diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h index 5c20e83315bc..0b969d0eb8ff 100644 --- a/fs/configfs/configfs_internal.h +++ b/fs/configfs/configfs_internal.h @@ -55,6 +55,8 @@ struct configfs_dirent { #define CONFIGFS_USET_IN_MKDIR 0x0200 #define CONFIGFS_USET_CREATING 0x0400 #define CONFIGFS_NOT_PINNED (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR) +#define CONFIGFS_PINNED \ + (CONFIGFS_ROOT | CONFIGFS_DIR | CONFIGFS_ITEM_LINK) extern struct mutex configfs_symlink_mutex; extern spinlock_t configfs_dirent_lock; diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 43d6bde1adcc..7d10278db30d 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -207,7 +207,17 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren return ERR_PTR(-ENOENT); } sd->s_frag = get_fragment(frag); - list_add(&sd->s_sibling, &parent_sd->s_children); + + /* + * configfs_lookup scans only for unpinned items. s_children is + * partitioned so that configfs_lookup can bail out early. + * CONFIGFS_PINNED and CONFIGFS_NOT_PINNED are not symmetrical. readdir + * cursors still need to be inserted at the front of the list. + */ + if (sd->s_type & CONFIGFS_PINNED) + list_add_tail(&sd->s_sibling, &parent_sd->s_children); + else + list_add(&sd->s_sibling, &parent_sd->s_children); spin_unlock(&configfs_dirent_lock); return sd; @@ -220,10 +230,11 @@ static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *paren * * called with parent inode's i_mutex held */ -static int configfs_dirent_exists(struct configfs_dirent *parent_sd, - const unsigned char *new) +static int configfs_dirent_exists(struct dentry *dentry) { - struct configfs_dirent * sd; + struct configfs_dirent *parent_sd = dentry->d_parent->d_fsdata; + const unsigned char *new = dentry->d_name.name; + struct configfs_dirent *sd; list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (sd->s_element) { @@ -289,10 +300,6 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry, BUG_ON(!item); - error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name); - if (unlikely(error)) - return error; - error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, CONFIGFS_DIR | CONFIGFS_USET_CREATING, frag); @@ -451,6 +458,18 @@ static struct dentry * configfs_lookup(struct inode *dir, spin_lock(&configfs_dirent_lock); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + + /* + * s_children is partitioned, see configfs_new_dirent. The first + * pinned item indicates we can stop scanning. + */ + if (sd->s_type & CONFIGFS_PINNED) + break; + + /* + * Note: CONFIGFS_PINNED and CONFIGFS_NOT_PINNED are asymmetric. + * there may be a readdir cursor in this list + */ if ((sd->s_type & CONFIGFS_NOT_PINNED) && !strcmp(configfs_get_name(sd), dentry->d_name.name)) { struct configfs_attribute *attr = sd->s_element; @@ -1885,8 +1904,11 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) if (dentry) { d_add(dentry, NULL); - err = configfs_attach_group(sd->s_element, &group->cg_item, - dentry, frag); + err = configfs_dirent_exists(dentry); + if (!err) + err = configfs_attach_group(sd->s_element, + &group->cg_item, + dentry, frag); if (err) { BUG_ON(d_inode(dentry)); d_drop(dentry);