forked from Minki/linux
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>
This commit is contained in:
Al Viro
Christoph Hellwig
parent
2743c515a1
commit
e9c03af21c
@ -34,7 +34,7 @@ struct configfs_dirent {
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int s_dependent_count;
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struct list_head s_sibling;
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struct list_head s_children;
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struct list_head s_links;
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int s_links;
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void * s_element;
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int s_type;
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umode_t s_mode;
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@ -84,7 +84,6 @@ extern int configfs_setattr(struct dentry *dentry, struct iattr *iattr);
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extern struct dentry *configfs_pin_fs(void);
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extern void configfs_release_fs(void);
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extern struct rw_semaphore configfs_rename_sem;
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extern const struct file_operations configfs_dir_operations;
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extern const struct file_operations configfs_file_operations;
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extern const struct file_operations configfs_bin_file_operations;
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@ -97,14 +96,8 @@ extern int configfs_symlink(struct inode *dir, struct dentry *dentry,
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const char *symname);
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extern int configfs_unlink(struct inode *dir, struct dentry *dentry);
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struct configfs_symlink {
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struct list_head sl_list;
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struct config_item *sl_target;
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};
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extern int configfs_create_link(struct configfs_symlink *sl,
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struct dentry *parent,
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struct dentry *dentry);
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int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
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struct dentry *dentry, char *body);
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static inline struct config_item * to_item(struct dentry * dentry)
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{
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@ -132,10 +125,6 @@ static inline struct config_item *configfs_get_config_item(struct dentry *dentry
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spin_lock(&dentry->d_lock);
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if (!d_unhashed(dentry)) {
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struct configfs_dirent * sd = dentry->d_fsdata;
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if (sd->s_type & CONFIGFS_ITEM_LINK) {
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struct configfs_symlink * sl = sd->s_element;
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item = config_item_get(sl->sl_target);
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} else
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item = config_item_get(sd->s_element);
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}
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spin_unlock(&dentry->d_lock);
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@ -22,7 +22,6 @@
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#include <linux/configfs.h>
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#include "configfs_internal.h"
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DECLARE_RWSEM(configfs_rename_sem);
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/*
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* Protects mutations of configfs_dirent linkage together with proper i_mutex
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* Also protects mutations of symlinks linkage to target configfs_dirent
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@ -191,7 +190,6 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren
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return ERR_PTR(-ENOMEM);
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atomic_set(&sd->s_count, 1);
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INIT_LIST_HEAD(&sd->s_links);
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INIT_LIST_HEAD(&sd->s_children);
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sd->s_element = element;
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sd->s_type = type;
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@ -353,17 +351,16 @@ int configfs_dirent_is_ready(struct configfs_dirent *sd)
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return ret;
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}
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int configfs_create_link(struct configfs_symlink *sl,
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struct dentry *parent,
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struct dentry *dentry)
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int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
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struct dentry *dentry, char *body)
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{
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int err = 0;
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umode_t mode = S_IFLNK | S_IRWXUGO;
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struct configfs_dirent *p = parent->d_fsdata;
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struct inode *inode;
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err = configfs_make_dirent(p, dentry, sl, mode,
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CONFIGFS_ITEM_LINK, p->s_frag);
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err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
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p->s_frag);
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if (err)
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return err;
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@ -371,6 +368,7 @@ int configfs_create_link(struct configfs_symlink *sl,
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if (IS_ERR(inode))
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goto out_remove;
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inode->i_link = body;
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inode->i_op = &configfs_symlink_inode_operations;
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d_instantiate(dentry, inode);
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dget(dentry); /* pin link dentries in core */
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@ -517,7 +515,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
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parent_sd->s_type |= CONFIGFS_USET_DROPPING;
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ret = -EBUSY;
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if (!list_empty(&parent_sd->s_links))
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if (parent_sd->s_links)
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goto out;
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ret = 0;
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@ -1575,44 +1573,6 @@ const struct inode_operations configfs_root_inode_operations = {
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.setattr = configfs_setattr,
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};
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#if 0
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int configfs_rename_dir(struct config_item * item, const char *new_name)
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{
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int error = 0;
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struct dentry * new_dentry, * parent;
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if (!strcmp(config_item_name(item), new_name))
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return -EINVAL;
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if (!item->parent)
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return -EINVAL;
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down_write(&configfs_rename_sem);
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parent = item->parent->dentry;
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inode_lock(d_inode(parent));
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new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
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if (!IS_ERR(new_dentry)) {
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if (d_really_is_negative(new_dentry)) {
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error = config_item_set_name(item, "%s", new_name);
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if (!error) {
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d_add(new_dentry, NULL);
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d_move(item->dentry, new_dentry);
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}
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else
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d_delete(new_dentry);
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} else
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error = -EEXIST;
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dput(new_dentry);
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}
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inode_unlock(d_inode(parent));
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up_write(&configfs_rename_sem);
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return error;
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}
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#endif
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static int configfs_dir_open(struct inode *inode, struct file *file)
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{
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struct dentry * dentry = file->f_path.dentry;
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@ -28,9 +28,18 @@ static struct vfsmount *configfs_mount = NULL;
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struct kmem_cache *configfs_dir_cachep;
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static int configfs_mnt_count = 0;
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static void configfs_free_inode(struct inode *inode)
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{
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if (S_ISLNK(inode->i_mode))
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kfree(inode->i_link);
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free_inode_nonrcu(inode);
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}
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static const struct super_operations configfs_ops = {
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.statfs = simple_statfs,
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.drop_inode = generic_delete_inode,
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.free_inode = configfs_free_inode,
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};
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static struct config_group configfs_root_group = {
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@ -55,41 +55,63 @@ static void fill_item_path(struct config_item * item, char * buffer, int length)
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}
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}
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static int configfs_get_target_path(struct config_item *item,
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struct config_item *target, char *path)
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{
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int depth, size;
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char *s;
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depth = item_depth(item);
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size = item_path_length(target) + depth * 3 - 1;
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if (size > PATH_MAX)
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return -ENAMETOOLONG;
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pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
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for (s = path; depth--; s += 3)
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strcpy(s,"../");
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fill_item_path(target, path, size);
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pr_debug("%s: path = '%s'\n", __func__, path);
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return 0;
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}
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static int create_link(struct config_item *parent_item,
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struct config_item *item,
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struct dentry *dentry)
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{
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struct configfs_dirent *target_sd = item->ci_dentry->d_fsdata;
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struct configfs_symlink *sl;
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char *body;
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int ret;
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ret = -ENOENT;
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if (!configfs_dirent_is_ready(target_sd))
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goto out;
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ret = -ENOMEM;
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sl = kmalloc(sizeof(struct configfs_symlink), GFP_KERNEL);
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if (sl) {
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return -ENOENT;
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body = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!body)
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return -ENOMEM;
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configfs_get(target_sd);
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spin_lock(&configfs_dirent_lock);
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if (target_sd->s_type & CONFIGFS_USET_DROPPING) {
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spin_unlock(&configfs_dirent_lock);
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kfree(sl);
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configfs_put(target_sd);
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kfree(body);
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return -ENOENT;
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}
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sl->sl_target = config_item_get(item);
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list_add(&sl->sl_list, &target_sd->s_links);
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target_sd->s_links++;
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spin_unlock(&configfs_dirent_lock);
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ret = configfs_create_link(sl, parent_item->ci_dentry,
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dentry);
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ret = configfs_get_target_path(item, item, body);
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if (!ret)
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ret = configfs_create_link(target_sd, parent_item->ci_dentry,
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dentry, body);
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if (ret) {
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sl->sl_list);
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target_sd->s_links--;
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spin_unlock(&configfs_dirent_lock);
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config_item_put(item);
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kfree(sl);
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configfs_put(target_sd);
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kfree(body);
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}
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}
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out:
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return ret;
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}
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@ -131,9 +153,8 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
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* Fake invisibility if dir belongs to a group/default groups hierarchy
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* being attached
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*/
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ret = -ENOENT;
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if (!configfs_dirent_is_ready(sd))
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goto out;
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return -ENOENT;
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parent_item = configfs_get_config_item(dentry->d_parent);
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type = parent_item->ci_type;
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@ -193,15 +214,12 @@ int configfs_symlink(struct inode *dir, struct dentry *dentry, const char *symna
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out_put:
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config_item_put(parent_item);
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out:
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return ret;
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}
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int configfs_unlink(struct inode *dir, struct dentry *dentry)
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{
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struct configfs_dirent *sd = dentry->d_fsdata;
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struct configfs_symlink *sl;
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struct configfs_dirent *sd = dentry->d_fsdata, *target_sd;
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struct config_item *parent_item;
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const struct config_item_type *type;
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int ret;
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@ -210,7 +228,7 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
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if (!(sd->s_type & CONFIGFS_ITEM_LINK))
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goto out;
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sl = sd->s_element;
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target_sd = sd->s_element;
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parent_item = configfs_get_config_item(dentry->d_parent);
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type = parent_item->ci_type;
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@ -224,21 +242,18 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry)
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/*
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* drop_link() must be called before
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* list_del_init(&sl->sl_list), so that the order of
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* decrementing target's ->s_links, so that the order of
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* drop_link(this, target) and drop_item(target) is preserved.
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*/
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if (type && type->ct_item_ops &&
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type->ct_item_ops->drop_link)
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type->ct_item_ops->drop_link(parent_item,
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sl->sl_target);
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target_sd->s_element);
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spin_lock(&configfs_dirent_lock);
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list_del_init(&sl->sl_list);
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target_sd->s_links--;
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spin_unlock(&configfs_dirent_lock);
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/* Put reference from create_link() */
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config_item_put(sl->sl_target);
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kfree(sl);
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configfs_put(target_sd);
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config_item_put(parent_item);
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@ -248,79 +263,8 @@ out:
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return ret;
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}
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static int configfs_get_target_path(struct config_item * item, struct config_item * target,
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char *path)
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{
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char * s;
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int depth, size;
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depth = item_depth(item);
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size = item_path_length(target) + depth * 3 - 1;
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if (size > PATH_MAX)
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return -ENAMETOOLONG;
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pr_debug("%s: depth = %d, size = %d\n", __func__, depth, size);
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for (s = path; depth--; s += 3)
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strcpy(s,"../");
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fill_item_path(target, path, size);
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pr_debug("%s: path = '%s'\n", __func__, path);
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return 0;
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}
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static int configfs_getlink(struct dentry *dentry, char * path)
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{
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struct config_item *item, *target_item;
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int error = 0;
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item = configfs_get_config_item(dentry->d_parent);
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if (!item)
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return -EINVAL;
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target_item = configfs_get_config_item(dentry);
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if (!target_item) {
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config_item_put(item);
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return -EINVAL;
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}
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down_read(&configfs_rename_sem);
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error = configfs_get_target_path(item, target_item, path);
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up_read(&configfs_rename_sem);
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config_item_put(item);
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config_item_put(target_item);
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return error;
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}
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static const char *configfs_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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char *body;
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int error;
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if (!dentry)
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return ERR_PTR(-ECHILD);
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body = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!body)
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return ERR_PTR(-ENOMEM);
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error = configfs_getlink(dentry, body);
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if (!error) {
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set_delayed_call(done, kfree_link, body);
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return body;
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}
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kfree(body);
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return ERR_PTR(error);
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}
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const struct inode_operations configfs_symlink_inode_operations = {
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.get_link = configfs_get_link,
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.get_link = simple_get_link,
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.setattr = configfs_setattr,
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};
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