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 /** 3307bb46a67Snpiggin@suse.de * simple_setsize - handle core mm and vfs requirements for file size change 3317bb46a67Snpiggin@suse.de * @inode: inode 3327bb46a67Snpiggin@suse.de * @newsize: new file size 3337bb46a67Snpiggin@suse.de * 3347bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3357bb46a67Snpiggin@suse.de * 3367bb46a67Snpiggin@suse.de * simple_setsize must be called with inode_mutex held. 3377bb46a67Snpiggin@suse.de * 3387bb46a67Snpiggin@suse.de * simple_setsize will check that the requested new size is OK (see 3397bb46a67Snpiggin@suse.de * inode_newsize_ok), and then will perform the necessary i_size update 3407bb46a67Snpiggin@suse.de * and pagecache truncation (if necessary). It will be typically be called 3417bb46a67Snpiggin@suse.de * from the filesystem's setattr function when ATTR_SIZE is passed in. 3427bb46a67Snpiggin@suse.de * 3437bb46a67Snpiggin@suse.de * The inode itself must have correct permissions and attributes to allow 3447bb46a67Snpiggin@suse.de * i_size to be changed, this function then just checks that the new size 3457bb46a67Snpiggin@suse.de * requested is valid. 3467bb46a67Snpiggin@suse.de * 3477bb46a67Snpiggin@suse.de * In the case of simple in-memory filesystems with inodes stored solely 3487bb46a67Snpiggin@suse.de * in the inode cache, and file data in the pagecache, nothing more needs 3497bb46a67Snpiggin@suse.de * to be done to satisfy a truncate request. Filesystems with on-disk 3507bb46a67Snpiggin@suse.de * blocks for example will need to free them in the case of truncate, in 3517bb46a67Snpiggin@suse.de * that case it may be easier not to use simple_setsize (but each of its 3527bb46a67Snpiggin@suse.de * components will likely be required at some point to update pagecache 3537bb46a67Snpiggin@suse.de * and inode etc). 3547bb46a67Snpiggin@suse.de */ 3557bb46a67Snpiggin@suse.de int simple_setsize(struct inode *inode, loff_t newsize) 3567bb46a67Snpiggin@suse.de { 3577bb46a67Snpiggin@suse.de loff_t oldsize; 3587bb46a67Snpiggin@suse.de int error; 3597bb46a67Snpiggin@suse.de 3607bb46a67Snpiggin@suse.de error = inode_newsize_ok(inode, newsize); 3617bb46a67Snpiggin@suse.de if (error) 3627bb46a67Snpiggin@suse.de return error; 3637bb46a67Snpiggin@suse.de 3647bb46a67Snpiggin@suse.de oldsize = inode->i_size; 3657bb46a67Snpiggin@suse.de i_size_write(inode, newsize); 3667bb46a67Snpiggin@suse.de truncate_pagecache(inode, oldsize, newsize); 3677bb46a67Snpiggin@suse.de 3687bb46a67Snpiggin@suse.de return error; 3697bb46a67Snpiggin@suse.de } 3707bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setsize); 3717bb46a67Snpiggin@suse.de 3727bb46a67Snpiggin@suse.de /** 373eef2380cSChristoph Hellwig * simple_setattr - setattr for simple filesystem 3747bb46a67Snpiggin@suse.de * @dentry: dentry 3757bb46a67Snpiggin@suse.de * @iattr: iattr structure 3767bb46a67Snpiggin@suse.de * 3777bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3787bb46a67Snpiggin@suse.de * 379eef2380cSChristoph Hellwig * simple_setattr is a simple ->setattr implementation without a proper 380eef2380cSChristoph Hellwig * implementation of size changes. 381eef2380cSChristoph Hellwig * 382eef2380cSChristoph Hellwig * It can either be used for in-memory filesystems or special files 383eef2380cSChristoph Hellwig * on simple regular filesystems. Anything that needs to change on-disk 384eef2380cSChristoph Hellwig * or wire state on size changes needs its own setattr method. 3857bb46a67Snpiggin@suse.de */ 3867bb46a67Snpiggin@suse.de int simple_setattr(struct dentry *dentry, struct iattr *iattr) 3877bb46a67Snpiggin@suse.de { 3887bb46a67Snpiggin@suse.de struct inode *inode = dentry->d_inode; 3897bb46a67Snpiggin@suse.de int error; 3907bb46a67Snpiggin@suse.de 391eef2380cSChristoph Hellwig WARN_ON_ONCE(inode->i_op->truncate); 392eef2380cSChristoph Hellwig 3937bb46a67Snpiggin@suse.de error = inode_change_ok(inode, iattr); 3947bb46a67Snpiggin@suse.de if (error) 3957bb46a67Snpiggin@suse.de return error; 3967bb46a67Snpiggin@suse.de 3977bb46a67Snpiggin@suse.de if (iattr->ia_valid & ATTR_SIZE) { 3987bb46a67Snpiggin@suse.de error = simple_setsize(inode, iattr->ia_size); 3997bb46a67Snpiggin@suse.de if (error) 4007bb46a67Snpiggin@suse.de return error; 4017bb46a67Snpiggin@suse.de } 4027bb46a67Snpiggin@suse.de 4036a1a90adSChristoph Hellwig setattr_copy(inode, iattr); 404eef2380cSChristoph Hellwig mark_inode_dirty(inode); 405eef2380cSChristoph Hellwig return 0; 4067bb46a67Snpiggin@suse.de } 4077bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setattr); 4087bb46a67Snpiggin@suse.de 4091da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 4101da177e4SLinus Torvalds { 411c0d92cbcSPekka J Enberg clear_highpage(page); 4121da177e4SLinus Torvalds flush_dcache_page(page); 4131da177e4SLinus Torvalds SetPageUptodate(page); 4141da177e4SLinus Torvalds unlock_page(page); 4151da177e4SLinus Torvalds return 0; 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds 418afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 419afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 420afddba49SNick Piggin struct page **pagep, void **fsdata) 421afddba49SNick Piggin { 422afddba49SNick Piggin struct page *page; 423afddba49SNick Piggin pgoff_t index; 424afddba49SNick Piggin 425afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 426afddba49SNick Piggin 42754566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 428afddba49SNick Piggin if (!page) 429afddba49SNick Piggin return -ENOMEM; 430afddba49SNick Piggin 431afddba49SNick Piggin *pagep = page; 432afddba49SNick Piggin 433193cf4b9SBoaz Harrosh if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { 434193cf4b9SBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 435193cf4b9SBoaz Harrosh 436193cf4b9SBoaz Harrosh zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); 437193cf4b9SBoaz Harrosh } 438193cf4b9SBoaz Harrosh return 0; 439afddba49SNick Piggin } 440afddba49SNick Piggin 441ad2a722fSBoaz Harrosh /** 442ad2a722fSBoaz Harrosh * simple_write_end - .write_end helper for non-block-device FSes 443ad2a722fSBoaz Harrosh * @available: See .write_end of address_space_operations 444ad2a722fSBoaz Harrosh * @file: " 445ad2a722fSBoaz Harrosh * @mapping: " 446ad2a722fSBoaz Harrosh * @pos: " 447ad2a722fSBoaz Harrosh * @len: " 448ad2a722fSBoaz Harrosh * @copied: " 449ad2a722fSBoaz Harrosh * @page: " 450ad2a722fSBoaz Harrosh * @fsdata: " 451ad2a722fSBoaz Harrosh * 452ad2a722fSBoaz Harrosh * simple_write_end does the minimum needed for updating a page after writing is 453ad2a722fSBoaz Harrosh * done. It has the same API signature as the .write_end of 454ad2a722fSBoaz Harrosh * address_space_operations vector. So it can just be set onto .write_end for 455ad2a722fSBoaz Harrosh * FSes that don't need any other processing. i_mutex is assumed to be held. 456ad2a722fSBoaz Harrosh * Block based filesystems should use generic_write_end(). 457ad2a722fSBoaz Harrosh * NOTE: Even though i_size might get updated by this function, mark_inode_dirty 458ad2a722fSBoaz Harrosh * is not called, so a filesystem that actually does store data in .write_inode 459ad2a722fSBoaz Harrosh * should extend on what's done here with a call to mark_inode_dirty() in the 460ad2a722fSBoaz Harrosh * case that i_size has changed. 461ad2a722fSBoaz Harrosh */ 462ad2a722fSBoaz Harrosh int simple_write_end(struct file *file, struct address_space *mapping, 463ad2a722fSBoaz Harrosh loff_t pos, unsigned len, unsigned copied, 464ad2a722fSBoaz Harrosh struct page *page, void *fsdata) 4651da177e4SLinus Torvalds { 4661da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 467ad2a722fSBoaz Harrosh loff_t last_pos = pos + copied; 468ad2a722fSBoaz Harrosh 469ad2a722fSBoaz Harrosh /* zero the stale part of the page if we did a short copy */ 470ad2a722fSBoaz Harrosh if (copied < len) { 471ad2a722fSBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 472ad2a722fSBoaz Harrosh 473ad2a722fSBoaz Harrosh zero_user(page, from + copied, len - copied); 474ad2a722fSBoaz Harrosh } 4751da177e4SLinus Torvalds 476955eff5aSNick Piggin if (!PageUptodate(page)) 477955eff5aSNick Piggin SetPageUptodate(page); 4781da177e4SLinus Torvalds /* 4791da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 4801b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 4811da177e4SLinus Torvalds */ 482ad2a722fSBoaz Harrosh if (last_pos > inode->i_size) 483ad2a722fSBoaz Harrosh i_size_write(inode, last_pos); 484ad2a722fSBoaz Harrosh 4851da177e4SLinus Torvalds set_page_dirty(page); 486afddba49SNick Piggin unlock_page(page); 487afddba49SNick Piggin page_cache_release(page); 488afddba49SNick Piggin 489afddba49SNick Piggin return copied; 490afddba49SNick Piggin } 491afddba49SNick Piggin 4921a1c9bb4SJeff Layton /* 4931a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4941a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4951a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4961a1c9bb4SJeff Layton */ 4977d683a09SRoberto Sassu int simple_fill_super(struct super_block *s, unsigned long magic, 4987d683a09SRoberto Sassu struct tree_descr *files) 4991da177e4SLinus Torvalds { 5001da177e4SLinus Torvalds struct inode *inode; 5011da177e4SLinus Torvalds struct dentry *root; 5021da177e4SLinus Torvalds struct dentry *dentry; 5031da177e4SLinus Torvalds int i; 5041da177e4SLinus Torvalds 5051da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 5061da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 5071da177e4SLinus Torvalds s->s_magic = magic; 508759b9775SHugh Dickins s->s_op = &simple_super_operations; 5091da177e4SLinus Torvalds s->s_time_gran = 1; 5101da177e4SLinus Torvalds 5111da177e4SLinus Torvalds inode = new_inode(s); 5121da177e4SLinus Torvalds if (!inode) 5131da177e4SLinus Torvalds return -ENOMEM; 5141a1c9bb4SJeff Layton /* 5151a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 5161a1c9bb4SJeff Layton * entry at index 1 5171a1c9bb4SJeff Layton */ 5181a1c9bb4SJeff Layton inode->i_ino = 1; 5191da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 5201da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5211da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 5221da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 5237656f328SVincent Hanquez inode->i_nlink = 2; 5241da177e4SLinus Torvalds root = d_alloc_root(inode); 5251da177e4SLinus Torvalds if (!root) { 5261da177e4SLinus Torvalds iput(inode); 5271da177e4SLinus Torvalds return -ENOMEM; 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 5301da177e4SLinus Torvalds if (!files->name) 5311da177e4SLinus Torvalds continue; 5321a1c9bb4SJeff Layton 5331a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 5341a1c9bb4SJeff Layton if (unlikely(i == 1)) 5351a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 5361a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 5371a1c9bb4SJeff Layton s->s_type->name); 5381a1c9bb4SJeff Layton 5391da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 5401da177e4SLinus Torvalds if (!dentry) 5411da177e4SLinus Torvalds goto out; 5421da177e4SLinus Torvalds inode = new_inode(s); 5431da177e4SLinus Torvalds if (!inode) 5441da177e4SLinus Torvalds goto out; 5451da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 5461da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5471da177e4SLinus Torvalds inode->i_fop = files->ops; 5481da177e4SLinus Torvalds inode->i_ino = i; 5491da177e4SLinus Torvalds d_add(dentry, inode); 5501da177e4SLinus Torvalds } 5511da177e4SLinus Torvalds s->s_root = root; 5521da177e4SLinus Torvalds return 0; 5531da177e4SLinus Torvalds out: 5541da177e4SLinus Torvalds d_genocide(root); 5551da177e4SLinus Torvalds dput(root); 5561da177e4SLinus Torvalds return -ENOMEM; 5571da177e4SLinus Torvalds } 5581da177e4SLinus Torvalds 5591da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 5601da177e4SLinus Torvalds 5611f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 5621da177e4SLinus Torvalds { 5631da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 5641da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5651da177e4SLinus Torvalds if (unlikely(!*mount)) { 5661da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5671f5ce9e9STrond Myklebust mnt = vfs_kern_mount(type, 0, type->name, NULL); 5681da177e4SLinus Torvalds if (IS_ERR(mnt)) 5691da177e4SLinus Torvalds return PTR_ERR(mnt); 5701da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5711da177e4SLinus Torvalds if (!*mount) 5721da177e4SLinus Torvalds *mount = mnt; 5731da177e4SLinus Torvalds } 5741da177e4SLinus Torvalds mntget(*mount); 5751da177e4SLinus Torvalds ++*count; 5761da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5771da177e4SLinus Torvalds mntput(mnt); 5781da177e4SLinus Torvalds return 0; 5791da177e4SLinus Torvalds } 5801da177e4SLinus Torvalds 5811da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5821da177e4SLinus Torvalds { 5831da177e4SLinus Torvalds struct vfsmount *mnt; 5841da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5851da177e4SLinus Torvalds mnt = *mount; 5861da177e4SLinus Torvalds if (!--*count) 5871da177e4SLinus Torvalds *mount = NULL; 5881da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5891da177e4SLinus Torvalds mntput(mnt); 5901da177e4SLinus Torvalds } 5911da177e4SLinus Torvalds 5926d1029b5SAkinobu Mita /** 5936d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5946d1029b5SAkinobu Mita * @to: the user space buffer to read to 5956d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5966d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5976d1029b5SAkinobu Mita * @from: the buffer to read from 5986d1029b5SAkinobu Mita * @available: the size of the buffer 5996d1029b5SAkinobu Mita * 6006d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 6016d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 6026d1029b5SAkinobu Mita * 6036d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6046d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6056d1029b5SAkinobu Mita **/ 6061da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 6071da177e4SLinus Torvalds const void *from, size_t available) 6081da177e4SLinus Torvalds { 6091da177e4SLinus Torvalds loff_t pos = *ppos; 61014be2746SSteven Rostedt size_t ret; 61114be2746SSteven Rostedt 6121da177e4SLinus Torvalds if (pos < 0) 6131da177e4SLinus Torvalds return -EINVAL; 61414be2746SSteven Rostedt if (pos >= available || !count) 6151da177e4SLinus Torvalds return 0; 6161da177e4SLinus Torvalds if (count > available - pos) 6171da177e4SLinus Torvalds count = available - pos; 61814be2746SSteven Rostedt ret = copy_to_user(to, from + pos, count); 61914be2746SSteven Rostedt if (ret == count) 6201da177e4SLinus Torvalds return -EFAULT; 62114be2746SSteven Rostedt count -= ret; 6221da177e4SLinus Torvalds *ppos = pos + count; 6231da177e4SLinus Torvalds return count; 6241da177e4SLinus Torvalds } 6251da177e4SLinus Torvalds 6266d1029b5SAkinobu Mita /** 6276a727b43SJiri Slaby * simple_write_to_buffer - copy data from user space to the buffer 6286a727b43SJiri Slaby * @to: the buffer to write to 6296a727b43SJiri Slaby * @available: the size of the buffer 6306a727b43SJiri Slaby * @ppos: the current position in the buffer 6316a727b43SJiri Slaby * @from: the user space buffer to read from 6326a727b43SJiri Slaby * @count: the maximum number of bytes to read 6336a727b43SJiri Slaby * 6346a727b43SJiri Slaby * The simple_write_to_buffer() function reads up to @count bytes from the user 6356a727b43SJiri Slaby * space address starting at @from into the buffer @to at offset @ppos. 6366a727b43SJiri Slaby * 6376a727b43SJiri Slaby * On success, the number of bytes written is returned and the offset @ppos is 6386a727b43SJiri Slaby * advanced by this number, or negative value is returned on error. 6396a727b43SJiri Slaby **/ 6406a727b43SJiri Slaby ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, 6416a727b43SJiri Slaby const void __user *from, size_t count) 6426a727b43SJiri Slaby { 6436a727b43SJiri Slaby loff_t pos = *ppos; 6446a727b43SJiri Slaby size_t res; 6456a727b43SJiri Slaby 6466a727b43SJiri Slaby if (pos < 0) 6476a727b43SJiri Slaby return -EINVAL; 6486a727b43SJiri Slaby if (pos >= available || !count) 6496a727b43SJiri Slaby return 0; 6506a727b43SJiri Slaby if (count > available - pos) 6516a727b43SJiri Slaby count = available - pos; 6526a727b43SJiri Slaby res = copy_from_user(to + pos, from, count); 6536a727b43SJiri Slaby if (res == count) 6546a727b43SJiri Slaby return -EFAULT; 6556a727b43SJiri Slaby count -= res; 6566a727b43SJiri Slaby *ppos = pos + count; 6576a727b43SJiri Slaby return count; 6586a727b43SJiri Slaby } 6596a727b43SJiri Slaby 6606a727b43SJiri Slaby /** 6616d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 6626d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 6636d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 6646d1029b5SAkinobu Mita * @ppos: the current position in the buffer 6656d1029b5SAkinobu Mita * @from: the buffer to read from 6666d1029b5SAkinobu Mita * @available: the size of the buffer 6676d1029b5SAkinobu Mita * 6686d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 6696d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 6706d1029b5SAkinobu Mita * 6716d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6726d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6736d1029b5SAkinobu Mita **/ 67493b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 67593b07113SAkinobu Mita const void *from, size_t available) 67693b07113SAkinobu Mita { 67793b07113SAkinobu Mita loff_t pos = *ppos; 67893b07113SAkinobu Mita 67993b07113SAkinobu Mita if (pos < 0) 68093b07113SAkinobu Mita return -EINVAL; 68193b07113SAkinobu Mita if (pos >= available) 68293b07113SAkinobu Mita return 0; 68393b07113SAkinobu Mita if (count > available - pos) 68493b07113SAkinobu Mita count = available - pos; 68593b07113SAkinobu Mita memcpy(to, from + pos, count); 68693b07113SAkinobu Mita *ppos = pos + count; 68793b07113SAkinobu Mita 68893b07113SAkinobu Mita return count; 68993b07113SAkinobu Mita } 69093b07113SAkinobu Mita 6911da177e4SLinus Torvalds /* 6921da177e4SLinus Torvalds * Transaction based IO. 6931da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 6941da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 6951da177e4SLinus Torvalds * file-local buffer. 6961da177e4SLinus Torvalds */ 69776791ab2SIngo Molnar 69876791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 69976791ab2SIngo Molnar { 70076791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 70176791ab2SIngo Molnar 70276791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 70376791ab2SIngo Molnar 70476791ab2SIngo Molnar /* 70576791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 70676791ab2SIngo Molnar * ar->data is ready for reading. 70776791ab2SIngo Molnar */ 70876791ab2SIngo Molnar smp_mb(); 70976791ab2SIngo Molnar ar->size = n; 71076791ab2SIngo Molnar } 71176791ab2SIngo Molnar 7121da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 7131da177e4SLinus Torvalds { 7141da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 7151da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 7161da177e4SLinus Torvalds 7171da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 7181da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 7191da177e4SLinus Torvalds 7201da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 7211da177e4SLinus Torvalds if (!ar) 7221da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 7251da177e4SLinus Torvalds 7261da177e4SLinus Torvalds /* only one write allowed per open */ 7271da177e4SLinus Torvalds if (file->private_data) { 7281da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7291da177e4SLinus Torvalds free_page((unsigned long)ar); 7301da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 7311da177e4SLinus Torvalds } 7321da177e4SLinus Torvalds 7331da177e4SLinus Torvalds file->private_data = ar; 7341da177e4SLinus Torvalds 7351da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7361da177e4SLinus Torvalds 7371da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 7381da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 7391da177e4SLinus Torvalds 7401da177e4SLinus Torvalds return ar->data; 7411da177e4SLinus Torvalds } 7421da177e4SLinus Torvalds 7431da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 7441da177e4SLinus Torvalds { 7451da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 7461da177e4SLinus Torvalds 7471da177e4SLinus Torvalds if (!ar) 7481da177e4SLinus Torvalds return 0; 7491da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 7501da177e4SLinus Torvalds } 7511da177e4SLinus Torvalds 7521da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 7531da177e4SLinus Torvalds { 7541da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 7551da177e4SLinus Torvalds return 0; 7561da177e4SLinus Torvalds } 7571da177e4SLinus Torvalds 758acaefc25SArnd Bergmann /* Simple attribute files */ 759acaefc25SArnd Bergmann 760acaefc25SArnd Bergmann struct simple_attr { 7618b88b099SChristoph Hellwig int (*get)(void *, u64 *); 7628b88b099SChristoph Hellwig int (*set)(void *, u64); 763acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 764acaefc25SArnd Bergmann char set_buf[24]; 765acaefc25SArnd Bergmann void *data; 766acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 7677cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 768acaefc25SArnd Bergmann }; 769acaefc25SArnd Bergmann 770acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 771acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 772acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 7738b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 774acaefc25SArnd Bergmann const char *fmt) 775acaefc25SArnd Bergmann { 776acaefc25SArnd Bergmann struct simple_attr *attr; 777acaefc25SArnd Bergmann 778acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 779acaefc25SArnd Bergmann if (!attr) 780acaefc25SArnd Bergmann return -ENOMEM; 781acaefc25SArnd Bergmann 782acaefc25SArnd Bergmann attr->get = get; 783acaefc25SArnd Bergmann attr->set = set; 7848e18e294STheodore Ts'o attr->data = inode->i_private; 785acaefc25SArnd Bergmann attr->fmt = fmt; 7867cf34c76SIngo Molnar mutex_init(&attr->mutex); 787acaefc25SArnd Bergmann 788acaefc25SArnd Bergmann file->private_data = attr; 789acaefc25SArnd Bergmann 790acaefc25SArnd Bergmann return nonseekable_open(inode, file); 791acaefc25SArnd Bergmann } 792acaefc25SArnd Bergmann 79374bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 794acaefc25SArnd Bergmann { 795acaefc25SArnd Bergmann kfree(file->private_data); 796acaefc25SArnd Bergmann return 0; 797acaefc25SArnd Bergmann } 798acaefc25SArnd Bergmann 799acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 800acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 801acaefc25SArnd Bergmann size_t len, loff_t *ppos) 802acaefc25SArnd Bergmann { 803acaefc25SArnd Bergmann struct simple_attr *attr; 804acaefc25SArnd Bergmann size_t size; 805acaefc25SArnd Bergmann ssize_t ret; 806acaefc25SArnd Bergmann 807acaefc25SArnd Bergmann attr = file->private_data; 808acaefc25SArnd Bergmann 809acaefc25SArnd Bergmann if (!attr->get) 810acaefc25SArnd Bergmann return -EACCES; 811acaefc25SArnd Bergmann 8129261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8139261303aSChristoph Hellwig if (ret) 8149261303aSChristoph Hellwig return ret; 8159261303aSChristoph Hellwig 8168b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 817acaefc25SArnd Bergmann size = strlen(attr->get_buf); 8188b88b099SChristoph Hellwig } else { /* first read */ 8198b88b099SChristoph Hellwig u64 val; 8208b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 8218b88b099SChristoph Hellwig if (ret) 8228b88b099SChristoph Hellwig goto out; 8238b88b099SChristoph Hellwig 824acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 8258b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 8268b88b099SChristoph Hellwig } 827acaefc25SArnd Bergmann 828acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 8298b88b099SChristoph Hellwig out: 8307cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 831acaefc25SArnd Bergmann return ret; 832acaefc25SArnd Bergmann } 833acaefc25SArnd Bergmann 834acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 835acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 836acaefc25SArnd Bergmann size_t len, loff_t *ppos) 837acaefc25SArnd Bergmann { 838acaefc25SArnd Bergmann struct simple_attr *attr; 839acaefc25SArnd Bergmann u64 val; 840acaefc25SArnd Bergmann size_t size; 841acaefc25SArnd Bergmann ssize_t ret; 842acaefc25SArnd Bergmann 843acaefc25SArnd Bergmann attr = file->private_data; 844acaefc25SArnd Bergmann if (!attr->set) 845acaefc25SArnd Bergmann return -EACCES; 846acaefc25SArnd Bergmann 8479261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8489261303aSChristoph Hellwig if (ret) 8499261303aSChristoph Hellwig return ret; 8509261303aSChristoph Hellwig 851acaefc25SArnd Bergmann ret = -EFAULT; 852acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 853acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 854acaefc25SArnd Bergmann goto out; 855acaefc25SArnd Bergmann 856acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 857acaefc25SArnd Bergmann val = simple_strtol(attr->set_buf, NULL, 0); 85805cc0ceeSWu Fengguang ret = attr->set(attr->data, val); 85905cc0ceeSWu Fengguang if (ret == 0) 86005cc0ceeSWu Fengguang ret = len; /* on success, claim we got the whole input */ 861acaefc25SArnd Bergmann out: 8627cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 863acaefc25SArnd Bergmann return ret; 864acaefc25SArnd Bergmann } 865acaefc25SArnd Bergmann 8662596110aSChristoph Hellwig /** 8672596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 8682596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8692596110aSChristoph Hellwig * @fid: file handle to convert 8702596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8712596110aSChristoph Hellwig * @fh_type: type of file handle 8722596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8732596110aSChristoph Hellwig * 8742596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8752596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8762596110aSChristoph Hellwig * inode for the object specified in the file handle. 8772596110aSChristoph Hellwig */ 8782596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 8792596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8802596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8812596110aSChristoph Hellwig { 8822596110aSChristoph Hellwig struct inode *inode = NULL; 8832596110aSChristoph Hellwig 8842596110aSChristoph Hellwig if (fh_len < 2) 8852596110aSChristoph Hellwig return NULL; 8862596110aSChristoph Hellwig 8872596110aSChristoph Hellwig switch (fh_type) { 8882596110aSChristoph Hellwig case FILEID_INO32_GEN: 8892596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8902596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 8912596110aSChristoph Hellwig break; 8922596110aSChristoph Hellwig } 8932596110aSChristoph Hellwig 8944ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8952596110aSChristoph Hellwig } 8962596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 8972596110aSChristoph Hellwig 8982596110aSChristoph Hellwig /** 8992596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_parent export operation 9002596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 9012596110aSChristoph Hellwig * @fid: file handle to convert 9022596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 9032596110aSChristoph Hellwig * @fh_type: type of file handle 9042596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 9052596110aSChristoph Hellwig * 9062596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 9072596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 9082596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 9092596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 9102596110aSChristoph Hellwig */ 9112596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 9122596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 9132596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 9142596110aSChristoph Hellwig { 9152596110aSChristoph Hellwig struct inode *inode = NULL; 9162596110aSChristoph Hellwig 9172596110aSChristoph Hellwig if (fh_len <= 2) 9182596110aSChristoph Hellwig return NULL; 9192596110aSChristoph Hellwig 9202596110aSChristoph Hellwig switch (fh_type) { 9212596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 9222596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 9232596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 9242596110aSChristoph Hellwig break; 9252596110aSChristoph Hellwig } 9262596110aSChristoph Hellwig 9274ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 9282596110aSChristoph Hellwig } 9292596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 9302596110aSChristoph Hellwig 9311b061d92SChristoph Hellwig /** 9321b061d92SChristoph Hellwig * generic_file_fsync - generic fsync implementation for simple filesystems 9331b061d92SChristoph Hellwig * @file: file to synchronize 9341b061d92SChristoph Hellwig * @datasync: only synchronize essential metadata if true 9351b061d92SChristoph Hellwig * 9361b061d92SChristoph Hellwig * This is a generic implementation of the fsync method for simple 9371b061d92SChristoph Hellwig * filesystems which track all non-inode metadata in the buffers list 9381b061d92SChristoph Hellwig * hanging off the address_space structure. 9391b061d92SChristoph Hellwig */ 9401b061d92SChristoph Hellwig int generic_file_fsync(struct file *file, int datasync) 941d5aacad5SAl Viro { 942d5aacad5SAl Viro struct writeback_control wbc = { 943d5aacad5SAl Viro .sync_mode = WB_SYNC_ALL, 944d5aacad5SAl Viro .nr_to_write = 0, /* metadata-only; caller takes care of data */ 945d5aacad5SAl Viro }; 9467ea80859SChristoph Hellwig struct inode *inode = file->f_mapping->host; 947d5aacad5SAl Viro int err; 948d5aacad5SAl Viro int ret; 949d5aacad5SAl Viro 950d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 951d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 952d5aacad5SAl Viro return ret; 953d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 954d5aacad5SAl Viro return ret; 955d5aacad5SAl Viro 956d5aacad5SAl Viro err = sync_inode(inode, &wbc); 957d5aacad5SAl Viro if (ret == 0) 958d5aacad5SAl Viro ret = err; 959d5aacad5SAl Viro return ret; 960d5aacad5SAl Viro } 9611b061d92SChristoph Hellwig EXPORT_SYMBOL(generic_file_fsync); 9621b061d92SChristoph Hellwig 9631b061d92SChristoph Hellwig /* 9641b061d92SChristoph Hellwig * No-op implementation of ->fsync for in-memory filesystems. 9651b061d92SChristoph Hellwig */ 9661b061d92SChristoph Hellwig int noop_fsync(struct file *file, int datasync) 9671b061d92SChristoph Hellwig { 9681b061d92SChristoph Hellwig return 0; 9691b061d92SChristoph Hellwig } 970d5aacad5SAl Viro 9711da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_close); 9721da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_lseek); 9731da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_dir_open); 9741da177e4SLinus Torvalds EXPORT_SYMBOL(dcache_readdir); 9751da177e4SLinus Torvalds EXPORT_SYMBOL(generic_read_dir); 9761da177e4SLinus Torvalds EXPORT_SYMBOL(get_sb_pseudo); 977afddba49SNick Piggin EXPORT_SYMBOL(simple_write_begin); 978afddba49SNick Piggin EXPORT_SYMBOL(simple_write_end); 9791da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_inode_operations); 9801da177e4SLinus Torvalds EXPORT_SYMBOL(simple_dir_operations); 9811da177e4SLinus Torvalds EXPORT_SYMBOL(simple_empty); 9821da177e4SLinus Torvalds EXPORT_SYMBOL(simple_fill_super); 9831da177e4SLinus Torvalds EXPORT_SYMBOL(simple_getattr); 9841da177e4SLinus Torvalds EXPORT_SYMBOL(simple_link); 9851da177e4SLinus Torvalds EXPORT_SYMBOL(simple_lookup); 9861da177e4SLinus Torvalds EXPORT_SYMBOL(simple_pin_fs); 9871da177e4SLinus Torvalds EXPORT_SYMBOL(simple_readpage); 9881da177e4SLinus Torvalds EXPORT_SYMBOL(simple_release_fs); 9891da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rename); 9901da177e4SLinus Torvalds EXPORT_SYMBOL(simple_rmdir); 9911da177e4SLinus Torvalds EXPORT_SYMBOL(simple_statfs); 9921b061d92SChristoph Hellwig EXPORT_SYMBOL(noop_fsync); 9931da177e4SLinus Torvalds EXPORT_SYMBOL(simple_unlink); 9941da177e4SLinus Torvalds EXPORT_SYMBOL(simple_read_from_buffer); 9956a727b43SJiri Slaby EXPORT_SYMBOL(simple_write_to_buffer); 99693b07113SAkinobu Mita EXPORT_SYMBOL(memory_read_from_buffer); 99776791ab2SIngo Molnar EXPORT_SYMBOL(simple_transaction_set); 9981da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_get); 9991da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_read); 10001da177e4SLinus Torvalds EXPORT_SYMBOL(simple_transaction_release); 1001acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_open); 100274bedc4dSChristoph Hellwig EXPORT_SYMBOL_GPL(simple_attr_release); 1003acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_read); 1004acaefc25SArnd Bergmann EXPORT_SYMBOL_GPL(simple_attr_write); 1005