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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 | /* * inode.c - basic inode and dentry operations. * * sysfs is Copyright (c) 2001-3 Patrick Mochel * * Please see Documentation/filesystems/sysfs.txt for more information. */ #undef DEBUG #include <linux/pagemap.h> #include <linux/namei.h> #include <linux/backing-dev.h> #include "sysfs.h" extern struct super_block * sysfs_sb; static struct address_space_operations sysfs_aops = { .readpage = simple_readpage, .prepare_write = simple_prepare_write, .commit_write = simple_commit_write }; static struct backing_dev_info sysfs_backing_dev_info = { .ra_pages = 0, /* No readahead */ .memory_backed = 1, /* Does not contribute to dirty memory */ }; struct inode * sysfs_new_inode(mode_t mode) { struct inode * inode = new_inode(sysfs_sb); if (inode) { inode->i_mode = mode; inode->i_uid = 0; inode->i_gid = 0; inode->i_blksize = PAGE_CACHE_SIZE; inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_mapping->a_ops = &sysfs_aops; inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; } return inode; } int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) { int error = 0; struct inode * inode = NULL; if (dentry) { if (!dentry->d_inode) { if ((inode = sysfs_new_inode(mode))) { if (dentry->d_parent && dentry->d_parent->d_inode) { struct inode *p_inode = dentry->d_parent->d_inode; p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; } goto Proceed; } else error = -ENOMEM; } else error = -EEXIST; } else error = -ENOENT; goto Done; Proceed: if (init) error = init(inode); if (!error) { d_instantiate(dentry, inode); if (S_ISDIR(mode)) dget(dentry); /* pin only directory dentry in core */ } else iput(inode); Done: return error; } struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name) { struct qstr qstr; qstr.name = name; qstr.len = strlen(name); qstr.hash = full_name_hash(name,qstr.len); return lookup_hash(&qstr,parent); } /* * Get the name for corresponding element represented by the given sysfs_dirent */ const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) { struct attribute * attr; struct bin_attribute * bin_attr; struct sysfs_symlink * sl; if (!sd || !sd->s_element) BUG(); switch (sd->s_type) { case SYSFS_DIR: /* Always have a dentry so use that */ return sd->s_dentry->d_name.name; case SYSFS_KOBJ_ATTR: attr = sd->s_element; return attr->name; case SYSFS_KOBJ_BIN_ATTR: bin_attr = sd->s_element; return bin_attr->attr.name; case SYSFS_KOBJ_LINK: sl = sd->s_element; return sl->link_name; } return NULL; } /* * Unhashes the dentry corresponding to given sysfs_dirent * Called with parent inode's i_sem held. */ void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) { struct dentry * dentry = sd->s_dentry; if (dentry) { spin_lock(&dcache_lock); if (!(d_unhashed(dentry) && dentry->d_inode)) { dget_locked(dentry); __d_drop(dentry); spin_unlock(&dcache_lock); simple_unlink(parent->d_inode, dentry); } else spin_unlock(&dcache_lock); } } void sysfs_hash_and_remove(struct dentry * dir, const char * name) { struct sysfs_dirent * sd; struct sysfs_dirent * parent_sd = dir->d_fsdata; down(&dir->d_inode->i_sem); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (!sd->s_element) continue; if (!strcmp(sysfs_get_name(sd), name)) { list_del_init(&sd->s_sibling); sysfs_drop_dentry(sd, dir); sysfs_put(sd); break; } } up(&dir->d_inode->i_sem); } |