diff options
Diffstat (limited to 'fs/sysfs/inode.c')
| -rw-r--r-- | fs/sysfs/inode.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c new file mode 100644 index 000000000000..aff7b2dfa8ee --- /dev/null +++ b/fs/sysfs/inode.c @@ -0,0 +1,165 @@ +/* + * 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 */ + .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, +}; + +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); + spin_lock(&dentry->d_lock); + if (!(d_unhashed(dentry) && dentry->d_inode)) { + dget_locked(dentry); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); + simple_unlink(parent->d_inode, dentry); + } else { + spin_unlock(&dentry->d_lock); + 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); +} + + |