11da177e4SLinus Torvalds /* 2f1adc05eSJeff Dike * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 31da177e4SLinus Torvalds * Licensed under the GPL 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Ported the filesystem routines to 2.5. 61da177e4SLinus Torvalds * 2003-02-10 Petr Baudis <pasky@ucw.cz> 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds #include <linux/fs.h> 102b3b9bb0SJames Hogan #include <linux/magic.h> 111da177e4SLinus Torvalds #include <linux/module.h> 1284b3db04SJeff Dike #include <linux/mm.h> 131da177e4SLinus Torvalds #include <linux/pagemap.h> 141da177e4SLinus Torvalds #include <linux/statfs.h> 155a0e3ad6STejun Heo #include <linux/slab.h> 16dd2cc4dfSMiklos Szeredi #include <linux/seq_file.h> 176966a977SJiri Kosina #include <linux/mount.h> 18d0352d3eSAl Viro #include <linux/namei.h> 191da177e4SLinus Torvalds #include "hostfs.h" 2037185b33SAl Viro #include <init.h> 2137185b33SAl Viro #include <kern.h> 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds struct hostfs_inode_info { 241da177e4SLinus Torvalds int fd; 25aeb5d727SAl Viro fmode_t mode; 261da177e4SLinus Torvalds struct inode vfs_inode; 2769886e67SRichard Weinberger struct mutex open_mutex; 281da177e4SLinus Torvalds }; 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) 311da177e4SLinus Torvalds { 32f1adc05eSJeff Dike return list_entry(inode, struct hostfs_inode_info, vfs_inode); 331da177e4SLinus Torvalds } 341da177e4SLinus Torvalds 35496ad9aaSAl Viro #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file)) 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds /* Changed in hostfs_args before the kernel starts running */ 38a6eb0be6SPaolo 'Blaisorblade' Giarrusso static char *root_ino = ""; 391da177e4SLinus Torvalds static int append = 0; 401da177e4SLinus Torvalds 4192e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops; 4292e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops; 43d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops; 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds #ifndef MODULE 461da177e4SLinus Torvalds static int __init hostfs_args(char *options, int *add) 471da177e4SLinus Torvalds { 481da177e4SLinus Torvalds char *ptr; 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds ptr = strchr(options, ','); 511da177e4SLinus Torvalds if (ptr != NULL) 521da177e4SLinus Torvalds *ptr++ = '\0'; 531da177e4SLinus Torvalds if (*options != '\0') 541da177e4SLinus Torvalds root_ino = options; 551da177e4SLinus Torvalds 561da177e4SLinus Torvalds options = ptr; 571da177e4SLinus Torvalds while (options) { 581da177e4SLinus Torvalds ptr = strchr(options, ','); 591da177e4SLinus Torvalds if (ptr != NULL) 601da177e4SLinus Torvalds *ptr++ = '\0'; 611da177e4SLinus Torvalds if (*options != '\0') { 621da177e4SLinus Torvalds if (!strcmp(options, "append")) 631da177e4SLinus Torvalds append = 1; 641da177e4SLinus Torvalds else printf("hostfs_args - unsupported option - %s\n", 651da177e4SLinus Torvalds options); 661da177e4SLinus Torvalds } 671da177e4SLinus Torvalds options = ptr; 681da177e4SLinus Torvalds } 69f1adc05eSJeff Dike return 0; 701da177e4SLinus Torvalds } 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds __uml_setup("hostfs=", hostfs_args, 731da177e4SLinus Torvalds "hostfs=<root dir>,<flags>,...\n" 741da177e4SLinus Torvalds " This is used to set hostfs parameters. The root directory argument\n" 751da177e4SLinus Torvalds " is used to confine all hostfs mounts to within the specified directory\n" 761da177e4SLinus Torvalds " tree on the host. If this isn't specified, then a user inside UML can\n" 771da177e4SLinus Torvalds " mount anything on the host that's accessible to the user that's running\n" 781da177e4SLinus Torvalds " it.\n" 791da177e4SLinus Torvalds " The only flag currently supported is 'append', which specifies that all\n" 801da177e4SLinus Torvalds " files opened by hostfs will be opened in append mode.\n\n" 811da177e4SLinus Torvalds ); 821da177e4SLinus Torvalds #endif 831da177e4SLinus Torvalds 84e9193059SAl Viro static char *__dentry_name(struct dentry *dentry, char *name) 85e9193059SAl Viro { 86ec2447c2SNick Piggin char *p = dentry_path_raw(dentry, name, PATH_MAX); 87e9193059SAl Viro char *root; 88e9193059SAl Viro size_t len; 89e9193059SAl Viro 90e9193059SAl Viro root = dentry->d_sb->s_fs_info; 91e9193059SAl Viro len = strlen(root); 92e9193059SAl Viro if (IS_ERR(p)) { 93e9193059SAl Viro __putname(name); 94e9193059SAl Viro return NULL; 95e9193059SAl Viro } 96850a496fSAl Viro strlcpy(name, root, PATH_MAX); 97e9193059SAl Viro if (len > p - name) { 98e9193059SAl Viro __putname(name); 99e9193059SAl Viro return NULL; 100e9193059SAl Viro } 101e9193059SAl Viro if (p > name + len) { 102e9193059SAl Viro char *s = name + len; 103e9193059SAl Viro while ((*s++ = *p++) != '\0') 104e9193059SAl Viro ; 105e9193059SAl Viro } 106e9193059SAl Viro return name; 107e9193059SAl Viro } 108e9193059SAl Viro 109c5322220SAl Viro static char *dentry_name(struct dentry *dentry) 1101da177e4SLinus Torvalds { 111e9193059SAl Viro char *name = __getname(); 112e9193059SAl Viro if (!name) 113f1adc05eSJeff Dike return NULL; 1141da177e4SLinus Torvalds 1159dcc5e8aSJames Hogan return __dentry_name(dentry, name); 1161da177e4SLinus Torvalds } 1171da177e4SLinus Torvalds 118c5322220SAl Viro static char *inode_name(struct inode *ino) 1191da177e4SLinus Torvalds { 1201da177e4SLinus Torvalds struct dentry *dentry; 121ec2447c2SNick Piggin char *name; 122ec2447c2SNick Piggin 123ec2447c2SNick Piggin dentry = d_find_alias(ino); 124ec2447c2SNick Piggin if (!dentry) 125e9193059SAl Viro return NULL; 1261da177e4SLinus Torvalds 127ec2447c2SNick Piggin name = dentry_name(dentry); 128ec2447c2SNick Piggin 129ec2447c2SNick Piggin dput(dentry); 130ec2447c2SNick Piggin 131ec2447c2SNick Piggin return name; 1321da177e4SLinus Torvalds } 1331da177e4SLinus Torvalds 1341da177e4SLinus Torvalds static char *follow_link(char *link) 1351da177e4SLinus Torvalds { 1361da177e4SLinus Torvalds int len, n; 1371da177e4SLinus Torvalds char *name, *resolved, *end; 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds len = 64; 1401da177e4SLinus Torvalds while (1) { 1411da177e4SLinus Torvalds n = -ENOMEM; 1421da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1431da177e4SLinus Torvalds if (name == NULL) 1441da177e4SLinus Torvalds goto out; 1451da177e4SLinus Torvalds 146ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1471da177e4SLinus Torvalds if (n < len) 1481da177e4SLinus Torvalds break; 1491da177e4SLinus Torvalds len *= 2; 1501da177e4SLinus Torvalds kfree(name); 1511da177e4SLinus Torvalds } 1521da177e4SLinus Torvalds if (n < 0) 1531da177e4SLinus Torvalds goto out_free; 1541da177e4SLinus Torvalds 1551da177e4SLinus Torvalds if (*name == '/') 156f1adc05eSJeff Dike return name; 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds end = strrchr(link, '/'); 1591da177e4SLinus Torvalds if (end == NULL) 160f1adc05eSJeff Dike return name; 1611da177e4SLinus Torvalds 1621da177e4SLinus Torvalds *(end + 1) = '\0'; 1631da177e4SLinus Torvalds len = strlen(link) + strlen(name) + 1; 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1661da177e4SLinus Torvalds if (resolved == NULL) { 1671da177e4SLinus Torvalds n = -ENOMEM; 1681da177e4SLinus Torvalds goto out_free; 1691da177e4SLinus Torvalds } 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1721da177e4SLinus Torvalds kfree(name); 1731da177e4SLinus Torvalds kfree(link); 174f1adc05eSJeff Dike return resolved; 1751da177e4SLinus Torvalds 1761da177e4SLinus Torvalds out_free: 1771da177e4SLinus Torvalds kfree(name); 1781da177e4SLinus Torvalds out: 179f1adc05eSJeff Dike return ERR_PTR(n); 1801da177e4SLinus Torvalds } 1811da177e4SLinus Torvalds 1820a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1830a370e5dSDavid Howells { 18452b209f7SAl Viro struct inode *inode = new_inode(sb); 1850a370e5dSDavid Howells if (!inode) 1860a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 1870a370e5dSDavid Howells return inode; 1880a370e5dSDavid Howells } 1890a370e5dSDavid Howells 1909e443bc3SJames Hogan static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 1911da177e4SLinus Torvalds { 19284b3db04SJeff Dike /* 19384b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 1941da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 1951da177e4SLinus Torvalds * so we convert them here 1961da177e4SLinus Torvalds */ 1971da177e4SLinus Torvalds int err; 1981da177e4SLinus Torvalds long long f_blocks; 1991da177e4SLinus Torvalds long long f_bfree; 2001da177e4SLinus Torvalds long long f_bavail; 2011da177e4SLinus Torvalds long long f_files; 2021da177e4SLinus Torvalds long long f_ffree; 2031da177e4SLinus Torvalds 204601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2051da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2061da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2071b627d57SRichard Weinberger &sf->f_namelen); 208f1adc05eSJeff Dike if (err) 209f1adc05eSJeff Dike return err; 2101da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2111da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2121da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2131da177e4SLinus Torvalds sf->f_files = f_files; 2141da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2151da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 216f1adc05eSJeff Dike return 0; 2171da177e4SLinus Torvalds } 2181da177e4SLinus Torvalds 2191da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2201da177e4SLinus Torvalds { 2211da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2221da177e4SLinus Torvalds 223371fdab1SJames Hogan hi = kmalloc(sizeof(*hi), GFP_KERNEL); 2241da177e4SLinus Torvalds if (hi == NULL) 225f1adc05eSJeff Dike return NULL; 226601d2c38SAl Viro hi->fd = -1; 227371fdab1SJames Hogan hi->mode = 0; 2281da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 22969886e67SRichard Weinberger mutex_init(&hi->open_mutex); 230f1adc05eSJeff Dike return &hi->vfs_inode; 2311da177e4SLinus Torvalds } 2321da177e4SLinus Torvalds 233e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2341da177e4SLinus Torvalds { 23591b0abe3SJohannes Weiner truncate_inode_pages_final(&inode->i_data); 236dbd5768fSJan Kara clear_inode(inode); 2371da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 2381da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 2391da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 2401da177e4SLinus Torvalds } 2411da177e4SLinus Torvalds } 2421da177e4SLinus Torvalds 243fa0d7e3dSNick Piggin static void hostfs_i_callback(struct rcu_head *head) 244fa0d7e3dSNick Piggin { 245fa0d7e3dSNick Piggin struct inode *inode = container_of(head, struct inode, i_rcu); 246fa0d7e3dSNick Piggin kfree(HOSTFS_I(inode)); 247fa0d7e3dSNick Piggin } 248fa0d7e3dSNick Piggin 2491da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 2501da177e4SLinus Torvalds { 251fa0d7e3dSNick Piggin call_rcu(&inode->i_rcu, hostfs_i_callback); 2521da177e4SLinus Torvalds } 2531da177e4SLinus Torvalds 25434c80b1dSAl Viro static int hostfs_show_options(struct seq_file *seq, struct dentry *root) 255dd2cc4dfSMiklos Szeredi { 25634c80b1dSAl Viro const char *root_path = root->d_sb->s_fs_info; 257dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 258dd2cc4dfSMiklos Szeredi 259dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 260dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 261dd2cc4dfSMiklos Szeredi 262dd2cc4dfSMiklos Szeredi return 0; 263dd2cc4dfSMiklos Szeredi } 264dd2cc4dfSMiklos Szeredi 265ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 2661da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 2671da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 268e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 2691da177e4SLinus Torvalds .statfs = hostfs_statfs, 270dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 2711da177e4SLinus Torvalds }; 2721da177e4SLinus Torvalds 2739e443bc3SJames Hogan static int hostfs_readdir(struct file *file, struct dir_context *ctx) 2741da177e4SLinus Torvalds { 2751da177e4SLinus Torvalds void *dir; 2761da177e4SLinus Torvalds char *name; 2771da177e4SLinus Torvalds unsigned long long next, ino; 2781da177e4SLinus Torvalds int error, len; 2793ee6bd8eSGeert Uytterhoeven unsigned int type; 2801da177e4SLinus Torvalds 281c5322220SAl Viro name = dentry_name(file->f_path.dentry); 282f1adc05eSJeff Dike if (name == NULL) 283f1adc05eSJeff Dike return -ENOMEM; 2841da177e4SLinus Torvalds dir = open_dir(name, &error); 285e9193059SAl Viro __putname(name); 286f1adc05eSJeff Dike if (dir == NULL) 287f1adc05eSJeff Dike return -error; 2888e28bc7eSAl Viro next = ctx->pos; 2893ee6bd8eSGeert Uytterhoeven while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { 2908e28bc7eSAl Viro if (!dir_emit(ctx, name, len, ino, type)) 2918e28bc7eSAl Viro break; 2928e28bc7eSAl Viro ctx->pos = next; 2931da177e4SLinus Torvalds } 2941da177e4SLinus Torvalds close_dir(dir); 295f1adc05eSJeff Dike return 0; 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 2984c6dcafcSRichard Weinberger static int hostfs_open(struct inode *ino, struct file *file) 2991da177e4SLinus Torvalds { 3001da177e4SLinus Torvalds char *name; 301aeb5d727SAl Viro fmode_t mode = 0; 302f8ad850fSAl Viro int err; 303aeb5d727SAl Viro int r = 0, w = 0, fd; 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3061da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 307f1adc05eSJeff Dike return 0; 3081da177e4SLinus Torvalds 309f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 3101da177e4SLinus Torvalds 311f8ad850fSAl Viro retry: 312f8ad850fSAl Viro if (mode & FMODE_READ) 3131da177e4SLinus Torvalds r = 1; 314f8ad850fSAl Viro if (mode & FMODE_WRITE) 3151da177e4SLinus Torvalds w = 1; 3161da177e4SLinus Torvalds if (w) 3171da177e4SLinus Torvalds r = 1; 3181da177e4SLinus Torvalds 319c5322220SAl Viro name = dentry_name(file->f_path.dentry); 3201da177e4SLinus Torvalds if (name == NULL) 321f1adc05eSJeff Dike return -ENOMEM; 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds fd = open_file(name, r, w, append); 324e9193059SAl Viro __putname(name); 325f1adc05eSJeff Dike if (fd < 0) 326f1adc05eSJeff Dike return fd; 327f8ad850fSAl Viro 32869886e67SRichard Weinberger mutex_lock(&HOSTFS_I(ino)->open_mutex); 329f8ad850fSAl Viro /* somebody else had handled it first? */ 330f8ad850fSAl Viro if ((mode & HOSTFS_I(ino)->mode) == mode) { 33169886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 332af955658SRichard Weinberger close_file(&fd); 333f8ad850fSAl Viro return 0; 334f8ad850fSAl Viro } 335f8ad850fSAl Viro if ((mode | HOSTFS_I(ino)->mode) != mode) { 336f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 33769886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 338f8ad850fSAl Viro close_file(&fd); 339f8ad850fSAl Viro goto retry; 340f8ad850fSAl Viro } 341f8ad850fSAl Viro if (HOSTFS_I(ino)->fd == -1) { 342f8ad850fSAl Viro HOSTFS_I(ino)->fd = fd; 343f8ad850fSAl Viro } else { 344f8ad850fSAl Viro err = replace_file(fd, HOSTFS_I(ino)->fd); 345f8ad850fSAl Viro close_file(&fd); 346f8ad850fSAl Viro if (err < 0) { 34769886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 348f8ad850fSAl Viro return err; 349f8ad850fSAl Viro } 350f8ad850fSAl Viro } 351f8ad850fSAl Viro HOSTFS_I(ino)->mode = mode; 35269886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 3531da177e4SLinus Torvalds 354f1adc05eSJeff Dike return 0; 3551da177e4SLinus Torvalds } 3561da177e4SLinus Torvalds 35765984ff9SRichard Weinberger static int hostfs_file_release(struct inode *inode, struct file *file) 35865984ff9SRichard Weinberger { 35965984ff9SRichard Weinberger filemap_write_and_wait(inode->i_mapping); 36065984ff9SRichard Weinberger 36165984ff9SRichard Weinberger return 0; 36265984ff9SRichard Weinberger } 36365984ff9SRichard Weinberger 3649e443bc3SJames Hogan static int hostfs_fsync(struct file *file, loff_t start, loff_t end, 3659e443bc3SJames Hogan int datasync) 3661da177e4SLinus Torvalds { 36702c24a82SJosef Bacik struct inode *inode = file->f_mapping->host; 36802c24a82SJosef Bacik int ret; 36902c24a82SJosef Bacik 37002c24a82SJosef Bacik ret = filemap_write_and_wait_range(inode->i_mapping, start, end); 37102c24a82SJosef Bacik if (ret) 37202c24a82SJosef Bacik return ret; 37302c24a82SJosef Bacik 37402c24a82SJosef Bacik mutex_lock(&inode->i_mutex); 37502c24a82SJosef Bacik ret = fsync_file(HOSTFS_I(inode)->fd, datasync); 37602c24a82SJosef Bacik mutex_unlock(&inode->i_mutex); 37702c24a82SJosef Bacik 37802c24a82SJosef Bacik return ret; 3791da177e4SLinus Torvalds } 3801da177e4SLinus Torvalds 3814b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3821da177e4SLinus Torvalds .llseek = generic_file_llseek, 383aad4f8bbSAl Viro .read = new_sync_read, 3845ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 385aad4f8bbSAl Viro .read_iter = generic_file_read_iter, 3868174202bSAl Viro .write_iter = generic_file_write_iter, 3878174202bSAl Viro .write = new_sync_write, 3881da177e4SLinus Torvalds .mmap = generic_file_mmap, 3894c6dcafcSRichard Weinberger .open = hostfs_open, 39065984ff9SRichard Weinberger .release = hostfs_file_release, 3911da177e4SLinus Torvalds .fsync = hostfs_fsync, 3921da177e4SLinus Torvalds }; 3931da177e4SLinus Torvalds 3944b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 3951da177e4SLinus Torvalds .llseek = generic_file_llseek, 3968e28bc7eSAl Viro .iterate = hostfs_readdir, 3971da177e4SLinus Torvalds .read = generic_read_dir, 3984c6dcafcSRichard Weinberger .open = hostfs_open, 3994c6dcafcSRichard Weinberger .fsync = hostfs_fsync, 4001da177e4SLinus Torvalds }; 4011da177e4SLinus Torvalds 4029e443bc3SJames Hogan static int hostfs_writepage(struct page *page, struct writeback_control *wbc) 4031da177e4SLinus Torvalds { 4041da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 4051da177e4SLinus Torvalds struct inode *inode = mapping->host; 4061da177e4SLinus Torvalds char *buffer; 4071da177e4SLinus Torvalds unsigned long long base; 4081da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 4091da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 4101da177e4SLinus Torvalds int err; 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds if (page->index >= end_index) 4131da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 4141da177e4SLinus Torvalds 4151da177e4SLinus Torvalds buffer = kmap(page); 4161da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4191da177e4SLinus Torvalds if (err != count) { 4201da177e4SLinus Torvalds ClearPageUptodate(page); 4211da177e4SLinus Torvalds goto out; 4221da177e4SLinus Torvalds } 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds if (base > inode->i_size) 4251da177e4SLinus Torvalds inode->i_size = base; 4261da177e4SLinus Torvalds 4271da177e4SLinus Torvalds if (PageError(page)) 4281da177e4SLinus Torvalds ClearPageError(page); 4291da177e4SLinus Torvalds err = 0; 4301da177e4SLinus Torvalds 4311da177e4SLinus Torvalds out: 4321da177e4SLinus Torvalds kunmap(page); 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds unlock_page(page); 4351da177e4SLinus Torvalds return err; 4361da177e4SLinus Torvalds } 4371da177e4SLinus Torvalds 4389e443bc3SJames Hogan static int hostfs_readpage(struct file *file, struct page *page) 4391da177e4SLinus Torvalds { 4401da177e4SLinus Torvalds char *buffer; 4411da177e4SLinus Torvalds long long start; 44241761ddfSRichard Weinberger int bytes_read, ret; 4431da177e4SLinus Torvalds 4441da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4451da177e4SLinus Torvalds buffer = kmap(page); 44641761ddfSRichard Weinberger bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4471da177e4SLinus Torvalds PAGE_CACHE_SIZE); 44841761ddfSRichard Weinberger if (bytes_read < 0) { 44941761ddfSRichard Weinberger ret = bytes_read; 45084b3db04SJeff Dike goto out; 45141761ddfSRichard Weinberger } 4521da177e4SLinus Torvalds 45341761ddfSRichard Weinberger memset(buffer + bytes_read, 0, PAGE_CACHE_SIZE - bytes_read); 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds flush_dcache_page(page); 4561da177e4SLinus Torvalds SetPageUptodate(page); 4571da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 45841761ddfSRichard Weinberger ret = 0; 4591da177e4SLinus Torvalds out: 4601da177e4SLinus Torvalds kunmap(page); 4611da177e4SLinus Torvalds unlock_page(page); 46241761ddfSRichard Weinberger return ret; 4631da177e4SLinus Torvalds } 4641da177e4SLinus Torvalds 4659e443bc3SJames Hogan static int hostfs_write_begin(struct file *file, struct address_space *mapping, 466ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 467ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4681da177e4SLinus Torvalds { 469ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 470ae361ff4SNick Piggin 47154566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 472ae361ff4SNick Piggin if (!*pagep) 473ae361ff4SNick Piggin return -ENOMEM; 474ae361ff4SNick Piggin return 0; 475ae361ff4SNick Piggin } 476ae361ff4SNick Piggin 4779e443bc3SJames Hogan static int hostfs_write_end(struct file *file, struct address_space *mapping, 478ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 479ae361ff4SNick Piggin struct page *page, void *fsdata) 480ae361ff4SNick Piggin { 481ae361ff4SNick Piggin struct inode *inode = mapping->host; 482ae361ff4SNick Piggin void *buffer; 483ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 4841da177e4SLinus Torvalds int err; 4851da177e4SLinus Torvalds 4861da177e4SLinus Torvalds buffer = kmap(page); 487ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 4881da177e4SLinus Torvalds kunmap(page); 4891da177e4SLinus Torvalds 490ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 491ae361ff4SNick Piggin SetPageUptodate(page); 4921da177e4SLinus Torvalds 49384b3db04SJeff Dike /* 49484b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 495ae361ff4SNick Piggin * i_size against the last byte written. 496ae361ff4SNick Piggin */ 497ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 498ae361ff4SNick Piggin inode->i_size = pos; 499ae361ff4SNick Piggin unlock_page(page); 500ae361ff4SNick Piggin page_cache_release(page); 50130f04a4eSPaolo 'Blaisorblade' Giarrusso 502f1adc05eSJeff Dike return err; 5031da177e4SLinus Torvalds } 5041da177e4SLinus Torvalds 505f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 5061da177e4SLinus Torvalds .writepage = hostfs_writepage, 5071da177e4SLinus Torvalds .readpage = hostfs_readpage, 508ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 509ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 510ae361ff4SNick Piggin .write_end = hostfs_write_end, 5111da177e4SLinus Torvalds }; 5121da177e4SLinus Torvalds 5134754b825SAl Viro static int read_name(struct inode *ino, char *name) 5141da177e4SLinus Torvalds { 5154754b825SAl Viro dev_t rdev; 5164754b825SAl Viro struct hostfs_stat st; 5174754b825SAl Viro int err = stat_file(name, &st, -1); 5184754b825SAl Viro if (err) 5194754b825SAl Viro return err; 5201da177e4SLinus Torvalds 5211da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 5224754b825SAl Viro rdev = MKDEV(st.maj, st.min); 5231da177e4SLinus Torvalds 5244754b825SAl Viro switch (st.mode & S_IFMT) { 5254754b825SAl Viro case S_IFLNK: 526d0352d3eSAl Viro ino->i_op = &hostfs_link_iops; 5274754b825SAl Viro break; 5284754b825SAl Viro case S_IFDIR: 5294754b825SAl Viro ino->i_op = &hostfs_dir_iops; 5304754b825SAl Viro ino->i_fop = &hostfs_dir_fops; 5314754b825SAl Viro break; 5324754b825SAl Viro case S_IFCHR: 5334754b825SAl Viro case S_IFBLK: 5344754b825SAl Viro case S_IFIFO: 5354754b825SAl Viro case S_IFSOCK: 5364754b825SAl Viro init_special_inode(ino, st.mode & S_IFMT, rdev); 5374754b825SAl Viro ino->i_op = &hostfs_iops; 5384754b825SAl Viro break; 5392ad2dca6SRichard Weinberger case S_IFREG: 5404754b825SAl Viro ino->i_op = &hostfs_iops; 5414754b825SAl Viro ino->i_fop = &hostfs_file_fops; 5424754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops; 5432ad2dca6SRichard Weinberger break; 5442ad2dca6SRichard Weinberger default: 5452ad2dca6SRichard Weinberger return -EIO; 5461da177e4SLinus Torvalds } 5474754b825SAl Viro 5484754b825SAl Viro ino->i_ino = st.ino; 5494754b825SAl Viro ino->i_mode = st.mode; 550bfe86848SMiklos Szeredi set_nlink(ino, st.nlink); 55129f82ae5SEric W. Biederman i_uid_write(ino, st.uid); 55229f82ae5SEric W. Biederman i_gid_write(ino, st.gid); 5534754b825SAl Viro ino->i_atime = st.atime; 5544754b825SAl Viro ino->i_mtime = st.mtime; 5554754b825SAl Viro ino->i_ctime = st.ctime; 5564754b825SAl Viro ino->i_size = st.size; 5574754b825SAl Viro ino->i_blocks = st.blocks; 5584754b825SAl Viro return 0; 5591da177e4SLinus Torvalds } 5601da177e4SLinus Torvalds 5619e443bc3SJames Hogan static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 562ebfc3b49SAl Viro bool excl) 5631da177e4SLinus Torvalds { 5641da177e4SLinus Torvalds struct inode *inode; 5651da177e4SLinus Torvalds char *name; 5661da177e4SLinus Torvalds int error, fd; 5671da177e4SLinus Torvalds 5680a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5690a370e5dSDavid Howells if (IS_ERR(inode)) { 5700a370e5dSDavid Howells error = PTR_ERR(inode); 57184b3db04SJeff Dike goto out; 5720a370e5dSDavid Howells } 5731da177e4SLinus Torvalds 5741da177e4SLinus Torvalds error = -ENOMEM; 575c5322220SAl Viro name = dentry_name(dentry); 5761da177e4SLinus Torvalds if (name == NULL) 5771da177e4SLinus Torvalds goto out_put; 5781da177e4SLinus Torvalds 5791da177e4SLinus Torvalds fd = file_create(name, 5801da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 5811da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 5821da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 5834754b825SAl Viro if (fd < 0) 5841da177e4SLinus Torvalds error = fd; 5854754b825SAl Viro else 5865e2df28cSAl Viro error = read_name(inode, name); 5871da177e4SLinus Torvalds 588e9193059SAl Viro __putname(name); 5891da177e4SLinus Torvalds if (error) 5901da177e4SLinus Torvalds goto out_put; 5911da177e4SLinus Torvalds 5921da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 5931da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 5941da177e4SLinus Torvalds d_instantiate(dentry, inode); 595f1adc05eSJeff Dike return 0; 5961da177e4SLinus Torvalds 5971da177e4SLinus Torvalds out_put: 5981da177e4SLinus Torvalds iput(inode); 5991da177e4SLinus Torvalds out: 600f1adc05eSJeff Dike return error; 6011da177e4SLinus Torvalds } 6021da177e4SLinus Torvalds 6039e443bc3SJames Hogan static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 60400cd8dd3SAl Viro unsigned int flags) 6051da177e4SLinus Torvalds { 6061da177e4SLinus Torvalds struct inode *inode; 6071da177e4SLinus Torvalds char *name; 6081da177e4SLinus Torvalds int err; 6091da177e4SLinus Torvalds 6100a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 6110a370e5dSDavid Howells if (IS_ERR(inode)) { 6120a370e5dSDavid Howells err = PTR_ERR(inode); 6131da177e4SLinus Torvalds goto out; 6140a370e5dSDavid Howells } 6151da177e4SLinus Torvalds 6161da177e4SLinus Torvalds err = -ENOMEM; 617c5322220SAl Viro name = dentry_name(dentry); 6181da177e4SLinus Torvalds if (name == NULL) 6191da177e4SLinus Torvalds goto out_put; 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds err = read_name(inode, name); 6225e2df28cSAl Viro 623e9193059SAl Viro __putname(name); 6241da177e4SLinus Torvalds if (err == -ENOENT) { 6251da177e4SLinus Torvalds iput(inode); 6261da177e4SLinus Torvalds inode = NULL; 6271da177e4SLinus Torvalds } 6281da177e4SLinus Torvalds else if (err) 6291da177e4SLinus Torvalds goto out_put; 6301da177e4SLinus Torvalds 6311da177e4SLinus Torvalds d_add(dentry, inode); 632f1adc05eSJeff Dike return NULL; 6331da177e4SLinus Torvalds 6341da177e4SLinus Torvalds out_put: 6351da177e4SLinus Torvalds iput(inode); 6361da177e4SLinus Torvalds out: 637f1adc05eSJeff Dike return ERR_PTR(err); 6381da177e4SLinus Torvalds } 6391da177e4SLinus Torvalds 6409e443bc3SJames Hogan static int hostfs_link(struct dentry *to, struct inode *ino, 6419e443bc3SJames Hogan struct dentry *from) 6421da177e4SLinus Torvalds { 6431da177e4SLinus Torvalds char *from_name, *to_name; 6441da177e4SLinus Torvalds int err; 6451da177e4SLinus Torvalds 646c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 647f1adc05eSJeff Dike return -ENOMEM; 648c5322220SAl Viro to_name = dentry_name(to); 6491da177e4SLinus Torvalds if (to_name == NULL) { 650e9193059SAl Viro __putname(from_name); 651f1adc05eSJeff Dike return -ENOMEM; 6521da177e4SLinus Torvalds } 6531da177e4SLinus Torvalds err = link_file(to_name, from_name); 654e9193059SAl Viro __putname(from_name); 655e9193059SAl Viro __putname(to_name); 656f1adc05eSJeff Dike return err; 6571da177e4SLinus Torvalds } 6581da177e4SLinus Torvalds 6599e443bc3SJames Hogan static int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6601da177e4SLinus Torvalds { 6611da177e4SLinus Torvalds char *file; 6621da177e4SLinus Torvalds int err; 6631da177e4SLinus Torvalds 6641da177e4SLinus Torvalds if (append) 665f1adc05eSJeff Dike return -EPERM; 6661da177e4SLinus Torvalds 667f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL) 668f8d7e187SAl Viro return -ENOMEM; 669f8d7e187SAl Viro 6701da177e4SLinus Torvalds err = unlink_file(file); 671e9193059SAl Viro __putname(file); 672f1adc05eSJeff Dike return err; 6731da177e4SLinus Torvalds } 6741da177e4SLinus Torvalds 6759e443bc3SJames Hogan static int hostfs_symlink(struct inode *ino, struct dentry *dentry, 6769e443bc3SJames Hogan const char *to) 6771da177e4SLinus Torvalds { 6781da177e4SLinus Torvalds char *file; 6791da177e4SLinus Torvalds int err; 6801da177e4SLinus Torvalds 681c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 682f1adc05eSJeff Dike return -ENOMEM; 6831da177e4SLinus Torvalds err = make_symlink(file, to); 684e9193059SAl Viro __putname(file); 685f1adc05eSJeff Dike return err; 6861da177e4SLinus Torvalds } 6871da177e4SLinus Torvalds 6889e443bc3SJames Hogan static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode) 6891da177e4SLinus Torvalds { 6901da177e4SLinus Torvalds char *file; 6911da177e4SLinus Torvalds int err; 6921da177e4SLinus Torvalds 693c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 694f1adc05eSJeff Dike return -ENOMEM; 6951da177e4SLinus Torvalds err = do_mkdir(file, mode); 696e9193059SAl Viro __putname(file); 697f1adc05eSJeff Dike return err; 6981da177e4SLinus Torvalds } 6991da177e4SLinus Torvalds 7009e443bc3SJames Hogan static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 7011da177e4SLinus Torvalds { 7021da177e4SLinus Torvalds char *file; 7031da177e4SLinus Torvalds int err; 7041da177e4SLinus Torvalds 705c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 706f1adc05eSJeff Dike return -ENOMEM; 7071da177e4SLinus Torvalds err = do_rmdir(file); 708e9193059SAl Viro __putname(file); 709f1adc05eSJeff Dike return err; 7101da177e4SLinus Torvalds } 7111da177e4SLinus Torvalds 7121a67aafbSAl Viro static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) 7131da177e4SLinus Torvalds { 7141da177e4SLinus Torvalds struct inode *inode; 7151da177e4SLinus Torvalds char *name; 7160a370e5dSDavid Howells int err; 7171da177e4SLinus Torvalds 7180a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7190a370e5dSDavid Howells if (IS_ERR(inode)) { 7200a370e5dSDavid Howells err = PTR_ERR(inode); 7211da177e4SLinus Torvalds goto out; 7220a370e5dSDavid Howells } 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds err = -ENOMEM; 725c5322220SAl Viro name = dentry_name(dentry); 7261da177e4SLinus Torvalds if (name == NULL) 7271da177e4SLinus Torvalds goto out_put; 7281da177e4SLinus Torvalds 7291da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 73088f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 731e9193059SAl Viro if (!err) 7321da177e4SLinus Torvalds goto out_free; 7331da177e4SLinus Torvalds 7341da177e4SLinus Torvalds err = read_name(inode, name); 735e9193059SAl Viro __putname(name); 7365e2df28cSAl Viro if (err) 7375e2df28cSAl Viro goto out_put; 7381da177e4SLinus Torvalds if (err) 7391da177e4SLinus Torvalds goto out_put; 7401da177e4SLinus Torvalds 7411da177e4SLinus Torvalds d_instantiate(dentry, inode); 742f1adc05eSJeff Dike return 0; 7431da177e4SLinus Torvalds 7441da177e4SLinus Torvalds out_free: 745e9193059SAl Viro __putname(name); 7461da177e4SLinus Torvalds out_put: 7471da177e4SLinus Torvalds iput(inode); 7481da177e4SLinus Torvalds out: 749f1adc05eSJeff Dike return err; 7501da177e4SLinus Torvalds } 7511da177e4SLinus Torvalds 7529a423bb6SMiklos Szeredi static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry, 7539a423bb6SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 7549a423bb6SMiklos Szeredi unsigned int flags) 7551da177e4SLinus Torvalds { 7569a423bb6SMiklos Szeredi char *old_name, *new_name; 7571da177e4SLinus Torvalds int err; 7581da177e4SLinus Torvalds 7599a423bb6SMiklos Szeredi if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 7609a423bb6SMiklos Szeredi return -EINVAL; 7619a423bb6SMiklos Szeredi 7629a423bb6SMiklos Szeredi old_name = dentry_name(old_dentry); 7639a423bb6SMiklos Szeredi if (old_name == NULL) 764f1adc05eSJeff Dike return -ENOMEM; 7659a423bb6SMiklos Szeredi new_name = dentry_name(new_dentry); 7669a423bb6SMiklos Szeredi if (new_name == NULL) { 7679a423bb6SMiklos Szeredi __putname(old_name); 768f1adc05eSJeff Dike return -ENOMEM; 7691da177e4SLinus Torvalds } 7709a423bb6SMiklos Szeredi if (!flags) 7719a423bb6SMiklos Szeredi err = rename_file(old_name, new_name); 7729a423bb6SMiklos Szeredi else 7739a423bb6SMiklos Szeredi err = rename2_file(old_name, new_name, flags); 7749a423bb6SMiklos Szeredi 7759a423bb6SMiklos Szeredi __putname(old_name); 7769a423bb6SMiklos Szeredi __putname(new_name); 777f1adc05eSJeff Dike return err; 7781da177e4SLinus Torvalds } 7791da177e4SLinus Torvalds 7809e443bc3SJames Hogan static int hostfs_permission(struct inode *ino, int desired) 7811da177e4SLinus Torvalds { 7821da177e4SLinus Torvalds char *name; 7831da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7841da177e4SLinus Torvalds 78510556cb2SAl Viro if (desired & MAY_NOT_BLOCK) 786b74c79e9SNick Piggin return -ECHILD; 787b74c79e9SNick Piggin 7881da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7891da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7901da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 791c5322220SAl Viro name = inode_name(ino); 792f1adc05eSJeff Dike if (name == NULL) 793f1adc05eSJeff Dike return -ENOMEM; 7941da177e4SLinus Torvalds 7951da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 7961da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 7971da177e4SLinus Torvalds err = 0; 7981da177e4SLinus Torvalds else 7991da177e4SLinus Torvalds err = access_file(name, r, w, x); 800e9193059SAl Viro __putname(name); 8011da177e4SLinus Torvalds if (!err) 8022830ba7fSAl Viro err = generic_permission(ino, desired); 8031da177e4SLinus Torvalds return err; 8041da177e4SLinus Torvalds } 8051da177e4SLinus Torvalds 8069e443bc3SJames Hogan static int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 8071da177e4SLinus Torvalds { 8081025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 8091da177e4SLinus Torvalds struct hostfs_iattr attrs; 8101da177e4SLinus Torvalds char *name; 8111da177e4SLinus Torvalds int err; 8121da177e4SLinus Torvalds 8131025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 8145822b7faSAlberto Bertogli 8151025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 8161da177e4SLinus Torvalds if (err) 8171da177e4SLinus Torvalds return err; 8181da177e4SLinus Torvalds 8191da177e4SLinus Torvalds if (append) 8201da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 8211da177e4SLinus Torvalds 8221da177e4SLinus Torvalds attrs.ia_valid = 0; 8231da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 8241da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 8251da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 8261da177e4SLinus Torvalds } 8271da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8281da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 82929f82ae5SEric W. Biederman attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); 8301da177e4SLinus Torvalds } 8311da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8321da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 83329f82ae5SEric W. Biederman attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); 8341da177e4SLinus Torvalds } 8351da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8361da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8371da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8381da177e4SLinus Torvalds } 8391da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8401da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 8411da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 8421da177e4SLinus Torvalds } 8431da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8441da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 8451da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 8461da177e4SLinus Torvalds } 8471da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8481da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 8491da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 8501da177e4SLinus Torvalds } 8511da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8521da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8531da177e4SLinus Torvalds } 8541da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8551da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8561da177e4SLinus Torvalds } 857c5322220SAl Viro name = dentry_name(dentry); 858f1adc05eSJeff Dike if (name == NULL) 859f1adc05eSJeff Dike return -ENOMEM; 8605822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 861e9193059SAl Viro __putname(name); 8621da177e4SLinus Torvalds if (err) 863f1adc05eSJeff Dike return err; 8641da177e4SLinus Torvalds 8651025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 866bc077320SMarco Stornelli attr->ia_size != i_size_read(inode)) 8673be2be0aSMarco Stornelli truncate_setsize(inode, attr->ia_size); 8681025774cSChristoph Hellwig 8691025774cSChristoph Hellwig setattr_copy(inode, attr); 8701025774cSChristoph Hellwig mark_inode_dirty(inode); 8711025774cSChristoph Hellwig return 0; 8721da177e4SLinus Torvalds } 8731da177e4SLinus Torvalds 87492e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8751da177e4SLinus Torvalds .permission = hostfs_permission, 8761da177e4SLinus Torvalds .setattr = hostfs_setattr, 8771da177e4SLinus Torvalds }; 8781da177e4SLinus Torvalds 87992e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8801da177e4SLinus Torvalds .create = hostfs_create, 8811da177e4SLinus Torvalds .lookup = hostfs_lookup, 8821da177e4SLinus Torvalds .link = hostfs_link, 8831da177e4SLinus Torvalds .unlink = hostfs_unlink, 8841da177e4SLinus Torvalds .symlink = hostfs_symlink, 8851da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8861da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8871da177e4SLinus Torvalds .mknod = hostfs_mknod, 8889a423bb6SMiklos Szeredi .rename2 = hostfs_rename2, 8891da177e4SLinus Torvalds .permission = hostfs_permission, 8901da177e4SLinus Torvalds .setattr = hostfs_setattr, 8911da177e4SLinus Torvalds }; 8921da177e4SLinus Torvalds 893d0352d3eSAl Viro static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) 8941da177e4SLinus Torvalds { 895d0352d3eSAl Viro char *link = __getname(); 896d0352d3eSAl Viro if (link) { 897d0352d3eSAl Viro char *path = dentry_name(dentry); 898d0352d3eSAl Viro int err = -ENOMEM; 899d0352d3eSAl Viro if (path) { 9003b6036d1SAl Viro err = hostfs_do_readlink(path, link, PATH_MAX); 901d0352d3eSAl Viro if (err == PATH_MAX) 9021da177e4SLinus Torvalds err = -E2BIG; 903e9193059SAl Viro __putname(path); 9041da177e4SLinus Torvalds } 905d0352d3eSAl Viro if (err < 0) { 906d0352d3eSAl Viro __putname(link); 907d0352d3eSAl Viro link = ERR_PTR(err); 908d0352d3eSAl Viro } 909d0352d3eSAl Viro } else { 910d0352d3eSAl Viro link = ERR_PTR(-ENOMEM); 9111da177e4SLinus Torvalds } 9121da177e4SLinus Torvalds 913d0352d3eSAl Viro nd_set_link(nd, link); 914d0352d3eSAl Viro return NULL; 915d0352d3eSAl Viro } 916d0352d3eSAl Viro 917d0352d3eSAl Viro static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 918d0352d3eSAl Viro { 919d0352d3eSAl Viro char *s = nd_get_link(nd); 920d0352d3eSAl Viro if (!IS_ERR(s)) 921d0352d3eSAl Viro __putname(s); 922d0352d3eSAl Viro } 923d0352d3eSAl Viro 924d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 925d0352d3eSAl Viro .readlink = generic_readlink, 926d0352d3eSAl Viro .follow_link = hostfs_follow_link, 927d0352d3eSAl Viro .put_link = hostfs_put_link, 9281da177e4SLinus Torvalds }; 9291da177e4SLinus Torvalds 9301da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9311da177e4SLinus Torvalds { 9321da177e4SLinus Torvalds struct inode *root_inode; 93375e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9341da177e4SLinus Torvalds int err; 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds sb->s_blocksize = 1024; 9371da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9381da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9391da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 940b26d4cd3SAl Viro sb->s_d_op = &simple_dentry_operations; 941752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9421da177e4SLinus Torvalds 943a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 94475e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 94575e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9461da177e4SLinus Torvalds 9471da177e4SLinus Torvalds err = -ENOMEM; 948601d2c38SAl Viro sb->s_fs_info = host_root_path = 949601d2c38SAl Viro kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); 95075e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9511da177e4SLinus Torvalds goto out; 9521da177e4SLinus Torvalds 95375e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9541da177e4SLinus Torvalds 95552b209f7SAl Viro root_inode = new_inode(sb); 95652b209f7SAl Viro if (!root_inode) 957601d2c38SAl Viro goto out; 9581da177e4SLinus Torvalds 9594754b825SAl Viro err = read_name(root_inode, host_root_path); 9604754b825SAl Viro if (err) 9614754b825SAl Viro goto out_put; 96252b209f7SAl Viro 9634754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 96452b209f7SAl Viro char *name = follow_link(host_root_path); 96552b209f7SAl Viro if (IS_ERR(name)) 96652b209f7SAl Viro err = PTR_ERR(name); 96752b209f7SAl Viro else 96852b209f7SAl Viro err = read_name(root_inode, name); 96952b209f7SAl Viro kfree(name); 9701da177e4SLinus Torvalds if (err) 9711da177e4SLinus Torvalds goto out_put; 9724754b825SAl Viro } 9731da177e4SLinus Torvalds 9741da177e4SLinus Torvalds err = -ENOMEM; 97548fde701SAl Viro sb->s_root = d_make_root(root_inode); 9761da177e4SLinus Torvalds if (sb->s_root == NULL) 97748fde701SAl Viro goto out; 9781da177e4SLinus Torvalds 979f1adc05eSJeff Dike return 0; 9801da177e4SLinus Torvalds 9811da177e4SLinus Torvalds out_put: 9821da177e4SLinus Torvalds iput(root_inode); 9831da177e4SLinus Torvalds out: 984f1adc05eSJeff Dike return err; 9851da177e4SLinus Torvalds } 9861da177e4SLinus Torvalds 9873c26ff6eSAl Viro static struct dentry *hostfs_read_sb(struct file_system_type *type, 9881da177e4SLinus Torvalds int flags, const char *dev_name, 9893c26ff6eSAl Viro void *data) 9901da177e4SLinus Torvalds { 9913c26ff6eSAl Viro return mount_nodev(type, flags, data, hostfs_fill_sb_common); 9921da177e4SLinus Torvalds } 9931da177e4SLinus Torvalds 994601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 995601d2c38SAl Viro { 996601d2c38SAl Viro kill_anon_super(s); 997601d2c38SAl Viro kfree(s->s_fs_info); 998601d2c38SAl Viro } 999601d2c38SAl Viro 10001da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 10011da177e4SLinus Torvalds .owner = THIS_MODULE, 10021da177e4SLinus Torvalds .name = "hostfs", 10033c26ff6eSAl Viro .mount = hostfs_read_sb, 1004601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 10051da177e4SLinus Torvalds .fs_flags = 0, 10061da177e4SLinus Torvalds }; 10073e64fe5bSEric W. Biederman MODULE_ALIAS_FS("hostfs"); 10081da177e4SLinus Torvalds 10091da177e4SLinus Torvalds static int __init init_hostfs(void) 10101da177e4SLinus Torvalds { 1011f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 10121da177e4SLinus Torvalds } 10131da177e4SLinus Torvalds 10141da177e4SLinus Torvalds static void __exit exit_hostfs(void) 10151da177e4SLinus Torvalds { 10161da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 10171da177e4SLinus Torvalds } 10181da177e4SLinus Torvalds 10191da177e4SLinus Torvalds module_init(init_hostfs) 10201da177e4SLinus Torvalds module_exit(exit_hostfs) 10211da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1022