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 } 96aad50b1eSRichard Weinberger 97aad50b1eSRichard Weinberger /* 98aad50b1eSRichard Weinberger * This function relies on the fact that dentry_path_raw() will place 99aad50b1eSRichard Weinberger * the path name at the end of the provided buffer. 100aad50b1eSRichard Weinberger */ 101aad50b1eSRichard Weinberger BUG_ON(p + strlen(p) + 1 != name + PATH_MAX); 102aad50b1eSRichard Weinberger 103850a496fSAl Viro strlcpy(name, root, PATH_MAX); 104e9193059SAl Viro if (len > p - name) { 105e9193059SAl Viro __putname(name); 106e9193059SAl Viro return NULL; 107e9193059SAl Viro } 108e9193059SAl Viro if (p > name + len) { 109e9193059SAl Viro char *s = name + len; 110e9193059SAl Viro while ((*s++ = *p++) != '\0') 111e9193059SAl Viro ; 112e9193059SAl Viro } 113e9193059SAl Viro return name; 114e9193059SAl Viro } 115e9193059SAl Viro 116c5322220SAl Viro static char *dentry_name(struct dentry *dentry) 1171da177e4SLinus Torvalds { 118e9193059SAl Viro char *name = __getname(); 119e9193059SAl Viro if (!name) 120f1adc05eSJeff Dike return NULL; 1211da177e4SLinus Torvalds 1229dcc5e8aSJames Hogan return __dentry_name(dentry, name); 1231da177e4SLinus Torvalds } 1241da177e4SLinus Torvalds 125c5322220SAl Viro static char *inode_name(struct inode *ino) 1261da177e4SLinus Torvalds { 1271da177e4SLinus Torvalds struct dentry *dentry; 128ec2447c2SNick Piggin char *name; 129ec2447c2SNick Piggin 130ec2447c2SNick Piggin dentry = d_find_alias(ino); 131ec2447c2SNick Piggin if (!dentry) 132e9193059SAl Viro return NULL; 1331da177e4SLinus Torvalds 134ec2447c2SNick Piggin name = dentry_name(dentry); 135ec2447c2SNick Piggin 136ec2447c2SNick Piggin dput(dentry); 137ec2447c2SNick Piggin 138ec2447c2SNick Piggin return name; 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds 1411da177e4SLinus Torvalds static char *follow_link(char *link) 1421da177e4SLinus Torvalds { 1431da177e4SLinus Torvalds int len, n; 1441da177e4SLinus Torvalds char *name, *resolved, *end; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds len = 64; 1471da177e4SLinus Torvalds while (1) { 1481da177e4SLinus Torvalds n = -ENOMEM; 1491da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1501da177e4SLinus Torvalds if (name == NULL) 1511da177e4SLinus Torvalds goto out; 1521da177e4SLinus Torvalds 153ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1541da177e4SLinus Torvalds if (n < len) 1551da177e4SLinus Torvalds break; 1561da177e4SLinus Torvalds len *= 2; 1571da177e4SLinus Torvalds kfree(name); 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds if (n < 0) 1601da177e4SLinus Torvalds goto out_free; 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 len = strlen(link) + strlen(name) + 1; 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1731da177e4SLinus Torvalds if (resolved == NULL) { 1741da177e4SLinus Torvalds n = -ENOMEM; 1751da177e4SLinus Torvalds goto out_free; 1761da177e4SLinus Torvalds } 1771da177e4SLinus Torvalds 1781da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1791da177e4SLinus Torvalds kfree(name); 1801da177e4SLinus Torvalds kfree(link); 181f1adc05eSJeff Dike return resolved; 1821da177e4SLinus Torvalds 1831da177e4SLinus Torvalds out_free: 1841da177e4SLinus Torvalds kfree(name); 1851da177e4SLinus Torvalds out: 186f1adc05eSJeff Dike return ERR_PTR(n); 1871da177e4SLinus Torvalds } 1881da177e4SLinus Torvalds 1890a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1900a370e5dSDavid Howells { 19152b209f7SAl Viro struct inode *inode = new_inode(sb); 1920a370e5dSDavid Howells if (!inode) 1930a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 1940a370e5dSDavid Howells return inode; 1950a370e5dSDavid Howells } 1960a370e5dSDavid Howells 1979e443bc3SJames Hogan static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 1981da177e4SLinus Torvalds { 19984b3db04SJeff Dike /* 20084b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 2011da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 2021da177e4SLinus Torvalds * so we convert them here 2031da177e4SLinus Torvalds */ 2041da177e4SLinus Torvalds int err; 2051da177e4SLinus Torvalds long long f_blocks; 2061da177e4SLinus Torvalds long long f_bfree; 2071da177e4SLinus Torvalds long long f_bavail; 2081da177e4SLinus Torvalds long long f_files; 2091da177e4SLinus Torvalds long long f_ffree; 2101da177e4SLinus Torvalds 211601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2121da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2131da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2141b627d57SRichard Weinberger &sf->f_namelen); 215f1adc05eSJeff Dike if (err) 216f1adc05eSJeff Dike return err; 2171da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2181da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2191da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2201da177e4SLinus Torvalds sf->f_files = f_files; 2211da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2221da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 223f1adc05eSJeff Dike return 0; 2241da177e4SLinus Torvalds } 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2271da177e4SLinus Torvalds { 2281da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2291da177e4SLinus Torvalds 230371fdab1SJames Hogan hi = kmalloc(sizeof(*hi), GFP_KERNEL); 2311da177e4SLinus Torvalds if (hi == NULL) 232f1adc05eSJeff Dike return NULL; 233601d2c38SAl Viro hi->fd = -1; 234371fdab1SJames Hogan hi->mode = 0; 2351da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 23669886e67SRichard Weinberger mutex_init(&hi->open_mutex); 237f1adc05eSJeff Dike return &hi->vfs_inode; 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 240e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2411da177e4SLinus Torvalds { 24291b0abe3SJohannes Weiner truncate_inode_pages_final(&inode->i_data); 243dbd5768fSJan Kara clear_inode(inode); 2441da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 2451da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 2461da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds 250fa0d7e3dSNick Piggin static void hostfs_i_callback(struct rcu_head *head) 251fa0d7e3dSNick Piggin { 252fa0d7e3dSNick Piggin struct inode *inode = container_of(head, struct inode, i_rcu); 253fa0d7e3dSNick Piggin kfree(HOSTFS_I(inode)); 254fa0d7e3dSNick Piggin } 255fa0d7e3dSNick Piggin 2561da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 2571da177e4SLinus Torvalds { 258fa0d7e3dSNick Piggin call_rcu(&inode->i_rcu, hostfs_i_callback); 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 26134c80b1dSAl Viro static int hostfs_show_options(struct seq_file *seq, struct dentry *root) 262dd2cc4dfSMiklos Szeredi { 26334c80b1dSAl Viro const char *root_path = root->d_sb->s_fs_info; 264dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 265dd2cc4dfSMiklos Szeredi 266dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 267dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 268dd2cc4dfSMiklos Szeredi 269dd2cc4dfSMiklos Szeredi return 0; 270dd2cc4dfSMiklos Szeredi } 271dd2cc4dfSMiklos Szeredi 272ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 2731da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 2741da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 275e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 2761da177e4SLinus Torvalds .statfs = hostfs_statfs, 277dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 2781da177e4SLinus Torvalds }; 2791da177e4SLinus Torvalds 2809e443bc3SJames Hogan static int hostfs_readdir(struct file *file, struct dir_context *ctx) 2811da177e4SLinus Torvalds { 2821da177e4SLinus Torvalds void *dir; 2831da177e4SLinus Torvalds char *name; 2841da177e4SLinus Torvalds unsigned long long next, ino; 2851da177e4SLinus Torvalds int error, len; 2863ee6bd8eSGeert Uytterhoeven unsigned int type; 2871da177e4SLinus Torvalds 288c5322220SAl Viro name = dentry_name(file->f_path.dentry); 289f1adc05eSJeff Dike if (name == NULL) 290f1adc05eSJeff Dike return -ENOMEM; 2911da177e4SLinus Torvalds dir = open_dir(name, &error); 292e9193059SAl Viro __putname(name); 293f1adc05eSJeff Dike if (dir == NULL) 294f1adc05eSJeff Dike return -error; 2958e28bc7eSAl Viro next = ctx->pos; 2963ee6bd8eSGeert Uytterhoeven while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) { 2978e28bc7eSAl Viro if (!dir_emit(ctx, name, len, ino, type)) 2988e28bc7eSAl Viro break; 2998e28bc7eSAl Viro ctx->pos = next; 3001da177e4SLinus Torvalds } 3011da177e4SLinus Torvalds close_dir(dir); 302f1adc05eSJeff Dike return 0; 3031da177e4SLinus Torvalds } 3041da177e4SLinus Torvalds 3054c6dcafcSRichard Weinberger static int hostfs_open(struct inode *ino, struct file *file) 3061da177e4SLinus Torvalds { 3071da177e4SLinus Torvalds char *name; 308aeb5d727SAl Viro fmode_t mode = 0; 309f8ad850fSAl Viro int err; 310aeb5d727SAl Viro int r = 0, w = 0, fd; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3131da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 314f1adc05eSJeff Dike return 0; 3151da177e4SLinus Torvalds 316f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 3171da177e4SLinus Torvalds 318f8ad850fSAl Viro retry: 319f8ad850fSAl Viro if (mode & FMODE_READ) 3201da177e4SLinus Torvalds r = 1; 321f8ad850fSAl Viro if (mode & FMODE_WRITE) 3221da177e4SLinus Torvalds w = 1; 3231da177e4SLinus Torvalds if (w) 3241da177e4SLinus Torvalds r = 1; 3251da177e4SLinus Torvalds 326c5322220SAl Viro name = dentry_name(file->f_path.dentry); 3271da177e4SLinus Torvalds if (name == NULL) 328f1adc05eSJeff Dike return -ENOMEM; 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds fd = open_file(name, r, w, append); 331e9193059SAl Viro __putname(name); 332f1adc05eSJeff Dike if (fd < 0) 333f1adc05eSJeff Dike return fd; 334f8ad850fSAl Viro 33569886e67SRichard Weinberger mutex_lock(&HOSTFS_I(ino)->open_mutex); 336f8ad850fSAl Viro /* somebody else had handled it first? */ 337f8ad850fSAl Viro if ((mode & HOSTFS_I(ino)->mode) == mode) { 33869886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 339af955658SRichard Weinberger close_file(&fd); 340f8ad850fSAl Viro return 0; 341f8ad850fSAl Viro } 342f8ad850fSAl Viro if ((mode | HOSTFS_I(ino)->mode) != mode) { 343f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 34469886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 345f8ad850fSAl Viro close_file(&fd); 346f8ad850fSAl Viro goto retry; 347f8ad850fSAl Viro } 348f8ad850fSAl Viro if (HOSTFS_I(ino)->fd == -1) { 349f8ad850fSAl Viro HOSTFS_I(ino)->fd = fd; 350f8ad850fSAl Viro } else { 351f8ad850fSAl Viro err = replace_file(fd, HOSTFS_I(ino)->fd); 352f8ad850fSAl Viro close_file(&fd); 353f8ad850fSAl Viro if (err < 0) { 35469886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 355f8ad850fSAl Viro return err; 356f8ad850fSAl Viro } 357f8ad850fSAl Viro } 358f8ad850fSAl Viro HOSTFS_I(ino)->mode = mode; 35969886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex); 3601da177e4SLinus Torvalds 361f1adc05eSJeff Dike return 0; 3621da177e4SLinus Torvalds } 3631da177e4SLinus Torvalds 36465984ff9SRichard Weinberger static int hostfs_file_release(struct inode *inode, struct file *file) 36565984ff9SRichard Weinberger { 36665984ff9SRichard Weinberger filemap_write_and_wait(inode->i_mapping); 36765984ff9SRichard Weinberger 36865984ff9SRichard Weinberger return 0; 36965984ff9SRichard Weinberger } 37065984ff9SRichard Weinberger 3719e443bc3SJames Hogan static int hostfs_fsync(struct file *file, loff_t start, loff_t end, 3729e443bc3SJames Hogan int datasync) 3731da177e4SLinus Torvalds { 37402c24a82SJosef Bacik struct inode *inode = file->f_mapping->host; 37502c24a82SJosef Bacik int ret; 37602c24a82SJosef Bacik 37702c24a82SJosef Bacik ret = filemap_write_and_wait_range(inode->i_mapping, start, end); 37802c24a82SJosef Bacik if (ret) 37902c24a82SJosef Bacik return ret; 38002c24a82SJosef Bacik 38102c24a82SJosef Bacik mutex_lock(&inode->i_mutex); 38202c24a82SJosef Bacik ret = fsync_file(HOSTFS_I(inode)->fd, datasync); 38302c24a82SJosef Bacik mutex_unlock(&inode->i_mutex); 38402c24a82SJosef Bacik 38502c24a82SJosef Bacik return ret; 3861da177e4SLinus Torvalds } 3871da177e4SLinus Torvalds 3884b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3891da177e4SLinus Torvalds .llseek = generic_file_llseek, 390aad4f8bbSAl Viro .read = new_sync_read, 3915ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 392aad4f8bbSAl Viro .read_iter = generic_file_read_iter, 3938174202bSAl Viro .write_iter = generic_file_write_iter, 3948174202bSAl Viro .write = new_sync_write, 3951da177e4SLinus Torvalds .mmap = generic_file_mmap, 3964c6dcafcSRichard Weinberger .open = hostfs_open, 39765984ff9SRichard Weinberger .release = hostfs_file_release, 3981da177e4SLinus Torvalds .fsync = hostfs_fsync, 3991da177e4SLinus Torvalds }; 4001da177e4SLinus Torvalds 4014b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 4021da177e4SLinus Torvalds .llseek = generic_file_llseek, 4038e28bc7eSAl Viro .iterate = hostfs_readdir, 4041da177e4SLinus Torvalds .read = generic_read_dir, 4054c6dcafcSRichard Weinberger .open = hostfs_open, 4064c6dcafcSRichard Weinberger .fsync = hostfs_fsync, 4071da177e4SLinus Torvalds }; 4081da177e4SLinus Torvalds 4099e443bc3SJames Hogan static int hostfs_writepage(struct page *page, struct writeback_control *wbc) 4101da177e4SLinus Torvalds { 4111da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 4121da177e4SLinus Torvalds struct inode *inode = mapping->host; 4131da177e4SLinus Torvalds char *buffer; 4141da177e4SLinus Torvalds unsigned long long base; 4151da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 4161da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 4171da177e4SLinus Torvalds int err; 4181da177e4SLinus Torvalds 4191da177e4SLinus Torvalds if (page->index >= end_index) 4201da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 4211da177e4SLinus Torvalds 4221da177e4SLinus Torvalds buffer = kmap(page); 4231da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4261da177e4SLinus Torvalds if (err != count) { 4271da177e4SLinus Torvalds ClearPageUptodate(page); 4281da177e4SLinus Torvalds goto out; 4291da177e4SLinus Torvalds } 4301da177e4SLinus Torvalds 4311da177e4SLinus Torvalds if (base > inode->i_size) 4321da177e4SLinus Torvalds inode->i_size = base; 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds if (PageError(page)) 4351da177e4SLinus Torvalds ClearPageError(page); 4361da177e4SLinus Torvalds err = 0; 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds out: 4391da177e4SLinus Torvalds kunmap(page); 4401da177e4SLinus Torvalds 4411da177e4SLinus Torvalds unlock_page(page); 4421da177e4SLinus Torvalds return err; 4431da177e4SLinus Torvalds } 4441da177e4SLinus Torvalds 4459e443bc3SJames Hogan static int hostfs_readpage(struct file *file, struct page *page) 4461da177e4SLinus Torvalds { 4471da177e4SLinus Torvalds char *buffer; 4481da177e4SLinus Torvalds long long start; 44941761ddfSRichard Weinberger int bytes_read, ret; 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4521da177e4SLinus Torvalds buffer = kmap(page); 45341761ddfSRichard Weinberger bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4541da177e4SLinus Torvalds PAGE_CACHE_SIZE); 45541761ddfSRichard Weinberger if (bytes_read < 0) { 45641761ddfSRichard Weinberger ret = bytes_read; 45784b3db04SJeff Dike goto out; 45841761ddfSRichard Weinberger } 4591da177e4SLinus Torvalds 46041761ddfSRichard Weinberger memset(buffer + bytes_read, 0, PAGE_CACHE_SIZE - bytes_read); 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds flush_dcache_page(page); 4631da177e4SLinus Torvalds SetPageUptodate(page); 4641da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 46541761ddfSRichard Weinberger ret = 0; 4661da177e4SLinus Torvalds out: 4671da177e4SLinus Torvalds kunmap(page); 4681da177e4SLinus Torvalds unlock_page(page); 46941761ddfSRichard Weinberger return ret; 4701da177e4SLinus Torvalds } 4711da177e4SLinus Torvalds 4729e443bc3SJames Hogan static int hostfs_write_begin(struct file *file, struct address_space *mapping, 473ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 474ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4751da177e4SLinus Torvalds { 476ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 477ae361ff4SNick Piggin 47854566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 479ae361ff4SNick Piggin if (!*pagep) 480ae361ff4SNick Piggin return -ENOMEM; 481ae361ff4SNick Piggin return 0; 482ae361ff4SNick Piggin } 483ae361ff4SNick Piggin 4849e443bc3SJames Hogan static int hostfs_write_end(struct file *file, struct address_space *mapping, 485ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 486ae361ff4SNick Piggin struct page *page, void *fsdata) 487ae361ff4SNick Piggin { 488ae361ff4SNick Piggin struct inode *inode = mapping->host; 489ae361ff4SNick Piggin void *buffer; 490ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 4911da177e4SLinus Torvalds int err; 4921da177e4SLinus Torvalds 4931da177e4SLinus Torvalds buffer = kmap(page); 494ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 4951da177e4SLinus Torvalds kunmap(page); 4961da177e4SLinus Torvalds 497ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 498ae361ff4SNick Piggin SetPageUptodate(page); 4991da177e4SLinus Torvalds 50084b3db04SJeff Dike /* 50184b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 502ae361ff4SNick Piggin * i_size against the last byte written. 503ae361ff4SNick Piggin */ 504ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 505ae361ff4SNick Piggin inode->i_size = pos; 506ae361ff4SNick Piggin unlock_page(page); 507ae361ff4SNick Piggin page_cache_release(page); 50830f04a4eSPaolo 'Blaisorblade' Giarrusso 509f1adc05eSJeff Dike return err; 5101da177e4SLinus Torvalds } 5111da177e4SLinus Torvalds 512f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 5131da177e4SLinus Torvalds .writepage = hostfs_writepage, 5141da177e4SLinus Torvalds .readpage = hostfs_readpage, 515ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 516ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 517ae361ff4SNick Piggin .write_end = hostfs_write_end, 5181da177e4SLinus Torvalds }; 5191da177e4SLinus Torvalds 5204754b825SAl Viro static int read_name(struct inode *ino, char *name) 5211da177e4SLinus Torvalds { 5224754b825SAl Viro dev_t rdev; 5234754b825SAl Viro struct hostfs_stat st; 5244754b825SAl Viro int err = stat_file(name, &st, -1); 5254754b825SAl Viro if (err) 5264754b825SAl Viro return err; 5271da177e4SLinus Torvalds 5281da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 5294754b825SAl Viro rdev = MKDEV(st.maj, st.min); 5301da177e4SLinus Torvalds 5314754b825SAl Viro switch (st.mode & S_IFMT) { 5324754b825SAl Viro case S_IFLNK: 533d0352d3eSAl Viro ino->i_op = &hostfs_link_iops; 5344754b825SAl Viro break; 5354754b825SAl Viro case S_IFDIR: 5364754b825SAl Viro ino->i_op = &hostfs_dir_iops; 5374754b825SAl Viro ino->i_fop = &hostfs_dir_fops; 5384754b825SAl Viro break; 5394754b825SAl Viro case S_IFCHR: 5404754b825SAl Viro case S_IFBLK: 5414754b825SAl Viro case S_IFIFO: 5424754b825SAl Viro case S_IFSOCK: 5434754b825SAl Viro init_special_inode(ino, st.mode & S_IFMT, rdev); 5444754b825SAl Viro ino->i_op = &hostfs_iops; 5454754b825SAl Viro break; 5462ad2dca6SRichard Weinberger case S_IFREG: 5474754b825SAl Viro ino->i_op = &hostfs_iops; 5484754b825SAl Viro ino->i_fop = &hostfs_file_fops; 5494754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops; 5502ad2dca6SRichard Weinberger break; 5512ad2dca6SRichard Weinberger default: 5522ad2dca6SRichard Weinberger return -EIO; 5531da177e4SLinus Torvalds } 5544754b825SAl Viro 5554754b825SAl Viro ino->i_ino = st.ino; 5564754b825SAl Viro ino->i_mode = st.mode; 557bfe86848SMiklos Szeredi set_nlink(ino, st.nlink); 55829f82ae5SEric W. Biederman i_uid_write(ino, st.uid); 55929f82ae5SEric W. Biederman i_gid_write(ino, st.gid); 5604754b825SAl Viro ino->i_atime = st.atime; 5614754b825SAl Viro ino->i_mtime = st.mtime; 5624754b825SAl Viro ino->i_ctime = st.ctime; 5634754b825SAl Viro ino->i_size = st.size; 5644754b825SAl Viro ino->i_blocks = st.blocks; 5654754b825SAl Viro return 0; 5661da177e4SLinus Torvalds } 5671da177e4SLinus Torvalds 5689e443bc3SJames Hogan static int hostfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 569ebfc3b49SAl Viro bool excl) 5701da177e4SLinus Torvalds { 5711da177e4SLinus Torvalds struct inode *inode; 5721da177e4SLinus Torvalds char *name; 5731da177e4SLinus Torvalds int error, fd; 5741da177e4SLinus Torvalds 5750a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5760a370e5dSDavid Howells if (IS_ERR(inode)) { 5770a370e5dSDavid Howells error = PTR_ERR(inode); 57884b3db04SJeff Dike goto out; 5790a370e5dSDavid Howells } 5801da177e4SLinus Torvalds 5811da177e4SLinus Torvalds error = -ENOMEM; 582c5322220SAl Viro name = dentry_name(dentry); 5831da177e4SLinus Torvalds if (name == NULL) 5841da177e4SLinus Torvalds goto out_put; 5851da177e4SLinus Torvalds 5861da177e4SLinus Torvalds fd = file_create(name, 5871da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 5881da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 5891da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 5904754b825SAl Viro if (fd < 0) 5911da177e4SLinus Torvalds error = fd; 5924754b825SAl Viro else 5935e2df28cSAl Viro error = read_name(inode, name); 5941da177e4SLinus Torvalds 595e9193059SAl Viro __putname(name); 5961da177e4SLinus Torvalds if (error) 5971da177e4SLinus Torvalds goto out_put; 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 6001da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 6011da177e4SLinus Torvalds d_instantiate(dentry, inode); 602f1adc05eSJeff Dike return 0; 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds out_put: 6051da177e4SLinus Torvalds iput(inode); 6061da177e4SLinus Torvalds out: 607f1adc05eSJeff Dike return error; 6081da177e4SLinus Torvalds } 6091da177e4SLinus Torvalds 6109e443bc3SJames Hogan static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 61100cd8dd3SAl Viro unsigned int flags) 6121da177e4SLinus Torvalds { 6131da177e4SLinus Torvalds struct inode *inode; 6141da177e4SLinus Torvalds char *name; 6151da177e4SLinus Torvalds int err; 6161da177e4SLinus Torvalds 6170a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 6180a370e5dSDavid Howells if (IS_ERR(inode)) { 6190a370e5dSDavid Howells err = PTR_ERR(inode); 6201da177e4SLinus Torvalds goto out; 6210a370e5dSDavid Howells } 6221da177e4SLinus Torvalds 6231da177e4SLinus Torvalds err = -ENOMEM; 624c5322220SAl Viro name = dentry_name(dentry); 6251da177e4SLinus Torvalds if (name == NULL) 6261da177e4SLinus Torvalds goto out_put; 6271da177e4SLinus Torvalds 6281da177e4SLinus Torvalds err = read_name(inode, name); 6295e2df28cSAl Viro 630e9193059SAl Viro __putname(name); 6311da177e4SLinus Torvalds if (err == -ENOENT) { 6321da177e4SLinus Torvalds iput(inode); 6331da177e4SLinus Torvalds inode = NULL; 6341da177e4SLinus Torvalds } 6351da177e4SLinus Torvalds else if (err) 6361da177e4SLinus Torvalds goto out_put; 6371da177e4SLinus Torvalds 6381da177e4SLinus Torvalds d_add(dentry, inode); 639f1adc05eSJeff Dike return NULL; 6401da177e4SLinus Torvalds 6411da177e4SLinus Torvalds out_put: 6421da177e4SLinus Torvalds iput(inode); 6431da177e4SLinus Torvalds out: 644f1adc05eSJeff Dike return ERR_PTR(err); 6451da177e4SLinus Torvalds } 6461da177e4SLinus Torvalds 6479e443bc3SJames Hogan static int hostfs_link(struct dentry *to, struct inode *ino, 6489e443bc3SJames Hogan struct dentry *from) 6491da177e4SLinus Torvalds { 6501da177e4SLinus Torvalds char *from_name, *to_name; 6511da177e4SLinus Torvalds int err; 6521da177e4SLinus Torvalds 653c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 654f1adc05eSJeff Dike return -ENOMEM; 655c5322220SAl Viro to_name = dentry_name(to); 6561da177e4SLinus Torvalds if (to_name == NULL) { 657e9193059SAl Viro __putname(from_name); 658f1adc05eSJeff Dike return -ENOMEM; 6591da177e4SLinus Torvalds } 6601da177e4SLinus Torvalds err = link_file(to_name, from_name); 661e9193059SAl Viro __putname(from_name); 662e9193059SAl Viro __putname(to_name); 663f1adc05eSJeff Dike return err; 6641da177e4SLinus Torvalds } 6651da177e4SLinus Torvalds 6669e443bc3SJames Hogan static int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6671da177e4SLinus Torvalds { 6681da177e4SLinus Torvalds char *file; 6691da177e4SLinus Torvalds int err; 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds if (append) 672f1adc05eSJeff Dike return -EPERM; 6731da177e4SLinus Torvalds 674f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL) 675f8d7e187SAl Viro return -ENOMEM; 676f8d7e187SAl Viro 6771da177e4SLinus Torvalds err = unlink_file(file); 678e9193059SAl Viro __putname(file); 679f1adc05eSJeff Dike return err; 6801da177e4SLinus Torvalds } 6811da177e4SLinus Torvalds 6829e443bc3SJames Hogan static int hostfs_symlink(struct inode *ino, struct dentry *dentry, 6839e443bc3SJames Hogan const char *to) 6841da177e4SLinus Torvalds { 6851da177e4SLinus Torvalds char *file; 6861da177e4SLinus Torvalds int err; 6871da177e4SLinus Torvalds 688c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 689f1adc05eSJeff Dike return -ENOMEM; 6901da177e4SLinus Torvalds err = make_symlink(file, to); 691e9193059SAl Viro __putname(file); 692f1adc05eSJeff Dike return err; 6931da177e4SLinus Torvalds } 6941da177e4SLinus Torvalds 6959e443bc3SJames Hogan static int hostfs_mkdir(struct inode *ino, struct dentry *dentry, umode_t mode) 6961da177e4SLinus Torvalds { 6971da177e4SLinus Torvalds char *file; 6981da177e4SLinus Torvalds int err; 6991da177e4SLinus Torvalds 700c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 701f1adc05eSJeff Dike return -ENOMEM; 7021da177e4SLinus Torvalds err = do_mkdir(file, mode); 703e9193059SAl Viro __putname(file); 704f1adc05eSJeff Dike return err; 7051da177e4SLinus Torvalds } 7061da177e4SLinus Torvalds 7079e443bc3SJames Hogan static int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 7081da177e4SLinus Torvalds { 7091da177e4SLinus Torvalds char *file; 7101da177e4SLinus Torvalds int err; 7111da177e4SLinus Torvalds 712c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 713f1adc05eSJeff Dike return -ENOMEM; 7141da177e4SLinus Torvalds err = do_rmdir(file); 715e9193059SAl Viro __putname(file); 716f1adc05eSJeff Dike return err; 7171da177e4SLinus Torvalds } 7181da177e4SLinus Torvalds 7191a67aafbSAl Viro static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) 7201da177e4SLinus Torvalds { 7211da177e4SLinus Torvalds struct inode *inode; 7221da177e4SLinus Torvalds char *name; 7230a370e5dSDavid Howells int err; 7241da177e4SLinus Torvalds 7250a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7260a370e5dSDavid Howells if (IS_ERR(inode)) { 7270a370e5dSDavid Howells err = PTR_ERR(inode); 7281da177e4SLinus Torvalds goto out; 7290a370e5dSDavid Howells } 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds err = -ENOMEM; 732c5322220SAl Viro name = dentry_name(dentry); 7331da177e4SLinus Torvalds if (name == NULL) 7341da177e4SLinus Torvalds goto out_put; 7351da177e4SLinus Torvalds 7361da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 73788f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 738e9193059SAl Viro if (!err) 7391da177e4SLinus Torvalds goto out_free; 7401da177e4SLinus Torvalds 7411da177e4SLinus Torvalds err = read_name(inode, name); 742e9193059SAl Viro __putname(name); 7435e2df28cSAl Viro if (err) 7445e2df28cSAl Viro goto out_put; 7451da177e4SLinus Torvalds if (err) 7461da177e4SLinus Torvalds goto out_put; 7471da177e4SLinus Torvalds 7481da177e4SLinus Torvalds d_instantiate(dentry, inode); 749f1adc05eSJeff Dike return 0; 7501da177e4SLinus Torvalds 7511da177e4SLinus Torvalds out_free: 752e9193059SAl Viro __putname(name); 7531da177e4SLinus Torvalds out_put: 7541da177e4SLinus Torvalds iput(inode); 7551da177e4SLinus Torvalds out: 756f1adc05eSJeff Dike return err; 7571da177e4SLinus Torvalds } 7581da177e4SLinus Torvalds 7599a423bb6SMiklos Szeredi static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry, 7609a423bb6SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry, 7619a423bb6SMiklos Szeredi unsigned int flags) 7621da177e4SLinus Torvalds { 7639a423bb6SMiklos Szeredi char *old_name, *new_name; 7641da177e4SLinus Torvalds int err; 7651da177e4SLinus Torvalds 7669a423bb6SMiklos Szeredi if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 7679a423bb6SMiklos Szeredi return -EINVAL; 7689a423bb6SMiklos Szeredi 7699a423bb6SMiklos Szeredi old_name = dentry_name(old_dentry); 7709a423bb6SMiklos Szeredi if (old_name == NULL) 771f1adc05eSJeff Dike return -ENOMEM; 7729a423bb6SMiklos Szeredi new_name = dentry_name(new_dentry); 7739a423bb6SMiklos Szeredi if (new_name == NULL) { 7749a423bb6SMiklos Szeredi __putname(old_name); 775f1adc05eSJeff Dike return -ENOMEM; 7761da177e4SLinus Torvalds } 7779a423bb6SMiklos Szeredi if (!flags) 7789a423bb6SMiklos Szeredi err = rename_file(old_name, new_name); 7799a423bb6SMiklos Szeredi else 7809a423bb6SMiklos Szeredi err = rename2_file(old_name, new_name, flags); 7819a423bb6SMiklos Szeredi 7829a423bb6SMiklos Szeredi __putname(old_name); 7839a423bb6SMiklos Szeredi __putname(new_name); 784f1adc05eSJeff Dike return err; 7851da177e4SLinus Torvalds } 7861da177e4SLinus Torvalds 7879e443bc3SJames Hogan static int hostfs_permission(struct inode *ino, int desired) 7881da177e4SLinus Torvalds { 7891da177e4SLinus Torvalds char *name; 7901da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7911da177e4SLinus Torvalds 79210556cb2SAl Viro if (desired & MAY_NOT_BLOCK) 793b74c79e9SNick Piggin return -ECHILD; 794b74c79e9SNick Piggin 7951da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7961da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7971da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 798c5322220SAl Viro name = inode_name(ino); 799f1adc05eSJeff Dike if (name == NULL) 800f1adc05eSJeff Dike return -ENOMEM; 8011da177e4SLinus Torvalds 8021da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 8031da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 8041da177e4SLinus Torvalds err = 0; 8051da177e4SLinus Torvalds else 8061da177e4SLinus Torvalds err = access_file(name, r, w, x); 807e9193059SAl Viro __putname(name); 8081da177e4SLinus Torvalds if (!err) 8092830ba7fSAl Viro err = generic_permission(ino, desired); 8101da177e4SLinus Torvalds return err; 8111da177e4SLinus Torvalds } 8121da177e4SLinus Torvalds 8139e443bc3SJames Hogan static int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 8141da177e4SLinus Torvalds { 8151025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 8161da177e4SLinus Torvalds struct hostfs_iattr attrs; 8171da177e4SLinus Torvalds char *name; 8181da177e4SLinus Torvalds int err; 8191da177e4SLinus Torvalds 8201025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 8215822b7faSAlberto Bertogli 8221025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 8231da177e4SLinus Torvalds if (err) 8241da177e4SLinus Torvalds return err; 8251da177e4SLinus Torvalds 8261da177e4SLinus Torvalds if (append) 8271da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 8281da177e4SLinus Torvalds 8291da177e4SLinus Torvalds attrs.ia_valid = 0; 8301da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 8311da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 8321da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 8331da177e4SLinus Torvalds } 8341da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8351da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 83629f82ae5SEric W. Biederman attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid); 8371da177e4SLinus Torvalds } 8381da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8391da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 84029f82ae5SEric W. Biederman attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid); 8411da177e4SLinus Torvalds } 8421da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8431da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8441da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8451da177e4SLinus Torvalds } 8461da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8471da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 8481da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 8491da177e4SLinus Torvalds } 8501da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8511da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 8521da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 8531da177e4SLinus Torvalds } 8541da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8551da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 8561da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 8571da177e4SLinus Torvalds } 8581da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8591da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8601da177e4SLinus Torvalds } 8611da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8621da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8631da177e4SLinus Torvalds } 864c5322220SAl Viro name = dentry_name(dentry); 865f1adc05eSJeff Dike if (name == NULL) 866f1adc05eSJeff Dike return -ENOMEM; 8675822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 868e9193059SAl Viro __putname(name); 8691da177e4SLinus Torvalds if (err) 870f1adc05eSJeff Dike return err; 8711da177e4SLinus Torvalds 8721025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 873bc077320SMarco Stornelli attr->ia_size != i_size_read(inode)) 8743be2be0aSMarco Stornelli truncate_setsize(inode, attr->ia_size); 8751025774cSChristoph Hellwig 8761025774cSChristoph Hellwig setattr_copy(inode, attr); 8771025774cSChristoph Hellwig mark_inode_dirty(inode); 8781025774cSChristoph Hellwig return 0; 8791da177e4SLinus Torvalds } 8801da177e4SLinus Torvalds 88192e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8821da177e4SLinus Torvalds .permission = hostfs_permission, 8831da177e4SLinus Torvalds .setattr = hostfs_setattr, 8841da177e4SLinus Torvalds }; 8851da177e4SLinus Torvalds 88692e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8871da177e4SLinus Torvalds .create = hostfs_create, 8881da177e4SLinus Torvalds .lookup = hostfs_lookup, 8891da177e4SLinus Torvalds .link = hostfs_link, 8901da177e4SLinus Torvalds .unlink = hostfs_unlink, 8911da177e4SLinus Torvalds .symlink = hostfs_symlink, 8921da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8931da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8941da177e4SLinus Torvalds .mknod = hostfs_mknod, 8959a423bb6SMiklos Szeredi .rename2 = hostfs_rename2, 8961da177e4SLinus Torvalds .permission = hostfs_permission, 8971da177e4SLinus Torvalds .setattr = hostfs_setattr, 8981da177e4SLinus Torvalds }; 8991da177e4SLinus Torvalds 900d0352d3eSAl Viro static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) 9011da177e4SLinus Torvalds { 902d0352d3eSAl Viro char *link = __getname(); 903d0352d3eSAl Viro if (link) { 904d0352d3eSAl Viro char *path = dentry_name(dentry); 905d0352d3eSAl Viro int err = -ENOMEM; 906d0352d3eSAl Viro if (path) { 9073b6036d1SAl Viro err = hostfs_do_readlink(path, link, PATH_MAX); 908d0352d3eSAl Viro if (err == PATH_MAX) 9091da177e4SLinus Torvalds err = -E2BIG; 910e9193059SAl Viro __putname(path); 9111da177e4SLinus Torvalds } 912d0352d3eSAl Viro if (err < 0) { 913d0352d3eSAl Viro __putname(link); 914d0352d3eSAl Viro link = ERR_PTR(err); 915d0352d3eSAl Viro } 916d0352d3eSAl Viro } else { 917d0352d3eSAl Viro link = ERR_PTR(-ENOMEM); 9181da177e4SLinus Torvalds } 9191da177e4SLinus Torvalds 920d0352d3eSAl Viro nd_set_link(nd, link); 921d0352d3eSAl Viro return NULL; 922d0352d3eSAl Viro } 923d0352d3eSAl Viro 924d0352d3eSAl Viro static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 925d0352d3eSAl Viro { 926d0352d3eSAl Viro char *s = nd_get_link(nd); 927d0352d3eSAl Viro if (!IS_ERR(s)) 928d0352d3eSAl Viro __putname(s); 929d0352d3eSAl Viro } 930d0352d3eSAl Viro 931d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 932d0352d3eSAl Viro .readlink = generic_readlink, 933d0352d3eSAl Viro .follow_link = hostfs_follow_link, 934d0352d3eSAl Viro .put_link = hostfs_put_link, 9351da177e4SLinus Torvalds }; 9361da177e4SLinus Torvalds 9371da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9381da177e4SLinus Torvalds { 9391da177e4SLinus Torvalds struct inode *root_inode; 94075e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9411da177e4SLinus Torvalds int err; 9421da177e4SLinus Torvalds 9431da177e4SLinus Torvalds sb->s_blocksize = 1024; 9441da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9451da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9461da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 947b26d4cd3SAl Viro sb->s_d_op = &simple_dentry_operations; 948752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9491da177e4SLinus Torvalds 950a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 95175e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 95275e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9531da177e4SLinus Torvalds 9541da177e4SLinus Torvalds err = -ENOMEM; 955601d2c38SAl Viro sb->s_fs_info = host_root_path = 956601d2c38SAl Viro kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); 95775e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9581da177e4SLinus Torvalds goto out; 9591da177e4SLinus Torvalds 96075e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9611da177e4SLinus Torvalds 96252b209f7SAl Viro root_inode = new_inode(sb); 96352b209f7SAl Viro if (!root_inode) 964601d2c38SAl Viro goto out; 9651da177e4SLinus Torvalds 9664754b825SAl Viro err = read_name(root_inode, host_root_path); 9674754b825SAl Viro if (err) 9684754b825SAl Viro goto out_put; 96952b209f7SAl Viro 9704754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 97152b209f7SAl Viro char *name = follow_link(host_root_path); 97252b209f7SAl Viro if (IS_ERR(name)) 97352b209f7SAl Viro err = PTR_ERR(name); 97452b209f7SAl Viro else 97552b209f7SAl Viro err = read_name(root_inode, name); 97652b209f7SAl Viro kfree(name); 9771da177e4SLinus Torvalds if (err) 9781da177e4SLinus Torvalds goto out_put; 9794754b825SAl Viro } 9801da177e4SLinus Torvalds 9811da177e4SLinus Torvalds err = -ENOMEM; 98248fde701SAl Viro sb->s_root = d_make_root(root_inode); 9831da177e4SLinus Torvalds if (sb->s_root == NULL) 98448fde701SAl Viro goto out; 9851da177e4SLinus Torvalds 986f1adc05eSJeff Dike return 0; 9871da177e4SLinus Torvalds 9881da177e4SLinus Torvalds out_put: 9891da177e4SLinus Torvalds iput(root_inode); 9901da177e4SLinus Torvalds out: 991f1adc05eSJeff Dike return err; 9921da177e4SLinus Torvalds } 9931da177e4SLinus Torvalds 9943c26ff6eSAl Viro static struct dentry *hostfs_read_sb(struct file_system_type *type, 9951da177e4SLinus Torvalds int flags, const char *dev_name, 9963c26ff6eSAl Viro void *data) 9971da177e4SLinus Torvalds { 9983c26ff6eSAl Viro return mount_nodev(type, flags, data, hostfs_fill_sb_common); 9991da177e4SLinus Torvalds } 10001da177e4SLinus Torvalds 1001601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 1002601d2c38SAl Viro { 1003601d2c38SAl Viro kill_anon_super(s); 1004601d2c38SAl Viro kfree(s->s_fs_info); 1005601d2c38SAl Viro } 1006601d2c38SAl Viro 10071da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 10081da177e4SLinus Torvalds .owner = THIS_MODULE, 10091da177e4SLinus Torvalds .name = "hostfs", 10103c26ff6eSAl Viro .mount = hostfs_read_sb, 1011601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 10121da177e4SLinus Torvalds .fs_flags = 0, 10131da177e4SLinus Torvalds }; 10143e64fe5bSEric W. Biederman MODULE_ALIAS_FS("hostfs"); 10151da177e4SLinus Torvalds 10161da177e4SLinus Torvalds static int __init init_hostfs(void) 10171da177e4SLinus Torvalds { 1018f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 10191da177e4SLinus Torvalds } 10201da177e4SLinus Torvalds 10211da177e4SLinus Torvalds static void __exit exit_hostfs(void) 10221da177e4SLinus Torvalds { 10231da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 10241da177e4SLinus Torvalds } 10251da177e4SLinus Torvalds 10261da177e4SLinus Torvalds module_init(init_hostfs) 10271da177e4SLinus Torvalds module_exit(exit_hostfs) 10281da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1029