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 191da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 201da177e4SLinus Torvalds struct kstat *stat) 211da177e4SLinus Torvalds { 221da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 231da177e4SLinus Torvalds generic_fillattr(inode, stat); 241da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 251da177e4SLinus Torvalds return 0; 261da177e4SLinus Torvalds } 271da177e4SLinus Torvalds 28726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 291da177e4SLinus Torvalds { 30726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 311da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 321da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 331da177e4SLinus Torvalds return 0; 341da177e4SLinus Torvalds } 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds /* 371da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 381da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 391da177e4SLinus Torvalds */ 401da177e4SLinus Torvalds static int simple_delete_dentry(struct dentry *dentry) 411da177e4SLinus Torvalds { 421da177e4SLinus Torvalds return 1; 431da177e4SLinus Torvalds } 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds /* 461da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 471da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 481da177e4SLinus Torvalds */ 491da177e4SLinus Torvalds struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) 501da177e4SLinus Torvalds { 513ba13d17SAl Viro static const struct dentry_operations simple_dentry_operations = { 521da177e4SLinus Torvalds .d_delete = simple_delete_dentry, 531da177e4SLinus Torvalds }; 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 561da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 571da177e4SLinus Torvalds dentry->d_op = &simple_dentry_operations; 581da177e4SLinus Torvalds d_add(dentry, NULL); 591da177e4SLinus Torvalds return NULL; 601da177e4SLinus Torvalds } 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 631da177e4SLinus Torvalds { 641da177e4SLinus Torvalds static struct qstr cursor_name = {.len = 1, .name = "."}; 651da177e4SLinus Torvalds 660f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 691da177e4SLinus Torvalds } 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 721da177e4SLinus Torvalds { 731da177e4SLinus Torvalds dput(file->private_data); 741da177e4SLinus Torvalds return 0; 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) 781da177e4SLinus Torvalds { 790f7fc9e4SJosef "Jeff" Sipek mutex_lock(&file->f_path.dentry->d_inode->i_mutex); 801da177e4SLinus Torvalds switch (origin) { 811da177e4SLinus Torvalds case 1: 821da177e4SLinus Torvalds offset += file->f_pos; 831da177e4SLinus Torvalds case 0: 841da177e4SLinus Torvalds if (offset >= 0) 851da177e4SLinus Torvalds break; 861da177e4SLinus Torvalds default: 870f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 881da177e4SLinus Torvalds return -EINVAL; 891da177e4SLinus Torvalds } 901da177e4SLinus Torvalds if (offset != file->f_pos) { 911da177e4SLinus Torvalds file->f_pos = offset; 921da177e4SLinus Torvalds if (file->f_pos >= 2) { 931da177e4SLinus Torvalds struct list_head *p; 941da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 951da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 961da177e4SLinus Torvalds 971da177e4SLinus Torvalds spin_lock(&dcache_lock); 985160ee6fSEric Dumazet list_del(&cursor->d_u.d_child); 990f7fc9e4SJosef "Jeff" Sipek p = file->f_path.dentry->d_subdirs.next; 1000f7fc9e4SJosef "Jeff" Sipek while (n && p != &file->f_path.dentry->d_subdirs) { 1011da177e4SLinus Torvalds struct dentry *next; 1025160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1031da177e4SLinus Torvalds if (!d_unhashed(next) && next->d_inode) 1041da177e4SLinus Torvalds n--; 1051da177e4SLinus Torvalds p = p->next; 1061da177e4SLinus Torvalds } 1075160ee6fSEric Dumazet list_add_tail(&cursor->d_u.d_child, p); 1081da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1091da177e4SLinus Torvalds } 1101da177e4SLinus Torvalds } 1110f7fc9e4SJosef "Jeff" Sipek mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); 1121da177e4SLinus Torvalds return offset; 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds 1151da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1161da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1171da177e4SLinus Torvalds { 1181da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1191da177e4SLinus Torvalds } 1201da177e4SLinus Torvalds 1211da177e4SLinus Torvalds /* 1221da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1231da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1241da177e4SLinus Torvalds * both impossible due to the lock on directory. 1251da177e4SLinus Torvalds */ 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) 1281da177e4SLinus Torvalds { 1290f7fc9e4SJosef "Jeff" Sipek struct dentry *dentry = filp->f_path.dentry; 1301da177e4SLinus Torvalds struct dentry *cursor = filp->private_data; 1315160ee6fSEric Dumazet struct list_head *p, *q = &cursor->d_u.d_child; 1321da177e4SLinus Torvalds ino_t ino; 1331da177e4SLinus Torvalds int i = filp->f_pos; 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds switch (i) { 1361da177e4SLinus Torvalds case 0: 1371da177e4SLinus Torvalds ino = dentry->d_inode->i_ino; 1381da177e4SLinus Torvalds if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 1391da177e4SLinus Torvalds break; 1401da177e4SLinus Torvalds filp->f_pos++; 1411da177e4SLinus Torvalds i++; 1421da177e4SLinus Torvalds /* fallthrough */ 1431da177e4SLinus Torvalds case 1: 1441da177e4SLinus Torvalds ino = parent_ino(dentry); 1451da177e4SLinus Torvalds if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1461da177e4SLinus Torvalds break; 1471da177e4SLinus Torvalds filp->f_pos++; 1481da177e4SLinus Torvalds i++; 1491da177e4SLinus Torvalds /* fallthrough */ 1501da177e4SLinus Torvalds default: 1511da177e4SLinus Torvalds spin_lock(&dcache_lock); 1521bfba4e8SAkinobu Mita if (filp->f_pos == 2) 1531bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1541bfba4e8SAkinobu Mita 1551da177e4SLinus Torvalds for (p=q->next; p != &dentry->d_subdirs; p=p->next) { 1561da177e4SLinus Torvalds struct dentry *next; 1575160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1581da177e4SLinus Torvalds if (d_unhashed(next) || !next->d_inode) 1591da177e4SLinus Torvalds continue; 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1620f8952c2SRonni Nielsen if (filldir(dirent, next->d_name.name, 1630f8952c2SRonni Nielsen next->d_name.len, filp->f_pos, 1640f8952c2SRonni Nielsen next->d_inode->i_ino, 1650f8952c2SRonni Nielsen dt_type(next->d_inode)) < 0) 1661da177e4SLinus Torvalds return 0; 1671da177e4SLinus Torvalds spin_lock(&dcache_lock); 1681da177e4SLinus Torvalds /* next is still alive */ 1691bfba4e8SAkinobu Mita list_move(q, p); 1701da177e4SLinus Torvalds p = q; 1711da177e4SLinus Torvalds filp->f_pos++; 1721da177e4SLinus Torvalds } 1731da177e4SLinus Torvalds spin_unlock(&dcache_lock); 1741da177e4SLinus Torvalds } 1751da177e4SLinus Torvalds return 0; 1761da177e4SLinus Torvalds } 1771da177e4SLinus Torvalds 1781da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1791da177e4SLinus Torvalds { 1801da177e4SLinus Torvalds return -EISDIR; 1811da177e4SLinus Torvalds } 1821da177e4SLinus Torvalds 1834b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1841da177e4SLinus Torvalds .open = dcache_dir_open, 1851da177e4SLinus Torvalds .release = dcache_dir_close, 1861da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1871da177e4SLinus Torvalds .read = generic_read_dir, 1881da177e4SLinus Torvalds .readdir = dcache_readdir, 1891b061d92SChristoph Hellwig .fsync = noop_fsync, 1901da177e4SLinus Torvalds }; 1911da177e4SLinus Torvalds 19292e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 1931da177e4SLinus Torvalds .lookup = simple_lookup, 1941da177e4SLinus Torvalds }; 1951da177e4SLinus Torvalds 196759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 197759b9775SHugh Dickins .statfs = simple_statfs, 198759b9775SHugh Dickins }; 199759b9775SHugh Dickins 2001da177e4SLinus Torvalds /* 2011da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 2021da177e4SLinus Torvalds * will never be mountable) 2031da177e4SLinus Torvalds */ 204454e2398SDavid Howells int get_sb_pseudo(struct file_system_type *fs_type, char *name, 205ee9b6d61SJosef 'Jeff' Sipek const struct super_operations *ops, unsigned long magic, 206454e2398SDavid Howells struct vfsmount *mnt) 2071da177e4SLinus Torvalds { 2081da177e4SLinus Torvalds struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); 2091da177e4SLinus Torvalds struct dentry *dentry; 2101da177e4SLinus Torvalds struct inode *root; 2111da177e4SLinus Torvalds struct qstr d_name = {.name = name, .len = strlen(name)}; 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds if (IS_ERR(s)) 214454e2398SDavid Howells return PTR_ERR(s); 2151da177e4SLinus Torvalds 2161da177e4SLinus Torvalds s->s_flags = MS_NOUSER; 21789a4eb4bSJeff Layton s->s_maxbytes = MAX_LFS_FILESIZE; 2183971e1a9SAlex Nixon s->s_blocksize = PAGE_SIZE; 2193971e1a9SAlex Nixon s->s_blocksize_bits = PAGE_SHIFT; 2201da177e4SLinus Torvalds s->s_magic = magic; 221759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2221da177e4SLinus Torvalds s->s_time_gran = 1; 2231da177e4SLinus Torvalds root = new_inode(s); 2241da177e4SLinus Torvalds if (!root) 2251da177e4SLinus Torvalds goto Enomem; 2261a1c9bb4SJeff Layton /* 2271a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2281a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2291a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2301a1c9bb4SJeff Layton */ 2311a1c9bb4SJeff Layton root->i_ino = 1; 2321da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2331da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 2341da177e4SLinus Torvalds dentry = d_alloc(NULL, &d_name); 2351da177e4SLinus Torvalds if (!dentry) { 2361da177e4SLinus Torvalds iput(root); 2371da177e4SLinus Torvalds goto Enomem; 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds dentry->d_sb = s; 2401da177e4SLinus Torvalds dentry->d_parent = dentry; 2411da177e4SLinus Torvalds d_instantiate(dentry, root); 2421da177e4SLinus Torvalds s->s_root = dentry; 2431da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 244a3ec947cSSukadev Bhattiprolu simple_set_mnt(mnt, s); 245a3ec947cSSukadev Bhattiprolu return 0; 2461da177e4SLinus Torvalds 2471da177e4SLinus Torvalds Enomem: 2486f5bbff9SAl Viro deactivate_locked_super(s); 249454e2398SDavid Howells return -ENOMEM; 2501da177e4SLinus Torvalds } 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2531da177e4SLinus Torvalds { 2541da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2551da177e4SLinus Torvalds 2561da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 257d8c76e6fSDave Hansen inc_nlink(inode); 2581da177e4SLinus Torvalds atomic_inc(&inode->i_count); 2591da177e4SLinus Torvalds dget(dentry); 2601da177e4SLinus Torvalds d_instantiate(dentry, inode); 2611da177e4SLinus Torvalds return 0; 2621da177e4SLinus Torvalds } 2631da177e4SLinus Torvalds 2641da177e4SLinus Torvalds static inline int simple_positive(struct dentry *dentry) 2651da177e4SLinus Torvalds { 2661da177e4SLinus Torvalds return dentry->d_inode && !d_unhashed(dentry); 2671da177e4SLinus Torvalds } 2681da177e4SLinus Torvalds 2691da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2701da177e4SLinus Torvalds { 2711da177e4SLinus Torvalds struct dentry *child; 2721da177e4SLinus Torvalds int ret = 0; 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds spin_lock(&dcache_lock); 2755160ee6fSEric Dumazet list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) 2761da177e4SLinus Torvalds if (simple_positive(child)) 2771da177e4SLinus Torvalds goto out; 2781da177e4SLinus Torvalds ret = 1; 2791da177e4SLinus Torvalds out: 2801da177e4SLinus Torvalds spin_unlock(&dcache_lock); 2811da177e4SLinus Torvalds return ret; 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 2841da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 2851da177e4SLinus Torvalds { 2861da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 2899a53c3a7SDave Hansen drop_nlink(inode); 2901da177e4SLinus Torvalds dput(dentry); 2911da177e4SLinus Torvalds return 0; 2921da177e4SLinus Torvalds } 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 2951da177e4SLinus Torvalds { 2961da177e4SLinus Torvalds if (!simple_empty(dentry)) 2971da177e4SLinus Torvalds return -ENOTEMPTY; 2981da177e4SLinus Torvalds 2999a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 3001da177e4SLinus Torvalds simple_unlink(dir, dentry); 3019a53c3a7SDave Hansen drop_nlink(dir); 3021da177e4SLinus Torvalds return 0; 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3061da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3071da177e4SLinus Torvalds { 3081da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3091da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3101da177e4SLinus Torvalds 3111da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3121da177e4SLinus Torvalds return -ENOTEMPTY; 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds if (new_dentry->d_inode) { 3151da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 3161da177e4SLinus Torvalds if (they_are_dirs) 3179a53c3a7SDave Hansen drop_nlink(old_dir); 3181da177e4SLinus Torvalds } else if (they_are_dirs) { 3199a53c3a7SDave Hansen drop_nlink(old_dir); 320d8c76e6fSDave Hansen inc_nlink(new_dir); 3211da177e4SLinus Torvalds } 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3241da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds return 0; 3271da177e4SLinus Torvalds } 3281da177e4SLinus Torvalds 3297bb46a67Snpiggin@suse.de /** 330eef2380cSChristoph Hellwig * simple_setattr - setattr for simple filesystem 3317bb46a67Snpiggin@suse.de * @dentry: dentry 3327bb46a67Snpiggin@suse.de * @iattr: iattr structure 3337bb46a67Snpiggin@suse.de * 3347bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3357bb46a67Snpiggin@suse.de * 336eef2380cSChristoph Hellwig * simple_setattr is a simple ->setattr implementation without a proper 337eef2380cSChristoph Hellwig * implementation of size changes. 338eef2380cSChristoph Hellwig * 339eef2380cSChristoph Hellwig * It can either be used for in-memory filesystems or special files 340eef2380cSChristoph Hellwig * on simple regular filesystems. Anything that needs to change on-disk 341eef2380cSChristoph Hellwig * or wire state on size changes needs its own setattr method. 3427bb46a67Snpiggin@suse.de */ 3437bb46a67Snpiggin@suse.de int simple_setattr(struct dentry *dentry, struct iattr *iattr) 3447bb46a67Snpiggin@suse.de { 3457bb46a67Snpiggin@suse.de struct inode *inode = dentry->d_inode; 3467bb46a67Snpiggin@suse.de int error; 3477bb46a67Snpiggin@suse.de 348eef2380cSChristoph Hellwig WARN_ON_ONCE(inode->i_op->truncate); 349eef2380cSChristoph Hellwig 3507bb46a67Snpiggin@suse.de error = inode_change_ok(inode, iattr); 3517bb46a67Snpiggin@suse.de if (error) 3527bb46a67Snpiggin@suse.de return error; 3537bb46a67Snpiggin@suse.de 3542c27c65eSChristoph Hellwig if (iattr->ia_valid & ATTR_SIZE) 3552c27c65eSChristoph Hellwig truncate_setsize(inode, iattr->ia_size); 3566a1a90adSChristoph Hellwig setattr_copy(inode, iattr); 357eef2380cSChristoph Hellwig mark_inode_dirty(inode); 358eef2380cSChristoph Hellwig return 0; 3597bb46a67Snpiggin@suse.de } 3607bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setattr); 3617bb46a67Snpiggin@suse.de 3621da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3631da177e4SLinus Torvalds { 364c0d92cbcSPekka J Enberg clear_highpage(page); 3651da177e4SLinus Torvalds flush_dcache_page(page); 3661da177e4SLinus Torvalds SetPageUptodate(page); 3671da177e4SLinus Torvalds unlock_page(page); 3681da177e4SLinus Torvalds return 0; 3691da177e4SLinus Torvalds } 3701da177e4SLinus Torvalds 371afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 372afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 373afddba49SNick Piggin struct page **pagep, void **fsdata) 374afddba49SNick Piggin { 375afddba49SNick Piggin struct page *page; 376afddba49SNick Piggin pgoff_t index; 377afddba49SNick Piggin 378afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 379afddba49SNick Piggin 38054566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 381afddba49SNick Piggin if (!page) 382afddba49SNick Piggin return -ENOMEM; 383afddba49SNick Piggin 384afddba49SNick Piggin *pagep = page; 385afddba49SNick Piggin 386193cf4b9SBoaz Harrosh if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { 387193cf4b9SBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 388193cf4b9SBoaz Harrosh 389193cf4b9SBoaz Harrosh zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); 390193cf4b9SBoaz Harrosh } 391193cf4b9SBoaz Harrosh return 0; 392afddba49SNick Piggin } 393afddba49SNick Piggin 394ad2a722fSBoaz Harrosh /** 395ad2a722fSBoaz Harrosh * simple_write_end - .write_end helper for non-block-device FSes 396ad2a722fSBoaz Harrosh * @available: See .write_end of address_space_operations 397ad2a722fSBoaz Harrosh * @file: " 398ad2a722fSBoaz Harrosh * @mapping: " 399ad2a722fSBoaz Harrosh * @pos: " 400ad2a722fSBoaz Harrosh * @len: " 401ad2a722fSBoaz Harrosh * @copied: " 402ad2a722fSBoaz Harrosh * @page: " 403ad2a722fSBoaz Harrosh * @fsdata: " 404ad2a722fSBoaz Harrosh * 405ad2a722fSBoaz Harrosh * simple_write_end does the minimum needed for updating a page after writing is 406ad2a722fSBoaz Harrosh * done. It has the same API signature as the .write_end of 407ad2a722fSBoaz Harrosh * address_space_operations vector. So it can just be set onto .write_end for 408ad2a722fSBoaz Harrosh * FSes that don't need any other processing. i_mutex is assumed to be held. 409ad2a722fSBoaz Harrosh * Block based filesystems should use generic_write_end(). 410ad2a722fSBoaz Harrosh * NOTE: Even though i_size might get updated by this function, mark_inode_dirty 411ad2a722fSBoaz Harrosh * is not called, so a filesystem that actually does store data in .write_inode 412ad2a722fSBoaz Harrosh * should extend on what's done here with a call to mark_inode_dirty() in the 413ad2a722fSBoaz Harrosh * case that i_size has changed. 414ad2a722fSBoaz Harrosh */ 415ad2a722fSBoaz Harrosh int simple_write_end(struct file *file, struct address_space *mapping, 416ad2a722fSBoaz Harrosh loff_t pos, unsigned len, unsigned copied, 417ad2a722fSBoaz Harrosh struct page *page, void *fsdata) 4181da177e4SLinus Torvalds { 4191da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 420ad2a722fSBoaz Harrosh loff_t last_pos = pos + copied; 421ad2a722fSBoaz Harrosh 422ad2a722fSBoaz Harrosh /* zero the stale part of the page if we did a short copy */ 423ad2a722fSBoaz Harrosh if (copied < len) { 424ad2a722fSBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 425ad2a722fSBoaz Harrosh 426ad2a722fSBoaz Harrosh zero_user(page, from + copied, len - copied); 427ad2a722fSBoaz Harrosh } 4281da177e4SLinus Torvalds 429955eff5aSNick Piggin if (!PageUptodate(page)) 430955eff5aSNick Piggin SetPageUptodate(page); 4311da177e4SLinus Torvalds /* 4321da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 4331b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 4341da177e4SLinus Torvalds */ 435ad2a722fSBoaz Harrosh if (last_pos > inode->i_size) 436ad2a722fSBoaz Harrosh i_size_write(inode, last_pos); 437ad2a722fSBoaz Harrosh 4381da177e4SLinus Torvalds set_page_dirty(page); 439afddba49SNick Piggin unlock_page(page); 440afddba49SNick Piggin page_cache_release(page); 441afddba49SNick Piggin 442afddba49SNick Piggin return copied; 443afddba49SNick Piggin } 444afddba49SNick Piggin 4451a1c9bb4SJeff Layton /* 4461a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4471a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4481a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4491a1c9bb4SJeff Layton */ 4507d683a09SRoberto Sassu int simple_fill_super(struct super_block *s, unsigned long magic, 4517d683a09SRoberto Sassu struct tree_descr *files) 4521da177e4SLinus Torvalds { 4531da177e4SLinus Torvalds struct inode *inode; 4541da177e4SLinus Torvalds struct dentry *root; 4551da177e4SLinus Torvalds struct dentry *dentry; 4561da177e4SLinus Torvalds int i; 4571da177e4SLinus Torvalds 4581da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 4591da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 4601da177e4SLinus Torvalds s->s_magic = magic; 461759b9775SHugh Dickins s->s_op = &simple_super_operations; 4621da177e4SLinus Torvalds s->s_time_gran = 1; 4631da177e4SLinus Torvalds 4641da177e4SLinus Torvalds inode = new_inode(s); 4651da177e4SLinus Torvalds if (!inode) 4661da177e4SLinus Torvalds return -ENOMEM; 4671a1c9bb4SJeff Layton /* 4681a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 4691a1c9bb4SJeff Layton * entry at index 1 4701a1c9bb4SJeff Layton */ 4711a1c9bb4SJeff Layton inode->i_ino = 1; 4721da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 4731da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4741da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4751da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 4767656f328SVincent Hanquez inode->i_nlink = 2; 4771da177e4SLinus Torvalds root = d_alloc_root(inode); 4781da177e4SLinus Torvalds if (!root) { 4791da177e4SLinus Torvalds iput(inode); 4801da177e4SLinus Torvalds return -ENOMEM; 4811da177e4SLinus Torvalds } 4821da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 4831da177e4SLinus Torvalds if (!files->name) 4841da177e4SLinus Torvalds continue; 4851a1c9bb4SJeff Layton 4861a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 4871a1c9bb4SJeff Layton if (unlikely(i == 1)) 4881a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 4891a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 4901a1c9bb4SJeff Layton s->s_type->name); 4911a1c9bb4SJeff Layton 4921da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 4931da177e4SLinus Torvalds if (!dentry) 4941da177e4SLinus Torvalds goto out; 4951da177e4SLinus Torvalds inode = new_inode(s); 4961da177e4SLinus Torvalds if (!inode) 4971da177e4SLinus Torvalds goto out; 4981da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 4991da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5001da177e4SLinus Torvalds inode->i_fop = files->ops; 5011da177e4SLinus Torvalds inode->i_ino = i; 5021da177e4SLinus Torvalds d_add(dentry, inode); 5031da177e4SLinus Torvalds } 5041da177e4SLinus Torvalds s->s_root = root; 5051da177e4SLinus Torvalds return 0; 5061da177e4SLinus Torvalds out: 5071da177e4SLinus Torvalds d_genocide(root); 5081da177e4SLinus Torvalds dput(root); 5091da177e4SLinus Torvalds return -ENOMEM; 5101da177e4SLinus Torvalds } 5111da177e4SLinus Torvalds 5121da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 5131da177e4SLinus Torvalds 5141f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 5151da177e4SLinus Torvalds { 5161da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 5171da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5181da177e4SLinus Torvalds if (unlikely(!*mount)) { 5191da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5201f5ce9e9STrond Myklebust mnt = vfs_kern_mount(type, 0, type->name, NULL); 5211da177e4SLinus Torvalds if (IS_ERR(mnt)) 5221da177e4SLinus Torvalds return PTR_ERR(mnt); 5231da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5241da177e4SLinus Torvalds if (!*mount) 5251da177e4SLinus Torvalds *mount = mnt; 5261da177e4SLinus Torvalds } 5271da177e4SLinus Torvalds mntget(*mount); 5281da177e4SLinus Torvalds ++*count; 5291da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5301da177e4SLinus Torvalds mntput(mnt); 5311da177e4SLinus Torvalds return 0; 5321da177e4SLinus Torvalds } 5331da177e4SLinus Torvalds 5341da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5351da177e4SLinus Torvalds { 5361da177e4SLinus Torvalds struct vfsmount *mnt; 5371da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5381da177e4SLinus Torvalds mnt = *mount; 5391da177e4SLinus Torvalds if (!--*count) 5401da177e4SLinus Torvalds *mount = NULL; 5411da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5421da177e4SLinus Torvalds mntput(mnt); 5431da177e4SLinus Torvalds } 5441da177e4SLinus Torvalds 5456d1029b5SAkinobu Mita /** 5466d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5476d1029b5SAkinobu Mita * @to: the user space buffer to read to 5486d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5496d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5506d1029b5SAkinobu Mita * @from: the buffer to read from 5516d1029b5SAkinobu Mita * @available: the size of the buffer 5526d1029b5SAkinobu Mita * 5536d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 5546d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 5556d1029b5SAkinobu Mita * 5566d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5576d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5586d1029b5SAkinobu Mita **/ 5591da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 5601da177e4SLinus Torvalds const void *from, size_t available) 5611da177e4SLinus Torvalds { 5621da177e4SLinus Torvalds loff_t pos = *ppos; 56314be2746SSteven Rostedt size_t ret; 56414be2746SSteven Rostedt 5651da177e4SLinus Torvalds if (pos < 0) 5661da177e4SLinus Torvalds return -EINVAL; 56714be2746SSteven Rostedt if (pos >= available || !count) 5681da177e4SLinus Torvalds return 0; 5691da177e4SLinus Torvalds if (count > available - pos) 5701da177e4SLinus Torvalds count = available - pos; 57114be2746SSteven Rostedt ret = copy_to_user(to, from + pos, count); 57214be2746SSteven Rostedt if (ret == count) 5731da177e4SLinus Torvalds return -EFAULT; 57414be2746SSteven Rostedt count -= ret; 5751da177e4SLinus Torvalds *ppos = pos + count; 5761da177e4SLinus Torvalds return count; 5771da177e4SLinus Torvalds } 5781da177e4SLinus Torvalds 5796d1029b5SAkinobu Mita /** 5806a727b43SJiri Slaby * simple_write_to_buffer - copy data from user space to the buffer 5816a727b43SJiri Slaby * @to: the buffer to write to 5826a727b43SJiri Slaby * @available: the size of the buffer 5836a727b43SJiri Slaby * @ppos: the current position in the buffer 5846a727b43SJiri Slaby * @from: the user space buffer to read from 5856a727b43SJiri Slaby * @count: the maximum number of bytes to read 5866a727b43SJiri Slaby * 5876a727b43SJiri Slaby * The simple_write_to_buffer() function reads up to @count bytes from the user 5886a727b43SJiri Slaby * space address starting at @from into the buffer @to at offset @ppos. 5896a727b43SJiri Slaby * 5906a727b43SJiri Slaby * On success, the number of bytes written is returned and the offset @ppos is 5916a727b43SJiri Slaby * advanced by this number, or negative value is returned on error. 5926a727b43SJiri Slaby **/ 5936a727b43SJiri Slaby ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, 5946a727b43SJiri Slaby const void __user *from, size_t count) 5956a727b43SJiri Slaby { 5966a727b43SJiri Slaby loff_t pos = *ppos; 5976a727b43SJiri Slaby size_t res; 5986a727b43SJiri Slaby 5996a727b43SJiri Slaby if (pos < 0) 6006a727b43SJiri Slaby return -EINVAL; 6016a727b43SJiri Slaby if (pos >= available || !count) 6026a727b43SJiri Slaby return 0; 6036a727b43SJiri Slaby if (count > available - pos) 6046a727b43SJiri Slaby count = available - pos; 6056a727b43SJiri Slaby res = copy_from_user(to + pos, from, count); 6066a727b43SJiri Slaby if (res == count) 6076a727b43SJiri Slaby return -EFAULT; 6086a727b43SJiri Slaby count -= res; 6096a727b43SJiri Slaby *ppos = pos + count; 6106a727b43SJiri Slaby return count; 6116a727b43SJiri Slaby } 6126a727b43SJiri Slaby 6136a727b43SJiri Slaby /** 6146d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 6156d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 6166d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 6176d1029b5SAkinobu Mita * @ppos: the current position in the buffer 6186d1029b5SAkinobu Mita * @from: the buffer to read from 6196d1029b5SAkinobu Mita * @available: the size of the buffer 6206d1029b5SAkinobu Mita * 6216d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 6226d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 6236d1029b5SAkinobu Mita * 6246d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6256d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6266d1029b5SAkinobu Mita **/ 62793b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 62893b07113SAkinobu Mita const void *from, size_t available) 62993b07113SAkinobu Mita { 63093b07113SAkinobu Mita loff_t pos = *ppos; 63193b07113SAkinobu Mita 63293b07113SAkinobu Mita if (pos < 0) 63393b07113SAkinobu Mita return -EINVAL; 63493b07113SAkinobu Mita if (pos >= available) 63593b07113SAkinobu Mita return 0; 63693b07113SAkinobu Mita if (count > available - pos) 63793b07113SAkinobu Mita count = available - pos; 63893b07113SAkinobu Mita memcpy(to, from + pos, count); 63993b07113SAkinobu Mita *ppos = pos + count; 64093b07113SAkinobu Mita 64193b07113SAkinobu Mita return count; 64293b07113SAkinobu Mita } 64393b07113SAkinobu Mita 6441da177e4SLinus Torvalds /* 6451da177e4SLinus Torvalds * Transaction based IO. 6461da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 6471da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 6481da177e4SLinus Torvalds * file-local buffer. 6491da177e4SLinus Torvalds */ 65076791ab2SIngo Molnar 65176791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 65276791ab2SIngo Molnar { 65376791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 65476791ab2SIngo Molnar 65576791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 65676791ab2SIngo Molnar 65776791ab2SIngo Molnar /* 65876791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 65976791ab2SIngo Molnar * ar->data is ready for reading. 66076791ab2SIngo Molnar */ 66176791ab2SIngo Molnar smp_mb(); 66276791ab2SIngo Molnar ar->size = n; 66376791ab2SIngo Molnar } 66476791ab2SIngo Molnar 6651da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 6661da177e4SLinus Torvalds { 6671da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 6681da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 6691da177e4SLinus Torvalds 6701da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 6711da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 6721da177e4SLinus Torvalds 6731da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 6741da177e4SLinus Torvalds if (!ar) 6751da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 6781da177e4SLinus Torvalds 6791da177e4SLinus Torvalds /* only one write allowed per open */ 6801da177e4SLinus Torvalds if (file->private_data) { 6811da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6821da177e4SLinus Torvalds free_page((unsigned long)ar); 6831da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 6841da177e4SLinus Torvalds } 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds file->private_data = ar; 6871da177e4SLinus Torvalds 6881da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 6891da177e4SLinus Torvalds 6901da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 6911da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 6921da177e4SLinus Torvalds 6931da177e4SLinus Torvalds return ar->data; 6941da177e4SLinus Torvalds } 6951da177e4SLinus Torvalds 6961da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 6971da177e4SLinus Torvalds { 6981da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 6991da177e4SLinus Torvalds 7001da177e4SLinus Torvalds if (!ar) 7011da177e4SLinus Torvalds return 0; 7021da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 7031da177e4SLinus Torvalds } 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 7061da177e4SLinus Torvalds { 7071da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 7081da177e4SLinus Torvalds return 0; 7091da177e4SLinus Torvalds } 7101da177e4SLinus Torvalds 711acaefc25SArnd Bergmann /* Simple attribute files */ 712acaefc25SArnd Bergmann 713acaefc25SArnd Bergmann struct simple_attr { 7148b88b099SChristoph Hellwig int (*get)(void *, u64 *); 7158b88b099SChristoph Hellwig int (*set)(void *, u64); 716acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 717acaefc25SArnd Bergmann char set_buf[24]; 718acaefc25SArnd Bergmann void *data; 719acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 7207cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 721acaefc25SArnd Bergmann }; 722acaefc25SArnd Bergmann 723acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 724acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 725acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 7268b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 727acaefc25SArnd Bergmann const char *fmt) 728acaefc25SArnd Bergmann { 729acaefc25SArnd Bergmann struct simple_attr *attr; 730acaefc25SArnd Bergmann 731acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 732acaefc25SArnd Bergmann if (!attr) 733acaefc25SArnd Bergmann return -ENOMEM; 734acaefc25SArnd Bergmann 735acaefc25SArnd Bergmann attr->get = get; 736acaefc25SArnd Bergmann attr->set = set; 7378e18e294STheodore Ts'o attr->data = inode->i_private; 738acaefc25SArnd Bergmann attr->fmt = fmt; 7397cf34c76SIngo Molnar mutex_init(&attr->mutex); 740acaefc25SArnd Bergmann 741acaefc25SArnd Bergmann file->private_data = attr; 742acaefc25SArnd Bergmann 743acaefc25SArnd Bergmann return nonseekable_open(inode, file); 744acaefc25SArnd Bergmann } 745acaefc25SArnd Bergmann 74674bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 747acaefc25SArnd Bergmann { 748acaefc25SArnd Bergmann kfree(file->private_data); 749acaefc25SArnd Bergmann return 0; 750acaefc25SArnd Bergmann } 751acaefc25SArnd Bergmann 752acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 753acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 754acaefc25SArnd Bergmann size_t len, loff_t *ppos) 755acaefc25SArnd Bergmann { 756acaefc25SArnd Bergmann struct simple_attr *attr; 757acaefc25SArnd Bergmann size_t size; 758acaefc25SArnd Bergmann ssize_t ret; 759acaefc25SArnd Bergmann 760acaefc25SArnd Bergmann attr = file->private_data; 761acaefc25SArnd Bergmann 762acaefc25SArnd Bergmann if (!attr->get) 763acaefc25SArnd Bergmann return -EACCES; 764acaefc25SArnd Bergmann 7659261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 7669261303aSChristoph Hellwig if (ret) 7679261303aSChristoph Hellwig return ret; 7689261303aSChristoph Hellwig 7698b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 770acaefc25SArnd Bergmann size = strlen(attr->get_buf); 7718b88b099SChristoph Hellwig } else { /* first read */ 7728b88b099SChristoph Hellwig u64 val; 7738b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 7748b88b099SChristoph Hellwig if (ret) 7758b88b099SChristoph Hellwig goto out; 7768b88b099SChristoph Hellwig 777acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 7788b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 7798b88b099SChristoph Hellwig } 780acaefc25SArnd Bergmann 781acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 7828b88b099SChristoph Hellwig out: 7837cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 784acaefc25SArnd Bergmann return ret; 785acaefc25SArnd Bergmann } 786acaefc25SArnd Bergmann 787acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 788acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 789acaefc25SArnd Bergmann size_t len, loff_t *ppos) 790acaefc25SArnd Bergmann { 791acaefc25SArnd Bergmann struct simple_attr *attr; 792acaefc25SArnd Bergmann u64 val; 793acaefc25SArnd Bergmann size_t size; 794acaefc25SArnd Bergmann ssize_t ret; 795acaefc25SArnd Bergmann 796acaefc25SArnd Bergmann attr = file->private_data; 797acaefc25SArnd Bergmann if (!attr->set) 798acaefc25SArnd Bergmann return -EACCES; 799acaefc25SArnd Bergmann 8009261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8019261303aSChristoph Hellwig if (ret) 8029261303aSChristoph Hellwig return ret; 8039261303aSChristoph Hellwig 804acaefc25SArnd Bergmann ret = -EFAULT; 805acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 806acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 807acaefc25SArnd Bergmann goto out; 808acaefc25SArnd Bergmann 809acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 810acaefc25SArnd Bergmann val = simple_strtol(attr->set_buf, NULL, 0); 81105cc0ceeSWu Fengguang ret = attr->set(attr->data, val); 81205cc0ceeSWu Fengguang if (ret == 0) 81305cc0ceeSWu Fengguang ret = len; /* on success, claim we got the whole input */ 814acaefc25SArnd Bergmann out: 8157cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 816acaefc25SArnd Bergmann return ret; 817acaefc25SArnd Bergmann } 818acaefc25SArnd Bergmann 8192596110aSChristoph Hellwig /** 8202596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 8212596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8222596110aSChristoph Hellwig * @fid: file handle to convert 8232596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8242596110aSChristoph Hellwig * @fh_type: type of file handle 8252596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8262596110aSChristoph Hellwig * 8272596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8282596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8292596110aSChristoph Hellwig * inode for the object specified in the file handle. 8302596110aSChristoph Hellwig */ 8312596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 8322596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8332596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8342596110aSChristoph Hellwig { 8352596110aSChristoph Hellwig struct inode *inode = NULL; 8362596110aSChristoph Hellwig 8372596110aSChristoph Hellwig if (fh_len < 2) 8382596110aSChristoph Hellwig return NULL; 8392596110aSChristoph Hellwig 8402596110aSChristoph Hellwig switch (fh_type) { 8412596110aSChristoph Hellwig case FILEID_INO32_GEN: 8422596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8432596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 8442596110aSChristoph Hellwig break; 8452596110aSChristoph Hellwig } 8462596110aSChristoph Hellwig 8474ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8482596110aSChristoph Hellwig } 8492596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 8502596110aSChristoph Hellwig 8512596110aSChristoph Hellwig /** 8522596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_parent export operation 8532596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8542596110aSChristoph Hellwig * @fid: file handle to convert 8552596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8562596110aSChristoph Hellwig * @fh_type: type of file handle 8572596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8582596110aSChristoph Hellwig * 8592596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8602596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8612596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 8622596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 8632596110aSChristoph Hellwig */ 8642596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 8652596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8662596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8672596110aSChristoph Hellwig { 8682596110aSChristoph Hellwig struct inode *inode = NULL; 8692596110aSChristoph Hellwig 8702596110aSChristoph Hellwig if (fh_len <= 2) 8712596110aSChristoph Hellwig return NULL; 8722596110aSChristoph Hellwig 8732596110aSChristoph Hellwig switch (fh_type) { 8742596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8752596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 8762596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 8772596110aSChristoph Hellwig break; 8782596110aSChristoph Hellwig } 8792596110aSChristoph Hellwig 8804ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8812596110aSChristoph Hellwig } 8822596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 8832596110aSChristoph Hellwig 8841b061d92SChristoph Hellwig /** 8851b061d92SChristoph Hellwig * generic_file_fsync - generic fsync implementation for simple filesystems 8861b061d92SChristoph Hellwig * @file: file to synchronize 8871b061d92SChristoph Hellwig * @datasync: only synchronize essential metadata if true 8881b061d92SChristoph Hellwig * 8891b061d92SChristoph Hellwig * This is a generic implementation of the fsync method for simple 8901b061d92SChristoph Hellwig * filesystems which track all non-inode metadata in the buffers list 8911b061d92SChristoph Hellwig * hanging off the address_space structure. 8921b061d92SChristoph Hellwig */ 8931b061d92SChristoph Hellwig int generic_file_fsync(struct file *file, int datasync) 894d5aacad5SAl Viro { 8957ea80859SChristoph Hellwig struct inode *inode = file->f_mapping->host; 896d5aacad5SAl Viro int err; 897d5aacad5SAl Viro int ret; 898d5aacad5SAl Viro 899d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 900d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 901d5aacad5SAl Viro return ret; 902d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 903d5aacad5SAl Viro return ret; 904d5aacad5SAl Viro 905c3765016SChristoph Hellwig err = sync_inode_metadata(inode, 1); 906d5aacad5SAl Viro if (ret == 0) 907d5aacad5SAl Viro ret = err; 908d5aacad5SAl Viro return ret; 909d5aacad5SAl Viro } 9101b061d92SChristoph Hellwig EXPORT_SYMBOL(generic_file_fsync); 9111b061d92SChristoph Hellwig 91230ca22c7SPatrick J. LoPresti /** 91330ca22c7SPatrick J. LoPresti * generic_check_addressable - Check addressability of file system 91430ca22c7SPatrick J. LoPresti * @blocksize_bits: log of file system block size 91530ca22c7SPatrick J. LoPresti * @num_blocks: number of blocks in file system 91630ca22c7SPatrick J. LoPresti * 91730ca22c7SPatrick J. LoPresti * Determine whether a file system with @num_blocks blocks (and a 91830ca22c7SPatrick J. LoPresti * block size of 2**@blocksize_bits) is addressable by the sector_t 91930ca22c7SPatrick J. LoPresti * and page cache of the system. Return 0 if so and -EFBIG otherwise. 92030ca22c7SPatrick J. LoPresti */ 92130ca22c7SPatrick J. LoPresti int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) 92230ca22c7SPatrick J. LoPresti { 92330ca22c7SPatrick J. LoPresti u64 last_fs_block = num_blocks - 1; 924a33f13efSJoel Becker u64 last_fs_page = 925a33f13efSJoel Becker last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); 92630ca22c7SPatrick J. LoPresti 92730ca22c7SPatrick J. LoPresti if (unlikely(num_blocks == 0)) 92830ca22c7SPatrick J. LoPresti return 0; 92930ca22c7SPatrick J. LoPresti 93030ca22c7SPatrick J. LoPresti if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) 93130ca22c7SPatrick J. LoPresti return -EINVAL; 93230ca22c7SPatrick J. LoPresti 933a33f13efSJoel Becker if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || 934a33f13efSJoel Becker (last_fs_page > (pgoff_t)(~0ULL))) { 93530ca22c7SPatrick J. LoPresti return -EFBIG; 93630ca22c7SPatrick J. LoPresti } 93730ca22c7SPatrick J. LoPresti return 0; 93830ca22c7SPatrick J. LoPresti } 93930ca22c7SPatrick J. LoPresti EXPORT_SYMBOL(generic_check_addressable); 94030ca22c7SPatrick J. LoPresti 9411b061d92SChristoph Hellwig /* 9421b061d92SChristoph Hellwig * No-op implementation of ->fsync for in-memory filesystems. 9431b061d92SChristoph Hellwig */ 9441b061d92SChristoph Hellwig int noop_fsync(struct file *file, int datasync) 9451b061d92SChristoph Hellwig { 9461b061d92SChristoph Hellwig return 0; 9471b061d92SChristoph Hellwig } 948d5aacad5SAl Viro 9491da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_close); 9501da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_lseek); 9511da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_open); 9521da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_readdir); 9531da177e4SLinus Torvalds EXPORT_SYMBOL(generic_read_dir); 9541da177e4SLinus Torvalds EXPORT_SYMBOL(get_sb_pseudo); 955afddba49SNick Piggin EXPORT_SYMBOL(simple_write_begin); 956afddba49SNick Piggin EXPORT_SYMBOL(simple_write_end); 9571da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_inode_operations); 9581da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_operations); 9591da177e4SLinus Torvalds EXPORT_SYMBOL(simple_empty); 9601da177e4SLinus Torvalds EXPORT_SYMBOL(simple_fill_super); 9611da177e4SLinus Torvalds EXPORT_SYMBOL(simple_getattr); 9621da177e4SLinus Torvalds EXPORT_SYMBOL(simple_link); 9631da177e4SLinus Torvalds EXPORT_SYMBOL(simple_lookup); 9641da177e4SLinus Torvalds EXPORT_SYMBOL(simple_pin_fs); 9651da177e4SLinus Torvalds EXPORT_SYMBOL(simple_readpage); 9661da177e4SLinus Torvalds EXPORT_SYMBOL(simple_release_fs); 9671da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rename); 9681da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rmdir); 9691da177e4SLinus Torvalds EXPORT_SYMBOL(simple_statfs); 9701b061d92SChristoph Hellwig EXPORT_SYMBOL(noop_fsync); 9711da177e4SLinus Torvalds EXPORT_SYMBOL(simple_unlink); 9721da177e4SLinus Torvalds EXPORT_SYMBOL(simple_read_from_buffer); 9736a727b43SJiri Slaby EXPORT_SYMBOL(simple_write_to_buffer); 97493b07113SAkinobu Mita EXPORT_SYMBOL(memory_read_from_buffer); 97576791ab2SIngo Molnar EXPORT_SYMBOL(simple_transaction_set); 9761da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_get); 9771da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_read); 9781da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_release); 979acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_open); 98074bedc4dSChristoph Hellwig EXPORT_SYMBOL_GPL(simple_attr_release); 981acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_read); 982acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_write); 983