2 * inode.c - basic inode and dentry operations.
4 * sysfs is Copyright (c) 2001-3 Patrick Mochel
6 * Please see Documentation/filesystems/sysfs.txt for more information.
11 #include <linux/pagemap.h>
12 #include <linux/namei.h>
13 #include <linux/backing-dev.h>
14 #include <linux/capability.h>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
19 extern struct super_block * sysfs_sb;
21 static const struct address_space_operations sysfs_aops = {
22 .readpage = simple_readpage,
23 .prepare_write = simple_prepare_write,
24 .commit_write = simple_commit_write
27 static struct backing_dev_info sysfs_backing_dev_info = {
28 .ra_pages = 0, /* No readahead */
29 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
32 static const struct inode_operations sysfs_inode_operations ={
33 .setattr = sysfs_setattr,
36 void sysfs_delete_inode(struct inode *inode)
38 /* Free the shadowed directory inode operations */
39 if (sysfs_is_shadowed_inode(inode)) {
43 return generic_delete_inode(inode);
46 int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
48 struct inode * inode = dentry->d_inode;
49 struct sysfs_dirent * sd = dentry->d_fsdata;
50 struct iattr * sd_iattr;
51 unsigned int ia_valid = iattr->ia_valid;
57 sd_iattr = sd->s_iattr;
59 error = inode_change_ok(inode, iattr);
63 error = inode_setattr(inode, iattr);
68 /* setting attributes for the first time, allocate now */
69 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
72 /* assign default attributes */
73 sd_iattr->ia_mode = sd->s_mode;
76 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
77 sd->s_iattr = sd_iattr;
80 /* attributes were changed atleast once in past */
82 if (ia_valid & ATTR_UID)
83 sd_iattr->ia_uid = iattr->ia_uid;
84 if (ia_valid & ATTR_GID)
85 sd_iattr->ia_gid = iattr->ia_gid;
86 if (ia_valid & ATTR_ATIME)
87 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
88 inode->i_sb->s_time_gran);
89 if (ia_valid & ATTR_MTIME)
90 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
91 inode->i_sb->s_time_gran);
92 if (ia_valid & ATTR_CTIME)
93 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
94 inode->i_sb->s_time_gran);
95 if (ia_valid & ATTR_MODE) {
96 umode_t mode = iattr->ia_mode;
98 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
100 sd_iattr->ia_mode = sd->s_mode = mode;
106 static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
108 inode->i_mode = mode;
111 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
114 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
116 inode->i_mode = iattr->ia_mode;
117 inode->i_uid = iattr->ia_uid;
118 inode->i_gid = iattr->ia_gid;
119 inode->i_atime = iattr->ia_atime;
120 inode->i_mtime = iattr->ia_mtime;
121 inode->i_ctime = iattr->ia_ctime;
126 * sysfs has a different i_mutex lock order behavior for i_mutex than other
127 * filesystems; sysfs i_mutex is called in many places with subsystem locks
128 * held. At the same time, many of the VFS locking rules do not apply to
129 * sysfs at all (cross directory rename for example). To untangle this mess
130 * (which gives false positives in lockdep), we're giving sysfs inodes their
131 * own class for i_mutex.
133 static struct lock_class_key sysfs_inode_imutex_key;
135 static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
138 inode->i_mapping->a_ops = &sysfs_aops;
139 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
140 inode->i_op = &sysfs_inode_operations;
141 inode->i_ino = sd->s_ino;
142 lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
145 /* sysfs_dirent has non-default attributes
146 * get them for the new inode from persistent copy
149 set_inode_attr(inode, sd->s_iattr);
151 set_default_inode_attr(inode, sd->s_mode);
155 * sysfs_get_inode - get inode for sysfs_dirent
156 * @sd: sysfs_dirent to allocate inode for
158 * Get inode for @sd. If such inode doesn't exist, a new inode
159 * is allocated and basics are initialized. New inode is
163 * Kernel thread context (may sleep).
166 * Pointer to allocated inode on success, NULL on failure.
168 struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
172 inode = iget_locked(sysfs_sb, sd->s_ino);
173 if (inode && (inode->i_state & I_NEW))
174 sysfs_init_inode(sd, inode);
180 * sysfs_instantiate - instantiate dentry
181 * @dentry: dentry to be instantiated
182 * @inode: inode associated with @sd
184 * Unlock @inode if locked and instantiate @dentry with @inode.
189 void sysfs_instantiate(struct dentry *dentry, struct inode *inode)
191 BUG_ON(!dentry || dentry->d_inode);
193 if (inode->i_state & I_NEW)
194 unlock_new_inode(inode);
196 d_instantiate(dentry, inode);
199 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
201 struct sysfs_addrm_cxt acxt;
202 struct sysfs_dirent **pos, *sd;
207 sysfs_addrm_start(&acxt, dir_sd);
209 for (pos = &dir_sd->s_children; *pos; pos = &(*pos)->s_sibling) {
214 if (!strcmp(sd->s_name, name)) {
215 *pos = sd->s_sibling;
216 sd->s_sibling = NULL;
217 sysfs_remove_one(&acxt, sd);
222 if (sysfs_addrm_finish(&acxt))