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> 17187c82cbSMatthew Wilcox (Oracle) #include <linux/writeback.h> 186966a977SJiri Kosina #include <linux/mount.h> 19d0352d3eSAl Viro #include <linux/namei.h> 201da177e4SLinus Torvalds #include "hostfs.h" 2137185b33SAl Viro #include <init.h> 2237185b33SAl Viro #include <kern.h> 231da177e4SLinus Torvalds 241da177e4SLinus Torvalds struct hostfs_inode_info { 251da177e4SLinus Torvalds int fd; 26aeb5d727SAl Viro fmode_t mode; 271da177e4SLinus Torvalds struct inode vfs_inode; 2869886e67SRichard Weinberger struct mutex open_mutex; 291da177e4SLinus Torvalds }; 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) 321da177e4SLinus Torvalds { 33f1adc05eSJeff Dike return list_entry(inode, struct hostfs_inode_info, vfs_inode); 341da177e4SLinus Torvalds } 351da177e4SLinus Torvalds 36496ad9aaSAl Viro #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file)) 371da177e4SLinus Torvalds 38a15f1e41SJohannes Berg static struct kmem_cache *hostfs_inode_cache; 39a15f1e41SJohannes Berg 401da177e4SLinus Torvalds /* Changed in hostfs_args before the kernel starts running */ 41a6eb0be6SPaolo 'Blaisorblade' Giarrusso static char *root_ino = ""; 421da177e4SLinus Torvalds static int append = 0; 431da177e4SLinus Torvalds 4492e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops; 4592e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops; 46d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops; 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds #ifndef MODULE 491da177e4SLinus Torvalds static int __init hostfs_args(char *options, int *add) 501da177e4SLinus Torvalds { 511da177e4SLinus Torvalds char *ptr; 521da177e4SLinus Torvalds 531da177e4SLinus Torvalds ptr = strchr(options, ','); 541da177e4SLinus Torvalds if (ptr != NULL) 551da177e4SLinus Torvalds *ptr++ = '\0'; 561da177e4SLinus Torvalds if (*options != '\0') 571da177e4SLinus Torvalds root_ino = options; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds options = ptr; 601da177e4SLinus Torvalds while (options) { 611da177e4SLinus Torvalds ptr = strchr(options, ','); 621da177e4SLinus Torvalds if (ptr != NULL) 631da177e4SLinus Torvalds *ptr++ = '\0'; 641da177e4SLinus Torvalds if (*options != '\0') { 651da177e4SLinus Torvalds if (!strcmp(options, "append")) 661da177e4SLinus Torvalds append = 1; 671da177e4SLinus Torvalds else printf("hostfs_args - unsupported option - %s\n", 681da177e4SLinus Torvalds options); 691da177e4SLinus Torvalds } 701da177e4SLinus Torvalds options = ptr; 711da177e4SLinus Torvalds } 72f1adc05eSJeff Dike return 0; 731da177e4SLinus Torvalds } 741da177e4SLinus Torvalds 751da177e4SLinus Torvalds __uml_setup("hostfs=", hostfs_args, 761da177e4SLinus Torvalds "hostfs=<root dir>,<flags>,...\n" 771da177e4SLinus Torvalds " This is used to set hostfs parameters. The root directory argument\n" 781da177e4SLinus Torvalds " is used to confine all hostfs mounts to within the specified directory\n" 791da177e4SLinus Torvalds " tree on the host. If this isn't specified, then a user inside UML can\n" 801da177e4SLinus Torvalds " mount anything on the host that's accessible to the user that's running\n" 811da177e4SLinus Torvalds " it.\n" 821da177e4SLinus Torvalds " The only flag currently supported is 'append', which specifies that all\n" 831da177e4SLinus Torvalds " files opened by hostfs will be opened in append mode.\n\n" 841da177e4SLinus Torvalds ); 851da177e4SLinus Torvalds #endif 861da177e4SLinus Torvalds 87e9193059SAl Viro static char *__dentry_name(struct dentry *dentry, char *name) 88e9193059SAl Viro { 89ec2447c2SNick Piggin char *p = dentry_path_raw(dentry, name, PATH_MAX); 90e9193059SAl Viro char *root; 91e9193059SAl Viro size_t len; 92e9193059SAl Viro 93e9193059SAl Viro root = dentry->d_sb->s_fs_info; 94e9193059SAl Viro len = strlen(root); 95e9193059SAl Viro if (IS_ERR(p)) { 96e9193059SAl Viro __putname(name); 97e9193059SAl Viro return NULL; 98e9193059SAl Viro } 99aad50b1eSRichard Weinberger 100aad50b1eSRichard Weinberger /* 101aad50b1eSRichard Weinberger * This function relies on the fact that dentry_path_raw() will place 102aad50b1eSRichard Weinberger * the path name at the end of the provided buffer. 103aad50b1eSRichard Weinberger */ 104aad50b1eSRichard Weinberger BUG_ON(p + strlen(p) + 1 != name + PATH_MAX); 105aad50b1eSRichard Weinberger 106850a496fSAl Viro strlcpy(name, root, PATH_MAX); 107e9193059SAl Viro if (len > p - name) { 108e9193059SAl Viro __putname(name); 109e9193059SAl Viro return NULL; 110e9193059SAl Viro } 111c278e81bSRichard Weinberger 112c278e81bSRichard Weinberger if (p > name + len) 113c278e81bSRichard Weinberger strcpy(name + len, p); 114c278e81bSRichard Weinberger 115e9193059SAl Viro return name; 116e9193059SAl Viro } 117e9193059SAl Viro 118c5322220SAl Viro static char *dentry_name(struct dentry *dentry) 1191da177e4SLinus Torvalds { 120e9193059SAl Viro char *name = __getname(); 121e9193059SAl Viro if (!name) 122f1adc05eSJeff Dike return NULL; 1231da177e4SLinus Torvalds 1249dcc5e8aSJames Hogan return __dentry_name(dentry, name); 1251da177e4SLinus Torvalds } 1261da177e4SLinus Torvalds 127c5322220SAl Viro static char *inode_name(struct inode *ino) 1281da177e4SLinus Torvalds { 1291da177e4SLinus Torvalds struct dentry *dentry; 130ec2447c2SNick Piggin char *name; 131ec2447c2SNick Piggin 132ec2447c2SNick Piggin dentry = d_find_alias(ino); 133ec2447c2SNick Piggin if (!dentry) 134e9193059SAl Viro return NULL; 1351da177e4SLinus Torvalds 136ec2447c2SNick Piggin name = dentry_name(dentry); 137ec2447c2SNick Piggin 138ec2447c2SNick Piggin dput(dentry); 139ec2447c2SNick Piggin 140ec2447c2SNick Piggin return name; 1411da177e4SLinus Torvalds } 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds static char *follow_link(char *link) 1441da177e4SLinus Torvalds { 1451da177e4SLinus Torvalds char *name, *resolved, *end; 146b58c4e96SAndy Shevchenko int n; 1471da177e4SLinus Torvalds 1487f6c411cSAl Viro name = kmalloc(PATH_MAX, GFP_KERNEL); 1497c950992SRichard Weinberger if (!name) { 1501da177e4SLinus Torvalds n = -ENOMEM; 1517c950992SRichard Weinberger goto out_free; 1521da177e4SLinus Torvalds } 1537c950992SRichard Weinberger 1547c950992SRichard Weinberger n = hostfs_do_readlink(link, name, PATH_MAX); 1551da177e4SLinus Torvalds if (n < 0) 1561da177e4SLinus Torvalds goto out_free; 1577c950992SRichard Weinberger else if (n == PATH_MAX) { 1587c950992SRichard Weinberger n = -E2BIG; 1597c950992SRichard Weinberger goto out_free; 1607c950992SRichard Weinberger } 1611da177e4SLinus Torvalds 1621da177e4SLinus Torvalds if (*name == '/') 163f1adc05eSJeff Dike return name; 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds end = strrchr(link, '/'); 1661da177e4SLinus Torvalds if (end == NULL) 167f1adc05eSJeff Dike return name; 1681da177e4SLinus Torvalds 1691da177e4SLinus Torvalds *(end + 1) = '\0'; 1701da177e4SLinus Torvalds 171b58c4e96SAndy Shevchenko resolved = kasprintf(GFP_KERNEL, "%s%s", link, name); 1721da177e4SLinus Torvalds if (resolved == NULL) { 1731da177e4SLinus Torvalds n = -ENOMEM; 1741da177e4SLinus Torvalds goto out_free; 1751da177e4SLinus Torvalds } 1761da177e4SLinus Torvalds 1777f6c411cSAl Viro kfree(name); 178f1adc05eSJeff Dike return resolved; 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds out_free: 1817f6c411cSAl Viro kfree(name); 182f1adc05eSJeff Dike return ERR_PTR(n); 1831da177e4SLinus Torvalds } 1841da177e4SLinus Torvalds 1850a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1860a370e5dSDavid Howells { 18752b209f7SAl Viro struct inode *inode = new_inode(sb); 1880a370e5dSDavid Howells if (!inode) 1890a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 1900a370e5dSDavid Howells return inode; 1910a370e5dSDavid Howells } 1920a370e5dSDavid Howells 1939e443bc3SJames Hogan static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 1941da177e4SLinus Torvalds { 19584b3db04SJeff Dike /* 19684b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 1971da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 1981da177e4SLinus Torvalds * so we convert them here 1991da177e4SLinus Torvalds */ 2001da177e4SLinus Torvalds int err; 2011da177e4SLinus Torvalds long long f_blocks; 2021da177e4SLinus Torvalds long long f_bfree; 2031da177e4SLinus Torvalds long long f_bavail; 2041da177e4SLinus Torvalds long long f_files; 2051da177e4SLinus Torvalds long long f_ffree; 2061da177e4SLinus Torvalds 207601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2081da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2091da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2101b627d57SRichard Weinberger &sf->f_namelen); 211f1adc05eSJeff Dike if (err) 212f1adc05eSJeff Dike return err; 2131da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2141da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2151da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2161da177e4SLinus Torvalds sf->f_files = f_files; 2171da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2181da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 219f1adc05eSJeff Dike return 0; 2201da177e4SLinus Torvalds } 2211da177e4SLinus Torvalds 2221da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2231da177e4SLinus Torvalds { 2241da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2251da177e4SLinus Torvalds 226fd60b288SMuchun Song hi = alloc_inode_sb(sb, hostfs_inode_cache, GFP_KERNEL_ACCOUNT); 2271da177e4SLinus Torvalds if (hi == NULL) 228f1adc05eSJeff Dike return NULL; 229601d2c38SAl Viro hi->fd = -1; 230371fdab1SJames Hogan hi->mode = 0; 2311da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 23269886e67SRichard Weinberger mutex_init(&hi->open_mutex); 233f1adc05eSJeff Dike return &hi->vfs_inode; 2341da177e4SLinus Torvalds } 2351da177e4SLinus Torvalds 236e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2371da177e4SLinus Torvalds { 23891b0abe3SJohannes Weiner truncate_inode_pages_final(&inode->i_data); 239dbd5768fSJan Kara clear_inode(inode); 2401da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 2411da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 2421da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 2431da177e4SLinus Torvalds } 2441da177e4SLinus Torvalds } 2451da177e4SLinus Torvalds 24608ccfc5cSAl Viro static void hostfs_free_inode(struct inode *inode) 247fa0d7e3dSNick Piggin { 248a15f1e41SJohannes Berg kmem_cache_free(hostfs_inode_cache, HOSTFS_I(inode)); 249fa0d7e3dSNick Piggin } 250fa0d7e3dSNick Piggin 25134c80b1dSAl Viro static int hostfs_show_options(struct seq_file *seq, struct dentry *root) 252dd2cc4dfSMiklos Szeredi { 25334c80b1dSAl Viro const char *root_path = root->d_sb->s_fs_info; 254dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 255dd2cc4dfSMiklos Szeredi 256dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 257a068acf2SKees Cook seq_show_option(seq, root_path + offset, NULL); 258dd2cc4dfSMiklos Szeredi 2597f74a668SRichard Weinberger if (append) 2607f74a668SRichard Weinberger seq_puts(seq, ",append"); 2617f74a668SRichard Weinberger 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, 26708ccfc5cSAl Viro .free_inode = hostfs_free_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; 2890c9bd636SRichard Weinberger seek_dir(dir, next); 2903ee6bd8eSGeert Uytterhoeven while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { 2918e28bc7eSAl Viro if (!dir_emit(ctx, name, len, ino, type)) 2928e28bc7eSAl Viro break; 2938e28bc7eSAl Viro ctx->pos = next; 2941da177e4SLinus Torvalds } 2951da177e4SLinus Torvalds close_dir(dir); 296f1adc05eSJeff Dike return 0; 2971da177e4SLinus Torvalds } 2981da177e4SLinus Torvalds 2994c6dcafcSRichard Weinberger static int hostfs_open(struct inode *ino, struct file *file) 3001da177e4SLinus Torvalds { 3011da177e4SLinus Torvalds char *name; 302bd1052a2SRichard Weinberger fmode_t mode; 303f8ad850fSAl Viro int err; 304bd1052a2SRichard Weinberger int r, w, fd; 3051da177e4SLinus Torvalds 3061da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3071da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 308f1adc05eSJeff Dike return 0; 3091da177e4SLinus Torvalds 310f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 3111da177e4SLinus Torvalds 312f8ad850fSAl Viro retry: 313a9d1958bSRichard Weinberger r = w = 0; 314a9d1958bSRichard Weinberger 315f8ad850fSAl Viro if (mode & FMODE_READ) 3161da177e4SLinus Torvalds r = 1; 317f8ad850fSAl Viro if (mode & FMODE_WRITE) 318112a5da7SRichard Weinberger r = w = 1; 3191da177e4SLinus Torvalds 320d692d397SAl Viro name = dentry_name(file_dentry(file)); 3211da177e4SLinus Torvalds if (name == NULL) 322f1adc05eSJeff Dike return -ENOMEM; 3231da177e4SLinus Torvalds 3241da177e4SLinus Torvalds fd = open_file(name, r, w, append); 325e9193059SAl Viro __putname(name); 326f1adc05eSJeff Dike if (fd < 0) 327f1adc05eSJeff Dike return fd; 328f8ad850fSAl Viro 32969886e67SRichard Weinberger mutex_lock(&HOSTFS_I(ino)->open_mutex); 330f8ad850fSAl Viro /* somebody else had handled it first? */ 331f8ad850fSAl Viro if ((mode & HOSTFS_I(ino)->mode) == mode) { 33269886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 333af955658SRichard Weinberger close_file(&fd); 334f8ad850fSAl Viro return 0; 335f8ad850fSAl Viro } 336f8ad850fSAl Viro if ((mode | HOSTFS_I(ino)->mode) != mode) { 337f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 33869886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 339f8ad850fSAl Viro close_file(&fd); 340f8ad850fSAl Viro goto retry; 341f8ad850fSAl Viro } 342f8ad850fSAl Viro if (HOSTFS_I(ino)->fd == -1) { 343f8ad850fSAl Viro HOSTFS_I(ino)->fd = fd; 344f8ad850fSAl Viro } else { 345f8ad850fSAl Viro err = replace_file(fd, HOSTFS_I(ino)->fd); 346f8ad850fSAl Viro close_file(&fd); 347f8ad850fSAl Viro if (err < 0) { 34869886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 349f8ad850fSAl Viro return err; 350f8ad850fSAl Viro } 351f8ad850fSAl Viro } 352f8ad850fSAl Viro HOSTFS_I(ino)->mode = mode; 35369886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 3541da177e4SLinus Torvalds 355f1adc05eSJeff Dike return 0; 3561da177e4SLinus Torvalds } 3571da177e4SLinus Torvalds 35865984ff9SRichard Weinberger static int hostfs_file_release(struct inode *inode, struct file *file) 35965984ff9SRichard Weinberger { 36065984ff9SRichard Weinberger filemap_write_and_wait(inode->i_mapping); 36165984ff9SRichard Weinberger 36265984ff9SRichard Weinberger return 0; 36365984ff9SRichard Weinberger } 36465984ff9SRichard Weinberger 3659e443bc3SJames Hogan static int hostfs_fsync(struct file *file, loff_t start, loff_t end, 3669e443bc3SJames Hogan int datasync) 3671da177e4SLinus Torvalds { 36802c24a82SJosef Bacik struct inode *inode = file->f_mapping->host; 36902c24a82SJosef Bacik int ret; 37002c24a82SJosef Bacik 3713b49c9a1SJeff Layton ret = file_write_and_wait_range(file, start, end); 37202c24a82SJosef Bacik if (ret) 37302c24a82SJosef Bacik return ret; 37402c24a82SJosef Bacik 3755955102cSAl Viro inode_lock(inode); 37602c24a82SJosef Bacik ret = fsync_file(HOSTFS_I(inode)->fd, datasync); 3775955102cSAl Viro inode_unlock(inode); 37802c24a82SJosef Bacik 37902c24a82SJosef Bacik return ret; 3801da177e4SLinus Torvalds } 3811da177e4SLinus Torvalds 3824b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3831da177e4SLinus Torvalds .llseek = generic_file_llseek, 3845ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 3851568cb0eSJohannes Berg .splice_write = iter_file_splice_write, 386aad4f8bbSAl Viro .read_iter = generic_file_read_iter, 3878174202bSAl Viro .write_iter = generic_file_write_iter, 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, 396552a9d48SAl Viro .iterate_shared = 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; 407af6aa1b9SRichard Weinberger loff_t base = page_offset(page); 40809cbfeafSKirill A. Shutemov int count = PAGE_SIZE; 40909cbfeafSKirill A. Shutemov int end_index = inode->i_size >> PAGE_SHIFT; 4101da177e4SLinus Torvalds int err; 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds if (page->index >= end_index) 41309cbfeafSKirill A. Shutemov count = inode->i_size & (PAGE_SIZE-1); 4141da177e4SLinus Torvalds 4151da177e4SLinus Torvalds buffer = kmap(page); 4161da177e4SLinus Torvalds 4171da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4181da177e4SLinus Torvalds if (err != count) { 4191da177e4SLinus Torvalds ClearPageUptodate(page); 4201da177e4SLinus Torvalds goto out; 4211da177e4SLinus Torvalds } 4221da177e4SLinus Torvalds 4231da177e4SLinus Torvalds if (base > inode->i_size) 4241da177e4SLinus Torvalds inode->i_size = base; 4251da177e4SLinus Torvalds 4261da177e4SLinus Torvalds if (PageError(page)) 4271da177e4SLinus Torvalds ClearPageError(page); 4281da177e4SLinus Torvalds err = 0; 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds out: 4311da177e4SLinus Torvalds kunmap(page); 4321da177e4SLinus Torvalds 4331da177e4SLinus Torvalds unlock_page(page); 4341da177e4SLinus Torvalds return err; 4351da177e4SLinus Torvalds } 4361da177e4SLinus Torvalds 4379e443bc3SJames Hogan static int hostfs_readpage(struct file *file, struct page *page) 4381da177e4SLinus Torvalds { 4391da177e4SLinus Torvalds char *buffer; 440af6aa1b9SRichard Weinberger loff_t start = page_offset(page); 441b86b413aSRichard Weinberger int bytes_read, ret = 0; 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds buffer = kmap(page); 44441761ddfSRichard Weinberger bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 44509cbfeafSKirill A. Shutemov PAGE_SIZE); 44641761ddfSRichard Weinberger if (bytes_read < 0) { 447b86b413aSRichard Weinberger ClearPageUptodate(page); 448b86b413aSRichard Weinberger SetPageError(page); 44941761ddfSRichard Weinberger ret = bytes_read; 45084b3db04SJeff Dike goto out; 45141761ddfSRichard Weinberger } 4521da177e4SLinus Torvalds 45309cbfeafSKirill A. Shutemov memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read); 4541da177e4SLinus Torvalds 455b86b413aSRichard Weinberger ClearPageError(page); 4561da177e4SLinus Torvalds SetPageUptodate(page); 457b86b413aSRichard Weinberger 4581da177e4SLinus Torvalds out: 459b86b413aSRichard Weinberger flush_dcache_page(page); 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, 466*9d6b0cd7SMatthew Wilcox (Oracle) loff_t pos, unsigned len, 467ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4681da177e4SLinus Torvalds { 46909cbfeafSKirill A. Shutemov pgoff_t index = pos >> PAGE_SHIFT; 470ae361ff4SNick Piggin 471b7446e7cSMatthew Wilcox (Oracle) *pagep = grab_cache_page_write_begin(mapping, index); 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; 48309cbfeafSKirill A. Shutemov unsigned from = pos & (PAGE_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 49009cbfeafSKirill A. Shutemov if (!PageUptodate(page) && err == PAGE_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); 50009cbfeafSKirill A. Shutemov put_page(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, 508187c82cbSMatthew Wilcox (Oracle) .dirty_folio = filemap_dirty_folio, 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); 553bca30265SArnd Bergmann ino->i_atime = (struct timespec64){ st.atime.tv_sec, st.atime.tv_nsec }; 554bca30265SArnd Bergmann ino->i_mtime = (struct timespec64){ st.mtime.tv_sec, st.mtime.tv_nsec }; 555bca30265SArnd Bergmann ino->i_ctime = (struct timespec64){ st.ctime.tv_sec, st.ctime.tv_nsec }; 5564754b825SAl Viro ino->i_size = st.size; 5574754b825SAl Viro ino->i_blocks = st.blocks; 5584754b825SAl Viro return 0; 5591da177e4SLinus Torvalds } 5601da177e4SLinus Torvalds 561549c7297SChristian Brauner static int hostfs_create(struct user_namespace *mnt_userns, struct inode *dir, 562549c7297SChristian Brauner struct dentry *dentry, umode_t mode, 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 579a718c922SRichard Weinberger fd = file_create(name, mode & 0777); 5804754b825SAl Viro if (fd < 0) 5811da177e4SLinus Torvalds error = fd; 5824754b825SAl Viro else 5835e2df28cSAl Viro error = read_name(inode, name); 5841da177e4SLinus Torvalds 585e9193059SAl Viro __putname(name); 5861da177e4SLinus Torvalds if (error) 5871da177e4SLinus Torvalds goto out_put; 5881da177e4SLinus Torvalds 5891da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 5901da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 5911da177e4SLinus Torvalds d_instantiate(dentry, inode); 592f1adc05eSJeff Dike return 0; 5931da177e4SLinus Torvalds 5941da177e4SLinus Torvalds out_put: 5951da177e4SLinus Torvalds iput(inode); 5961da177e4SLinus Torvalds out: 597f1adc05eSJeff Dike return error; 5981da177e4SLinus Torvalds } 5991da177e4SLinus Torvalds 6009e443bc3SJames Hogan static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 60100cd8dd3SAl Viro unsigned int flags) 6021da177e4SLinus Torvalds { 6031da177e4SLinus Torvalds struct inode *inode; 6041da177e4SLinus Torvalds char *name; 6051da177e4SLinus Torvalds int err; 6061da177e4SLinus Torvalds 6070a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 60850f30740SAl Viro if (IS_ERR(inode)) 6091da177e4SLinus Torvalds goto out; 6101da177e4SLinus Torvalds 6111da177e4SLinus Torvalds err = -ENOMEM; 612c5322220SAl Viro name = dentry_name(dentry); 61350f30740SAl Viro if (name) { 6141da177e4SLinus Torvalds err = read_name(inode, name); 615e9193059SAl Viro __putname(name); 6161da177e4SLinus Torvalds } 61750f30740SAl Viro if (err) { 6181da177e4SLinus Torvalds iput(inode); 61950f30740SAl Viro inode = (err == -ENOENT) ? NULL : ERR_PTR(err); 62050f30740SAl Viro } 6211da177e4SLinus Torvalds out: 62250f30740SAl Viro return d_splice_alias(inode, dentry); 6231da177e4SLinus Torvalds } 6241da177e4SLinus Torvalds 6259e443bc3SJames Hogan static int hostfs_link(struct dentry *to, struct inode *ino, 6269e443bc3SJames Hogan struct dentry *from) 6271da177e4SLinus Torvalds { 6281da177e4SLinus Torvalds char *from_name, *to_name; 6291da177e4SLinus Torvalds int err; 6301da177e4SLinus Torvalds 631c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 632f1adc05eSJeff Dike return -ENOMEM; 633c5322220SAl Viro to_name = dentry_name(to); 6341da177e4SLinus Torvalds if (to_name == NULL) { 635e9193059SAl Viro __putname(from_name); 636f1adc05eSJeff Dike return -ENOMEM; 6371da177e4SLinus Torvalds } 6381da177e4SLinus Torvalds err = link_file(to_name, from_name); 639e9193059SAl Viro __putname(from_name); 640e9193059SAl Viro __putname(to_name); 641f1adc05eSJeff Dike return err; 6421da177e4SLinus Torvalds } 6431da177e4SLinus Torvalds 6449e443bc3SJames Hogan static int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6451da177e4SLinus Torvalds { 6461da177e4SLinus Torvalds char *file; 6471da177e4SLinus Torvalds int err; 6481da177e4SLinus Torvalds 6491da177e4SLinus Torvalds if (append) 650f1adc05eSJeff Dike return -EPERM; 6511da177e4SLinus Torvalds 652f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL) 653f8d7e187SAl Viro return -ENOMEM; 654f8d7e187SAl Viro 6551da177e4SLinus Torvalds err = unlink_file(file); 656e9193059SAl Viro __putname(file); 657f1adc05eSJeff Dike return err; 6581da177e4SLinus Torvalds } 6591da177e4SLinus Torvalds 660549c7297SChristian Brauner static int hostfs_symlink(struct user_namespace *mnt_userns, struct inode *ino, 661549c7297SChristian Brauner struct dentry *dentry, const char *to) 6621da177e4SLinus Torvalds { 6631da177e4SLinus Torvalds char *file; 6641da177e4SLinus Torvalds int err; 6651da177e4SLinus Torvalds 666c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 667f1adc05eSJeff Dike return -ENOMEM; 6681da177e4SLinus Torvalds err = make_symlink(file, to); 669e9193059SAl Viro __putname(file); 670f1adc05eSJeff Dike return err; 6711da177e4SLinus Torvalds } 6721da177e4SLinus Torvalds 673549c7297SChristian Brauner static int hostfs_mkdir(struct user_namespace *mnt_userns, struct inode *ino, 674549c7297SChristian Brauner struct dentry *dentry, umode_t mode) 6751da177e4SLinus Torvalds { 6761da177e4SLinus Torvalds char *file; 6771da177e4SLinus Torvalds int err; 6781da177e4SLinus Torvalds 679c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 680f1adc05eSJeff Dike return -ENOMEM; 6811da177e4SLinus Torvalds err = do_mkdir(file, mode); 682e9193059SAl Viro __putname(file); 683f1adc05eSJeff Dike return err; 6841da177e4SLinus Torvalds } 6851da177e4SLinus Torvalds 6869e443bc3SJames Hogan static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 6871da177e4SLinus Torvalds { 6881da177e4SLinus Torvalds char *file; 6891da177e4SLinus Torvalds int err; 6901da177e4SLinus Torvalds 691c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 692f1adc05eSJeff Dike return -ENOMEM; 6936380161cSDominik Brodowski err = hostfs_do_rmdir(file); 694e9193059SAl Viro __putname(file); 695f1adc05eSJeff Dike return err; 6961da177e4SLinus Torvalds } 6971da177e4SLinus Torvalds 698549c7297SChristian Brauner static int hostfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, 699549c7297SChristian Brauner struct dentry *dentry, umode_t mode, dev_t dev) 7001da177e4SLinus Torvalds { 7011da177e4SLinus Torvalds struct inode *inode; 7021da177e4SLinus Torvalds char *name; 7030a370e5dSDavid Howells int err; 7041da177e4SLinus Torvalds 7050a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7060a370e5dSDavid Howells if (IS_ERR(inode)) { 7070a370e5dSDavid Howells err = PTR_ERR(inode); 7081da177e4SLinus Torvalds goto out; 7090a370e5dSDavid Howells } 7101da177e4SLinus Torvalds 7111da177e4SLinus Torvalds err = -ENOMEM; 712c5322220SAl Viro name = dentry_name(dentry); 7131da177e4SLinus Torvalds if (name == NULL) 7141da177e4SLinus Torvalds goto out_put; 7151da177e4SLinus Torvalds 71688f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 7179f2dfda2SVegard Nossum if (err) 7181da177e4SLinus Torvalds goto out_free; 7191da177e4SLinus Torvalds 7201da177e4SLinus Torvalds err = read_name(inode, name); 721e9193059SAl Viro __putname(name); 7225e2df28cSAl Viro if (err) 7235e2df28cSAl Viro goto out_put; 7241da177e4SLinus Torvalds 7251da177e4SLinus Torvalds d_instantiate(dentry, inode); 726f1adc05eSJeff Dike return 0; 7271da177e4SLinus Torvalds 7281da177e4SLinus Torvalds out_free: 729e9193059SAl Viro __putname(name); 7301da177e4SLinus Torvalds out_put: 7311da177e4SLinus Torvalds iput(inode); 7321da177e4SLinus Torvalds out: 733f1adc05eSJeff Dike return err; 7341da177e4SLinus Torvalds } 7351da177e4SLinus Torvalds 736549c7297SChristian Brauner static int hostfs_rename2(struct user_namespace *mnt_userns, 737549c7297SChristian Brauner struct inode *old_dir, struct dentry *old_dentry, 7389a423bb6SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 7399a423bb6SMiklos Szeredi unsigned int flags) 7401da177e4SLinus Torvalds { 7419a423bb6SMiklos Szeredi char *old_name, *new_name; 7421da177e4SLinus Torvalds int err; 7431da177e4SLinus Torvalds 7449a423bb6SMiklos Szeredi if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 7459a423bb6SMiklos Szeredi return -EINVAL; 7469a423bb6SMiklos Szeredi 7479a423bb6SMiklos Szeredi old_name = dentry_name(old_dentry); 7489a423bb6SMiklos Szeredi if (old_name == NULL) 749f1adc05eSJeff Dike return -ENOMEM; 7509a423bb6SMiklos Szeredi new_name = dentry_name(new_dentry); 7519a423bb6SMiklos Szeredi if (new_name == NULL) { 7529a423bb6SMiklos Szeredi __putname(old_name); 753f1adc05eSJeff Dike return -ENOMEM; 7541da177e4SLinus Torvalds } 7559a423bb6SMiklos Szeredi if (!flags) 7569a423bb6SMiklos Szeredi err = rename_file(old_name, new_name); 7579a423bb6SMiklos Szeredi else 7589a423bb6SMiklos Szeredi err = rename2_file(old_name, new_name, flags); 7599a423bb6SMiklos Szeredi 7609a423bb6SMiklos Szeredi __putname(old_name); 7619a423bb6SMiklos Szeredi __putname(new_name); 762f1adc05eSJeff Dike return err; 7631da177e4SLinus Torvalds } 7641da177e4SLinus Torvalds 765549c7297SChristian Brauner static int hostfs_permission(struct user_namespace *mnt_userns, 766549c7297SChristian Brauner struct inode *ino, int desired) 7671da177e4SLinus Torvalds { 7681da177e4SLinus Torvalds char *name; 7691da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7701da177e4SLinus Torvalds 77110556cb2SAl Viro if (desired & MAY_NOT_BLOCK) 772b74c79e9SNick Piggin return -ECHILD; 773b74c79e9SNick Piggin 7741da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7751da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7761da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 777c5322220SAl Viro name = inode_name(ino); 778f1adc05eSJeff Dike if (name == NULL) 779f1adc05eSJeff Dike return -ENOMEM; 7801da177e4SLinus Torvalds 7811da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 7821da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 7831da177e4SLinus Torvalds err = 0; 7841da177e4SLinus Torvalds else 7851da177e4SLinus Torvalds err = access_file(name, r, w, x); 786e9193059SAl Viro __putname(name); 7871da177e4SLinus Torvalds if (!err) 78847291baaSChristian Brauner err = generic_permission(&init_user_ns, ino, desired); 7891da177e4SLinus Torvalds return err; 7901da177e4SLinus Torvalds } 7911da177e4SLinus Torvalds 792549c7297SChristian Brauner static int hostfs_setattr(struct user_namespace *mnt_userns, 793549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr) 7941da177e4SLinus Torvalds { 7952b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 7961da177e4SLinus Torvalds struct hostfs_iattr attrs; 7971da177e4SLinus Torvalds char *name; 7981da177e4SLinus Torvalds int err; 7991da177e4SLinus Torvalds 8001025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 8015822b7faSAlberto Bertogli 8022f221d6fSChristian Brauner err = setattr_prepare(&init_user_ns, dentry, attr); 8031da177e4SLinus Torvalds if (err) 8041da177e4SLinus Torvalds return err; 8051da177e4SLinus Torvalds 8061da177e4SLinus Torvalds if (append) 8071da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 8081da177e4SLinus Torvalds 8091da177e4SLinus Torvalds attrs.ia_valid = 0; 8101da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 8111da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 8121da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 8131da177e4SLinus Torvalds } 8141da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8151da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 81629f82ae5SEric W. Biederman attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); 8171da177e4SLinus Torvalds } 8181da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8191da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 82029f82ae5SEric W. Biederman attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); 8211da177e4SLinus Torvalds } 8221da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8231da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8241da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8251da177e4SLinus Torvalds } 8261da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8271da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 828bca30265SArnd Bergmann attrs.ia_atime = (struct hostfs_timespec) 829bca30265SArnd Bergmann { attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec }; 8301da177e4SLinus Torvalds } 8311da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8321da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 833bca30265SArnd Bergmann attrs.ia_mtime = (struct hostfs_timespec) 834bca30265SArnd Bergmann { attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec }; 8351da177e4SLinus Torvalds } 8361da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8371da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 838bca30265SArnd Bergmann attrs.ia_ctime = (struct hostfs_timespec) 839bca30265SArnd Bergmann { attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec }; 8401da177e4SLinus Torvalds } 8411da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8421da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8431da177e4SLinus Torvalds } 8441da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8451da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8461da177e4SLinus Torvalds } 847c5322220SAl Viro name = dentry_name(dentry); 848f1adc05eSJeff Dike if (name == NULL) 849f1adc05eSJeff Dike return -ENOMEM; 8505822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 851e9193059SAl Viro __putname(name); 8521da177e4SLinus Torvalds if (err) 853f1adc05eSJeff Dike return err; 8541da177e4SLinus Torvalds 8551025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 856bc077320SMarco Stornelli attr->ia_size != i_size_read(inode)) 8573be2be0aSMarco Stornelli truncate_setsize(inode, attr->ia_size); 8581025774cSChristoph Hellwig 8592f221d6fSChristian Brauner setattr_copy(&init_user_ns, inode, attr); 8601025774cSChristoph Hellwig mark_inode_dirty(inode); 8611025774cSChristoph Hellwig return 0; 8621da177e4SLinus Torvalds } 8631da177e4SLinus Torvalds 86492e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8651da177e4SLinus Torvalds .permission = hostfs_permission, 8661da177e4SLinus Torvalds .setattr = hostfs_setattr, 8671da177e4SLinus Torvalds }; 8681da177e4SLinus Torvalds 86992e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8701da177e4SLinus Torvalds .create = hostfs_create, 8711da177e4SLinus Torvalds .lookup = hostfs_lookup, 8721da177e4SLinus Torvalds .link = hostfs_link, 8731da177e4SLinus Torvalds .unlink = hostfs_unlink, 8741da177e4SLinus Torvalds .symlink = hostfs_symlink, 8751da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8761da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8771da177e4SLinus Torvalds .mknod = hostfs_mknod, 8782773bf00SMiklos Szeredi .rename = hostfs_rename2, 8791da177e4SLinus Torvalds .permission = hostfs_permission, 8801da177e4SLinus Torvalds .setattr = hostfs_setattr, 8811da177e4SLinus Torvalds }; 8821da177e4SLinus Torvalds 8836b255391SAl Viro static const char *hostfs_get_link(struct dentry *dentry, 884fceef393SAl Viro struct inode *inode, 885fceef393SAl Viro struct delayed_call *done) 8861da177e4SLinus Torvalds { 8876b255391SAl Viro char *link; 8886b255391SAl Viro if (!dentry) 8896b255391SAl Viro return ERR_PTR(-ECHILD); 890fceef393SAl Viro link = kmalloc(PATH_MAX, GFP_KERNEL); 891d0352d3eSAl Viro if (link) { 892d0352d3eSAl Viro char *path = dentry_name(dentry); 893d0352d3eSAl Viro int err = -ENOMEM; 894d0352d3eSAl Viro if (path) { 8953b6036d1SAl Viro err = hostfs_do_readlink(path, link, PATH_MAX); 896d0352d3eSAl Viro if (err == PATH_MAX) 8971da177e4SLinus Torvalds err = -E2BIG; 898e9193059SAl Viro __putname(path); 8991da177e4SLinus Torvalds } 900d0352d3eSAl Viro if (err < 0) { 901fceef393SAl Viro kfree(link); 902680baacbSAl Viro return ERR_PTR(err); 903d0352d3eSAl Viro } 904d0352d3eSAl Viro } else { 905680baacbSAl Viro return ERR_PTR(-ENOMEM); 9061da177e4SLinus Torvalds } 9071da177e4SLinus Torvalds 908fceef393SAl Viro set_delayed_call(done, kfree_link, link); 909fceef393SAl Viro return link; 910d0352d3eSAl Viro } 911d0352d3eSAl Viro 912d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 9136b255391SAl Viro .get_link = hostfs_get_link, 9141da177e4SLinus Torvalds }; 9151da177e4SLinus Torvalds 9161da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9171da177e4SLinus Torvalds { 9181da177e4SLinus Torvalds struct inode *root_inode; 91975e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9201da177e4SLinus Torvalds int err; 9211da177e4SLinus Torvalds 9221da177e4SLinus Torvalds sb->s_blocksize = 1024; 9231da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9241da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9251da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 926b26d4cd3SAl Viro sb->s_d_op = &simple_dentry_operations; 927752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 928ce72750fSSjoerd Simons err = super_setup_bdi(sb); 929ce72750fSSjoerd Simons if (err) 930ce72750fSSjoerd Simons goto out; 9311da177e4SLinus Torvalds 932b58c4e96SAndy Shevchenko /* NULL is printed as '(null)' by printf(): avoid that. */ 93375e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 93475e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds err = -ENOMEM; 937601d2c38SAl Viro sb->s_fs_info = host_root_path = 938b58c4e96SAndy Shevchenko kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root); 93975e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9401da177e4SLinus Torvalds goto out; 9411da177e4SLinus Torvalds 94252b209f7SAl Viro root_inode = new_inode(sb); 94352b209f7SAl Viro if (!root_inode) 944601d2c38SAl Viro goto out; 9451da177e4SLinus Torvalds 9464754b825SAl Viro err = read_name(root_inode, host_root_path); 9474754b825SAl Viro if (err) 9484754b825SAl Viro goto out_put; 94952b209f7SAl Viro 9504754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 95152b209f7SAl Viro char *name = follow_link(host_root_path); 9528a545f18SDan Carpenter if (IS_ERR(name)) { 95352b209f7SAl Viro err = PTR_ERR(name); 9548a545f18SDan Carpenter goto out_put; 9558a545f18SDan Carpenter } 95652b209f7SAl Viro err = read_name(root_inode, name); 95752b209f7SAl Viro kfree(name); 9581da177e4SLinus Torvalds if (err) 9591da177e4SLinus Torvalds goto out_put; 9604754b825SAl Viro } 9611da177e4SLinus Torvalds 9621da177e4SLinus Torvalds err = -ENOMEM; 96348fde701SAl Viro sb->s_root = d_make_root(root_inode); 9641da177e4SLinus Torvalds if (sb->s_root == NULL) 96548fde701SAl Viro goto out; 9661da177e4SLinus Torvalds 967f1adc05eSJeff Dike return 0; 9681da177e4SLinus Torvalds 9691da177e4SLinus Torvalds out_put: 9701da177e4SLinus Torvalds iput(root_inode); 9711da177e4SLinus Torvalds out: 972f1adc05eSJeff Dike return err; 9731da177e4SLinus Torvalds } 9741da177e4SLinus Torvalds 9753c26ff6eSAl Viro static struct dentry *hostfs_read_sb(struct file_system_type *type, 9761da177e4SLinus Torvalds int flags, const char *dev_name, 9773c26ff6eSAl Viro void *data) 9781da177e4SLinus Torvalds { 9793c26ff6eSAl Viro return mount_nodev(type, flags, data, hostfs_fill_sb_common); 9801da177e4SLinus Torvalds } 9811da177e4SLinus Torvalds 982601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 983601d2c38SAl Viro { 984601d2c38SAl Viro kill_anon_super(s); 985601d2c38SAl Viro kfree(s->s_fs_info); 986601d2c38SAl Viro } 987601d2c38SAl Viro 9881da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 9891da177e4SLinus Torvalds .owner = THIS_MODULE, 9901da177e4SLinus Torvalds .name = "hostfs", 9913c26ff6eSAl Viro .mount = hostfs_read_sb, 992601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 9931da177e4SLinus Torvalds .fs_flags = 0, 9941da177e4SLinus Torvalds }; 9953e64fe5bSEric W. Biederman MODULE_ALIAS_FS("hostfs"); 9961da177e4SLinus Torvalds 9971da177e4SLinus Torvalds static int __init init_hostfs(void) 9981da177e4SLinus Torvalds { 999a15f1e41SJohannes Berg hostfs_inode_cache = KMEM_CACHE(hostfs_inode_info, 0); 1000a15f1e41SJohannes Berg if (!hostfs_inode_cache) 1001a15f1e41SJohannes Berg return -ENOMEM; 1002f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 10031da177e4SLinus Torvalds } 10041da177e4SLinus Torvalds 10051da177e4SLinus Torvalds static void __exit exit_hostfs(void) 10061da177e4SLinus Torvalds { 10071da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 1008a15f1e41SJohannes Berg kmem_cache_destroy(hostfs_inode_cache); 10091da177e4SLinus Torvalds } 10101da177e4SLinus Torvalds 10111da177e4SLinus Torvalds module_init(init_hostfs) 10121da177e4SLinus Torvalds module_exit(exit_hostfs) 10131da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1014