switch ->get_link() to delayed_call, kill ->put_link()

[mirror_ubuntu-zesty-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 8f517888c3e10779ae551b0410b8d80760620436..3c909aebef70f8a8a091960bd3ba434a15e2f829 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -505,13 +505,13 @@ struct nameidata {
        int             total_link_count;
        struct saved {
                struct path link;
-               void *cookie;
+               struct delayed_call done;
                const char *name;
-               struct inode *inode;
                unsigned seq;
        } *stack, internal[EMBEDDED_LEVELS];
        struct filename *name;
        struct nameidata *saved;
+       struct inode    *link_inode;
        unsigned        root_seq;
        int             dfd;
 };
@@ -592,11 +592,8 @@ static void drop_links(struct nameidata *nd)
        int i = nd->depth;
        while (i--) {
                struct saved *last = nd->stack + i;
-               struct inode *inode = last->inode;
-               if (last->cookie && inode->i_op->put_link) {
-                       inode->i_op->put_link(inode, last->cookie);
-                       last->cookie = NULL;
-               }
+               do_delayed_call(&last->done);
+               clear_delayed_call(&last->done);
        }
 }
 
@@ -858,9 +855,7 @@ void nd_jump_link(struct path *path)
 static inline void put_link(struct nameidata *nd)
 {
        struct saved *last = nd->stack + --nd->depth;
-       struct inode *inode = last->inode;
-       if (last->cookie && inode->i_op->put_link)
-               inode->i_op->put_link(inode, last->cookie);
+       do_delayed_call(&last->done);
        if (!(nd->flags & LOOKUP_RCU))
                path_put(&last->link);
 }
@@ -892,7 +887,7 @@ static inline int may_follow_link(struct nameidata *nd)
                return 0;
 
        /* Allowed if owner and follower match. */
-       inode = nd->stack[0].inode;
+       inode = nd->link_inode;
        if (uid_eq(current_cred()->fsuid, inode->i_uid))
                return 0;
 
@@ -983,7 +978,7 @@ const char *get_link(struct nameidata *nd)
 {
        struct saved *last = nd->stack + nd->depth - 1;
        struct dentry *dentry = last->link.dentry;
-       struct inode *inode = last->inode;
+       struct inode *inode = nd->link_inode;
        int error;
        const char *res;
 
@@ -1004,23 +999,21 @@ const char *get_link(struct nameidata *nd)
        nd->last_type = LAST_BIND;
        res = inode->i_link;
        if (!res) {
+               const char * (*get)(struct dentry *, struct inode *,
+                               struct delayed_call *);
+               get = inode->i_op->get_link;
                if (nd->flags & LOOKUP_RCU) {
-                       res = inode->i_op->get_link(NULL, inode,
-                                                   &last->cookie);
+                       res = get(NULL, inode, &last->done);
                        if (res == ERR_PTR(-ECHILD)) {
                                if (unlikely(unlazy_walk(nd, NULL, 0)))
                                        return ERR_PTR(-ECHILD);
-                               res = inode->i_op->get_link(dentry, inode,
-                                                           &last->cookie);
+                               res = get(dentry, inode, &last->done);
                        }
                } else {
-                       res = inode->i_op->get_link(dentry, inode,
-                                                   &last->cookie);
+                       res = get(dentry, inode, &last->done);
                }
-               if (IS_ERR_OR_NULL(res)) {
-                       last->cookie = NULL;
+               if (IS_ERR_OR_NULL(res))
                        return res;
-               }
        }
        if (*res == '/') {
                if (nd->flags & LOOKUP_RCU) {
@@ -1699,8 +1692,8 @@ static int pick_link(struct nameidata *nd, struct path *link,
 
        last = nd->stack + nd->depth++;
        last->link = *link;
-       last->cookie = NULL;
-       last->inode = inode;
+       clear_delayed_call(&last->done);
+       nd->link_inode = inode;
        last->seq = seq;
        return 1;
 }
@@ -4508,26 +4501,25 @@ EXPORT_SYMBOL(readlink_copy);
  */
 int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
-       void *cookie;
+       DEFINE_DELAYED_CALL(done);
        struct inode *inode = d_inode(dentry);
        const char *link = inode->i_link;
        int res;
 
        if (!link) {
-               link = inode->i_op->get_link(dentry, inode, &cookie);
+               link = inode->i_op->get_link(dentry, inode, &done);
                if (IS_ERR(link))
                        return PTR_ERR(link);
        }
        res = readlink_copy(buffer, buflen, link);
-       if (inode->i_op->put_link)
-               inode->i_op->put_link(inode, cookie);
+       do_delayed_call(&done);
        return res;
 }
 EXPORT_SYMBOL(generic_readlink);
 
 /* get the link contents into pagecache */
 const char *page_get_link(struct dentry *dentry, struct inode *inode,
-                                void **cookie)
+                         struct delayed_call *callback)
 {
        char *kaddr;
        struct page *page;
@@ -4546,7 +4538,7 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,
                if (IS_ERR(page))
                        return (char*)page;
        }
-       *cookie = page;
+       set_delayed_call(callback, page_put_link, page);
        BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
        kaddr = page_address(page);
        nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
@@ -4555,21 +4547,19 @@ const char *page_get_link(struct dentry *dentry, struct inode *inode,
 
 EXPORT_SYMBOL(page_get_link);
 
-void page_put_link(struct inode *unused, void *cookie)
+void page_put_link(void *arg)
 {
-       struct page *page = cookie;
-       page_cache_release(page);
+       put_page(arg);
 }
 EXPORT_SYMBOL(page_put_link);
 
 int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
-       void *cookie = NULL;
+       DEFINE_DELAYED_CALL(done);
        int res = readlink_copy(buffer, buflen,
                                page_get_link(dentry, d_inode(dentry),
-                                             &cookie));
-       if (cookie)
-               page_put_link(NULL, cookie);
+                                             &done));
+       do_delayed_call(&done);
        return res;
 }
 EXPORT_SYMBOL(page_readlink);
@@ -4619,6 +4609,5 @@ EXPORT_SYMBOL(page_symlink);
 const struct inode_operations page_symlink_inode_operations = {
        .readlink       = generic_readlink,
        .get_link       = page_get_link,
-       .put_link       = page_put_link,
 };
 EXPORT_SYMBOL(page_symlink_inode_operations);