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authorNick Piggin2011-01-07 17:49:57 +1100
committerNick Piggin2011-01-07 17:50:29 +1100
commit34286d6662308d82aed891852d04c7c3a2649b16 (patch)
treec4b7311404d302e7cb94df7a4690298e1059910a /fs/proc
parent44a7d7a878c9cbb74f236ea755b25b6b2e26a9a9 (diff)
fs: rcu-walk aware d_revalidate method
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/base.c33
-rw-r--r--fs/proc/proc_sysctl.c3
2 files changed, 29 insertions, 7 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 85f0a80912aa..dc5b2fcadc3b 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1719,10 +1719,16 @@ 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)) {
@@ -1888,12 +1894,19 @@ 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) {
@@ -2563,8 +2576,14 @@ 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;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 35efd85a4d32..c9097f43b425 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;
@@ -389,6 +390,8 @@ 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;
}