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 244e971a6d7SAl Viro inode = new_inode(sb); 2450a370e5dSDavid Howells if (!inode) 2460a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 2470a370e5dSDavid Howells ret = hostfs_read_inode(inode); 2480a370e5dSDavid Howells if (ret < 0) { 249e971a6d7SAl Viro iput(inode); 2500a370e5dSDavid Howells return ERR_PTR(ret); 2510a370e5dSDavid Howells } 2520a370e5dSDavid Howells return inode; 2530a370e5dSDavid Howells } 2540a370e5dSDavid Howells 255726c3342SDavid Howells int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 2561da177e4SLinus Torvalds { 25784b3db04SJeff Dike /* 25884b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 2591da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 2601da177e4SLinus Torvalds * so we convert them here 2611da177e4SLinus Torvalds */ 2621da177e4SLinus Torvalds int err; 2631da177e4SLinus Torvalds long long f_blocks; 2641da177e4SLinus Torvalds long long f_bfree; 2651da177e4SLinus Torvalds long long f_bavail; 2661da177e4SLinus Torvalds long long f_files; 2671da177e4SLinus Torvalds long long f_ffree; 2681da177e4SLinus Torvalds 269726c3342SDavid Howells err = do_statfs(HOSTFS_I(dentry->d_sb->s_root->d_inode)->host_filename, 2701da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2711da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2721da177e4SLinus Torvalds &sf->f_namelen, sf->f_spare); 273f1adc05eSJeff Dike if (err) 274f1adc05eSJeff Dike return err; 2751da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2761da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2771da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2781da177e4SLinus Torvalds sf->f_files = f_files; 2791da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2801da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 281f1adc05eSJeff Dike return 0; 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 2841da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2851da177e4SLinus Torvalds { 2861da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2871da177e4SLinus Torvalds 2881da177e4SLinus Torvalds hi = kmalloc(sizeof(*hi), GFP_KERNEL); 2891da177e4SLinus Torvalds if (hi == NULL) 290f1adc05eSJeff Dike return NULL; 2911da177e4SLinus Torvalds 2921da177e4SLinus Torvalds *hi = ((struct hostfs_inode_info) { .host_filename = NULL, 2931da177e4SLinus Torvalds .fd = -1, 2941da177e4SLinus Torvalds .mode = 0 }); 2951da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 296f1adc05eSJeff Dike return &hi->vfs_inode; 2971da177e4SLinus Torvalds } 2981da177e4SLinus Torvalds 299e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 3001da177e4SLinus Torvalds { 301fef26658SMark Fasheh truncate_inode_pages(&inode->i_data, 0); 302e971a6d7SAl Viro end_writeback(inode); 3031da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 3041da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 3051da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 3061da177e4SLinus Torvalds } 3071da177e4SLinus Torvalds } 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 3101da177e4SLinus Torvalds { 3111da177e4SLinus Torvalds kfree(HOSTFS_I(inode)->host_filename); 3121da177e4SLinus Torvalds kfree(HOSTFS_I(inode)); 3131da177e4SLinus Torvalds } 3141da177e4SLinus Torvalds 315dd2cc4dfSMiklos Szeredi static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 316dd2cc4dfSMiklos Szeredi { 317dd2cc4dfSMiklos Szeredi struct inode *root = vfs->mnt_sb->s_root->d_inode; 318dd2cc4dfSMiklos Szeredi const char *root_path = HOSTFS_I(root)->host_filename; 319dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 320dd2cc4dfSMiklos Szeredi 321dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 322dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 323dd2cc4dfSMiklos Szeredi 324dd2cc4dfSMiklos Szeredi return 0; 325dd2cc4dfSMiklos Szeredi } 326dd2cc4dfSMiklos Szeredi 327ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 3281da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 3291da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 330e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 3311da177e4SLinus Torvalds .statfs = hostfs_statfs, 332dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 3331da177e4SLinus Torvalds }; 3341da177e4SLinus Torvalds 3351da177e4SLinus Torvalds int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) 3361da177e4SLinus Torvalds { 3371da177e4SLinus Torvalds void *dir; 3381da177e4SLinus Torvalds char *name; 3391da177e4SLinus Torvalds unsigned long long next, ino; 3401da177e4SLinus Torvalds int error, len; 3411da177e4SLinus Torvalds 342680b0da9SJosef Sipek name = dentry_name(file->f_path.dentry, 0); 343f1adc05eSJeff Dike if (name == NULL) 344f1adc05eSJeff Dike return -ENOMEM; 3451da177e4SLinus Torvalds dir = open_dir(name, &error); 3461da177e4SLinus Torvalds kfree(name); 347f1adc05eSJeff Dike if (dir == NULL) 348f1adc05eSJeff Dike return -error; 3491da177e4SLinus Torvalds next = file->f_pos; 3501da177e4SLinus Torvalds while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { 3511da177e4SLinus Torvalds error = (*filldir)(ent, name, len, file->f_pos, 3521da177e4SLinus Torvalds ino, DT_UNKNOWN); 3531da177e4SLinus Torvalds if (error) break; 3541da177e4SLinus Torvalds file->f_pos = next; 3551da177e4SLinus Torvalds } 3561da177e4SLinus Torvalds close_dir(dir); 357f1adc05eSJeff Dike return 0; 3581da177e4SLinus Torvalds } 3591da177e4SLinus Torvalds 3601da177e4SLinus Torvalds int hostfs_file_open(struct inode *ino, struct file *file) 3611da177e4SLinus Torvalds { 3621da177e4SLinus Torvalds char *name; 363aeb5d727SAl Viro fmode_t mode = 0; 364aeb5d727SAl Viro int r = 0, w = 0, fd; 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3671da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 368f1adc05eSJeff Dike return 0; 3691da177e4SLinus Torvalds 37084b3db04SJeff Dike /* 37184b3db04SJeff Dike * The file may already have been opened, but with the wrong access, 3721da177e4SLinus Torvalds * so this resets things and reopens the file with the new access. 3731da177e4SLinus Torvalds */ 3741da177e4SLinus Torvalds if (HOSTFS_I(ino)->fd != -1) { 3751da177e4SLinus Torvalds close_file(&HOSTFS_I(ino)->fd); 3761da177e4SLinus Torvalds HOSTFS_I(ino)->fd = -1; 3771da177e4SLinus Torvalds } 3781da177e4SLinus Torvalds 3791da177e4SLinus Torvalds HOSTFS_I(ino)->mode |= mode; 3801da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_READ) 3811da177e4SLinus Torvalds r = 1; 3821da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_WRITE) 3831da177e4SLinus Torvalds w = 1; 3841da177e4SLinus Torvalds if (w) 3851da177e4SLinus Torvalds r = 1; 3861da177e4SLinus Torvalds 387680b0da9SJosef Sipek name = dentry_name(file->f_path.dentry, 0); 3881da177e4SLinus Torvalds if (name == NULL) 389f1adc05eSJeff Dike return -ENOMEM; 3901da177e4SLinus Torvalds 3911da177e4SLinus Torvalds fd = open_file(name, r, w, append); 3921da177e4SLinus Torvalds kfree(name); 393f1adc05eSJeff Dike if (fd < 0) 394f1adc05eSJeff Dike return fd; 3951da177e4SLinus Torvalds FILE_HOSTFS_I(file)->fd = fd; 3961da177e4SLinus Torvalds 397f1adc05eSJeff Dike return 0; 3981da177e4SLinus Torvalds } 3991da177e4SLinus Torvalds 4007ea80859SChristoph Hellwig int hostfs_fsync(struct file *file, int datasync) 4011da177e4SLinus Torvalds { 4027ea80859SChristoph Hellwig return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); 4031da177e4SLinus Torvalds } 4041da177e4SLinus Torvalds 4054b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 4061da177e4SLinus Torvalds .llseek = generic_file_llseek, 407543ade1fSBadari Pulavarty .read = do_sync_read, 4085ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 4091da177e4SLinus Torvalds .aio_read = generic_file_aio_read, 4101da177e4SLinus Torvalds .aio_write = generic_file_aio_write, 411543ade1fSBadari Pulavarty .write = do_sync_write, 4121da177e4SLinus Torvalds .mmap = generic_file_mmap, 4131da177e4SLinus Torvalds .open = hostfs_file_open, 4141da177e4SLinus Torvalds .release = NULL, 4151da177e4SLinus Torvalds .fsync = hostfs_fsync, 4161da177e4SLinus Torvalds }; 4171da177e4SLinus Torvalds 4184b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 4191da177e4SLinus Torvalds .llseek = generic_file_llseek, 4201da177e4SLinus Torvalds .readdir = hostfs_readdir, 4211da177e4SLinus Torvalds .read = generic_read_dir, 4221da177e4SLinus Torvalds }; 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds int hostfs_writepage(struct page *page, struct writeback_control *wbc) 4251da177e4SLinus Torvalds { 4261da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 4271da177e4SLinus Torvalds struct inode *inode = mapping->host; 4281da177e4SLinus Torvalds char *buffer; 4291da177e4SLinus Torvalds unsigned long long base; 4301da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 4311da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 4321da177e4SLinus Torvalds int err; 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds if (page->index >= end_index) 4351da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 4361da177e4SLinus Torvalds 4371da177e4SLinus Torvalds buffer = kmap(page); 4381da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 4411da177e4SLinus Torvalds if (err != count) { 4421da177e4SLinus Torvalds ClearPageUptodate(page); 4431da177e4SLinus Torvalds goto out; 4441da177e4SLinus Torvalds } 4451da177e4SLinus Torvalds 4461da177e4SLinus Torvalds if (base > inode->i_size) 4471da177e4SLinus Torvalds inode->i_size = base; 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds if (PageError(page)) 4501da177e4SLinus Torvalds ClearPageError(page); 4511da177e4SLinus Torvalds err = 0; 4521da177e4SLinus Torvalds 4531da177e4SLinus Torvalds out: 4541da177e4SLinus Torvalds kunmap(page); 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds unlock_page(page); 4571da177e4SLinus Torvalds return err; 4581da177e4SLinus Torvalds } 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds int hostfs_readpage(struct file *file, struct page *page) 4611da177e4SLinus Torvalds { 4621da177e4SLinus Torvalds char *buffer; 4631da177e4SLinus Torvalds long long start; 4641da177e4SLinus Torvalds int err = 0; 4651da177e4SLinus Torvalds 4661da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4671da177e4SLinus Torvalds buffer = kmap(page); 4681da177e4SLinus Torvalds err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4691da177e4SLinus Torvalds PAGE_CACHE_SIZE); 47084b3db04SJeff Dike if (err < 0) 47184b3db04SJeff Dike goto out; 4721da177e4SLinus Torvalds 4731da177e4SLinus Torvalds memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); 4741da177e4SLinus Torvalds 4751da177e4SLinus Torvalds flush_dcache_page(page); 4761da177e4SLinus Torvalds SetPageUptodate(page); 4771da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 4781da177e4SLinus Torvalds err = 0; 4791da177e4SLinus Torvalds out: 4801da177e4SLinus Torvalds kunmap(page); 4811da177e4SLinus Torvalds unlock_page(page); 482f1adc05eSJeff Dike return err; 4831da177e4SLinus Torvalds } 4841da177e4SLinus Torvalds 485ae361ff4SNick Piggin int hostfs_write_begin(struct file *file, struct address_space *mapping, 486ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 487ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4881da177e4SLinus Torvalds { 489ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 490ae361ff4SNick Piggin 49154566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 492ae361ff4SNick Piggin if (!*pagep) 493ae361ff4SNick Piggin return -ENOMEM; 494ae361ff4SNick Piggin return 0; 495ae361ff4SNick Piggin } 496ae361ff4SNick Piggin 497ae361ff4SNick Piggin int hostfs_write_end(struct file *file, struct address_space *mapping, 498ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 499ae361ff4SNick Piggin struct page *page, void *fsdata) 500ae361ff4SNick Piggin { 501ae361ff4SNick Piggin struct inode *inode = mapping->host; 502ae361ff4SNick Piggin void *buffer; 503ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 5041da177e4SLinus Torvalds int err; 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds buffer = kmap(page); 507ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 5081da177e4SLinus Torvalds kunmap(page); 5091da177e4SLinus Torvalds 510ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 511ae361ff4SNick Piggin SetPageUptodate(page); 5121da177e4SLinus Torvalds 51384b3db04SJeff Dike /* 51484b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 515ae361ff4SNick Piggin * i_size against the last byte written. 516ae361ff4SNick Piggin */ 517ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 518ae361ff4SNick Piggin inode->i_size = pos; 519ae361ff4SNick Piggin unlock_page(page); 520ae361ff4SNick Piggin page_cache_release(page); 52130f04a4eSPaolo 'Blaisorblade' Giarrusso 522f1adc05eSJeff Dike return err; 5231da177e4SLinus Torvalds } 5241da177e4SLinus Torvalds 525f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 5261da177e4SLinus Torvalds .writepage = hostfs_writepage, 5271da177e4SLinus Torvalds .readpage = hostfs_readpage, 528ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 529ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 530ae361ff4SNick Piggin .write_end = hostfs_write_end, 5311da177e4SLinus Torvalds }; 5321da177e4SLinus Torvalds 5331da177e4SLinus Torvalds static int init_inode(struct inode *inode, struct dentry *dentry) 5341da177e4SLinus Torvalds { 5351da177e4SLinus Torvalds char *name; 5361da177e4SLinus Torvalds int type, err = -ENOMEM; 5371da177e4SLinus Torvalds int maj, min; 5381da177e4SLinus Torvalds dev_t rdev = 0; 5391da177e4SLinus Torvalds 5401da177e4SLinus Torvalds if (dentry) { 5411da177e4SLinus Torvalds name = dentry_name(dentry, 0); 5421da177e4SLinus Torvalds if (name == NULL) 5431da177e4SLinus Torvalds goto out; 5441da177e4SLinus Torvalds type = file_type(name, &maj, &min); 5451da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 5461da177e4SLinus Torvalds rdev = MKDEV(maj, min); 5471da177e4SLinus Torvalds kfree(name); 5481da177e4SLinus Torvalds } 5491da177e4SLinus Torvalds else type = OS_TYPE_DIR; 5501da177e4SLinus Torvalds 5511da177e4SLinus Torvalds err = 0; 5521da177e4SLinus Torvalds if (type == OS_TYPE_SYMLINK) 5531da177e4SLinus Torvalds inode->i_op = &page_symlink_inode_operations; 5541da177e4SLinus Torvalds else if (type == OS_TYPE_DIR) 5551da177e4SLinus Torvalds inode->i_op = &hostfs_dir_iops; 5561da177e4SLinus Torvalds else inode->i_op = &hostfs_iops; 5571da177e4SLinus Torvalds 5581da177e4SLinus Torvalds if (type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops; 5591da177e4SLinus Torvalds else inode->i_fop = &hostfs_file_fops; 5601da177e4SLinus Torvalds 5611da177e4SLinus Torvalds if (type == OS_TYPE_SYMLINK) 5621da177e4SLinus Torvalds inode->i_mapping->a_ops = &hostfs_link_aops; 5631da177e4SLinus Torvalds else inode->i_mapping->a_ops = &hostfs_aops; 5641da177e4SLinus Torvalds 5651da177e4SLinus Torvalds switch (type) { 5661da177e4SLinus Torvalds case OS_TYPE_CHARDEV: 5671da177e4SLinus Torvalds init_special_inode(inode, S_IFCHR, rdev); 5681da177e4SLinus Torvalds break; 5691da177e4SLinus Torvalds case OS_TYPE_BLOCKDEV: 5701da177e4SLinus Torvalds init_special_inode(inode, S_IFBLK, rdev); 5711da177e4SLinus Torvalds break; 5721da177e4SLinus Torvalds case OS_TYPE_FIFO: 5731da177e4SLinus Torvalds init_special_inode(inode, S_IFIFO, 0); 5741da177e4SLinus Torvalds break; 5751da177e4SLinus Torvalds case OS_TYPE_SOCK: 5761da177e4SLinus Torvalds init_special_inode(inode, S_IFSOCK, 0); 5771da177e4SLinus Torvalds break; 5781da177e4SLinus Torvalds } 5791da177e4SLinus Torvalds out: 580f1adc05eSJeff Dike return err; 5811da177e4SLinus Torvalds } 5821da177e4SLinus Torvalds 5831da177e4SLinus Torvalds int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, 5841da177e4SLinus Torvalds struct nameidata *nd) 5851da177e4SLinus Torvalds { 5861da177e4SLinus Torvalds struct inode *inode; 5871da177e4SLinus Torvalds char *name; 5881da177e4SLinus Torvalds int error, fd; 5891da177e4SLinus Torvalds 5900a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5910a370e5dSDavid Howells if (IS_ERR(inode)) { 5920a370e5dSDavid Howells error = PTR_ERR(inode); 59384b3db04SJeff Dike goto out; 5940a370e5dSDavid Howells } 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds error = init_inode(inode, dentry); 5971da177e4SLinus Torvalds if (error) 5981da177e4SLinus Torvalds goto out_put; 5991da177e4SLinus Torvalds 6001da177e4SLinus Torvalds error = -ENOMEM; 6011da177e4SLinus Torvalds name = dentry_name(dentry, 0); 6021da177e4SLinus Torvalds if (name == NULL) 6031da177e4SLinus Torvalds goto out_put; 6041da177e4SLinus Torvalds 6051da177e4SLinus Torvalds fd = file_create(name, 6061da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 6071da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 6081da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 6091da177e4SLinus Torvalds if (fd < 0) 6101da177e4SLinus Torvalds error = fd; 6111da177e4SLinus Torvalds else error = read_name(inode, name); 6121da177e4SLinus Torvalds 6131da177e4SLinus Torvalds kfree(name); 6141da177e4SLinus Torvalds if (error) 6151da177e4SLinus Torvalds goto out_put; 6161da177e4SLinus Torvalds 6171da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 6181da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 6191da177e4SLinus Torvalds d_instantiate(dentry, inode); 620f1adc05eSJeff Dike return 0; 6211da177e4SLinus Torvalds 6221da177e4SLinus Torvalds out_put: 6231da177e4SLinus Torvalds iput(inode); 6241da177e4SLinus Torvalds out: 625f1adc05eSJeff Dike return error; 6261da177e4SLinus Torvalds } 6271da177e4SLinus Torvalds 6281da177e4SLinus Torvalds struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 6291da177e4SLinus Torvalds struct nameidata *nd) 6301da177e4SLinus Torvalds { 6311da177e4SLinus Torvalds struct inode *inode; 6321da177e4SLinus Torvalds char *name; 6331da177e4SLinus Torvalds int err; 6341da177e4SLinus Torvalds 6350a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 6360a370e5dSDavid Howells if (IS_ERR(inode)) { 6370a370e5dSDavid Howells err = PTR_ERR(inode); 6381da177e4SLinus Torvalds goto out; 6390a370e5dSDavid Howells } 6401da177e4SLinus Torvalds 6411da177e4SLinus Torvalds err = init_inode(inode, dentry); 6421da177e4SLinus Torvalds if (err) 6431da177e4SLinus Torvalds goto out_put; 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds err = -ENOMEM; 6461da177e4SLinus Torvalds name = dentry_name(dentry, 0); 6471da177e4SLinus Torvalds if (name == NULL) 6481da177e4SLinus Torvalds goto out_put; 6491da177e4SLinus Torvalds 6501da177e4SLinus Torvalds err = read_name(inode, name); 6511da177e4SLinus Torvalds kfree(name); 6521da177e4SLinus Torvalds if (err == -ENOENT) { 6531da177e4SLinus Torvalds iput(inode); 6541da177e4SLinus Torvalds inode = NULL; 6551da177e4SLinus Torvalds } 6561da177e4SLinus Torvalds else if (err) 6571da177e4SLinus Torvalds goto out_put; 6581da177e4SLinus Torvalds 6591da177e4SLinus Torvalds d_add(dentry, inode); 6601da177e4SLinus Torvalds dentry->d_op = &hostfs_dentry_ops; 661f1adc05eSJeff Dike return NULL; 6621da177e4SLinus Torvalds 6631da177e4SLinus Torvalds out_put: 6641da177e4SLinus Torvalds iput(inode); 6651da177e4SLinus Torvalds out: 666f1adc05eSJeff Dike return ERR_PTR(err); 6671da177e4SLinus Torvalds } 6681da177e4SLinus Torvalds 6691da177e4SLinus Torvalds static char *inode_dentry_name(struct inode *ino, struct dentry *dentry) 6701da177e4SLinus Torvalds { 6711da177e4SLinus Torvalds char *file; 6721da177e4SLinus Torvalds int len; 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds file = inode_name(ino, dentry->d_name.len + 1); 675f1adc05eSJeff Dike if (file == NULL) 676f1adc05eSJeff Dike return NULL; 6771da177e4SLinus Torvalds strcat(file, "/"); 6781da177e4SLinus Torvalds len = strlen(file); 6791da177e4SLinus Torvalds strncat(file, dentry->d_name.name, dentry->d_name.len); 6801da177e4SLinus Torvalds file[len + dentry->d_name.len] = '\0'; 681f1adc05eSJeff Dike return file; 6821da177e4SLinus Torvalds } 6831da177e4SLinus Torvalds 6841da177e4SLinus Torvalds int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) 6851da177e4SLinus Torvalds { 6861da177e4SLinus Torvalds char *from_name, *to_name; 6871da177e4SLinus Torvalds int err; 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds if ((from_name = inode_dentry_name(ino, from)) == NULL) 690f1adc05eSJeff Dike return -ENOMEM; 6911da177e4SLinus Torvalds to_name = dentry_name(to, 0); 6921da177e4SLinus Torvalds if (to_name == NULL) { 6931da177e4SLinus Torvalds kfree(from_name); 694f1adc05eSJeff Dike return -ENOMEM; 6951da177e4SLinus Torvalds } 6961da177e4SLinus Torvalds err = link_file(to_name, from_name); 6971da177e4SLinus Torvalds kfree(from_name); 6981da177e4SLinus Torvalds kfree(to_name); 699f1adc05eSJeff Dike return err; 7001da177e4SLinus Torvalds } 7011da177e4SLinus Torvalds 7021da177e4SLinus Torvalds int hostfs_unlink(struct inode *ino, struct dentry *dentry) 7031da177e4SLinus Torvalds { 7041da177e4SLinus Torvalds char *file; 7051da177e4SLinus Torvalds int err; 7061da177e4SLinus Torvalds 707f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 708f1adc05eSJeff Dike return -ENOMEM; 7091da177e4SLinus Torvalds if (append) 710f1adc05eSJeff Dike return -EPERM; 7111da177e4SLinus Torvalds 7121da177e4SLinus Torvalds err = unlink_file(file); 7131da177e4SLinus Torvalds kfree(file); 714f1adc05eSJeff Dike return err; 7151da177e4SLinus Torvalds } 7161da177e4SLinus Torvalds 7171da177e4SLinus Torvalds int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) 7181da177e4SLinus Torvalds { 7191da177e4SLinus Torvalds char *file; 7201da177e4SLinus Torvalds int err; 7211da177e4SLinus Torvalds 722f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 723f1adc05eSJeff Dike return -ENOMEM; 7241da177e4SLinus Torvalds err = make_symlink(file, to); 7251da177e4SLinus Torvalds kfree(file); 726f1adc05eSJeff Dike return err; 7271da177e4SLinus Torvalds } 7281da177e4SLinus Torvalds 7291da177e4SLinus Torvalds int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) 7301da177e4SLinus Torvalds { 7311da177e4SLinus Torvalds char *file; 7321da177e4SLinus Torvalds int err; 7331da177e4SLinus Torvalds 734f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 735f1adc05eSJeff Dike return -ENOMEM; 7361da177e4SLinus Torvalds err = do_mkdir(file, mode); 7371da177e4SLinus Torvalds kfree(file); 738f1adc05eSJeff Dike return err; 7391da177e4SLinus Torvalds } 7401da177e4SLinus Torvalds 7411da177e4SLinus Torvalds int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 7421da177e4SLinus Torvalds { 7431da177e4SLinus Torvalds char *file; 7441da177e4SLinus Torvalds int err; 7451da177e4SLinus Torvalds 746f1adc05eSJeff Dike if ((file = inode_dentry_name(ino, dentry)) == NULL) 747f1adc05eSJeff Dike return -ENOMEM; 7481da177e4SLinus Torvalds err = do_rmdir(file); 7491da177e4SLinus Torvalds kfree(file); 750f1adc05eSJeff Dike return err; 7511da177e4SLinus Torvalds } 7521da177e4SLinus Torvalds 7531da177e4SLinus Torvalds int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 7541da177e4SLinus Torvalds { 7551da177e4SLinus Torvalds struct inode *inode; 7561da177e4SLinus Torvalds char *name; 7570a370e5dSDavid Howells int err; 7581da177e4SLinus Torvalds 7590a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 7600a370e5dSDavid Howells if (IS_ERR(inode)) { 7610a370e5dSDavid Howells err = PTR_ERR(inode); 7621da177e4SLinus Torvalds goto out; 7630a370e5dSDavid Howells } 7641da177e4SLinus Torvalds 7651da177e4SLinus Torvalds err = init_inode(inode, dentry); 7661da177e4SLinus Torvalds if (err) 7671da177e4SLinus Torvalds goto out_put; 7681da177e4SLinus Torvalds 7691da177e4SLinus Torvalds err = -ENOMEM; 7701da177e4SLinus Torvalds name = dentry_name(dentry, 0); 7711da177e4SLinus Torvalds if (name == NULL) 7721da177e4SLinus Torvalds goto out_put; 7731da177e4SLinus Torvalds 7741da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 77588f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 7761da177e4SLinus Torvalds if (err) 7771da177e4SLinus Torvalds goto out_free; 7781da177e4SLinus Torvalds 7791da177e4SLinus Torvalds err = read_name(inode, name); 7801da177e4SLinus Torvalds kfree(name); 7811da177e4SLinus Torvalds if (err) 7821da177e4SLinus Torvalds goto out_put; 7831da177e4SLinus Torvalds 7841da177e4SLinus Torvalds d_instantiate(dentry, inode); 785f1adc05eSJeff Dike return 0; 7861da177e4SLinus Torvalds 7871da177e4SLinus Torvalds out_free: 7881da177e4SLinus Torvalds kfree(name); 7891da177e4SLinus Torvalds out_put: 7901da177e4SLinus Torvalds iput(inode); 7911da177e4SLinus Torvalds out: 792f1adc05eSJeff Dike return err; 7931da177e4SLinus Torvalds } 7941da177e4SLinus Torvalds 7951da177e4SLinus Torvalds int hostfs_rename(struct inode *from_ino, struct dentry *from, 7961da177e4SLinus Torvalds struct inode *to_ino, struct dentry *to) 7971da177e4SLinus Torvalds { 7981da177e4SLinus Torvalds char *from_name, *to_name; 7991da177e4SLinus Torvalds int err; 8001da177e4SLinus Torvalds 8011da177e4SLinus Torvalds if ((from_name = inode_dentry_name(from_ino, from)) == NULL) 802f1adc05eSJeff Dike return -ENOMEM; 8031da177e4SLinus Torvalds if ((to_name = inode_dentry_name(to_ino, to)) == NULL) { 8041da177e4SLinus Torvalds kfree(from_name); 805f1adc05eSJeff Dike return -ENOMEM; 8061da177e4SLinus Torvalds } 8071da177e4SLinus Torvalds err = rename_file(from_name, to_name); 8081da177e4SLinus Torvalds kfree(from_name); 8091da177e4SLinus Torvalds kfree(to_name); 810f1adc05eSJeff Dike return err; 8111da177e4SLinus Torvalds } 8121da177e4SLinus Torvalds 813e6305c43SAl Viro int hostfs_permission(struct inode *ino, int desired) 8141da177e4SLinus Torvalds { 8151da177e4SLinus Torvalds char *name; 8161da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 8171da177e4SLinus Torvalds 8181da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 8191da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 8201da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 8211da177e4SLinus Torvalds name = inode_name(ino, 0); 822f1adc05eSJeff Dike if (name == NULL) 823f1adc05eSJeff Dike return -ENOMEM; 8241da177e4SLinus Torvalds 8251da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 8261da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 8271da177e4SLinus Torvalds err = 0; 8281da177e4SLinus Torvalds else 8291da177e4SLinus Torvalds err = access_file(name, r, w, x); 8301da177e4SLinus Torvalds kfree(name); 8311da177e4SLinus Torvalds if (!err) 8321da177e4SLinus Torvalds err = generic_permission(ino, desired, NULL); 8331da177e4SLinus Torvalds return err; 8341da177e4SLinus Torvalds } 8351da177e4SLinus Torvalds 8361da177e4SLinus Torvalds int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 8371da177e4SLinus Torvalds { 8381025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 8391da177e4SLinus Torvalds struct hostfs_iattr attrs; 8401da177e4SLinus Torvalds char *name; 8411da177e4SLinus Torvalds int err; 8421da177e4SLinus Torvalds 8431025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 8445822b7faSAlberto Bertogli 8451025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 8461da177e4SLinus Torvalds if (err) 8471da177e4SLinus Torvalds return err; 8481da177e4SLinus Torvalds 8491da177e4SLinus Torvalds if (append) 8501da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 8511da177e4SLinus Torvalds 8521da177e4SLinus Torvalds attrs.ia_valid = 0; 8531da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 8541da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 8551da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 8561da177e4SLinus Torvalds } 8571da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 8581da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 8591da177e4SLinus Torvalds attrs.ia_uid = attr->ia_uid; 8601da177e4SLinus Torvalds } 8611da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 8621da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 8631da177e4SLinus Torvalds attrs.ia_gid = attr->ia_gid; 8641da177e4SLinus Torvalds } 8651da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 8661da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 8671da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 8681da177e4SLinus Torvalds } 8691da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 8701da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 8711da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 8721da177e4SLinus Torvalds } 8731da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 8741da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 8751da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 8761da177e4SLinus Torvalds } 8771da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 8781da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 8791da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 8801da177e4SLinus Torvalds } 8811da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 8821da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8831da177e4SLinus Torvalds } 8841da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8851da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8861da177e4SLinus Torvalds } 8871da177e4SLinus Torvalds name = dentry_name(dentry, 0); 888f1adc05eSJeff Dike if (name == NULL) 889f1adc05eSJeff Dike return -ENOMEM; 8905822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 8911da177e4SLinus Torvalds kfree(name); 8921da177e4SLinus Torvalds if (err) 893f1adc05eSJeff Dike return err; 8941da177e4SLinus Torvalds 8951025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 8961025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 8971025774cSChristoph Hellwig int error; 8981025774cSChristoph Hellwig 8991025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 9001025774cSChristoph Hellwig if (err) 9011025774cSChristoph Hellwig return err; 9021025774cSChristoph Hellwig } 9031025774cSChristoph Hellwig 9041025774cSChristoph Hellwig setattr_copy(inode, attr); 9051025774cSChristoph Hellwig mark_inode_dirty(inode); 9061025774cSChristoph Hellwig return 0; 9071da177e4SLinus Torvalds } 9081da177e4SLinus Torvalds 90992e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 9101da177e4SLinus Torvalds .create = hostfs_create, 9111da177e4SLinus Torvalds .link = hostfs_link, 9121da177e4SLinus Torvalds .unlink = hostfs_unlink, 9131da177e4SLinus Torvalds .symlink = hostfs_symlink, 9141da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 9151da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 9161da177e4SLinus Torvalds .mknod = hostfs_mknod, 9171da177e4SLinus Torvalds .rename = hostfs_rename, 9181da177e4SLinus Torvalds .permission = hostfs_permission, 9191da177e4SLinus Torvalds .setattr = hostfs_setattr, 9201da177e4SLinus Torvalds }; 9211da177e4SLinus Torvalds 92292e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 9231da177e4SLinus Torvalds .create = hostfs_create, 9241da177e4SLinus Torvalds .lookup = hostfs_lookup, 9251da177e4SLinus Torvalds .link = hostfs_link, 9261da177e4SLinus Torvalds .unlink = hostfs_unlink, 9271da177e4SLinus Torvalds .symlink = hostfs_symlink, 9281da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 9291da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 9301da177e4SLinus Torvalds .mknod = hostfs_mknod, 9311da177e4SLinus Torvalds .rename = hostfs_rename, 9321da177e4SLinus Torvalds .permission = hostfs_permission, 9331da177e4SLinus Torvalds .setattr = hostfs_setattr, 9341da177e4SLinus Torvalds }; 9351da177e4SLinus Torvalds 9361da177e4SLinus Torvalds int hostfs_link_readpage(struct file *file, struct page *page) 9371da177e4SLinus Torvalds { 9381da177e4SLinus Torvalds char *buffer, *name; 9391da177e4SLinus Torvalds int err; 9401da177e4SLinus Torvalds 9411da177e4SLinus Torvalds buffer = kmap(page); 9421da177e4SLinus Torvalds name = inode_name(page->mapping->host, 0); 943f1adc05eSJeff Dike if (name == NULL) 944f1adc05eSJeff Dike return -ENOMEM; 945ea7e743eSWANG Cong err = hostfs_do_readlink(name, buffer, PAGE_CACHE_SIZE); 9461da177e4SLinus Torvalds kfree(name); 9471da177e4SLinus Torvalds if (err == PAGE_CACHE_SIZE) 9481da177e4SLinus Torvalds err = -E2BIG; 9491da177e4SLinus Torvalds else if (err > 0) { 9501da177e4SLinus Torvalds flush_dcache_page(page); 9511da177e4SLinus Torvalds SetPageUptodate(page); 9521da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 9531da177e4SLinus Torvalds err = 0; 9541da177e4SLinus Torvalds } 9551da177e4SLinus Torvalds kunmap(page); 9561da177e4SLinus Torvalds unlock_page(page); 957f1adc05eSJeff Dike return err; 9581da177e4SLinus Torvalds } 9591da177e4SLinus Torvalds 960f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_link_aops = { 9611da177e4SLinus Torvalds .readpage = hostfs_link_readpage, 9621da177e4SLinus Torvalds }; 9631da177e4SLinus Torvalds 9641da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 9651da177e4SLinus Torvalds { 9661da177e4SLinus Torvalds struct inode *root_inode; 96775e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 9681da177e4SLinus Torvalds int err; 9691da177e4SLinus Torvalds 9701da177e4SLinus Torvalds sb->s_blocksize = 1024; 9711da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 9721da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 9731da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 974752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9751da177e4SLinus Torvalds 976a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 97775e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 97875e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9791da177e4SLinus Torvalds 9801da177e4SLinus Torvalds err = -ENOMEM; 98175e8defbSPaolo 'Blaisorblade' Giarrusso host_root_path = kmalloc(strlen(root_ino) + 1 98275e8defbSPaolo 'Blaisorblade' Giarrusso + strlen(req_root) + 1, GFP_KERNEL); 98375e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9841da177e4SLinus Torvalds goto out; 9851da177e4SLinus Torvalds 98675e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9871da177e4SLinus Torvalds 9880a370e5dSDavid Howells root_inode = hostfs_iget(sb); 9890a370e5dSDavid Howells if (IS_ERR(root_inode)) { 9900a370e5dSDavid Howells err = PTR_ERR(root_inode); 9911da177e4SLinus Torvalds goto out_free; 9920a370e5dSDavid Howells } 9931da177e4SLinus Torvalds 9941da177e4SLinus Torvalds err = init_inode(root_inode, NULL); 9951da177e4SLinus Torvalds if (err) 9961da177e4SLinus Torvalds goto out_put; 9971da177e4SLinus Torvalds 99875e8defbSPaolo 'Blaisorblade' Giarrusso HOSTFS_I(root_inode)->host_filename = host_root_path; 99984b3db04SJeff Dike /* 100084b3db04SJeff Dike * Avoid that in the error path, iput(root_inode) frees again 100184b3db04SJeff Dike * host_root_path through hostfs_destroy_inode! 100284b3db04SJeff Dike */ 100375e8defbSPaolo 'Blaisorblade' Giarrusso host_root_path = NULL; 10041da177e4SLinus Torvalds 10051da177e4SLinus Torvalds err = -ENOMEM; 10061da177e4SLinus Torvalds sb->s_root = d_alloc_root(root_inode); 10071da177e4SLinus Torvalds if (sb->s_root == NULL) 10081da177e4SLinus Torvalds goto out_put; 10091da177e4SLinus Torvalds 10100a370e5dSDavid Howells err = hostfs_read_inode(root_inode); 101151a14110SJeff Dike if (err) { 101251a14110SJeff Dike /* No iput in this case because the dput does that for us */ 101351a14110SJeff Dike dput(sb->s_root); 101451a14110SJeff Dike sb->s_root = NULL; 1015bca27113SPaolo 'Blaisorblade' Giarrusso goto out; 101651a14110SJeff Dike } 10171da177e4SLinus Torvalds 1018f1adc05eSJeff Dike return 0; 10191da177e4SLinus Torvalds 10201da177e4SLinus Torvalds out_put: 10211da177e4SLinus Torvalds iput(root_inode); 10221da177e4SLinus Torvalds out_free: 102375e8defbSPaolo 'Blaisorblade' Giarrusso kfree(host_root_path); 10241da177e4SLinus Torvalds out: 1025f1adc05eSJeff Dike return err; 10261da177e4SLinus Torvalds } 10271da177e4SLinus Torvalds 1028454e2398SDavid Howells static int hostfs_read_sb(struct file_system_type *type, 10291da177e4SLinus Torvalds int flags, const char *dev_name, 1030454e2398SDavid Howells void *data, struct vfsmount *mnt) 10311da177e4SLinus Torvalds { 1032454e2398SDavid Howells return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); 10331da177e4SLinus Torvalds } 10341da177e4SLinus Torvalds 10351da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 10361da177e4SLinus Torvalds .owner = THIS_MODULE, 10371da177e4SLinus Torvalds .name = "hostfs", 10381da177e4SLinus Torvalds .get_sb = hostfs_read_sb, 10391da177e4SLinus Torvalds .kill_sb = kill_anon_super, 10401da177e4SLinus Torvalds .fs_flags = 0, 10411da177e4SLinus Torvalds }; 10421da177e4SLinus Torvalds 10431da177e4SLinus Torvalds static int __init init_hostfs(void) 10441da177e4SLinus Torvalds { 1045f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 10461da177e4SLinus Torvalds } 10471da177e4SLinus Torvalds 10481da177e4SLinus Torvalds static void __exit exit_hostfs(void) 10491da177e4SLinus Torvalds { 10501da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 10511da177e4SLinus Torvalds } 10521da177e4SLinus Torvalds 10531da177e4SLinus Torvalds module_init(init_hostfs) 10541da177e4SLinus Torvalds module_exit(exit_hostfs) 10551da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 1056