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> 112596110aSChristoph Hellwig #include <linux/exportfs.h> 12d5aacad5SAl Viro #include <linux/writeback.h> 13d5aacad5SAl Viro #include <linux/buffer_head.h> 147cf34c76SIngo Molnar 151da177e4SLinus Torvalds #include <asm/uaccess.h> 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 181da177e4SLinus Torvalds struct kstat *stat) 191da177e4SLinus Torvalds { 201da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 211da177e4SLinus Torvalds generic_fillattr(inode, stat); 221da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 231da177e4SLinus Torvalds return 0; 241da177e4SLinus Torvalds } 251da177e4SLinus Torvalds 26726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 271da177e4SLinus Torvalds { 28726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 291da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 301da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 311da177e4SLinus Torvalds return 0; 321da177e4SLinus Torvalds } 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds /* 351da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 361da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 371da177e4SLinus Torvalds */ 381da177e4SLinus Torvalds static int simple_delete_dentry(struct dentry *dentry) 391da177e4SLinus Torvalds { 401da177e4SLinus Torvalds return 1; 411da177e4SLinus Torvalds } 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds /* 441da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 451da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 461da177e4SLinus Torvalds */ 471da177e4SLinus Torvalds struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 481da177e4SLinus Torvalds { 493ba13d17SAl Viro static const struct dentry_operations simple_dentry_operations = { 501da177e4SLinus Torvalds .d_delete = simple_delete_dentry, 511da177e4SLinus Torvalds }; 521da177e4SLinus Torvalds 531da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 541da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 551da177e4SLinus Torvalds dentry->d_op = &simple_dentry_operations; 561da177e4SLinus Torvalds d_add(dentry, NULL); 571da177e4SLinus Torvalds return NULL; 581da177e4SLinus Torvalds } 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds int simple_sync_file(struct file * file, struct dentry *dentry, int datasync) 611da177e4SLinus Torvalds { 621da177e4SLinus Torvalds return 0; 631da177e4SLinus Torvalds } 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 661da177e4SLinus Torvalds { 671da177e4SLinus Torvalds static struct qstr cursor_name = {.len = 1, .name = "."}; 681da177e4SLinus Torvalds 690f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 751da177e4SLinus Torvalds { 761da177e4SLinus Torvalds dput(file->private_data); 771da177e4SLinus Torvalds return 0; 781da177e4SLinus Torvalds } 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) 811da177e4SLinus Torvalds { 820f7fc9e4SJosef "Jeff" Sipek mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 831da177e4SLinus Torvalds switch (origin) { 841da177e4SLinus Torvalds case 1: 851da177e4SLinus Torvalds offset += file->f_pos; 861da177e4SLinus Torvalds case 0: 871da177e4SLinus Torvalds if (offset >= 0) 881da177e4SLinus Torvalds break; 891da177e4SLinus Torvalds default: 900f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 911da177e4SLinus Torvalds return -EINVAL; 921da177e4SLinus Torvalds } 931da177e4SLinus Torvalds if (offset != file->f_pos) { 941da177e4SLinus Torvalds file->f_pos = offset; 951da177e4SLinus Torvalds if (file->f_pos >= 2) { 961da177e4SLinus Torvalds struct list_head *p; 971da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 981da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds spin_lock(&dcache_lock); 1015160ee6fSEric Dumazet list_del(&cursor->d_u.d_child); 1020f7fc9e4SJosef "Jeff" Sipek p = file->f_path.dentry->d_subdirs.next; 1030f7fc9e4SJosef "Jeff" Sipek while (n && p != &file->f_path.dentry->d_subdirs) { 1041da177e4SLinus Torvalds struct dentry *next; 1055160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1061da177e4SLinus Torvalds if (!d_unhashed(next) && next->d_inode) 1071da177e4SLinus Torvalds n--; 1081da177e4SLinus Torvalds p = p->next; 1091da177e4SLinus Torvalds } 1105160ee6fSEric Dumazet list_add_tail(&cursor->d_u.d_child, p); 1111da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1121da177e4SLinus Torvalds } 1131da177e4SLinus Torvalds } 1140f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 1151da177e4SLinus Torvalds return offset; 1161da177e4SLinus Torvalds } 1171da177e4SLinus Torvalds 1181da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1191da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1201da177e4SLinus Torvalds { 1211da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1221da177e4SLinus Torvalds } 1231da177e4SLinus Torvalds 1241da177e4SLinus Torvalds /* 1251da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1261da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1271da177e4SLinus Torvalds * both impossible due to the lock on directory. 1281da177e4SLinus Torvalds */ 1291da177e4SLinus Torvalds 1301da177e4SLinus Torvalds int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) 1311da177e4SLinus Torvalds { 1320f7fc9e4SJosef "Jeff" Sipek struct dentry *dentry = filp->f_path.dentry; 1331da177e4SLinus Torvalds struct dentry *cursor = filp->private_data; 1345160ee6fSEric Dumazet struct list_head *p, *q = &cursor->d_u.d_child; 1351da177e4SLinus Torvalds ino_t ino; 1361da177e4SLinus Torvalds int i = filp->f_pos; 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds switch (i) { 1391da177e4SLinus Torvalds case 0: 1401da177e4SLinus Torvalds ino = dentry->d_inode->i_ino; 1411da177e4SLinus Torvalds if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 1421da177e4SLinus Torvalds break; 1431da177e4SLinus Torvalds filp->f_pos++; 1441da177e4SLinus Torvalds i++; 1451da177e4SLinus Torvalds /* fallthrough */ 1461da177e4SLinus Torvalds case 1: 1471da177e4SLinus Torvalds ino = parent_ino(dentry); 1481da177e4SLinus Torvalds if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1491da177e4SLinus Torvalds break; 1501da177e4SLinus Torvalds filp->f_pos++; 1511da177e4SLinus Torvalds i++; 1521da177e4SLinus Torvalds /* fallthrough */ 1531da177e4SLinus Torvalds default: 1541da177e4SLinus Torvalds spin_lock(&dcache_lock); 1551bfba4e8SAkinobu Mita if (filp->f_pos == 2) 1561bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1571bfba4e8SAkinobu Mita 1581da177e4SLinus Torvalds for (p=q->next; p != &dentry->d_subdirs; p=p->next) { 1591da177e4SLinus Torvalds struct dentry *next; 1605160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1611da177e4SLinus Torvalds if (d_unhashed(next) || !next->d_inode) 1621da177e4SLinus Torvalds continue; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1650f8952c2SRonni Nielsen if (filldir(dirent, next->d_name.name, 1660f8952c2SRonni Nielsen next->d_name.len, filp->f_pos, 1670f8952c2SRonni Nielsen next->d_inode->i_ino, 1680f8952c2SRonni Nielsen dt_type(next->d_inode)) < 0) 1691da177e4SLinus Torvalds return 0; 1701da177e4SLinus Torvalds spin_lock(&dcache_lock); 1711da177e4SLinus Torvalds /* next is still alive */ 1721bfba4e8SAkinobu Mita list_move(q, p); 1731da177e4SLinus Torvalds p = q; 1741da177e4SLinus Torvalds filp->f_pos++; 1751da177e4SLinus Torvalds } 1761da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1771da177e4SLinus Torvalds } 1781da177e4SLinus Torvalds return 0; 1791da177e4SLinus Torvalds } 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1821da177e4SLinus Torvalds { 1831da177e4SLinus Torvalds return -EISDIR; 1841da177e4SLinus Torvalds } 1851da177e4SLinus Torvalds 1864b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1871da177e4SLinus Torvalds .open = dcache_dir_open, 1881da177e4SLinus Torvalds .release = dcache_dir_close, 1891da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1901da177e4SLinus Torvalds .read = generic_read_dir, 1911da177e4SLinus Torvalds .readdir = dcache_readdir, 1928ae0b778SHugh Dickins .fsync = simple_sync_file, 1931da177e4SLinus Torvalds }; 1941da177e4SLinus Torvalds 19592e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 1961da177e4SLinus Torvalds .lookup = simple_lookup, 1971da177e4SLinus Torvalds }; 1981da177e4SLinus Torvalds 199759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 200759b9775SHugh Dickins .statfs = simple_statfs, 201759b9775SHugh Dickins }; 202759b9775SHugh Dickins 2031da177e4SLinus Torvalds /* 2041da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 2051da177e4SLinus Torvalds * will never be mountable) 2061da177e4SLinus Torvalds */ 207454e2398SDavid Howells int get_sb_pseudo(struct file_system_type *fs_type, char *name, 208ee9b6d61SJosef 'Jeff' Sipek const struct super_operations *ops, unsigned long magic, 209454e2398SDavid Howells struct vfsmount *mnt) 2101da177e4SLinus Torvalds { 2111da177e4SLinus Torvalds struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); 2121da177e4SLinus Torvalds struct dentry *dentry; 2131da177e4SLinus Torvalds struct inode *root; 2141da177e4SLinus Torvalds struct qstr d_name = {.name = name, .len = strlen(name)}; 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvalds if (IS_ERR(s)) 217454e2398SDavid Howells return PTR_ERR(s); 2181da177e4SLinus Torvalds 2191da177e4SLinus Torvalds s->s_flags = MS_NOUSER; 22089a4eb4bSJeff Layton s->s_maxbytes = MAX_LFS_FILESIZE; 2213971e1a9SAlex Nixon s->s_blocksize = PAGE_SIZE; 2223971e1a9SAlex Nixon s->s_blocksize_bits = PAGE_SHIFT; 2231da177e4SLinus Torvalds s->s_magic = magic; 224759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2251da177e4SLinus Torvalds s->s_time_gran = 1; 2261da177e4SLinus Torvalds root = new_inode(s); 2271da177e4SLinus Torvalds if (!root) 2281da177e4SLinus Torvalds goto Enomem; 2291a1c9bb4SJeff Layton /* 2301a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2311a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2321a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2331a1c9bb4SJeff Layton */ 2341a1c9bb4SJeff Layton root->i_ino = 1; 2351da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2361da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 2371da177e4SLinus Torvalds dentry = d_alloc(NULL, &d_name); 2381da177e4SLinus Torvalds if (!dentry) { 2391da177e4SLinus Torvalds iput(root); 2401da177e4SLinus Torvalds goto Enomem; 2411da177e4SLinus Torvalds } 2421da177e4SLinus Torvalds dentry->d_sb = s; 2431da177e4SLinus Torvalds dentry->d_parent = dentry; 2441da177e4SLinus Torvalds d_instantiate(dentry, root); 2451da177e4SLinus Torvalds s->s_root = dentry; 2461da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 247a3ec947cSSukadev Bhattiprolu simple_set_mnt(mnt, s); 248a3ec947cSSukadev Bhattiprolu return 0; 2491da177e4SLinus Torvalds 2501da177e4SLinus Torvalds Enomem: 2516f5bbff9SAl Viro deactivate_locked_super(s); 252454e2398SDavid Howells return -ENOMEM; 2531da177e4SLinus Torvalds } 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2561da177e4SLinus Torvalds { 2571da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2581da177e4SLinus Torvalds 2591da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 260d8c76e6fSDave Hansen inc_nlink(inode); 2611da177e4SLinus Torvalds atomic_inc(&inode->i_count); 2621da177e4SLinus Torvalds dget(dentry); 2631da177e4SLinus Torvalds d_instantiate(dentry, inode); 2641da177e4SLinus Torvalds return 0; 2651da177e4SLinus Torvalds } 2661da177e4SLinus Torvalds 2671da177e4SLinus Torvalds static inline int simple_positive(struct dentry *dentry) 2681da177e4SLinus Torvalds { 2691da177e4SLinus Torvalds return dentry->d_inode && !d_unhashed(dentry); 2701da177e4SLinus Torvalds } 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2731da177e4SLinus Torvalds { 2741da177e4SLinus Torvalds struct dentry *child; 2751da177e4SLinus Torvalds int ret = 0; 2761da177e4SLinus Torvalds 2771da177e4SLinus Torvalds spin_lock(&dcache_lock); 2785160ee6fSEric Dumazet list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) 2791da177e4SLinus Torvalds if (simple_positive(child)) 2801da177e4SLinus Torvalds goto out; 2811da177e4SLinus Torvalds ret = 1; 2821da177e4SLinus Torvalds out: 2831da177e4SLinus Torvalds spin_unlock(&dcache_lock); 2841da177e4SLinus Torvalds return ret; 2851da177e4SLinus Torvalds } 2861da177e4SLinus Torvalds 2871da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 2881da177e4SLinus Torvalds { 2891da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2901da177e4SLinus Torvalds 2911da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 2929a53c3a7SDave Hansen drop_nlink(inode); 2931da177e4SLinus Torvalds dput(dentry); 2941da177e4SLinus Torvalds return 0; 2951da177e4SLinus Torvalds } 2961da177e4SLinus Torvalds 2971da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 2981da177e4SLinus Torvalds { 2991da177e4SLinus Torvalds if (!simple_empty(dentry)) 3001da177e4SLinus Torvalds return -ENOTEMPTY; 3011da177e4SLinus Torvalds 3029a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 3031da177e4SLinus Torvalds simple_unlink(dir, dentry); 3049a53c3a7SDave Hansen drop_nlink(dir); 3051da177e4SLinus Torvalds return 0; 3061da177e4SLinus Torvalds } 3071da177e4SLinus Torvalds 3081da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3091da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3101da177e4SLinus Torvalds { 3111da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3121da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3151da177e4SLinus Torvalds return -ENOTEMPTY; 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds if (new_dentry->d_inode) { 3181da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 3191da177e4SLinus Torvalds if (they_are_dirs) 3209a53c3a7SDave Hansen drop_nlink(old_dir); 3211da177e4SLinus Torvalds } else if (they_are_dirs) { 3229a53c3a7SDave Hansen drop_nlink(old_dir); 323d8c76e6fSDave Hansen inc_nlink(new_dir); 3241da177e4SLinus Torvalds } 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3271da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3281da177e4SLinus Torvalds 3291da177e4SLinus Torvalds return 0; 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3331da177e4SLinus Torvalds { 334c0d92cbcSPekka J Enberg clear_highpage(page); 3351da177e4SLinus Torvalds flush_dcache_page(page); 3361da177e4SLinus Torvalds SetPageUptodate(page); 3371da177e4SLinus Torvalds unlock_page(page); 3381da177e4SLinus Torvalds return 0; 3391da177e4SLinus Torvalds } 3401da177e4SLinus Torvalds 3411da177e4SLinus Torvalds int simple_prepare_write(struct file *file, struct page *page, 3421da177e4SLinus Torvalds unsigned from, unsigned to) 3431da177e4SLinus Torvalds { 3441da177e4SLinus Torvalds if (!PageUptodate(page)) { 345eebd2aa3SChristoph Lameter if (to - from != PAGE_CACHE_SIZE) 346eebd2aa3SChristoph Lameter zero_user_segments(page, 347eebd2aa3SChristoph Lameter 0, from, 348eebd2aa3SChristoph Lameter to, PAGE_CACHE_SIZE); 3491da177e4SLinus Torvalds } 3501da177e4SLinus Torvalds return 0; 3511da177e4SLinus Torvalds } 3521da177e4SLinus Torvalds 353afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 354afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 355afddba49SNick Piggin struct page **pagep, void **fsdata) 356afddba49SNick Piggin { 357afddba49SNick Piggin struct page *page; 358afddba49SNick Piggin pgoff_t index; 359afddba49SNick Piggin unsigned from; 360afddba49SNick Piggin 361afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 362afddba49SNick Piggin from = pos & (PAGE_CACHE_SIZE - 1); 363afddba49SNick Piggin 36454566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 365afddba49SNick Piggin if (!page) 366afddba49SNick Piggin return -ENOMEM; 367afddba49SNick Piggin 368afddba49SNick Piggin *pagep = page; 369afddba49SNick Piggin 370afddba49SNick Piggin return simple_prepare_write(file, page, from, from+len); 371afddba49SNick Piggin } 372afddba49SNick Piggin 3734a239427SAdrian Bunk static int simple_commit_write(struct file *file, struct page *page, 374955eff5aSNick Piggin unsigned from, unsigned to) 3751da177e4SLinus Torvalds { 3761da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 3771da177e4SLinus Torvalds loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; 3781da177e4SLinus Torvalds 379955eff5aSNick Piggin if (!PageUptodate(page)) 380955eff5aSNick Piggin SetPageUptodate(page); 3811da177e4SLinus Torvalds /* 3821da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 3831b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 3841da177e4SLinus Torvalds */ 3851da177e4SLinus Torvalds if (pos > inode->i_size) 3861da177e4SLinus Torvalds i_size_write(inode, pos); 3871da177e4SLinus Torvalds set_page_dirty(page); 3881da177e4SLinus Torvalds return 0; 3891da177e4SLinus Torvalds } 3901da177e4SLinus Torvalds 391afddba49SNick Piggin int simple_write_end(struct file *file, struct address_space *mapping, 392afddba49SNick Piggin loff_t pos, unsigned len, unsigned copied, 393afddba49SNick Piggin struct page *page, void *fsdata) 394afddba49SNick Piggin { 395afddba49SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 396afddba49SNick Piggin 397afddba49SNick Piggin /* zero the stale part of the page if we did a short copy */ 398afddba49SNick Piggin if (copied < len) { 399afddba49SNick Piggin void *kaddr = kmap_atomic(page, KM_USER0); 400afddba49SNick Piggin memset(kaddr + from + copied, 0, len - copied); 401afddba49SNick Piggin flush_dcache_page(page); 402afddba49SNick Piggin kunmap_atomic(kaddr, KM_USER0); 403afddba49SNick Piggin } 404afddba49SNick Piggin 405afddba49SNick Piggin simple_commit_write(file, page, from, from+copied); 406afddba49SNick Piggin 407afddba49SNick Piggin unlock_page(page); 408afddba49SNick Piggin page_cache_release(page); 409afddba49SNick Piggin 410afddba49SNick Piggin return copied; 411afddba49SNick Piggin } 412afddba49SNick Piggin 4131a1c9bb4SJeff Layton /* 4141a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4151a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4161a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4171a1c9bb4SJeff Layton */ 4181da177e4SLinus Torvalds int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) 4191da177e4SLinus Torvalds { 4201da177e4SLinus Torvalds struct inode *inode; 4211da177e4SLinus Torvalds struct dentry *root; 4221da177e4SLinus Torvalds struct dentry *dentry; 4231da177e4SLinus Torvalds int i; 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 4261da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 4271da177e4SLinus Torvalds s->s_magic = magic; 428759b9775SHugh Dickins s->s_op = &simple_super_operations; 4291da177e4SLinus Torvalds s->s_time_gran = 1; 4301da177e4SLinus Torvalds 4311da177e4SLinus Torvalds inode = new_inode(s); 4321da177e4SLinus Torvalds if (!inode) 4331da177e4SLinus Torvalds return -ENOMEM; 4341a1c9bb4SJeff Layton /* 4351a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 4361a1c9bb4SJeff Layton * entry at index 1 4371a1c9bb4SJeff Layton */ 4381a1c9bb4SJeff Layton inode->i_ino = 1; 4391da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 4401da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4411da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4421da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 4437656f328SVincent Hanquez inode->i_nlink = 2; 4441da177e4SLinus Torvalds root = d_alloc_root(inode); 4451da177e4SLinus Torvalds if (!root) { 4461da177e4SLinus Torvalds iput(inode); 4471da177e4SLinus Torvalds return -ENOMEM; 4481da177e4SLinus Torvalds } 4491da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 4501da177e4SLinus Torvalds if (!files->name) 4511da177e4SLinus Torvalds continue; 4521a1c9bb4SJeff Layton 4531a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 4541a1c9bb4SJeff Layton if (unlikely(i == 1)) 4551a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 4561a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 4571a1c9bb4SJeff Layton s->s_type->name); 4581a1c9bb4SJeff Layton 4591da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 4601da177e4SLinus Torvalds if (!dentry) 4611da177e4SLinus Torvalds goto out; 4621da177e4SLinus Torvalds inode = new_inode(s); 4631da177e4SLinus Torvalds if (!inode) 4641da177e4SLinus Torvalds goto out; 4651da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 4661da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4671da177e4SLinus Torvalds inode->i_fop = files->ops; 4681da177e4SLinus Torvalds inode->i_ino = i; 4691da177e4SLinus Torvalds d_add(dentry, inode); 4701da177e4SLinus Torvalds } 4711da177e4SLinus Torvalds s->s_root = root; 4721da177e4SLinus Torvalds return 0; 4731da177e4SLinus Torvalds out: 4741da177e4SLinus Torvalds d_genocide(root); 4751da177e4SLinus Torvalds dput(root); 4761da177e4SLinus Torvalds return -ENOMEM; 4771da177e4SLinus Torvalds } 4781da177e4SLinus Torvalds 4791da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 4801da177e4SLinus Torvalds 4811f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 4821da177e4SLinus Torvalds { 4831da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 4841da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 4851da177e4SLinus Torvalds if (unlikely(!*mount)) { 4861da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 4871f5ce9e9STrond Myklebust mnt = vfs_kern_mount(type, 0, type->name, NULL); 4881da177e4SLinus Torvalds if (IS_ERR(mnt)) 4891da177e4SLinus Torvalds return PTR_ERR(mnt); 4901da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 4911da177e4SLinus Torvalds if (!*mount) 4921da177e4SLinus Torvalds *mount = mnt; 4931da177e4SLinus Torvalds } 4941da177e4SLinus Torvalds mntget(*mount); 4951da177e4SLinus Torvalds ++*count; 4961da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 4971da177e4SLinus Torvalds mntput(mnt); 4981da177e4SLinus Torvalds return 0; 4991da177e4SLinus Torvalds } 5001da177e4SLinus Torvalds 5011da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5021da177e4SLinus Torvalds { 5031da177e4SLinus Torvalds struct vfsmount *mnt; 5041da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5051da177e4SLinus Torvalds mnt = *mount; 5061da177e4SLinus Torvalds if (!--*count) 5071da177e4SLinus Torvalds *mount = NULL; 5081da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5091da177e4SLinus Torvalds mntput(mnt); 5101da177e4SLinus Torvalds } 5111da177e4SLinus Torvalds 5126d1029b5SAkinobu Mita /** 5136d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5146d1029b5SAkinobu Mita * @to: the user space buffer to read to 5156d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5166d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5176d1029b5SAkinobu Mita * @from: the buffer to read from 5186d1029b5SAkinobu Mita * @available: the size of the buffer 5196d1029b5SAkinobu Mita * 5206d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 5216d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 5226d1029b5SAkinobu Mita * 5236d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5246d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5256d1029b5SAkinobu Mita **/ 5261da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 5271da177e4SLinus Torvalds const void *from, size_t available) 5281da177e4SLinus Torvalds { 5291da177e4SLinus Torvalds loff_t pos = *ppos; 5301da177e4SLinus Torvalds if (pos < 0) 5311da177e4SLinus Torvalds return -EINVAL; 5321da177e4SLinus Torvalds if (pos >= available) 5331da177e4SLinus Torvalds return 0; 5341da177e4SLinus Torvalds if (count > available - pos) 5351da177e4SLinus Torvalds count = available - pos; 5361da177e4SLinus Torvalds if (copy_to_user(to, from + pos, count)) 5371da177e4SLinus Torvalds return -EFAULT; 5381da177e4SLinus Torvalds *ppos = pos + count; 5391da177e4SLinus Torvalds return count; 5401da177e4SLinus Torvalds } 5411da177e4SLinus Torvalds 5426d1029b5SAkinobu Mita /** 5436d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 5446d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 5456d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5466d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5476d1029b5SAkinobu Mita * @from: the buffer to read from 5486d1029b5SAkinobu Mita * @available: the size of the buffer 5496d1029b5SAkinobu Mita * 5506d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 5516d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 5526d1029b5SAkinobu Mita * 5536d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5546d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5556d1029b5SAkinobu Mita **/ 55693b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 55793b07113SAkinobu Mita const void *from, size_t available) 55893b07113SAkinobu Mita { 55993b07113SAkinobu Mita loff_t pos = *ppos; 56093b07113SAkinobu Mita 56193b07113SAkinobu Mita if (pos < 0) 56293b07113SAkinobu Mita return -EINVAL; 56393b07113SAkinobu Mita if (pos >= available) 56493b07113SAkinobu Mita return 0; 56593b07113SAkinobu Mita if (count > available - pos) 56693b07113SAkinobu Mita count = available - pos; 56793b07113SAkinobu Mita memcpy(to, from + pos, count); 56893b07113SAkinobu Mita *ppos = pos + count; 56993b07113SAkinobu Mita 57093b07113SAkinobu Mita return count; 57193b07113SAkinobu Mita } 57293b07113SAkinobu Mita 5731da177e4SLinus Torvalds /* 5741da177e4SLinus Torvalds * Transaction based IO. 5751da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 5761da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 5771da177e4SLinus Torvalds * file-local buffer. 5781da177e4SLinus Torvalds */ 57976791ab2SIngo Molnar 58076791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 58176791ab2SIngo Molnar { 58276791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 58376791ab2SIngo Molnar 58476791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 58576791ab2SIngo Molnar 58676791ab2SIngo Molnar /* 58776791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 58876791ab2SIngo Molnar * ar->data is ready for reading. 58976791ab2SIngo Molnar */ 59076791ab2SIngo Molnar smp_mb(); 59176791ab2SIngo Molnar ar->size = n; 59276791ab2SIngo Molnar } 59376791ab2SIngo Molnar 5941da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 5951da177e4SLinus Torvalds { 5961da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 5971da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 6001da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 6011da177e4SLinus Torvalds 6021da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 6031da177e4SLinus Torvalds if (!ar) 6041da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 6051da177e4SLinus Torvalds 6061da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 6071da177e4SLinus Torvalds 6081da177e4SLinus Torvalds /* only one write allowed per open */ 6091da177e4SLinus Torvalds if (file->private_data) { 6101da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6111da177e4SLinus Torvalds free_page((unsigned long)ar); 6121da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds 6151da177e4SLinus Torvalds file->private_data = ar; 6161da177e4SLinus Torvalds 6171da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6181da177e4SLinus Torvalds 6191da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 6201da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 6211da177e4SLinus Torvalds 6221da177e4SLinus Torvalds return ar->data; 6231da177e4SLinus Torvalds } 6241da177e4SLinus Torvalds 6251da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 6261da177e4SLinus Torvalds { 6271da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 6281da177e4SLinus Torvalds 6291da177e4SLinus Torvalds if (!ar) 6301da177e4SLinus Torvalds return 0; 6311da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 6321da177e4SLinus Torvalds } 6331da177e4SLinus Torvalds 6341da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 6351da177e4SLinus Torvalds { 6361da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 6371da177e4SLinus Torvalds return 0; 6381da177e4SLinus Torvalds } 6391da177e4SLinus Torvalds 640acaefc25SArnd Bergmann /* Simple attribute files */ 641acaefc25SArnd Bergmann 642acaefc25SArnd Bergmann struct simple_attr { 6438b88b099SChristoph Hellwig int (*get)(void *, u64 *); 6448b88b099SChristoph Hellwig int (*set)(void *, u64); 645acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 646acaefc25SArnd Bergmann char set_buf[24]; 647acaefc25SArnd Bergmann void *data; 648acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 6497cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 650acaefc25SArnd Bergmann }; 651acaefc25SArnd Bergmann 652acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 653acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 654acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 6558b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 656acaefc25SArnd Bergmann const char *fmt) 657acaefc25SArnd Bergmann { 658acaefc25SArnd Bergmann struct simple_attr *attr; 659acaefc25SArnd Bergmann 660acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 661acaefc25SArnd Bergmann if (!attr) 662acaefc25SArnd Bergmann return -ENOMEM; 663acaefc25SArnd Bergmann 664acaefc25SArnd Bergmann attr->get = get; 665acaefc25SArnd Bergmann attr->set = set; 6668e18e294STheodore Ts'o attr->data = inode->i_private; 667acaefc25SArnd Bergmann attr->fmt = fmt; 6687cf34c76SIngo Molnar mutex_init(&attr->mutex); 669acaefc25SArnd Bergmann 670acaefc25SArnd Bergmann file->private_data = attr; 671acaefc25SArnd Bergmann 672acaefc25SArnd Bergmann return nonseekable_open(inode, file); 673acaefc25SArnd Bergmann } 674acaefc25SArnd Bergmann 67574bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 676acaefc25SArnd Bergmann { 677acaefc25SArnd Bergmann kfree(file->private_data); 678acaefc25SArnd Bergmann return 0; 679acaefc25SArnd Bergmann } 680acaefc25SArnd Bergmann 681acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 682acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 683acaefc25SArnd Bergmann size_t len, loff_t *ppos) 684acaefc25SArnd Bergmann { 685acaefc25SArnd Bergmann struct simple_attr *attr; 686acaefc25SArnd Bergmann size_t size; 687acaefc25SArnd Bergmann ssize_t ret; 688acaefc25SArnd Bergmann 689acaefc25SArnd Bergmann attr = file->private_data; 690acaefc25SArnd Bergmann 691acaefc25SArnd Bergmann if (!attr->get) 692acaefc25SArnd Bergmann return -EACCES; 693acaefc25SArnd Bergmann 6949261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 6959261303aSChristoph Hellwig if (ret) 6969261303aSChristoph Hellwig return ret; 6979261303aSChristoph Hellwig 6988b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 699acaefc25SArnd Bergmann size = strlen(attr->get_buf); 7008b88b099SChristoph Hellwig } else { /* first read */ 7018b88b099SChristoph Hellwig u64 val; 7028b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 7038b88b099SChristoph Hellwig if (ret) 7048b88b099SChristoph Hellwig goto out; 7058b88b099SChristoph Hellwig 706acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 7078b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 7088b88b099SChristoph Hellwig } 709acaefc25SArnd Bergmann 710acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 7118b88b099SChristoph Hellwig out: 7127cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 713acaefc25SArnd Bergmann return ret; 714acaefc25SArnd Bergmann } 715acaefc25SArnd Bergmann 716acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 717acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 718acaefc25SArnd Bergmann size_t len, loff_t *ppos) 719acaefc25SArnd Bergmann { 720acaefc25SArnd Bergmann struct simple_attr *attr; 721acaefc25SArnd Bergmann u64 val; 722acaefc25SArnd Bergmann size_t size; 723acaefc25SArnd Bergmann ssize_t ret; 724acaefc25SArnd Bergmann 725acaefc25SArnd Bergmann attr = file->private_data; 726acaefc25SArnd Bergmann if (!attr->set) 727acaefc25SArnd Bergmann return -EACCES; 728acaefc25SArnd Bergmann 7299261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 7309261303aSChristoph Hellwig if (ret) 7319261303aSChristoph Hellwig return ret; 7329261303aSChristoph Hellwig 733acaefc25SArnd Bergmann ret = -EFAULT; 734acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 735acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 736acaefc25SArnd Bergmann goto out; 737acaefc25SArnd Bergmann 738acaefc25SArnd Bergmann ret = len; /* claim we got the whole input */ 739acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 740acaefc25SArnd Bergmann val = simple_strtol(attr->set_buf, NULL, 0); 741acaefc25SArnd Bergmann attr->set(attr->data, val); 742acaefc25SArnd Bergmann out: 7437cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 744acaefc25SArnd Bergmann return ret; 745acaefc25SArnd Bergmann } 746acaefc25SArnd Bergmann 7472596110aSChristoph Hellwig /** 7482596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 7492596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 7502596110aSChristoph Hellwig * @fid: file handle to convert 7512596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 7522596110aSChristoph Hellwig * @fh_type: type of file handle 7532596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 7542596110aSChristoph Hellwig * 7552596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 7562596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 7572596110aSChristoph Hellwig * inode for the object specified in the file handle. 7582596110aSChristoph Hellwig */ 7592596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 7602596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 7612596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 7622596110aSChristoph Hellwig { 7632596110aSChristoph Hellwig struct inode *inode = NULL; 7642596110aSChristoph Hellwig 7652596110aSChristoph Hellwig if (fh_len < 2) 7662596110aSChristoph Hellwig return NULL; 7672596110aSChristoph Hellwig 7682596110aSChristoph Hellwig switch (fh_type) { 7692596110aSChristoph Hellwig case FILEID_INO32_GEN: 7702596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 7712596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 7722596110aSChristoph Hellwig break; 7732596110aSChristoph Hellwig } 7742596110aSChristoph Hellwig 7754ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 7762596110aSChristoph Hellwig } 7772596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 7782596110aSChristoph Hellwig 7792596110aSChristoph Hellwig /** 7802596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_parent export operation 7812596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 7822596110aSChristoph Hellwig * @fid: file handle to convert 7832596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 7842596110aSChristoph Hellwig * @fh_type: type of file handle 7852596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 7862596110aSChristoph Hellwig * 7872596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 7882596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 7892596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 7902596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 7912596110aSChristoph Hellwig */ 7922596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 7932596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 7942596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 7952596110aSChristoph Hellwig { 7962596110aSChristoph Hellwig struct inode *inode = NULL; 7972596110aSChristoph Hellwig 7982596110aSChristoph Hellwig if (fh_len <= 2) 7992596110aSChristoph Hellwig return NULL; 8002596110aSChristoph Hellwig 8012596110aSChristoph Hellwig switch (fh_type) { 8022596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8032596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 8042596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 8052596110aSChristoph Hellwig break; 8062596110aSChristoph Hellwig } 8072596110aSChristoph Hellwig 8084ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8092596110aSChristoph Hellwig } 8102596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 8112596110aSChristoph Hellwig 812d5aacad5SAl Viro int simple_fsync(struct file *file, struct dentry *dentry, int datasync) 813d5aacad5SAl Viro { 814d5aacad5SAl Viro struct writeback_control wbc = { 815d5aacad5SAl Viro .sync_mode = WB_SYNC_ALL, 816d5aacad5SAl Viro .nr_to_write = 0, /* metadata-only; caller takes care of data */ 817d5aacad5SAl Viro }; 818d5aacad5SAl Viro struct inode *inode = dentry->d_inode; 819d5aacad5SAl Viro int err; 820d5aacad5SAl Viro int ret; 821d5aacad5SAl Viro 822d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 823d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 824d5aacad5SAl Viro return ret; 825d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 826d5aacad5SAl Viro return ret; 827d5aacad5SAl Viro 828d5aacad5SAl Viro err = sync_inode(inode, &wbc); 829d5aacad5SAl Viro if (ret == 0) 830d5aacad5SAl Viro ret = err; 831d5aacad5SAl Viro return ret; 832d5aacad5SAl Viro } 833d5aacad5SAl Viro EXPORT_SYMBOL(simple_fsync); 834d5aacad5SAl Viro 8351da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_close); 8361da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_lseek); 8371da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_open); 8381da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_readdir); 8391da177e4SLinus Torvalds EXPORT_SYMBOL(generic_read_dir); 8401da177e4SLinus Torvalds EXPORT_SYMBOL(get_sb_pseudo); 841afddba49SNick Piggin EXPORT_SYMBOL(simple_write_begin); 842afddba49SNick Piggin EXPORT_SYMBOL(simple_write_end); 8431da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_inode_operations); 8441da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_operations); 8451da177e4SLinus Torvalds EXPORT_SYMBOL(simple_empty); 8461da177e4SLinus Torvalds EXPORT_SYMBOL(d_alloc_name); 8471da177e4SLinus Torvalds EXPORT_SYMBOL(simple_fill_super); 8481da177e4SLinus Torvalds EXPORT_SYMBOL(simple_getattr); 8491da177e4SLinus Torvalds EXPORT_SYMBOL(simple_link); 8501da177e4SLinus Torvalds EXPORT_SYMBOL(simple_lookup); 8511da177e4SLinus Torvalds EXPORT_SYMBOL(simple_pin_fs); 8524e02ed4bSNick Piggin EXPORT_UNUSED_SYMBOL(simple_prepare_write); 8531da177e4SLinus Torvalds EXPORT_SYMBOL(simple_readpage); 8541da177e4SLinus Torvalds EXPORT_SYMBOL(simple_release_fs); 8551da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rename); 8561da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rmdir); 8571da177e4SLinus Torvalds EXPORT_SYMBOL(simple_statfs); 8581da177e4SLinus Torvalds EXPORT_SYMBOL(simple_sync_file); 8591da177e4SLinus Torvalds EXPORT_SYMBOL(simple_unlink); 8601da177e4SLinus Torvalds EXPORT_SYMBOL(simple_read_from_buffer); 86193b07113SAkinobu Mita EXPORT_SYMBOL(memory_read_from_buffer); 86276791ab2SIngo Molnar EXPORT_SYMBOL(simple_transaction_set); 8631da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_get); 8641da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_read); 8651da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_release); 866acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_open); 86774bedc4dSChristoph Hellwig EXPORT_SYMBOL_GPL(simple_attr_release); 868acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_read); 869acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_write); 870