid_namespace.h>
+#include <linux/parser.h>
 
 #include "internal.h"
 
@@ -36,6 +37,63 @@ static int proc_set_super(struct super_block *sb, void *data)
 	return err;
 }
 
+enum {
+	Opt_gid, Opt_hidepid, Opt_err,
+};
+
+static const match_table_t tokens = {
+	{Opt_hidepid, "hidepid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_err, NULL},
+};
+
+static int proc_parse_options(char *options, struct pid_namespace *pid)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		args[0].to = args[0].from = 0;
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+				return 0;
+			pid->pid_gid = option;
+			break;
+		case Opt_hidepid:
+			if (match_int(&args[0], &option))
+				return 0;
+			if (option < 0 || option > 2) {
+				pr_err("proc: hidepid value must be between 0 and 2.\n");
+				return 0;
+			}
+			pid->hide_pid = option;
+			break;
+		default:
+			pr_err("proc: unrecognized mount option \"%s\" "
+			       "or missing value\n", p);
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
+int proc_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct pid_namespace *pid = sb->s_fs_info;
+	return !proc_parse_options(data, pid);
+}
+
 static struct dentry *proc_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
@@ -43,11 +101,15 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 	struct super_block *sb;
 	struct pid_namespace *ns;
 	struct proc_inode *ei;
+	char *options;
 
-	if (flags & MS_KERNMOUNT)
+	if (flags & MS_KERNMOUNT) {
 		ns = (struct pid_namespace *)data;
-	else
+		options = NULL;
+	} else {
 		ns = current->nsproxy->pid_ns;
+		options = data;
+	}
 
 	sb = sget(fs_type, proc_test_super, proc_set_super, ns);
 	if (IS_ERR(sb))
@@ -55,6 +117,10 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
 
 	if (!sb->s_root) {
 		sb->s_flags = flags;
+		if (!proc_parse_options(options, ns)) {
+			deactivate_locked_super(sb);
+			return ERR_PTR(-EINVAL);
+		}
 		err = proc_fill_super(sb);
 		if (err) {
 			deactivate_locked_super(sb);
diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c
index a945cd26522..70de42f09f1 100644
--- a/fs/reiserfs/bitmap.c
+++ b/fs/reiserfs/bitmap.c
@@ -1364,10 +1364,7 @@ int reiserfs_init_bitmap_cache(struct super_block *sb)
 	struct reiserfs_bitmap_info *bitmap;
 	unsigned int bmap_nr = reiserfs_bmap_count(sb);
 
-	/* Avoid lock recursion in fault case */
-	reiserfs_write_unlock(sb);
 	bitmap = vmalloc(sizeof(*bitmap) * bmap_nr);
-	reiserfs_write_lock(sb);
 	if (bitmap == NULL)
 		return -ENOMEM;
 
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index eb711060a6f..c3cf54fd4de 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2678,16 +2678,10 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 	char b[BDEVNAME_SIZE];
 	int ret;
 
-	/*
-	 * Unlock here to avoid various RECLAIM-FS-ON <-> IN-RECLAIM-FS
-	 * dependency inversion warnings.
-	 */
-	reiserfs_write_unlock(sb);
 	journal = SB_JOURNAL(sb) = vzalloc(sizeof(struct reiserfs_journal));
 	if (!journal) {
 		reiserfs_warning(sb, "journal-1256",
 				 "unable to get memory for journal structure");
-		reiserfs_write_lock(sb);
 		return 1;
 	}
 	INIT_LIST_HEAD(&journal->j_bitmap_nodes);
@@ -2695,10 +2689,8 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 	INIT_LIST_HEAD(&journal->j_working_list);
 	INIT_LIST_HEAD(&journal->j_journal_list);
 	journal->j_persistent_trans = 0;
-	ret = reiserfs_allocate_list_bitmaps(sb, journal->j_list_bitmap,
-					   reiserfs_bmap_count(sb));
-	reiserfs_write_lock(sb);
-	if (ret)
+	if (reiserfs_allocate_list_bitmaps(sb, journal->j_list_bitmap,
+					   reiserfs_bmap_count(sb)))
 		goto free_and_return;
 
 	allocate_bitmap_nodes(sb);
@@ -2727,27 +2719,11 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 		goto free_and_return;
 	}
 
-	/*
-	 * We need to unlock here to avoid creating the following
-	 * dependency:
-	 * reiserfs_lock -> sysfs_mutex
-	 * Because the reiserfs mmap path creates the following dependency:
-	 * mm->mmap -> reiserfs_lock, hence we have
-	 * mm->mmap -> reiserfs_lock ->sysfs_mutex
-	 * This would ends up in a circular dependency with sysfs readdir path
-	 * which does sysfs_mutex -> mm->mmap_sem
-	 * This is fine because the reiserfs lock is useless in mount path,
-	 * at least until we call journal_begin. We keep it for paranoid
-	 * reasons.
-	 */
-	reiserfs_write_unlock(sb);
 	if (journal_init_dev(sb, journal, j_dev_name) != 0) {
-		reiserfs_write_lock(sb);
 		reiserfs_warning(sb, "sh-462",
 				 "unable to initialize jornal device");
 		goto free_and_return;
 	}
-	reiserfs_write_lock(sb);
 
 	rs = SB_DISK_SUPER_BLOCK(sb);
 
@@ -2829,9 +2805,7 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 	journal->j_mount_id = 10;
 	journal->j_state = 0;
 	atomic_set(&(journal->j_jlock), 0);
-	reiserfs_write_unlock(sb);
 	journal->j_cnode_free_list = allocate_cnodes(num_cnodes);
-	reiserfs_write_lock(sb);
 	journal->j_cnode_free_orig = journal->j_cnode_free_list;
 	journal->j_cnode_free = journal->j_cnode_free_list ? num_cnodes : 0;
 	journal->j_cnode_used = 0;
@@ -2848,24 +2822,37 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
 
 	init_journal_hash(sb);
 	jl = journal->j_current_jl;
+
+	/*
+	 * get_list_bitmap() may call flush_commit_list() which
+	 * requires the lock. Calling flush_commit_list() shouldn't happen
+	 * this early but I like to be paranoid.
+	 */
+	reiserfs_write_lock(sb);
 	jl->j_list_bitmap = get_list_bitmap(sb, jl);
+	reiserfs_write_unlock(sb);
 	if (!jl->j_list_bitmap) {
 		reiserfs_warning(sb, "journal-2005",
 				 "get_list_bitmap failed for journal list 0");
 		goto free_and_return;
 	}
-	if (journal_read(sb) < 0) {
+
+	/*
+	 * Journal_read needs to be inspected in order to push down
+	 * the lock further inside (or even remove it).
+	 */
+	reiserfs_write_lock(sb);
+	ret = journal_read(sb);
+	reiserfs_write_unlock(sb);
+	if (ret < 0) {
 		reiserfs_warning(sb, "reiserfs-2006",
 				 "Replay Failure, unable to mount");
 		goto free_and_return;
 	}
 
 	reiserfs_mounted_fs_count++;
-	if (reiserfs_mounted_fs_count <= 1) {
-		reiserfs_write_unlock(sb);
+	if (reiserfs_mounted_fs_count <= 1)
 		commit_wq = alloc_workqueue("reiserfs", WQ_MEM_RECLAIM, 0);
-		reiserfs_write_lock(sb);
-	}
 
 	INIT_DELAYED_WORK(&journal->j_work, flush_async_commits);
 	journal->j_work_sb = sb;
@@ -2896,14 +2883,13 @@ int journal_transaction_should_end(struct reiserfs_transaction_handle *th,
 	    journal->j_cnode_free < (journal->j_trans_max * 3)) {
 		return 1;
 	}
-	/* protected by the BKL here */
+
 	journal->j_len_alloc += new_alloc;
 	th->t_blocks_allocated += new_alloc ;
 	return 0;
 }
 
-/* this must be called inside a transaction, and requires the
-** kernel_lock to be held
+/* this must be called inside a transaction
 */
 void reiserfs_block_writes(struct reiserfs_transaction_handle *th)
 {
@@ -2914,8 +2900,7 @@ void reiserfs_block_writes(struct reiserfs_transaction_handle *th)
 	return;
 }
 
-/* this must be called without a transaction started, and does not
-** require BKL
+/* this must be called without a transaction started
 */
 void reiserfs_allow_writes(struct super_block *s)
 {
@@ -2924,8 +2909,7 @@ void reiserfs_allow_writes(struct super_block *s)
 	wake_up(&journal->j_join_wait);
 }
 
-/* this must be called without a transaction started, and does not
-** require BKL
+/* this must be called without a transaction started
 */
 void reiserfs_wait_on_write_block(struct super_block *s)
 {
diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 1d42e707d5f..e12d8b97cd4 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -1519,9 +1519,7 @@ static int read_super_block(struct super_block *s, int offset)
 static int reread_meta_blocks(struct super_block *s)
 {
 	ll_rw_block(READ, 1, &(SB_BUFFER_WITH_SB(s)));
-	reiserfs_write_unlock(s);
 	wait_on_buffer(SB_BUFFER_WITH_SB(s));
-	reiserfs_write_lock(s);
 	if (!buffer_uptodate(SB_BUFFER_WITH_SB(s))) {
 		reiserfs_warning(s, "reiserfs-2504", "error reading the super");
 		return 1;
@@ -1746,22 +1744,11 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	mutex_init(&REISERFS_SB(s)->lock);
 	REISERFS_SB(s)->lock_depth = -1;
 
-	/*
-	 * This function is called with the bkl, which also was the old
-	 * locking used here.
-	 * do_journal_begin() will soon check if we hold the lock (ie: was the
-	 * bkl). This is likely because do_journal_begin() has several another
-	 * callers because at this time, it doesn't seem to be necessary to
-	 * protect against anything.
-	 * Anyway, let's be conservative and lock for now.
-	 */
-	reiserfs_write_lock(s);
-
 	jdev_name = NULL;
 	if (reiserfs_parse_options
 	    (s, (char *)data, &(sbi->s_mount_opt), &blocks, &jdev_name,
 	     &commit_max_age, qf_names, &qfmt) == 0) {
-		goto error;
+		goto error_unlocked;
 	}
 	if (jdev_name && jdev_name[0]) {
 		REISERFS_SB(s)->s_jdev = kstrdup(jdev_name, GFP_KERNEL);
@@ -1777,7 +1764,7 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 
 	if (blocks) {
 		SWARN(silent, s, "jmacd-7", "resize option for remount only");
-		goto error;
+		goto error_unlocked;
 	}
 
 	/* try old format (undistributed bitmap, super block in 8-th 1k block of a device) */
@@ -1787,7 +1774,7 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	else if (read_super_block(s, REISERFS_DISK_OFFSET_IN_BYTES)) {
 		SWARN(silent, s, "sh-2021", "can not find reiserfs on %s",
 		      reiserfs_bdevname(s));
-		goto error;
+		goto error_unlocked;
 	}
 
 	rs = SB_DISK_SUPER_BLOCK(s);
@@ -1803,7 +1790,7 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 		      "or increase size of your LVM partition");
 		SWARN(silent, s, "", "Or may be you forgot to "
 		      "reboot after fdisk when it told you to");
-		goto error;
+		goto error_unlocked;
 	}
 
 	sbi->s_mount_state = SB_REISERFS_STATE(s);
@@ -1811,8 +1798,9 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 
 	if ((errval = reiserfs_init_bitmap_cache(s))) {
 		SWARN(silent, s, "jmacd-8", "unable to read bitmap");
-		goto error;
+		goto error_unlocked;
 	}
+
 	errval = -EINVAL;
 #ifdef CONFIG_REISERFS_CHECK
 	SWARN(silent, s, "", "CONFIG_REISERFS_CHECK is set ON");
@@ -1835,24 +1823,26 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	if (reiserfs_barrier_flush(s)) {
 		printk("reiserfs: using flush barriers\n");
 	}
+
 	// set_device_ro(s->s_dev, 1) ;
 	if (journal_init(s, jdev_name, old_format, commit_max_age)) {
 		SWARN(silent, s, "sh-2022",
 		      "unable to initialize journal space");
-		goto error;
+		goto error_unlocked;
 	} else {
 		jinit_done = 1;	/* once this is set, journal_release must be called
 				 ** if we error out of the mount
 				 */
 	}
+
 	if (reread_meta_blocks(s)) {
 		SWARN(silent, s, "jmacd-9",
 		      "unable to reread meta blocks after journal init");
-		goto error;
+		goto error_unlocked;
 	}
 
 	if (replay_only(s))
-		goto error;
+		goto error_unlocked;
 
 	if (bdev_read_only(s->s_bdev) && !(s->s_flags & MS_RDONLY)) {
 		SWARN(silent, s, "clm-7000",
@@ -1866,9 +1856,19 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 			 reiserfs_init_locked_inode, (void *)(&args));
 	if (!root_inode) {
 		SWARN(silent, s, "jmacd-10", "get root inode failed");
-		goto error;
+		goto error_unlocked;
 	}
 
+	/*
+	 * This path assumed to be called with the BKL in the old times.
+	 * Now we have inherited the big reiserfs lock from it and many
+	 * reiserfs helpers called in the mount path and elsewhere require
+	 * this lock to be held even if it's not always necessary. Let's be
+	 * conservative and hold it early. The window can be reduced after
+	 * careful review of the code.
+	 */
+	reiserfs_write_lock(s);
+
 	if (root_inode->i_state & I_NEW) {
 		reiserfs_read_locked_inode(root_inode, &args);
 		unlock_new_inode(root_inode);
@@ -1995,12 +1995,16 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 	return (0);
 
 error:
-	if (jinit_done) {	/* kill the commit thread, free journal ram */
+	reiserfs_write_unlock(s);
+
+error_unlocked:
+	/* kill the commit thread, free journal ram */
+	if (jinit_done) {
+		reiserfs_write_lock(s);
 		journal_release_error(NULL, s);
+		reiserfs_write_unlock(s);
 	}
 
-	reiserfs_write_unlock(s);
-
 	reiserfs_free_bitmap_cache(s);
 	if (SB_BUFFER_WITH_SB(s))
 		brelse(SB_BUFFER_WITH_SB(s));