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> 171da177e4SLinus Torvalds #include "hostfs.h" 181da177e4SLinus Torvalds #include "init.h" 1984b3db04SJeff Dike #include "kern.h" 201da177e4SLinus Torvalds 211da177e4SLinus Torvalds struct hostfs_inode_info { 221da177e4SLinus Torvalds char *host_filename; 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 35e16404edSAl Viro static int hostfs_d_delete(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; 52f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_link_aops; 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 931da177e4SLinus Torvalds static char *dentry_name(struct dentry *dentry, int extra) 941da177e4SLinus Torvalds { 951da177e4SLinus Torvalds struct dentry *parent; 961da177e4SLinus Torvalds char *root, *name; 971da177e4SLinus Torvalds int len; 981da177e4SLinus Torvalds 991da177e4SLinus Torvalds len = 0; 1001da177e4SLinus Torvalds parent = dentry; 1011da177e4SLinus Torvalds while (parent->d_parent != parent) { 1021da177e4SLinus Torvalds len += parent->d_name.len + 1; 1031da177e4SLinus Torvalds parent = parent->d_parent; 1041da177e4SLinus Torvalds } 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds root = HOSTFS_I(parent->d_inode)->host_filename; 1071da177e4SLinus Torvalds len += strlen(root); 1081da177e4SLinus Torvalds name = kmalloc(len + extra + 1, GFP_KERNEL); 109f1adc05eSJeff Dike if (name == NULL) 110f1adc05eSJeff Dike return NULL; 1111da177e4SLinus Torvalds 1121da177e4SLinus Torvalds name[len] = '\0'; 1131da177e4SLinus Torvalds parent = dentry; 1141da177e4SLinus Torvalds while (parent->d_parent != parent) { 1151da177e4SLinus Torvalds len -= parent->d_name.len + 1; 1161da177e4SLinus Torvalds name[len] = '/'; 1171da177e4SLinus Torvalds strncpy(&name[len + 1], parent->d_name.name, 1181da177e4SLinus Torvalds parent->d_name.len); 1191da177e4SLinus Torvalds parent = parent->d_parent; 1201da177e4SLinus Torvalds } 1211da177e4SLinus Torvalds strncpy(name, root, strlen(root)); 122f1adc05eSJeff Dike return name; 1231da177e4SLinus Torvalds } 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds static char *inode_name(struct inode *ino, int extra) 1261da177e4SLinus Torvalds { 1271da177e4SLinus Torvalds struct dentry *dentry; 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); 130f1adc05eSJeff Dike return dentry_name(dentry, extra); 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds static int read_name(struct inode *ino, char *name) 1341da177e4SLinus Torvalds { 13584b3db04SJeff Dike /* 13684b3db04SJeff Dike * The non-int inode fields are copied into ints by stat_file and 1371da177e4SLinus Torvalds * then copied into the inode because passing the actual pointers 1381da177e4SLinus Torvalds * in and having them treated as int * breaks on big-endian machines 1391da177e4SLinus Torvalds */ 1401da177e4SLinus Torvalds int err; 1411da177e4SLinus Torvalds int i_mode, i_nlink, i_blksize; 1421da177e4SLinus Torvalds unsigned long long i_size; 1431da177e4SLinus Torvalds unsigned long long i_ino; 1441da177e4SLinus Torvalds unsigned long long i_blocks; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid, 1471da177e4SLinus Torvalds &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime, 1485822b7faSAlberto Bertogli &ino->i_ctime, &i_blksize, &i_blocks, -1); 1491da177e4SLinus Torvalds if (err) 150f1adc05eSJeff Dike return err; 1511da177e4SLinus Torvalds 1521da177e4SLinus Torvalds ino->i_ino = i_ino; 1531da177e4SLinus Torvalds ino->i_mode = i_mode; 1541da177e4SLinus Torvalds ino->i_nlink = i_nlink; 1551da177e4SLinus Torvalds ino->i_size = i_size; 1561da177e4SLinus Torvalds ino->i_blocks = i_blocks; 157f1adc05eSJeff Dike return 0; 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds 1601da177e4SLinus Torvalds static char *follow_link(char *link) 1611da177e4SLinus Torvalds { 1621da177e4SLinus Torvalds int len, n; 1631da177e4SLinus Torvalds char *name, *resolved, *end; 1641da177e4SLinus Torvalds 1651da177e4SLinus Torvalds len = 64; 1661da177e4SLinus Torvalds while (1) { 1671da177e4SLinus Torvalds n = -ENOMEM; 1681da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1691da177e4SLinus Torvalds if (name == NULL) 1701da177e4SLinus Torvalds goto out; 1711da177e4SLinus Torvalds 172ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1731da177e4SLinus Torvalds if (n < len) 1741da177e4SLinus Torvalds break; 1751da177e4SLinus Torvalds len *= 2; 1761da177e4SLinus Torvalds kfree(name); 1771da177e4SLinus Torvalds } 1781da177e4SLinus Torvalds if (n < 0) 1791da177e4SLinus Torvalds goto out_free; 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds if (*name == '/') 182f1adc05eSJeff Dike return name; 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds end = strrchr(link, '/'); 1851da177e4SLinus Torvalds if (end == NULL) 186f1adc05eSJeff Dike return name; 1871da177e4SLinus Torvalds 1881da177e4SLinus Torvalds *(end + 1) = '\0'; 1891da177e4SLinus Torvalds len = strlen(link) + strlen(name) + 1; 1901da177e4SLinus Torvalds 1911da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1921da177e4SLinus Torvalds if (resolved == NULL) { 1931da177e4SLinus Torvalds n = -ENOMEM; 1941da177e4SLinus Torvalds goto out_free; 1951da177e4SLinus Torvalds } 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1981da177e4SLinus Torvalds kfree(name); 1991da177e4SLinus Torvalds kfree(link); 200f1adc05eSJeff Dike return resolved; 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds out_free: 2031da177e4SLinus Torvalds kfree(name); 2041da177e4SLinus Torvalds out: 205f1adc05eSJeff Dike return ERR_PTR(n); 2061da177e4SLinus Torvalds } 2071da177e4SLinus Torvalds 2080a370e5dSDavid Howells static int hostfs_read_inode(struct inode *ino) 2091da177e4SLinus Torvalds { 2101da177e4SLinus Torvalds char *name; 2111da177e4SLinus Torvalds int err = 0; 2121da177e4SLinus Torvalds 21384b3db04SJeff Dike /* 21484b3db04SJeff Dike * Unfortunately, we are called from iget() when we don't have a dentry 2151da177e4SLinus Torvalds * allocated yet. 2161da177e4SLinus Torvalds */ 2171da177e4SLinus Torvalds if (list_empty(&ino->i_dentry)) 2181da177e4SLinus Torvalds goto out; 2191da177e4SLinus Torvalds 2201da177e4SLinus Torvalds err = -ENOMEM; 2211da177e4SLinus Torvalds name = inode_name(ino, 0); 2221da177e4SLinus Torvalds if (name == NULL) 2231da177e4SLinus Torvalds goto out; 2241da177e4SLinus Torvalds 2251da177e4SLinus Torvalds if (file_type(name, NULL, NULL) == OS_TYPE_SYMLINK) { 2261da177e4SLinus Torvalds name = follow_link(name); 2271da177e4SLinus Torvalds if (IS_ERR(name)) { 2281da177e4SLinus Torvalds err = PTR_ERR(name); 2291da177e4SLinus Torvalds goto out; 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds } 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds err = read_name(ino, name); 2341da177e4SLinus Torvalds kfree(name); 2351da177e4SLinus Torvalds out: 236f1adc05eSJeff Dike return err; 2371da177e4SLinus Torvalds } 2381da177e4SLinus Torvalds 2390a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 2400a370e5dSDavid Howells { 2410a370e5dSDavid Howells struct inode *inode; 2420a370e5dSDavid Howells long ret; 2430a370e5dSDavid Howells 2440a370e5dSDavid Howells inode = iget_locked(sb, 0); 2450a370e5dSDavid Howells if (!inode) 2460a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 2470a370e5dSDavid Howells if (inode->i_state & I_NEW) { 2480a370e5dSDavid Howells ret = hostfs_read_inode(inode); 2490a370e5dSDavid Howells if (ret < 0) { 2500a370e5dSDavid Howells iget_failed(inode); 2510a370e5dSDavid Howells return ERR_PTR(ret); 2520a370e5dSDavid Howells } 2530a370e5dSDavid Howells unlock_new_inode(inode); 2540a370e5dSDavid Howells } 2550a370e5dSDavid Howells return inode; 2560a370e5dSDavid Howells } 2570a370e5dSDavid Howells 258726c3342SDavid Howells int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 2591da177e4SLinus Torvalds { 26084b3db04SJeff Dike /* 26184b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 2621da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 2631da177e4SLinus Torvalds * so we convert them here 2641da177e4SLinus Torvalds */ 2651da177e4SLinus Torvalds int err; 2661da177e4SLinus Torvalds long long f_blocks; 2671da177e4SLinus Torvalds long long f_bfree; 2681da177e4SLinus Torvalds long long f_bavail; 2691da177e4SLinus Torvalds long long f_files; 2701da177e4SLinus Torvalds long long f_ffree; 2711da177e4SLinus Torvalds 272726c3342SDavid Howells err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, 2731da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2741da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2751da177e4SLinus Torvalds &sf->f_namelen, sf->f_spare); 276f1adc05eSJeff Dike if (err) 277f1adc05eSJeff Dike return err; 2781da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2791da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2801da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2811da177e4SLinus Torvalds sf->f_files = f_files; 2821da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2831da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 284f1adc05eSJeff Dike return 0; 2851da177e4SLinus Torvalds } 2861da177e4SLinus Torvalds 2871da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2881da177e4SLinus Torvalds { 2891da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2901da177e4SLinus Torvalds 2911da177e4SLinus Torvalds hi = kmalloc(sizeof(*hi), GFP_KERNEL); 2921da177e4SLinus Torvalds if (hi == NULL) 293f1adc05eSJeff Dike return NULL; 2941da177e4SLinus Torvalds 2951da177e4SLinus Torvalds *hi = ((struct hostfs_inode_info) { .host_filename = NULL, 2961da177e4SLinus Torvalds .fd = -1, 2971da177e4SLinus Torvalds .mode = 0 }); 2981da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 299f1adc05eSJeff Dike return &hi->vfs_inode; 3001da177e4SLinus Torvalds } 3011da177e4SLinus Torvalds 3021da177e4SLinus Torvalds static void hostfs_delete_inode(struct inode *inode) 3031da177e4SLinus Torvalds { 304fef26658SMark Fasheh truncate_inode_pages(&inode->i_data, 0); 3051da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 3061da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 3071da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 3081da177e4SLinus Torvalds } 3091da177e4SLinus Torvalds clear_inode(inode); 3101da177e4SLinus Torvalds } 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 3131da177e4SLinus Torvalds { 3141da177e4SLinus Torvalds kfree(HOSTFS_I(inode)->host_filename); 3151da177e4SLinus Torvalds 31684b3db04SJeff Dike /* 31784b3db04SJeff Dike * XXX: This should not happen, probably. The check is here for 31884b3db04SJeff Dike * additional safety. 31984b3db04SJeff Dike */ 3201da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 3211da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 3221da177e4SLinus Torvalds printk(KERN_DEBUG "Closing host fd in .destroy_inode\n"); 3231da177e4SLinus Torvalds } 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds kfree(HOSTFS_I(inode)); 3261da177e4SLinus Torvalds } 3271da177e4SLinus Torvalds 328dd2cc4dfSMiklos Szeredi static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 329dd2cc4dfSMiklos Szeredi { 330dd2cc4dfSMiklos Szeredi struct inode *root = vfs->mnt_sb->s_root->d_inode; 331dd2cc4dfSMiklos Szeredi const char *root_path = HOSTFS_I(root)->host_filename; 332dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 333dd2cc4dfSMiklos Szeredi 334dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 335dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 336dd2cc4dfSMiklos Szeredi 337dd2cc4dfSMiklos Szeredi return 0; 338dd2cc4dfSMiklos Szeredi } 339dd2cc4dfSMiklos Szeredi 340ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 3411da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 3421da177e4SLinus Torvalds .drop_inode = generic_delete_inode, 3431da177e4SLinus Torvalds .delete_inode = hostfs_delete_inode, 3441da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 3451da177e4SLinus Torvalds .statfs = hostfs_statfs, 346dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 3471da177e4SLinus Torvalds }; 3481da177e4SLinus Torvalds 3491da177e4SLinus Torvalds int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) 3501da177e4SLinus Torvalds { 3511da177e4SLinus Torvalds void *dir; 3521da177e4SLinus Torvalds char *name; 3531da177e4SLinus Torvalds unsigned long long next, ino; 3541da177e4SLinus Torvalds int error, len; 3551da177e4SLinus Torvalds 356680b0da9SJosef Sipek name = dentry_name(file->f_path.dentry, 0); 357f1adc05eSJeff Dike if (name == NULL) 358f1adc05eSJeff Dike return -ENOMEM; 3591da177e4SLinus Torvalds dir = open_dir(name, &error); 3601da177e4SLinus Torvalds kfree(name); 361f1adc05eSJeff Dike if (dir == NULL) 362f1adc05eSJeff Dike return -error; 3631da177e4SLinus Torvalds next = file->f_pos; 3641da177e4SLinus Torvalds while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { 3651da177e4SLinus Torvalds error = (*filldir)(ent, name, len, file->f_pos, 3661da177e4SLinus Torvalds ino, DT_UNKNOWN); 3671da177e4SLinus Torvalds if (error) break; 3681da177e4SLinus Torvalds file->f_pos = next; 3691da177e4SLinus Torvalds } 3701da177e4SLinus Torvalds close_dir(dir); 371f1adc05eSJeff Dike return 0; 3721da177e4SLinus Torvalds } 3731da177e4SLinus Torvalds 3741da177e4SLinus Torvalds int hostfs_file_open(struct inode *ino, struct file *file) 3751da177e4SLinus Torvalds { 3761da177e4SLinus Torvalds char *name; 377aeb5d727SAl Viro fmode_t mode = 0; 378aeb5d727SAl Viro int r = 0, w = 0, fd; 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3811da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 382f1adc05eSJeff Dike return 0; 3831da177e4SLinus Torvalds 38484b3db04SJeff Dike /* 38584b3db04SJeff Dike * The file may already have been opened, but with the wrong access, 3861da177e4SLinus Torvalds * so this resets things and reopens the file with the new access. 3871da177e4SLinus Torvalds */ 3881da177e4SLinus Torvalds if (HOSTFS_I(ino)->fd != -1) { 3891da177e4SLinus Torvalds close_file(&HOSTFS_I(ino)->fd); 3901da177e4SLinus Torvalds HOSTFS_I(ino)->fd = -1; 3911da177e4SLinus Torvalds } 3921da177e4SLinus Torvalds 3931da177e4SLinus Torvalds HOSTFS_I(ino)->mode |= mode; 3941da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_READ) 3951da177e4SLinus Torvalds r = 1; 3961da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_WRITE) 3971da177e4SLinus Torvalds w = 1; 3981da177e4SLinus Torvalds if (w) 3991da177e4SLinus Torvalds r = 1; 4001da177e4SLinus Torvalds 401680b0da9SJosef Sipek name = dentry_name(file->f_path.dentry, 0); 4021da177e4SLinus Torvalds if (name == NULL) 403f1adc05eSJeff Dike return -ENOMEM; 4041da177e4SLinus Torvalds 4051da177e4SLinus Torvalds fd = open_file(name, r, w, append); 4061da177e4SLinus Torvalds kfree(name); 407f1adc05eSJeff Dike if (fd < 0) 408f1adc05eSJeff Dike return fd; 4091da177e4SLinus Torvalds FILE_HOSTFS_I(file)->fd = fd; 4101da177e4SLinus Torvalds 411f1adc05eSJeff Dike return 0; 4121da177e4SLinus Torvalds } 4131da177e4SLinus Torvalds 4141da177e4SLinus Torvalds int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync) 4151da177e4SLinus Torvalds { 416a2d76bd8SPaolo 'Blaisorblade' Giarrusso return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync); 4171da177e4SLinus Torvalds } 4181da177e4SLinus Torvalds 4194b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 4201da177e4SLinus Torvalds .llseek = generic_file_llseek, 421543ade1fSBadari Pulavarty .read = do_sync_read, 4225ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 4231da177e4SLinus Torvalds .aio_read = generic_file_aio_read, 4241da177e4SLinus Torvalds .aio_write = generic_file_aio_write, 425543ade1fSBadari Pulavarty .write = do_sync_write, 4261da177e4SLinus Torvalds .mmap = generic_file_mmap, 4271da177e4SLinus Torvalds .open = hostfs_file_open, 4281da177e4SLinus Torvalds .release = NULL, 4291da177e4SLinus Torvalds .fsync = hostfs_fsync, 4301da177e4SLinus Torvalds }; 4311da177e4SLinus Torvalds 4324b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 4331da177e4SLinus Torvalds .llseek = generic_file_llseek, 4341da177e4SLinus Torvalds .readdir = hostfs_readdir, 4351da177e4SLinus Torvalds .read = generic_read_dir, 4361da177e4SLinus Torvalds }; 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds int hostfs_writepage(struct page *page, struct writeback_control *wbc) 4391da177e4SLinus Torvalds { 4401da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 4411da177e4SLinus Torvalds struct inode *inode = mapping->host; 4421da177e4SLinus Torvalds char *buffer; 4431da177e4SLinus Torvalds unsigned long long base; 4441da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 4451da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 4461da177e4SLinus Torvalds int err; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds if (page->index >= end_index) 4491da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds buffer = kmap(page); 4521da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4551da177e4SLinus Torvalds if (err != count) { 4561da177e4SLinus Torvalds ClearPageUptodate(page); 4571da177e4SLinus Torvalds goto out; 4581da177e4SLinus Torvalds } 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds if (base > inode->i_size) 4611da177e4SLinus Torvalds inode->i_size = base; 4621da177e4SLinus Torvalds 4631da177e4SLinus Torvalds if (PageError(page)) 4641da177e4SLinus Torvalds ClearPageError(page); 4651da177e4SLinus Torvalds err = 0; 4661da177e4SLinus Torvalds 4671da177e4SLinus Torvalds out: 4681da177e4SLinus Torvalds kunmap(page); 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds unlock_page(page); 4711da177e4SLinus Torvalds return err; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds 4741da177e4SLinus Torvalds int hostfs_readpage(struct file *file, struct page *page) 4751da177e4SLinus Torvalds { 4761da177e4SLinus Torvalds char *buffer; 4771da177e4SLinus Torvalds long long start; 4781da177e4SLinus Torvalds int err = 0; 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4811da177e4SLinus Torvalds buffer = kmap(page); 4821da177e4SLinus Torvalds err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4831da177e4SLinus Torvalds PAGE_CACHE_SIZE); 48484b3db04SJeff Dike if (err < 0) 48584b3db04SJeff Dike goto out; 4861da177e4SLinus Torvalds 4871da177e4SLinus Torvalds memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds flush_dcache_page(page); 4901da177e4SLinus Torvalds SetPageUptodate(page); 4911da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 4921da177e4SLinus Torvalds err = 0; 4931da177e4SLinus Torvalds out: 4941da177e4SLinus Torvalds kunmap(page); 4951da177e4SLinus Torvalds unlock_page(page); 496f1adc05eSJeff Dike return err; 4971da177e4SLinus Torvalds } 4981da177e4SLinus Torvalds 499ae361ff4SNick Piggin int hostfs_write_begin(struct file *file, struct address_space *mapping, 500ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 501ae361ff4SNick Piggin struct page **pagep, void **fsdata) 5021da177e4SLinus Torvalds { 503ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 504ae361ff4SNick Piggin 50554566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 506ae361ff4SNick Piggin if (!*pagep) 507ae361ff4SNick Piggin return -ENOMEM; 508ae361ff4SNick Piggin return 0; 509ae361ff4SNick Piggin } 510ae361ff4SNick Piggin 511ae361ff4SNick Piggin int hostfs_write_end(struct file *file, struct address_space *mapping, 512ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 513ae361ff4SNick Piggin struct page *page, void *fsdata) 514ae361ff4SNick Piggin { 515ae361ff4SNick Piggin struct inode *inode = mapping->host; 516ae361ff4SNick Piggin void *buffer; 517ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 5181da177e4SLinus Torvalds int err; 5191da177e4SLinus Torvalds 5201da177e4SLinus Torvalds buffer = kmap(page); 521ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 5221da177e4SLinus Torvalds kunmap(page); 5231da177e4SLinus Torvalds 524ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 525ae361ff4SNick Piggin SetPageUptodate(page); 5261da177e4SLinus Torvalds 52784b3db04SJeff Dike /* 52884b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 529ae361ff4SNick Piggin * i_size against the last byte written. 530ae361ff4SNick Piggin */ 531ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 532ae361ff4SNick Piggin inode->i_size = pos; 533ae361ff4SNick Piggin unlock_page(page); 534ae361ff4SNick Piggin page_cache_release(page); 53530f04a4eSPaolo 'Blaisorblade' Giarrusso 536f1adc05eSJeff Dike return err; 5371da177e4SLinus Torvalds } 5381da177e4SLinus Torvalds 539f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 5401da177e4SLinus Torvalds .writepage = hostfs_writepage, 5411da177e4SLinus Torvalds .readpage = hostfs_readpage, 542ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 543ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 544ae361ff4SNick Piggin .write_end = hostfs_write_end, 5451da177e4SLinus Torvalds }; 5461da177e4SLinus Torvalds 5471da177e4SLinus Torvalds static int init_inode(struct inode *inode, struct dentry *dentry) 5481da177e4SLinus Torvalds { 5491da177e4SLinus Torvalds char *name; 5501da177e4SLinus Torvalds int type, err = -ENOMEM; 5511da177e4SLinus Torvalds int maj, min; 5521da177e4SLinus Torvalds dev_t rdev = 0; 5531da177e4SLinus Torvalds 5541da177e4SLinus Torvalds if (dentry) { 5551da177e4SLinus Torvalds name = dentry_name(dentry, 0); 5561da177e4SLinus Torvalds if (name == NULL) 5571da177e4SLinus Torvalds goto out; 5581da177e4SLinus Torvalds type = file_type(name, &maj, &min); 5591da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 5601da177e4SLinus Torvalds rdev = MKDEV(maj, min); 5611da177e4SLinus Torvalds kfree(name); 5621da177e4SLinus Torvalds } 5631da177e4SLinus Torvalds else type = OS_TYPE_DIR; 5641da177e4SLinus Torvalds 5651da177e4SLinus Torvalds err = 0; 5661da177e4SLinus Torvalds if (type == OS_TYPE_SYMLINK) 5671da177e4SLinus Torvalds inode->i_op = &page_symlink_inode_operations; 5681da177e4SLinus Torvalds else if (type == OS_TYPE_DIR) 5691da177e4SLinus Torvalds inode->i_op = &hostfs_dir_iops; 5701da177e4SLinus Torvalds else inode->i_op = &hostfs_iops; 5711da177e4SLinus Torvalds 5721da177e4SLinus Torvalds if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; 5731da177e4SLinus Torvalds else inode->i_fop = &hostfs_file_fops; 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds if (type == OS_TYPE_SYMLINK) 5761da177e4SLinus Torvalds inode->i_mapping->a_ops = &hostfs_link_aops; 5771da177e4SLinus Torvalds else inode->i_mapping->a_ops = &hostfs_aops; 5781da177e4SLinus Torvalds 5791da177e4SLinus Torvalds switch (type) { 5801da177e4SLinus Torvalds case OS_TYPE_CHARDEV: 5811da177e4SLinus Torvalds init_special_inode(inode, S_IFCHR, rdev); 5821da177e4SLinus Torvalds break; 5831da177e4SLinus Torvalds case OS_TYPE_BLOCKDEV: 5841da177e4SLinus Torvalds init_special_inode(inode, S_IFBLK, rdev); 5851da177e4SLinus Torvalds break; 5861da177e4SLinus Torvalds case OS_TYPE_FIFO: 5871da177e4SLinus Torvalds init_special_inode(inode, S_IFIFO, 0); 5881da177e4SLinus Torvalds break; 5891da177e4SLinus Torvalds case OS_TYPE_SOCK: 5901da177e4SLinus Torvalds init_special_inode(inode, S_IFSOCK, 0); 5911da177e4SLinus Torvalds break; 5921da177e4SLinus Torvalds } 5931da177e4SLinus Torvalds out: 594f1adc05eSJeff Dike return err; 5951da177e4SLinus Torvalds } 5961da177e4SLinus Torvalds 5971da177e4SLinus Torvalds int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, 5981da177e4SLinus Torvalds struct nameidata *nd) 5991da177e4SLinus Torvalds { 6001da177e4SLinus Torvalds struct inode *inode; 6011da177e4SLinus Torvalds char *name; 6021da177e4SLinus Torvalds int error, fd; 6031da177e4SLinus Torvalds 6040a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 6050a370e5dSDavid Howells if (IS_ERR(inode)) { 6060a370e5dSDavid Howells error = PTR_ERR(inode); 60784b3db04SJeff Dike goto out; 6080a370e5dSDavid Howells } 6091da177e4SLinus Torvalds 6101da177e4SLinus Torvalds error = init_inode(inode, dentry); 6111da177e4SLinus Torvalds if (error) 6121da177e4SLinus Torvalds goto out_put; 6131da177e4SLinus Torvalds 6141da177e4SLinus Torvalds error = -ENOMEM; 6151da177e4SLinus Torvalds name = dentry_name(dentry, 0); 6161da177e4SLinus Torvalds if (name == NULL) 6171da177e4SLinus Torvalds goto out_put; 6181da177e4SLinus Torvalds 6191da177e4SLinus Torvalds fd = file_create(name, 6201da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 6211da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 6221da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 6231da177e4SLinus Torvalds if (fd < 0) 6241da177e4SLinus Torvalds error = fd; 6251da177e4SLinus Torvalds else error = read_name(inode, name); 6261da177e4SLinus Torvalds 6271da177e4SLinus Torvalds kfree(name); 6281da177e4SLinus Torvalds if (error) 6291da177e4SLinus Torvalds goto out_put; 6301da177e4SLinus Torvalds 6311da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 6321da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 6331da177e4SLinus Torvalds d_instantiate(dentry, inode); 634f1adc05eSJeff Dike return 0; 6351da177e4SLinus Torvalds 6361da177e4SLinus Torvalds out_put: 6371da177e4SLinus Torvalds iput(inode); 6381da177e4SLinus Torvalds out: 639f1adc05eSJeff Dike return error; 6401da177e4SLinus Torvalds } 6411da177e4SLinus Torvalds 6421da177e4SLinus Torvalds struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 6431da177e4SLinus Torvalds struct nameidata *nd) 6441da177e4SLinus Torvalds { 6451da177e4SLinus Torvalds struct inode *inode; 6461da177e4SLinus Torvalds char *name; 6471da177e4SLinus Torvalds int err; 6481da177e4SLinus Torvalds 6490a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 6500a370e5dSDavid Howells if (IS_ERR(inode)) { 6510a370e5dSDavid Howells err = PTR_ERR(inode); 6521da177e4SLinus Torvalds goto out; 6530a370e5dSDavid Howells } 6541da177e4SLinus Torvalds 6551da177e4SLinus Torvalds err = init_inode(inode, dentry); 6561da177e4SLinus Torvalds if (err) 6571da177e4SLinus Torvalds goto out_put; 6581da177e4SLinus Torvalds 6591da177e4SLinus Torvalds err = -ENOMEM; 6601da177e4SLinus Torvalds name = dentry_name(dentry, 0); 6611da177e4SLinus Torvalds if (name == NULL) 6621da177e4SLinus Torvalds goto out_put; 6631da177e4SLinus Torvalds 6641da177e4SLinus Torvalds err = read_name(inode, name); 6651da177e4SLinus Torvalds kfree(name); 6661da177e4SLinus Torvalds if (err == -ENOENT) { 6671da177e4SLinus Torvalds iput(inode); 6681da177e4SLinus Torvalds inode = NULL; 6691da177e4SLinus Torvalds } 6701da177e4SLinus Torvalds else if (err) 6711da177e4SLinus Torvalds goto out_put; 6721da177e4SLinus Torvalds 6731da177e4SLinus Torvalds d_add(dentry, inode); 6741da177e4SLinus Torvalds dentry->d_op = &hostfs_dentry_ops; 675f1adc05eSJeff Dike return NULL; 6761da177e4SLinus Torvalds 6771da177e4SLinus Torvalds out_put: 6781da177e4SLinus Torvalds iput(inode); 6791da177e4SLinus Torvalds out: 680f1adc05eSJeff Dike return ERR_PTR(err); 6811da177e4SLinus Torvalds } 6821da177e4SLinus Torvalds 6831da177e4SLinus Torvalds static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) 6841da177e4SLinus Torvalds { 6851da177e4SLinus Torvalds char *file; 6861da177e4SLinus Torvalds int len; 6871da177e4SLinus Torvalds 6881da177e4SLinus Torvalds file = inode_name(ino, dentry->d_name.len + 1); 689f1adc05eSJeff Dike if (file == NULL) 690f1adc05eSJeff Dike return NULL; 6911da177e4SLinus Torvalds strcat(file, "/"); 6921da177e4SLinus Torvalds len = strlen(file); 6931da177e4SLinus Torvalds strncat(file, dentry->d_name.name, dentry->d_name.len); 6941da177e4SLinus Torvalds file[len + dentry->d_name.len] = '\0'; 695f1adc05eSJeff Dike return file; 6961da177e4SLinus Torvalds } 6971da177e4SLinus Torvalds 6981da177e4SLinus Torvalds int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) 6991da177e4SLinus Torvalds { 7001da177e4SLinus Torvalds char *from_name, *to_name; 7011da177e4SLinus Torvalds int err; 7021da177e4SLinus Torvalds 7031da177e4SLinus Torvalds if ((from_name = inode_dentry_name(ino, from)) == NULL) 704f1adc05eSJeff Dike return -ENOMEM; 7051da177e4SLinus Torvalds to_name = dentry_name(to, 0); 7061da177e4SLinus Torvalds if (to_name == NULL) { 7071da177e4SLinus Torvalds kfree(from_name); 708f1adc05eSJeff Dike return -ENOMEM; 7091da177e4SLinus Torvalds } 7101da177e4SLinus Torvalds err = link_file(to_name, from_name); 7111da177e4SLinus Torvalds kfree(from_name); 7121da177e4SLinus Torvalds kfree(to_name); 713f1adc05eSJeff Dike return err; 7141da177e4SLinus Torvalds } 7151da177e4SLinus Torvalds 7161da177e4SLinus Torvalds int hostfs_unlink(struct inode *ino, struct dentry *dentry) 7171da177e4SLinus Torvalds { 7181da177e4SLinus Torvalds char *file; 7191da177e4SLinus Torvalds int err; 7201da177e4SLinus Torvalds 721f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 722f1adc05eSJeff Dike return -ENOMEM; 7231da177e4SLinus Torvalds if (append) 724f1adc05eSJeff Dike return -EPERM; 7251da177e4SLinus Torvalds 7261da177e4SLinus Torvalds err = unlink_file(file); 7271da177e4SLinus Torvalds kfree(file); 728f1adc05eSJeff Dike return err; 7291da177e4SLinus Torvalds } 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) 7321da177e4SLinus Torvalds { 7331da177e4SLinus Torvalds char *file; 7341da177e4SLinus Torvalds int err; 7351da177e4SLinus Torvalds 736f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 737f1adc05eSJeff Dike return -ENOMEM; 7381da177e4SLinus Torvalds err = make_symlink(file, to); 7391da177e4SLinus Torvalds kfree(file); 740f1adc05eSJeff Dike return err; 7411da177e4SLinus Torvalds } 7421da177e4SLinus Torvalds 7431da177e4SLinus Torvalds int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) 7441da177e4SLinus Torvalds { 7451da177e4SLinus Torvalds char *file; 7461da177e4SLinus Torvalds int err; 7471da177e4SLinus Torvalds 748f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 749f1adc05eSJeff Dike return -ENOMEM; 7501da177e4SLinus Torvalds err = do_mkdir(file, mode); 7511da177e4SLinus Torvalds kfree(file); 752f1adc05eSJeff Dike return err; 7531da177e4SLinus Torvalds } 7541da177e4SLinus Torvalds 7551da177e4SLinus Torvalds int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 7561da177e4SLinus Torvalds { 7571da177e4SLinus Torvalds char *file; 7581da177e4SLinus Torvalds int err; 7591da177e4SLinus Torvalds 760f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 761f1adc05eSJeff Dike return -ENOMEM; 7621da177e4SLinus Torvalds err = do_rmdir(file); 7631da177e4SLinus Torvalds kfree(file); 764f1adc05eSJeff Dike return err; 7651da177e4SLinus Torvalds } 7661da177e4SLinus Torvalds 7671da177e4SLinus Torvalds int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 7681da177e4SLinus Torvalds { 7691da177e4SLinus Torvalds struct inode *inode; 7701da177e4SLinus Torvalds char *name; 7710a370e5dSDavid Howells int err; 7721da177e4SLinus Torvalds 7730a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7740a370e5dSDavid Howells if (IS_ERR(inode)) { 7750a370e5dSDavid Howells err = PTR_ERR(inode); 7761da177e4SLinus Torvalds goto out; 7770a370e5dSDavid Howells } 7781da177e4SLinus Torvalds 7791da177e4SLinus Torvalds err = init_inode(inode, dentry); 7801da177e4SLinus Torvalds if (err) 7811da177e4SLinus Torvalds goto out_put; 7821da177e4SLinus Torvalds 7831da177e4SLinus Torvalds err = -ENOMEM; 7841da177e4SLinus Torvalds name = dentry_name(dentry, 0); 7851da177e4SLinus Torvalds if (name == NULL) 7861da177e4SLinus Torvalds goto out_put; 7871da177e4SLinus Torvalds 7881da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 78988f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 7901da177e4SLinus Torvalds if (err) 7911da177e4SLinus Torvalds goto out_free; 7921da177e4SLinus Torvalds 7931da177e4SLinus Torvalds err = read_name(inode, name); 7941da177e4SLinus Torvalds kfree(name); 7951da177e4SLinus Torvalds if (err) 7961da177e4SLinus Torvalds goto out_put; 7971da177e4SLinus Torvalds 7981da177e4SLinus Torvalds d_instantiate(dentry, inode); 799f1adc05eSJeff Dike return 0; 8001da177e4SLinus Torvalds 8011da177e4SLinus Torvalds out_free: 8021da177e4SLinus Torvalds kfree(name); 8031da177e4SLinus Torvalds out_put: 8041da177e4SLinus Torvalds iput(inode); 8051da177e4SLinus Torvalds out: 806f1adc05eSJeff Dike return err; 8071da177e4SLinus Torvalds } 8081da177e4SLinus Torvalds 8091da177e4SLinus Torvalds int hostfs_rename(struct inode *from_ino, struct dentry *from, 8101da177e4SLinus Torvalds struct inode *to_ino, struct dentry *to) 8111da177e4SLinus Torvalds { 8121da177e4SLinus Torvalds char *from_name, *to_name; 8131da177e4SLinus Torvalds int err; 8141da177e4SLinus Torvalds 8151da177e4SLinus Torvalds if ((from_name = inode_dentry_name(from_ino, from)) == NULL) 816f1adc05eSJeff Dike return -ENOMEM; 8171da177e4SLinus Torvalds if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { 8181da177e4SLinus Torvalds kfree(from_name); 819f1adc05eSJeff Dike return -ENOMEM; 8201da177e4SLinus Torvalds } 8211da177e4SLinus Torvalds err = rename_file(from_name, to_name); 8221da177e4SLinus Torvalds kfree(from_name); 8231da177e4SLinus Torvalds kfree(to_name); 824f1adc05eSJeff Dike return err; 8251da177e4SLinus Torvalds } 8261da177e4SLinus Torvalds 827e6305c43SAl Viro int hostfs_permission(struct inode *ino, int desired) 8281da177e4SLinus Torvalds { 8291da177e4SLinus Torvalds char *name; 8301da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 8311da177e4SLinus Torvalds 8321da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 8331da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 8341da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 8351da177e4SLinus Torvalds name = inode_name(ino, 0); 836f1adc05eSJeff Dike if (name == NULL) 837f1adc05eSJeff Dike return -ENOMEM; 8381da177e4SLinus Torvalds 8391da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 8401da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 8411da177e4SLinus Torvalds err = 0; 8421da177e4SLinus Torvalds else 8431da177e4SLinus Torvalds err = access_file(name, r, w, x); 8441da177e4SLinus Torvalds kfree(name); 8451da177e4SLinus Torvalds if (!err) 8461da177e4SLinus Torvalds err = generic_permission(ino, desired, NULL); 8471da177e4SLinus Torvalds return err; 8481da177e4SLinus Torvalds } 8491da177e4SLinus Torvalds 8501da177e4SLinus Torvalds int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 8511da177e4SLinus Torvalds { 8521da177e4SLinus Torvalds struct hostfs_iattr attrs; 8531da177e4SLinus Torvalds char *name; 8541da177e4SLinus Torvalds int err; 8551da177e4SLinus Torvalds 8565822b7faSAlberto Bertogli int fd = HOSTFS_I(dentry->d_inode)->fd; 8575822b7faSAlberto Bertogli 8581da177e4SLinus Torvalds err = inode_change_ok(dentry->d_inode, attr); 8591da177e4SLinus Torvalds if (err) 8601da177e4SLinus Torvalds return err; 8611da177e4SLinus Torvalds 8621da177e4SLinus Torvalds if (append) 8631da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 8641da177e4SLinus Torvalds 8651da177e4SLinus Torvalds attrs.ia_valid = 0; 8661da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 8671da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 8681da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 8691da177e4SLinus Torvalds } 8701da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8711da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 8721da177e4SLinus Torvalds attrs.ia_uid = attr->ia_uid; 8731da177e4SLinus Torvalds } 8741da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8751da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 8761da177e4SLinus Torvalds attrs.ia_gid = attr->ia_gid; 8771da177e4SLinus Torvalds } 8781da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8791da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8801da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8811da177e4SLinus Torvalds } 8821da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8831da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 8841da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 8851da177e4SLinus Torvalds } 8861da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8871da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 8881da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 8891da177e4SLinus Torvalds } 8901da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8911da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 8921da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 8931da177e4SLinus Torvalds } 8941da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8951da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8961da177e4SLinus Torvalds } 8971da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8981da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8991da177e4SLinus Torvalds } 9001da177e4SLinus Torvalds name = dentry_name(dentry, 0); 901f1adc05eSJeff Dike if (name == NULL) 902f1adc05eSJeff Dike return -ENOMEM; 9035822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 9041da177e4SLinus Torvalds kfree(name); 9051da177e4SLinus Torvalds if (err) 906f1adc05eSJeff Dike return err; 9071da177e4SLinus Torvalds 908f1adc05eSJeff Dike return inode_setattr(dentry->d_inode, attr); 9091da177e4SLinus Torvalds } 9101da177e4SLinus Torvalds 91192e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 9121da177e4SLinus Torvalds .create = hostfs_create, 9131da177e4SLinus Torvalds .link = hostfs_link, 9141da177e4SLinus Torvalds .unlink = hostfs_unlink, 9151da177e4SLinus Torvalds .symlink = hostfs_symlink, 9161da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 9171da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 9181da177e4SLinus Torvalds .mknod = hostfs_mknod, 9191da177e4SLinus Torvalds .rename = hostfs_rename, 9201da177e4SLinus Torvalds .permission = hostfs_permission, 9211da177e4SLinus Torvalds .setattr = hostfs_setattr, 9221da177e4SLinus Torvalds }; 9231da177e4SLinus Torvalds 92492e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 9251da177e4SLinus Torvalds .create = hostfs_create, 9261da177e4SLinus Torvalds .lookup = hostfs_lookup, 9271da177e4SLinus Torvalds .link = hostfs_link, 9281da177e4SLinus Torvalds .unlink = hostfs_unlink, 9291da177e4SLinus Torvalds .symlink = hostfs_symlink, 9301da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 9311da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 9321da177e4SLinus Torvalds .mknod = hostfs_mknod, 9331da177e4SLinus Torvalds .rename = hostfs_rename, 9341da177e4SLinus Torvalds .permission = hostfs_permission, 9351da177e4SLinus Torvalds .setattr = hostfs_setattr, 9361da177e4SLinus Torvalds }; 9371da177e4SLinus Torvalds 9381da177e4SLinus Torvalds int hostfs_link_readpage(struct file *file, struct page *page) 9391da177e4SLinus Torvalds { 9401da177e4SLinus Torvalds char *buffer, *name; 9411da177e4SLinus Torvalds int err; 9421da177e4SLinus Torvalds 9431da177e4SLinus Torvalds buffer = kmap(page); 9441da177e4SLinus Torvalds name = inode_name(page->mapping->host, 0); 945f1adc05eSJeff Dike if (name == NULL) 946f1adc05eSJeff Dike return -ENOMEM; 947ea7e743eSWANG Cong err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); 9481da177e4SLinus Torvalds kfree(name); 9491da177e4SLinus Torvalds if (err == PAGE_CACHE_SIZE) 9501da177e4SLinus Torvalds err = -E2BIG; 9511da177e4SLinus Torvalds else if (err > 0) { 9521da177e4SLinus Torvalds flush_dcache_page(page); 9531da177e4SLinus Torvalds SetPageUptodate(page); 9541da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 9551da177e4SLinus Torvalds err = 0; 9561da177e4SLinus Torvalds } 9571da177e4SLinus Torvalds kunmap(page); 9581da177e4SLinus Torvalds unlock_page(page); 959f1adc05eSJeff Dike return err; 9601da177e4SLinus Torvalds } 9611da177e4SLinus Torvalds 962f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_link_aops = { 9631da177e4SLinus Torvalds .readpage = hostfs_link_readpage, 9641da177e4SLinus Torvalds }; 9651da177e4SLinus Torvalds 9661da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9671da177e4SLinus Torvalds { 9681da177e4SLinus Torvalds struct inode *root_inode; 96975e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9701da177e4SLinus Torvalds int err; 9711da177e4SLinus Torvalds 9721da177e4SLinus Torvalds sb->s_blocksize = 1024; 9731da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9741da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9751da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 976752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9771da177e4SLinus Torvalds 978a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 97975e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 98075e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9811da177e4SLinus Torvalds 9821da177e4SLinus Torvalds err = -ENOMEM; 98375e8defbSPaolo 'Blaisorblade' Giarrusso host_root_path = kmalloc(strlen(root_ino) + 1 98475e8defbSPaolo 'Blaisorblade' Giarrusso + strlen(req_root) + 1, GFP_KERNEL); 98575e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9861da177e4SLinus Torvalds goto out; 9871da177e4SLinus Torvalds 98875e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9891da177e4SLinus Torvalds 9900a370e5dSDavid Howells root_inode = hostfs_iget(sb); 9910a370e5dSDavid Howells if (IS_ERR(root_inode)) { 9920a370e5dSDavid Howells err = PTR_ERR(root_inode); 9931da177e4SLinus Torvalds goto out_free; 9940a370e5dSDavid Howells } 9951da177e4SLinus Torvalds 9961da177e4SLinus Torvalds err = init_inode(root_inode, NULL); 9971da177e4SLinus Torvalds if (err) 9981da177e4SLinus Torvalds goto out_put; 9991da177e4SLinus Torvalds 100075e8defbSPaolo 'Blaisorblade' Giarrusso HOSTFS_I(root_inode)->host_filename = host_root_path; 100184b3db04SJeff Dike /* 100284b3db04SJeff Dike * Avoid that in the error path, iput(root_inode) frees again 100384b3db04SJeff Dike * host_root_path through hostfs_destroy_inode! 100484b3db04SJeff Dike */ 100575e8defbSPaolo 'Blaisorblade' Giarrusso host_root_path = NULL; 10061da177e4SLinus Torvalds 10071da177e4SLinus Torvalds err = -ENOMEM; 10081da177e4SLinus Torvalds sb->s_root = d_alloc_root(root_inode); 10091da177e4SLinus Torvalds if (sb->s_root == NULL) 10101da177e4SLinus Torvalds goto out_put; 10111da177e4SLinus Torvalds 10120a370e5dSDavid Howells err = hostfs_read_inode(root_inode); 101351a14110SJeff Dike if (err) { 101451a14110SJeff Dike /* No iput in this case because the dput does that for us */ 101551a14110SJeff Dike dput(sb->s_root); 101651a14110SJeff Dike sb->s_root = NULL; 1017bca27113SPaolo 'Blaisorblade' Giarrusso goto out; 101851a14110SJeff Dike } 10191da177e4SLinus Torvalds 1020f1adc05eSJeff Dike return 0; 10211da177e4SLinus Torvalds 10221da177e4SLinus Torvalds out_put: 10231da177e4SLinus Torvalds iput(root_inode); 10241da177e4SLinus Torvalds out_free: 102575e8defbSPaolo 'Blaisorblade' Giarrusso kfree(host_root_path); 10261da177e4SLinus Torvalds out: 1027f1adc05eSJeff Dike return err; 10281da177e4SLinus Torvalds } 10291da177e4SLinus Torvalds 1030454e2398SDavid Howells static int hostfs_read_sb(struct file_system_type *type, 10311da177e4SLinus Torvalds int flags, const char *dev_name, 1032454e2398SDavid Howells void *data, struct vfsmount *mnt) 10331da177e4SLinus Torvalds { 1034454e2398SDavid Howells return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); 10351da177e4SLinus Torvalds } 10361da177e4SLinus Torvalds 10371da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 10381da177e4SLinus Torvalds .owner = THIS_MODULE, 10391da177e4SLinus Torvalds .name = "hostfs", 10401da177e4SLinus Torvalds .get_sb = hostfs_read_sb, 10411da177e4SLinus Torvalds .kill_sb = kill_anon_super, 10421da177e4SLinus Torvalds .fs_flags = 0, 10431da177e4SLinus Torvalds }; 10441da177e4SLinus Torvalds 10451da177e4SLinus Torvalds static int __init init_hostfs(void) 10461da177e4SLinus Torvalds { 1047f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 10481da177e4SLinus Torvalds } 10491da177e4SLinus Torvalds 10501da177e4SLinus Torvalds static void __exit exit_hostfs(void) 10511da177e4SLinus Torvalds { 10521da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 10531da177e4SLinus Torvalds } 10541da177e4SLinus Torvalds 10551da177e4SLinus Torvalds module_init(init_hostfs) 10561da177e4SLinus Torvalds module_exit(exit_hostfs) 10571da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1058