11da177e4SLinus Torvalds /* 2f1adc05eSJeff Dike * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 31da177e4SLinus Torvalds * Licensed under the GPL 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Ported the filesystem routines to 2.5. 61da177e4SLinus Torvalds * 2003-02-10 Petr Baudis <pasky@ucw.cz> 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds #include <linux/fs.h> 101da177e4SLinus Torvalds #include <linux/module.h> 1184b3db04SJeff Dike #include <linux/mm.h> 121da177e4SLinus Torvalds #include <linux/pagemap.h> 131da177e4SLinus Torvalds #include <linux/statfs.h> 145a0e3ad6STejun Heo #include <linux/slab.h> 15dd2cc4dfSMiklos Szeredi #include <linux/seq_file.h> 166966a977SJiri Kosina #include <linux/mount.h> 17d0352d3eSAl Viro #include <linux/namei.h> 181da177e4SLinus Torvalds #include "hostfs.h" 191da177e4SLinus Torvalds #include "init.h" 2084b3db04SJeff Dike #include "kern.h" 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds struct hostfs_inode_info { 231da177e4SLinus Torvalds int fd; 24aeb5d727SAl Viro fmode_t mode; 251da177e4SLinus Torvalds struct inode vfs_inode; 261da177e4SLinus Torvalds }; 271da177e4SLinus Torvalds 281da177e4SLinus Torvalds static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode) 291da177e4SLinus Torvalds { 30f1adc05eSJeff Dike return list_entry(inode, struct hostfs_inode_info, vfs_inode); 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds 33680b0da9SJosef Sipek #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode) 341da177e4SLinus Torvalds 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; 52d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops; 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds #ifndef MODULE 551da177e4SLinus Torvalds static int __init hostfs_args(char *options, int *add) 561da177e4SLinus Torvalds { 571da177e4SLinus Torvalds char *ptr; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds ptr = strchr(options, ','); 601da177e4SLinus Torvalds if (ptr != NULL) 611da177e4SLinus Torvalds *ptr++ = '\0'; 621da177e4SLinus Torvalds if (*options != '\0') 631da177e4SLinus Torvalds root_ino = options; 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds options = ptr; 661da177e4SLinus Torvalds while (options) { 671da177e4SLinus Torvalds ptr = strchr(options, ','); 681da177e4SLinus Torvalds if (ptr != NULL) 691da177e4SLinus Torvalds *ptr++ = '\0'; 701da177e4SLinus Torvalds if (*options != '\0') { 711da177e4SLinus Torvalds if (!strcmp(options, "append")) 721da177e4SLinus Torvalds append = 1; 731da177e4SLinus Torvalds else printf("hostfs_args - unsupported option - %s\n", 741da177e4SLinus Torvalds options); 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds options = ptr; 771da177e4SLinus Torvalds } 78f1adc05eSJeff Dike return 0; 791da177e4SLinus Torvalds } 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds __uml_setup("hostfs=", hostfs_args, 821da177e4SLinus Torvalds "hostfs=<root dir>,<flags>,...\n" 831da177e4SLinus Torvalds " This is used to set hostfs parameters. The root directory argument\n" 841da177e4SLinus Torvalds " is used to confine all hostfs mounts to within the specified directory\n" 851da177e4SLinus Torvalds " tree on the host. If this isn't specified, then a user inside UML can\n" 861da177e4SLinus Torvalds " mount anything on the host that's accessible to the user that's running\n" 871da177e4SLinus Torvalds " it.\n" 881da177e4SLinus Torvalds " The only flag currently supported is 'append', which specifies that all\n" 891da177e4SLinus Torvalds " files opened by hostfs will be opened in append mode.\n\n" 901da177e4SLinus Torvalds ); 911da177e4SLinus Torvalds #endif 921da177e4SLinus Torvalds 93c5322220SAl Viro static char *dentry_name(struct dentry *dentry) 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 106601d2c38SAl Viro root = parent->d_sb->s_fs_info; 1071da177e4SLinus Torvalds len += strlen(root); 108c5322220SAl Viro name = kmalloc(len + 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 125c5322220SAl Viro static char *inode_name(struct inode *ino) 1261da177e4SLinus Torvalds { 1271da177e4SLinus Torvalds struct dentry *dentry; 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias); 130c5322220SAl Viro return dentry_name(dentry); 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds static char *follow_link(char *link) 1341da177e4SLinus Torvalds { 1351da177e4SLinus Torvalds int len, n; 1361da177e4SLinus Torvalds char *name, *resolved, *end; 1371da177e4SLinus Torvalds 1381da177e4SLinus Torvalds len = 64; 1391da177e4SLinus Torvalds while (1) { 1401da177e4SLinus Torvalds n = -ENOMEM; 1411da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1421da177e4SLinus Torvalds if (name == NULL) 1431da177e4SLinus Torvalds goto out; 1441da177e4SLinus Torvalds 145ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1461da177e4SLinus Torvalds if (n < len) 1471da177e4SLinus Torvalds break; 1481da177e4SLinus Torvalds len *= 2; 1491da177e4SLinus Torvalds kfree(name); 1501da177e4SLinus Torvalds } 1511da177e4SLinus Torvalds if (n < 0) 1521da177e4SLinus Torvalds goto out_free; 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds if (*name == '/') 155f1adc05eSJeff Dike return name; 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds end = strrchr(link, '/'); 1581da177e4SLinus Torvalds if (end == NULL) 159f1adc05eSJeff Dike return name; 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds *(end + 1) = '\0'; 1621da177e4SLinus Torvalds len = strlen(link) + strlen(name) + 1; 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1651da177e4SLinus Torvalds if (resolved == NULL) { 1661da177e4SLinus Torvalds n = -ENOMEM; 1671da177e4SLinus Torvalds goto out_free; 1681da177e4SLinus Torvalds } 1691da177e4SLinus Torvalds 1701da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1711da177e4SLinus Torvalds kfree(name); 1721da177e4SLinus Torvalds kfree(link); 173f1adc05eSJeff Dike return resolved; 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds out_free: 1761da177e4SLinus Torvalds kfree(name); 1771da177e4SLinus Torvalds out: 178f1adc05eSJeff Dike return ERR_PTR(n); 1791da177e4SLinus Torvalds } 1801da177e4SLinus Torvalds 1810a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1820a370e5dSDavid Howells { 18352b209f7SAl Viro struct inode *inode = new_inode(sb); 1840a370e5dSDavid Howells if (!inode) 1850a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 1860a370e5dSDavid Howells return inode; 1870a370e5dSDavid Howells } 1880a370e5dSDavid Howells 189726c3342SDavid Howells int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 1901da177e4SLinus Torvalds { 19184b3db04SJeff Dike /* 19284b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 1931da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 1941da177e4SLinus Torvalds * so we convert them here 1951da177e4SLinus Torvalds */ 1961da177e4SLinus Torvalds int err; 1971da177e4SLinus Torvalds long long f_blocks; 1981da177e4SLinus Torvalds long long f_bfree; 1991da177e4SLinus Torvalds long long f_bavail; 2001da177e4SLinus Torvalds long long f_files; 2011da177e4SLinus Torvalds long long f_ffree; 2021da177e4SLinus Torvalds 203601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2041da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2051da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2061da177e4SLinus Torvalds &sf->f_namelen, sf->f_spare); 207f1adc05eSJeff Dike if (err) 208f1adc05eSJeff Dike return err; 2091da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2101da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2111da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2121da177e4SLinus Torvalds sf->f_files = f_files; 2131da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2141da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 215f1adc05eSJeff Dike return 0; 2161da177e4SLinus Torvalds } 2171da177e4SLinus Torvalds 2181da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2191da177e4SLinus Torvalds { 2201da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2211da177e4SLinus Torvalds 222601d2c38SAl Viro hi = kzalloc(sizeof(*hi), GFP_KERNEL); 2231da177e4SLinus Torvalds if (hi == NULL) 224f1adc05eSJeff Dike return NULL; 225601d2c38SAl Viro hi->fd = -1; 2261da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 227f1adc05eSJeff Dike return &hi->vfs_inode; 2281da177e4SLinus Torvalds } 2291da177e4SLinus Torvalds 230e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2311da177e4SLinus Torvalds { 232fef26658SMark Fasheh truncate_inode_pages(&inode->i_data, 0); 233e971a6d7SAl Viro end_writeback(inode); 2341da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 2351da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 2361da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 2371da177e4SLinus Torvalds } 2381da177e4SLinus Torvalds } 2391da177e4SLinus Torvalds 2401da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 2411da177e4SLinus Torvalds { 2421da177e4SLinus Torvalds kfree(HOSTFS_I(inode)); 2431da177e4SLinus Torvalds } 2441da177e4SLinus Torvalds 245dd2cc4dfSMiklos Szeredi static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 246dd2cc4dfSMiklos Szeredi { 247601d2c38SAl Viro const char *root_path = vfs->mnt_sb->s_fs_info; 248dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 249dd2cc4dfSMiklos Szeredi 250dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 251dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 252dd2cc4dfSMiklos Szeredi 253dd2cc4dfSMiklos Szeredi return 0; 254dd2cc4dfSMiklos Szeredi } 255dd2cc4dfSMiklos Szeredi 256ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 2571da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 2581da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 259e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 2601da177e4SLinus Torvalds .statfs = hostfs_statfs, 261dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 2621da177e4SLinus Torvalds }; 2631da177e4SLinus Torvalds 2641da177e4SLinus Torvalds int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) 2651da177e4SLinus Torvalds { 2661da177e4SLinus Torvalds void *dir; 2671da177e4SLinus Torvalds char *name; 2681da177e4SLinus Torvalds unsigned long long next, ino; 2691da177e4SLinus Torvalds int error, len; 2701da177e4SLinus Torvalds 271c5322220SAl Viro name = dentry_name(file->f_path.dentry); 272f1adc05eSJeff Dike if (name == NULL) 273f1adc05eSJeff Dike return -ENOMEM; 2741da177e4SLinus Torvalds dir = open_dir(name, &error); 2751da177e4SLinus Torvalds kfree(name); 276f1adc05eSJeff Dike if (dir == NULL) 277f1adc05eSJeff Dike return -error; 2781da177e4SLinus Torvalds next = file->f_pos; 2791da177e4SLinus Torvalds while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { 2801da177e4SLinus Torvalds error = (*filldir)(ent, name, len, file->f_pos, 2811da177e4SLinus Torvalds ino, DT_UNKNOWN); 2821da177e4SLinus Torvalds if (error) break; 2831da177e4SLinus Torvalds file->f_pos = next; 2841da177e4SLinus Torvalds } 2851da177e4SLinus Torvalds close_dir(dir); 286f1adc05eSJeff Dike return 0; 2871da177e4SLinus Torvalds } 2881da177e4SLinus Torvalds 2891da177e4SLinus Torvalds int hostfs_file_open(struct inode *ino, struct file *file) 2901da177e4SLinus Torvalds { 2911da177e4SLinus Torvalds char *name; 292aeb5d727SAl Viro fmode_t mode = 0; 293aeb5d727SAl Viro int r = 0, w = 0, fd; 2941da177e4SLinus Torvalds 2951da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 2961da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 297f1adc05eSJeff Dike return 0; 2981da177e4SLinus Torvalds 29984b3db04SJeff Dike /* 30084b3db04SJeff Dike * The file may already have been opened, but with the wrong access, 3011da177e4SLinus Torvalds * so this resets things and reopens the file with the new access. 3021da177e4SLinus Torvalds */ 3031da177e4SLinus Torvalds if (HOSTFS_I(ino)->fd != -1) { 3041da177e4SLinus Torvalds close_file(&HOSTFS_I(ino)->fd); 3051da177e4SLinus Torvalds HOSTFS_I(ino)->fd = -1; 3061da177e4SLinus Torvalds } 3071da177e4SLinus Torvalds 3081da177e4SLinus Torvalds HOSTFS_I(ino)->mode |= mode; 3091da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_READ) 3101da177e4SLinus Torvalds r = 1; 3111da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_WRITE) 3121da177e4SLinus Torvalds w = 1; 3131da177e4SLinus Torvalds if (w) 3141da177e4SLinus Torvalds r = 1; 3151da177e4SLinus Torvalds 316c5322220SAl Viro name = dentry_name(file->f_path.dentry); 3171da177e4SLinus Torvalds if (name == NULL) 318f1adc05eSJeff Dike return -ENOMEM; 3191da177e4SLinus Torvalds 3201da177e4SLinus Torvalds fd = open_file(name, r, w, append); 3211da177e4SLinus Torvalds kfree(name); 322f1adc05eSJeff Dike if (fd < 0) 323f1adc05eSJeff Dike return fd; 3241da177e4SLinus Torvalds FILE_HOSTFS_I(file)->fd = fd; 3251da177e4SLinus Torvalds 326f1adc05eSJeff Dike return 0; 3271da177e4SLinus Torvalds } 3281da177e4SLinus Torvalds 3297ea80859SChristoph Hellwig int hostfs_fsync(struct file *file, int datasync) 3301da177e4SLinus Torvalds { 3317ea80859SChristoph Hellwig return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); 3321da177e4SLinus Torvalds } 3331da177e4SLinus Torvalds 3344b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3351da177e4SLinus Torvalds .llseek = generic_file_llseek, 336543ade1fSBadari Pulavarty .read = do_sync_read, 3375ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 3381da177e4SLinus Torvalds .aio_read = generic_file_aio_read, 3391da177e4SLinus Torvalds .aio_write = generic_file_aio_write, 340543ade1fSBadari Pulavarty .write = do_sync_write, 3411da177e4SLinus Torvalds .mmap = generic_file_mmap, 3421da177e4SLinus Torvalds .open = hostfs_file_open, 3431da177e4SLinus Torvalds .release = NULL, 3441da177e4SLinus Torvalds .fsync = hostfs_fsync, 3451da177e4SLinus Torvalds }; 3461da177e4SLinus Torvalds 3474b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 3481da177e4SLinus Torvalds .llseek = generic_file_llseek, 3491da177e4SLinus Torvalds .readdir = hostfs_readdir, 3501da177e4SLinus Torvalds .read = generic_read_dir, 3511da177e4SLinus Torvalds }; 3521da177e4SLinus Torvalds 3531da177e4SLinus Torvalds int hostfs_writepage(struct page *page, struct writeback_control *wbc) 3541da177e4SLinus Torvalds { 3551da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 3561da177e4SLinus Torvalds struct inode *inode = mapping->host; 3571da177e4SLinus Torvalds char *buffer; 3581da177e4SLinus Torvalds unsigned long long base; 3591da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 3601da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 3611da177e4SLinus Torvalds int err; 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds if (page->index >= end_index) 3641da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds buffer = kmap(page); 3671da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 3681da177e4SLinus Torvalds 3691da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 3701da177e4SLinus Torvalds if (err != count) { 3711da177e4SLinus Torvalds ClearPageUptodate(page); 3721da177e4SLinus Torvalds goto out; 3731da177e4SLinus Torvalds } 3741da177e4SLinus Torvalds 3751da177e4SLinus Torvalds if (base > inode->i_size) 3761da177e4SLinus Torvalds inode->i_size = base; 3771da177e4SLinus Torvalds 3781da177e4SLinus Torvalds if (PageError(page)) 3791da177e4SLinus Torvalds ClearPageError(page); 3801da177e4SLinus Torvalds err = 0; 3811da177e4SLinus Torvalds 3821da177e4SLinus Torvalds out: 3831da177e4SLinus Torvalds kunmap(page); 3841da177e4SLinus Torvalds 3851da177e4SLinus Torvalds unlock_page(page); 3861da177e4SLinus Torvalds return err; 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds 3891da177e4SLinus Torvalds int hostfs_readpage(struct file *file, struct page *page) 3901da177e4SLinus Torvalds { 3911da177e4SLinus Torvalds char *buffer; 3921da177e4SLinus Torvalds long long start; 3931da177e4SLinus Torvalds int err = 0; 3941da177e4SLinus Torvalds 3951da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 3961da177e4SLinus Torvalds buffer = kmap(page); 3971da177e4SLinus Torvalds err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 3981da177e4SLinus Torvalds PAGE_CACHE_SIZE); 39984b3db04SJeff Dike if (err < 0) 40084b3db04SJeff Dike goto out; 4011da177e4SLinus Torvalds 4021da177e4SLinus Torvalds memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); 4031da177e4SLinus Torvalds 4041da177e4SLinus Torvalds flush_dcache_page(page); 4051da177e4SLinus Torvalds SetPageUptodate(page); 4061da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 4071da177e4SLinus Torvalds err = 0; 4081da177e4SLinus Torvalds out: 4091da177e4SLinus Torvalds kunmap(page); 4101da177e4SLinus Torvalds unlock_page(page); 411f1adc05eSJeff Dike return err; 4121da177e4SLinus Torvalds } 4131da177e4SLinus Torvalds 414ae361ff4SNick Piggin int hostfs_write_begin(struct file *file, struct address_space *mapping, 415ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 416ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4171da177e4SLinus Torvalds { 418ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 419ae361ff4SNick Piggin 42054566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 421ae361ff4SNick Piggin if (!*pagep) 422ae361ff4SNick Piggin return -ENOMEM; 423ae361ff4SNick Piggin return 0; 424ae361ff4SNick Piggin } 425ae361ff4SNick Piggin 426ae361ff4SNick Piggin int hostfs_write_end(struct file *file, struct address_space *mapping, 427ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 428ae361ff4SNick Piggin struct page *page, void *fsdata) 429ae361ff4SNick Piggin { 430ae361ff4SNick Piggin struct inode *inode = mapping->host; 431ae361ff4SNick Piggin void *buffer; 432ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 4331da177e4SLinus Torvalds int err; 4341da177e4SLinus Torvalds 4351da177e4SLinus Torvalds buffer = kmap(page); 436ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 4371da177e4SLinus Torvalds kunmap(page); 4381da177e4SLinus Torvalds 439ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 440ae361ff4SNick Piggin SetPageUptodate(page); 4411da177e4SLinus Torvalds 44284b3db04SJeff Dike /* 44384b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 444ae361ff4SNick Piggin * i_size against the last byte written. 445ae361ff4SNick Piggin */ 446ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 447ae361ff4SNick Piggin inode->i_size = pos; 448ae361ff4SNick Piggin unlock_page(page); 449ae361ff4SNick Piggin page_cache_release(page); 45030f04a4eSPaolo 'Blaisorblade' Giarrusso 451f1adc05eSJeff Dike return err; 4521da177e4SLinus Torvalds } 4531da177e4SLinus Torvalds 454f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 4551da177e4SLinus Torvalds .writepage = hostfs_writepage, 4561da177e4SLinus Torvalds .readpage = hostfs_readpage, 457ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 458ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 459ae361ff4SNick Piggin .write_end = hostfs_write_end, 4601da177e4SLinus Torvalds }; 4611da177e4SLinus Torvalds 4624754b825SAl Viro static int read_name(struct inode *ino, char *name) 4631da177e4SLinus Torvalds { 4644754b825SAl Viro dev_t rdev; 4654754b825SAl Viro struct hostfs_stat st; 4664754b825SAl Viro int err = stat_file(name, &st, -1); 4674754b825SAl Viro if (err) 4684754b825SAl Viro return err; 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 4714754b825SAl Viro rdev = MKDEV(st.maj, st.min); 4721da177e4SLinus Torvalds 4734754b825SAl Viro switch (st.mode & S_IFMT) { 4744754b825SAl Viro case S_IFLNK: 475d0352d3eSAl Viro ino->i_op = &hostfs_link_iops; 4764754b825SAl Viro break; 4774754b825SAl Viro case S_IFDIR: 4784754b825SAl Viro ino->i_op = &hostfs_dir_iops; 4794754b825SAl Viro ino->i_fop = &hostfs_dir_fops; 4804754b825SAl Viro break; 4814754b825SAl Viro case S_IFCHR: 4824754b825SAl Viro case S_IFBLK: 4834754b825SAl Viro case S_IFIFO: 4844754b825SAl Viro case S_IFSOCK: 4854754b825SAl Viro init_special_inode(ino, st.mode & S_IFMT, rdev); 4864754b825SAl Viro ino->i_op = &hostfs_iops; 4874754b825SAl Viro break; 4881da177e4SLinus Torvalds 4894754b825SAl Viro default: 4904754b825SAl Viro ino->i_op = &hostfs_iops; 4914754b825SAl Viro ino->i_fop = &hostfs_file_fops; 4924754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops; 4931da177e4SLinus Torvalds } 4944754b825SAl Viro 4954754b825SAl Viro ino->i_ino = st.ino; 4964754b825SAl Viro ino->i_mode = st.mode; 4974754b825SAl Viro ino->i_nlink = st.nlink; 4984754b825SAl Viro ino->i_uid = st.uid; 4994754b825SAl Viro ino->i_gid = st.gid; 5004754b825SAl Viro ino->i_atime = st.atime; 5014754b825SAl Viro ino->i_mtime = st.mtime; 5024754b825SAl Viro ino->i_ctime = st.ctime; 5034754b825SAl Viro ino->i_size = st.size; 5044754b825SAl Viro ino->i_blocks = st.blocks; 5054754b825SAl Viro return 0; 5061da177e4SLinus Torvalds } 5071da177e4SLinus Torvalds 5081da177e4SLinus Torvalds int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, 5091da177e4SLinus Torvalds struct nameidata *nd) 5101da177e4SLinus Torvalds { 5111da177e4SLinus Torvalds struct inode *inode; 5121da177e4SLinus Torvalds char *name; 5131da177e4SLinus Torvalds int error, fd; 5141da177e4SLinus Torvalds 5150a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5160a370e5dSDavid Howells if (IS_ERR(inode)) { 5170a370e5dSDavid Howells error = PTR_ERR(inode); 51884b3db04SJeff Dike goto out; 5190a370e5dSDavid Howells } 5201da177e4SLinus Torvalds 5211da177e4SLinus Torvalds error = -ENOMEM; 522c5322220SAl Viro name = dentry_name(dentry); 5231da177e4SLinus Torvalds if (name == NULL) 5241da177e4SLinus Torvalds goto out_put; 5251da177e4SLinus Torvalds 5261da177e4SLinus Torvalds fd = file_create(name, 5271da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 5281da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 5291da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 5304754b825SAl Viro if (fd < 0) 5311da177e4SLinus Torvalds error = fd; 5324754b825SAl Viro else 5335e2df28cSAl Viro error = read_name(inode, name); 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds kfree(name); 5361da177e4SLinus Torvalds if (error) 5371da177e4SLinus Torvalds goto out_put; 5381da177e4SLinus Torvalds 5391da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 5401da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 5411da177e4SLinus Torvalds d_instantiate(dentry, inode); 542f1adc05eSJeff Dike return 0; 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds out_put: 5451da177e4SLinus Torvalds iput(inode); 5461da177e4SLinus Torvalds out: 547f1adc05eSJeff Dike return error; 5481da177e4SLinus Torvalds } 5491da177e4SLinus Torvalds 5501da177e4SLinus Torvalds struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 5511da177e4SLinus Torvalds struct nameidata *nd) 5521da177e4SLinus Torvalds { 5531da177e4SLinus Torvalds struct inode *inode; 5541da177e4SLinus Torvalds char *name; 5551da177e4SLinus Torvalds int err; 5561da177e4SLinus Torvalds 5570a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 5580a370e5dSDavid Howells if (IS_ERR(inode)) { 5590a370e5dSDavid Howells err = PTR_ERR(inode); 5601da177e4SLinus Torvalds goto out; 5610a370e5dSDavid Howells } 5621da177e4SLinus Torvalds 5631da177e4SLinus Torvalds err = -ENOMEM; 564c5322220SAl Viro name = dentry_name(dentry); 5651da177e4SLinus Torvalds if (name == NULL) 5661da177e4SLinus Torvalds goto out_put; 5671da177e4SLinus Torvalds 5681da177e4SLinus Torvalds err = read_name(inode, name); 5695e2df28cSAl Viro 5701da177e4SLinus Torvalds kfree(name); 5711da177e4SLinus Torvalds if (err == -ENOENT) { 5721da177e4SLinus Torvalds iput(inode); 5731da177e4SLinus Torvalds inode = NULL; 5741da177e4SLinus Torvalds } 5751da177e4SLinus Torvalds else if (err) 5761da177e4SLinus Torvalds goto out_put; 5771da177e4SLinus Torvalds 5781da177e4SLinus Torvalds d_add(dentry, inode); 5791da177e4SLinus Torvalds dentry->d_op = &hostfs_dentry_ops; 580f1adc05eSJeff Dike return NULL; 5811da177e4SLinus Torvalds 5821da177e4SLinus Torvalds out_put: 5831da177e4SLinus Torvalds iput(inode); 5841da177e4SLinus Torvalds out: 585f1adc05eSJeff Dike return ERR_PTR(err); 5861da177e4SLinus Torvalds } 5871da177e4SLinus Torvalds 5881da177e4SLinus Torvalds int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) 5891da177e4SLinus Torvalds { 5901da177e4SLinus Torvalds char *from_name, *to_name; 5911da177e4SLinus Torvalds int err; 5921da177e4SLinus Torvalds 593c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 594f1adc05eSJeff Dike return -ENOMEM; 595c5322220SAl Viro to_name = dentry_name(to); 5961da177e4SLinus Torvalds if (to_name == NULL) { 5971da177e4SLinus Torvalds kfree(from_name); 598f1adc05eSJeff Dike return -ENOMEM; 5991da177e4SLinus Torvalds } 6001da177e4SLinus Torvalds err = link_file(to_name, from_name); 6011da177e4SLinus Torvalds kfree(from_name); 6021da177e4SLinus Torvalds kfree(to_name); 603f1adc05eSJeff Dike return err; 6041da177e4SLinus Torvalds } 6051da177e4SLinus Torvalds 6061da177e4SLinus Torvalds int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6071da177e4SLinus Torvalds { 6081da177e4SLinus Torvalds char *file; 6091da177e4SLinus Torvalds int err; 6101da177e4SLinus Torvalds 611c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 612f1adc05eSJeff Dike return -ENOMEM; 6131da177e4SLinus Torvalds if (append) 614f1adc05eSJeff Dike return -EPERM; 6151da177e4SLinus Torvalds 6161da177e4SLinus Torvalds err = unlink_file(file); 6171da177e4SLinus Torvalds kfree(file); 618f1adc05eSJeff Dike return err; 6191da177e4SLinus Torvalds } 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) 6221da177e4SLinus Torvalds { 6231da177e4SLinus Torvalds char *file; 6241da177e4SLinus Torvalds int err; 6251da177e4SLinus Torvalds 626c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 627f1adc05eSJeff Dike return -ENOMEM; 6281da177e4SLinus Torvalds err = make_symlink(file, to); 6291da177e4SLinus Torvalds kfree(file); 630f1adc05eSJeff Dike return err; 6311da177e4SLinus Torvalds } 6321da177e4SLinus Torvalds 6331da177e4SLinus Torvalds int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) 6341da177e4SLinus Torvalds { 6351da177e4SLinus Torvalds char *file; 6361da177e4SLinus Torvalds int err; 6371da177e4SLinus Torvalds 638c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 639f1adc05eSJeff Dike return -ENOMEM; 6401da177e4SLinus Torvalds err = do_mkdir(file, mode); 6411da177e4SLinus Torvalds kfree(file); 642f1adc05eSJeff Dike return err; 6431da177e4SLinus Torvalds } 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 6461da177e4SLinus Torvalds { 6471da177e4SLinus Torvalds char *file; 6481da177e4SLinus Torvalds int err; 6491da177e4SLinus Torvalds 650c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 651f1adc05eSJeff Dike return -ENOMEM; 6521da177e4SLinus Torvalds err = do_rmdir(file); 6531da177e4SLinus Torvalds kfree(file); 654f1adc05eSJeff Dike return err; 6551da177e4SLinus Torvalds } 6561da177e4SLinus Torvalds 6571da177e4SLinus Torvalds int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 6581da177e4SLinus Torvalds { 6591da177e4SLinus Torvalds struct inode *inode; 6601da177e4SLinus Torvalds char *name; 6610a370e5dSDavid Howells int err; 6621da177e4SLinus Torvalds 6630a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 6640a370e5dSDavid Howells if (IS_ERR(inode)) { 6650a370e5dSDavid Howells err = PTR_ERR(inode); 6661da177e4SLinus Torvalds goto out; 6670a370e5dSDavid Howells } 6681da177e4SLinus Torvalds 6691da177e4SLinus Torvalds err = -ENOMEM; 670c5322220SAl Viro name = dentry_name(dentry); 6711da177e4SLinus Torvalds if (name == NULL) 6721da177e4SLinus Torvalds goto out_put; 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 67588f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 6761da177e4SLinus Torvalds if (err) 6771da177e4SLinus Torvalds goto out_free; 6781da177e4SLinus Torvalds 6791da177e4SLinus Torvalds err = read_name(inode, name); 6805e2df28cSAl Viro if (err) 6815e2df28cSAl Viro goto out_put; 6821da177e4SLinus Torvalds kfree(name); 6831da177e4SLinus Torvalds if (err) 6841da177e4SLinus Torvalds goto out_put; 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds d_instantiate(dentry, inode); 687f1adc05eSJeff Dike return 0; 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds out_free: 6901da177e4SLinus Torvalds kfree(name); 6911da177e4SLinus Torvalds out_put: 6921da177e4SLinus Torvalds iput(inode); 6931da177e4SLinus Torvalds out: 694f1adc05eSJeff Dike return err; 6951da177e4SLinus Torvalds } 6961da177e4SLinus Torvalds 6971da177e4SLinus Torvalds int hostfs_rename(struct inode *from_ino, struct dentry *from, 6981da177e4SLinus Torvalds struct inode *to_ino, struct dentry *to) 6991da177e4SLinus Torvalds { 7001da177e4SLinus Torvalds char *from_name, *to_name; 7011da177e4SLinus Torvalds int err; 7021da177e4SLinus Torvalds 703c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 704f1adc05eSJeff Dike return -ENOMEM; 705c5322220SAl Viro if ((to_name = dentry_name(to)) == NULL) { 7061da177e4SLinus Torvalds kfree(from_name); 707f1adc05eSJeff Dike return -ENOMEM; 7081da177e4SLinus Torvalds } 7091da177e4SLinus Torvalds err = rename_file(from_name, to_name); 7101da177e4SLinus Torvalds kfree(from_name); 7111da177e4SLinus Torvalds kfree(to_name); 712f1adc05eSJeff Dike return err; 7131da177e4SLinus Torvalds } 7141da177e4SLinus Torvalds 715e6305c43SAl Viro int hostfs_permission(struct inode *ino, int desired) 7161da177e4SLinus Torvalds { 7171da177e4SLinus Torvalds char *name; 7181da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7191da177e4SLinus Torvalds 7201da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7211da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7221da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 723c5322220SAl Viro name = inode_name(ino); 724f1adc05eSJeff Dike if (name == NULL) 725f1adc05eSJeff Dike return -ENOMEM; 7261da177e4SLinus Torvalds 7271da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 7281da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 7291da177e4SLinus Torvalds err = 0; 7301da177e4SLinus Torvalds else 7311da177e4SLinus Torvalds err = access_file(name, r, w, x); 7321da177e4SLinus Torvalds kfree(name); 7331da177e4SLinus Torvalds if (!err) 7341da177e4SLinus Torvalds err = generic_permission(ino, desired, NULL); 7351da177e4SLinus Torvalds return err; 7361da177e4SLinus Torvalds } 7371da177e4SLinus Torvalds 7381da177e4SLinus Torvalds int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 7391da177e4SLinus Torvalds { 7401025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 7411da177e4SLinus Torvalds struct hostfs_iattr attrs; 7421da177e4SLinus Torvalds char *name; 7431da177e4SLinus Torvalds int err; 7441da177e4SLinus Torvalds 7451025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 7465822b7faSAlberto Bertogli 7471025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 7481da177e4SLinus Torvalds if (err) 7491da177e4SLinus Torvalds return err; 7501da177e4SLinus Torvalds 7511da177e4SLinus Torvalds if (append) 7521da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 7531da177e4SLinus Torvalds 7541da177e4SLinus Torvalds attrs.ia_valid = 0; 7551da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 7561da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 7571da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 7581da177e4SLinus Torvalds } 7591da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 7601da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 7611da177e4SLinus Torvalds attrs.ia_uid = attr->ia_uid; 7621da177e4SLinus Torvalds } 7631da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 7641da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 7651da177e4SLinus Torvalds attrs.ia_gid = attr->ia_gid; 7661da177e4SLinus Torvalds } 7671da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 7681da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 7691da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 7701da177e4SLinus Torvalds } 7711da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 7721da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 7731da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 7741da177e4SLinus Torvalds } 7751da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 7761da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 7771da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 7781da177e4SLinus Torvalds } 7791da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 7801da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 7811da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 7821da177e4SLinus Torvalds } 7831da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 7841da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 7851da177e4SLinus Torvalds } 7861da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 7871da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 7881da177e4SLinus Torvalds } 789c5322220SAl Viro name = dentry_name(dentry); 790f1adc05eSJeff Dike if (name == NULL) 791f1adc05eSJeff Dike return -ENOMEM; 7925822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 7931da177e4SLinus Torvalds kfree(name); 7941da177e4SLinus Torvalds if (err) 795f1adc05eSJeff Dike return err; 7961da177e4SLinus Torvalds 7971025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 7981025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 7991025774cSChristoph Hellwig int error; 8001025774cSChristoph Hellwig 8011025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 8021025774cSChristoph Hellwig if (err) 8031025774cSChristoph Hellwig return err; 8041025774cSChristoph Hellwig } 8051025774cSChristoph Hellwig 8061025774cSChristoph Hellwig setattr_copy(inode, attr); 8071025774cSChristoph Hellwig mark_inode_dirty(inode); 8081025774cSChristoph Hellwig return 0; 8091da177e4SLinus Torvalds } 8101da177e4SLinus Torvalds 81192e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8121da177e4SLinus Torvalds .create = hostfs_create, 8131da177e4SLinus Torvalds .link = hostfs_link, 8141da177e4SLinus Torvalds .unlink = hostfs_unlink, 8151da177e4SLinus Torvalds .symlink = hostfs_symlink, 8161da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8171da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8181da177e4SLinus Torvalds .mknod = hostfs_mknod, 8191da177e4SLinus Torvalds .rename = hostfs_rename, 8201da177e4SLinus Torvalds .permission = hostfs_permission, 8211da177e4SLinus Torvalds .setattr = hostfs_setattr, 8221da177e4SLinus Torvalds }; 8231da177e4SLinus Torvalds 82492e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8251da177e4SLinus Torvalds .create = hostfs_create, 8261da177e4SLinus Torvalds .lookup = hostfs_lookup, 8271da177e4SLinus Torvalds .link = hostfs_link, 8281da177e4SLinus Torvalds .unlink = hostfs_unlink, 8291da177e4SLinus Torvalds .symlink = hostfs_symlink, 8301da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8311da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8321da177e4SLinus Torvalds .mknod = hostfs_mknod, 8331da177e4SLinus Torvalds .rename = hostfs_rename, 8341da177e4SLinus Torvalds .permission = hostfs_permission, 8351da177e4SLinus Torvalds .setattr = hostfs_setattr, 8361da177e4SLinus Torvalds }; 8371da177e4SLinus Torvalds 838d0352d3eSAl Viro static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) 8391da177e4SLinus Torvalds { 840d0352d3eSAl Viro char *link = __getname(); 841d0352d3eSAl Viro if (link) { 842d0352d3eSAl Viro char *path = dentry_name(dentry); 843d0352d3eSAl Viro int err = -ENOMEM; 844d0352d3eSAl Viro if (path) { 845d0352d3eSAl Viro int err = hostfs_do_readlink(path, link, PATH_MAX); 846d0352d3eSAl Viro if (err == PATH_MAX) 8471da177e4SLinus Torvalds err = -E2BIG; 848d0352d3eSAl Viro kfree(path); 8491da177e4SLinus Torvalds } 850d0352d3eSAl Viro if (err < 0) { 851d0352d3eSAl Viro __putname(link); 852d0352d3eSAl Viro link = ERR_PTR(err); 853d0352d3eSAl Viro } 854d0352d3eSAl Viro } else { 855d0352d3eSAl Viro link = ERR_PTR(-ENOMEM); 8561da177e4SLinus Torvalds } 8571da177e4SLinus Torvalds 858d0352d3eSAl Viro nd_set_link(nd, link); 859d0352d3eSAl Viro return NULL; 860d0352d3eSAl Viro } 861d0352d3eSAl Viro 862d0352d3eSAl Viro static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 863d0352d3eSAl Viro { 864d0352d3eSAl Viro char *s = nd_get_link(nd); 865d0352d3eSAl Viro if (!IS_ERR(s)) 866d0352d3eSAl Viro __putname(s); 867d0352d3eSAl Viro } 868d0352d3eSAl Viro 869d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 870d0352d3eSAl Viro .readlink = generic_readlink, 871d0352d3eSAl Viro .follow_link = hostfs_follow_link, 872d0352d3eSAl Viro .put_link = hostfs_put_link, 8731da177e4SLinus Torvalds }; 8741da177e4SLinus Torvalds 8751da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 8761da177e4SLinus Torvalds { 8771da177e4SLinus Torvalds struct inode *root_inode; 87875e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 8791da177e4SLinus Torvalds int err; 8801da177e4SLinus Torvalds 8811da177e4SLinus Torvalds sb->s_blocksize = 1024; 8821da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 8831da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 8841da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 885752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 8861da177e4SLinus Torvalds 887a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 88875e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 88975e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 8901da177e4SLinus Torvalds 8911da177e4SLinus Torvalds err = -ENOMEM; 892601d2c38SAl Viro sb->s_fs_info = host_root_path = 893601d2c38SAl Viro kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); 89475e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 8951da177e4SLinus Torvalds goto out; 8961da177e4SLinus Torvalds 89775e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 8981da177e4SLinus Torvalds 89952b209f7SAl Viro root_inode = new_inode(sb); 90052b209f7SAl Viro if (!root_inode) 901601d2c38SAl Viro goto out; 9021da177e4SLinus Torvalds 9034754b825SAl Viro err = read_name(root_inode, host_root_path); 9044754b825SAl Viro if (err) 9054754b825SAl Viro goto out_put; 90652b209f7SAl Viro 9074754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 90852b209f7SAl Viro char *name = follow_link(host_root_path); 90952b209f7SAl Viro if (IS_ERR(name)) 91052b209f7SAl Viro err = PTR_ERR(name); 91152b209f7SAl Viro else 91252b209f7SAl Viro err = read_name(root_inode, name); 91352b209f7SAl Viro kfree(name); 9141da177e4SLinus Torvalds if (err) 9151da177e4SLinus Torvalds goto out_put; 9164754b825SAl Viro } 9171da177e4SLinus Torvalds 9181da177e4SLinus Torvalds err = -ENOMEM; 9191da177e4SLinus Torvalds sb->s_root = d_alloc_root(root_inode); 9201da177e4SLinus Torvalds if (sb->s_root == NULL) 9211da177e4SLinus Torvalds goto out_put; 9221da177e4SLinus Torvalds 923f1adc05eSJeff Dike return 0; 9241da177e4SLinus Torvalds 9251da177e4SLinus Torvalds out_put: 9261da177e4SLinus Torvalds iput(root_inode); 9271da177e4SLinus Torvalds out: 928f1adc05eSJeff Dike return err; 9291da177e4SLinus Torvalds } 9301da177e4SLinus Torvalds 931454e2398SDavid Howells static int hostfs_read_sb(struct file_system_type *type, 9321da177e4SLinus Torvalds int flags, const char *dev_name, 933454e2398SDavid Howells void *data, struct vfsmount *mnt) 9341da177e4SLinus Torvalds { 935454e2398SDavid Howells return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); 9361da177e4SLinus Torvalds } 9371da177e4SLinus Torvalds 938601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 939601d2c38SAl Viro { 940601d2c38SAl Viro kill_anon_super(s); 941601d2c38SAl Viro kfree(s->s_fs_info); 942601d2c38SAl Viro } 943601d2c38SAl Viro 9441da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 9451da177e4SLinus Torvalds .owner = THIS_MODULE, 9461da177e4SLinus Torvalds .name = "hostfs", 9471da177e4SLinus Torvalds .get_sb = hostfs_read_sb, 948601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 9491da177e4SLinus Torvalds .fs_flags = 0, 9501da177e4SLinus Torvalds }; 9511da177e4SLinus Torvalds 9521da177e4SLinus Torvalds static int __init init_hostfs(void) 9531da177e4SLinus Torvalds { 954f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 9551da177e4SLinus Torvalds } 9561da177e4SLinus Torvalds 9571da177e4SLinus Torvalds static void __exit exit_hostfs(void) 9581da177e4SLinus Torvalds { 9591da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 9601da177e4SLinus Torvalds } 9611da177e4SLinus Torvalds 9621da177e4SLinus Torvalds module_init(init_hostfs) 9631da177e4SLinus Torvalds module_exit(exit_hostfs) 9641da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 965