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7063fbf2 JB |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * inode.c - basic inode and dentry operations. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public | |
17 | * License along with this program; if not, write to the | |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | * Boston, MA 021110-1307, USA. | |
20 | * | |
21 | * Based on sysfs: | |
22 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
23 | * | |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | * | |
26 | * Please see Documentation/filesystems/configfs.txt for more information. | |
27 | */ | |
28 | ||
29 | #undef DEBUG | |
30 | ||
31 | #include <linux/pagemap.h> | |
32 | #include <linux/namei.h> | |
33 | #include <linux/backing-dev.h> | |
34 | ||
35 | #include <linux/configfs.h> | |
36 | #include "configfs_internal.h" | |
37 | ||
38 | extern struct super_block * configfs_sb; | |
39 | ||
40 | static struct address_space_operations configfs_aops = { | |
41 | .readpage = simple_readpage, | |
42 | .prepare_write = simple_prepare_write, | |
43 | .commit_write = simple_commit_write | |
44 | }; | |
45 | ||
46 | static struct backing_dev_info configfs_backing_dev_info = { | |
47 | .ra_pages = 0, /* No readahead */ | |
48 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
49 | }; | |
50 | ||
51 | struct inode * configfs_new_inode(mode_t mode) | |
52 | { | |
53 | struct inode * inode = new_inode(configfs_sb); | |
54 | if (inode) { | |
55 | inode->i_mode = mode; | |
56 | inode->i_uid = 0; | |
57 | inode->i_gid = 0; | |
58 | inode->i_blksize = PAGE_CACHE_SIZE; | |
59 | inode->i_blocks = 0; | |
60 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
61 | inode->i_mapping->a_ops = &configfs_aops; | |
62 | inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; | |
63 | } | |
64 | return inode; | |
65 | } | |
66 | ||
67 | int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
68 | { | |
69 | int error = 0; | |
70 | struct inode * inode = NULL; | |
71 | if (dentry) { | |
72 | if (!dentry->d_inode) { | |
73 | if ((inode = configfs_new_inode(mode))) { | |
74 | if (dentry->d_parent && dentry->d_parent->d_inode) { | |
75 | struct inode *p_inode = dentry->d_parent->d_inode; | |
76 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
77 | } | |
78 | goto Proceed; | |
79 | } | |
80 | else | |
81 | error = -ENOMEM; | |
82 | } else | |
83 | error = -EEXIST; | |
84 | } else | |
85 | error = -ENOENT; | |
86 | goto Done; | |
87 | ||
88 | Proceed: | |
89 | if (init) | |
90 | error = init(inode); | |
91 | if (!error) { | |
92 | d_instantiate(dentry, inode); | |
93 | if (S_ISDIR(mode) || S_ISLNK(mode)) | |
94 | dget(dentry); /* pin link and directory dentries in core */ | |
95 | } else | |
96 | iput(inode); | |
97 | Done: | |
98 | return error; | |
99 | } | |
100 | ||
101 | /* | |
102 | * Get the name for corresponding element represented by the given configfs_dirent | |
103 | */ | |
104 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
105 | { | |
106 | struct attribute * attr; | |
107 | ||
108 | if (!sd || !sd->s_element) | |
109 | BUG(); | |
110 | ||
111 | /* These always have a dentry, so use that */ | |
112 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
113 | return sd->s_dentry->d_name.name; | |
114 | ||
115 | if (sd->s_type & CONFIGFS_ITEM_ATTR) { | |
116 | attr = sd->s_element; | |
117 | return attr->name; | |
118 | } | |
119 | return NULL; | |
120 | } | |
121 | ||
122 | ||
123 | /* | |
124 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 125 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
126 | */ |
127 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
128 | { | |
129 | struct dentry * dentry = sd->s_dentry; | |
130 | ||
131 | if (dentry) { | |
132 | spin_lock(&dcache_lock); | |
133 | if (!(d_unhashed(dentry) && dentry->d_inode)) { | |
134 | dget_locked(dentry); | |
135 | __d_drop(dentry); | |
136 | spin_unlock(&dcache_lock); | |
137 | simple_unlink(parent->d_inode, dentry); | |
138 | } else | |
139 | spin_unlock(&dcache_lock); | |
140 | } | |
141 | } | |
142 | ||
143 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
144 | { | |
145 | struct configfs_dirent * sd; | |
146 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
147 | ||
1b1dcc1b | 148 | mutex_lock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
149 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
150 | if (!sd->s_element) | |
151 | continue; | |
152 | if (!strcmp(configfs_get_name(sd), name)) { | |
153 | list_del_init(&sd->s_sibling); | |
154 | configfs_drop_dentry(sd, dir); | |
155 | configfs_put(sd); | |
156 | break; | |
157 | } | |
158 | } | |
1b1dcc1b | 159 | mutex_unlock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
160 | } |
161 | ||
162 |