Get rid of symlink body copying
Now that nd->last stays around until ->put_link() is called, we can
just postpone that ->put_link() in do_filp_open() a bit and don't
bother with copying.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index adfbaf5..1f5d86d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -498,8 +498,6 @@
static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
{
- int res = 0;
- char *name;
if (IS_ERR(link))
goto fail;
@@ -510,22 +508,7 @@
path_get(&nd->root);
}
- res = link_path_walk(link, nd);
- if (nd->depth || res || nd->last_type!=LAST_NORM)
- return res;
- /*
- * If it is an iterative symlinks resolution in open_namei() we
- * have to copy the last component. And all that crap because of
- * bloody create() on broken symlinks. Furrfu...
- */
- name = __getname();
- if (unlikely(!name)) {
- path_put(&nd->path);
- return -ENOMEM;
- }
- strcpy(name, nd->last.name);
- nd->last.name = name;
- return 0;
+ return link_path_walk(link, nd);
fail:
path_put(&nd->path);
return PTR_ERR(link);
@@ -547,10 +530,10 @@
nd->path.dentry = path->dentry;
}
-static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd)
+static __always_inline int
+__do_follow_link(struct path *path, struct nameidata *nd, void **p)
{
int error;
- void *cookie;
struct dentry *dentry = path->dentry;
touch_atime(path->mnt, dentry);
@@ -562,9 +545,9 @@
}
mntget(path->mnt);
nd->last_type = LAST_BIND;
- cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
- error = PTR_ERR(cookie);
- if (!IS_ERR(cookie)) {
+ *p = dentry->d_inode->i_op->follow_link(dentry, nd);
+ error = PTR_ERR(*p);
+ if (!IS_ERR(*p)) {
char *s = nd_get_link(nd);
error = 0;
if (s)
@@ -574,8 +557,6 @@
if (error)
path_put(&nd->path);
}
- if (dentry->d_inode->i_op->put_link)
- dentry->d_inode->i_op->put_link(dentry, nd, cookie);
}
return error;
}
@@ -589,6 +570,7 @@
*/
static inline int do_follow_link(struct path *path, struct nameidata *nd)
{
+ void *cookie;
int err = -ELOOP;
if (current->link_count >= MAX_NESTED_LINKS)
goto loop;
@@ -602,7 +584,9 @@
current->link_count++;
current->total_link_count++;
nd->depth++;
- err = __do_follow_link(path, nd);
+ err = __do_follow_link(path, nd, &cookie);
+ if (!IS_ERR(cookie) && path->dentry->d_inode->i_op->put_link)
+ path->dentry->d_inode->i_op->put_link(path->dentry, nd, cookie);
path_put(path);
current->link_count--;
nd->depth--;
@@ -1847,6 +1831,9 @@
nd.flags |= LOOKUP_EXCL;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
while (unlikely(!filp)) { /* trailing symlink */
+ struct path holder;
+ struct inode *inode;
+ void *cookie;
error = -ELOOP;
if ((open_flag & O_NOFOLLOW) || count++ == 32)
goto exit_dput;
@@ -1865,18 +1852,24 @@
error = security_inode_follow_link(path.dentry, &nd);
if (error)
goto exit_dput;
- error = __do_follow_link(&path, &nd);
- path_put(&path);
- if (error) {
+ error = __do_follow_link(&path, &nd, &cookie);
+ if (unlikely(error)) {
/* nd.path had been dropped */
+ inode = path.dentry->d_inode;
+ if (!IS_ERR(cookie) && inode->i_op->put_link)
+ inode->i_op->put_link(path.dentry, &nd, cookie);
+ path_put(&path);
release_open_intent(&nd);
filp = ERR_PTR(error);
goto out;
}
+ holder = path;
nd.flags &= ~LOOKUP_PARENT;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
- if (nd.last_type == LAST_NORM)
- __putname(nd.last.name);
+ inode = holder.dentry->d_inode;
+ if (inode->i_op->put_link)
+ inode->i_op->put_link(holder.dentry, &nd, cookie);
+ path_put(&holder);
}
out:
if (nd.root.mnt)