configfs: calculate the symlink target only once

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index c1f2125acf94dd41eef0d8bd019922b3d889058c..22dce2d35a4b50e7a397ed7428dcf590b228659b 100644 (file)
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -34,7 +34,7 @@ struct configfs_dirent {
        int                     s_dependent_count;
        struct list_head        s_sibling;
        struct list_head        s_children;
-       struct list_head        s_links;
+       int                     s_links;
        void                    * s_element;
        int                     s_type;
        umode_t                 s_mode;
@@ -84,7 +84,6 @@ extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
 extern struct dentry *configfs_pin_fs(void);
 extern void configfs_release_fs(void);
 
-extern struct rw_semaphore configfs_rename_sem;
 extern const struct file_operations configfs_dir_operations;
 extern const struct file_operations configfs_file_operations;
 extern const struct file_operations configfs_bin_file_operations;
@@ -97,14 +96,8 @@ extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
                            const char *symname);
 extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
 
-struct configfs_symlink {
-       struct list_head sl_list;
-       struct config_item *sl_target;
-};
-
-extern int configfs_create_link(struct configfs_symlink *sl,
-                               struct dentry *parent,
-                               struct dentry *dentry);
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
+               struct dentry *dentry, char *body);
 
 static inline struct config_item * to_item(struct dentry * dentry)
 {
@@ -132,11 +125,7 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
        spin_lock(&dentry->d_lock);
        if (!d_unhashed(dentry)) {
                struct configfs_dirent * sd = dentry->d_fsdata;
-               if (sd->s_type & CONFIGFS_ITEM_LINK) {
-                       struct configfs_symlink * sl = sd->s_element;
-                       item = config_item_get(sl->sl_target);
-               } else
-                       item = config_item_get(sd->s_element);
+               item = config_item_get(sd->s_element);
        }
        spin_unlock(&dentry->d_lock);
 

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 728d1f1ee6a9adc4c3ceb25c3e6b08c6dfbfec62..cf7b7e1d5bd7254fe174ebf22d7a02aeb67bcf35 100644 (file)
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -22,7 +22,6 @@
 #include <linux/configfs.h>
 #include "configfs_internal.h"
 
-DECLARE_RWSEM(configfs_rename_sem);
 /*
  * Protects mutations of configfs_dirent linkage together with proper i_mutex
  * Also protects mutations of symlinks linkage to target configfs_dirent
@@ -191,7 +190,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
                return ERR_PTR(-ENOMEM);
 
        atomic_set(&sd->s_count, 1);
-       INIT_LIST_HEAD(&sd->s_links);
        INIT_LIST_HEAD(&sd->s_children);
        sd->s_element = element;
        sd->s_type = type;
@@ -353,17 +351,16 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd)
        return ret;
 }
 
-int configfs_create_link(struct configfs_symlink *sl,
-                        struct dentry *parent,
-                        struct dentry *dentry)
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
+               struct dentry *dentry, char *body)
 {
        int err = 0;
        umode_t mode = S_IFLNK | S_IRWXUGO;
        struct configfs_dirent *p = parent->d_fsdata;
        struct inode *inode;
 
-       err = configfs_make_dirent(p, dentry, sl, mode,
-                                  CONFIGFS_ITEM_LINK, p->s_frag);
+       err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
+                       p->s_frag);
        if (err)
                return err;
 
@@ -371,6 +368,7 @@ int configfs_create_link(struct configfs_symlink *sl,
        if (IS_ERR(inode))
                goto out_remove;
 
+       inode->i_link = body;
        inode->i_op = &configfs_symlink_inode_operations;
        d_instantiate(dentry, inode);
        dget(dentry);  /* pin link dentries in core */
@@ -517,7 +515,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
        parent_sd->s_type |= CONFIGFS_USET_DROPPING;
 
        ret = -EBUSY;
-       if (!list_empty(&parent_sd->s_links))
+       if (parent_sd->s_links)
                goto out;
 
        ret = 0;
@@ -1575,44 +1573,6 @@ const struct inode_operations configfs_root_inode_operations = {
        .setattr        = configfs_setattr,
 };
 
-#if 0
-int configfs_rename_dir(struct config_item * item, const char *new_name)
-{
-       int error = 0;
-       struct dentry * new_dentry, * parent;
-
-       if (!strcmp(config_item_name(item), new_name))
-               return -EINVAL;
-
-       if (!item->parent)
-               return -EINVAL;
-
-       down_write(&configfs_rename_sem);
-       parent = item->parent->dentry;
-
-       inode_lock(d_inode(parent));
-
-       new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
-       if (!IS_ERR(new_dentry)) {
-               if (d_really_is_negative(new_dentry)) {
-                       error = config_item_set_name(item, "%s", new_name);
-                       if (!error) {
-                               d_add(new_dentry, NULL);
-                               d_move(item->dentry, new_dentry);
-                       }
-                       else
-                               d_delete(new_dentry);
-               } else
-                       error = -EEXIST;
-               dput(new_dentry);
-       }
-       inode_unlock(d_inode(parent));
-       up_write(&configfs_rename_sem);
-
-       return error;
-}
-#endif
-
 static int configfs_dir_open(struct inode *inode, struct file *file)
 {
        struct dentry * dentry = file->f_path.dentry;

diff --git a/fs/configfs/mount.c b/fs/configfs/mount.c
index 55438dd58189934e7498f88a461c4dc6f83d2ece..0c6e8cf6195300c706bb04f2be4738a54f0d785f 100644 (file)
--- a/fs/configfs/mount.c
+++ b/fs/configfs/mount.c
@@ -28,9 +28,18 @@ static struct vfsmount *configfs_mount = NULL;
 struct kmem_cache *configfs_dir_cachep;
 static int configfs_mnt_count = 0;
 
+
+static void configfs_free_inode(struct inode *inode)
+{
+       if (S_ISLNK(inode->i_mode))
+               kfree(inode->i_link);
+       free_inode_nonrcu(inode);
+}
+
 static const struct super_operations configfs_ops = {
        .statfs         = simple_statfs,
        .drop_inode     = generic_delete_inode,
+       .free_inode     = configfs_free_inode,
 };
 
 static struct config_group configfs_root_group = {

diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c
index f3881e4caedd8f91085f8d5c00c9a9112ff46698..dc5dbf6a81d77bde5bcaad94cb2f4e37a6296ede 100644 (file)
--- a/fs/configfs/symlink.c
+++ b/fs/configfs/symlink.c
@@ -55,41 +55,63 @@ static void fill_item_path(struct config_item * item, char * buffer, int length)
        }
 }
 
+static int configfs_get_target_path(struct config_item *item,
+               struct config_item *target, char *path)
+{
+       int depth, size;
+       char *s;
+
+       depth = item_depth(item);
+       size = item_path_length(target) + depth * 3 - 1;
+       if (size > PATH_MAX)
+               return -ENAMETOOLONG;
+
+       pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
+
+       for (s = path; depth--; s += 3)
+               strcpy(s,"../");
+
+       fill_item_path(target, path, size);
+       pr_debug("%s: path = '%s'\n", __func__, path);
+       return 0;
+}
+
 static int create_link(struct config_item *parent_item,
                       struct config_item *item,
                       struct dentry *dentry)
 {
        struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;
-       struct configfs_symlink *sl;
+       char *body;
        int ret;
 
-       ret = -ENOENT;
        if (!configfs_dirent_is_ready(target_sd))
-               goto out;
-       ret = -ENOMEM;
-       sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
-       if (sl) {
+               return -ENOENT;
+
+       body = kzalloc(PAGE_SIZE, GFP_KERNEL);
+       if (!body)
+               return -ENOMEM;
+
+       configfs_get(target_sd);
+       spin_lock(&configfs_dirent_lock);
+       if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
+               spin_unlock(&configfs_dirent_lock);
+               configfs_put(target_sd);
+               kfree(body);
+               return -ENOENT;
+       }
+       target_sd->s_links++;
+       spin_unlock(&configfs_dirent_lock);
+       ret = configfs_get_target_path(item, item, body);
+       if (!ret)
+               ret = configfs_create_link(target_sd, parent_item->ci_dentry,
+                                          dentry, body);
+       if (ret) {
                spin_lock(&configfs_dirent_lock);
-               if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
-                       spin_unlock(&configfs_dirent_lock);
-                       kfree(sl);
-                       return -ENOENT;
-               }
-               sl->sl_target = config_item_get(item);
-               list_add(&sl->sl_list, &target_sd->s_links);
+               target_sd->s_links--;
                spin_unlock(&configfs_dirent_lock);
-               ret = configfs_create_link(sl, parent_item->ci_dentry,
-                                          dentry);
-               if (ret) {
-                       spin_lock(&configfs_dirent_lock);
-                       list_del_init(&sl->sl_list);
-                       spin_unlock(&configfs_dirent_lock);
-                       config_item_put(item);
-                       kfree(sl);
-               }
+               configfs_put(target_sd);
+               kfree(body);
        }
-
-out:
        return ret;
 }
 
@@ -131,9 +153,8 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
         * Fake invisibility if dir belongs to a group/default groups hierarchy
         * being attached
         */
-       ret = -ENOENT;
        if (!configfs_dirent_is_ready(sd))
-               goto out;
+               return -ENOENT;
 
        parent_item = configfs_get_config_item(dentry->d_parent);
        type = parent_item->ci_type;
@@ -193,15 +214,12 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
 
 out_put:
        config_item_put(parent_item);
-
-out:
        return ret;
 }
 
 int configfs_unlink(struct inode *dir, struct dentry *dentry)
 {
-       struct configfs_dirent *sd = dentry->d_fsdata;
-       struct configfs_symlink *sl;
+       struct configfs_dirent *sd = dentry->d_fsdata, *target_sd;
        struct config_item *parent_item;
        const struct config_item_type *type;
        int ret;
@@ -210,7 +228,7 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
        if (!(sd->s_type & CONFIGFS_ITEM_LINK))
                goto out;
 
-       sl = sd->s_element;
+       target_sd = sd->s_element;
 
        parent_item = configfs_get_config_item(dentry->d_parent);
        type = parent_item->ci_type;
@@ -224,21 +242,18 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
 
        /*
         * drop_link() must be called before
-        * list_del_init(&sl->sl_list), so that the order of
+        * decrementing target's ->s_links, so that the order of
         * drop_link(this, target) and drop_item(target) is preserved.
         */
        if (type && type->ct_item_ops &&
            type->ct_item_ops->drop_link)
                type->ct_item_ops->drop_link(parent_item,
-                                              sl->sl_target);
+                                              target_sd->s_element);
 
        spin_lock(&configfs_dirent_lock);
-       list_del_init(&sl->sl_list);
+       target_sd->s_links--;
        spin_unlock(&configfs_dirent_lock);
-
-       /* Put reference from create_link() */
-       config_item_put(sl->sl_target);
-       kfree(sl);
+       configfs_put(target_sd);
 
        config_item_put(parent_item);
 
@@ -248,79 +263,8 @@ out:
        return ret;
 }
 
-static int configfs_get_target_path(struct config_item * item, struct config_item * target,
-                                  char *path)
-{
-       char * s;
-       int depth, size;
-
-       depth = item_depth(item);
-       size = item_path_length(target) + depth * 3 - 1;
-       if (size > PATH_MAX)
-               return -ENAMETOOLONG;
-
-       pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
-
-       for (s = path; depth--; s += 3)
-               strcpy(s,"../");
-
-       fill_item_path(target, path, size);
-       pr_debug("%s: path = '%s'\n", __func__, path);
-
-       return 0;
-}
-
-static int configfs_getlink(struct dentry *dentry, char * path)
-{
-       struct config_item *item, *target_item;
-       int error = 0;
-
-       item = configfs_get_config_item(dentry->d_parent);
-       if (!item)
-               return -EINVAL;
-
-       target_item = configfs_get_config_item(dentry);
-       if (!target_item) {
-               config_item_put(item);
-               return -EINVAL;
-       }
-
-       down_read(&configfs_rename_sem);
-       error = configfs_get_target_path(item, target_item, path);
-       up_read(&configfs_rename_sem);
-
-       config_item_put(item);
-       config_item_put(target_item);
-       return error;
-
-}
-
-static const char *configfs_get_link(struct dentry *dentry,
-                                    struct inode *inode,
-                                    struct delayed_call *done)
-{
-       char *body;
-       int error;
-
-       if (!dentry)
-               return ERR_PTR(-ECHILD);
-
-       body = kzalloc(PAGE_SIZE, GFP_KERNEL);
-       if (!body)
-               return ERR_PTR(-ENOMEM);
-
-       error = configfs_getlink(dentry, body);
-       if (!error) {
-               set_delayed_call(done, kfree_link, body);
-               return body;
-       }
-
-       kfree(body);
-       return ERR_PTR(error);
-}
-
 const struct inode_operations configfs_symlink_inode_operations = {
-       .get_link = configfs_get_link,
+       .get_link = simple_get_link,
        .setattr = configfs_setattr,
 };