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 93e9193059SAl Viro static char *__dentry_name(struct dentry *dentry, char *name) 94e9193059SAl Viro { 95e9193059SAl Viro char *p = __dentry_path(dentry, name, PATH_MAX); 96e9193059SAl Viro char *root; 97e9193059SAl Viro size_t len; 98e9193059SAl Viro 99e9193059SAl Viro spin_unlock(&dcache_lock); 100e9193059SAl Viro 101e9193059SAl Viro root = dentry->d_sb->s_fs_info; 102e9193059SAl Viro len = strlen(root); 103e9193059SAl Viro if (IS_ERR(p)) { 104e9193059SAl Viro __putname(name); 105e9193059SAl Viro return NULL; 106e9193059SAl Viro } 107e9193059SAl Viro strncpy(name, root, PATH_MAX); 108e9193059SAl Viro if (len > p - name) { 109e9193059SAl Viro __putname(name); 110e9193059SAl Viro return NULL; 111e9193059SAl Viro } 112e9193059SAl Viro if (p > name + len) { 113e9193059SAl Viro char *s = name + len; 114e9193059SAl Viro while ((*s++ = *p++) != '\0') 115e9193059SAl Viro ; 116e9193059SAl Viro } 117e9193059SAl Viro return name; 118e9193059SAl Viro } 119e9193059SAl Viro 120c5322220SAl Viro static char *dentry_name(struct dentry *dentry) 1211da177e4SLinus Torvalds { 122e9193059SAl Viro char *name = __getname(); 123e9193059SAl Viro if (!name) 124f1adc05eSJeff Dike return NULL; 1251da177e4SLinus Torvalds 126e9193059SAl Viro spin_lock(&dcache_lock); 127e9193059SAl Viro return __dentry_name(dentry, name); /* will unlock */ 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds 130c5322220SAl Viro static char *inode_name(struct inode *ino) 1311da177e4SLinus Torvalds { 1321da177e4SLinus Torvalds struct dentry *dentry; 133e9193059SAl Viro char *name = __getname(); 134e9193059SAl Viro if (!name) 135e9193059SAl Viro return NULL; 1361da177e4SLinus Torvalds 137e9193059SAl Viro spin_lock(&dcache_lock); 138e9193059SAl Viro if (list_empty(&ino->i_dentry)) { 139e9193059SAl Viro spin_unlock(&dcache_lock); 140e9193059SAl Viro __putname(name); 141e9193059SAl Viro return NULL; 142e9193059SAl Viro } 143e9193059SAl Viro dentry = list_first_entry(&ino->i_dentry, struct dentry, d_alias); 144e9193059SAl Viro return __dentry_name(dentry, name); /* will unlock */ 1451da177e4SLinus Torvalds } 1461da177e4SLinus Torvalds 1471da177e4SLinus Torvalds static char *follow_link(char *link) 1481da177e4SLinus Torvalds { 1491da177e4SLinus Torvalds int len, n; 1501da177e4SLinus Torvalds char *name, *resolved, *end; 1511da177e4SLinus Torvalds 1521da177e4SLinus Torvalds len = 64; 1531da177e4SLinus Torvalds while (1) { 1541da177e4SLinus Torvalds n = -ENOMEM; 1551da177e4SLinus Torvalds name = kmalloc(len, GFP_KERNEL); 1561da177e4SLinus Torvalds if (name == NULL) 1571da177e4SLinus Torvalds goto out; 1581da177e4SLinus Torvalds 159ea7e743eSWANG Cong n = hostfs_do_readlink(link, name, len); 1601da177e4SLinus Torvalds if (n < len) 1611da177e4SLinus Torvalds break; 1621da177e4SLinus Torvalds len *= 2; 1631da177e4SLinus Torvalds kfree(name); 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds if (n < 0) 1661da177e4SLinus Torvalds goto out_free; 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds if (*name == '/') 169f1adc05eSJeff Dike return name; 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds end = strrchr(link, '/'); 1721da177e4SLinus Torvalds if (end == NULL) 173f1adc05eSJeff Dike return name; 1741da177e4SLinus Torvalds 1751da177e4SLinus Torvalds *(end + 1) = '\0'; 1761da177e4SLinus Torvalds len = strlen(link) + strlen(name) + 1; 1771da177e4SLinus Torvalds 1781da177e4SLinus Torvalds resolved = kmalloc(len, GFP_KERNEL); 1791da177e4SLinus Torvalds if (resolved == NULL) { 1801da177e4SLinus Torvalds n = -ENOMEM; 1811da177e4SLinus Torvalds goto out_free; 1821da177e4SLinus Torvalds } 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds sprintf(resolved, "%s%s", link, name); 1851da177e4SLinus Torvalds kfree(name); 1861da177e4SLinus Torvalds kfree(link); 187f1adc05eSJeff Dike return resolved; 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds out_free: 1901da177e4SLinus Torvalds kfree(name); 1911da177e4SLinus Torvalds out: 192f1adc05eSJeff Dike return ERR_PTR(n); 1931da177e4SLinus Torvalds } 1941da177e4SLinus Torvalds 1950a370e5dSDavid Howells static struct inode *hostfs_iget(struct super_block *sb) 1960a370e5dSDavid Howells { 19752b209f7SAl Viro struct inode *inode = new_inode(sb); 1980a370e5dSDavid Howells if (!inode) 1990a370e5dSDavid Howells return ERR_PTR(-ENOMEM); 2000a370e5dSDavid Howells return inode; 2010a370e5dSDavid Howells } 2020a370e5dSDavid Howells 203726c3342SDavid Howells int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf) 2041da177e4SLinus Torvalds { 20584b3db04SJeff Dike /* 20684b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel 2071da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields, 2081da177e4SLinus Torvalds * so we convert them here 2091da177e4SLinus Torvalds */ 2101da177e4SLinus Torvalds int err; 2111da177e4SLinus Torvalds long long f_blocks; 2121da177e4SLinus Torvalds long long f_bfree; 2131da177e4SLinus Torvalds long long f_bavail; 2141da177e4SLinus Torvalds long long f_files; 2151da177e4SLinus Torvalds long long f_ffree; 2161da177e4SLinus Torvalds 217601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info, 2181da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files, 2191da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid), 2201da177e4SLinus Torvalds &sf->f_namelen, sf->f_spare); 221f1adc05eSJeff Dike if (err) 222f1adc05eSJeff Dike return err; 2231da177e4SLinus Torvalds sf->f_blocks = f_blocks; 2241da177e4SLinus Torvalds sf->f_bfree = f_bfree; 2251da177e4SLinus Torvalds sf->f_bavail = f_bavail; 2261da177e4SLinus Torvalds sf->f_files = f_files; 2271da177e4SLinus Torvalds sf->f_ffree = f_ffree; 2281da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC; 229f1adc05eSJeff Dike return 0; 2301da177e4SLinus Torvalds } 2311da177e4SLinus Torvalds 2321da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb) 2331da177e4SLinus Torvalds { 2341da177e4SLinus Torvalds struct hostfs_inode_info *hi; 2351da177e4SLinus Torvalds 236601d2c38SAl Viro hi = kzalloc(sizeof(*hi), GFP_KERNEL); 2371da177e4SLinus Torvalds if (hi == NULL) 238f1adc05eSJeff Dike return NULL; 239601d2c38SAl Viro hi->fd = -1; 2401da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode); 241f1adc05eSJeff Dike return &hi->vfs_inode; 2421da177e4SLinus Torvalds } 2431da177e4SLinus Torvalds 244e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode) 2451da177e4SLinus Torvalds { 246fef26658SMark Fasheh truncate_inode_pages(&inode->i_data, 0); 247e971a6d7SAl Viro end_writeback(inode); 2481da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) { 2491da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd); 2501da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1; 2511da177e4SLinus Torvalds } 2521da177e4SLinus Torvalds } 2531da177e4SLinus Torvalds 2541da177e4SLinus Torvalds static void hostfs_destroy_inode(struct inode *inode) 2551da177e4SLinus Torvalds { 2561da177e4SLinus Torvalds kfree(HOSTFS_I(inode)); 2571da177e4SLinus Torvalds } 2581da177e4SLinus Torvalds 259dd2cc4dfSMiklos Szeredi static int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs) 260dd2cc4dfSMiklos Szeredi { 261601d2c38SAl Viro const char *root_path = vfs->mnt_sb->s_fs_info; 262dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1; 263dd2cc4dfSMiklos Szeredi 264dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset) 265dd2cc4dfSMiklos Szeredi seq_printf(seq, ",%s", root_path + offset); 266dd2cc4dfSMiklos Szeredi 267dd2cc4dfSMiklos Szeredi return 0; 268dd2cc4dfSMiklos Szeredi } 269dd2cc4dfSMiklos Szeredi 270ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = { 2711da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode, 2721da177e4SLinus Torvalds .destroy_inode = hostfs_destroy_inode, 273e971a6d7SAl Viro .evict_inode = hostfs_evict_inode, 2741da177e4SLinus Torvalds .statfs = hostfs_statfs, 275dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options, 2761da177e4SLinus Torvalds }; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds int hostfs_readdir(struct file *file, void *ent, filldir_t filldir) 2791da177e4SLinus Torvalds { 2801da177e4SLinus Torvalds void *dir; 2811da177e4SLinus Torvalds char *name; 2821da177e4SLinus Torvalds unsigned long long next, ino; 2831da177e4SLinus Torvalds int error, len; 2841da177e4SLinus Torvalds 285c5322220SAl Viro name = dentry_name(file->f_path.dentry); 286f1adc05eSJeff Dike if (name == NULL) 287f1adc05eSJeff Dike return -ENOMEM; 2881da177e4SLinus Torvalds dir = open_dir(name, &error); 289e9193059SAl Viro __putname(name); 290f1adc05eSJeff Dike if (dir == NULL) 291f1adc05eSJeff Dike return -error; 2921da177e4SLinus Torvalds next = file->f_pos; 2931da177e4SLinus Torvalds while ((name = read_dir(dir, &next, &ino, &len)) != NULL) { 2941da177e4SLinus Torvalds error = (*filldir)(ent, name, len, file->f_pos, 2951da177e4SLinus Torvalds ino, DT_UNKNOWN); 2961da177e4SLinus Torvalds if (error) break; 2971da177e4SLinus Torvalds file->f_pos = next; 2981da177e4SLinus Torvalds } 2991da177e4SLinus Torvalds close_dir(dir); 300f1adc05eSJeff Dike return 0; 3011da177e4SLinus Torvalds } 3021da177e4SLinus Torvalds 3031da177e4SLinus Torvalds int hostfs_file_open(struct inode *ino, struct file *file) 3041da177e4SLinus Torvalds { 3051da177e4SLinus Torvalds char *name; 306aeb5d727SAl Viro fmode_t mode = 0; 307aeb5d727SAl Viro int r = 0, w = 0, fd; 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE); 3101da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode) 311f1adc05eSJeff Dike return 0; 3121da177e4SLinus Torvalds 31384b3db04SJeff Dike /* 31484b3db04SJeff Dike * The file may already have been opened, but with the wrong access, 3151da177e4SLinus Torvalds * so this resets things and reopens the file with the new access. 3161da177e4SLinus Torvalds */ 3171da177e4SLinus Torvalds if (HOSTFS_I(ino)->fd != -1) { 3181da177e4SLinus Torvalds close_file(&HOSTFS_I(ino)->fd); 3191da177e4SLinus Torvalds HOSTFS_I(ino)->fd = -1; 3201da177e4SLinus Torvalds } 3211da177e4SLinus Torvalds 3221da177e4SLinus Torvalds HOSTFS_I(ino)->mode |= mode; 3231da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_READ) 3241da177e4SLinus Torvalds r = 1; 3251da177e4SLinus Torvalds if (HOSTFS_I(ino)->mode & FMODE_WRITE) 3261da177e4SLinus Torvalds w = 1; 3271da177e4SLinus Torvalds if (w) 3281da177e4SLinus Torvalds r = 1; 3291da177e4SLinus Torvalds 330c5322220SAl Viro name = dentry_name(file->f_path.dentry); 3311da177e4SLinus Torvalds if (name == NULL) 332f1adc05eSJeff Dike return -ENOMEM; 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds fd = open_file(name, r, w, append); 335e9193059SAl Viro __putname(name); 336f1adc05eSJeff Dike if (fd < 0) 337f1adc05eSJeff Dike return fd; 3381da177e4SLinus Torvalds FILE_HOSTFS_I(file)->fd = fd; 3391da177e4SLinus Torvalds 340f1adc05eSJeff Dike return 0; 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds 3437ea80859SChristoph Hellwig int hostfs_fsync(struct file *file, int datasync) 3441da177e4SLinus Torvalds { 3457ea80859SChristoph Hellwig return fsync_file(HOSTFS_I(file->f_mapping->host)->fd, datasync); 3461da177e4SLinus Torvalds } 3471da177e4SLinus Torvalds 3484b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = { 3491da177e4SLinus Torvalds .llseek = generic_file_llseek, 350543ade1fSBadari Pulavarty .read = do_sync_read, 3515ffc4ef4SJens Axboe .splice_read = generic_file_splice_read, 3521da177e4SLinus Torvalds .aio_read = generic_file_aio_read, 3531da177e4SLinus Torvalds .aio_write = generic_file_aio_write, 354543ade1fSBadari Pulavarty .write = do_sync_write, 3551da177e4SLinus Torvalds .mmap = generic_file_mmap, 3561da177e4SLinus Torvalds .open = hostfs_file_open, 3571da177e4SLinus Torvalds .release = NULL, 3581da177e4SLinus Torvalds .fsync = hostfs_fsync, 3591da177e4SLinus Torvalds }; 3601da177e4SLinus Torvalds 3614b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = { 3621da177e4SLinus Torvalds .llseek = generic_file_llseek, 3631da177e4SLinus Torvalds .readdir = hostfs_readdir, 3641da177e4SLinus Torvalds .read = generic_read_dir, 3651da177e4SLinus Torvalds }; 3661da177e4SLinus Torvalds 3671da177e4SLinus Torvalds int hostfs_writepage(struct page *page, struct writeback_control *wbc) 3681da177e4SLinus Torvalds { 3691da177e4SLinus Torvalds struct address_space *mapping = page->mapping; 3701da177e4SLinus Torvalds struct inode *inode = mapping->host; 3711da177e4SLinus Torvalds char *buffer; 3721da177e4SLinus Torvalds unsigned long long base; 3731da177e4SLinus Torvalds int count = PAGE_CACHE_SIZE; 3741da177e4SLinus Torvalds int end_index = inode->i_size >> PAGE_CACHE_SHIFT; 3751da177e4SLinus Torvalds int err; 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds if (page->index >= end_index) 3781da177e4SLinus Torvalds count = inode->i_size & (PAGE_CACHE_SIZE-1); 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds buffer = kmap(page); 3811da177e4SLinus Torvalds base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT; 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count); 3841da177e4SLinus Torvalds if (err != count) { 3851da177e4SLinus Torvalds ClearPageUptodate(page); 3861da177e4SLinus Torvalds goto out; 3871da177e4SLinus Torvalds } 3881da177e4SLinus Torvalds 3891da177e4SLinus Torvalds if (base > inode->i_size) 3901da177e4SLinus Torvalds inode->i_size = base; 3911da177e4SLinus Torvalds 3921da177e4SLinus Torvalds if (PageError(page)) 3931da177e4SLinus Torvalds ClearPageError(page); 3941da177e4SLinus Torvalds err = 0; 3951da177e4SLinus Torvalds 3961da177e4SLinus Torvalds out: 3971da177e4SLinus Torvalds kunmap(page); 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds unlock_page(page); 4001da177e4SLinus Torvalds return err; 4011da177e4SLinus Torvalds } 4021da177e4SLinus Torvalds 4031da177e4SLinus Torvalds int hostfs_readpage(struct file *file, struct page *page) 4041da177e4SLinus Torvalds { 4051da177e4SLinus Torvalds char *buffer; 4061da177e4SLinus Torvalds long long start; 4071da177e4SLinus Torvalds int err = 0; 4081da177e4SLinus Torvalds 4091da177e4SLinus Torvalds start = (long long) page->index << PAGE_CACHE_SHIFT; 4101da177e4SLinus Torvalds buffer = kmap(page); 4111da177e4SLinus Torvalds err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer, 4121da177e4SLinus Torvalds PAGE_CACHE_SIZE); 41384b3db04SJeff Dike if (err < 0) 41484b3db04SJeff Dike goto out; 4151da177e4SLinus Torvalds 4161da177e4SLinus Torvalds memset(&buffer[err], 0, PAGE_CACHE_SIZE - err); 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds flush_dcache_page(page); 4191da177e4SLinus Torvalds SetPageUptodate(page); 4201da177e4SLinus Torvalds if (PageError(page)) ClearPageError(page); 4211da177e4SLinus Torvalds err = 0; 4221da177e4SLinus Torvalds out: 4231da177e4SLinus Torvalds kunmap(page); 4241da177e4SLinus Torvalds unlock_page(page); 425f1adc05eSJeff Dike return err; 4261da177e4SLinus Torvalds } 4271da177e4SLinus Torvalds 428ae361ff4SNick Piggin int hostfs_write_begin(struct file *file, struct address_space *mapping, 429ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned flags, 430ae361ff4SNick Piggin struct page **pagep, void **fsdata) 4311da177e4SLinus Torvalds { 432ae361ff4SNick Piggin pgoff_t index = pos >> PAGE_CACHE_SHIFT; 433ae361ff4SNick Piggin 43454566b2cSNick Piggin *pagep = grab_cache_page_write_begin(mapping, index, flags); 435ae361ff4SNick Piggin if (!*pagep) 436ae361ff4SNick Piggin return -ENOMEM; 437ae361ff4SNick Piggin return 0; 438ae361ff4SNick Piggin } 439ae361ff4SNick Piggin 440ae361ff4SNick Piggin int hostfs_write_end(struct file *file, struct address_space *mapping, 441ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied, 442ae361ff4SNick Piggin struct page *page, void *fsdata) 443ae361ff4SNick Piggin { 444ae361ff4SNick Piggin struct inode *inode = mapping->host; 445ae361ff4SNick Piggin void *buffer; 446ae361ff4SNick Piggin unsigned from = pos & (PAGE_CACHE_SIZE - 1); 4471da177e4SLinus Torvalds int err; 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds buffer = kmap(page); 450ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied); 4511da177e4SLinus Torvalds kunmap(page); 4521da177e4SLinus Torvalds 453ae361ff4SNick Piggin if (!PageUptodate(page) && err == PAGE_CACHE_SIZE) 454ae361ff4SNick Piggin SetPageUptodate(page); 4551da177e4SLinus Torvalds 45684b3db04SJeff Dike /* 45784b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing 458ae361ff4SNick Piggin * i_size against the last byte written. 459ae361ff4SNick Piggin */ 460ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size)) 461ae361ff4SNick Piggin inode->i_size = pos; 462ae361ff4SNick Piggin unlock_page(page); 463ae361ff4SNick Piggin page_cache_release(page); 46430f04a4eSPaolo 'Blaisorblade' Giarrusso 465f1adc05eSJeff Dike return err; 4661da177e4SLinus Torvalds } 4671da177e4SLinus Torvalds 468f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = { 4691da177e4SLinus Torvalds .writepage = hostfs_writepage, 4701da177e4SLinus Torvalds .readpage = hostfs_readpage, 471ffa0aea6SPaolo 'Blaisorblade' Giarrusso .set_page_dirty = __set_page_dirty_nobuffers, 472ae361ff4SNick Piggin .write_begin = hostfs_write_begin, 473ae361ff4SNick Piggin .write_end = hostfs_write_end, 4741da177e4SLinus Torvalds }; 4751da177e4SLinus Torvalds 4764754b825SAl Viro static int read_name(struct inode *ino, char *name) 4771da177e4SLinus Torvalds { 4784754b825SAl Viro dev_t rdev; 4794754b825SAl Viro struct hostfs_stat st; 4804754b825SAl Viro int err = stat_file(name, &st, -1); 4814754b825SAl Viro if (err) 4824754b825SAl Viro return err; 4831da177e4SLinus Torvalds 4841da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/ 4854754b825SAl Viro rdev = MKDEV(st.maj, st.min); 4861da177e4SLinus Torvalds 4874754b825SAl Viro switch (st.mode & S_IFMT) { 4884754b825SAl Viro case S_IFLNK: 489d0352d3eSAl Viro ino->i_op = &hostfs_link_iops; 4904754b825SAl Viro break; 4914754b825SAl Viro case S_IFDIR: 4924754b825SAl Viro ino->i_op = &hostfs_dir_iops; 4934754b825SAl Viro ino->i_fop = &hostfs_dir_fops; 4944754b825SAl Viro break; 4954754b825SAl Viro case S_IFCHR: 4964754b825SAl Viro case S_IFBLK: 4974754b825SAl Viro case S_IFIFO: 4984754b825SAl Viro case S_IFSOCK: 4994754b825SAl Viro init_special_inode(ino, st.mode & S_IFMT, rdev); 5004754b825SAl Viro ino->i_op = &hostfs_iops; 5014754b825SAl Viro break; 5021da177e4SLinus Torvalds 5034754b825SAl Viro default: 5044754b825SAl Viro ino->i_op = &hostfs_iops; 5054754b825SAl Viro ino->i_fop = &hostfs_file_fops; 5064754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops; 5071da177e4SLinus Torvalds } 5084754b825SAl Viro 5094754b825SAl Viro ino->i_ino = st.ino; 5104754b825SAl Viro ino->i_mode = st.mode; 5114754b825SAl Viro ino->i_nlink = st.nlink; 5124754b825SAl Viro ino->i_uid = st.uid; 5134754b825SAl Viro ino->i_gid = st.gid; 5144754b825SAl Viro ino->i_atime = st.atime; 5154754b825SAl Viro ino->i_mtime = st.mtime; 5164754b825SAl Viro ino->i_ctime = st.ctime; 5174754b825SAl Viro ino->i_size = st.size; 5184754b825SAl Viro ino->i_blocks = st.blocks; 5194754b825SAl Viro return 0; 5201da177e4SLinus Torvalds } 5211da177e4SLinus Torvalds 5221da177e4SLinus Torvalds int hostfs_create(struct inode *dir, struct dentry *dentry, int mode, 5231da177e4SLinus Torvalds struct nameidata *nd) 5241da177e4SLinus Torvalds { 5251da177e4SLinus Torvalds struct inode *inode; 5261da177e4SLinus Torvalds char *name; 5271da177e4SLinus Torvalds int error, fd; 5281da177e4SLinus Torvalds 5290a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 5300a370e5dSDavid Howells if (IS_ERR(inode)) { 5310a370e5dSDavid Howells error = PTR_ERR(inode); 53284b3db04SJeff Dike goto out; 5330a370e5dSDavid Howells } 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds error = -ENOMEM; 536c5322220SAl Viro name = dentry_name(dentry); 5371da177e4SLinus Torvalds if (name == NULL) 5381da177e4SLinus Torvalds goto out_put; 5391da177e4SLinus Torvalds 5401da177e4SLinus Torvalds fd = file_create(name, 5411da177e4SLinus Torvalds mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR, 5421da177e4SLinus Torvalds mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP, 5431da177e4SLinus Torvalds mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH); 5444754b825SAl Viro if (fd < 0) 5451da177e4SLinus Torvalds error = fd; 5464754b825SAl Viro else 5475e2df28cSAl Viro error = read_name(inode, name); 5481da177e4SLinus Torvalds 549e9193059SAl Viro __putname(name); 5501da177e4SLinus Torvalds if (error) 5511da177e4SLinus Torvalds goto out_put; 5521da177e4SLinus Torvalds 5531da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd; 5541da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE; 5551da177e4SLinus Torvalds d_instantiate(dentry, inode); 556f1adc05eSJeff Dike return 0; 5571da177e4SLinus Torvalds 5581da177e4SLinus Torvalds out_put: 5591da177e4SLinus Torvalds iput(inode); 5601da177e4SLinus Torvalds out: 561f1adc05eSJeff Dike return error; 5621da177e4SLinus Torvalds } 5631da177e4SLinus Torvalds 5641da177e4SLinus Torvalds struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry, 5651da177e4SLinus Torvalds struct nameidata *nd) 5661da177e4SLinus Torvalds { 5671da177e4SLinus Torvalds struct inode *inode; 5681da177e4SLinus Torvalds char *name; 5691da177e4SLinus Torvalds int err; 5701da177e4SLinus Torvalds 5710a370e5dSDavid Howells inode = hostfs_iget(ino->i_sb); 5720a370e5dSDavid Howells if (IS_ERR(inode)) { 5730a370e5dSDavid Howells err = PTR_ERR(inode); 5741da177e4SLinus Torvalds goto out; 5750a370e5dSDavid Howells } 5761da177e4SLinus Torvalds 5771da177e4SLinus Torvalds err = -ENOMEM; 578c5322220SAl Viro name = dentry_name(dentry); 5791da177e4SLinus Torvalds if (name == NULL) 5801da177e4SLinus Torvalds goto out_put; 5811da177e4SLinus Torvalds 5821da177e4SLinus Torvalds err = read_name(inode, name); 5835e2df28cSAl Viro 584e9193059SAl Viro __putname(name); 5851da177e4SLinus Torvalds if (err == -ENOENT) { 5861da177e4SLinus Torvalds iput(inode); 5871da177e4SLinus Torvalds inode = NULL; 5881da177e4SLinus Torvalds } 5891da177e4SLinus Torvalds else if (err) 5901da177e4SLinus Torvalds goto out_put; 5911da177e4SLinus Torvalds 5921da177e4SLinus Torvalds d_add(dentry, inode); 5931da177e4SLinus Torvalds dentry->d_op = &hostfs_dentry_ops; 594f1adc05eSJeff Dike return NULL; 5951da177e4SLinus Torvalds 5961da177e4SLinus Torvalds out_put: 5971da177e4SLinus Torvalds iput(inode); 5981da177e4SLinus Torvalds out: 599f1adc05eSJeff Dike return ERR_PTR(err); 6001da177e4SLinus Torvalds } 6011da177e4SLinus Torvalds 6021da177e4SLinus Torvalds int hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from) 6031da177e4SLinus Torvalds { 6041da177e4SLinus Torvalds char *from_name, *to_name; 6051da177e4SLinus Torvalds int err; 6061da177e4SLinus Torvalds 607c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 608f1adc05eSJeff Dike return -ENOMEM; 609c5322220SAl Viro to_name = dentry_name(to); 6101da177e4SLinus Torvalds if (to_name == NULL) { 611e9193059SAl Viro __putname(from_name); 612f1adc05eSJeff Dike return -ENOMEM; 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds err = link_file(to_name, from_name); 615e9193059SAl Viro __putname(from_name); 616e9193059SAl Viro __putname(to_name); 617f1adc05eSJeff Dike return err; 6181da177e4SLinus Torvalds } 6191da177e4SLinus Torvalds 6201da177e4SLinus Torvalds int hostfs_unlink(struct inode *ino, struct dentry *dentry) 6211da177e4SLinus Torvalds { 6221da177e4SLinus Torvalds char *file; 6231da177e4SLinus Torvalds int err; 6241da177e4SLinus Torvalds 6251da177e4SLinus Torvalds if (append) 626f1adc05eSJeff Dike return -EPERM; 6271da177e4SLinus Torvalds 628f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL) 629f8d7e187SAl Viro return -ENOMEM; 630f8d7e187SAl Viro 6311da177e4SLinus Torvalds err = unlink_file(file); 632e9193059SAl Viro __putname(file); 633f1adc05eSJeff Dike return err; 6341da177e4SLinus Torvalds } 6351da177e4SLinus Torvalds 6361da177e4SLinus Torvalds int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to) 6371da177e4SLinus Torvalds { 6381da177e4SLinus Torvalds char *file; 6391da177e4SLinus Torvalds int err; 6401da177e4SLinus Torvalds 641c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 642f1adc05eSJeff Dike return -ENOMEM; 6431da177e4SLinus Torvalds err = make_symlink(file, to); 644e9193059SAl Viro __putname(file); 645f1adc05eSJeff Dike return err; 6461da177e4SLinus Torvalds } 6471da177e4SLinus Torvalds 6481da177e4SLinus Torvalds int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode) 6491da177e4SLinus Torvalds { 6501da177e4SLinus Torvalds char *file; 6511da177e4SLinus Torvalds int err; 6521da177e4SLinus Torvalds 653c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 654f1adc05eSJeff Dike return -ENOMEM; 6551da177e4SLinus Torvalds err = do_mkdir(file, mode); 656e9193059SAl Viro __putname(file); 657f1adc05eSJeff Dike return err; 6581da177e4SLinus Torvalds } 6591da177e4SLinus Torvalds 6601da177e4SLinus Torvalds int hostfs_rmdir(struct inode *ino, struct dentry *dentry) 6611da177e4SLinus Torvalds { 6621da177e4SLinus Torvalds char *file; 6631da177e4SLinus Torvalds int err; 6641da177e4SLinus Torvalds 665c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL) 666f1adc05eSJeff Dike return -ENOMEM; 6671da177e4SLinus Torvalds err = do_rmdir(file); 668e9193059SAl Viro __putname(file); 669f1adc05eSJeff Dike return err; 6701da177e4SLinus Torvalds } 6711da177e4SLinus Torvalds 6721da177e4SLinus Torvalds int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 6731da177e4SLinus Torvalds { 6741da177e4SLinus Torvalds struct inode *inode; 6751da177e4SLinus Torvalds char *name; 6760a370e5dSDavid Howells int err; 6771da177e4SLinus Torvalds 6780a370e5dSDavid Howells inode = hostfs_iget(dir->i_sb); 6790a370e5dSDavid Howells if (IS_ERR(inode)) { 6800a370e5dSDavid Howells err = PTR_ERR(inode); 6811da177e4SLinus Torvalds goto out; 6820a370e5dSDavid Howells } 6831da177e4SLinus Torvalds 6841da177e4SLinus Torvalds err = -ENOMEM; 685c5322220SAl Viro name = dentry_name(dentry); 6861da177e4SLinus Torvalds if (name == NULL) 6871da177e4SLinus Torvalds goto out_put; 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds init_special_inode(inode, mode, dev); 69088f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev)); 691e9193059SAl Viro if (!err) 6921da177e4SLinus Torvalds goto out_free; 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvalds err = read_name(inode, name); 695e9193059SAl Viro __putname(name); 6965e2df28cSAl Viro if (err) 6975e2df28cSAl Viro goto out_put; 6981da177e4SLinus Torvalds if (err) 6991da177e4SLinus Torvalds goto out_put; 7001da177e4SLinus Torvalds 7011da177e4SLinus Torvalds d_instantiate(dentry, inode); 702f1adc05eSJeff Dike return 0; 7031da177e4SLinus Torvalds 7041da177e4SLinus Torvalds out_free: 705e9193059SAl Viro __putname(name); 7061da177e4SLinus Torvalds out_put: 7071da177e4SLinus Torvalds iput(inode); 7081da177e4SLinus Torvalds out: 709f1adc05eSJeff Dike return err; 7101da177e4SLinus Torvalds } 7111da177e4SLinus Torvalds 7121da177e4SLinus Torvalds int hostfs_rename(struct inode *from_ino, struct dentry *from, 7131da177e4SLinus Torvalds struct inode *to_ino, struct dentry *to) 7141da177e4SLinus Torvalds { 7151da177e4SLinus Torvalds char *from_name, *to_name; 7161da177e4SLinus Torvalds int err; 7171da177e4SLinus Torvalds 718c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL) 719f1adc05eSJeff Dike return -ENOMEM; 720c5322220SAl Viro if ((to_name = dentry_name(to)) == NULL) { 721e9193059SAl Viro __putname(from_name); 722f1adc05eSJeff Dike return -ENOMEM; 7231da177e4SLinus Torvalds } 7241da177e4SLinus Torvalds err = rename_file(from_name, to_name); 725e9193059SAl Viro __putname(from_name); 726e9193059SAl Viro __putname(to_name); 727f1adc05eSJeff Dike return err; 7281da177e4SLinus Torvalds } 7291da177e4SLinus Torvalds 730e6305c43SAl Viro int hostfs_permission(struct inode *ino, int desired) 7311da177e4SLinus Torvalds { 7321da177e4SLinus Torvalds char *name; 7331da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err; 7341da177e4SLinus Torvalds 7351da177e4SLinus Torvalds if (desired & MAY_READ) r = 1; 7361da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1; 7371da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1; 738c5322220SAl Viro name = inode_name(ino); 739f1adc05eSJeff Dike if (name == NULL) 740f1adc05eSJeff Dike return -ENOMEM; 7411da177e4SLinus Torvalds 7421da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) || 7431da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode)) 7441da177e4SLinus Torvalds err = 0; 7451da177e4SLinus Torvalds else 7461da177e4SLinus Torvalds err = access_file(name, r, w, x); 747e9193059SAl Viro __putname(name); 7481da177e4SLinus Torvalds if (!err) 7491da177e4SLinus Torvalds err = generic_permission(ino, desired, NULL); 7501da177e4SLinus Torvalds return err; 7511da177e4SLinus Torvalds } 7521da177e4SLinus Torvalds 7531da177e4SLinus Torvalds int hostfs_setattr(struct dentry *dentry, struct iattr *attr) 7541da177e4SLinus Torvalds { 7551025774cSChristoph Hellwig struct inode *inode = dentry->d_inode; 7561da177e4SLinus Torvalds struct hostfs_iattr attrs; 7571da177e4SLinus Torvalds char *name; 7581da177e4SLinus Torvalds int err; 7591da177e4SLinus Torvalds 7601025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd; 7615822b7faSAlberto Bertogli 7621025774cSChristoph Hellwig err = inode_change_ok(inode, attr); 7631da177e4SLinus Torvalds if (err) 7641da177e4SLinus Torvalds return err; 7651da177e4SLinus Torvalds 7661da177e4SLinus Torvalds if (append) 7671da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE; 7681da177e4SLinus Torvalds 7691da177e4SLinus Torvalds attrs.ia_valid = 0; 7701da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) { 7711da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE; 7721da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode; 7731da177e4SLinus Torvalds } 7741da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) { 7751da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID; 7761da177e4SLinus Torvalds attrs.ia_uid = attr->ia_uid; 7771da177e4SLinus Torvalds } 7781da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) { 7791da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID; 7801da177e4SLinus Torvalds attrs.ia_gid = attr->ia_gid; 7811da177e4SLinus Torvalds } 7821da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) { 7831da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE; 7841da177e4SLinus Torvalds attrs.ia_size = attr->ia_size; 7851da177e4SLinus Torvalds } 7861da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) { 7871da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME; 7881da177e4SLinus Torvalds attrs.ia_atime = attr->ia_atime; 7891da177e4SLinus Torvalds } 7901da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) { 7911da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME; 7921da177e4SLinus Torvalds attrs.ia_mtime = attr->ia_mtime; 7931da177e4SLinus Torvalds } 7941da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) { 7951da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME; 7961da177e4SLinus Torvalds attrs.ia_ctime = attr->ia_ctime; 7971da177e4SLinus Torvalds } 7981da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) { 7991da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET; 8001da177e4SLinus Torvalds } 8011da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) { 8021da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET; 8031da177e4SLinus Torvalds } 804c5322220SAl Viro name = dentry_name(dentry); 805f1adc05eSJeff Dike if (name == NULL) 806f1adc05eSJeff Dike return -ENOMEM; 8075822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd); 808e9193059SAl Viro __putname(name); 8091da177e4SLinus Torvalds if (err) 810f1adc05eSJeff Dike return err; 8111da177e4SLinus Torvalds 8121025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) && 8131025774cSChristoph Hellwig attr->ia_size != i_size_read(inode)) { 8141025774cSChristoph Hellwig int error; 8151025774cSChristoph Hellwig 8161025774cSChristoph Hellwig error = vmtruncate(inode, attr->ia_size); 8171025774cSChristoph Hellwig if (err) 8181025774cSChristoph Hellwig return err; 8191025774cSChristoph Hellwig } 8201025774cSChristoph Hellwig 8211025774cSChristoph Hellwig setattr_copy(inode, attr); 8221025774cSChristoph Hellwig mark_inode_dirty(inode); 8231025774cSChristoph Hellwig return 0; 8241da177e4SLinus Torvalds } 8251da177e4SLinus Torvalds 82692e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = { 8271da177e4SLinus Torvalds .create = hostfs_create, 8281da177e4SLinus Torvalds .link = hostfs_link, 8291da177e4SLinus Torvalds .unlink = hostfs_unlink, 8301da177e4SLinus Torvalds .symlink = hostfs_symlink, 8311da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8321da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8331da177e4SLinus Torvalds .mknod = hostfs_mknod, 8341da177e4SLinus Torvalds .rename = hostfs_rename, 8351da177e4SLinus Torvalds .permission = hostfs_permission, 8361da177e4SLinus Torvalds .setattr = hostfs_setattr, 8371da177e4SLinus Torvalds }; 8381da177e4SLinus Torvalds 83992e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = { 8401da177e4SLinus Torvalds .create = hostfs_create, 8411da177e4SLinus Torvalds .lookup = hostfs_lookup, 8421da177e4SLinus Torvalds .link = hostfs_link, 8431da177e4SLinus Torvalds .unlink = hostfs_unlink, 8441da177e4SLinus Torvalds .symlink = hostfs_symlink, 8451da177e4SLinus Torvalds .mkdir = hostfs_mkdir, 8461da177e4SLinus Torvalds .rmdir = hostfs_rmdir, 8471da177e4SLinus Torvalds .mknod = hostfs_mknod, 8481da177e4SLinus Torvalds .rename = hostfs_rename, 8491da177e4SLinus Torvalds .permission = hostfs_permission, 8501da177e4SLinus Torvalds .setattr = hostfs_setattr, 8511da177e4SLinus Torvalds }; 8521da177e4SLinus Torvalds 853d0352d3eSAl Viro static void *hostfs_follow_link(struct dentry *dentry, struct nameidata *nd) 8541da177e4SLinus Torvalds { 855d0352d3eSAl Viro char *link = __getname(); 856d0352d3eSAl Viro if (link) { 857d0352d3eSAl Viro char *path = dentry_name(dentry); 858d0352d3eSAl Viro int err = -ENOMEM; 859d0352d3eSAl Viro if (path) { 860d0352d3eSAl Viro int err = hostfs_do_readlink(path, link, PATH_MAX); 861d0352d3eSAl Viro if (err == PATH_MAX) 8621da177e4SLinus Torvalds err = -E2BIG; 863e9193059SAl Viro __putname(path); 8641da177e4SLinus Torvalds } 865d0352d3eSAl Viro if (err < 0) { 866d0352d3eSAl Viro __putname(link); 867d0352d3eSAl Viro link = ERR_PTR(err); 868d0352d3eSAl Viro } 869d0352d3eSAl Viro } else { 870d0352d3eSAl Viro link = ERR_PTR(-ENOMEM); 8711da177e4SLinus Torvalds } 8721da177e4SLinus Torvalds 873d0352d3eSAl Viro nd_set_link(nd, link); 874d0352d3eSAl Viro return NULL; 875d0352d3eSAl Viro } 876d0352d3eSAl Viro 877d0352d3eSAl Viro static void hostfs_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 878d0352d3eSAl Viro { 879d0352d3eSAl Viro char *s = nd_get_link(nd); 880d0352d3eSAl Viro if (!IS_ERR(s)) 881d0352d3eSAl Viro __putname(s); 882d0352d3eSAl Viro } 883d0352d3eSAl Viro 884d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = { 885d0352d3eSAl Viro .readlink = generic_readlink, 886d0352d3eSAl Viro .follow_link = hostfs_follow_link, 887d0352d3eSAl Viro .put_link = hostfs_put_link, 8881da177e4SLinus Torvalds }; 8891da177e4SLinus Torvalds 8901da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent) 8911da177e4SLinus Torvalds { 8921da177e4SLinus Torvalds struct inode *root_inode; 89375e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d; 8941da177e4SLinus Torvalds int err; 8951da177e4SLinus Torvalds 8961da177e4SLinus Torvalds sb->s_blocksize = 1024; 8971da177e4SLinus Torvalds sb->s_blocksize_bits = 10; 8981da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC; 8991da177e4SLinus Torvalds sb->s_op = &hostfs_sbops; 900752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE; 9011da177e4SLinus Torvalds 902a6eb0be6SPaolo 'Blaisorblade' Giarrusso /* NULL is printed as <NULL> by sprintf: avoid that. */ 90375e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL) 90475e8defbSPaolo 'Blaisorblade' Giarrusso req_root = ""; 9051da177e4SLinus Torvalds 9061da177e4SLinus Torvalds err = -ENOMEM; 907601d2c38SAl Viro sb->s_fs_info = host_root_path = 908601d2c38SAl Viro kmalloc(strlen(root_ino) + strlen(req_root) + 2, GFP_KERNEL); 90975e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL) 9101da177e4SLinus Torvalds goto out; 9111da177e4SLinus Torvalds 91275e8defbSPaolo 'Blaisorblade' Giarrusso sprintf(host_root_path, "%s/%s", root_ino, req_root); 9131da177e4SLinus Torvalds 91452b209f7SAl Viro root_inode = new_inode(sb); 91552b209f7SAl Viro if (!root_inode) 916601d2c38SAl Viro goto out; 9171da177e4SLinus Torvalds 9184754b825SAl Viro err = read_name(root_inode, host_root_path); 9194754b825SAl Viro if (err) 9204754b825SAl Viro goto out_put; 92152b209f7SAl Viro 9224754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) { 92352b209f7SAl Viro char *name = follow_link(host_root_path); 92452b209f7SAl Viro if (IS_ERR(name)) 92552b209f7SAl Viro err = PTR_ERR(name); 92652b209f7SAl Viro else 92752b209f7SAl Viro err = read_name(root_inode, name); 92852b209f7SAl Viro kfree(name); 9291da177e4SLinus Torvalds if (err) 9301da177e4SLinus Torvalds goto out_put; 9314754b825SAl Viro } 9321da177e4SLinus Torvalds 9331da177e4SLinus Torvalds err = -ENOMEM; 9341da177e4SLinus Torvalds sb->s_root = d_alloc_root(root_inode); 9351da177e4SLinus Torvalds if (sb->s_root == NULL) 9361da177e4SLinus Torvalds goto out_put; 9371da177e4SLinus Torvalds 938f1adc05eSJeff Dike return 0; 9391da177e4SLinus Torvalds 9401da177e4SLinus Torvalds out_put: 9411da177e4SLinus Torvalds iput(root_inode); 9421da177e4SLinus Torvalds out: 943f1adc05eSJeff Dike return err; 9441da177e4SLinus Torvalds } 9451da177e4SLinus Torvalds 946454e2398SDavid Howells static int hostfs_read_sb(struct file_system_type *type, 9471da177e4SLinus Torvalds int flags, const char *dev_name, 948454e2398SDavid Howells void *data, struct vfsmount *mnt) 9491da177e4SLinus Torvalds { 950454e2398SDavid Howells return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt); 9511da177e4SLinus Torvalds } 9521da177e4SLinus Torvalds 953601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s) 954601d2c38SAl Viro { 955601d2c38SAl Viro kill_anon_super(s); 956601d2c38SAl Viro kfree(s->s_fs_info); 957601d2c38SAl Viro } 958601d2c38SAl Viro 9591da177e4SLinus Torvalds static struct file_system_type hostfs_type = { 9601da177e4SLinus Torvalds .owner = THIS_MODULE, 9611da177e4SLinus Torvalds .name = "hostfs", 9621da177e4SLinus Torvalds .get_sb = hostfs_read_sb, 963601d2c38SAl Viro .kill_sb = hostfs_kill_sb, 9641da177e4SLinus Torvalds .fs_flags = 0, 9651da177e4SLinus Torvalds }; 9661da177e4SLinus Torvalds 9671da177e4SLinus Torvalds static int __init init_hostfs(void) 9681da177e4SLinus Torvalds { 969f1adc05eSJeff Dike return register_filesystem(&hostfs_type); 9701da177e4SLinus Torvalds } 9711da177e4SLinus Torvalds 9721da177e4SLinus Torvalds static void __exit exit_hostfs(void) 9731da177e4SLinus Torvalds { 9741da177e4SLinus Torvalds unregister_filesystem(&hostfs_type); 9751da177e4SLinus Torvalds } 9761da177e4SLinus Torvalds 9771da177e4SLinus Torvalds module_init(init_hostfs) 9781da177e4SLinus Torvalds module_exit(exit_hostfs) 9791da177e4SLinus Torvalds MODULE_LICENSE("GPL"); 980