Merge branch 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin

* 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits)
  fs: scale mntget/mntput
  fs: rename vfsmount counter helpers
  fs: implement faster dentry memcmp
  fs: prefetch inode data in dcache lookup
  fs: improve scalability of pseudo filesystems
  fs: dcache per-inode inode alias locking
  fs: dcache per-bucket dcache hash locking
  bit_spinlock: add required includes
  kernel: add bl_list
  xfs: provide simple rcu-walk ACL implementation
  btrfs: provide simple rcu-walk ACL implementation
  ext2,3,4: provide simple rcu-walk ACL implementation
  fs: provide simple rcu-walk generic_check_acl implementation
  fs: provide rcu-walk aware permission i_ops
  fs: rcu-walk aware d_revalidate method
  fs: cache optimise dentry and inode for rcu-walk
  fs: dcache reduce branches in lookup path
  fs: dcache remove d_mounted
  fs: fs_struct use seqlock
  fs: rcu-walk for path lookup
  ...

4 files changed, 68 insertions, 29 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 08cba2c..b20962c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1795,10 +1795,16 @@ static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat
  */
 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-	struct inode *inode = dentry->d_inode;
-	struct task_struct *task = get_proc_task(inode);
+	struct inode *inode;
+	struct task_struct *task;
 	const struct cred *cred;
 
+	if (nd && nd->flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = dentry->d_inode;
+	task = get_proc_task(inode);
+
 	if (task) {
 		if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) ||
 		    task_dumpable(task)) {
@@ -1820,7 +1826,7 @@ static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
 	return 0;
 }
 
-static int pid_delete_dentry(struct dentry * dentry)
+static int pid_delete_dentry(const struct dentry * dentry)
 {
 	/* Is the task we represent dead?
 	 * If so, then don't put the dentry on the lru list,
@@ -1964,12 +1970,19 @@ static int proc_fd_link(struct inode *inode, struct path *path)
 
 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-	struct inode *inode = dentry->d_inode;
-	struct task_struct *task = get_proc_task(inode);
-	int fd = proc_fd(inode);
+	struct inode *inode;
+	struct task_struct *task;
+	int fd;
 	struct files_struct *files;
 	const struct cred *cred;
 
+	if (nd && nd->flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = dentry->d_inode;
+	task = get_proc_task(inode);
+	fd = proc_fd(inode);
+
 	if (task) {
 		files = get_files_struct(task);
 		if (files) {
@@ -2045,7 +2058,7 @@ static struct dentry *proc_fd_instantiate(struct inode *dir,
 	inode->i_op = &proc_pid_link_inode_operations;
 	inode->i_size = 64;
 	ei->op.proc_get_link = proc_fd_link;
-	dentry->d_op = &tid_fd_dentry_operations;
+	d_set_d_op(dentry, &tid_fd_dentry_operations);
 	d_add(dentry, inode);
 	/* Close the race of the process dying before we return the dentry */
 	if (tid_fd_revalidate(dentry, NULL))
@@ -2177,11 +2190,13 @@ 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)
+static int proc_fd_permission(struct inode *inode, int mask, unsigned int flags)
 {
 	int rv;
 
-	rv = generic_permission(inode, mask, NULL);
+	if (flags & IPERM_FLAG_RCU)
+		return -ECHILD;
+	rv = generic_permission(inode, mask, flags, NULL);
 	if (rv == 0)
 		return 0;
 	if (task_pid(current) == proc_pid(inode))
@@ -2213,7 +2228,7 @@ static struct dentry *proc_fdinfo_instantiate(struct inode *dir,
 	ei->fd = fd;
 	inode->i_mode = S_IFREG | S_IRUSR;
 	inode->i_fop = &proc_fdinfo_file_operations;
-	dentry->d_op = &tid_fd_dentry_operations;
+	d_set_d_op(dentry, &tid_fd_dentry_operations);
 	d_add(dentry, inode);
 	/* Close the race of the process dying before we return the dentry */
 	if (tid_fd_revalidate(dentry, NULL))
@@ -2272,7 +2287,7 @@ static struct dentry *proc_pident_instantiate(struct inode *dir,
 	if (p->fop)
 		inode->i_fop = p->fop;
 	ei->op = p->op;
-	dentry->d_op = &pid_dentry_operations;
+	d_set_d_op(dentry, &pid_dentry_operations);
 	d_add(dentry, inode);
 	/* Close the race of the process dying before we return the dentry */
 	if (pid_revalidate(dentry, NULL))
@@ -2639,8 +2654,14 @@ static const struct pid_entry proc_base_stuff[] = {
  */
 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-	struct inode *inode = dentry->d_inode;
-	struct task_struct *task = get_proc_task(inode);
+	struct inode *inode;
+	struct task_struct *task;
+
+	if (nd->flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = dentry->d_inode;
+	task = get_proc_task(inode);
 	if (task) {
 		put_task_struct(task);
 		return 1;
@@ -2691,7 +2712,7 @@ static struct dentry *proc_base_instantiate(struct inode *dir,
 	if (p->fop)
 		inode->i_fop = p->fop;
 	ei->op = p->op;
-	dentry->d_op = &proc_base_dentry_operations;
+	d_set_d_op(dentry, &proc_base_dentry_operations);
 	d_add(dentry, inode);
 	error = NULL;
 out:
@@ -3005,7 +3026,7 @@ static struct dentry *proc_pid_instantiate(struct inode *dir,
 	inode->i_nlink = 2 + pid_entry_count_dirs(tgid_base_stuff,
 		ARRAY_SIZE(tgid_base_stuff));
 
-	dentry->d_op = &pid_dentry_operations;
+	d_set_d_op(dentry, &pid_dentry_operations);
 
 	d_add(dentry, inode);
 	/* Close the race of the process dying before we return the dentry */
@@ -3248,7 +3269,7 @@ static struct dentry *proc_task_instantiate(struct inode *dir,
 	inode->i_nlink = 2 + pid_entry_count_dirs(tid_base_stuff,
 		ARRAY_SIZE(tid_base_stuff));
 
-	dentry->d_op = &pid_dentry_operations;
+	d_set_d_op(dentry, &pid_dentry_operations);
 
 	d_add(dentry, inode);
 	/* Close the race of the process dying before we return the dentry */
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index dd29f03..f766be2 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -400,7 +400,7 @@ static const struct inode_operations proc_link_inode_operations = {
  * smarter: we could keep a "volatile" flag in the 
  * inode to indicate which ones to keep.
  */
-static int proc_delete_dentry(struct dentry * dentry)
+static int proc_delete_dentry(const struct dentry * dentry)
 {
 	return 1;
 }
@@ -439,7 +439,7 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 out_unlock:
 
 	if (inode) {
-		dentry->d_op = &proc_dentry_operations;
+		d_set_d_op(dentry, &proc_dentry_operations);
 		d_add(dentry, inode);
 		return NULL;
 	}
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 3ddb606..6bcb926 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -65,11 +65,18 @@ static struct inode *proc_alloc_inode(struct super_block *sb)
 	return inode;
 }
 
-static void proc_destroy_inode(struct inode *inode)
+static void proc_i_callback(struct rcu_head *head)
 {
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	INIT_LIST_HEAD(&inode->i_dentry);
 	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
 }
 
+static void proc_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, proc_i_callback);
+}
+
 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 b652cb0..09a1f92 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -5,6 +5,7 @@
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
 #include <linux/security.h>
+#include <linux/namei.h>
 #include "internal.h"
 
 static const struct dentry_operations proc_sys_dentry_operations;
@@ -120,7 +121,7 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
 		goto out;
 
 	err = NULL;
-	dentry->d_op = &proc_sys_dentry_operations;
+	d_set_d_op(dentry, &proc_sys_dentry_operations);
 	d_add(dentry, inode);
 
 out:
@@ -201,7 +202,7 @@ static int proc_sys_fill_cache(struct file *filp, void *dirent,
 				dput(child);
 				return -ENOMEM;
 			} else {
-				child->d_op = &proc_sys_dentry_operations;
+				d_set_d_op(child, &proc_sys_dentry_operations);
 				d_add(child, inode);
 			}
 		} else {
@@ -294,7 +295,7 @@ out:
 	return ret;
 }
 
-static int proc_sys_permission(struct inode *inode, int mask)
+static int proc_sys_permission(struct inode *inode, int mask,unsigned int flags)
 {
 	/*
 	 * sysctl entries that are not writeable,
@@ -304,6 +305,9 @@ static int proc_sys_permission(struct inode *inode, int mask)
 	struct ctl_table *table;
 	int error;
 
+	if (flags & IPERM_FLAG_RCU)
+		return -ECHILD;
+
 	/* Executable files are not allowed under /proc/sys/ */
 	if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
 		return -EACCES;
@@ -389,23 +393,30 @@ static const struct inode_operations proc_sys_dir_operations = {
 
 static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
+	if (nd->flags & LOOKUP_RCU)
+		return -ECHILD;
 	return !PROC_I(dentry->d_inode)->sysctl->unregistering;
 }
 
-static int proc_sys_delete(struct dentry *dentry)
+static int proc_sys_delete(const 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)
+static int proc_sys_compare(const struct dentry *parent,
+		const struct inode *pinode,
+		const struct dentry *dentry, const struct inode *inode,
+		unsigned int len, const char *str, const struct qstr *name)
 {
-	struct dentry *dentry = container_of(qstr, struct dentry, d_name);
-	if (qstr->len != name->len)
+	/* Although proc doesn't have negative dentries, rcu-walk means
+	 * that inode here can be NULL */
+	if (!inode)
+		return 0;
+	if (name->len != len)
 		return 1;
-	if (memcmp(qstr->name, name->name, name->len))
+	if (memcmp(name->name, str, len))
 		return 1;
-	return !sysctl_is_seen(PROC_I(dentry->d_inode)->sysctl);
+	return !sysctl_is_seen(PROC_I(inode)->sysctl);
 }
 
 static const struct dentry_operations proc_sys_dentry_operations = {