11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * fs/libfs.c 31da177e4SLinus Torvalds * Library for filesystems writers. 41da177e4SLinus Torvalds */ 51da177e4SLinus Torvalds 61da177e4SLinus Torvalds #include <linux/module.h> 71da177e4SLinus Torvalds #include <linux/pagemap.h> 81da177e4SLinus Torvalds #include <linux/mount.h> 91da177e4SLinus Torvalds #include <linux/vfs.h> 107cf34c76SIngo Molnar #include <linux/mutex.h> 117cf34c76SIngo Molnar 121da177e4SLinus Torvalds #include <asm/uaccess.h> 131da177e4SLinus Torvalds 141da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 151da177e4SLinus Torvalds struct kstat *stat) 161da177e4SLinus Torvalds { 171da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 181da177e4SLinus Torvalds generic_fillattr(inode, stat); 191da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 201da177e4SLinus Torvalds return 0; 211da177e4SLinus Torvalds } 221da177e4SLinus Torvalds 23726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 241da177e4SLinus Torvalds { 25726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 261da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 271da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 281da177e4SLinus Torvalds return 0; 291da177e4SLinus Torvalds } 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* 321da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 331da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 341da177e4SLinus Torvalds */ 351da177e4SLinus Torvalds static int simple_delete_dentry(struct dentry *dentry) 361da177e4SLinus Torvalds { 371da177e4SLinus Torvalds return 1; 381da177e4SLinus Torvalds } 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds /* 411da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 421da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 431da177e4SLinus Torvalds */ 441da177e4SLinus Torvalds struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 451da177e4SLinus Torvalds { 461da177e4SLinus Torvalds static struct dentry_operations simple_dentry_operations = { 471da177e4SLinus Torvalds .d_delete = simple_delete_dentry, 481da177e4SLinus Torvalds }; 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 511da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 521da177e4SLinus Torvalds dentry->d_op = &simple_dentry_operations; 531da177e4SLinus Torvalds d_add(dentry, NULL); 541da177e4SLinus Torvalds return NULL; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds int simple_sync_file(struct file * file, struct dentry *dentry, int datasync) 581da177e4SLinus Torvalds { 591da177e4SLinus Torvalds return 0; 601da177e4SLinus Torvalds } 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 631da177e4SLinus Torvalds { 641da177e4SLinus Torvalds static struct qstr cursor_name = {.len = 1, .name = "."}; 651da177e4SLinus Torvalds 660f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 691da177e4SLinus Torvalds } 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 721da177e4SLinus Torvalds { 731da177e4SLinus Torvalds dput(file->private_data); 741da177e4SLinus Torvalds return 0; 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) 781da177e4SLinus Torvalds { 790f7fc9e4SJosef "Jeff" Sipek mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 801da177e4SLinus Torvalds switch (origin) { 811da177e4SLinus Torvalds case 1: 821da177e4SLinus Torvalds offset += file->f_pos; 831da177e4SLinus Torvalds case 0: 841da177e4SLinus Torvalds if (offset >= 0) 851da177e4SLinus Torvalds break; 861da177e4SLinus Torvalds default: 870f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 881da177e4SLinus Torvalds return -EINVAL; 891da177e4SLinus Torvalds } 901da177e4SLinus Torvalds if (offset != file->f_pos) { 911da177e4SLinus Torvalds file->f_pos = offset; 921da177e4SLinus Torvalds if (file->f_pos >= 2) { 931da177e4SLinus Torvalds struct list_head *p; 941da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 951da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds spin_lock(&dcache_lock); 985160ee6fSEric Dumazet list_del(&cursor->d_u.d_child); 990f7fc9e4SJosef "Jeff" Sipek p = file->f_path.dentry->d_subdirs.next; 1000f7fc9e4SJosef "Jeff" Sipek while (n && p != &file->f_path.dentry->d_subdirs) { 1011da177e4SLinus Torvalds struct dentry *next; 1025160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1031da177e4SLinus Torvalds if (!d_unhashed(next) && next->d_inode) 1041da177e4SLinus Torvalds n--; 1051da177e4SLinus Torvalds p = p->next; 1061da177e4SLinus Torvalds } 1075160ee6fSEric Dumazet list_add_tail(&cursor->d_u.d_child, p); 1081da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1091da177e4SLinus Torvalds } 1101da177e4SLinus Torvalds } 1110f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 1121da177e4SLinus Torvalds return offset; 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds 1151da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1161da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1171da177e4SLinus Torvalds { 1181da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1191da177e4SLinus Torvalds } 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds /* 1221da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1231da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1241da177e4SLinus Torvalds * both impossible due to the lock on directory. 1251da177e4SLinus Torvalds */ 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) 1281da177e4SLinus Torvalds { 1290f7fc9e4SJosef "Jeff" Sipek struct dentry *dentry = filp->f_path.dentry; 1301da177e4SLinus Torvalds struct dentry *cursor = filp->private_data; 1315160ee6fSEric Dumazet struct list_head *p, *q = &cursor->d_u.d_child; 1321da177e4SLinus Torvalds ino_t ino; 1331da177e4SLinus Torvalds int i = filp->f_pos; 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds switch (i) { 1361da177e4SLinus Torvalds case 0: 1371da177e4SLinus Torvalds ino = dentry->d_inode->i_ino; 1381da177e4SLinus Torvalds if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 1391da177e4SLinus Torvalds break; 1401da177e4SLinus Torvalds filp->f_pos++; 1411da177e4SLinus Torvalds i++; 1421da177e4SLinus Torvalds /* fallthrough */ 1431da177e4SLinus Torvalds case 1: 1441da177e4SLinus Torvalds ino = parent_ino(dentry); 1451da177e4SLinus Torvalds if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1461da177e4SLinus Torvalds break; 1471da177e4SLinus Torvalds filp->f_pos++; 1481da177e4SLinus Torvalds i++; 1491da177e4SLinus Torvalds /* fallthrough */ 1501da177e4SLinus Torvalds default: 1511da177e4SLinus Torvalds spin_lock(&dcache_lock); 1521bfba4e8SAkinobu Mita if (filp->f_pos == 2) 1531bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1541bfba4e8SAkinobu Mita 1551da177e4SLinus Torvalds for (p=q->next; p != &dentry->d_subdirs; p=p->next) { 1561da177e4SLinus Torvalds struct dentry *next; 1575160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1581da177e4SLinus Torvalds if (d_unhashed(next) || !next->d_inode) 1591da177e4SLinus Torvalds continue; 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1621da177e4SLinus Torvalds if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0) 1631da177e4SLinus Torvalds return 0; 1641da177e4SLinus Torvalds spin_lock(&dcache_lock); 1651da177e4SLinus Torvalds /* next is still alive */ 1661bfba4e8SAkinobu Mita list_move(q, p); 1671da177e4SLinus Torvalds p = q; 1681da177e4SLinus Torvalds filp->f_pos++; 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1711da177e4SLinus Torvalds } 1721da177e4SLinus Torvalds return 0; 1731da177e4SLinus Torvalds } 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1761da177e4SLinus Torvalds { 1771da177e4SLinus Torvalds return -EISDIR; 1781da177e4SLinus Torvalds } 1791da177e4SLinus Torvalds 1804b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1811da177e4SLinus Torvalds .open = dcache_dir_open, 1821da177e4SLinus Torvalds .release = dcache_dir_close, 1831da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1841da177e4SLinus Torvalds .read = generic_read_dir, 1851da177e4SLinus Torvalds .readdir = dcache_readdir, 1868ae0b778SHugh Dickins .fsync = simple_sync_file, 1871da177e4SLinus Torvalds }; 1881da177e4SLinus Torvalds 18992e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 1901da177e4SLinus Torvalds .lookup = simple_lookup, 1911da177e4SLinus Torvalds }; 1921da177e4SLinus Torvalds 193759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 194759b9775SHugh Dickins .statfs = simple_statfs, 195759b9775SHugh Dickins }; 196759b9775SHugh Dickins 1971da177e4SLinus Torvalds /* 1981da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 1991da177e4SLinus Torvalds * will never be mountable) 2001da177e4SLinus Torvalds */ 201454e2398SDavid Howells int get_sb_pseudo(struct file_system_type *fs_type, char *name, 202ee9b6d61SJosef 'Jeff' Sipek const struct super_operations *ops, unsigned long magic, 203454e2398SDavid Howells struct vfsmount *mnt) 2041da177e4SLinus Torvalds { 2051da177e4SLinus Torvalds struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); 2061da177e4SLinus Torvalds struct dentry *dentry; 2071da177e4SLinus Torvalds struct inode *root; 2081da177e4SLinus Torvalds struct qstr d_name = {.name = name, .len = strlen(name)}; 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds if (IS_ERR(s)) 211454e2398SDavid Howells return PTR_ERR(s); 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds s->s_flags = MS_NOUSER; 2141da177e4SLinus Torvalds s->s_maxbytes = ~0ULL; 2151da177e4SLinus Torvalds s->s_blocksize = 1024; 2161da177e4SLinus Torvalds s->s_blocksize_bits = 10; 2171da177e4SLinus Torvalds s->s_magic = magic; 218759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2191da177e4SLinus Torvalds s->s_time_gran = 1; 2201da177e4SLinus Torvalds root = new_inode(s); 2211da177e4SLinus Torvalds if (!root) 2221da177e4SLinus Torvalds goto Enomem; 2231a1c9bb4SJeff Layton /* 2241a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2251a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2261a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2271a1c9bb4SJeff Layton */ 2281a1c9bb4SJeff Layton root->i_ino = 1; 2291da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2301da177e4SLinus Torvalds root->i_uid = root->i_gid = 0; 2311da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 2321da177e4SLinus Torvalds dentry = d_alloc(NULL, &d_name); 2331da177e4SLinus Torvalds if (!dentry) { 2341da177e4SLinus Torvalds iput(root); 2351da177e4SLinus Torvalds goto Enomem; 2361da177e4SLinus Torvalds } 2371da177e4SLinus Torvalds dentry->d_sb = s; 2381da177e4SLinus Torvalds dentry->d_parent = dentry; 2391da177e4SLinus Torvalds d_instantiate(dentry, root); 2401da177e4SLinus Torvalds s->s_root = dentry; 2411da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 242454e2398SDavid Howells return simple_set_mnt(mnt, s); 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds Enomem: 2451da177e4SLinus Torvalds up_write(&s->s_umount); 2461da177e4SLinus Torvalds deactivate_super(s); 247454e2398SDavid Howells return -ENOMEM; 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds 2501da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2511da177e4SLinus Torvalds { 2521da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2531da177e4SLinus Torvalds 2541da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 255d8c76e6fSDave Hansen inc_nlink(inode); 2561da177e4SLinus Torvalds atomic_inc(&inode->i_count); 2571da177e4SLinus Torvalds dget(dentry); 2581da177e4SLinus Torvalds d_instantiate(dentry, inode); 2591da177e4SLinus Torvalds return 0; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 2621da177e4SLinus Torvalds static inline int simple_positive(struct dentry *dentry) 2631da177e4SLinus Torvalds { 2641da177e4SLinus Torvalds return dentry->d_inode && !d_unhashed(dentry); 2651da177e4SLinus Torvalds } 2661da177e4SLinus Torvalds 2671da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2681da177e4SLinus Torvalds { 2691da177e4SLinus Torvalds struct dentry *child; 2701da177e4SLinus Torvalds int ret = 0; 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds spin_lock(&dcache_lock); 2735160ee6fSEric Dumazet list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) 2741da177e4SLinus Torvalds if (simple_positive(child)) 2751da177e4SLinus Torvalds goto out; 2761da177e4SLinus Torvalds ret = 1; 2771da177e4SLinus Torvalds out: 2781da177e4SLinus Torvalds spin_unlock(&dcache_lock); 2791da177e4SLinus Torvalds return ret; 2801da177e4SLinus Torvalds } 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 2831da177e4SLinus Torvalds { 2841da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2851da177e4SLinus Torvalds 2861da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 2879a53c3a7SDave Hansen drop_nlink(inode); 2881da177e4SLinus Torvalds dput(dentry); 2891da177e4SLinus Torvalds return 0; 2901da177e4SLinus Torvalds } 2911da177e4SLinus Torvalds 2921da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 2931da177e4SLinus Torvalds { 2941da177e4SLinus Torvalds if (!simple_empty(dentry)) 2951da177e4SLinus Torvalds return -ENOTEMPTY; 2961da177e4SLinus Torvalds 2979a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 2981da177e4SLinus Torvalds simple_unlink(dir, dentry); 2999a53c3a7SDave Hansen drop_nlink(dir); 3001da177e4SLinus Torvalds return 0; 3011da177e4SLinus Torvalds } 3021da177e4SLinus Torvalds 3031da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3041da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3051da177e4SLinus Torvalds { 3061da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3071da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3101da177e4SLinus Torvalds return -ENOTEMPTY; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds if (new_dentry->d_inode) { 3131da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 3141da177e4SLinus Torvalds if (they_are_dirs) 3159a53c3a7SDave Hansen drop_nlink(old_dir); 3161da177e4SLinus Torvalds } else if (they_are_dirs) { 3179a53c3a7SDave Hansen drop_nlink(old_dir); 318d8c76e6fSDave Hansen inc_nlink(new_dir); 3191da177e4SLinus Torvalds } 3201da177e4SLinus Torvalds 3211da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3221da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3231da177e4SLinus Torvalds 3241da177e4SLinus Torvalds return 0; 3251da177e4SLinus Torvalds } 3261da177e4SLinus Torvalds 3271da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3281da177e4SLinus Torvalds { 329c0d92cbcSPekka J Enberg clear_highpage(page); 3301da177e4SLinus Torvalds flush_dcache_page(page); 3311da177e4SLinus Torvalds SetPageUptodate(page); 3321da177e4SLinus Torvalds unlock_page(page); 3331da177e4SLinus Torvalds return 0; 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds 3361da177e4SLinus Torvalds int simple_prepare_write(struct file *file, struct page *page, 3371da177e4SLinus Torvalds unsigned from, unsigned to) 3381da177e4SLinus Torvalds { 3391da177e4SLinus Torvalds if (!PageUptodate(page)) { 3401da177e4SLinus Torvalds if (to - from != PAGE_CACHE_SIZE) { 3411da177e4SLinus Torvalds void *kaddr = kmap_atomic(page, KM_USER0); 3421da177e4SLinus Torvalds memset(kaddr, 0, from); 3431da177e4SLinus Torvalds memset(kaddr + to, 0, PAGE_CACHE_SIZE - to); 3441da177e4SLinus Torvalds flush_dcache_page(page); 3451da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 3461da177e4SLinus Torvalds } 3471da177e4SLinus Torvalds } 3481da177e4SLinus Torvalds return 0; 3491da177e4SLinus Torvalds } 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds int simple_commit_write(struct file *file, struct page *page, 352955eff5aSNick Piggin unsigned from, unsigned to) 3531da177e4SLinus Torvalds { 3541da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 3551da177e4SLinus Torvalds loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; 3561da177e4SLinus Torvalds 357955eff5aSNick Piggin if (!PageUptodate(page)) 358955eff5aSNick Piggin SetPageUptodate(page); 3591da177e4SLinus Torvalds /* 3601da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 3611b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 3621da177e4SLinus Torvalds */ 3631da177e4SLinus Torvalds if (pos > inode->i_size) 3641da177e4SLinus Torvalds i_size_write(inode, pos); 3651da177e4SLinus Torvalds set_page_dirty(page); 3661da177e4SLinus Torvalds return 0; 3671da177e4SLinus Torvalds } 3681da177e4SLinus Torvalds 3691a1c9bb4SJeff Layton /* 3701a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 3711a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 3721a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 3731a1c9bb4SJeff Layton */ 3741da177e4SLinus Torvalds int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) 3751da177e4SLinus Torvalds { 3761da177e4SLinus Torvalds struct inode *inode; 3771da177e4SLinus Torvalds struct dentry *root; 3781da177e4SLinus Torvalds struct dentry *dentry; 3791da177e4SLinus Torvalds int i; 3801da177e4SLinus Torvalds 3811da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 3821da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 3831da177e4SLinus Torvalds s->s_magic = magic; 384759b9775SHugh Dickins s->s_op = &simple_super_operations; 3851da177e4SLinus Torvalds s->s_time_gran = 1; 3861da177e4SLinus Torvalds 3871da177e4SLinus Torvalds inode = new_inode(s); 3881da177e4SLinus Torvalds if (!inode) 3891da177e4SLinus Torvalds return -ENOMEM; 3901a1c9bb4SJeff Layton /* 3911a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 3921a1c9bb4SJeff Layton * entry at index 1 3931a1c9bb4SJeff Layton */ 3941a1c9bb4SJeff Layton inode->i_ino = 1; 3951da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 3961da177e4SLinus Torvalds inode->i_uid = inode->i_gid = 0; 3971da177e4SLinus Torvalds inode->i_blocks = 0; 3981da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 3991da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4001da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 4017656f328SVincent Hanquez inode->i_nlink = 2; 4021da177e4SLinus Torvalds root = d_alloc_root(inode); 4031da177e4SLinus Torvalds if (!root) { 4041da177e4SLinus Torvalds iput(inode); 4051da177e4SLinus Torvalds return -ENOMEM; 4061da177e4SLinus Torvalds } 4071da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 4081da177e4SLinus Torvalds if (!files->name) 4091da177e4SLinus Torvalds continue; 4101a1c9bb4SJeff Layton 4111a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 4121a1c9bb4SJeff Layton if (unlikely(i == 1)) 4131a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 4141a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 4151a1c9bb4SJeff Layton s->s_type->name); 4161a1c9bb4SJeff Layton 4171da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 4181da177e4SLinus Torvalds if (!dentry) 4191da177e4SLinus Torvalds goto out; 4201da177e4SLinus Torvalds inode = new_inode(s); 4211da177e4SLinus Torvalds if (!inode) 4221da177e4SLinus Torvalds goto out; 4231da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 4241da177e4SLinus Torvalds inode->i_uid = inode->i_gid = 0; 4251da177e4SLinus Torvalds inode->i_blocks = 0; 4261da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4271da177e4SLinus Torvalds inode->i_fop = files->ops; 4281da177e4SLinus Torvalds inode->i_ino = i; 4291da177e4SLinus Torvalds d_add(dentry, inode); 4301da177e4SLinus Torvalds } 4311da177e4SLinus Torvalds s->s_root = root; 4321da177e4SLinus Torvalds return 0; 4331da177e4SLinus Torvalds out: 4341da177e4SLinus Torvalds d_genocide(root); 4351da177e4SLinus Torvalds dput(root); 4361da177e4SLinus Torvalds return -ENOMEM; 4371da177e4SLinus Torvalds } 4381da177e4SLinus Torvalds 4391da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 4401da177e4SLinus Torvalds 4411f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 4421da177e4SLinus Torvalds { 4431da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 4441da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 4451da177e4SLinus Torvalds if (unlikely(!*mount)) { 4461da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 4471f5ce9e9STrond Myklebust mnt = vfs_kern_mount(type, 0, type->name, NULL); 4481da177e4SLinus Torvalds if (IS_ERR(mnt)) 4491da177e4SLinus Torvalds return PTR_ERR(mnt); 4501da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 4511da177e4SLinus Torvalds if (!*mount) 4521da177e4SLinus Torvalds *mount = mnt; 4531da177e4SLinus Torvalds } 4541da177e4SLinus Torvalds mntget(*mount); 4551da177e4SLinus Torvalds ++*count; 4561da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 4571da177e4SLinus Torvalds mntput(mnt); 4581da177e4SLinus Torvalds return 0; 4591da177e4SLinus Torvalds } 4601da177e4SLinus Torvalds 4611da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 4621da177e4SLinus Torvalds { 4631da177e4SLinus Torvalds struct vfsmount *mnt; 4641da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 4651da177e4SLinus Torvalds mnt = *mount; 4661da177e4SLinus Torvalds if (!--*count) 4671da177e4SLinus Torvalds *mount = NULL; 4681da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 4691da177e4SLinus Torvalds mntput(mnt); 4701da177e4SLinus Torvalds } 4711da177e4SLinus Torvalds 4721da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 4731da177e4SLinus Torvalds const void *from, size_t available) 4741da177e4SLinus Torvalds { 4751da177e4SLinus Torvalds loff_t pos = *ppos; 4761da177e4SLinus Torvalds if (pos < 0) 4771da177e4SLinus Torvalds return -EINVAL; 4781da177e4SLinus Torvalds if (pos >= available) 4791da177e4SLinus Torvalds return 0; 4801da177e4SLinus Torvalds if (count > available - pos) 4811da177e4SLinus Torvalds count = available - pos; 4821da177e4SLinus Torvalds if (copy_to_user(to, from + pos, count)) 4831da177e4SLinus Torvalds return -EFAULT; 4841da177e4SLinus Torvalds *ppos = pos + count; 4851da177e4SLinus Torvalds return count; 4861da177e4SLinus Torvalds } 4871da177e4SLinus Torvalds 4881da177e4SLinus Torvalds /* 4891da177e4SLinus Torvalds * Transaction based IO. 4901da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 4911da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 4921da177e4SLinus Torvalds * file-local buffer. 4931da177e4SLinus Torvalds */ 4941da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 4951da177e4SLinus Torvalds { 4961da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 4971da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 5001da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 5011da177e4SLinus Torvalds 5021da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 5031da177e4SLinus Torvalds if (!ar) 5041da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 5071da177e4SLinus Torvalds 5081da177e4SLinus Torvalds /* only one write allowed per open */ 5091da177e4SLinus Torvalds if (file->private_data) { 5101da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 5111da177e4SLinus Torvalds free_page((unsigned long)ar); 5121da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 5131da177e4SLinus Torvalds } 5141da177e4SLinus Torvalds 5151da177e4SLinus Torvalds file->private_data = ar; 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 5181da177e4SLinus Torvalds 5191da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 5201da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 5211da177e4SLinus Torvalds 5221da177e4SLinus Torvalds return ar->data; 5231da177e4SLinus Torvalds } 5241da177e4SLinus Torvalds 5251da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 5261da177e4SLinus Torvalds { 5271da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 5281da177e4SLinus Torvalds 5291da177e4SLinus Torvalds if (!ar) 5301da177e4SLinus Torvalds return 0; 5311da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 5321da177e4SLinus Torvalds } 5331da177e4SLinus Torvalds 5341da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 5351da177e4SLinus Torvalds { 5361da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 5371da177e4SLinus Torvalds return 0; 5381da177e4SLinus Torvalds } 5391da177e4SLinus Torvalds 540acaefc25SArnd Bergmann /* Simple attribute files */ 541acaefc25SArnd Bergmann 542acaefc25SArnd Bergmann struct simple_attr { 543acaefc25SArnd Bergmann u64 (*get)(void *); 544acaefc25SArnd Bergmann void (*set)(void *, u64); 545acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 546acaefc25SArnd Bergmann char set_buf[24]; 547acaefc25SArnd Bergmann void *data; 548acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 5497cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 550acaefc25SArnd Bergmann }; 551acaefc25SArnd Bergmann 552acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 553acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 554acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 555acaefc25SArnd Bergmann u64 (*get)(void *), void (*set)(void *, u64), 556acaefc25SArnd Bergmann const char *fmt) 557acaefc25SArnd Bergmann { 558acaefc25SArnd Bergmann struct simple_attr *attr; 559acaefc25SArnd Bergmann 560acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 561acaefc25SArnd Bergmann if (!attr) 562acaefc25SArnd Bergmann return -ENOMEM; 563acaefc25SArnd Bergmann 564acaefc25SArnd Bergmann attr->get = get; 565acaefc25SArnd Bergmann attr->set = set; 5668e18e294STheodore Ts'o attr->data = inode->i_private; 567acaefc25SArnd Bergmann attr->fmt = fmt; 5687cf34c76SIngo Molnar mutex_init(&attr->mutex); 569acaefc25SArnd Bergmann 570acaefc25SArnd Bergmann file->private_data = attr; 571acaefc25SArnd Bergmann 572acaefc25SArnd Bergmann return nonseekable_open(inode, file); 573acaefc25SArnd Bergmann } 574acaefc25SArnd Bergmann 575acaefc25SArnd Bergmann int simple_attr_close(struct inode *inode, struct file *file) 576acaefc25SArnd Bergmann { 577acaefc25SArnd Bergmann kfree(file->private_data); 578acaefc25SArnd Bergmann return 0; 579acaefc25SArnd Bergmann } 580acaefc25SArnd Bergmann 581acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 582acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 583acaefc25SArnd Bergmann size_t len, loff_t *ppos) 584acaefc25SArnd Bergmann { 585acaefc25SArnd Bergmann struct simple_attr *attr; 586acaefc25SArnd Bergmann size_t size; 587acaefc25SArnd Bergmann ssize_t ret; 588acaefc25SArnd Bergmann 589acaefc25SArnd Bergmann attr = file->private_data; 590acaefc25SArnd Bergmann 591acaefc25SArnd Bergmann if (!attr->get) 592acaefc25SArnd Bergmann return -EACCES; 593acaefc25SArnd Bergmann 5947cf34c76SIngo Molnar mutex_lock(&attr->mutex); 595acaefc25SArnd Bergmann if (*ppos) /* continued read */ 596acaefc25SArnd Bergmann size = strlen(attr->get_buf); 597acaefc25SArnd Bergmann else /* first read */ 598acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 599acaefc25SArnd Bergmann attr->fmt, 600acaefc25SArnd Bergmann (unsigned long long)attr->get(attr->data)); 601acaefc25SArnd Bergmann 602acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 6037cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 604acaefc25SArnd Bergmann return ret; 605acaefc25SArnd Bergmann } 606acaefc25SArnd Bergmann 607acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 608acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 609acaefc25SArnd Bergmann size_t len, loff_t *ppos) 610acaefc25SArnd Bergmann { 611acaefc25SArnd Bergmann struct simple_attr *attr; 612acaefc25SArnd Bergmann u64 val; 613acaefc25SArnd Bergmann size_t size; 614acaefc25SArnd Bergmann ssize_t ret; 615acaefc25SArnd Bergmann 616acaefc25SArnd Bergmann attr = file->private_data; 617acaefc25SArnd Bergmann 618acaefc25SArnd Bergmann if (!attr->set) 619acaefc25SArnd Bergmann return -EACCES; 620acaefc25SArnd Bergmann 6217cf34c76SIngo Molnar mutex_lock(&attr->mutex); 622acaefc25SArnd Bergmann ret = -EFAULT; 623acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 624acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 625acaefc25SArnd Bergmann goto out; 626acaefc25SArnd Bergmann 627acaefc25SArnd Bergmann ret = len; /* claim we got the whole input */ 628acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 629acaefc25SArnd Bergmann val = simple_strtol(attr->set_buf, NULL, 0); 630acaefc25SArnd Bergmann attr->set(attr->data, val); 631acaefc25SArnd Bergmann out: 6327cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 633acaefc25SArnd Bergmann return ret; 634acaefc25SArnd Bergmann } 635acaefc25SArnd Bergmann 6361da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_close); 6371da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_lseek); 6381da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_open); 6391da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_readdir); 6401da177e4SLinus Torvalds EXPORT_SYMBOL(generic_read_dir); 6411da177e4SLinus Torvalds EXPORT_SYMBOL(get_sb_pseudo); 6421da177e4SLinus Torvalds EXPORT_SYMBOL(simple_commit_write); 6431da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_inode_operations); 6441da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_operations); 6451da177e4SLinus Torvalds EXPORT_SYMBOL(simple_empty); 6461da177e4SLinus Torvalds EXPORT_SYMBOL(d_alloc_name); 6471da177e4SLinus Torvalds EXPORT_SYMBOL(simple_fill_super); 6481da177e4SLinus Torvalds EXPORT_SYMBOL(simple_getattr); 6491da177e4SLinus Torvalds EXPORT_SYMBOL(simple_link); 6501da177e4SLinus Torvalds EXPORT_SYMBOL(simple_lookup); 6511da177e4SLinus Torvalds EXPORT_SYMBOL(simple_pin_fs); 6521da177e4SLinus Torvalds EXPORT_SYMBOL(simple_prepare_write); 6531da177e4SLinus Torvalds EXPORT_SYMBOL(simple_readpage); 6541da177e4SLinus Torvalds EXPORT_SYMBOL(simple_release_fs); 6551da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rename); 6561da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rmdir); 6571da177e4SLinus Torvalds EXPORT_SYMBOL(simple_statfs); 6581da177e4SLinus Torvalds EXPORT_SYMBOL(simple_sync_file); 6591da177e4SLinus Torvalds EXPORT_SYMBOL(simple_unlink); 6601da177e4SLinus Torvalds EXPORT_SYMBOL(simple_read_from_buffer); 6611da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_get); 6621da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_read); 6631da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_release); 664acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_open); 665acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_close); 666acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_read); 667acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_write); 668