11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * fs/libfs.c 31da177e4SLinus Torvalds * Library for filesystems writers. 41da177e4SLinus Torvalds */ 51da177e4SLinus Torvalds 6630d9c47SPaul Gortmaker #include <linux/export.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> 1387dc800bSAl Viro #include <linux/namei.h> 142596110aSChristoph Hellwig #include <linux/exportfs.h> 15d5aacad5SAl Viro #include <linux/writeback.h> 16ff01bb48SAl Viro #include <linux/buffer_head.h> /* sync_mapping_buffers */ 177cf34c76SIngo Molnar 181da177e4SLinus Torvalds #include <asm/uaccess.h> 191da177e4SLinus Torvalds 20a4464dbcSAl Viro #include "internal.h" 21a4464dbcSAl Viro 22da502956SNick Piggin static inline int simple_positive(struct dentry *dentry) 23da502956SNick Piggin { 24da502956SNick Piggin return dentry->d_inode && !d_unhashed(dentry); 25da502956SNick Piggin } 26da502956SNick Piggin 271da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 281da177e4SLinus Torvalds struct kstat *stat) 291da177e4SLinus Torvalds { 301da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 311da177e4SLinus Torvalds generic_fillattr(inode, stat); 321da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 331da177e4SLinus Torvalds return 0; 341da177e4SLinus Torvalds } 3512f38872SAl Viro EXPORT_SYMBOL(simple_getattr); 361da177e4SLinus Torvalds 37726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 381da177e4SLinus Torvalds { 39726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 401da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 411da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 421da177e4SLinus Torvalds return 0; 431da177e4SLinus Torvalds } 4412f38872SAl Viro EXPORT_SYMBOL(simple_statfs); 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds /* 471da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 481da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 491da177e4SLinus Torvalds */ 50fe15ce44SNick Piggin static int simple_delete_dentry(const struct dentry *dentry) 511da177e4SLinus Torvalds { 521da177e4SLinus Torvalds return 1; 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds /* 561da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 571da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 581da177e4SLinus Torvalds */ 5900cd8dd3SAl Viro struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) 601da177e4SLinus Torvalds { 613ba13d17SAl Viro static const struct dentry_operations simple_dentry_operations = { 621da177e4SLinus Torvalds .d_delete = simple_delete_dentry, 631da177e4SLinus Torvalds }; 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 661da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 6774931da7SAl Viro if (!dentry->d_sb->s_d_op) 68fb045adbSNick Piggin d_set_d_op(dentry, &simple_dentry_operations); 691da177e4SLinus Torvalds d_add(dentry, NULL); 701da177e4SLinus Torvalds return NULL; 711da177e4SLinus Torvalds } 7212f38872SAl Viro EXPORT_SYMBOL(simple_lookup); 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 751da177e4SLinus Torvalds { 7626fe5750SLinus Torvalds static struct qstr cursor_name = QSTR_INIT(".", 1); 771da177e4SLinus Torvalds 780f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 811da177e4SLinus Torvalds } 8212f38872SAl Viro EXPORT_SYMBOL(dcache_dir_open); 831da177e4SLinus Torvalds 841da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 851da177e4SLinus Torvalds { 861da177e4SLinus Torvalds dput(file->private_data); 871da177e4SLinus Torvalds return 0; 881da177e4SLinus Torvalds } 8912f38872SAl Viro EXPORT_SYMBOL(dcache_dir_close); 901da177e4SLinus Torvalds 91965c8e59SAndrew Morton loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) 921da177e4SLinus Torvalds { 932fd6b7f5SNick Piggin struct dentry *dentry = file->f_path.dentry; 942fd6b7f5SNick Piggin mutex_lock(&dentry->d_inode->i_mutex); 95965c8e59SAndrew Morton switch (whence) { 961da177e4SLinus Torvalds case 1: 971da177e4SLinus Torvalds offset += file->f_pos; 981da177e4SLinus Torvalds case 0: 991da177e4SLinus Torvalds if (offset >= 0) 1001da177e4SLinus Torvalds break; 1011da177e4SLinus Torvalds default: 1022fd6b7f5SNick Piggin mutex_unlock(&dentry->d_inode->i_mutex); 1031da177e4SLinus Torvalds return -EINVAL; 1041da177e4SLinus Torvalds } 1051da177e4SLinus Torvalds if (offset != file->f_pos) { 1061da177e4SLinus Torvalds file->f_pos = offset; 1071da177e4SLinus Torvalds if (file->f_pos >= 2) { 1081da177e4SLinus Torvalds struct list_head *p; 1091da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 1101da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 1111da177e4SLinus Torvalds 1122fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1132fd6b7f5SNick Piggin /* d_lock not required for cursor */ 1145160ee6fSEric Dumazet list_del(&cursor->d_u.d_child); 1152fd6b7f5SNick Piggin p = dentry->d_subdirs.next; 1162fd6b7f5SNick Piggin while (n && p != &dentry->d_subdirs) { 1171da177e4SLinus Torvalds struct dentry *next; 1185160ee6fSEric Dumazet next = list_entry(p, struct dentry, d_u.d_child); 1192fd6b7f5SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 120da502956SNick Piggin if (simple_positive(next)) 1211da177e4SLinus Torvalds n--; 122da502956SNick Piggin spin_unlock(&next->d_lock); 1231da177e4SLinus Torvalds p = p->next; 1241da177e4SLinus Torvalds } 1255160ee6fSEric Dumazet list_add_tail(&cursor->d_u.d_child, p); 1262fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1271da177e4SLinus Torvalds } 1281da177e4SLinus Torvalds } 1292fd6b7f5SNick Piggin mutex_unlock(&dentry->d_inode->i_mutex); 1301da177e4SLinus Torvalds return offset; 1311da177e4SLinus Torvalds } 13212f38872SAl Viro EXPORT_SYMBOL(dcache_dir_lseek); 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1351da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1361da177e4SLinus Torvalds { 1371da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds /* 1411da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1421da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1431da177e4SLinus Torvalds * both impossible due to the lock on directory. 1441da177e4SLinus Torvalds */ 1451da177e4SLinus Torvalds 1465f99f4e7SAl Viro int dcache_readdir(struct file *file, struct dir_context *ctx) 1471da177e4SLinus Torvalds { 1485f99f4e7SAl Viro struct dentry *dentry = file->f_path.dentry; 1495f99f4e7SAl Viro struct dentry *cursor = file->private_data; 1505160ee6fSEric Dumazet struct list_head *p, *q = &cursor->d_u.d_child; 1511da177e4SLinus Torvalds 1525f99f4e7SAl Viro if (!dir_emit_dots(file, ctx)) 1535f99f4e7SAl Viro return 0; 1542fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1555f99f4e7SAl Viro if (ctx->pos == 2) 1561bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1571bfba4e8SAkinobu Mita 1581da177e4SLinus Torvalds for (p = q->next; p != &dentry->d_subdirs; p = p->next) { 1595f99f4e7SAl Viro struct dentry *next = list_entry(p, struct dentry, d_u.d_child); 160da502956SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 161da502956SNick Piggin if (!simple_positive(next)) { 162da502956SNick Piggin spin_unlock(&next->d_lock); 1631da177e4SLinus Torvalds continue; 164da502956SNick Piggin } 1651da177e4SLinus Torvalds 166da502956SNick Piggin spin_unlock(&next->d_lock); 1672fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1685f99f4e7SAl Viro if (!dir_emit(ctx, next->d_name.name, next->d_name.len, 1695f99f4e7SAl Viro next->d_inode->i_ino, dt_type(next->d_inode))) 1701da177e4SLinus Torvalds return 0; 1712fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1722fd6b7f5SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 1731da177e4SLinus Torvalds /* next is still alive */ 1741bfba4e8SAkinobu Mita list_move(q, p); 1752fd6b7f5SNick Piggin spin_unlock(&next->d_lock); 1761da177e4SLinus Torvalds p = q; 1775f99f4e7SAl Viro ctx->pos++; 1781da177e4SLinus Torvalds } 1792fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1801da177e4SLinus Torvalds return 0; 1811da177e4SLinus Torvalds } 18212f38872SAl Viro EXPORT_SYMBOL(dcache_readdir); 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1851da177e4SLinus Torvalds { 1861da177e4SLinus Torvalds return -EISDIR; 1871da177e4SLinus Torvalds } 18812f38872SAl Viro EXPORT_SYMBOL(generic_read_dir); 1891da177e4SLinus Torvalds 1904b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1911da177e4SLinus Torvalds .open = dcache_dir_open, 1921da177e4SLinus Torvalds .release = dcache_dir_close, 1931da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1941da177e4SLinus Torvalds .read = generic_read_dir, 1955f99f4e7SAl Viro .iterate = dcache_readdir, 1961b061d92SChristoph Hellwig .fsync = noop_fsync, 1971da177e4SLinus Torvalds }; 19812f38872SAl Viro EXPORT_SYMBOL(simple_dir_operations); 1991da177e4SLinus Torvalds 20092e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 2011da177e4SLinus Torvalds .lookup = simple_lookup, 2021da177e4SLinus Torvalds }; 20312f38872SAl Viro EXPORT_SYMBOL(simple_dir_inode_operations); 2041da177e4SLinus Torvalds 205759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 206759b9775SHugh Dickins .statfs = simple_statfs, 207759b9775SHugh Dickins }; 208759b9775SHugh Dickins 2091da177e4SLinus Torvalds /* 2101da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 2111da177e4SLinus Torvalds * will never be mountable) 2121da177e4SLinus Torvalds */ 21351139adaSAl Viro struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, 214c74a1cbbSAl Viro const struct super_operations *ops, 215c74a1cbbSAl Viro const struct dentry_operations *dops, unsigned long magic) 2161da177e4SLinus Torvalds { 2179249e17fSDavid Howells struct super_block *s; 2181da177e4SLinus Torvalds struct dentry *dentry; 2191da177e4SLinus Torvalds struct inode *root; 22026fe5750SLinus Torvalds struct qstr d_name = QSTR_INIT(name, strlen(name)); 2211da177e4SLinus Torvalds 2229249e17fSDavid Howells s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); 2231da177e4SLinus Torvalds if (IS_ERR(s)) 22451139adaSAl Viro return ERR_CAST(s); 2251da177e4SLinus Torvalds 22689a4eb4bSJeff Layton s->s_maxbytes = MAX_LFS_FILESIZE; 2273971e1a9SAlex Nixon s->s_blocksize = PAGE_SIZE; 2283971e1a9SAlex Nixon s->s_blocksize_bits = PAGE_SHIFT; 2291da177e4SLinus Torvalds s->s_magic = magic; 230759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2311da177e4SLinus Torvalds s->s_time_gran = 1; 2321da177e4SLinus Torvalds root = new_inode(s); 2331da177e4SLinus Torvalds if (!root) 2341da177e4SLinus Torvalds goto Enomem; 2351a1c9bb4SJeff Layton /* 2361a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2371a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2381a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2391a1c9bb4SJeff Layton */ 2401a1c9bb4SJeff Layton root->i_ino = 1; 2411da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2421da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 243a4464dbcSAl Viro dentry = __d_alloc(s, &d_name); 2441da177e4SLinus Torvalds if (!dentry) { 2451da177e4SLinus Torvalds iput(root); 2461da177e4SLinus Torvalds goto Enomem; 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds d_instantiate(dentry, root); 2491da177e4SLinus Torvalds s->s_root = dentry; 250c74a1cbbSAl Viro s->s_d_op = dops; 2511da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 25251139adaSAl Viro return dget(s->s_root); 2531da177e4SLinus Torvalds 2541da177e4SLinus Torvalds Enomem: 2556f5bbff9SAl Viro deactivate_locked_super(s); 25651139adaSAl Viro return ERR_PTR(-ENOMEM); 2571da177e4SLinus Torvalds } 25812f38872SAl Viro EXPORT_SYMBOL(mount_pseudo); 2591da177e4SLinus Torvalds 26020955e89SStephen Boyd int simple_open(struct inode *inode, struct file *file) 26120955e89SStephen Boyd { 26220955e89SStephen Boyd if (inode->i_private) 26320955e89SStephen Boyd file->private_data = inode->i_private; 26420955e89SStephen Boyd return 0; 26520955e89SStephen Boyd } 26612f38872SAl Viro EXPORT_SYMBOL(simple_open); 26720955e89SStephen Boyd 2681da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2691da177e4SLinus Torvalds { 2701da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2711da177e4SLinus Torvalds 2721da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 273d8c76e6fSDave Hansen inc_nlink(inode); 2747de9c6eeSAl Viro ihold(inode); 2751da177e4SLinus Torvalds dget(dentry); 2761da177e4SLinus Torvalds d_instantiate(dentry, inode); 2771da177e4SLinus Torvalds return 0; 2781da177e4SLinus Torvalds } 27912f38872SAl Viro EXPORT_SYMBOL(simple_link); 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2821da177e4SLinus Torvalds { 2831da177e4SLinus Torvalds struct dentry *child; 2841da177e4SLinus Torvalds int ret = 0; 2851da177e4SLinus Torvalds 2862fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 287da502956SNick Piggin list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { 288da502956SNick Piggin spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); 289da502956SNick Piggin if (simple_positive(child)) { 290da502956SNick Piggin spin_unlock(&child->d_lock); 2911da177e4SLinus Torvalds goto out; 292da502956SNick Piggin } 293da502956SNick Piggin spin_unlock(&child->d_lock); 294da502956SNick Piggin } 2951da177e4SLinus Torvalds ret = 1; 2961da177e4SLinus Torvalds out: 2972fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 2981da177e4SLinus Torvalds return ret; 2991da177e4SLinus Torvalds } 30012f38872SAl Viro EXPORT_SYMBOL(simple_empty); 3011da177e4SLinus Torvalds 3021da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 3031da177e4SLinus Torvalds { 3041da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 3051da177e4SLinus Torvalds 3061da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 3079a53c3a7SDave Hansen drop_nlink(inode); 3081da177e4SLinus Torvalds dput(dentry); 3091da177e4SLinus Torvalds return 0; 3101da177e4SLinus Torvalds } 31112f38872SAl Viro EXPORT_SYMBOL(simple_unlink); 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 3141da177e4SLinus Torvalds { 3151da177e4SLinus Torvalds if (!simple_empty(dentry)) 3161da177e4SLinus Torvalds return -ENOTEMPTY; 3171da177e4SLinus Torvalds 3189a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 3191da177e4SLinus Torvalds simple_unlink(dir, dentry); 3209a53c3a7SDave Hansen drop_nlink(dir); 3211da177e4SLinus Torvalds return 0; 3221da177e4SLinus Torvalds } 32312f38872SAl Viro EXPORT_SYMBOL(simple_rmdir); 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3261da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3271da177e4SLinus Torvalds { 3281da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3291da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3301da177e4SLinus Torvalds 3311da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3321da177e4SLinus Torvalds return -ENOTEMPTY; 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds if (new_dentry->d_inode) { 3351da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 336841590ceSAl Viro if (they_are_dirs) { 337841590ceSAl Viro drop_nlink(new_dentry->d_inode); 3389a53c3a7SDave Hansen drop_nlink(old_dir); 339841590ceSAl Viro } 3401da177e4SLinus Torvalds } else if (they_are_dirs) { 3419a53c3a7SDave Hansen drop_nlink(old_dir); 342d8c76e6fSDave Hansen inc_nlink(new_dir); 3431da177e4SLinus Torvalds } 3441da177e4SLinus Torvalds 3451da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3461da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds return 0; 3491da177e4SLinus Torvalds } 35012f38872SAl Viro EXPORT_SYMBOL(simple_rename); 3511da177e4SLinus Torvalds 3527bb46a67Snpiggin@suse.de /** 353eef2380cSChristoph Hellwig * simple_setattr - setattr for simple filesystem 3547bb46a67Snpiggin@suse.de * @dentry: dentry 3557bb46a67Snpiggin@suse.de * @iattr: iattr structure 3567bb46a67Snpiggin@suse.de * 3577bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3587bb46a67Snpiggin@suse.de * 359eef2380cSChristoph Hellwig * simple_setattr is a simple ->setattr implementation without a proper 360eef2380cSChristoph Hellwig * implementation of size changes. 361eef2380cSChristoph Hellwig * 362eef2380cSChristoph Hellwig * It can either be used for in-memory filesystems or special files 363eef2380cSChristoph Hellwig * on simple regular filesystems. Anything that needs to change on-disk 364eef2380cSChristoph Hellwig * or wire state on size changes needs its own setattr method. 3657bb46a67Snpiggin@suse.de */ 3667bb46a67Snpiggin@suse.de int simple_setattr(struct dentry *dentry, struct iattr *iattr) 3677bb46a67Snpiggin@suse.de { 3687bb46a67Snpiggin@suse.de struct inode *inode = dentry->d_inode; 3697bb46a67Snpiggin@suse.de int error; 3707bb46a67Snpiggin@suse.de 3717bb46a67Snpiggin@suse.de error = inode_change_ok(inode, iattr); 3727bb46a67Snpiggin@suse.de if (error) 3737bb46a67Snpiggin@suse.de return error; 3747bb46a67Snpiggin@suse.de 3752c27c65eSChristoph Hellwig if (iattr->ia_valid & ATTR_SIZE) 3762c27c65eSChristoph Hellwig truncate_setsize(inode, iattr->ia_size); 3776a1a90adSChristoph Hellwig setattr_copy(inode, iattr); 378eef2380cSChristoph Hellwig mark_inode_dirty(inode); 379eef2380cSChristoph Hellwig return 0; 3807bb46a67Snpiggin@suse.de } 3817bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setattr); 3827bb46a67Snpiggin@suse.de 3831da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3841da177e4SLinus Torvalds { 385c0d92cbcSPekka J Enberg clear_highpage(page); 3861da177e4SLinus Torvalds flush_dcache_page(page); 3871da177e4SLinus Torvalds SetPageUptodate(page); 3881da177e4SLinus Torvalds unlock_page(page); 3891da177e4SLinus Torvalds return 0; 3901da177e4SLinus Torvalds } 39112f38872SAl Viro EXPORT_SYMBOL(simple_readpage); 3921da177e4SLinus Torvalds 393afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 394afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 395afddba49SNick Piggin struct page **pagep, void **fsdata) 396afddba49SNick Piggin { 397afddba49SNick Piggin struct page *page; 398afddba49SNick Piggin pgoff_t index; 399afddba49SNick Piggin 400afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 401afddba49SNick Piggin 40254566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 403afddba49SNick Piggin if (!page) 404afddba49SNick Piggin return -ENOMEM; 405afddba49SNick Piggin 406afddba49SNick Piggin *pagep = page; 407afddba49SNick Piggin 408193cf4b9SBoaz Harrosh if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { 409193cf4b9SBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 410193cf4b9SBoaz Harrosh 411193cf4b9SBoaz Harrosh zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); 412193cf4b9SBoaz Harrosh } 413193cf4b9SBoaz Harrosh return 0; 414afddba49SNick Piggin } 41512f38872SAl Viro EXPORT_SYMBOL(simple_write_begin); 416afddba49SNick Piggin 417ad2a722fSBoaz Harrosh /** 418ad2a722fSBoaz Harrosh * simple_write_end - .write_end helper for non-block-device FSes 419ad2a722fSBoaz Harrosh * @available: See .write_end of address_space_operations 420ad2a722fSBoaz Harrosh * @file: " 421ad2a722fSBoaz Harrosh * @mapping: " 422ad2a722fSBoaz Harrosh * @pos: " 423ad2a722fSBoaz Harrosh * @len: " 424ad2a722fSBoaz Harrosh * @copied: " 425ad2a722fSBoaz Harrosh * @page: " 426ad2a722fSBoaz Harrosh * @fsdata: " 427ad2a722fSBoaz Harrosh * 428ad2a722fSBoaz Harrosh * simple_write_end does the minimum needed for updating a page after writing is 429ad2a722fSBoaz Harrosh * done. It has the same API signature as the .write_end of 430ad2a722fSBoaz Harrosh * address_space_operations vector. So it can just be set onto .write_end for 431ad2a722fSBoaz Harrosh * FSes that don't need any other processing. i_mutex is assumed to be held. 432ad2a722fSBoaz Harrosh * Block based filesystems should use generic_write_end(). 433ad2a722fSBoaz Harrosh * NOTE: Even though i_size might get updated by this function, mark_inode_dirty 434ad2a722fSBoaz Harrosh * is not called, so a filesystem that actually does store data in .write_inode 435ad2a722fSBoaz Harrosh * should extend on what's done here with a call to mark_inode_dirty() in the 436ad2a722fSBoaz Harrosh * case that i_size has changed. 437ad2a722fSBoaz Harrosh */ 438ad2a722fSBoaz Harrosh int simple_write_end(struct file *file, struct address_space *mapping, 439ad2a722fSBoaz Harrosh loff_t pos, unsigned len, unsigned copied, 440ad2a722fSBoaz Harrosh struct page *page, void *fsdata) 4411da177e4SLinus Torvalds { 4421da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 443ad2a722fSBoaz Harrosh loff_t last_pos = pos + copied; 444ad2a722fSBoaz Harrosh 445ad2a722fSBoaz Harrosh /* zero the stale part of the page if we did a short copy */ 446ad2a722fSBoaz Harrosh if (copied < len) { 447ad2a722fSBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 448ad2a722fSBoaz Harrosh 449ad2a722fSBoaz Harrosh zero_user(page, from + copied, len - copied); 450ad2a722fSBoaz Harrosh } 4511da177e4SLinus Torvalds 452955eff5aSNick Piggin if (!PageUptodate(page)) 453955eff5aSNick Piggin SetPageUptodate(page); 4541da177e4SLinus Torvalds /* 4551da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 4561b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 4571da177e4SLinus Torvalds */ 458ad2a722fSBoaz Harrosh if (last_pos > inode->i_size) 459ad2a722fSBoaz Harrosh i_size_write(inode, last_pos); 460ad2a722fSBoaz Harrosh 4611da177e4SLinus Torvalds set_page_dirty(page); 462afddba49SNick Piggin unlock_page(page); 463afddba49SNick Piggin page_cache_release(page); 464afddba49SNick Piggin 465afddba49SNick Piggin return copied; 466afddba49SNick Piggin } 46712f38872SAl Viro EXPORT_SYMBOL(simple_write_end); 468afddba49SNick Piggin 4691a1c9bb4SJeff Layton /* 4701a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4711a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4721a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4731a1c9bb4SJeff Layton */ 4747d683a09SRoberto Sassu int simple_fill_super(struct super_block *s, unsigned long magic, 4757d683a09SRoberto Sassu struct tree_descr *files) 4761da177e4SLinus Torvalds { 4771da177e4SLinus Torvalds struct inode *inode; 4781da177e4SLinus Torvalds struct dentry *root; 4791da177e4SLinus Torvalds struct dentry *dentry; 4801da177e4SLinus Torvalds int i; 4811da177e4SLinus Torvalds 4821da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 4831da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 4841da177e4SLinus Torvalds s->s_magic = magic; 485759b9775SHugh Dickins s->s_op = &simple_super_operations; 4861da177e4SLinus Torvalds s->s_time_gran = 1; 4871da177e4SLinus Torvalds 4881da177e4SLinus Torvalds inode = new_inode(s); 4891da177e4SLinus Torvalds if (!inode) 4901da177e4SLinus Torvalds return -ENOMEM; 4911a1c9bb4SJeff Layton /* 4921a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 4931a1c9bb4SJeff Layton * entry at index 1 4941a1c9bb4SJeff Layton */ 4951a1c9bb4SJeff Layton inode->i_ino = 1; 4961da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 4971da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 4981da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 4991da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 500bfe86848SMiklos Szeredi set_nlink(inode, 2); 50148fde701SAl Viro root = d_make_root(inode); 50248fde701SAl Viro if (!root) 5031da177e4SLinus Torvalds return -ENOMEM; 5041da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 5051da177e4SLinus Torvalds if (!files->name) 5061da177e4SLinus Torvalds continue; 5071a1c9bb4SJeff Layton 5081a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 5091a1c9bb4SJeff Layton if (unlikely(i == 1)) 5101a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 5111a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 5121a1c9bb4SJeff Layton s->s_type->name); 5131a1c9bb4SJeff Layton 5141da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 5151da177e4SLinus Torvalds if (!dentry) 5161da177e4SLinus Torvalds goto out; 5171da177e4SLinus Torvalds inode = new_inode(s); 51832096ea1SKonstantin Khlebnikov if (!inode) { 51932096ea1SKonstantin Khlebnikov dput(dentry); 5201da177e4SLinus Torvalds goto out; 52132096ea1SKonstantin Khlebnikov } 5221da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 5231da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5241da177e4SLinus Torvalds inode->i_fop = files->ops; 5251da177e4SLinus Torvalds inode->i_ino = i; 5261da177e4SLinus Torvalds d_add(dentry, inode); 5271da177e4SLinus Torvalds } 5281da177e4SLinus Torvalds s->s_root = root; 5291da177e4SLinus Torvalds return 0; 5301da177e4SLinus Torvalds out: 5311da177e4SLinus Torvalds d_genocide(root); 532640946f2SAl Viro shrink_dcache_parent(root); 5331da177e4SLinus Torvalds dput(root); 5341da177e4SLinus Torvalds return -ENOMEM; 5351da177e4SLinus Torvalds } 53612f38872SAl Viro EXPORT_SYMBOL(simple_fill_super); 5371da177e4SLinus Torvalds 5381da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 5391da177e4SLinus Torvalds 5401f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 5411da177e4SLinus Torvalds { 5421da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 5431da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5441da177e4SLinus Torvalds if (unlikely(!*mount)) { 5451da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5462452992aSAl Viro mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); 5471da177e4SLinus Torvalds if (IS_ERR(mnt)) 5481da177e4SLinus Torvalds return PTR_ERR(mnt); 5491da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5501da177e4SLinus Torvalds if (!*mount) 5511da177e4SLinus Torvalds *mount = mnt; 5521da177e4SLinus Torvalds } 5531da177e4SLinus Torvalds mntget(*mount); 5541da177e4SLinus Torvalds ++*count; 5551da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5561da177e4SLinus Torvalds mntput(mnt); 5571da177e4SLinus Torvalds return 0; 5581da177e4SLinus Torvalds } 55912f38872SAl Viro EXPORT_SYMBOL(simple_pin_fs); 5601da177e4SLinus Torvalds 5611da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5621da177e4SLinus Torvalds { 5631da177e4SLinus Torvalds struct vfsmount *mnt; 5641da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5651da177e4SLinus Torvalds mnt = *mount; 5661da177e4SLinus Torvalds if (!--*count) 5671da177e4SLinus Torvalds *mount = NULL; 5681da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5691da177e4SLinus Torvalds mntput(mnt); 5701da177e4SLinus Torvalds } 57112f38872SAl Viro EXPORT_SYMBOL(simple_release_fs); 5721da177e4SLinus Torvalds 5736d1029b5SAkinobu Mita /** 5746d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5756d1029b5SAkinobu Mita * @to: the user space buffer to read to 5766d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5776d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5786d1029b5SAkinobu Mita * @from: the buffer to read from 5796d1029b5SAkinobu Mita * @available: the size of the buffer 5806d1029b5SAkinobu Mita * 5816d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 5826d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 5836d1029b5SAkinobu Mita * 5846d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5856d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5866d1029b5SAkinobu Mita **/ 5871da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 5881da177e4SLinus Torvalds const void *from, size_t available) 5891da177e4SLinus Torvalds { 5901da177e4SLinus Torvalds loff_t pos = *ppos; 59114be2746SSteven Rostedt size_t ret; 59214be2746SSteven Rostedt 5931da177e4SLinus Torvalds if (pos < 0) 5941da177e4SLinus Torvalds return -EINVAL; 59514be2746SSteven Rostedt if (pos >= available || !count) 5961da177e4SLinus Torvalds return 0; 5971da177e4SLinus Torvalds if (count > available - pos) 5981da177e4SLinus Torvalds count = available - pos; 59914be2746SSteven Rostedt ret = copy_to_user(to, from + pos, count); 60014be2746SSteven Rostedt if (ret == count) 6011da177e4SLinus Torvalds return -EFAULT; 60214be2746SSteven Rostedt count -= ret; 6031da177e4SLinus Torvalds *ppos = pos + count; 6041da177e4SLinus Torvalds return count; 6051da177e4SLinus Torvalds } 60612f38872SAl Viro EXPORT_SYMBOL(simple_read_from_buffer); 6071da177e4SLinus Torvalds 6086d1029b5SAkinobu Mita /** 6096a727b43SJiri Slaby * simple_write_to_buffer - copy data from user space to the buffer 6106a727b43SJiri Slaby * @to: the buffer to write to 6116a727b43SJiri Slaby * @available: the size of the buffer 6126a727b43SJiri Slaby * @ppos: the current position in the buffer 6136a727b43SJiri Slaby * @from: the user space buffer to read from 6146a727b43SJiri Slaby * @count: the maximum number of bytes to read 6156a727b43SJiri Slaby * 6166a727b43SJiri Slaby * The simple_write_to_buffer() function reads up to @count bytes from the user 6176a727b43SJiri Slaby * space address starting at @from into the buffer @to at offset @ppos. 6186a727b43SJiri Slaby * 6196a727b43SJiri Slaby * On success, the number of bytes written is returned and the offset @ppos is 6206a727b43SJiri Slaby * advanced by this number, or negative value is returned on error. 6216a727b43SJiri Slaby **/ 6226a727b43SJiri Slaby ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, 6236a727b43SJiri Slaby const void __user *from, size_t count) 6246a727b43SJiri Slaby { 6256a727b43SJiri Slaby loff_t pos = *ppos; 6266a727b43SJiri Slaby size_t res; 6276a727b43SJiri Slaby 6286a727b43SJiri Slaby if (pos < 0) 6296a727b43SJiri Slaby return -EINVAL; 6306a727b43SJiri Slaby if (pos >= available || !count) 6316a727b43SJiri Slaby return 0; 6326a727b43SJiri Slaby if (count > available - pos) 6336a727b43SJiri Slaby count = available - pos; 6346a727b43SJiri Slaby res = copy_from_user(to + pos, from, count); 6356a727b43SJiri Slaby if (res == count) 6366a727b43SJiri Slaby return -EFAULT; 6376a727b43SJiri Slaby count -= res; 6386a727b43SJiri Slaby *ppos = pos + count; 6396a727b43SJiri Slaby return count; 6406a727b43SJiri Slaby } 64112f38872SAl Viro EXPORT_SYMBOL(simple_write_to_buffer); 6426a727b43SJiri Slaby 6436a727b43SJiri Slaby /** 6446d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 6456d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 6466d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 6476d1029b5SAkinobu Mita * @ppos: the current position in the buffer 6486d1029b5SAkinobu Mita * @from: the buffer to read from 6496d1029b5SAkinobu Mita * @available: the size of the buffer 6506d1029b5SAkinobu Mita * 6516d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 6526d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 6536d1029b5SAkinobu Mita * 6546d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6556d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6566d1029b5SAkinobu Mita **/ 65793b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 65893b07113SAkinobu Mita const void *from, size_t available) 65993b07113SAkinobu Mita { 66093b07113SAkinobu Mita loff_t pos = *ppos; 66193b07113SAkinobu Mita 66293b07113SAkinobu Mita if (pos < 0) 66393b07113SAkinobu Mita return -EINVAL; 66493b07113SAkinobu Mita if (pos >= available) 66593b07113SAkinobu Mita return 0; 66693b07113SAkinobu Mita if (count > available - pos) 66793b07113SAkinobu Mita count = available - pos; 66893b07113SAkinobu Mita memcpy(to, from + pos, count); 66993b07113SAkinobu Mita *ppos = pos + count; 67093b07113SAkinobu Mita 67193b07113SAkinobu Mita return count; 67293b07113SAkinobu Mita } 67312f38872SAl Viro EXPORT_SYMBOL(memory_read_from_buffer); 67493b07113SAkinobu Mita 6751da177e4SLinus Torvalds /* 6761da177e4SLinus Torvalds * Transaction based IO. 6771da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 6781da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 6791da177e4SLinus Torvalds * file-local buffer. 6801da177e4SLinus Torvalds */ 68176791ab2SIngo Molnar 68276791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 68376791ab2SIngo Molnar { 68476791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 68576791ab2SIngo Molnar 68676791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 68776791ab2SIngo Molnar 68876791ab2SIngo Molnar /* 68976791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 69076791ab2SIngo Molnar * ar->data is ready for reading. 69176791ab2SIngo Molnar */ 69276791ab2SIngo Molnar smp_mb(); 69376791ab2SIngo Molnar ar->size = n; 69476791ab2SIngo Molnar } 69512f38872SAl Viro EXPORT_SYMBOL(simple_transaction_set); 69676791ab2SIngo Molnar 6971da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 6981da177e4SLinus Torvalds { 6991da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 7001da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 7011da177e4SLinus Torvalds 7021da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 7031da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 7061da177e4SLinus Torvalds if (!ar) 7071da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 7081da177e4SLinus Torvalds 7091da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 7101da177e4SLinus Torvalds 7111da177e4SLinus Torvalds /* only one write allowed per open */ 7121da177e4SLinus Torvalds if (file->private_data) { 7131da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7141da177e4SLinus Torvalds free_page((unsigned long)ar); 7151da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 7161da177e4SLinus Torvalds } 7171da177e4SLinus Torvalds 7181da177e4SLinus Torvalds file->private_data = ar; 7191da177e4SLinus Torvalds 7201da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7211da177e4SLinus Torvalds 7221da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 7231da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 7241da177e4SLinus Torvalds 7251da177e4SLinus Torvalds return ar->data; 7261da177e4SLinus Torvalds } 72712f38872SAl Viro EXPORT_SYMBOL(simple_transaction_get); 7281da177e4SLinus Torvalds 7291da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 7301da177e4SLinus Torvalds { 7311da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 7321da177e4SLinus Torvalds 7331da177e4SLinus Torvalds if (!ar) 7341da177e4SLinus Torvalds return 0; 7351da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 7361da177e4SLinus Torvalds } 73712f38872SAl Viro EXPORT_SYMBOL(simple_transaction_read); 7381da177e4SLinus Torvalds 7391da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 7401da177e4SLinus Torvalds { 7411da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 7421da177e4SLinus Torvalds return 0; 7431da177e4SLinus Torvalds } 74412f38872SAl Viro EXPORT_SYMBOL(simple_transaction_release); 7451da177e4SLinus Torvalds 746acaefc25SArnd Bergmann /* Simple attribute files */ 747acaefc25SArnd Bergmann 748acaefc25SArnd Bergmann struct simple_attr { 7498b88b099SChristoph Hellwig int (*get)(void *, u64 *); 7508b88b099SChristoph Hellwig int (*set)(void *, u64); 751acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 752acaefc25SArnd Bergmann char set_buf[24]; 753acaefc25SArnd Bergmann void *data; 754acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 7557cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 756acaefc25SArnd Bergmann }; 757acaefc25SArnd Bergmann 758acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 759acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 760acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 7618b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 762acaefc25SArnd Bergmann const char *fmt) 763acaefc25SArnd Bergmann { 764acaefc25SArnd Bergmann struct simple_attr *attr; 765acaefc25SArnd Bergmann 766acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 767acaefc25SArnd Bergmann if (!attr) 768acaefc25SArnd Bergmann return -ENOMEM; 769acaefc25SArnd Bergmann 770acaefc25SArnd Bergmann attr->get = get; 771acaefc25SArnd Bergmann attr->set = set; 7728e18e294STheodore Ts'o attr->data = inode->i_private; 773acaefc25SArnd Bergmann attr->fmt = fmt; 7747cf34c76SIngo Molnar mutex_init(&attr->mutex); 775acaefc25SArnd Bergmann 776acaefc25SArnd Bergmann file->private_data = attr; 777acaefc25SArnd Bergmann 778acaefc25SArnd Bergmann return nonseekable_open(inode, file); 779acaefc25SArnd Bergmann } 78012f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_open); 781acaefc25SArnd Bergmann 78274bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 783acaefc25SArnd Bergmann { 784acaefc25SArnd Bergmann kfree(file->private_data); 785acaefc25SArnd Bergmann return 0; 786acaefc25SArnd Bergmann } 78712f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ 788acaefc25SArnd Bergmann 789acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 790acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 791acaefc25SArnd Bergmann size_t len, loff_t *ppos) 792acaefc25SArnd Bergmann { 793acaefc25SArnd Bergmann struct simple_attr *attr; 794acaefc25SArnd Bergmann size_t size; 795acaefc25SArnd Bergmann ssize_t ret; 796acaefc25SArnd Bergmann 797acaefc25SArnd Bergmann attr = file->private_data; 798acaefc25SArnd Bergmann 799acaefc25SArnd Bergmann if (!attr->get) 800acaefc25SArnd Bergmann return -EACCES; 801acaefc25SArnd Bergmann 8029261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8039261303aSChristoph Hellwig if (ret) 8049261303aSChristoph Hellwig return ret; 8059261303aSChristoph Hellwig 8068b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 807acaefc25SArnd Bergmann size = strlen(attr->get_buf); 8088b88b099SChristoph Hellwig } else { /* first read */ 8098b88b099SChristoph Hellwig u64 val; 8108b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 8118b88b099SChristoph Hellwig if (ret) 8128b88b099SChristoph Hellwig goto out; 8138b88b099SChristoph Hellwig 814acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 8158b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 8168b88b099SChristoph Hellwig } 817acaefc25SArnd Bergmann 818acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 8198b88b099SChristoph Hellwig out: 8207cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 821acaefc25SArnd Bergmann return ret; 822acaefc25SArnd Bergmann } 82312f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_read); 824acaefc25SArnd Bergmann 825acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 826acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 827acaefc25SArnd Bergmann size_t len, loff_t *ppos) 828acaefc25SArnd Bergmann { 829acaefc25SArnd Bergmann struct simple_attr *attr; 830acaefc25SArnd Bergmann u64 val; 831acaefc25SArnd Bergmann size_t size; 832acaefc25SArnd Bergmann ssize_t ret; 833acaefc25SArnd Bergmann 834acaefc25SArnd Bergmann attr = file->private_data; 835acaefc25SArnd Bergmann if (!attr->set) 836acaefc25SArnd Bergmann return -EACCES; 837acaefc25SArnd Bergmann 8389261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8399261303aSChristoph Hellwig if (ret) 8409261303aSChristoph Hellwig return ret; 8419261303aSChristoph Hellwig 842acaefc25SArnd Bergmann ret = -EFAULT; 843acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 844acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 845acaefc25SArnd Bergmann goto out; 846acaefc25SArnd Bergmann 847acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 848f7b88631SAkinobu Mita val = simple_strtoll(attr->set_buf, NULL, 0); 84905cc0ceeSWu Fengguang ret = attr->set(attr->data, val); 85005cc0ceeSWu Fengguang if (ret == 0) 85105cc0ceeSWu Fengguang ret = len; /* on success, claim we got the whole input */ 852acaefc25SArnd Bergmann out: 8537cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 854acaefc25SArnd Bergmann return ret; 855acaefc25SArnd Bergmann } 85612f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_write); 857acaefc25SArnd Bergmann 8582596110aSChristoph Hellwig /** 8592596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 8602596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8612596110aSChristoph Hellwig * @fid: file handle to convert 8622596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8632596110aSChristoph Hellwig * @fh_type: type of file handle 8642596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8652596110aSChristoph Hellwig * 8662596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8672596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8682596110aSChristoph Hellwig * inode for the object specified in the file handle. 8692596110aSChristoph Hellwig */ 8702596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 8712596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8722596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8732596110aSChristoph Hellwig { 8742596110aSChristoph Hellwig struct inode *inode = NULL; 8752596110aSChristoph Hellwig 8762596110aSChristoph Hellwig if (fh_len < 2) 8772596110aSChristoph Hellwig return NULL; 8782596110aSChristoph Hellwig 8792596110aSChristoph Hellwig switch (fh_type) { 8802596110aSChristoph Hellwig case FILEID_INO32_GEN: 8812596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8822596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 8832596110aSChristoph Hellwig break; 8842596110aSChristoph Hellwig } 8852596110aSChristoph Hellwig 8864ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8872596110aSChristoph Hellwig } 8882596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 8892596110aSChristoph Hellwig 8902596110aSChristoph Hellwig /** 891ca186830SYanchuan Nian * generic_fh_to_parent - generic helper for the fh_to_parent export operation 8922596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8932596110aSChristoph Hellwig * @fid: file handle to convert 8942596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8952596110aSChristoph Hellwig * @fh_type: type of file handle 8962596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8972596110aSChristoph Hellwig * 8982596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8992596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 9002596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 9012596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 9022596110aSChristoph Hellwig */ 9032596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 9042596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 9052596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 9062596110aSChristoph Hellwig { 9072596110aSChristoph Hellwig struct inode *inode = NULL; 9082596110aSChristoph Hellwig 9092596110aSChristoph Hellwig if (fh_len <= 2) 9102596110aSChristoph Hellwig return NULL; 9112596110aSChristoph Hellwig 9122596110aSChristoph Hellwig switch (fh_type) { 9132596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 9142596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 9152596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 9162596110aSChristoph Hellwig break; 9172596110aSChristoph Hellwig } 9182596110aSChristoph Hellwig 9194ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 9202596110aSChristoph Hellwig } 9212596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 9222596110aSChristoph Hellwig 9231b061d92SChristoph Hellwig /** 9241b061d92SChristoph Hellwig * generic_file_fsync - generic fsync implementation for simple filesystems 9251b061d92SChristoph Hellwig * @file: file to synchronize 9261b061d92SChristoph Hellwig * @datasync: only synchronize essential metadata if true 9271b061d92SChristoph Hellwig * 9281b061d92SChristoph Hellwig * This is a generic implementation of the fsync method for simple 9291b061d92SChristoph Hellwig * filesystems which track all non-inode metadata in the buffers list 9301b061d92SChristoph Hellwig * hanging off the address_space structure. 9311b061d92SChristoph Hellwig */ 93202c24a82SJosef Bacik int generic_file_fsync(struct file *file, loff_t start, loff_t end, 93302c24a82SJosef Bacik int datasync) 934d5aacad5SAl Viro { 9357ea80859SChristoph Hellwig struct inode *inode = file->f_mapping->host; 936d5aacad5SAl Viro int err; 937d5aacad5SAl Viro int ret; 938d5aacad5SAl Viro 93902c24a82SJosef Bacik err = filemap_write_and_wait_range(inode->i_mapping, start, end); 94002c24a82SJosef Bacik if (err) 94102c24a82SJosef Bacik return err; 94202c24a82SJosef Bacik 94302c24a82SJosef Bacik mutex_lock(&inode->i_mutex); 944d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 945d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 94602c24a82SJosef Bacik goto out; 947d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 94802c24a82SJosef Bacik goto out; 949d5aacad5SAl Viro 950c3765016SChristoph Hellwig err = sync_inode_metadata(inode, 1); 951d5aacad5SAl Viro if (ret == 0) 952d5aacad5SAl Viro ret = err; 95302c24a82SJosef Bacik out: 95402c24a82SJosef Bacik mutex_unlock(&inode->i_mutex); 955d5aacad5SAl Viro return ret; 956d5aacad5SAl Viro } 9571b061d92SChristoph Hellwig EXPORT_SYMBOL(generic_file_fsync); 9581b061d92SChristoph Hellwig 95930ca22c7SPatrick J. LoPresti /** 96030ca22c7SPatrick J. LoPresti * generic_check_addressable - Check addressability of file system 96130ca22c7SPatrick J. LoPresti * @blocksize_bits: log of file system block size 96230ca22c7SPatrick J. LoPresti * @num_blocks: number of blocks in file system 96330ca22c7SPatrick J. LoPresti * 96430ca22c7SPatrick J. LoPresti * Determine whether a file system with @num_blocks blocks (and a 96530ca22c7SPatrick J. LoPresti * block size of 2**@blocksize_bits) is addressable by the sector_t 96630ca22c7SPatrick J. LoPresti * and page cache of the system. Return 0 if so and -EFBIG otherwise. 96730ca22c7SPatrick J. LoPresti */ 96830ca22c7SPatrick J. LoPresti int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) 96930ca22c7SPatrick J. LoPresti { 97030ca22c7SPatrick J. LoPresti u64 last_fs_block = num_blocks - 1; 971a33f13efSJoel Becker u64 last_fs_page = 972a33f13efSJoel Becker last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); 97330ca22c7SPatrick J. LoPresti 97430ca22c7SPatrick J. LoPresti if (unlikely(num_blocks == 0)) 97530ca22c7SPatrick J. LoPresti return 0; 97630ca22c7SPatrick J. LoPresti 97730ca22c7SPatrick J. LoPresti if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) 97830ca22c7SPatrick J. LoPresti return -EINVAL; 97930ca22c7SPatrick J. LoPresti 980a33f13efSJoel Becker if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || 981a33f13efSJoel Becker (last_fs_page > (pgoff_t)(~0ULL))) { 98230ca22c7SPatrick J. LoPresti return -EFBIG; 98330ca22c7SPatrick J. LoPresti } 98430ca22c7SPatrick J. LoPresti return 0; 98530ca22c7SPatrick J. LoPresti } 98630ca22c7SPatrick J. LoPresti EXPORT_SYMBOL(generic_check_addressable); 98730ca22c7SPatrick J. LoPresti 9881b061d92SChristoph Hellwig /* 9891b061d92SChristoph Hellwig * No-op implementation of ->fsync for in-memory filesystems. 9901b061d92SChristoph Hellwig */ 99102c24a82SJosef Bacik int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) 9921b061d92SChristoph Hellwig { 9931b061d92SChristoph Hellwig return 0; 9941b061d92SChristoph Hellwig } 9951b061d92SChristoph Hellwig EXPORT_SYMBOL(noop_fsync); 99687dc800bSAl Viro 99787dc800bSAl Viro void kfree_put_link(struct dentry *dentry, struct nameidata *nd, 99887dc800bSAl Viro void *cookie) 99987dc800bSAl Viro { 100087dc800bSAl Viro char *s = nd_get_link(nd); 100187dc800bSAl Viro if (!IS_ERR(s)) 100287dc800bSAl Viro kfree(s); 100387dc800bSAl Viro } 100487dc800bSAl Viro EXPORT_SYMBOL(kfree_put_link); 10056987843fSAl Viro 10066987843fSAl Viro /* 10076987843fSAl Viro * nop .set_page_dirty method so that people can use .page_mkwrite on 10086987843fSAl Viro * anon inodes. 10096987843fSAl Viro */ 10106987843fSAl Viro static int anon_set_page_dirty(struct page *page) 10116987843fSAl Viro { 10126987843fSAl Viro return 0; 10136987843fSAl Viro }; 10146987843fSAl Viro 10156987843fSAl Viro /* 10166987843fSAl Viro * A single inode exists for all anon_inode files. Contrary to pipes, 10176987843fSAl Viro * anon_inode inodes have no associated per-instance data, so we need 10186987843fSAl Viro * only allocate one of them. 10196987843fSAl Viro */ 10206987843fSAl Viro struct inode *alloc_anon_inode(struct super_block *s) 10216987843fSAl Viro { 10226987843fSAl Viro static const struct address_space_operations anon_aops = { 10236987843fSAl Viro .set_page_dirty = anon_set_page_dirty, 10246987843fSAl Viro }; 10256987843fSAl Viro struct inode *inode = new_inode_pseudo(s); 10266987843fSAl Viro 10276987843fSAl Viro if (!inode) 10286987843fSAl Viro return ERR_PTR(-ENOMEM); 10296987843fSAl Viro 10306987843fSAl Viro inode->i_ino = get_next_ino(); 10316987843fSAl Viro inode->i_mapping->a_ops = &anon_aops; 10326987843fSAl Viro 10336987843fSAl Viro /* 10346987843fSAl Viro * Mark the inode dirty from the very beginning, 10356987843fSAl Viro * that way it will never be moved to the dirty 10366987843fSAl Viro * list because mark_inode_dirty() will think 10376987843fSAl Viro * that it already _is_ on the dirty list. 10386987843fSAl Viro */ 10396987843fSAl Viro inode->i_state = I_DIRTY; 10406987843fSAl Viro inode->i_mode = S_IRUSR | S_IWUSR; 10416987843fSAl Viro inode->i_uid = current_fsuid(); 10426987843fSAl Viro inode->i_gid = current_fsgid(); 10436987843fSAl Viro inode->i_flags |= S_PRIVATE; 10446987843fSAl Viro inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 10456987843fSAl Viro return inode; 10466987843fSAl Viro } 10476987843fSAl Viro EXPORT_SYMBOL(alloc_anon_inode); 1048