sanitize path_walk() mess
New helper: path_lookupat(). Basically, what do_path_lookup() boils to
modulo -ECHILD/-ESTALE handler. path_walk* family is gone; vfs_path_lookup()
is using link_path_walk() directly, do_path_lookup() and do_filp_open()
are using path_lookupat().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index 8c70446..f5de5bb 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1520,59 +1520,6 @@
return err;
}
-static inline int path_walk_rcu(const char *name, struct nameidata *nd)
-{
- current->total_link_count = 0;
-
- return link_path_walk(name, nd);
-}
-
-static inline int path_walk_simple(const char *name, struct nameidata *nd)
-{
- current->total_link_count = 0;
-
- return link_path_walk(name, nd);
-}
-
-static int path_walk(const char *name, struct nameidata *nd)
-{
- struct path save = nd->path;
- int result;
-
- current->total_link_count = 0;
-
- /* make sure the stuff we saved doesn't go away */
- path_get(&save);
-
- result = link_path_walk(name, nd);
- if (result == -ESTALE) {
- /* nd->path had been dropped */
- current->total_link_count = 0;
- nd->path = save;
- nd->inode = save.dentry->d_inode;
- path_get(&nd->path);
- nd->flags |= LOOKUP_REVAL;
- result = link_path_walk(name, nd);
- }
-
- path_put(&save);
-
- return result;
-}
-
-static void path_finish_rcu(struct nameidata *nd)
-{
- if (nd->flags & LOOKUP_RCU) {
- /* RCU dangling. Cancel it. */
- nd->flags &= ~LOOKUP_RCU;
- nd->root.mnt = NULL;
- rcu_read_unlock();
- br_read_unlock(vfsmount_lock);
- }
- if (nd->file)
- fput(nd->file);
-}
-
static int path_init_rcu(int dfd, const char *name, unsigned int flags, struct nameidata *nd)
{
int retval = 0;
@@ -1697,7 +1644,7 @@
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int do_path_lookup(int dfd, const char *name,
+static int path_lookupat(int dfd, const char *name,
unsigned int flags, struct nameidata *nd)
{
int retval;
@@ -1716,29 +1663,45 @@
* be handled by restarting a traditional ref-walk (which will always
* be able to complete).
*/
- retval = path_init_rcu(dfd, name, flags, nd);
+ if (flags & LOOKUP_RCU)
+ retval = path_init_rcu(dfd, name, flags, nd);
+ else
+ retval = path_init(dfd, name, flags, nd);
+
if (unlikely(retval))
return retval;
- retval = path_walk_rcu(name, nd);
- path_finish_rcu(nd);
+
+ current->total_link_count = 0;
+ retval = link_path_walk(name, nd);
+
+ if (nd->flags & LOOKUP_RCU) {
+ /* RCU dangling. Cancel it. */
+ nd->flags &= ~LOOKUP_RCU;
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ br_read_unlock(vfsmount_lock);
+ }
+
+ if (nd->file) {
+ fput(nd->file);
+ nd->file = NULL;
+ }
+
if (nd->root.mnt) {
path_put(&nd->root);
nd->root.mnt = NULL;
}
+ return retval;
+}
- if (unlikely(retval == -ECHILD || retval == -ESTALE)) {
- /* slower, locked walk */
- if (retval == -ESTALE)
- flags |= LOOKUP_REVAL;
- retval = path_init(dfd, name, flags, nd);
- if (unlikely(retval))
- return retval;
- retval = path_walk(name, nd);
- if (nd->root.mnt) {
- path_put(&nd->root);
- nd->root.mnt = NULL;
- }
- }
+static int do_path_lookup(int dfd, const char *name,
+ unsigned int flags, struct nameidata *nd)
+{
+ int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+ if (unlikely(retval == -ECHILD))
+ retval = path_lookupat(dfd, name, flags, nd);
+ if (unlikely(retval == -ESTALE))
+ retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
if (likely(!retval)) {
if (unlikely(!audit_dummy_context())) {
@@ -1746,7 +1709,6 @@
audit_inode(name, nd->path.dentry);
}
}
-
return retval;
}
@@ -1776,7 +1738,7 @@
const char *name, unsigned int flags,
struct nameidata *nd)
{
- int retval;
+ int result;
/* same as do_path_lookup */
nd->last_type = LAST_ROOT;
@@ -1790,15 +1752,27 @@
path_get(&nd->root);
nd->inode = nd->path.dentry->d_inode;
- retval = path_walk(name, nd);
- if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
+ current->total_link_count = 0;
+
+ result = link_path_walk(name, nd);
+ if (result == -ESTALE) {
+ /* nd->path had been dropped */
+ current->total_link_count = 0;
+ nd->path.dentry = dentry;
+ nd->path.mnt = mnt;
+ nd->inode = dentry->d_inode;
+ path_get(&nd->path);
+ nd->flags |= LOOKUP_REVAL;
+ result = link_path_walk(name, nd);
+ }
+ if (unlikely(!result && !audit_dummy_context() && nd->path.dentry &&
nd->inode))
audit_inode(name, nd->path.dentry);
path_put(&nd->root);
nd->root.mnt = NULL;
- return retval;
+ return result;
}
static struct dentry *__lookup_hash(struct qstr *name,
@@ -2483,24 +2457,14 @@
creat:
/* OK, have to create the file. Find the parent. */
- error = path_init_rcu(dfd, pathname,
- LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
- if (error)
- goto out_filp;
- error = path_walk_rcu(pathname, &nd);
- path_finish_rcu(&nd);
- if (unlikely(error == -ECHILD || error == -ESTALE)) {
- /* slower, locked walk */
- if (error == -ESTALE) {
+ error = path_lookupat(dfd, pathname, LOOKUP_PARENT | LOOKUP_RCU, &nd);
+ if (unlikely(error == -ECHILD))
+ error = path_lookupat(dfd, pathname, LOOKUP_PARENT, &nd);
+ if (unlikely(error == -ESTALE)) {
reval:
- flags |= LOOKUP_REVAL;
- }
- error = path_init(dfd, pathname,
- LOOKUP_PARENT | (flags & LOOKUP_REVAL), &nd);
- if (error)
- goto out_filp;
-
- error = path_walk_simple(pathname, &nd);
+ flags |= LOOKUP_REVAL;
+ error = path_lookupat(dfd, pathname,
+ LOOKUP_PARENT | LOOKUP_REVAL, &nd);
}
if (unlikely(error))
goto out_filp;