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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * inode.c - basic inode and dentry operations. | |
3 | * | |
4 | * sysfs is Copyright (c) 2001-3 Patrick Mochel | |
5 | * | |
6 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
7 | */ | |
8 | ||
9 | #undef DEBUG | |
10 | ||
11 | #include <linux/pagemap.h> | |
12 | #include <linux/namei.h> | |
13 | #include <linux/backing-dev.h> | |
14 | #include "sysfs.h" | |
15 | ||
16 | extern struct super_block * sysfs_sb; | |
17 | ||
18 | static struct address_space_operations sysfs_aops = { | |
19 | .readpage = simple_readpage, | |
20 | .prepare_write = simple_prepare_write, | |
21 | .commit_write = simple_commit_write | |
22 | }; | |
23 | ||
24 | static struct backing_dev_info sysfs_backing_dev_info = { | |
25 | .ra_pages = 0, /* No readahead */ | |
26 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
27 | }; | |
28 | ||
29 | struct inode * sysfs_new_inode(mode_t mode) | |
30 | { | |
31 | struct inode * inode = new_inode(sysfs_sb); | |
32 | if (inode) { | |
33 | inode->i_mode = mode; | |
34 | inode->i_uid = 0; | |
35 | inode->i_gid = 0; | |
36 | inode->i_blksize = PAGE_CACHE_SIZE; | |
37 | inode->i_blocks = 0; | |
38 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
39 | inode->i_mapping->a_ops = &sysfs_aops; | |
40 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
41 | } | |
42 | return inode; | |
43 | } | |
44 | ||
45 | int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
46 | { | |
47 | int error = 0; | |
48 | struct inode * inode = NULL; | |
49 | if (dentry) { | |
50 | if (!dentry->d_inode) { | |
51 | if ((inode = sysfs_new_inode(mode))) { | |
52 | if (dentry->d_parent && dentry->d_parent->d_inode) { | |
53 | struct inode *p_inode = dentry->d_parent->d_inode; | |
54 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
55 | } | |
56 | goto Proceed; | |
57 | } | |
58 | else | |
59 | error = -ENOMEM; | |
60 | } else | |
61 | error = -EEXIST; | |
62 | } else | |
63 | error = -ENOENT; | |
64 | goto Done; | |
65 | ||
66 | Proceed: | |
67 | if (init) | |
68 | error = init(inode); | |
69 | if (!error) { | |
70 | d_instantiate(dentry, inode); | |
71 | if (S_ISDIR(mode)) | |
72 | dget(dentry); /* pin only directory dentry in core */ | |
73 | } else | |
74 | iput(inode); | |
75 | Done: | |
76 | return error; | |
77 | } | |
78 | ||
79 | struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name) | |
80 | { | |
81 | struct qstr qstr; | |
82 | ||
83 | qstr.name = name; | |
84 | qstr.len = strlen(name); | |
85 | qstr.hash = full_name_hash(name,qstr.len); | |
86 | return lookup_hash(&qstr,parent); | |
87 | } | |
88 | ||
89 | /* | |
90 | * Get the name for corresponding element represented by the given sysfs_dirent | |
91 | */ | |
92 | const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) | |
93 | { | |
94 | struct attribute * attr; | |
95 | struct bin_attribute * bin_attr; | |
96 | struct sysfs_symlink * sl; | |
97 | ||
98 | if (!sd || !sd->s_element) | |
99 | BUG(); | |
100 | ||
101 | switch (sd->s_type) { | |
102 | case SYSFS_DIR: | |
103 | /* Always have a dentry so use that */ | |
104 | return sd->s_dentry->d_name.name; | |
105 | ||
106 | case SYSFS_KOBJ_ATTR: | |
107 | attr = sd->s_element; | |
108 | return attr->name; | |
109 | ||
110 | case SYSFS_KOBJ_BIN_ATTR: | |
111 | bin_attr = sd->s_element; | |
112 | return bin_attr->attr.name; | |
113 | ||
114 | case SYSFS_KOBJ_LINK: | |
115 | sl = sd->s_element; | |
116 | return sl->link_name; | |
117 | } | |
118 | return NULL; | |
119 | } | |
120 | ||
121 | ||
122 | /* | |
123 | * Unhashes the dentry corresponding to given sysfs_dirent | |
124 | * Called with parent inode's i_sem held. | |
125 | */ | |
126 | void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) | |
127 | { | |
128 | struct dentry * dentry = sd->s_dentry; | |
129 | ||
130 | if (dentry) { | |
131 | spin_lock(&dcache_lock); | |
132 | spin_lock(&dentry->d_lock); | |
133 | if (!(d_unhashed(dentry) && dentry->d_inode)) { | |
134 | dget_locked(dentry); | |
135 | __d_drop(dentry); | |
136 | spin_unlock(&dentry->d_lock); | |
137 | spin_unlock(&dcache_lock); | |
138 | simple_unlink(parent->d_inode, dentry); | |
139 | } else { | |
140 | spin_unlock(&dentry->d_lock); | |
141 | spin_unlock(&dcache_lock); | |
142 | } | |
143 | } | |
144 | } | |
145 | ||
146 | void sysfs_hash_and_remove(struct dentry * dir, const char * name) | |
147 | { | |
148 | struct sysfs_dirent * sd; | |
149 | struct sysfs_dirent * parent_sd = dir->d_fsdata; | |
150 | ||
151 | down(&dir->d_inode->i_sem); | |
152 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
153 | if (!sd->s_element) | |
154 | continue; | |
155 | if (!strcmp(sysfs_get_name(sd), name)) { | |
156 | list_del_init(&sd->s_sibling); | |
157 | sysfs_drop_dentry(sd, dir); | |
158 | sysfs_put(sd); | |
159 | break; | |
160 | } | |
161 | } | |
162 | up(&dir->d_inode->i_sem); | |
163 | } | |
164 | ||
165 |