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> 101da177e4SLinus Torvalds #include <linux/module.h> 1184b3db04SJeff Dike #include <linux/mm.h> 121da177e4SLinus Torvalds #include <linux/pagemap.h> 131da177e4SLinus Torvalds #include <linux/statfs.h> 145a0e3ad6STejun Heo #include <linux/slab.h> 15dd2cc4dfSMiklos Szeredi #include <linux/seq_file.h> 166966a977SJiri Kosina #include <linux/mount.h> 17d0352d3eSAl Viro #include <linux/namei.h> 181da177e4SLinus Torvalds #include "hostfs.h" 191da177e4SLinus Torvalds #include "init.h" 2084b3db04SJeff Dike #include "kern.h" 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds struct hostfs_inode_info { 231da177e4SLinus Torvalds int fd; 24aeb5d727SAl Viro fmode_t mode; 251da177e4SLinus Torvalds struct inode vfs_inode; 261da177e4SLinus Torvalds }; 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) 291da177e4SLinus Torvalds { 30f1adc05eSJeff Dike return list_entry(inode, struct hostfs_inode_info, vfs_inode); 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds 33680b0da9SJosef Sipek #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) 341da177e4SLinus Torvalds 35fe15ce44SNick Piggin static int hostfs_d_delete(const struct dentry *dentry) 361da177e4SLinus Torvalds { 37f1adc05eSJeff Dike return 1; 381da177e4SLinus Torvalds } 391da177e4SLinus Torvalds 40e16404edSAl Viro static const struct dentry_operations hostfs_dentry_ops = { 411da177e4SLinus Torvalds .d_delete = hostfs_d_delete, 421da177e4SLinus Torvalds }; 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds /* Changed in hostfs_args before the kernel starts running */ 45a6eb0be6SPaolo 'Blaisorblade' Giarrusso static char *root_ino = ""; 461da177e4SLinus Torvalds static int append = 0; 471da177e4SLinus Torvalds 481da177e4SLinus Torvalds #define HOSTFS_SUPER_MAGIC 0x00c0ffee 491da177e4SLinus Torvalds 5092e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops; 5192e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops; 52d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops; 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds #ifndef MODULE 551da177e4SLinus Torvalds static int __init hostfs_args(char *options, int *add) 561da177e4SLinus Torvalds { 571da177e4SLinus Torvalds char *ptr; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds ptr = strchr(options, ','); 601da177e4SLinus Torvalds if (ptr != NULL) 611da177e4SLinus Torvalds *ptr++ = '\0'; 621da177e4SLinus Torvalds if (*options != '\0') 631da177e4SLinus Torvalds root_ino = options; 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds options = ptr; 661da177e4SLinus Torvalds while (options) { 671da177e4SLinus Torvalds ptr = strchr(options, ','); 681da177e4SLinus Torvalds if (ptr != NULL) 691da177e4SLinus Torvalds *ptr++ = '\0'; 701da177e4SLinus Torvalds if (*options != '\0') { 711da177e4SLinus Torvalds if (!strcmp(options, "append")) 721da177e4SLinus Torvalds append = 1; 731da177e4SLinus Torvalds else printf("hostfs_args - unsupported option - %s\n", 741da177e4SLinus Torvalds options); 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds options = ptr; 771da177e4SLinus Torvalds } 78f1adc05eSJeff Dike return 0; 791da177e4SLinus Torvalds } 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds __uml_setup("hostfs=", hostfs_args, 821da177e4SLinus Torvalds "hostfs=<root dir>,<flags>,...\n" 831da177e4SLinus Torvalds " This is used to set hostfs parameters. The root directory argument\n" 841da177e4SLinus Torvalds " is used to confine all hostfs mounts to within the specified directory\n" 851da177e4SLinus Torvalds " tree on the host. If this isn't specified, then a user inside UML can\n" 861da177e4SLinus Torvalds " mount anything on the host that's accessible to the user that's running\n" 871da177e4SLinus Torvalds " it.\n" 881da177e4SLinus Torvalds " The only flag currently supported is 'append', which specifies that all\n" 891da177e4SLinus Torvalds " files opened by hostfs will be opened in append mode.\n\n" 901da177e4SLinus Torvalds ); 911da177e4SLinus Torvalds #endif 921da177e4SLinus Torvalds 93e9193059SAl Viro static char *__dentry_name(struct dentry *dentry, char *name) 94e9193059SAl Viro { 95ec2447c2SNick Piggin char *p = dentry_path_raw(dentry, name, PATH_MAX); 96e9193059SAl Viro char *root; 97e9193059SAl Viro size_t len; 98e9193059SAl Viro 99e9193059SAl Viro root = dentry->d_sb->s_fs_info; 100e9193059SAl Viro len = strlen(root); 101e9193059SAl Viro if (IS_ERR(p)) { 102e9193059SAl Viro __putname(name); 103e9193059SAl Viro return NULL; 104e9193059SAl Viro } 105850a496fSAl Viro strlcpy(name, root, PATH_MAX); 106e9193059SAl Viro if (len > p - name) { 107e9193059SAl Viro __putname(name); 108e9193059SAl Viro return NULL; 109e9193059SAl Viro } 110e9193059SAl Viro if (p > name + len) { 111e9193059SAl Viro char *s = name + len; 112e9193059SAl Viro while ((*s++ = *p++) != '\0') 113e9193059SAl Viro ; 114e9193059SAl Viro } 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 124e9193059SAl Viro return __dentry_name(dentry, name); /* will unlock */ 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 int len, n; 1461da177e4SLinus Torvalds char *name, *resolved, *end; 1471da177e4SLinus Torvalds 1481da177e4SLinus Torvalds len = 64; 1491da177e4SLinus Torvalds while (1) { 1501da177e4SLinus Torvalds n = -ENOMEM; 1511da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1521da177e4SLinus Torvalds if (name == NULL) 1531da177e4SLinus Torvalds goto out; 1541da177e4SLinus Torvalds 155ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1561da177e4SLinus Torvalds if (n < len) 1571da177e4SLinus Torvalds break; 1581da177e4SLinus Torvalds len *= 2; 1591da177e4SLinus Torvalds kfree(name); 1601da177e4SLinus Torvalds } 1611da177e4SLinus Torvalds if (n < 0) 1621da177e4SLinus Torvalds goto out_free; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds if (*name == '/') 165f1adc05eSJeff Dike return name; 1661da177e4SLinus Torvalds 1671da177e4SLinus Torvalds end = strrchr(link, '/'); 1681da177e4SLinus Torvalds if (end == NULL) 169f1adc05eSJeff Dike return name; 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds *(end + 1) = '\0'; 1721da177e4SLinus Torvalds len = strlen(link) + strlen(name) + 1; 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1751da177e4SLinus Torvalds if (resolved == NULL) { 1761da177e4SLinus Torvalds n = -ENOMEM; 1771da177e4SLinus Torvalds goto out_free; 1781da177e4SLinus Torvalds } 1791da177e4SLinus Torvalds 1801da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1811da177e4SLinus Torvalds kfree(name); 1821da177e4SLinus Torvalds kfree(link); 183f1adc05eSJeff Dike return resolved; 1841da177e4SLinus Torvalds 1851da177e4SLinus Torvalds out_free: 1861da177e4SLinus Torvalds kfree(name); 1871da177e4SLinus Torvalds out: 188f1adc05eSJeff Dike return ERR_PTR(n); 1891da177e4SLinus Torvalds } 1901da177e4SLinus Torvalds 1910a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1920a370e5dSDavid Howells { 19352b209f7SAl Viro struct inode *inode = new_inode(sb); 1940a370e5dSDavid Howells if (!inode) 1950a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 1960a370e5dSDavid Howells return inode; 1970a370e5dSDavid Howells } 1980a370e5dSDavid Howells 199726c3342SDavid Howells int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 2001da177e4SLinus Torvalds { 20184b3db04SJeff Dike /* 20284b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 2031da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 2041da177e4SLinus Torvalds * so we convert them here 2051da177e4SLinus Torvalds */ 2061da177e4SLinus Torvalds int err; 2071da177e4SLinus Torvalds long long f_blocks; 2081da177e4SLinus Torvalds long long f_bfree; 2091da177e4SLinus Torvalds long long f_bavail; 2101da177e4SLinus Torvalds long long f_files; 2111da177e4SLinus Torvalds long long f_ffree; 2121da177e4SLinus Torvalds 213601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2141da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2151da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2161b627d57SRichard Weinberger &sf->f_namelen); 217f1adc05eSJeff Dike if (err) 218f1adc05eSJeff Dike return err; 2191da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2201da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2211da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2221da177e4SLinus Torvalds sf->f_files = f_files; 2231da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2241da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 225f1adc05eSJeff Dike return 0; 2261da177e4SLinus Torvalds } 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2291da177e4SLinus Torvalds { 2301da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2311da177e4SLinus Torvalds 232601d2c38SAl Viro hi = kzalloc(sizeof(*hi), GFP_KERNEL); 2331da177e4SLinus Torvalds if (hi == NULL) 234f1adc05eSJeff Dike return NULL; 235601d2c38SAl Viro hi->fd = -1; 2361da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 237f1adc05eSJeff Dike return &hi->vfs_inode; 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 240e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2411da177e4SLinus Torvalds { 242fef26658SMark Fasheh truncate_inode_pages(&inode->i_data, 0); 243e971a6d7SAl Viro end_writeback(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 INIT_LIST_HEAD(&inode->i_dentry); 254fa0d7e3dSNick Piggin kfree(HOSTFS_I(inode)); 255fa0d7e3dSNick Piggin } 256fa0d7e3dSNick Piggin 2571da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 2581da177e4SLinus Torvalds { 259fa0d7e3dSNick Piggin call_rcu(&inode->i_rcu, hostfs_i_callback); 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 262dd2cc4dfSMiklos Szeredi static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 263dd2cc4dfSMiklos Szeredi { 264601d2c38SAl Viro const char *root_path = vfs->mnt_sb->s_fs_info; 265dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 266dd2cc4dfSMiklos Szeredi 267dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 268dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 269dd2cc4dfSMiklos Szeredi 270dd2cc4dfSMiklos Szeredi return 0; 271dd2cc4dfSMiklos Szeredi } 272dd2cc4dfSMiklos Szeredi 273ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 2741da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 2751da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 276e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 2771da177e4SLinus Torvalds .statfs = hostfs_statfs, 278dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 2791da177e4SLinus Torvalds }; 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) 2821da177e4SLinus Torvalds { 2831da177e4SLinus Torvalds void *dir; 2841da177e4SLinus Torvalds char *name; 2851da177e4SLinus Torvalds unsigned long long next, ino; 2861da177e4SLinus Torvalds int error, len; 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; 2951da177e4SLinus Torvalds next = file->f_pos; 2961da177e4SLinus Torvalds while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { 2971da177e4SLinus Torvalds error = (*filldir)(ent, name, len, file->f_pos, 2981da177e4SLinus Torvalds ino, DT_UNKNOWN); 2991da177e4SLinus Torvalds if (error) break; 3001da177e4SLinus Torvalds file->f_pos = next; 3011da177e4SLinus Torvalds } 3021da177e4SLinus Torvalds close_dir(dir); 303f1adc05eSJeff Dike return 0; 3041da177e4SLinus Torvalds } 3051da177e4SLinus Torvalds 3061da177e4SLinus Torvalds int hostfs_file_open(struct inode *ino, struct file *file) 3071da177e4SLinus Torvalds { 308f8ad850fSAl Viro static DEFINE_MUTEX(open_mutex); 3091da177e4SLinus Torvalds char *name; 310aeb5d727SAl Viro fmode_t mode = 0; 311f8ad850fSAl Viro int err; 312aeb5d727SAl Viro int r = 0, w = 0, fd; 3131da177e4SLinus Torvalds 3141da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3151da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 316f1adc05eSJeff Dike return 0; 3171da177e4SLinus Torvalds 318f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 3191da177e4SLinus Torvalds 320f8ad850fSAl Viro retry: 321f8ad850fSAl Viro if (mode & FMODE_READ) 3221da177e4SLinus Torvalds r = 1; 323f8ad850fSAl Viro if (mode & FMODE_WRITE) 3241da177e4SLinus Torvalds w = 1; 3251da177e4SLinus Torvalds if (w) 3261da177e4SLinus Torvalds r = 1; 3271da177e4SLinus Torvalds 328c5322220SAl Viro name = dentry_name(file->f_path.dentry); 3291da177e4SLinus Torvalds if (name == NULL) 330f1adc05eSJeff Dike return -ENOMEM; 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds fd = open_file(name, r, w, append); 333e9193059SAl Viro __putname(name); 334f1adc05eSJeff Dike if (fd < 0) 335f1adc05eSJeff Dike return fd; 336f8ad850fSAl Viro 337f8ad850fSAl Viro mutex_lock(&open_mutex); 338f8ad850fSAl Viro /* somebody else had handled it first? */ 339f8ad850fSAl Viro if ((mode & HOSTFS_I(ino)->mode) == mode) { 340f8ad850fSAl Viro mutex_unlock(&open_mutex); 341f8ad850fSAl Viro return 0; 342f8ad850fSAl Viro } 343f8ad850fSAl Viro if ((mode | HOSTFS_I(ino)->mode) != mode) { 344f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode; 345f8ad850fSAl Viro mutex_unlock(&open_mutex); 346f8ad850fSAl Viro close_file(&fd); 347f8ad850fSAl Viro goto retry; 348f8ad850fSAl Viro } 349f8ad850fSAl Viro if (HOSTFS_I(ino)->fd == -1) { 350f8ad850fSAl Viro HOSTFS_I(ino)->fd = fd; 351f8ad850fSAl Viro } else { 352f8ad850fSAl Viro err = replace_file(fd, HOSTFS_I(ino)->fd); 353f8ad850fSAl Viro close_file(&fd); 354f8ad850fSAl Viro if (err < 0) { 355f8ad850fSAl Viro mutex_unlock(&open_mutex); 356f8ad850fSAl Viro return err; 357f8ad850fSAl Viro } 358f8ad850fSAl Viro } 359f8ad850fSAl Viro HOSTFS_I(ino)->mode = mode; 360f8ad850fSAl Viro mutex_unlock(&open_mutex); 3611da177e4SLinus Torvalds 362f1adc05eSJeff Dike return 0; 3631da177e4SLinus Torvalds } 3641da177e4SLinus Torvalds 3657ea80859SChristoph Hellwig int hostfs_fsync(struct file *file, int datasync) 3661da177e4SLinus Torvalds { 3677ea80859SChristoph Hellwig return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); 3681da177e4SLinus Torvalds } 3691da177e4SLinus Torvalds 3704b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3711da177e4SLinus Torvalds .llseek = generic_file_llseek, 372543ade1fSBadari Pulavarty .read = do_sync_read, 3735ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 3741da177e4SLinus Torvalds .aio_read = generic_file_aio_read, 3751da177e4SLinus Torvalds .aio_write = generic_file_aio_write, 376543ade1fSBadari Pulavarty .write = do_sync_write, 3771da177e4SLinus Torvalds .mmap = generic_file_mmap, 3781da177e4SLinus Torvalds .open = hostfs_file_open, 3791da177e4SLinus Torvalds .release = NULL, 3801da177e4SLinus Torvalds .fsync = hostfs_fsync, 3811da177e4SLinus Torvalds }; 3821da177e4SLinus Torvalds 3834b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 3841da177e4SLinus Torvalds .llseek = generic_file_llseek, 3851da177e4SLinus Torvalds .readdir = hostfs_readdir, 3861da177e4SLinus Torvalds .read = generic_read_dir, 3871da177e4SLinus Torvalds }; 3881da177e4SLinus Torvalds 3891da177e4SLinus Torvalds int hostfs_writepage(struct page *page, struct writeback_control *wbc) 3901da177e4SLinus Torvalds { 3911da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 3921da177e4SLinus Torvalds struct inode *inode = mapping->host; 3931da177e4SLinus Torvalds char *buffer; 3941da177e4SLinus Torvalds unsigned long long base; 3951da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 3961da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 3971da177e4SLinus Torvalds int err; 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds if (page->index >= end_index) 4001da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 4011da177e4SLinus Torvalds 4021da177e4SLinus Torvalds buffer = kmap(page); 4031da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 4041da177e4SLinus Torvalds 4051da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4061da177e4SLinus Torvalds if (err != count) { 4071da177e4SLinus Torvalds ClearPageUptodate(page); 4081da177e4SLinus Torvalds goto out; 4091da177e4SLinus Torvalds } 4101da177e4SLinus Torvalds 4111da177e4SLinus Torvalds if (base > inode->i_size) 4121da177e4SLinus Torvalds inode->i_size = base; 4131da177e4SLinus Torvalds 4141da177e4SLinus Torvalds if (PageError(page)) 4151da177e4SLinus Torvalds ClearPageError(page); 4161da177e4SLinus Torvalds err = 0; 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds out: 4191da177e4SLinus Torvalds kunmap(page); 4201da177e4SLinus Torvalds 4211da177e4SLinus Torvalds unlock_page(page); 4221da177e4SLinus Torvalds return err; 4231da177e4SLinus Torvalds } 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds int hostfs_readpage(struct file *file, struct page *page) 4261da177e4SLinus Torvalds { 4271da177e4SLinus Torvalds char *buffer; 4281da177e4SLinus Torvalds long long start; 4291da177e4SLinus Torvalds int err = 0; 4301da177e4SLinus Torvalds 4311da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4321da177e4SLinus Torvalds buffer = kmap(page); 4331da177e4SLinus Torvalds err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4341da177e4SLinus Torvalds PAGE_CACHE_SIZE); 43584b3db04SJeff Dike if (err < 0) 43684b3db04SJeff Dike goto out; 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds flush_dcache_page(page); 4411da177e4SLinus Torvalds SetPageUptodate(page); 4421da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 4431da177e4SLinus Torvalds err = 0; 4441da177e4SLinus Torvalds out: 4451da177e4SLinus Torvalds kunmap(page); 4461da177e4SLinus Torvalds unlock_page(page); 447f1adc05eSJeff Dike return err; 4481da177e4SLinus Torvalds } 4491da177e4SLinus Torvalds 450ae361ff4SNick Piggin int hostfs_write_begin(struct file *file, struct address_space *mapping, 451ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 452ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4531da177e4SLinus Torvalds { 454ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 455ae361ff4SNick Piggin 45654566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 457ae361ff4SNick Piggin if (!*pagep) 458ae361ff4SNick Piggin return -ENOMEM; 459ae361ff4SNick Piggin return 0; 460ae361ff4SNick Piggin } 461ae361ff4SNick Piggin 462ae361ff4SNick Piggin int hostfs_write_end(struct file *file, struct address_space *mapping, 463ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 464ae361ff4SNick Piggin struct page *page, void *fsdata) 465ae361ff4SNick Piggin { 466ae361ff4SNick Piggin struct inode *inode = mapping->host; 467ae361ff4SNick Piggin void *buffer; 468ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 4691da177e4SLinus Torvalds int err; 4701da177e4SLinus Torvalds 4711da177e4SLinus Torvalds buffer = kmap(page); 472ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 4731da177e4SLinus Torvalds kunmap(page); 4741da177e4SLinus Torvalds 475ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 476ae361ff4SNick Piggin SetPageUptodate(page); 4771da177e4SLinus Torvalds 47884b3db04SJeff Dike /* 47984b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 480ae361ff4SNick Piggin * i_size against the last byte written. 481ae361ff4SNick Piggin */ 482ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 483ae361ff4SNick Piggin inode->i_size = pos; 484ae361ff4SNick Piggin unlock_page(page); 485ae361ff4SNick Piggin page_cache_release(page); 48630f04a4eSPaolo 'Blaisorblade' Giarrusso 487f1adc05eSJeff Dike return err; 4881da177e4SLinus Torvalds } 4891da177e4SLinus Torvalds 490f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 4911da177e4SLinus Torvalds .writepage = hostfs_writepage, 4921da177e4SLinus Torvalds .readpage = hostfs_readpage, 493ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 494ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 495ae361ff4SNick Piggin .write_end = hostfs_write_end, 4961da177e4SLinus Torvalds }; 4971da177e4SLinus Torvalds 4984754b825SAl Viro static int read_name(struct inode *ino, char *name) 4991da177e4SLinus Torvalds { 5004754b825SAl Viro dev_t rdev; 5014754b825SAl Viro struct hostfs_stat st; 5024754b825SAl Viro int err = stat_file(name, &st, -1); 5034754b825SAl Viro if (err) 5044754b825SAl Viro return err; 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 5074754b825SAl Viro rdev = MKDEV(st.maj, st.min); 5081da177e4SLinus Torvalds 5094754b825SAl Viro switch (st.mode & S_IFMT) { 5104754b825SAl Viro case S_IFLNK: 511d0352d3eSAl Viro ino->i_op = &hostfs_link_iops; 5124754b825SAl Viro break; 5134754b825SAl Viro case S_IFDIR: 5144754b825SAl Viro ino->i_op = &hostfs_dir_iops; 5154754b825SAl Viro ino->i_fop = &hostfs_dir_fops; 5164754b825SAl Viro break; 5174754b825SAl Viro case S_IFCHR: 5184754b825SAl Viro case S_IFBLK: 5194754b825SAl Viro case S_IFIFO: 5204754b825SAl Viro case S_IFSOCK: 5214754b825SAl Viro init_special_inode(ino, st.mode & S_IFMT, rdev); 5224754b825SAl Viro ino->i_op = &hostfs_iops; 5234754b825SAl Viro break; 5241da177e4SLinus Torvalds 5254754b825SAl Viro default: 5264754b825SAl Viro ino->i_op = &hostfs_iops; 5274754b825SAl Viro ino->i_fop = &hostfs_file_fops; 5284754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops; 5291da177e4SLinus Torvalds } 5304754b825SAl Viro 5314754b825SAl Viro ino->i_ino = st.ino; 5324754b825SAl Viro ino->i_mode = st.mode; 5334754b825SAl Viro ino->i_nlink = st.nlink; 5344754b825SAl Viro ino->i_uid = st.uid; 5354754b825SAl Viro ino->i_gid = st.gid; 5364754b825SAl Viro ino->i_atime = st.atime; 5374754b825SAl Viro ino->i_mtime = st.mtime; 5384754b825SAl Viro ino->i_ctime = st.ctime; 5394754b825SAl Viro ino->i_size = st.size; 5404754b825SAl Viro ino->i_blocks = st.blocks; 5414754b825SAl Viro return 0; 5421da177e4SLinus Torvalds } 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, 5451da177e4SLinus Torvalds struct nameidata *nd) 5461da177e4SLinus Torvalds { 5471da177e4SLinus Torvalds struct inode *inode; 5481da177e4SLinus Torvalds char *name; 5491da177e4SLinus Torvalds int error, fd; 5501da177e4SLinus Torvalds 5510a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5520a370e5dSDavid Howells if (IS_ERR(inode)) { 5530a370e5dSDavid Howells error = PTR_ERR(inode); 55484b3db04SJeff Dike goto out; 5550a370e5dSDavid Howells } 5561da177e4SLinus Torvalds 5571da177e4SLinus Torvalds error = -ENOMEM; 558c5322220SAl Viro name = dentry_name(dentry); 5591da177e4SLinus Torvalds if (name == NULL) 5601da177e4SLinus Torvalds goto out_put; 5611da177e4SLinus Torvalds 5621da177e4SLinus Torvalds fd = file_create(name, 5631da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 5641da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 5651da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 5664754b825SAl Viro if (fd < 0) 5671da177e4SLinus Torvalds error = fd; 5684754b825SAl Viro else 5695e2df28cSAl Viro error = read_name(inode, name); 5701da177e4SLinus Torvalds 571e9193059SAl Viro __putname(name); 5721da177e4SLinus Torvalds if (error) 5731da177e4SLinus Torvalds goto out_put; 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 5761da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 5771da177e4SLinus Torvalds d_instantiate(dentry, inode); 578f1adc05eSJeff Dike return 0; 5791da177e4SLinus Torvalds 5801da177e4SLinus Torvalds out_put: 5811da177e4SLinus Torvalds iput(inode); 5821da177e4SLinus Torvalds out: 583f1adc05eSJeff Dike return error; 5841da177e4SLinus Torvalds } 5851da177e4SLinus Torvalds 5861da177e4SLinus Torvalds struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 5871da177e4SLinus Torvalds struct nameidata *nd) 5881da177e4SLinus Torvalds { 5891da177e4SLinus Torvalds struct inode *inode; 5901da177e4SLinus Torvalds char *name; 5911da177e4SLinus Torvalds int err; 5921da177e4SLinus Torvalds 5930a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 5940a370e5dSDavid Howells if (IS_ERR(inode)) { 5950a370e5dSDavid Howells err = PTR_ERR(inode); 5961da177e4SLinus Torvalds goto out; 5970a370e5dSDavid Howells } 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds err = -ENOMEM; 600c5322220SAl Viro name = dentry_name(dentry); 6011da177e4SLinus Torvalds if (name == NULL) 6021da177e4SLinus Torvalds goto out_put; 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds err = read_name(inode, name); 6055e2df28cSAl Viro 606e9193059SAl Viro __putname(name); 6071da177e4SLinus Torvalds if (err == -ENOENT) { 6081da177e4SLinus Torvalds iput(inode); 6091da177e4SLinus Torvalds inode = NULL; 6101da177e4SLinus Torvalds } 6111da177e4SLinus Torvalds else if (err) 6121da177e4SLinus Torvalds goto out_put; 6131da177e4SLinus Torvalds 6141da177e4SLinus Torvalds d_add(dentry, inode); 615fb045adbSNick Piggin d_set_d_op(dentry, &hostfs_dentry_ops); 616f1adc05eSJeff Dike return NULL; 6171da177e4SLinus Torvalds 6181da177e4SLinus Torvalds out_put: 6191da177e4SLinus Torvalds iput(inode); 6201da177e4SLinus Torvalds out: 621f1adc05eSJeff Dike return ERR_PTR(err); 6221da177e4SLinus Torvalds } 6231da177e4SLinus Torvalds 6241da177e4SLinus Torvalds int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) 6251da177e4SLinus Torvalds { 6261da177e4SLinus Torvalds char *from_name, *to_name; 6271da177e4SLinus Torvalds int err; 6281da177e4SLinus Torvalds 629c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 630f1adc05eSJeff Dike return -ENOMEM; 631c5322220SAl Viro to_name = dentry_name(to); 6321da177e4SLinus Torvalds if (to_name == NULL) { 633e9193059SAl Viro __putname(from_name); 634f1adc05eSJeff Dike return -ENOMEM; 6351da177e4SLinus Torvalds } 6361da177e4SLinus Torvalds err = link_file(to_name, from_name); 637e9193059SAl Viro __putname(from_name); 638e9193059SAl Viro __putname(to_name); 639f1adc05eSJeff Dike return err; 6401da177e4SLinus Torvalds } 6411da177e4SLinus Torvalds 6421da177e4SLinus Torvalds int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6431da177e4SLinus Torvalds { 6441da177e4SLinus Torvalds char *file; 6451da177e4SLinus Torvalds int err; 6461da177e4SLinus Torvalds 6471da177e4SLinus Torvalds if (append) 648f1adc05eSJeff Dike return -EPERM; 6491da177e4SLinus Torvalds 650f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL) 651f8d7e187SAl Viro return -ENOMEM; 652f8d7e187SAl Viro 6531da177e4SLinus Torvalds err = unlink_file(file); 654e9193059SAl Viro __putname(file); 655f1adc05eSJeff Dike return err; 6561da177e4SLinus Torvalds } 6571da177e4SLinus Torvalds 6581da177e4SLinus Torvalds int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) 6591da177e4SLinus Torvalds { 6601da177e4SLinus Torvalds char *file; 6611da177e4SLinus Torvalds int err; 6621da177e4SLinus Torvalds 663c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 664f1adc05eSJeff Dike return -ENOMEM; 6651da177e4SLinus Torvalds err = make_symlink(file, to); 666e9193059SAl Viro __putname(file); 667f1adc05eSJeff Dike return err; 6681da177e4SLinus Torvalds } 6691da177e4SLinus Torvalds 6701da177e4SLinus Torvalds int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) 6711da177e4SLinus Torvalds { 6721da177e4SLinus Torvalds char *file; 6731da177e4SLinus Torvalds int err; 6741da177e4SLinus Torvalds 675c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 676f1adc05eSJeff Dike return -ENOMEM; 6771da177e4SLinus Torvalds err = do_mkdir(file, mode); 678e9193059SAl Viro __putname(file); 679f1adc05eSJeff Dike return err; 6801da177e4SLinus Torvalds } 6811da177e4SLinus Torvalds 6821da177e4SLinus Torvalds int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 6831da177e4SLinus Torvalds { 6841da177e4SLinus Torvalds char *file; 6851da177e4SLinus Torvalds int err; 6861da177e4SLinus Torvalds 687c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 688f1adc05eSJeff Dike return -ENOMEM; 6891da177e4SLinus Torvalds err = do_rmdir(file); 690e9193059SAl Viro __putname(file); 691f1adc05eSJeff Dike return err; 6921da177e4SLinus Torvalds } 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvalds int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 6951da177e4SLinus Torvalds { 6961da177e4SLinus Torvalds struct inode *inode; 6971da177e4SLinus Torvalds char *name; 6980a370e5dSDavid Howells int err; 6991da177e4SLinus Torvalds 7000a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7010a370e5dSDavid Howells if (IS_ERR(inode)) { 7020a370e5dSDavid Howells err = PTR_ERR(inode); 7031da177e4SLinus Torvalds goto out; 7040a370e5dSDavid Howells } 7051da177e4SLinus Torvalds 7061da177e4SLinus Torvalds err = -ENOMEM; 707c5322220SAl Viro name = dentry_name(dentry); 7081da177e4SLinus Torvalds if (name == NULL) 7091da177e4SLinus Torvalds goto out_put; 7101da177e4SLinus Torvalds 7111da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 71288f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 713e9193059SAl Viro if (!err) 7141da177e4SLinus Torvalds goto out_free; 7151da177e4SLinus Torvalds 7161da177e4SLinus Torvalds err = read_name(inode, name); 717e9193059SAl Viro __putname(name); 7185e2df28cSAl Viro if (err) 7195e2df28cSAl Viro goto out_put; 7201da177e4SLinus Torvalds if (err) 7211da177e4SLinus Torvalds goto out_put; 7221da177e4SLinus Torvalds 7231da177e4SLinus Torvalds d_instantiate(dentry, inode); 724f1adc05eSJeff Dike return 0; 7251da177e4SLinus Torvalds 7261da177e4SLinus Torvalds out_free: 727e9193059SAl Viro __putname(name); 7281da177e4SLinus Torvalds out_put: 7291da177e4SLinus Torvalds iput(inode); 7301da177e4SLinus Torvalds out: 731f1adc05eSJeff Dike return err; 7321da177e4SLinus Torvalds } 7331da177e4SLinus Torvalds 7341da177e4SLinus Torvalds int hostfs_rename(struct inode *from_ino, struct dentry *from, 7351da177e4SLinus Torvalds struct inode *to_ino, struct dentry *to) 7361da177e4SLinus Torvalds { 7371da177e4SLinus Torvalds char *from_name, *to_name; 7381da177e4SLinus Torvalds int err; 7391da177e4SLinus Torvalds 740c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 741f1adc05eSJeff Dike return -ENOMEM; 742c5322220SAl Viro if ((to_name = dentry_name(to)) == NULL) { 743e9193059SAl Viro __putname(from_name); 744f1adc05eSJeff Dike return -ENOMEM; 7451da177e4SLinus Torvalds } 7461da177e4SLinus Torvalds err = rename_file(from_name, to_name); 747e9193059SAl Viro __putname(from_name); 748e9193059SAl Viro __putname(to_name); 749f1adc05eSJeff Dike return err; 7501da177e4SLinus Torvalds } 7511da177e4SLinus Torvalds 752b74c79e9SNick Piggin int hostfs_permission(struct inode *ino, int desired, unsigned int flags) 7531da177e4SLinus Torvalds { 7541da177e4SLinus Torvalds char *name; 7551da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7561da177e4SLinus Torvalds 757b74c79e9SNick Piggin if (flags & IPERM_FLAG_RCU) 758b74c79e9SNick Piggin return -ECHILD; 759b74c79e9SNick Piggin 7601da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7611da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7621da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 763c5322220SAl Viro name = inode_name(ino); 764f1adc05eSJeff Dike if (name == NULL) 765f1adc05eSJeff Dike return -ENOMEM; 7661da177e4SLinus Torvalds 7671da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 7681da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 7691da177e4SLinus Torvalds err = 0; 7701da177e4SLinus Torvalds else 7711da177e4SLinus Torvalds err = access_file(name, r, w, x); 772e9193059SAl Viro __putname(name); 7731da177e4SLinus Torvalds if (!err) 774b74c79e9SNick Piggin err = generic_permission(ino, desired, flags, NULL); 7751da177e4SLinus Torvalds return err; 7761da177e4SLinus Torvalds } 7771da177e4SLinus Torvalds 7781da177e4SLinus Torvalds int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 7791da177e4SLinus Torvalds { 7801025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 7811da177e4SLinus Torvalds struct hostfs_iattr attrs; 7821da177e4SLinus Torvalds char *name; 7831da177e4SLinus Torvalds int err; 7841da177e4SLinus Torvalds 7851025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 7865822b7faSAlberto Bertogli 7871025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 7881da177e4SLinus Torvalds if (err) 7891da177e4SLinus Torvalds return err; 7901da177e4SLinus Torvalds 7911da177e4SLinus Torvalds if (append) 7921da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 7931da177e4SLinus Torvalds 7941da177e4SLinus Torvalds attrs.ia_valid = 0; 7951da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 7961da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 7971da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 7981da177e4SLinus Torvalds } 7991da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8001da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 8011da177e4SLinus Torvalds attrs.ia_uid = attr->ia_uid; 8021da177e4SLinus Torvalds } 8031da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8041da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 8051da177e4SLinus Torvalds attrs.ia_gid = attr->ia_gid; 8061da177e4SLinus Torvalds } 8071da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8081da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8091da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8101da177e4SLinus Torvalds } 8111da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8121da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 8131da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 8141da177e4SLinus Torvalds } 8151da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8161da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 8171da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 8181da177e4SLinus Torvalds } 8191da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8201da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 8211da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 8221da177e4SLinus Torvalds } 8231da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8241da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8251da177e4SLinus Torvalds } 8261da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8271da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8281da177e4SLinus Torvalds } 829c5322220SAl Viro name = dentry_name(dentry); 830f1adc05eSJeff Dike if (name == NULL) 831f1adc05eSJeff Dike return -ENOMEM; 8325822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 833e9193059SAl Viro __putname(name); 8341da177e4SLinus Torvalds if (err) 835f1adc05eSJeff Dike return err; 8361da177e4SLinus Torvalds 8371025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 8381025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 8391025774cSChristoph Hellwig int error; 8401025774cSChristoph Hellwig 8411025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 8421025774cSChristoph Hellwig if (err) 8431025774cSChristoph Hellwig return err; 8441025774cSChristoph Hellwig } 8451025774cSChristoph Hellwig 8461025774cSChristoph Hellwig setattr_copy(inode, attr); 8471025774cSChristoph Hellwig mark_inode_dirty(inode); 8481025774cSChristoph Hellwig return 0; 8491da177e4SLinus Torvalds } 8501da177e4SLinus Torvalds 85192e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8521da177e4SLinus Torvalds .create = hostfs_create, 8531da177e4SLinus Torvalds .link = hostfs_link, 8541da177e4SLinus Torvalds .unlink = hostfs_unlink, 8551da177e4SLinus Torvalds .symlink = hostfs_symlink, 8561da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8571da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8581da177e4SLinus Torvalds .mknod = hostfs_mknod, 8591da177e4SLinus Torvalds .rename = hostfs_rename, 8601da177e4SLinus Torvalds .permission = hostfs_permission, 8611da177e4SLinus Torvalds .setattr = hostfs_setattr, 8621da177e4SLinus Torvalds }; 8631da177e4SLinus Torvalds 86492e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8651da177e4SLinus Torvalds .create = hostfs_create, 8661da177e4SLinus Torvalds .lookup = hostfs_lookup, 8671da177e4SLinus Torvalds .link = hostfs_link, 8681da177e4SLinus Torvalds .unlink = hostfs_unlink, 8691da177e4SLinus Torvalds .symlink = hostfs_symlink, 8701da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8711da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8721da177e4SLinus Torvalds .mknod = hostfs_mknod, 8731da177e4SLinus Torvalds .rename = hostfs_rename, 8741da177e4SLinus Torvalds .permission = hostfs_permission, 8751da177e4SLinus Torvalds .setattr = hostfs_setattr, 8761da177e4SLinus Torvalds }; 8771da177e4SLinus Torvalds 878d0352d3eSAl Viro static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) 8791da177e4SLinus Torvalds { 880d0352d3eSAl Viro char *link = __getname(); 881d0352d3eSAl Viro if (link) { 882d0352d3eSAl Viro char *path = dentry_name(dentry); 883d0352d3eSAl Viro int err = -ENOMEM; 884d0352d3eSAl Viro if (path) { 8853b6036d1SAl Viro err = hostfs_do_readlink(path, link, PATH_MAX); 886d0352d3eSAl Viro if (err == PATH_MAX) 8871da177e4SLinus Torvalds err = -E2BIG; 888e9193059SAl Viro __putname(path); 8891da177e4SLinus Torvalds } 890d0352d3eSAl Viro if (err < 0) { 891d0352d3eSAl Viro __putname(link); 892d0352d3eSAl Viro link = ERR_PTR(err); 893d0352d3eSAl Viro } 894d0352d3eSAl Viro } else { 895d0352d3eSAl Viro link = ERR_PTR(-ENOMEM); 8961da177e4SLinus Torvalds } 8971da177e4SLinus Torvalds 898d0352d3eSAl Viro nd_set_link(nd, link); 899d0352d3eSAl Viro return NULL; 900d0352d3eSAl Viro } 901d0352d3eSAl Viro 902d0352d3eSAl Viro static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 903d0352d3eSAl Viro { 904d0352d3eSAl Viro char *s = nd_get_link(nd); 905d0352d3eSAl Viro if (!IS_ERR(s)) 906d0352d3eSAl Viro __putname(s); 907d0352d3eSAl Viro } 908d0352d3eSAl Viro 909d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 910d0352d3eSAl Viro .readlink = generic_readlink, 911d0352d3eSAl Viro .follow_link = hostfs_follow_link, 912d0352d3eSAl Viro .put_link = hostfs_put_link, 9131da177e4SLinus Torvalds }; 9141da177e4SLinus Torvalds 9151da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9161da177e4SLinus Torvalds { 9171da177e4SLinus Torvalds struct inode *root_inode; 91875e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9191da177e4SLinus Torvalds int err; 9201da177e4SLinus Torvalds 9211da177e4SLinus Torvalds sb->s_blocksize = 1024; 9221da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9231da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9241da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 925752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9261da177e4SLinus Torvalds 927a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 92875e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 92975e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9301da177e4SLinus Torvalds 9311da177e4SLinus Torvalds err = -ENOMEM; 932601d2c38SAl Viro sb->s_fs_info = host_root_path = 933601d2c38SAl Viro kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); 93475e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9351da177e4SLinus Torvalds goto out; 9361da177e4SLinus Torvalds 93775e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9381da177e4SLinus Torvalds 93952b209f7SAl Viro root_inode = new_inode(sb); 94052b209f7SAl Viro if (!root_inode) 941601d2c38SAl Viro goto out; 9421da177e4SLinus Torvalds 9434754b825SAl Viro err = read_name(root_inode, host_root_path); 9444754b825SAl Viro if (err) 9454754b825SAl Viro goto out_put; 94652b209f7SAl Viro 9474754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 94852b209f7SAl Viro char *name = follow_link(host_root_path); 94952b209f7SAl Viro if (IS_ERR(name)) 95052b209f7SAl Viro err = PTR_ERR(name); 95152b209f7SAl Viro else 95252b209f7SAl Viro err = read_name(root_inode, name); 95352b209f7SAl Viro kfree(name); 9541da177e4SLinus Torvalds if (err) 9551da177e4SLinus Torvalds goto out_put; 9564754b825SAl Viro } 9571da177e4SLinus Torvalds 9581da177e4SLinus Torvalds err = -ENOMEM; 9591da177e4SLinus Torvalds sb->s_root = d_alloc_root(root_inode); 9601da177e4SLinus Torvalds if (sb->s_root == NULL) 9611da177e4SLinus Torvalds goto out_put; 9621da177e4SLinus Torvalds 963f1adc05eSJeff Dike return 0; 9641da177e4SLinus Torvalds 9651da177e4SLinus Torvalds out_put: 9661da177e4SLinus Torvalds iput(root_inode); 9671da177e4SLinus Torvalds out: 968f1adc05eSJeff Dike return err; 9691da177e4SLinus Torvalds } 9701da177e4SLinus Torvalds 9713c26ff6eSAl Viro static struct dentry *hostfs_read_sb(struct file_system_type *type, 9721da177e4SLinus Torvalds int flags, const char *dev_name, 9733c26ff6eSAl Viro void *data) 9741da177e4SLinus Torvalds { 9753c26ff6eSAl Viro return mount_nodev(type, flags, data, hostfs_fill_sb_common); 9761da177e4SLinus Torvalds } 9771da177e4SLinus Torvalds 978601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 979601d2c38SAl Viro { 980601d2c38SAl Viro kill_anon_super(s); 981601d2c38SAl Viro kfree(s->s_fs_info); 982601d2c38SAl Viro } 983601d2c38SAl Viro 9841da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 9851da177e4SLinus Torvalds .owner = THIS_MODULE, 9861da177e4SLinus Torvalds .name = "hostfs", 9873c26ff6eSAl Viro .mount = hostfs_read_sb, 988601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 9891da177e4SLinus Torvalds .fs_flags = 0, 9901da177e4SLinus Torvalds }; 9911da177e4SLinus Torvalds 9921da177e4SLinus Torvalds static int __init init_hostfs(void) 9931da177e4SLinus Torvalds { 994f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 9951da177e4SLinus Torvalds } 9961da177e4SLinus Torvalds 9971da177e4SLinus Torvalds static void __exit exit_hostfs(void) 9981da177e4SLinus Torvalds { 9991da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 10001da177e4SLinus Torvalds } 10011da177e4SLinus Torvalds 10021da177e4SLinus Torvalds module_init(init_hostfs) 10031da177e4SLinus Torvalds module_exit(exit_hostfs) 10041da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1005