diff options
Diffstat (limited to 'fs/configfs/inode.c')
| -rw-r--r-- | fs/configfs/inode.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c new file mode 100644 index 000000000..b601610e9 --- /dev/null +++ b/fs/configfs/inode.c @@ -0,0 +1,244 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * inode.c - basic inode and dentry operations. + * + * Based on sysfs: + * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel + * + * configfs Copyright (C) 2005 Oracle. All rights reserved. + * + * Please see Documentation/filesystems/configfs.rst for more + * information. + */ + +#undef DEBUG + +#include <linux/pagemap.h> +#include <linux/namei.h> +#include <linux/backing-dev.h> +#include <linux/capability.h> +#include <linux/sched.h> +#include <linux/lockdep.h> +#include <linux/slab.h> + +#include <linux/configfs.h> +#include "configfs_internal.h" + +#ifdef CONFIG_LOCKDEP +static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; +#endif + +static const struct inode_operations configfs_inode_operations ={ + .setattr = configfs_setattr, +}; + +int configfs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct iattr *iattr) +{ + struct inode * inode = d_inode(dentry); + struct configfs_dirent * sd = dentry->d_fsdata; + struct iattr * sd_iattr; + unsigned int ia_valid = iattr->ia_valid; + int error; + + if (!sd) + return -EINVAL; + + sd_iattr = sd->s_iattr; + if (!sd_iattr) { + /* setting attributes for the first time, allocate now */ + sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); + if (!sd_iattr) + return -ENOMEM; + /* assign default attributes */ + sd_iattr->ia_mode = sd->s_mode; + sd_iattr->ia_uid = GLOBAL_ROOT_UID; + sd_iattr->ia_gid = GLOBAL_ROOT_GID; + sd_iattr->ia_atime = sd_iattr->ia_mtime = + sd_iattr->ia_ctime = current_time(inode); + sd->s_iattr = sd_iattr; + } + /* attributes were changed atleast once in past */ + + error = simple_setattr(mnt_userns, dentry, iattr); + if (error) + return error; + + if (ia_valid & ATTR_UID) + sd_iattr->ia_uid = iattr->ia_uid; + if (ia_valid & ATTR_GID) + sd_iattr->ia_gid = iattr->ia_gid; + if (ia_valid & ATTR_ATIME) + sd_iattr->ia_atime = iattr->ia_atime; + if (ia_valid & ATTR_MTIME) + sd_iattr->ia_mtime = iattr->ia_mtime; + if (ia_valid & ATTR_CTIME) + sd_iattr->ia_ctime = iattr->ia_ctime; + if (ia_valid & ATTR_MODE) { + umode_t mode = iattr->ia_mode; + + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) + mode &= ~S_ISGID; + sd_iattr->ia_mode = sd->s_mode = mode; + } + + return error; +} + +static inline void set_default_inode_attr(struct inode * inode, umode_t mode) +{ + inode->i_mode = mode; + inode->i_atime = inode->i_mtime = + inode->i_ctime = current_time(inode); +} + +static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) +{ + inode->i_mode = iattr->ia_mode; + inode->i_uid = iattr->ia_uid; + inode->i_gid = iattr->ia_gid; + inode->i_atime = iattr->ia_atime; + inode->i_mtime = iattr->ia_mtime; + inode->i_ctime = iattr->ia_ctime; +} + +struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd, + struct super_block *s) +{ + struct inode * inode = new_inode(s); + if (inode) { + inode->i_ino = get_next_ino(); + inode->i_mapping->a_ops = &ram_aops; + inode->i_op = &configfs_inode_operations; + + if (sd->s_iattr) { + /* sysfs_dirent has non-default attributes + * get them for the new inode from persistent copy + * in sysfs_dirent + */ + set_inode_attr(inode, sd->s_iattr); + } else + set_default_inode_attr(inode, mode); + } + return inode; +} + +#ifdef CONFIG_LOCKDEP + +static void configfs_set_inode_lock_class(struct configfs_dirent *sd, + struct inode *inode) +{ + int depth = sd->s_depth; + + if (depth > 0) { + if (depth <= ARRAY_SIZE(default_group_class)) { + lockdep_set_class(&inode->i_rwsem, + &default_group_class[depth - 1]); + } else { + /* + * In practice the maximum level of locking depth is + * already reached. Just inform about possible reasons. + */ + pr_info("Too many levels of inodes for the locking correctness validator.\n"); + pr_info("Spurious warnings may appear.\n"); + } + } +} + +#else /* CONFIG_LOCKDEP */ + +static void configfs_set_inode_lock_class(struct configfs_dirent *sd, + struct inode *inode) +{ +} + +#endif /* CONFIG_LOCKDEP */ + +struct inode *configfs_create(struct dentry *dentry, umode_t mode) +{ + struct inode *inode = NULL; + struct configfs_dirent *sd; + struct inode *p_inode; + + if (!dentry) + return ERR_PTR(-ENOENT); + + if (d_really_is_positive(dentry)) + return ERR_PTR(-EEXIST); + + sd = dentry->d_fsdata; + inode = configfs_new_inode(mode, sd, dentry->d_sb); + if (!inode) + return ERR_PTR(-ENOMEM); + + p_inode = d_inode(dentry->d_parent); + p_inode->i_mtime = p_inode->i_ctime = current_time(p_inode); + configfs_set_inode_lock_class(sd, inode); + return inode; +} + +/* + * Get the name for corresponding element represented by the given configfs_dirent + */ +const unsigned char * configfs_get_name(struct configfs_dirent *sd) +{ + struct configfs_attribute *attr; + + BUG_ON(!sd || !sd->s_element); + + /* These always have a dentry, so use that */ + if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) + return sd->s_dentry->d_name.name; + + if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) { + attr = sd->s_element; + return attr->ca_name; + } + return NULL; +} + + +/* + * Unhashes the dentry corresponding to given configfs_dirent + * Called with parent inode's i_mutex held. + */ +void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) +{ + struct dentry * dentry = sd->s_dentry; + + if (dentry) { + spin_lock(&dentry->d_lock); + if (simple_positive(dentry)) { + dget_dlock(dentry); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + simple_unlink(d_inode(parent), dentry); + } else + spin_unlock(&dentry->d_lock); + } +} + +void configfs_hash_and_remove(struct dentry * dir, const char * name) +{ + struct configfs_dirent * sd; + struct configfs_dirent * parent_sd = dir->d_fsdata; + + if (d_really_is_negative(dir)) + /* no inode means this hasn't been made visible yet */ + return; + + inode_lock(d_inode(dir)); + list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { + if (!sd->s_element) + continue; + if (!strcmp(configfs_get_name(sd), name)) { + spin_lock(&configfs_dirent_lock); + list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); + configfs_drop_dentry(sd, dir); + configfs_put(sd); + break; + } + } + inode_unlock(d_inode(dir)); +} |