11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * fs/libfs.c 31da177e4SLinus Torvalds * Library for filesystems writers. 41da177e4SLinus Torvalds */ 51da177e4SLinus Torvalds 6ac13a829SFabian Frederick #include <linux/blkdev.h> 7630d9c47SPaul Gortmaker #include <linux/export.h> 81da177e4SLinus Torvalds #include <linux/pagemap.h> 95a0e3ad6STejun Heo #include <linux/slab.h> 101da177e4SLinus Torvalds #include <linux/mount.h> 111da177e4SLinus Torvalds #include <linux/vfs.h> 127bb46a67Snpiggin@suse.de #include <linux/quotaops.h> 137cf34c76SIngo Molnar #include <linux/mutex.h> 1487dc800bSAl Viro #include <linux/namei.h> 152596110aSChristoph Hellwig #include <linux/exportfs.h> 16d5aacad5SAl Viro #include <linux/writeback.h> 17ff01bb48SAl Viro #include <linux/buffer_head.h> /* sync_mapping_buffers */ 187cf34c76SIngo Molnar 191da177e4SLinus Torvalds #include <asm/uaccess.h> 201da177e4SLinus Torvalds 21a4464dbcSAl Viro #include "internal.h" 22a4464dbcSAl Viro 23da502956SNick Piggin static inline int simple_positive(struct dentry *dentry) 24da502956SNick Piggin { 25da502956SNick Piggin return dentry->d_inode && !d_unhashed(dentry); 26da502956SNick Piggin } 27da502956SNick Piggin 281da177e4SLinus Torvalds int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, 291da177e4SLinus Torvalds struct kstat *stat) 301da177e4SLinus Torvalds { 311da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 321da177e4SLinus Torvalds generic_fillattr(inode, stat); 331da177e4SLinus Torvalds stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); 341da177e4SLinus Torvalds return 0; 351da177e4SLinus Torvalds } 3612f38872SAl Viro EXPORT_SYMBOL(simple_getattr); 371da177e4SLinus Torvalds 38726c3342SDavid Howells int simple_statfs(struct dentry *dentry, struct kstatfs *buf) 391da177e4SLinus Torvalds { 40726c3342SDavid Howells buf->f_type = dentry->d_sb->s_magic; 411da177e4SLinus Torvalds buf->f_bsize = PAGE_CACHE_SIZE; 421da177e4SLinus Torvalds buf->f_namelen = NAME_MAX; 431da177e4SLinus Torvalds return 0; 441da177e4SLinus Torvalds } 4512f38872SAl Viro EXPORT_SYMBOL(simple_statfs); 461da177e4SLinus Torvalds 471da177e4SLinus Torvalds /* 481da177e4SLinus Torvalds * Retaining negative dentries for an in-memory filesystem just wastes 491da177e4SLinus Torvalds * memory and lookup time: arrange for them to be deleted immediately. 501da177e4SLinus Torvalds */ 51b26d4cd3SAl Viro int always_delete_dentry(const struct dentry *dentry) 521da177e4SLinus Torvalds { 531da177e4SLinus Torvalds return 1; 541da177e4SLinus Torvalds } 55b26d4cd3SAl Viro EXPORT_SYMBOL(always_delete_dentry); 56b26d4cd3SAl Viro 57b26d4cd3SAl Viro const struct dentry_operations simple_dentry_operations = { 58b26d4cd3SAl Viro .d_delete = always_delete_dentry, 59b26d4cd3SAl Viro }; 60b26d4cd3SAl Viro EXPORT_SYMBOL(simple_dentry_operations); 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds /* 631da177e4SLinus Torvalds * Lookup the data. This is trivial - if the dentry didn't already 641da177e4SLinus Torvalds * exist, we know it is negative. Set d_op to delete negative dentries. 651da177e4SLinus Torvalds */ 6600cd8dd3SAl Viro struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) 671da177e4SLinus Torvalds { 681da177e4SLinus Torvalds if (dentry->d_name.len > NAME_MAX) 691da177e4SLinus Torvalds return ERR_PTR(-ENAMETOOLONG); 7074931da7SAl Viro if (!dentry->d_sb->s_d_op) 71fb045adbSNick Piggin d_set_d_op(dentry, &simple_dentry_operations); 721da177e4SLinus Torvalds d_add(dentry, NULL); 731da177e4SLinus Torvalds return NULL; 741da177e4SLinus Torvalds } 7512f38872SAl Viro EXPORT_SYMBOL(simple_lookup); 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds int dcache_dir_open(struct inode *inode, struct file *file) 781da177e4SLinus Torvalds { 7926fe5750SLinus Torvalds static struct qstr cursor_name = QSTR_INIT(".", 1); 801da177e4SLinus Torvalds 810f7fc9e4SJosef "Jeff" Sipek file->private_data = d_alloc(file->f_path.dentry, &cursor_name); 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds return file->private_data ? 0 : -ENOMEM; 841da177e4SLinus Torvalds } 8512f38872SAl Viro EXPORT_SYMBOL(dcache_dir_open); 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds int dcache_dir_close(struct inode *inode, struct file *file) 881da177e4SLinus Torvalds { 891da177e4SLinus Torvalds dput(file->private_data); 901da177e4SLinus Torvalds return 0; 911da177e4SLinus Torvalds } 9212f38872SAl Viro EXPORT_SYMBOL(dcache_dir_close); 931da177e4SLinus Torvalds 94965c8e59SAndrew Morton loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) 951da177e4SLinus Torvalds { 962fd6b7f5SNick Piggin struct dentry *dentry = file->f_path.dentry; 972fd6b7f5SNick Piggin mutex_lock(&dentry->d_inode->i_mutex); 98965c8e59SAndrew Morton switch (whence) { 991da177e4SLinus Torvalds case 1: 1001da177e4SLinus Torvalds offset += file->f_pos; 1011da177e4SLinus Torvalds case 0: 1021da177e4SLinus Torvalds if (offset >= 0) 1031da177e4SLinus Torvalds break; 1041da177e4SLinus Torvalds default: 1052fd6b7f5SNick Piggin mutex_unlock(&dentry->d_inode->i_mutex); 1061da177e4SLinus Torvalds return -EINVAL; 1071da177e4SLinus Torvalds } 1081da177e4SLinus Torvalds if (offset != file->f_pos) { 1091da177e4SLinus Torvalds file->f_pos = offset; 1101da177e4SLinus Torvalds if (file->f_pos >= 2) { 1111da177e4SLinus Torvalds struct list_head *p; 1121da177e4SLinus Torvalds struct dentry *cursor = file->private_data; 1131da177e4SLinus Torvalds loff_t n = file->f_pos - 2; 1141da177e4SLinus Torvalds 1152fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1162fd6b7f5SNick Piggin /* d_lock not required for cursor */ 117946e51f2SAl Viro list_del(&cursor->d_child); 1182fd6b7f5SNick Piggin p = dentry->d_subdirs.next; 1192fd6b7f5SNick Piggin while (n && p != &dentry->d_subdirs) { 1201da177e4SLinus Torvalds struct dentry *next; 121946e51f2SAl Viro next = list_entry(p, struct dentry, d_child); 1222fd6b7f5SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 123da502956SNick Piggin if (simple_positive(next)) 1241da177e4SLinus Torvalds n--; 125da502956SNick Piggin spin_unlock(&next->d_lock); 1261da177e4SLinus Torvalds p = p->next; 1271da177e4SLinus Torvalds } 128946e51f2SAl Viro list_add_tail(&cursor->d_child, p); 1292fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds } 1322fd6b7f5SNick Piggin mutex_unlock(&dentry->d_inode->i_mutex); 1331da177e4SLinus Torvalds return offset; 1341da177e4SLinus Torvalds } 13512f38872SAl Viro EXPORT_SYMBOL(dcache_dir_lseek); 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds /* Relationship between i_mode and the DT_xxx types */ 1381da177e4SLinus Torvalds static inline unsigned char dt_type(struct inode *inode) 1391da177e4SLinus Torvalds { 1401da177e4SLinus Torvalds return (inode->i_mode >> 12) & 15; 1411da177e4SLinus Torvalds } 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds /* 1441da177e4SLinus Torvalds * Directory is locked and all positive dentries in it are safe, since 1451da177e4SLinus Torvalds * for ramfs-type trees they can't go away without unlink() or rmdir(), 1461da177e4SLinus Torvalds * both impossible due to the lock on directory. 1471da177e4SLinus Torvalds */ 1481da177e4SLinus Torvalds 1495f99f4e7SAl Viro int dcache_readdir(struct file *file, struct dir_context *ctx) 1501da177e4SLinus Torvalds { 1515f99f4e7SAl Viro struct dentry *dentry = file->f_path.dentry; 1525f99f4e7SAl Viro struct dentry *cursor = file->private_data; 153946e51f2SAl Viro struct list_head *p, *q = &cursor->d_child; 1541da177e4SLinus Torvalds 1555f99f4e7SAl Viro if (!dir_emit_dots(file, ctx)) 1565f99f4e7SAl Viro return 0; 1572fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1585f99f4e7SAl Viro if (ctx->pos == 2) 1591bfba4e8SAkinobu Mita list_move(q, &dentry->d_subdirs); 1601bfba4e8SAkinobu Mita 1611da177e4SLinus Torvalds for (p = q->next; p != &dentry->d_subdirs; p = p->next) { 162946e51f2SAl Viro struct dentry *next = list_entry(p, struct dentry, d_child); 163da502956SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 164da502956SNick Piggin if (!simple_positive(next)) { 165da502956SNick Piggin spin_unlock(&next->d_lock); 1661da177e4SLinus Torvalds continue; 167da502956SNick Piggin } 1681da177e4SLinus Torvalds 169da502956SNick Piggin spin_unlock(&next->d_lock); 1702fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1715f99f4e7SAl Viro if (!dir_emit(ctx, next->d_name.name, next->d_name.len, 1725f99f4e7SAl Viro next->d_inode->i_ino, dt_type(next->d_inode))) 1731da177e4SLinus Torvalds return 0; 1742fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 1752fd6b7f5SNick Piggin spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); 1761da177e4SLinus Torvalds /* next is still alive */ 1771bfba4e8SAkinobu Mita list_move(q, p); 1782fd6b7f5SNick Piggin spin_unlock(&next->d_lock); 1791da177e4SLinus Torvalds p = q; 1805f99f4e7SAl Viro ctx->pos++; 1811da177e4SLinus Torvalds } 1822fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 1831da177e4SLinus Torvalds return 0; 1841da177e4SLinus Torvalds } 18512f38872SAl Viro EXPORT_SYMBOL(dcache_readdir); 1861da177e4SLinus Torvalds 1871da177e4SLinus Torvalds ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) 1881da177e4SLinus Torvalds { 1891da177e4SLinus Torvalds return -EISDIR; 1901da177e4SLinus Torvalds } 19112f38872SAl Viro EXPORT_SYMBOL(generic_read_dir); 1921da177e4SLinus Torvalds 1934b6f5d20SArjan van de Ven const struct file_operations simple_dir_operations = { 1941da177e4SLinus Torvalds .open = dcache_dir_open, 1951da177e4SLinus Torvalds .release = dcache_dir_close, 1961da177e4SLinus Torvalds .llseek = dcache_dir_lseek, 1971da177e4SLinus Torvalds .read = generic_read_dir, 1985f99f4e7SAl Viro .iterate = dcache_readdir, 1991b061d92SChristoph Hellwig .fsync = noop_fsync, 2001da177e4SLinus Torvalds }; 20112f38872SAl Viro EXPORT_SYMBOL(simple_dir_operations); 2021da177e4SLinus Torvalds 20392e1d5beSArjan van de Ven const struct inode_operations simple_dir_inode_operations = { 2041da177e4SLinus Torvalds .lookup = simple_lookup, 2051da177e4SLinus Torvalds }; 20612f38872SAl Viro EXPORT_SYMBOL(simple_dir_inode_operations); 2071da177e4SLinus Torvalds 208759b9775SHugh Dickins static const struct super_operations simple_super_operations = { 209759b9775SHugh Dickins .statfs = simple_statfs, 210759b9775SHugh Dickins }; 211759b9775SHugh Dickins 2121da177e4SLinus Torvalds /* 2131da177e4SLinus Torvalds * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that 2141da177e4SLinus Torvalds * will never be mountable) 2151da177e4SLinus Torvalds */ 21651139adaSAl Viro struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, 217c74a1cbbSAl Viro const struct super_operations *ops, 218c74a1cbbSAl Viro const struct dentry_operations *dops, unsigned long magic) 2191da177e4SLinus Torvalds { 2209249e17fSDavid Howells struct super_block *s; 2211da177e4SLinus Torvalds struct dentry *dentry; 2221da177e4SLinus Torvalds struct inode *root; 22326fe5750SLinus Torvalds struct qstr d_name = QSTR_INIT(name, strlen(name)); 2241da177e4SLinus Torvalds 2259249e17fSDavid Howells s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); 2261da177e4SLinus Torvalds if (IS_ERR(s)) 22751139adaSAl Viro return ERR_CAST(s); 2281da177e4SLinus Torvalds 22989a4eb4bSJeff Layton s->s_maxbytes = MAX_LFS_FILESIZE; 2303971e1a9SAlex Nixon s->s_blocksize = PAGE_SIZE; 2313971e1a9SAlex Nixon s->s_blocksize_bits = PAGE_SHIFT; 2321da177e4SLinus Torvalds s->s_magic = magic; 233759b9775SHugh Dickins s->s_op = ops ? ops : &simple_super_operations; 2341da177e4SLinus Torvalds s->s_time_gran = 1; 2351da177e4SLinus Torvalds root = new_inode(s); 2361da177e4SLinus Torvalds if (!root) 2371da177e4SLinus Torvalds goto Enomem; 2381a1c9bb4SJeff Layton /* 2391a1c9bb4SJeff Layton * since this is the first inode, make it number 1. New inodes created 2401a1c9bb4SJeff Layton * after this must take care not to collide with it (by passing 2411a1c9bb4SJeff Layton * max_reserved of 1 to iunique). 2421a1c9bb4SJeff Layton */ 2431a1c9bb4SJeff Layton root->i_ino = 1; 2441da177e4SLinus Torvalds root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; 2451da177e4SLinus Torvalds root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; 246a4464dbcSAl Viro dentry = __d_alloc(s, &d_name); 2471da177e4SLinus Torvalds if (!dentry) { 2481da177e4SLinus Torvalds iput(root); 2491da177e4SLinus Torvalds goto Enomem; 2501da177e4SLinus Torvalds } 2511da177e4SLinus Torvalds d_instantiate(dentry, root); 2521da177e4SLinus Torvalds s->s_root = dentry; 253c74a1cbbSAl Viro s->s_d_op = dops; 2541da177e4SLinus Torvalds s->s_flags |= MS_ACTIVE; 25551139adaSAl Viro return dget(s->s_root); 2561da177e4SLinus Torvalds 2571da177e4SLinus Torvalds Enomem: 2586f5bbff9SAl Viro deactivate_locked_super(s); 25951139adaSAl Viro return ERR_PTR(-ENOMEM); 2601da177e4SLinus Torvalds } 26112f38872SAl Viro EXPORT_SYMBOL(mount_pseudo); 2621da177e4SLinus Torvalds 26320955e89SStephen Boyd int simple_open(struct inode *inode, struct file *file) 26420955e89SStephen Boyd { 26520955e89SStephen Boyd if (inode->i_private) 26620955e89SStephen Boyd file->private_data = inode->i_private; 26720955e89SStephen Boyd return 0; 26820955e89SStephen Boyd } 26912f38872SAl Viro EXPORT_SYMBOL(simple_open); 27020955e89SStephen Boyd 2711da177e4SLinus Torvalds int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) 2721da177e4SLinus Torvalds { 2731da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 2741da177e4SLinus Torvalds 2751da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 276d8c76e6fSDave Hansen inc_nlink(inode); 2777de9c6eeSAl Viro ihold(inode); 2781da177e4SLinus Torvalds dget(dentry); 2791da177e4SLinus Torvalds d_instantiate(dentry, inode); 2801da177e4SLinus Torvalds return 0; 2811da177e4SLinus Torvalds } 28212f38872SAl Viro EXPORT_SYMBOL(simple_link); 2831da177e4SLinus Torvalds 2841da177e4SLinus Torvalds int simple_empty(struct dentry *dentry) 2851da177e4SLinus Torvalds { 2861da177e4SLinus Torvalds struct dentry *child; 2871da177e4SLinus Torvalds int ret = 0; 2881da177e4SLinus Torvalds 2892fd6b7f5SNick Piggin spin_lock(&dentry->d_lock); 290946e51f2SAl Viro list_for_each_entry(child, &dentry->d_subdirs, d_child) { 291da502956SNick Piggin spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); 292da502956SNick Piggin if (simple_positive(child)) { 293da502956SNick Piggin spin_unlock(&child->d_lock); 2941da177e4SLinus Torvalds goto out; 295da502956SNick Piggin } 296da502956SNick Piggin spin_unlock(&child->d_lock); 297da502956SNick Piggin } 2981da177e4SLinus Torvalds ret = 1; 2991da177e4SLinus Torvalds out: 3002fd6b7f5SNick Piggin spin_unlock(&dentry->d_lock); 3011da177e4SLinus Torvalds return ret; 3021da177e4SLinus Torvalds } 30312f38872SAl Viro EXPORT_SYMBOL(simple_empty); 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds int simple_unlink(struct inode *dir, struct dentry *dentry) 3061da177e4SLinus Torvalds { 3071da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; 3109a53c3a7SDave Hansen drop_nlink(inode); 3111da177e4SLinus Torvalds dput(dentry); 3121da177e4SLinus Torvalds return 0; 3131da177e4SLinus Torvalds } 31412f38872SAl Viro EXPORT_SYMBOL(simple_unlink); 3151da177e4SLinus Torvalds 3161da177e4SLinus Torvalds int simple_rmdir(struct inode *dir, struct dentry *dentry) 3171da177e4SLinus Torvalds { 3181da177e4SLinus Torvalds if (!simple_empty(dentry)) 3191da177e4SLinus Torvalds return -ENOTEMPTY; 3201da177e4SLinus Torvalds 3219a53c3a7SDave Hansen drop_nlink(dentry->d_inode); 3221da177e4SLinus Torvalds simple_unlink(dir, dentry); 3239a53c3a7SDave Hansen drop_nlink(dir); 3241da177e4SLinus Torvalds return 0; 3251da177e4SLinus Torvalds } 32612f38872SAl Viro EXPORT_SYMBOL(simple_rmdir); 3271da177e4SLinus Torvalds 3281da177e4SLinus Torvalds int simple_rename(struct inode *old_dir, struct dentry *old_dentry, 3291da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 3301da177e4SLinus Torvalds { 3311da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 3321da177e4SLinus Torvalds int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds if (!simple_empty(new_dentry)) 3351da177e4SLinus Torvalds return -ENOTEMPTY; 3361da177e4SLinus Torvalds 3371da177e4SLinus Torvalds if (new_dentry->d_inode) { 3381da177e4SLinus Torvalds simple_unlink(new_dir, new_dentry); 339841590ceSAl Viro if (they_are_dirs) { 340841590ceSAl Viro drop_nlink(new_dentry->d_inode); 3419a53c3a7SDave Hansen drop_nlink(old_dir); 342841590ceSAl Viro } 3431da177e4SLinus Torvalds } else if (they_are_dirs) { 3449a53c3a7SDave Hansen drop_nlink(old_dir); 345d8c76e6fSDave Hansen inc_nlink(new_dir); 3461da177e4SLinus Torvalds } 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = 3491da177e4SLinus Torvalds new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds return 0; 3521da177e4SLinus Torvalds } 35312f38872SAl Viro EXPORT_SYMBOL(simple_rename); 3541da177e4SLinus Torvalds 3557bb46a67Snpiggin@suse.de /** 356eef2380cSChristoph Hellwig * simple_setattr - setattr for simple filesystem 3577bb46a67Snpiggin@suse.de * @dentry: dentry 3587bb46a67Snpiggin@suse.de * @iattr: iattr structure 3597bb46a67Snpiggin@suse.de * 3607bb46a67Snpiggin@suse.de * Returns 0 on success, -error on failure. 3617bb46a67Snpiggin@suse.de * 362eef2380cSChristoph Hellwig * simple_setattr is a simple ->setattr implementation without a proper 363eef2380cSChristoph Hellwig * implementation of size changes. 364eef2380cSChristoph Hellwig * 365eef2380cSChristoph Hellwig * It can either be used for in-memory filesystems or special files 366eef2380cSChristoph Hellwig * on simple regular filesystems. Anything that needs to change on-disk 367eef2380cSChristoph Hellwig * or wire state on size changes needs its own setattr method. 3687bb46a67Snpiggin@suse.de */ 3697bb46a67Snpiggin@suse.de int simple_setattr(struct dentry *dentry, struct iattr *iattr) 3707bb46a67Snpiggin@suse.de { 3717bb46a67Snpiggin@suse.de struct inode *inode = dentry->d_inode; 3727bb46a67Snpiggin@suse.de int error; 3737bb46a67Snpiggin@suse.de 3747bb46a67Snpiggin@suse.de error = inode_change_ok(inode, iattr); 3757bb46a67Snpiggin@suse.de if (error) 3767bb46a67Snpiggin@suse.de return error; 3777bb46a67Snpiggin@suse.de 3782c27c65eSChristoph Hellwig if (iattr->ia_valid & ATTR_SIZE) 3792c27c65eSChristoph Hellwig truncate_setsize(inode, iattr->ia_size); 3806a1a90adSChristoph Hellwig setattr_copy(inode, iattr); 381eef2380cSChristoph Hellwig mark_inode_dirty(inode); 382eef2380cSChristoph Hellwig return 0; 3837bb46a67Snpiggin@suse.de } 3847bb46a67Snpiggin@suse.de EXPORT_SYMBOL(simple_setattr); 3857bb46a67Snpiggin@suse.de 3861da177e4SLinus Torvalds int simple_readpage(struct file *file, struct page *page) 3871da177e4SLinus Torvalds { 388c0d92cbcSPekka J Enberg clear_highpage(page); 3891da177e4SLinus Torvalds flush_dcache_page(page); 3901da177e4SLinus Torvalds SetPageUptodate(page); 3911da177e4SLinus Torvalds unlock_page(page); 3921da177e4SLinus Torvalds return 0; 3931da177e4SLinus Torvalds } 39412f38872SAl Viro EXPORT_SYMBOL(simple_readpage); 3951da177e4SLinus Torvalds 396afddba49SNick Piggin int simple_write_begin(struct file *file, struct address_space *mapping, 397afddba49SNick Piggin loff_t pos, unsigned len, unsigned flags, 398afddba49SNick Piggin struct page **pagep, void **fsdata) 399afddba49SNick Piggin { 400afddba49SNick Piggin struct page *page; 401afddba49SNick Piggin pgoff_t index; 402afddba49SNick Piggin 403afddba49SNick Piggin index = pos >> PAGE_CACHE_SHIFT; 404afddba49SNick Piggin 40554566b2cSNick Piggin page = grab_cache_page_write_begin(mapping, index, flags); 406afddba49SNick Piggin if (!page) 407afddba49SNick Piggin return -ENOMEM; 408afddba49SNick Piggin 409afddba49SNick Piggin *pagep = page; 410afddba49SNick Piggin 411193cf4b9SBoaz Harrosh if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { 412193cf4b9SBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 413193cf4b9SBoaz Harrosh 414193cf4b9SBoaz Harrosh zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); 415193cf4b9SBoaz Harrosh } 416193cf4b9SBoaz Harrosh return 0; 417afddba49SNick Piggin } 41812f38872SAl Viro EXPORT_SYMBOL(simple_write_begin); 419afddba49SNick Piggin 420ad2a722fSBoaz Harrosh /** 421ad2a722fSBoaz Harrosh * simple_write_end - .write_end helper for non-block-device FSes 422ad2a722fSBoaz Harrosh * @available: See .write_end of address_space_operations 423ad2a722fSBoaz Harrosh * @file: " 424ad2a722fSBoaz Harrosh * @mapping: " 425ad2a722fSBoaz Harrosh * @pos: " 426ad2a722fSBoaz Harrosh * @len: " 427ad2a722fSBoaz Harrosh * @copied: " 428ad2a722fSBoaz Harrosh * @page: " 429ad2a722fSBoaz Harrosh * @fsdata: " 430ad2a722fSBoaz Harrosh * 431ad2a722fSBoaz Harrosh * simple_write_end does the minimum needed for updating a page after writing is 432ad2a722fSBoaz Harrosh * done. It has the same API signature as the .write_end of 433ad2a722fSBoaz Harrosh * address_space_operations vector. So it can just be set onto .write_end for 434ad2a722fSBoaz Harrosh * FSes that don't need any other processing. i_mutex is assumed to be held. 435ad2a722fSBoaz Harrosh * Block based filesystems should use generic_write_end(). 436ad2a722fSBoaz Harrosh * NOTE: Even though i_size might get updated by this function, mark_inode_dirty 437ad2a722fSBoaz Harrosh * is not called, so a filesystem that actually does store data in .write_inode 438ad2a722fSBoaz Harrosh * should extend on what's done here with a call to mark_inode_dirty() in the 439ad2a722fSBoaz Harrosh * case that i_size has changed. 440ad2a722fSBoaz Harrosh */ 441ad2a722fSBoaz Harrosh int simple_write_end(struct file *file, struct address_space *mapping, 442ad2a722fSBoaz Harrosh loff_t pos, unsigned len, unsigned copied, 443ad2a722fSBoaz Harrosh struct page *page, void *fsdata) 4441da177e4SLinus Torvalds { 4451da177e4SLinus Torvalds struct inode *inode = page->mapping->host; 446ad2a722fSBoaz Harrosh loff_t last_pos = pos + copied; 447ad2a722fSBoaz Harrosh 448ad2a722fSBoaz Harrosh /* zero the stale part of the page if we did a short copy */ 449ad2a722fSBoaz Harrosh if (copied < len) { 450ad2a722fSBoaz Harrosh unsigned from = pos & (PAGE_CACHE_SIZE - 1); 451ad2a722fSBoaz Harrosh 452ad2a722fSBoaz Harrosh zero_user(page, from + copied, len - copied); 453ad2a722fSBoaz Harrosh } 4541da177e4SLinus Torvalds 455955eff5aSNick Piggin if (!PageUptodate(page)) 456955eff5aSNick Piggin SetPageUptodate(page); 4571da177e4SLinus Torvalds /* 4581da177e4SLinus Torvalds * No need to use i_size_read() here, the i_size 4591b1dcc1bSJes Sorensen * cannot change under us because we hold the i_mutex. 4601da177e4SLinus Torvalds */ 461ad2a722fSBoaz Harrosh if (last_pos > inode->i_size) 462ad2a722fSBoaz Harrosh i_size_write(inode, last_pos); 463ad2a722fSBoaz Harrosh 4641da177e4SLinus Torvalds set_page_dirty(page); 465afddba49SNick Piggin unlock_page(page); 466afddba49SNick Piggin page_cache_release(page); 467afddba49SNick Piggin 468afddba49SNick Piggin return copied; 469afddba49SNick Piggin } 47012f38872SAl Viro EXPORT_SYMBOL(simple_write_end); 471afddba49SNick Piggin 4721a1c9bb4SJeff Layton /* 4731a1c9bb4SJeff Layton * the inodes created here are not hashed. If you use iunique to generate 4741a1c9bb4SJeff Layton * unique inode values later for this filesystem, then you must take care 4751a1c9bb4SJeff Layton * to pass it an appropriate max_reserved value to avoid collisions. 4761a1c9bb4SJeff Layton */ 4777d683a09SRoberto Sassu int simple_fill_super(struct super_block *s, unsigned long magic, 4787d683a09SRoberto Sassu struct tree_descr *files) 4791da177e4SLinus Torvalds { 4801da177e4SLinus Torvalds struct inode *inode; 4811da177e4SLinus Torvalds struct dentry *root; 4821da177e4SLinus Torvalds struct dentry *dentry; 4831da177e4SLinus Torvalds int i; 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds s->s_blocksize = PAGE_CACHE_SIZE; 4861da177e4SLinus Torvalds s->s_blocksize_bits = PAGE_CACHE_SHIFT; 4871da177e4SLinus Torvalds s->s_magic = magic; 488759b9775SHugh Dickins s->s_op = &simple_super_operations; 4891da177e4SLinus Torvalds s->s_time_gran = 1; 4901da177e4SLinus Torvalds 4911da177e4SLinus Torvalds inode = new_inode(s); 4921da177e4SLinus Torvalds if (!inode) 4931da177e4SLinus Torvalds return -ENOMEM; 4941a1c9bb4SJeff Layton /* 4951a1c9bb4SJeff Layton * because the root inode is 1, the files array must not contain an 4961a1c9bb4SJeff Layton * entry at index 1 4971a1c9bb4SJeff Layton */ 4981a1c9bb4SJeff Layton inode->i_ino = 1; 4991da177e4SLinus Torvalds inode->i_mode = S_IFDIR | 0755; 5001da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5011da177e4SLinus Torvalds inode->i_op = &simple_dir_inode_operations; 5021da177e4SLinus Torvalds inode->i_fop = &simple_dir_operations; 503bfe86848SMiklos Szeredi set_nlink(inode, 2); 50448fde701SAl Viro root = d_make_root(inode); 50548fde701SAl Viro if (!root) 5061da177e4SLinus Torvalds return -ENOMEM; 5071da177e4SLinus Torvalds for (i = 0; !files->name || files->name[0]; i++, files++) { 5081da177e4SLinus Torvalds if (!files->name) 5091da177e4SLinus Torvalds continue; 5101a1c9bb4SJeff Layton 5111a1c9bb4SJeff Layton /* warn if it tries to conflict with the root inode */ 5121a1c9bb4SJeff Layton if (unlikely(i == 1)) 5131a1c9bb4SJeff Layton printk(KERN_WARNING "%s: %s passed in a files array" 5141a1c9bb4SJeff Layton "with an index of 1!\n", __func__, 5151a1c9bb4SJeff Layton s->s_type->name); 5161a1c9bb4SJeff Layton 5171da177e4SLinus Torvalds dentry = d_alloc_name(root, files->name); 5181da177e4SLinus Torvalds if (!dentry) 5191da177e4SLinus Torvalds goto out; 5201da177e4SLinus Torvalds inode = new_inode(s); 52132096ea1SKonstantin Khlebnikov if (!inode) { 52232096ea1SKonstantin Khlebnikov dput(dentry); 5231da177e4SLinus Torvalds goto out; 52432096ea1SKonstantin Khlebnikov } 5251da177e4SLinus Torvalds inode->i_mode = S_IFREG | files->mode; 5261da177e4SLinus Torvalds inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 5271da177e4SLinus Torvalds inode->i_fop = files->ops; 5281da177e4SLinus Torvalds inode->i_ino = i; 5291da177e4SLinus Torvalds d_add(dentry, inode); 5301da177e4SLinus Torvalds } 5311da177e4SLinus Torvalds s->s_root = root; 5321da177e4SLinus Torvalds return 0; 5331da177e4SLinus Torvalds out: 5341da177e4SLinus Torvalds d_genocide(root); 535640946f2SAl Viro shrink_dcache_parent(root); 5361da177e4SLinus Torvalds dput(root); 5371da177e4SLinus Torvalds return -ENOMEM; 5381da177e4SLinus Torvalds } 53912f38872SAl Viro EXPORT_SYMBOL(simple_fill_super); 5401da177e4SLinus Torvalds 5411da177e4SLinus Torvalds static DEFINE_SPINLOCK(pin_fs_lock); 5421da177e4SLinus Torvalds 5431f5ce9e9STrond Myklebust int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) 5441da177e4SLinus Torvalds { 5451da177e4SLinus Torvalds struct vfsmount *mnt = NULL; 5461da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5471da177e4SLinus Torvalds if (unlikely(!*mount)) { 5481da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5492452992aSAl Viro mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); 5501da177e4SLinus Torvalds if (IS_ERR(mnt)) 5511da177e4SLinus Torvalds return PTR_ERR(mnt); 5521da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5531da177e4SLinus Torvalds if (!*mount) 5541da177e4SLinus Torvalds *mount = mnt; 5551da177e4SLinus Torvalds } 5561da177e4SLinus Torvalds mntget(*mount); 5571da177e4SLinus Torvalds ++*count; 5581da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5591da177e4SLinus Torvalds mntput(mnt); 5601da177e4SLinus Torvalds return 0; 5611da177e4SLinus Torvalds } 56212f38872SAl Viro EXPORT_SYMBOL(simple_pin_fs); 5631da177e4SLinus Torvalds 5641da177e4SLinus Torvalds void simple_release_fs(struct vfsmount **mount, int *count) 5651da177e4SLinus Torvalds { 5661da177e4SLinus Torvalds struct vfsmount *mnt; 5671da177e4SLinus Torvalds spin_lock(&pin_fs_lock); 5681da177e4SLinus Torvalds mnt = *mount; 5691da177e4SLinus Torvalds if (!--*count) 5701da177e4SLinus Torvalds *mount = NULL; 5711da177e4SLinus Torvalds spin_unlock(&pin_fs_lock); 5721da177e4SLinus Torvalds mntput(mnt); 5731da177e4SLinus Torvalds } 57412f38872SAl Viro EXPORT_SYMBOL(simple_release_fs); 5751da177e4SLinus Torvalds 5766d1029b5SAkinobu Mita /** 5776d1029b5SAkinobu Mita * simple_read_from_buffer - copy data from the buffer to user space 5786d1029b5SAkinobu Mita * @to: the user space buffer to read to 5796d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 5806d1029b5SAkinobu Mita * @ppos: the current position in the buffer 5816d1029b5SAkinobu Mita * @from: the buffer to read from 5826d1029b5SAkinobu Mita * @available: the size of the buffer 5836d1029b5SAkinobu Mita * 5846d1029b5SAkinobu Mita * The simple_read_from_buffer() function reads up to @count bytes from the 5856d1029b5SAkinobu Mita * buffer @from at offset @ppos into the user space address starting at @to. 5866d1029b5SAkinobu Mita * 5876d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 5886d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 5896d1029b5SAkinobu Mita **/ 5901da177e4SLinus Torvalds ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, 5911da177e4SLinus Torvalds const void *from, size_t available) 5921da177e4SLinus Torvalds { 5931da177e4SLinus Torvalds loff_t pos = *ppos; 59414be2746SSteven Rostedt size_t ret; 59514be2746SSteven Rostedt 5961da177e4SLinus Torvalds if (pos < 0) 5971da177e4SLinus Torvalds return -EINVAL; 59814be2746SSteven Rostedt if (pos >= available || !count) 5991da177e4SLinus Torvalds return 0; 6001da177e4SLinus Torvalds if (count > available - pos) 6011da177e4SLinus Torvalds count = available - pos; 60214be2746SSteven Rostedt ret = copy_to_user(to, from + pos, count); 60314be2746SSteven Rostedt if (ret == count) 6041da177e4SLinus Torvalds return -EFAULT; 60514be2746SSteven Rostedt count -= ret; 6061da177e4SLinus Torvalds *ppos = pos + count; 6071da177e4SLinus Torvalds return count; 6081da177e4SLinus Torvalds } 60912f38872SAl Viro EXPORT_SYMBOL(simple_read_from_buffer); 6101da177e4SLinus Torvalds 6116d1029b5SAkinobu Mita /** 6126a727b43SJiri Slaby * simple_write_to_buffer - copy data from user space to the buffer 6136a727b43SJiri Slaby * @to: the buffer to write to 6146a727b43SJiri Slaby * @available: the size of the buffer 6156a727b43SJiri Slaby * @ppos: the current position in the buffer 6166a727b43SJiri Slaby * @from: the user space buffer to read from 6176a727b43SJiri Slaby * @count: the maximum number of bytes to read 6186a727b43SJiri Slaby * 6196a727b43SJiri Slaby * The simple_write_to_buffer() function reads up to @count bytes from the user 6206a727b43SJiri Slaby * space address starting at @from into the buffer @to at offset @ppos. 6216a727b43SJiri Slaby * 6226a727b43SJiri Slaby * On success, the number of bytes written is returned and the offset @ppos is 6236a727b43SJiri Slaby * advanced by this number, or negative value is returned on error. 6246a727b43SJiri Slaby **/ 6256a727b43SJiri Slaby ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, 6266a727b43SJiri Slaby const void __user *from, size_t count) 6276a727b43SJiri Slaby { 6286a727b43SJiri Slaby loff_t pos = *ppos; 6296a727b43SJiri Slaby size_t res; 6306a727b43SJiri Slaby 6316a727b43SJiri Slaby if (pos < 0) 6326a727b43SJiri Slaby return -EINVAL; 6336a727b43SJiri Slaby if (pos >= available || !count) 6346a727b43SJiri Slaby return 0; 6356a727b43SJiri Slaby if (count > available - pos) 6366a727b43SJiri Slaby count = available - pos; 6376a727b43SJiri Slaby res = copy_from_user(to + pos, from, count); 6386a727b43SJiri Slaby if (res == count) 6396a727b43SJiri Slaby return -EFAULT; 6406a727b43SJiri Slaby count -= res; 6416a727b43SJiri Slaby *ppos = pos + count; 6426a727b43SJiri Slaby return count; 6436a727b43SJiri Slaby } 64412f38872SAl Viro EXPORT_SYMBOL(simple_write_to_buffer); 6456a727b43SJiri Slaby 6466a727b43SJiri Slaby /** 6476d1029b5SAkinobu Mita * memory_read_from_buffer - copy data from the buffer 6486d1029b5SAkinobu Mita * @to: the kernel space buffer to read to 6496d1029b5SAkinobu Mita * @count: the maximum number of bytes to read 6506d1029b5SAkinobu Mita * @ppos: the current position in the buffer 6516d1029b5SAkinobu Mita * @from: the buffer to read from 6526d1029b5SAkinobu Mita * @available: the size of the buffer 6536d1029b5SAkinobu Mita * 6546d1029b5SAkinobu Mita * The memory_read_from_buffer() function reads up to @count bytes from the 6556d1029b5SAkinobu Mita * buffer @from at offset @ppos into the kernel space address starting at @to. 6566d1029b5SAkinobu Mita * 6576d1029b5SAkinobu Mita * On success, the number of bytes read is returned and the offset @ppos is 6586d1029b5SAkinobu Mita * advanced by this number, or negative value is returned on error. 6596d1029b5SAkinobu Mita **/ 66093b07113SAkinobu Mita ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 66193b07113SAkinobu Mita const void *from, size_t available) 66293b07113SAkinobu Mita { 66393b07113SAkinobu Mita loff_t pos = *ppos; 66493b07113SAkinobu Mita 66593b07113SAkinobu Mita if (pos < 0) 66693b07113SAkinobu Mita return -EINVAL; 66793b07113SAkinobu Mita if (pos >= available) 66893b07113SAkinobu Mita return 0; 66993b07113SAkinobu Mita if (count > available - pos) 67093b07113SAkinobu Mita count = available - pos; 67193b07113SAkinobu Mita memcpy(to, from + pos, count); 67293b07113SAkinobu Mita *ppos = pos + count; 67393b07113SAkinobu Mita 67493b07113SAkinobu Mita return count; 67593b07113SAkinobu Mita } 67612f38872SAl Viro EXPORT_SYMBOL(memory_read_from_buffer); 67793b07113SAkinobu Mita 6781da177e4SLinus Torvalds /* 6791da177e4SLinus Torvalds * Transaction based IO. 6801da177e4SLinus Torvalds * The file expects a single write which triggers the transaction, and then 6811da177e4SLinus Torvalds * possibly a read which collects the result - which is stored in a 6821da177e4SLinus Torvalds * file-local buffer. 6831da177e4SLinus Torvalds */ 68476791ab2SIngo Molnar 68576791ab2SIngo Molnar void simple_transaction_set(struct file *file, size_t n) 68676791ab2SIngo Molnar { 68776791ab2SIngo Molnar struct simple_transaction_argresp *ar = file->private_data; 68876791ab2SIngo Molnar 68976791ab2SIngo Molnar BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); 69076791ab2SIngo Molnar 69176791ab2SIngo Molnar /* 69276791ab2SIngo Molnar * The barrier ensures that ar->size will really remain zero until 69376791ab2SIngo Molnar * ar->data is ready for reading. 69476791ab2SIngo Molnar */ 69576791ab2SIngo Molnar smp_mb(); 69676791ab2SIngo Molnar ar->size = n; 69776791ab2SIngo Molnar } 69812f38872SAl Viro EXPORT_SYMBOL(simple_transaction_set); 69976791ab2SIngo Molnar 7001da177e4SLinus Torvalds char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) 7011da177e4SLinus Torvalds { 7021da177e4SLinus Torvalds struct simple_transaction_argresp *ar; 7031da177e4SLinus Torvalds static DEFINE_SPINLOCK(simple_transaction_lock); 7041da177e4SLinus Torvalds 7051da177e4SLinus Torvalds if (size > SIMPLE_TRANSACTION_LIMIT - 1) 7061da177e4SLinus Torvalds return ERR_PTR(-EFBIG); 7071da177e4SLinus Torvalds 7081da177e4SLinus Torvalds ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); 7091da177e4SLinus Torvalds if (!ar) 7101da177e4SLinus Torvalds return ERR_PTR(-ENOMEM); 7111da177e4SLinus Torvalds 7121da177e4SLinus Torvalds spin_lock(&simple_transaction_lock); 7131da177e4SLinus Torvalds 7141da177e4SLinus Torvalds /* only one write allowed per open */ 7151da177e4SLinus Torvalds if (file->private_data) { 7161da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7171da177e4SLinus Torvalds free_page((unsigned long)ar); 7181da177e4SLinus Torvalds return ERR_PTR(-EBUSY); 7191da177e4SLinus Torvalds } 7201da177e4SLinus Torvalds 7211da177e4SLinus Torvalds file->private_data = ar; 7221da177e4SLinus Torvalds 7231da177e4SLinus Torvalds spin_unlock(&simple_transaction_lock); 7241da177e4SLinus Torvalds 7251da177e4SLinus Torvalds if (copy_from_user(ar->data, buf, size)) 7261da177e4SLinus Torvalds return ERR_PTR(-EFAULT); 7271da177e4SLinus Torvalds 7281da177e4SLinus Torvalds return ar->data; 7291da177e4SLinus Torvalds } 73012f38872SAl Viro EXPORT_SYMBOL(simple_transaction_get); 7311da177e4SLinus Torvalds 7321da177e4SLinus Torvalds ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) 7331da177e4SLinus Torvalds { 7341da177e4SLinus Torvalds struct simple_transaction_argresp *ar = file->private_data; 7351da177e4SLinus Torvalds 7361da177e4SLinus Torvalds if (!ar) 7371da177e4SLinus Torvalds return 0; 7381da177e4SLinus Torvalds return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); 7391da177e4SLinus Torvalds } 74012f38872SAl Viro EXPORT_SYMBOL(simple_transaction_read); 7411da177e4SLinus Torvalds 7421da177e4SLinus Torvalds int simple_transaction_release(struct inode *inode, struct file *file) 7431da177e4SLinus Torvalds { 7441da177e4SLinus Torvalds free_page((unsigned long)file->private_data); 7451da177e4SLinus Torvalds return 0; 7461da177e4SLinus Torvalds } 74712f38872SAl Viro EXPORT_SYMBOL(simple_transaction_release); 7481da177e4SLinus Torvalds 749acaefc25SArnd Bergmann /* Simple attribute files */ 750acaefc25SArnd Bergmann 751acaefc25SArnd Bergmann struct simple_attr { 7528b88b099SChristoph Hellwig int (*get)(void *, u64 *); 7538b88b099SChristoph Hellwig int (*set)(void *, u64); 754acaefc25SArnd Bergmann char get_buf[24]; /* enough to store a u64 and "\n\0" */ 755acaefc25SArnd Bergmann char set_buf[24]; 756acaefc25SArnd Bergmann void *data; 757acaefc25SArnd Bergmann const char *fmt; /* format for read operation */ 7587cf34c76SIngo Molnar struct mutex mutex; /* protects access to these buffers */ 759acaefc25SArnd Bergmann }; 760acaefc25SArnd Bergmann 761acaefc25SArnd Bergmann /* simple_attr_open is called by an actual attribute open file operation 762acaefc25SArnd Bergmann * to set the attribute specific access operations. */ 763acaefc25SArnd Bergmann int simple_attr_open(struct inode *inode, struct file *file, 7648b88b099SChristoph Hellwig int (*get)(void *, u64 *), int (*set)(void *, u64), 765acaefc25SArnd Bergmann const char *fmt) 766acaefc25SArnd Bergmann { 767acaefc25SArnd Bergmann struct simple_attr *attr; 768acaefc25SArnd Bergmann 769acaefc25SArnd Bergmann attr = kmalloc(sizeof(*attr), GFP_KERNEL); 770acaefc25SArnd Bergmann if (!attr) 771acaefc25SArnd Bergmann return -ENOMEM; 772acaefc25SArnd Bergmann 773acaefc25SArnd Bergmann attr->get = get; 774acaefc25SArnd Bergmann attr->set = set; 7758e18e294STheodore Ts'o attr->data = inode->i_private; 776acaefc25SArnd Bergmann attr->fmt = fmt; 7777cf34c76SIngo Molnar mutex_init(&attr->mutex); 778acaefc25SArnd Bergmann 779acaefc25SArnd Bergmann file->private_data = attr; 780acaefc25SArnd Bergmann 781acaefc25SArnd Bergmann return nonseekable_open(inode, file); 782acaefc25SArnd Bergmann } 78312f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_open); 784acaefc25SArnd Bergmann 78574bedc4dSChristoph Hellwig int simple_attr_release(struct inode *inode, struct file *file) 786acaefc25SArnd Bergmann { 787acaefc25SArnd Bergmann kfree(file->private_data); 788acaefc25SArnd Bergmann return 0; 789acaefc25SArnd Bergmann } 79012f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ 791acaefc25SArnd Bergmann 792acaefc25SArnd Bergmann /* read from the buffer that is filled with the get function */ 793acaefc25SArnd Bergmann ssize_t simple_attr_read(struct file *file, char __user *buf, 794acaefc25SArnd Bergmann size_t len, loff_t *ppos) 795acaefc25SArnd Bergmann { 796acaefc25SArnd Bergmann struct simple_attr *attr; 797acaefc25SArnd Bergmann size_t size; 798acaefc25SArnd Bergmann ssize_t ret; 799acaefc25SArnd Bergmann 800acaefc25SArnd Bergmann attr = file->private_data; 801acaefc25SArnd Bergmann 802acaefc25SArnd Bergmann if (!attr->get) 803acaefc25SArnd Bergmann return -EACCES; 804acaefc25SArnd Bergmann 8059261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8069261303aSChristoph Hellwig if (ret) 8079261303aSChristoph Hellwig return ret; 8089261303aSChristoph Hellwig 8098b88b099SChristoph Hellwig if (*ppos) { /* continued read */ 810acaefc25SArnd Bergmann size = strlen(attr->get_buf); 8118b88b099SChristoph Hellwig } else { /* first read */ 8128b88b099SChristoph Hellwig u64 val; 8138b88b099SChristoph Hellwig ret = attr->get(attr->data, &val); 8148b88b099SChristoph Hellwig if (ret) 8158b88b099SChristoph Hellwig goto out; 8168b88b099SChristoph Hellwig 817acaefc25SArnd Bergmann size = scnprintf(attr->get_buf, sizeof(attr->get_buf), 8188b88b099SChristoph Hellwig attr->fmt, (unsigned long long)val); 8198b88b099SChristoph Hellwig } 820acaefc25SArnd Bergmann 821acaefc25SArnd Bergmann ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); 8228b88b099SChristoph Hellwig out: 8237cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 824acaefc25SArnd Bergmann return ret; 825acaefc25SArnd Bergmann } 82612f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_read); 827acaefc25SArnd Bergmann 828acaefc25SArnd Bergmann /* interpret the buffer as a number to call the set function with */ 829acaefc25SArnd Bergmann ssize_t simple_attr_write(struct file *file, const char __user *buf, 830acaefc25SArnd Bergmann size_t len, loff_t *ppos) 831acaefc25SArnd Bergmann { 832acaefc25SArnd Bergmann struct simple_attr *attr; 833acaefc25SArnd Bergmann u64 val; 834acaefc25SArnd Bergmann size_t size; 835acaefc25SArnd Bergmann ssize_t ret; 836acaefc25SArnd Bergmann 837acaefc25SArnd Bergmann attr = file->private_data; 838acaefc25SArnd Bergmann if (!attr->set) 839acaefc25SArnd Bergmann return -EACCES; 840acaefc25SArnd Bergmann 8419261303aSChristoph Hellwig ret = mutex_lock_interruptible(&attr->mutex); 8429261303aSChristoph Hellwig if (ret) 8439261303aSChristoph Hellwig return ret; 8449261303aSChristoph Hellwig 845acaefc25SArnd Bergmann ret = -EFAULT; 846acaefc25SArnd Bergmann size = min(sizeof(attr->set_buf) - 1, len); 847acaefc25SArnd Bergmann if (copy_from_user(attr->set_buf, buf, size)) 848acaefc25SArnd Bergmann goto out; 849acaefc25SArnd Bergmann 850acaefc25SArnd Bergmann attr->set_buf[size] = '\0'; 851f7b88631SAkinobu Mita val = simple_strtoll(attr->set_buf, NULL, 0); 85205cc0ceeSWu Fengguang ret = attr->set(attr->data, val); 85305cc0ceeSWu Fengguang if (ret == 0) 85405cc0ceeSWu Fengguang ret = len; /* on success, claim we got the whole input */ 855acaefc25SArnd Bergmann out: 8567cf34c76SIngo Molnar mutex_unlock(&attr->mutex); 857acaefc25SArnd Bergmann return ret; 858acaefc25SArnd Bergmann } 85912f38872SAl Viro EXPORT_SYMBOL_GPL(simple_attr_write); 860acaefc25SArnd Bergmann 8612596110aSChristoph Hellwig /** 8622596110aSChristoph Hellwig * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation 8632596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8642596110aSChristoph Hellwig * @fid: file handle to convert 8652596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8662596110aSChristoph Hellwig * @fh_type: type of file handle 8672596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 8682596110aSChristoph Hellwig * 8692596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 8702596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 8712596110aSChristoph Hellwig * inode for the object specified in the file handle. 8722596110aSChristoph Hellwig */ 8732596110aSChristoph Hellwig struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, 8742596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 8752596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 8762596110aSChristoph Hellwig { 8772596110aSChristoph Hellwig struct inode *inode = NULL; 8782596110aSChristoph Hellwig 8792596110aSChristoph Hellwig if (fh_len < 2) 8802596110aSChristoph Hellwig return NULL; 8812596110aSChristoph Hellwig 8822596110aSChristoph Hellwig switch (fh_type) { 8832596110aSChristoph Hellwig case FILEID_INO32_GEN: 8842596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 8852596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.ino, fid->i32.gen); 8862596110aSChristoph Hellwig break; 8872596110aSChristoph Hellwig } 8882596110aSChristoph Hellwig 8894ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 8902596110aSChristoph Hellwig } 8912596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_dentry); 8922596110aSChristoph Hellwig 8932596110aSChristoph Hellwig /** 894ca186830SYanchuan Nian * generic_fh_to_parent - generic helper for the fh_to_parent export operation 8952596110aSChristoph Hellwig * @sb: filesystem to do the file handle conversion on 8962596110aSChristoph Hellwig * @fid: file handle to convert 8972596110aSChristoph Hellwig * @fh_len: length of the file handle in bytes 8982596110aSChristoph Hellwig * @fh_type: type of file handle 8992596110aSChristoph Hellwig * @get_inode: filesystem callback to retrieve inode 9002596110aSChristoph Hellwig * 9012596110aSChristoph Hellwig * This function decodes @fid as long as it has one of the well-known 9022596110aSChristoph Hellwig * Linux filehandle types and calls @get_inode on it to retrieve the 9032596110aSChristoph Hellwig * inode for the _parent_ object specified in the file handle if it 9042596110aSChristoph Hellwig * is specified in the file handle, or NULL otherwise. 9052596110aSChristoph Hellwig */ 9062596110aSChristoph Hellwig struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, 9072596110aSChristoph Hellwig int fh_len, int fh_type, struct inode *(*get_inode) 9082596110aSChristoph Hellwig (struct super_block *sb, u64 ino, u32 gen)) 9092596110aSChristoph Hellwig { 9102596110aSChristoph Hellwig struct inode *inode = NULL; 9112596110aSChristoph Hellwig 9122596110aSChristoph Hellwig if (fh_len <= 2) 9132596110aSChristoph Hellwig return NULL; 9142596110aSChristoph Hellwig 9152596110aSChristoph Hellwig switch (fh_type) { 9162596110aSChristoph Hellwig case FILEID_INO32_GEN_PARENT: 9172596110aSChristoph Hellwig inode = get_inode(sb, fid->i32.parent_ino, 9182596110aSChristoph Hellwig (fh_len > 3 ? fid->i32.parent_gen : 0)); 9192596110aSChristoph Hellwig break; 9202596110aSChristoph Hellwig } 9212596110aSChristoph Hellwig 9224ea3ada2SChristoph Hellwig return d_obtain_alias(inode); 9232596110aSChristoph Hellwig } 9242596110aSChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fh_to_parent); 9252596110aSChristoph Hellwig 9261b061d92SChristoph Hellwig /** 927ac13a829SFabian Frederick * __generic_file_fsync - generic fsync implementation for simple filesystems 928ac13a829SFabian Frederick * 9291b061d92SChristoph Hellwig * @file: file to synchronize 930ac13a829SFabian Frederick * @start: start offset in bytes 931ac13a829SFabian Frederick * @end: end offset in bytes (inclusive) 9321b061d92SChristoph Hellwig * @datasync: only synchronize essential metadata if true 9331b061d92SChristoph Hellwig * 9341b061d92SChristoph Hellwig * This is a generic implementation of the fsync method for simple 9351b061d92SChristoph Hellwig * filesystems which track all non-inode metadata in the buffers list 9361b061d92SChristoph Hellwig * hanging off the address_space structure. 9371b061d92SChristoph Hellwig */ 938ac13a829SFabian Frederick int __generic_file_fsync(struct file *file, loff_t start, loff_t end, 93902c24a82SJosef Bacik int datasync) 940d5aacad5SAl Viro { 9417ea80859SChristoph Hellwig struct inode *inode = file->f_mapping->host; 942d5aacad5SAl Viro int err; 943d5aacad5SAl Viro int ret; 944d5aacad5SAl Viro 94502c24a82SJosef Bacik err = filemap_write_and_wait_range(inode->i_mapping, start, end); 94602c24a82SJosef Bacik if (err) 94702c24a82SJosef Bacik return err; 94802c24a82SJosef Bacik 94902c24a82SJosef Bacik mutex_lock(&inode->i_mutex); 950d5aacad5SAl Viro ret = sync_mapping_buffers(inode->i_mapping); 951d5aacad5SAl Viro if (!(inode->i_state & I_DIRTY)) 95202c24a82SJosef Bacik goto out; 953d5aacad5SAl Viro if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) 95402c24a82SJosef Bacik goto out; 955d5aacad5SAl Viro 956c3765016SChristoph Hellwig err = sync_inode_metadata(inode, 1); 957d5aacad5SAl Viro if (ret == 0) 958d5aacad5SAl Viro ret = err; 959ac13a829SFabian Frederick 96002c24a82SJosef Bacik out: 96102c24a82SJosef Bacik mutex_unlock(&inode->i_mutex); 962d5aacad5SAl Viro return ret; 963d5aacad5SAl Viro } 964ac13a829SFabian Frederick EXPORT_SYMBOL(__generic_file_fsync); 965ac13a829SFabian Frederick 966ac13a829SFabian Frederick /** 967ac13a829SFabian Frederick * generic_file_fsync - generic fsync implementation for simple filesystems 968ac13a829SFabian Frederick * with flush 969ac13a829SFabian Frederick * @file: file to synchronize 970ac13a829SFabian Frederick * @start: start offset in bytes 971ac13a829SFabian Frederick * @end: end offset in bytes (inclusive) 972ac13a829SFabian Frederick * @datasync: only synchronize essential metadata if true 973ac13a829SFabian Frederick * 974ac13a829SFabian Frederick */ 975ac13a829SFabian Frederick 976ac13a829SFabian Frederick int generic_file_fsync(struct file *file, loff_t start, loff_t end, 977ac13a829SFabian Frederick int datasync) 978ac13a829SFabian Frederick { 979ac13a829SFabian Frederick struct inode *inode = file->f_mapping->host; 980ac13a829SFabian Frederick int err; 981ac13a829SFabian Frederick 982ac13a829SFabian Frederick err = __generic_file_fsync(file, start, end, datasync); 983ac13a829SFabian Frederick if (err) 984ac13a829SFabian Frederick return err; 985ac13a829SFabian Frederick return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); 986ac13a829SFabian Frederick } 9871b061d92SChristoph Hellwig EXPORT_SYMBOL(generic_file_fsync); 9881b061d92SChristoph Hellwig 98930ca22c7SPatrick J. LoPresti /** 99030ca22c7SPatrick J. LoPresti * generic_check_addressable - Check addressability of file system 99130ca22c7SPatrick J. LoPresti * @blocksize_bits: log of file system block size 99230ca22c7SPatrick J. LoPresti * @num_blocks: number of blocks in file system 99330ca22c7SPatrick J. LoPresti * 99430ca22c7SPatrick J. LoPresti * Determine whether a file system with @num_blocks blocks (and a 99530ca22c7SPatrick J. LoPresti * block size of 2**@blocksize_bits) is addressable by the sector_t 99630ca22c7SPatrick J. LoPresti * and page cache of the system. Return 0 if so and -EFBIG otherwise. 99730ca22c7SPatrick J. LoPresti */ 99830ca22c7SPatrick J. LoPresti int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) 99930ca22c7SPatrick J. LoPresti { 100030ca22c7SPatrick J. LoPresti u64 last_fs_block = num_blocks - 1; 1001a33f13efSJoel Becker u64 last_fs_page = 1002a33f13efSJoel Becker last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); 100330ca22c7SPatrick J. LoPresti 100430ca22c7SPatrick J. LoPresti if (unlikely(num_blocks == 0)) 100530ca22c7SPatrick J. LoPresti return 0; 100630ca22c7SPatrick J. LoPresti 100730ca22c7SPatrick J. LoPresti if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) 100830ca22c7SPatrick J. LoPresti return -EINVAL; 100930ca22c7SPatrick J. LoPresti 1010a33f13efSJoel Becker if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || 1011a33f13efSJoel Becker (last_fs_page > (pgoff_t)(~0ULL))) { 101230ca22c7SPatrick J. LoPresti return -EFBIG; 101330ca22c7SPatrick J. LoPresti } 101430ca22c7SPatrick J. LoPresti return 0; 101530ca22c7SPatrick J. LoPresti } 101630ca22c7SPatrick J. LoPresti EXPORT_SYMBOL(generic_check_addressable); 101730ca22c7SPatrick J. LoPresti 10181b061d92SChristoph Hellwig /* 10191b061d92SChristoph Hellwig * No-op implementation of ->fsync for in-memory filesystems. 10201b061d92SChristoph Hellwig */ 102102c24a82SJosef Bacik int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) 10221b061d92SChristoph Hellwig { 10231b061d92SChristoph Hellwig return 0; 10241b061d92SChristoph Hellwig } 10251b061d92SChristoph Hellwig EXPORT_SYMBOL(noop_fsync); 102687dc800bSAl Viro 102787dc800bSAl Viro void kfree_put_link(struct dentry *dentry, struct nameidata *nd, 102887dc800bSAl Viro void *cookie) 102987dc800bSAl Viro { 103087dc800bSAl Viro char *s = nd_get_link(nd); 103187dc800bSAl Viro if (!IS_ERR(s)) 103287dc800bSAl Viro kfree(s); 103387dc800bSAl Viro } 103487dc800bSAl Viro EXPORT_SYMBOL(kfree_put_link); 10356987843fSAl Viro 10366987843fSAl Viro /* 10376987843fSAl Viro * nop .set_page_dirty method so that people can use .page_mkwrite on 10386987843fSAl Viro * anon inodes. 10396987843fSAl Viro */ 10406987843fSAl Viro static int anon_set_page_dirty(struct page *page) 10416987843fSAl Viro { 10426987843fSAl Viro return 0; 10436987843fSAl Viro }; 10446987843fSAl Viro 10456987843fSAl Viro /* 10466987843fSAl Viro * A single inode exists for all anon_inode files. Contrary to pipes, 10476987843fSAl Viro * anon_inode inodes have no associated per-instance data, so we need 10486987843fSAl Viro * only allocate one of them. 10496987843fSAl Viro */ 10506987843fSAl Viro struct inode *alloc_anon_inode(struct super_block *s) 10516987843fSAl Viro { 10526987843fSAl Viro static const struct address_space_operations anon_aops = { 10536987843fSAl Viro .set_page_dirty = anon_set_page_dirty, 10546987843fSAl Viro }; 10556987843fSAl Viro struct inode *inode = new_inode_pseudo(s); 10566987843fSAl Viro 10576987843fSAl Viro if (!inode) 10586987843fSAl Viro return ERR_PTR(-ENOMEM); 10596987843fSAl Viro 10606987843fSAl Viro inode->i_ino = get_next_ino(); 10616987843fSAl Viro inode->i_mapping->a_ops = &anon_aops; 10626987843fSAl Viro 10636987843fSAl Viro /* 10646987843fSAl Viro * Mark the inode dirty from the very beginning, 10656987843fSAl Viro * that way it will never be moved to the dirty 10666987843fSAl Viro * list because mark_inode_dirty() will think 10676987843fSAl Viro * that it already _is_ on the dirty list. 10686987843fSAl Viro */ 10696987843fSAl Viro inode->i_state = I_DIRTY; 10706987843fSAl Viro inode->i_mode = S_IRUSR | S_IWUSR; 10716987843fSAl Viro inode->i_uid = current_fsuid(); 10726987843fSAl Viro inode->i_gid = current_fsgid(); 10736987843fSAl Viro inode->i_flags |= S_PRIVATE; 10746987843fSAl Viro inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 10756987843fSAl Viro return inode; 10766987843fSAl Viro } 10776987843fSAl Viro EXPORT_SYMBOL(alloc_anon_inode); 10781c994a09SJeff Layton 10791c994a09SJeff Layton /** 10801c994a09SJeff Layton * simple_nosetlease - generic helper for prohibiting leases 10811c994a09SJeff Layton * @filp: file pointer 10821c994a09SJeff Layton * @arg: type of lease to obtain 10831c994a09SJeff Layton * @flp: new lease supplied for insertion 1084e6f5c789SJeff Layton * @priv: private data for lm_setup operation 10851c994a09SJeff Layton * 10861c994a09SJeff Layton * Generic helper for filesystems that do not wish to allow leases to be set. 10871c994a09SJeff Layton * All arguments are ignored and it just returns -EINVAL. 10881c994a09SJeff Layton */ 10891c994a09SJeff Layton int 1090e6f5c789SJeff Layton simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, 1091e6f5c789SJeff Layton void **priv) 10921c994a09SJeff Layton { 10931c994a09SJeff Layton return -EINVAL; 10941c994a09SJeff Layton } 10951c994a09SJeff Layton EXPORT_SYMBOL(simple_nosetlease); 1096