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> 85a0e3ad6STejun Heo #include <linux/slab.h> 91da177e4SLinus Torvalds #include <linux/mount.h> 101da177e4SLinus Torvalds #include <linux/vfs.h> 117bb46a67Snpiggin@suse.de #include <linux/quotaops.h> 127cf34c76SIngo Molnar #include <linux/mutex.h> 132596110aSChristoph Hellwig #include <linux/exportfs.h> 14d5aacad5SAl Viro #include <linux/writeback.h> 15d5aacad5SAl Viro #include <linux/buffer_head.h> 167cf34c76SIngo Molnar 171da177e4SLinus Torvalds #include <asm/uaccess.h> 181da177e4SLinus Torvalds 19da502956SNick Piggin static inline int simple_positive(struct dentry *dentry) 20da502956SNick Piggin { 21da502956SNick Piggin return dentry->d_inode && !d_unhashed(dentry); 22da502956SNick Piggin } 23da502956SNick Piggin 241da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 251da177e4SLinus Torvalds struct kstat *stat) 261da177e4SLinus Torvalds { 271da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 281da177e4SLinus Torvalds generic_fillattr(inode, stat); 291da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 301da177e4SLinus Torvalds return 0; 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds 33726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 341da177e4SLinus Torvalds { 35726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 361da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 371da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 381da177e4SLinus Torvalds return 0; 391da177e4SLinus Torvalds } 401da177e4SLinus Torvalds 411da177e4SLinus Torvalds /* 421da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 431da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 441da177e4SLinus Torvalds */ 45fe15ce44SNick Piggin static int simple_delete_dentry(const struct dentry *dentry) 461da177e4SLinus Torvalds { 471da177e4SLinus Torvalds return 1; 481da177e4SLinus Torvalds } 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds /* 511da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 521da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 531da177e4SLinus Torvalds */ 541da177e4SLinus Torvalds struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 551da177e4SLinus Torvalds { 563ba13d17SAl Viro static const struct dentry_operations simple_dentry_operations = { 571da177e4SLinus Torvalds .d_delete = simple_delete_dentry, 581da177e4SLinus Torvalds }; 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 611da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 621da177e4SLinus Torvalds dentry->d_op = &simple_dentry_operations; 631da177e4SLinus Torvalds d_add(dentry, NULL); 641da177e4SLinus Torvalds return NULL; 651da177e4SLinus Torvalds } 661da177e4SLinus Torvalds 671da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 681da177e4SLinus Torvalds { 691da177e4SLinus Torvalds static struct qstr cursor_name = {.len = 1, .name = "."}; 701da177e4SLinus Torvalds 710f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 741da177e4SLinus Torvalds } 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 771da177e4SLinus Torvalds { 781da177e4SLinus Torvalds dput(file->private_data); 791da177e4SLinus Torvalds return 0; 801da177e4SLinus Torvalds } 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) 831da177e4SLinus Torvalds { 840f7fc9e4SJosef "Jeff" Sipek mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 851da177e4SLinus Torvalds switch (origin) { 861da177e4SLinus Torvalds case 1: 871da177e4SLinus Torvalds offset += file->f_pos; 881da177e4SLinus Torvalds case 0: 891da177e4SLinus Torvalds if (offset >= 0) 901da177e4SLinus Torvalds break; 911da177e4SLinus Torvalds default: 920f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 931da177e4SLinus Torvalds return -EINVAL; 941da177e4SLinus Torvalds } 951da177e4SLinus Torvalds if (offset != file->f_pos) { 961da177e4SLinus Torvalds file->f_pos = offset; 971da177e4SLinus Torvalds if (file->f_pos >= 2) { 981da177e4SLinus Torvalds struct list_head *p; 991da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 1001da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds spin_lock(&dcache_lock); 1035160ee6fSEric Dumazet list_del(&cursor->d_u.d_child); 1040f7fc9e4SJosef "Jeff" Sipek p = file->f_path.dentry->d_subdirs.next; 1050f7fc9e4SJosef "Jeff" Sipek while (n && p != &file->f_path.dentry->d_subdirs) { 1061da177e4SLinus Torvalds struct dentry *next; 1075160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 108da502956SNick Piggin spin_lock(&next->d_lock); 109da502956SNick Piggin if (simple_positive(next)) 1101da177e4SLinus Torvalds n--; 111da502956SNick Piggin spin_unlock(&next->d_lock); 1121da177e4SLinus Torvalds p = p->next; 1131da177e4SLinus Torvalds } 1145160ee6fSEric Dumazet list_add_tail(&cursor->d_u.d_child, p); 1151da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1161da177e4SLinus Torvalds } 1171da177e4SLinus Torvalds } 1180f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 1191da177e4SLinus Torvalds return offset; 1201da177e4SLinus Torvalds } 1211da177e4SLinus Torvalds 1221da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1231da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1241da177e4SLinus Torvalds { 1251da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds /* 1291da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1301da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1311da177e4SLinus Torvalds * both impossible due to the lock on directory. 1321da177e4SLinus Torvalds */ 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) 1351da177e4SLinus Torvalds { 1360f7fc9e4SJosef "Jeff" Sipek struct dentry *dentry = filp->f_path.dentry; 1371da177e4SLinus Torvalds struct dentry *cursor = filp->private_data; 1385160ee6fSEric Dumazet struct list_head *p, *q = &cursor->d_u.d_child; 1391da177e4SLinus Torvalds ino_t ino; 1401da177e4SLinus Torvalds int i = filp->f_pos; 1411da177e4SLinus Torvalds 1421da177e4SLinus Torvalds switch (i) { 1431da177e4SLinus Torvalds case 0: 1441da177e4SLinus Torvalds ino = dentry->d_inode->i_ino; 1451da177e4SLinus Torvalds if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 1461da177e4SLinus Torvalds break; 1471da177e4SLinus Torvalds filp->f_pos++; 1481da177e4SLinus Torvalds i++; 1491da177e4SLinus Torvalds /* fallthrough */ 1501da177e4SLinus Torvalds case 1: 1511da177e4SLinus Torvalds ino = parent_ino(dentry); 1521da177e4SLinus Torvalds if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1531da177e4SLinus Torvalds break; 1541da177e4SLinus Torvalds filp->f_pos++; 1551da177e4SLinus Torvalds i++; 1561da177e4SLinus Torvalds /* fallthrough */ 1571da177e4SLinus Torvalds default: 1581da177e4SLinus Torvalds spin_lock(&dcache_lock); 1591bfba4e8SAkinobu Mita if (filp->f_pos == 2) 1601bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1611bfba4e8SAkinobu Mita 1621da177e4SLinus Torvalds for (p=q->next; p != &dentry->d_subdirs; p=p->next) { 1631da177e4SLinus Torvalds struct dentry *next; 1645160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 165da502956SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 166da502956SNick Piggin if (!simple_positive(next)) { 167da502956SNick Piggin spin_unlock(&next->d_lock); 1681da177e4SLinus Torvalds continue; 169da502956SNick Piggin } 1701da177e4SLinus Torvalds 171da502956SNick Piggin spin_unlock(&next->d_lock); 1721da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1730f8952c2SRonni Nielsen if (filldir(dirent, next->d_name.name, 1740f8952c2SRonni Nielsen next->d_name.len, filp->f_pos, 1750f8952c2SRonni Nielsen next->d_inode->i_ino, 1760f8952c2SRonni Nielsen dt_type(next->d_inode)) < 0) 1771da177e4SLinus Torvalds return 0; 1781da177e4SLinus Torvalds spin_lock(&dcache_lock); 1791da177e4SLinus Torvalds /* next is still alive */ 1801bfba4e8SAkinobu Mita list_move(q, p); 1811da177e4SLinus Torvalds p = q; 1821da177e4SLinus Torvalds filp->f_pos++; 1831da177e4SLinus Torvalds } 1841da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1851da177e4SLinus Torvalds } 1861da177e4SLinus Torvalds return 0; 1871da177e4SLinus Torvalds } 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1901da177e4SLinus Torvalds { 1911da177e4SLinus Torvalds return -EISDIR; 1921da177e4SLinus Torvalds } 1931da177e4SLinus Torvalds 1944b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1951da177e4SLinus Torvalds .open = dcache_dir_open, 1961da177e4SLinus Torvalds .release = dcache_dir_close, 1971da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1981da177e4SLinus Torvalds .read = generic_read_dir, 1991da177e4SLinus Torvalds .readdir = dcache_readdir, 2001b061d92SChristoph Hellwig .fsync = noop_fsync, 2011da177e4SLinus Torvalds }; 2021da177e4SLinus Torvalds 20392e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 2041da177e4SLinus Torvalds .lookup = simple_lookup, 2051da177e4SLinus Torvalds }; 2061da177e4SLinus Torvalds 207759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 208759b9775SHugh Dickins .statfs = simple_statfs, 209759b9775SHugh Dickins }; 210759b9775SHugh Dickins 2111da177e4SLinus Torvalds /* 2121da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 2131da177e4SLinus Torvalds * will never be mountable) 2141da177e4SLinus Torvalds */ 21551139adaSAl Viro struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, 21651139adaSAl Viro const struct super_operations *ops, unsigned long magic) 2171da177e4SLinus Torvalds { 2181da177e4SLinus Torvalds struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); 2191da177e4SLinus Torvalds struct dentry *dentry; 2201da177e4SLinus Torvalds struct inode *root; 2211da177e4SLinus Torvalds struct qstr d_name = {.name = name, .len = strlen(name)}; 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvalds if (IS_ERR(s)) 22451139adaSAl Viro return ERR_CAST(s); 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds s->s_flags = MS_NOUSER; 22789a4eb4bSJeff Layton s->s_maxbytes = MAX_LFS_FILESIZE; 2283971e1a9SAlex Nixon s->s_blocksize = PAGE_SIZE; 2293971e1a9SAlex Nixon s->s_blocksize_bits = PAGE_SHIFT; 2301da177e4SLinus Torvalds s->s_magic = magic; 231759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2321da177e4SLinus Torvalds s->s_time_gran = 1; 2331da177e4SLinus Torvalds root = new_inode(s); 2341da177e4SLinus Torvalds if (!root) 2351da177e4SLinus Torvalds goto Enomem; 2361a1c9bb4SJeff Layton /* 2371a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2381a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2391a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2401a1c9bb4SJeff Layton */ 2411a1c9bb4SJeff Layton root->i_ino = 1; 2421da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2431da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 2441da177e4SLinus Torvalds dentry = d_alloc(NULL, &d_name); 2451da177e4SLinus Torvalds if (!dentry) { 2461da177e4SLinus Torvalds iput(root); 2471da177e4SLinus Torvalds goto Enomem; 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds dentry->d_sb = s; 2501da177e4SLinus Torvalds dentry->d_parent = dentry; 2511da177e4SLinus Torvalds d_instantiate(dentry, root); 2521da177e4SLinus Torvalds s->s_root = dentry; 2531da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 25451139adaSAl Viro return dget(s->s_root); 2551da177e4SLinus Torvalds 2561da177e4SLinus Torvalds Enomem: 2576f5bbff9SAl Viro deactivate_locked_super(s); 25851139adaSAl Viro return ERR_PTR(-ENOMEM); 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 2611da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2621da177e4SLinus Torvalds { 2631da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2641da177e4SLinus Torvalds 2651da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 266d8c76e6fSDave Hansen inc_nlink(inode); 2677de9c6eeSAl Viro ihold(inode); 2681da177e4SLinus Torvalds dget(dentry); 2691da177e4SLinus Torvalds d_instantiate(dentry, inode); 2701da177e4SLinus Torvalds return 0; 2711da177e4SLinus Torvalds } 2721da177e4SLinus Torvalds 2731da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2741da177e4SLinus Torvalds { 2751da177e4SLinus Torvalds struct dentry *child; 2761da177e4SLinus Torvalds int ret = 0; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds spin_lock(&dcache_lock); 279da502956SNick Piggin list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { 280da502956SNick Piggin spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); 281da502956SNick Piggin if (simple_positive(child)) { 282da502956SNick Piggin spin_unlock(&child->d_lock); 2831da177e4SLinus Torvalds goto out; 284da502956SNick Piggin } 285da502956SNick Piggin spin_unlock(&child->d_lock); 286da502956SNick Piggin } 2871da177e4SLinus Torvalds ret = 1; 2881da177e4SLinus Torvalds out: 2891da177e4SLinus Torvalds spin_unlock(&dcache_lock); 2901da177e4SLinus Torvalds return ret; 2911da177e4SLinus Torvalds } 2921da177e4SLinus Torvalds 2931da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 2941da177e4SLinus Torvalds { 2951da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2961da177e4SLinus Torvalds 2971da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 2989a53c3a7SDave Hansen drop_nlink(inode); 2991da177e4SLinus Torvalds dput(dentry); 3001da177e4SLinus Torvalds return 0; 3011da177e4SLinus Torvalds } 3021da177e4SLinus Torvalds 3031da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 3041da177e4SLinus Torvalds { 3051da177e4SLinus Torvalds if (!simple_empty(dentry)) 3061da177e4SLinus Torvalds return -ENOTEMPTY; 3071da177e4SLinus Torvalds 3089a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 3091da177e4SLinus Torvalds simple_unlink(dir, dentry); 3109a53c3a7SDave Hansen drop_nlink(dir); 3111da177e4SLinus Torvalds return 0; 3121da177e4SLinus Torvalds } 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3151da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3161da177e4SLinus Torvalds { 3171da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3181da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3191da177e4SLinus Torvalds 3201da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3211da177e4SLinus Torvalds return -ENOTEMPTY; 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds if (new_dentry->d_inode) { 3241da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 3251da177e4SLinus Torvalds if (they_are_dirs) 3269a53c3a7SDave Hansen drop_nlink(old_dir); 3271da177e4SLinus Torvalds } else if (they_are_dirs) { 3289a53c3a7SDave Hansen drop_nlink(old_dir); 329d8c76e6fSDave Hansen inc_nlink(new_dir); 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3331da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3341da177e4SLinus Torvalds 3351da177e4SLinus Torvalds return 0; 3361da177e4SLinus Torvalds } 3371da177e4SLinus Torvalds 3387bb46a67Snpiggin@suse.de /** 339eef2380cSChristoph Hellwig * simple_setattr - setattr for simple filesystem 3407bb46a67Snpiggin@suse.de * @dentry: dentry 3417bb46a67Snpiggin@suse.de * @iattr: iattr structure 3427bb46a67Snpiggin@suse.de * 3437bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3447bb46a67Snpiggin@suse.de * 345eef2380cSChristoph Hellwig * simple_setattr is a simple ->setattr implementation without a proper 346eef2380cSChristoph Hellwig * implementation of size changes. 347eef2380cSChristoph Hellwig * 348eef2380cSChristoph Hellwig * It can either be used for in-memory filesystems or special files 349eef2380cSChristoph Hellwig * on simple regular filesystems. Anything that needs to change on-disk 350eef2380cSChristoph Hellwig * or wire state on size changes needs its own setattr method. 3517bb46a67Snpiggin@suse.de */ 3527bb46a67Snpiggin@suse.de int simple_setattr(struct dentry *dentry, struct iattr *iattr) 3537bb46a67Snpiggin@suse.de { 3547bb46a67Snpiggin@suse.de struct inode *inode = dentry->d_inode; 3557bb46a67Snpiggin@suse.de int error; 3567bb46a67Snpiggin@suse.de 357eef2380cSChristoph Hellwig WARN_ON_ONCE(inode->i_op->truncate); 358eef2380cSChristoph Hellwig 3597bb46a67Snpiggin@suse.de error = inode_change_ok(inode, iattr); 3607bb46a67Snpiggin@suse.de if (error) 3617bb46a67Snpiggin@suse.de return error; 3627bb46a67Snpiggin@suse.de 3632c27c65eSChristoph Hellwig if (iattr->ia_valid & ATTR_SIZE) 3642c27c65eSChristoph Hellwig truncate_setsize(inode, iattr->ia_size); 3656a1a90adSChristoph Hellwig setattr_copy(inode, iattr); 366eef2380cSChristoph Hellwig mark_inode_dirty(inode); 367eef2380cSChristoph Hellwig return 0; 3687bb46a67Snpiggin@suse.de } 3697bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setattr); 3707bb46a67Snpiggin@suse.de 3711da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3721da177e4SLinus Torvalds { 373c0d92cbcSPekka J Enberg clear_highpage(page); 3741da177e4SLinus Torvalds flush_dcache_page(page); 3751da177e4SLinus Torvalds SetPageUptodate(page); 3761da177e4SLinus Torvalds unlock_page(page); 3771da177e4SLinus Torvalds return 0; 3781da177e4SLinus Torvalds } 3791da177e4SLinus Torvalds 380afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 381afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 382afddba49SNick Piggin struct page **pagep, void **fsdata) 383afddba49SNick Piggin { 384afddba49SNick Piggin struct page *page; 385afddba49SNick Piggin pgoff_t index; 386afddba49SNick Piggin 387afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 388afddba49SNick Piggin 38954566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 390afddba49SNick Piggin if (!page) 391afddba49SNick Piggin return -ENOMEM; 392afddba49SNick Piggin 393afddba49SNick Piggin *pagep = page; 394afddba49SNick Piggin 395193cf4b9SBoaz Harrosh if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { 396193cf4b9SBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 397193cf4b9SBoaz Harrosh 398193cf4b9SBoaz Harrosh zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); 399193cf4b9SBoaz Harrosh } 400193cf4b9SBoaz Harrosh return 0; 401afddba49SNick Piggin } 402afddba49SNick Piggin 403ad2a722fSBoaz Harrosh /** 404ad2a722fSBoaz Harrosh * simple_write_end - .write_end helper for non-block-device FSes 405ad2a722fSBoaz Harrosh * @available: See .write_end of address_space_operations 406ad2a722fSBoaz Harrosh * @file: " 407ad2a722fSBoaz Harrosh * @mapping: " 408ad2a722fSBoaz Harrosh * @pos: " 409ad2a722fSBoaz Harrosh * @len: " 410ad2a722fSBoaz Harrosh * @copied: " 411ad2a722fSBoaz Harrosh * @page: " 412ad2a722fSBoaz Harrosh * @fsdata: " 413ad2a722fSBoaz Harrosh * 414ad2a722fSBoaz Harrosh * simple_write_end does the minimum needed for updating a page after writing is 415ad2a722fSBoaz Harrosh * done. It has the same API signature as the .write_end of 416ad2a722fSBoaz Harrosh * address_space_operations vector. So it can just be set onto .write_end for 417ad2a722fSBoaz Harrosh * FSes that don't need any other processing. i_mutex is assumed to be held. 418ad2a722fSBoaz Harrosh * Block based filesystems should use generic_write_end(). 419ad2a722fSBoaz Harrosh * NOTE: Even though i_size might get updated by this function, mark_inode_dirty 420ad2a722fSBoaz Harrosh * is not called, so a filesystem that actually does store data in .write_inode 421ad2a722fSBoaz Harrosh * should extend on what's done here with a call to mark_inode_dirty() in the 422ad2a722fSBoaz Harrosh * case that i_size has changed. 423ad2a722fSBoaz Harrosh */ 424ad2a722fSBoaz Harrosh int simple_write_end(struct file *file, struct address_space *mapping, 425ad2a722fSBoaz Harrosh loff_t pos, unsigned len, unsigned copied, 426ad2a722fSBoaz Harrosh struct page *page, void *fsdata) 4271da177e4SLinus Torvalds { 4281da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 429ad2a722fSBoaz Harrosh loff_t last_pos = pos + copied; 430ad2a722fSBoaz Harrosh 431ad2a722fSBoaz Harrosh /* zero the stale part of the page if we did a short copy */ 432ad2a722fSBoaz Harrosh if (copied < len) { 433ad2a722fSBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 434ad2a722fSBoaz Harrosh 435ad2a722fSBoaz Harrosh zero_user(page, from + copied, len - copied); 436ad2a722fSBoaz Harrosh } 4371da177e4SLinus Torvalds 438955eff5aSNick Piggin if (!PageUptodate(page)) 439955eff5aSNick Piggin SetPageUptodate(page); 4401da177e4SLinus Torvalds /* 4411da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 4421b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 4431da177e4SLinus Torvalds */ 444ad2a722fSBoaz Harrosh if (last_pos > inode->i_size) 445ad2a722fSBoaz Harrosh i_size_write(inode, last_pos); 446ad2a722fSBoaz Harrosh 4471da177e4SLinus Torvalds set_page_dirty(page); 448afddba49SNick Piggin unlock_page(page); 449afddba49SNick Piggin page_cache_release(page); 450afddba49SNick Piggin 451afddba49SNick Piggin return copied; 452afddba49SNick Piggin } 453afddba49SNick Piggin 4541a1c9bb4SJeff Layton /* 4551a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4561a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4571a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4581a1c9bb4SJeff Layton */ 4597d683a09SRoberto Sassu int simple_fill_super(struct super_block *s, unsigned long magic, 4607d683a09SRoberto Sassu struct tree_descr *files) 4611da177e4SLinus Torvalds { 4621da177e4SLinus Torvalds struct inode *inode; 4631da177e4SLinus Torvalds struct dentry *root; 4641da177e4SLinus Torvalds struct dentry *dentry; 4651da177e4SLinus Torvalds int i; 4661da177e4SLinus Torvalds 4671da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 4681da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 4691da177e4SLinus Torvalds s->s_magic = magic; 470759b9775SHugh Dickins s->s_op = &simple_super_operations; 4711da177e4SLinus Torvalds s->s_time_gran = 1; 4721da177e4SLinus Torvalds 4731da177e4SLinus Torvalds inode = new_inode(s); 4741da177e4SLinus Torvalds if (!inode) 4751da177e4SLinus Torvalds return -ENOMEM; 4761a1c9bb4SJeff Layton /* 4771a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 4781a1c9bb4SJeff Layton * entry at index 1 4791a1c9bb4SJeff Layton */ 4801a1c9bb4SJeff Layton inode->i_ino = 1; 4811da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 4821da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4831da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4841da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 4857656f328SVincent Hanquez inode->i_nlink = 2; 4861da177e4SLinus Torvalds root = d_alloc_root(inode); 4871da177e4SLinus Torvalds if (!root) { 4881da177e4SLinus Torvalds iput(inode); 4891da177e4SLinus Torvalds return -ENOMEM; 4901da177e4SLinus Torvalds } 4911da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 4921da177e4SLinus Torvalds if (!files->name) 4931da177e4SLinus Torvalds continue; 4941a1c9bb4SJeff Layton 4951a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 4961a1c9bb4SJeff Layton if (unlikely(i == 1)) 4971a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 4981a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 4991a1c9bb4SJeff Layton s->s_type->name); 5001a1c9bb4SJeff Layton 5011da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 5021da177e4SLinus Torvalds if (!dentry) 5031da177e4SLinus Torvalds goto out; 5041da177e4SLinus Torvalds inode = new_inode(s); 5051da177e4SLinus Torvalds if (!inode) 5061da177e4SLinus Torvalds goto out; 5071da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 5081da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5091da177e4SLinus Torvalds inode->i_fop = files->ops; 5101da177e4SLinus Torvalds inode->i_ino = i; 5111da177e4SLinus Torvalds d_add(dentry, inode); 5121da177e4SLinus Torvalds } 5131da177e4SLinus Torvalds s->s_root = root; 5141da177e4SLinus Torvalds return 0; 5151da177e4SLinus Torvalds out: 5161da177e4SLinus Torvalds d_genocide(root); 5171da177e4SLinus Torvalds dput(root); 5181da177e4SLinus Torvalds return -ENOMEM; 5191da177e4SLinus Torvalds } 5201da177e4SLinus Torvalds 5211da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 5221da177e4SLinus Torvalds 5231f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 5241da177e4SLinus Torvalds { 5251da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 5261da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5271da177e4SLinus Torvalds if (unlikely(!*mount)) { 5281da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5291f5ce9e9STrond Myklebust mnt = vfs_kern_mount(type, 0, type->name, NULL); 5301da177e4SLinus Torvalds if (IS_ERR(mnt)) 5311da177e4SLinus Torvalds return PTR_ERR(mnt); 5321da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5331da177e4SLinus Torvalds if (!*mount) 5341da177e4SLinus Torvalds *mount = mnt; 5351da177e4SLinus Torvalds } 5361da177e4SLinus Torvalds mntget(*mount); 5371da177e4SLinus Torvalds ++*count; 5381da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5391da177e4SLinus Torvalds mntput(mnt); 5401da177e4SLinus Torvalds return 0; 5411da177e4SLinus Torvalds } 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5441da177e4SLinus Torvalds { 5451da177e4SLinus Torvalds struct vfsmount *mnt; 5461da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5471da177e4SLinus Torvalds mnt = *mount; 5481da177e4SLinus Torvalds if (!--*count) 5491da177e4SLinus Torvalds *mount = NULL; 5501da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5511da177e4SLinus Torvalds mntput(mnt); 5521da177e4SLinus Torvalds } 5531da177e4SLinus Torvalds 5546d1029b5SAkinobu Mita /** 5556d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5566d1029b5SAkinobu Mita * @to: the user space buffer to read to 5576d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5586d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5596d1029b5SAkinobu Mita * @from: the buffer to read from 5606d1029b5SAkinobu Mita * @available: the size of the buffer 5616d1029b5SAkinobu Mita * 5626d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 5636d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 5646d1029b5SAkinobu Mita * 5656d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5666d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5676d1029b5SAkinobu Mita **/ 5681da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 5691da177e4SLinus Torvalds const void *from, size_t available) 5701da177e4SLinus Torvalds { 5711da177e4SLinus Torvalds loff_t pos = *ppos; 57214be2746SSteven Rostedt size_t ret; 57314be2746SSteven Rostedt 5741da177e4SLinus Torvalds if (pos < 0) 5751da177e4SLinus Torvalds return -EINVAL; 57614be2746SSteven Rostedt if (pos >= available || !count) 5771da177e4SLinus Torvalds return 0; 5781da177e4SLinus Torvalds if (count > available - pos) 5791da177e4SLinus Torvalds count = available - pos; 58014be2746SSteven Rostedt ret = copy_to_user(to, from + pos, count); 58114be2746SSteven Rostedt if (ret == count) 5821da177e4SLinus Torvalds return -EFAULT; 58314be2746SSteven Rostedt count -= ret; 5841da177e4SLinus Torvalds *ppos = pos + count; 5851da177e4SLinus Torvalds return count; 5861da177e4SLinus Torvalds } 5871da177e4SLinus Torvalds 5886d1029b5SAkinobu Mita /** 5896a727b43SJiri Slaby * simple_write_to_buffer - copy data from user space to the buffer 5906a727b43SJiri Slaby * @to: the buffer to write to 5916a727b43SJiri Slaby * @available: the size of the buffer 5926a727b43SJiri Slaby * @ppos: the current position in the buffer 5936a727b43SJiri Slaby * @from: the user space buffer to read from 5946a727b43SJiri Slaby * @count: the maximum number of bytes to read 5956a727b43SJiri Slaby * 5966a727b43SJiri Slaby * The simple_write_to_buffer() function reads up to @count bytes from the user 5976a727b43SJiri Slaby * space address starting at @from into the buffer @to at offset @ppos. 5986a727b43SJiri Slaby * 5996a727b43SJiri Slaby * On success, the number of bytes written is returned and the offset @ppos is 6006a727b43SJiri Slaby * advanced by this number, or negative value is returned on error. 6016a727b43SJiri Slaby **/ 6026a727b43SJiri Slaby ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, 6036a727b43SJiri Slaby const void __user *from, size_t count) 6046a727b43SJiri Slaby { 6056a727b43SJiri Slaby loff_t pos = *ppos; 6066a727b43SJiri Slaby size_t res; 6076a727b43SJiri Slaby 6086a727b43SJiri Slaby if (pos < 0) 6096a727b43SJiri Slaby return -EINVAL; 6106a727b43SJiri Slaby if (pos >= available || !count) 6116a727b43SJiri Slaby return 0; 6126a727b43SJiri Slaby if (count > available - pos) 6136a727b43SJiri Slaby count = available - pos; 6146a727b43SJiri Slaby res = copy_from_user(to + pos, from, count); 6156a727b43SJiri Slaby if (res == count) 6166a727b43SJiri Slaby return -EFAULT; 6176a727b43SJiri Slaby count -= res; 6186a727b43SJiri Slaby *ppos = pos + count; 6196a727b43SJiri Slaby return count; 6206a727b43SJiri Slaby } 6216a727b43SJiri Slaby 6226a727b43SJiri Slaby /** 6236d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 6246d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 6256d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 6266d1029b5SAkinobu Mita * @ppos: the current position in the buffer 6276d1029b5SAkinobu Mita * @from: the buffer to read from 6286d1029b5SAkinobu Mita * @available: the size of the buffer 6296d1029b5SAkinobu Mita * 6306d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 6316d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 6326d1029b5SAkinobu Mita * 6336d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6346d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6356d1029b5SAkinobu Mita **/ 63693b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 63793b07113SAkinobu Mita const void *from, size_t available) 63893b07113SAkinobu Mita { 63993b07113SAkinobu Mita loff_t pos = *ppos; 64093b07113SAkinobu Mita 64193b07113SAkinobu Mita if (pos < 0) 64293b07113SAkinobu Mita return -EINVAL; 64393b07113SAkinobu Mita if (pos >= available) 64493b07113SAkinobu Mita return 0; 64593b07113SAkinobu Mita if (count > available - pos) 64693b07113SAkinobu Mita count = available - pos; 64793b07113SAkinobu Mita memcpy(to, from + pos, count); 64893b07113SAkinobu Mita *ppos = pos + count; 64993b07113SAkinobu Mita 65093b07113SAkinobu Mita return count; 65193b07113SAkinobu Mita } 65293b07113SAkinobu Mita 6531da177e4SLinus Torvalds /* 6541da177e4SLinus Torvalds * Transaction based IO. 6551da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 6561da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 6571da177e4SLinus Torvalds * file-local buffer. 6581da177e4SLinus Torvalds */ 65976791ab2SIngo Molnar 66076791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 66176791ab2SIngo Molnar { 66276791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 66376791ab2SIngo Molnar 66476791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 66576791ab2SIngo Molnar 66676791ab2SIngo Molnar /* 66776791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 66876791ab2SIngo Molnar * ar->data is ready for reading. 66976791ab2SIngo Molnar */ 67076791ab2SIngo Molnar smp_mb(); 67176791ab2SIngo Molnar ar->size = n; 67276791ab2SIngo Molnar } 67376791ab2SIngo Molnar 6741da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 6751da177e4SLinus Torvalds { 6761da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 6771da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 6781da177e4SLinus Torvalds 6791da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 6801da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 6811da177e4SLinus Torvalds 6821da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 6831da177e4SLinus Torvalds if (!ar) 6841da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 6871da177e4SLinus Torvalds 6881da177e4SLinus Torvalds /* only one write allowed per open */ 6891da177e4SLinus Torvalds if (file->private_data) { 6901da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6911da177e4SLinus Torvalds free_page((unsigned long)ar); 6921da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 6931da177e4SLinus Torvalds } 6941da177e4SLinus Torvalds 6951da177e4SLinus Torvalds file->private_data = ar; 6961da177e4SLinus Torvalds 6971da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6981da177e4SLinus Torvalds 6991da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 7001da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 7011da177e4SLinus Torvalds 7021da177e4SLinus Torvalds return ar->data; 7031da177e4SLinus Torvalds } 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 7061da177e4SLinus Torvalds { 7071da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 7081da177e4SLinus Torvalds 7091da177e4SLinus Torvalds if (!ar) 7101da177e4SLinus Torvalds return 0; 7111da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 7121da177e4SLinus Torvalds } 7131da177e4SLinus Torvalds 7141da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 7151da177e4SLinus Torvalds { 7161da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 7171da177e4SLinus Torvalds return 0; 7181da177e4SLinus Torvalds } 7191da177e4SLinus Torvalds 720acaefc25SArnd Bergmann /* Simple attribute files */ 721acaefc25SArnd Bergmann 722acaefc25SArnd Bergmann struct simple_attr { 7238b88b099SChristoph Hellwig int (*get)(void *, u64 *); 7248b88b099SChristoph Hellwig int (*set)(void *, u64); 725acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 726acaefc25SArnd Bergmann char set_buf[24]; 727acaefc25SArnd Bergmann void *data; 728acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 7297cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 730acaefc25SArnd Bergmann }; 731acaefc25SArnd Bergmann 732acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 733acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 734acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 7358b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 736acaefc25SArnd Bergmann const char *fmt) 737acaefc25SArnd Bergmann { 738acaefc25SArnd Bergmann struct simple_attr *attr; 739acaefc25SArnd Bergmann 740acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 741acaefc25SArnd Bergmann if (!attr) 742acaefc25SArnd Bergmann return -ENOMEM; 743acaefc25SArnd Bergmann 744acaefc25SArnd Bergmann attr->get = get; 745acaefc25SArnd Bergmann attr->set = set; 7468e18e294STheodore Ts'o attr->data = inode->i_private; 747acaefc25SArnd Bergmann attr->fmt = fmt; 7487cf34c76SIngo Molnar mutex_init(&attr->mutex); 749acaefc25SArnd Bergmann 750acaefc25SArnd Bergmann file->private_data = attr; 751acaefc25SArnd Bergmann 752acaefc25SArnd Bergmann return nonseekable_open(inode, file); 753acaefc25SArnd Bergmann } 754acaefc25SArnd Bergmann 75574bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 756acaefc25SArnd Bergmann { 757acaefc25SArnd Bergmann kfree(file->private_data); 758acaefc25SArnd Bergmann return 0; 759acaefc25SArnd Bergmann } 760acaefc25SArnd Bergmann 761acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 762acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 763acaefc25SArnd Bergmann size_t len, loff_t *ppos) 764acaefc25SArnd Bergmann { 765acaefc25SArnd Bergmann struct simple_attr *attr; 766acaefc25SArnd Bergmann size_t size; 767acaefc25SArnd Bergmann ssize_t ret; 768acaefc25SArnd Bergmann 769acaefc25SArnd Bergmann attr = file->private_data; 770acaefc25SArnd Bergmann 771acaefc25SArnd Bergmann if (!attr->get) 772acaefc25SArnd Bergmann return -EACCES; 773acaefc25SArnd Bergmann 7749261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 7759261303aSChristoph Hellwig if (ret) 7769261303aSChristoph Hellwig return ret; 7779261303aSChristoph Hellwig 7788b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 779acaefc25SArnd Bergmann size = strlen(attr->get_buf); 7808b88b099SChristoph Hellwig } else { /* first read */ 7818b88b099SChristoph Hellwig u64 val; 7828b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 7838b88b099SChristoph Hellwig if (ret) 7848b88b099SChristoph Hellwig goto out; 7858b88b099SChristoph Hellwig 786acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 7878b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 7888b88b099SChristoph Hellwig } 789acaefc25SArnd Bergmann 790acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 7918b88b099SChristoph Hellwig out: 7927cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 793acaefc25SArnd Bergmann return ret; 794acaefc25SArnd Bergmann } 795acaefc25SArnd Bergmann 796acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 797acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 798acaefc25SArnd Bergmann size_t len, loff_t *ppos) 799acaefc25SArnd Bergmann { 800acaefc25SArnd Bergmann struct simple_attr *attr; 801acaefc25SArnd Bergmann u64 val; 802acaefc25SArnd Bergmann size_t size; 803acaefc25SArnd Bergmann ssize_t ret; 804acaefc25SArnd Bergmann 805acaefc25SArnd Bergmann attr = file->private_data; 806acaefc25SArnd Bergmann if (!attr->set) 807acaefc25SArnd Bergmann return -EACCES; 808acaefc25SArnd Bergmann 8099261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8109261303aSChristoph Hellwig if (ret) 8119261303aSChristoph Hellwig return ret; 8129261303aSChristoph Hellwig 813acaefc25SArnd Bergmann ret = -EFAULT; 814acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 815acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 816acaefc25SArnd Bergmann goto out; 817acaefc25SArnd Bergmann 818acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 819acaefc25SArnd Bergmann val = simple_strtol(attr->set_buf, NULL, 0); 82005cc0ceeSWu Fengguang ret = attr->set(attr->data, val); 82105cc0ceeSWu Fengguang if (ret == 0) 82205cc0ceeSWu Fengguang ret = len; /* on success, claim we got the whole input */ 823acaefc25SArnd Bergmann out: 8247cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 825acaefc25SArnd Bergmann return ret; 826acaefc25SArnd Bergmann } 827acaefc25SArnd Bergmann 8282596110aSChristoph Hellwig /** 8292596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 8302596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8312596110aSChristoph Hellwig * @fid: file handle to convert 8322596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8332596110aSChristoph Hellwig * @fh_type: type of file handle 8342596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8352596110aSChristoph Hellwig * 8362596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8372596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8382596110aSChristoph Hellwig * inode for the object specified in the file handle. 8392596110aSChristoph Hellwig */ 8402596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 8412596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8422596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8432596110aSChristoph Hellwig { 8442596110aSChristoph Hellwig struct inode *inode = NULL; 8452596110aSChristoph Hellwig 8462596110aSChristoph Hellwig if (fh_len < 2) 8472596110aSChristoph Hellwig return NULL; 8482596110aSChristoph Hellwig 8492596110aSChristoph Hellwig switch (fh_type) { 8502596110aSChristoph Hellwig case FILEID_INO32_GEN: 8512596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8522596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 8532596110aSChristoph Hellwig break; 8542596110aSChristoph Hellwig } 8552596110aSChristoph Hellwig 8564ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8572596110aSChristoph Hellwig } 8582596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 8592596110aSChristoph Hellwig 8602596110aSChristoph Hellwig /** 8612596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_parent export operation 8622596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8632596110aSChristoph Hellwig * @fid: file handle to convert 8642596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8652596110aSChristoph Hellwig * @fh_type: type of file handle 8662596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8672596110aSChristoph Hellwig * 8682596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8692596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8702596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 8712596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 8722596110aSChristoph Hellwig */ 8732596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 8742596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8752596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8762596110aSChristoph Hellwig { 8772596110aSChristoph Hellwig struct inode *inode = NULL; 8782596110aSChristoph Hellwig 8792596110aSChristoph Hellwig if (fh_len <= 2) 8802596110aSChristoph Hellwig return NULL; 8812596110aSChristoph Hellwig 8822596110aSChristoph Hellwig switch (fh_type) { 8832596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8842596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 8852596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 8862596110aSChristoph Hellwig break; 8872596110aSChristoph Hellwig } 8882596110aSChristoph Hellwig 8894ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8902596110aSChristoph Hellwig } 8912596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 8922596110aSChristoph Hellwig 8931b061d92SChristoph Hellwig /** 8941b061d92SChristoph Hellwig * generic_file_fsync - generic fsync implementation for simple filesystems 8951b061d92SChristoph Hellwig * @file: file to synchronize 8961b061d92SChristoph Hellwig * @datasync: only synchronize essential metadata if true 8971b061d92SChristoph Hellwig * 8981b061d92SChristoph Hellwig * This is a generic implementation of the fsync method for simple 8991b061d92SChristoph Hellwig * filesystems which track all non-inode metadata in the buffers list 9001b061d92SChristoph Hellwig * hanging off the address_space structure. 9011b061d92SChristoph Hellwig */ 9021b061d92SChristoph Hellwig int generic_file_fsync(struct file *file, int datasync) 903d5aacad5SAl Viro { 9047ea80859SChristoph Hellwig struct inode *inode = file->f_mapping->host; 905d5aacad5SAl Viro int err; 906d5aacad5SAl Viro int ret; 907d5aacad5SAl Viro 908d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 909d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 910d5aacad5SAl Viro return ret; 911d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 912d5aacad5SAl Viro return ret; 913d5aacad5SAl Viro 914c3765016SChristoph Hellwig err = sync_inode_metadata(inode, 1); 915d5aacad5SAl Viro if (ret == 0) 916d5aacad5SAl Viro ret = err; 917d5aacad5SAl Viro return ret; 918d5aacad5SAl Viro } 9191b061d92SChristoph Hellwig EXPORT_SYMBOL(generic_file_fsync); 9201b061d92SChristoph Hellwig 92130ca22c7SPatrick J. LoPresti /** 92230ca22c7SPatrick J. LoPresti * generic_check_addressable - Check addressability of file system 92330ca22c7SPatrick J. LoPresti * @blocksize_bits: log of file system block size 92430ca22c7SPatrick J. LoPresti * @num_blocks: number of blocks in file system 92530ca22c7SPatrick J. LoPresti * 92630ca22c7SPatrick J. LoPresti * Determine whether a file system with @num_blocks blocks (and a 92730ca22c7SPatrick J. LoPresti * block size of 2**@blocksize_bits) is addressable by the sector_t 92830ca22c7SPatrick J. LoPresti * and page cache of the system. Return 0 if so and -EFBIG otherwise. 92930ca22c7SPatrick J. LoPresti */ 93030ca22c7SPatrick J. LoPresti int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) 93130ca22c7SPatrick J. LoPresti { 93230ca22c7SPatrick J. LoPresti u64 last_fs_block = num_blocks - 1; 933a33f13efSJoel Becker u64 last_fs_page = 934a33f13efSJoel Becker last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); 93530ca22c7SPatrick J. LoPresti 93630ca22c7SPatrick J. LoPresti if (unlikely(num_blocks == 0)) 93730ca22c7SPatrick J. LoPresti return 0; 93830ca22c7SPatrick J. LoPresti 93930ca22c7SPatrick J. LoPresti if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) 94030ca22c7SPatrick J. LoPresti return -EINVAL; 94130ca22c7SPatrick J. LoPresti 942a33f13efSJoel Becker if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || 943a33f13efSJoel Becker (last_fs_page > (pgoff_t)(~0ULL))) { 94430ca22c7SPatrick J. LoPresti return -EFBIG; 94530ca22c7SPatrick J. LoPresti } 94630ca22c7SPatrick J. LoPresti return 0; 94730ca22c7SPatrick J. LoPresti } 94830ca22c7SPatrick J. LoPresti EXPORT_SYMBOL(generic_check_addressable); 94930ca22c7SPatrick J. LoPresti 9501b061d92SChristoph Hellwig /* 9511b061d92SChristoph Hellwig * No-op implementation of ->fsync for in-memory filesystems. 9521b061d92SChristoph Hellwig */ 9531b061d92SChristoph Hellwig int noop_fsync(struct file *file, int datasync) 9541b061d92SChristoph Hellwig { 9551b061d92SChristoph Hellwig return 0; 9561b061d92SChristoph Hellwig } 957d5aacad5SAl Viro 9581da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_close); 9591da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_lseek); 9601da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_open); 9611da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_readdir); 9621da177e4SLinus Torvalds EXPORT_SYMBOL(generic_read_dir); 96351139adaSAl Viro EXPORT_SYMBOL(mount_pseudo); 964afddba49SNick Piggin EXPORT_SYMBOL(simple_write_begin); 965afddba49SNick Piggin EXPORT_SYMBOL(simple_write_end); 9661da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_inode_operations); 9671da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_operations); 9681da177e4SLinus Torvalds EXPORT_SYMBOL(simple_empty); 9691da177e4SLinus Torvalds EXPORT_SYMBOL(simple_fill_super); 9701da177e4SLinus Torvalds EXPORT_SYMBOL(simple_getattr); 9711da177e4SLinus Torvalds EXPORT_SYMBOL(simple_link); 9721da177e4SLinus Torvalds EXPORT_SYMBOL(simple_lookup); 9731da177e4SLinus Torvalds EXPORT_SYMBOL(simple_pin_fs); 9741da177e4SLinus Torvalds EXPORT_SYMBOL(simple_readpage); 9751da177e4SLinus Torvalds EXPORT_SYMBOL(simple_release_fs); 9761da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rename); 9771da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rmdir); 9781da177e4SLinus Torvalds EXPORT_SYMBOL(simple_statfs); 9791b061d92SChristoph Hellwig EXPORT_SYMBOL(noop_fsync); 9801da177e4SLinus Torvalds EXPORT_SYMBOL(simple_unlink); 9811da177e4SLinus Torvalds EXPORT_SYMBOL(simple_read_from_buffer); 9826a727b43SJiri Slaby EXPORT_SYMBOL(simple_write_to_buffer); 98393b07113SAkinobu Mita EXPORT_SYMBOL(memory_read_from_buffer); 98476791ab2SIngo Molnar EXPORT_SYMBOL(simple_transaction_set); 9851da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_get); 9861da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_read); 9871da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_release); 988acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_open); 98974bedc4dSChristoph Hellwig EXPORT_SYMBOL_GPL(simple_attr_release); 990acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_read); 991acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_write); 992