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Subject[PATCH 77/79] namei: move unlazying on symlinks towards get_link() call sites
Date
From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 45 +++++++++++++++++++++++++++++++++------------
1 file changed, 33 insertions(+), 12 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 98e932c..eb3f7d9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -538,10 +538,18 @@ static void restore_nameidata(struct nameidata *old)

static int __nd_alloc_stack(struct nameidata *nd)
{
- struct saved *p = kmalloc(MAXSYMLINKS * sizeof(struct saved),
- GFP_KERNEL);
- if (unlikely(!p))
- return -ENOMEM;
+ struct saved *p;
+ if (nd->flags & LOOKUP_RCU) {
+ p = kmalloc(MAXSYMLINKS * sizeof(struct saved),
+ GFP_ATOMIC);
+ if (unlikely(!p))
+ return -ECHILD;
+ } else {
+ p = kmalloc(MAXSYMLINKS * sizeof(struct saved),
+ GFP_KERNEL);
+ if (unlikely(!p))
+ return -ENOMEM;
+ }
memcpy(p, nd->internal, sizeof(nd->internal));
nd->stack = p;
return 0;
@@ -1561,12 +1569,6 @@ static int pick_link(struct nameidata *nd, struct path *link)
path_to_nameidata(link, nd);
return -ELOOP;
}
- if (nd->flags & LOOKUP_RCU) {
- if (unlikely(nd->path.mnt != link->mnt ||
- unlazy_walk(nd, link->dentry))) {
- return -ECHILD;
- }
- }
error = nd_alloc_stack(nd);
if (unlikely(error)) {
path_to_nameidata(link, nd);
@@ -1839,7 +1841,17 @@ OK:
break;

if (err) {
- const char *s = get_link(nd);
+ const char *s;
+
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(nd->link.mnt != nd->path.mnt ||
+ unlazy_walk(nd, nd->link.dentry))) {
+ err = -ECHILD;
+ break;
+ }
+ }
+
+ s = get_link(nd);

if (unlikely(IS_ERR(s))) {
err = PTR_ERR(s);
@@ -1992,7 +2004,16 @@ static void path_cleanup(struct nameidata *nd)
static int trailing_symlink(struct nameidata *nd)
{
const char *s;
- int error = may_follow_link(&nd->link, nd);
+ int error;
+
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(nd->link.mnt != nd->path.mnt ||
+ unlazy_walk(nd, nd->link.dentry))) {
+ terminate_walk(nd);
+ return -ECHILD;
+ }
+ }
+ error = may_follow_link(&nd->link, nd);
if (unlikely(error))
return error;
nd->flags |= LOOKUP_PARENT;
--
2.1.4


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