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>
102b3b9bb0SJames Hogan #include <linux/magic.h>
111da177e4SLinus Torvalds #include <linux/module.h>
1284b3db04SJeff Dike #include <linux/mm.h>
131da177e4SLinus Torvalds #include <linux/pagemap.h>
141da177e4SLinus Torvalds #include <linux/statfs.h>
155a0e3ad6STejun Heo #include <linux/slab.h>
16dd2cc4dfSMiklos Szeredi #include <linux/seq_file.h>
17187c82cbSMatthew Wilcox (Oracle) #include <linux/writeback.h>
186966a977SJiri Kosina #include <linux/mount.h>
19d0352d3eSAl Viro #include <linux/namei.h>
201da177e4SLinus Torvalds #include "hostfs.h"
2137185b33SAl Viro #include <init.h>
2237185b33SAl Viro #include <kern.h>
231da177e4SLinus Torvalds
241da177e4SLinus Torvalds struct hostfs_inode_info {
251da177e4SLinus Torvalds int fd;
26aeb5d727SAl Viro fmode_t mode;
271da177e4SLinus Torvalds struct inode vfs_inode;
2869886e67SRichard Weinberger struct mutex open_mutex;
2974ce793bSMickaël Salaün dev_t dev;
301da177e4SLinus Torvalds };
311da177e4SLinus Torvalds
HOSTFS_I(struct inode * inode)321da177e4SLinus Torvalds static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
331da177e4SLinus Torvalds {
34f1adc05eSJeff Dike return list_entry(inode, struct hostfs_inode_info, vfs_inode);
351da177e4SLinus Torvalds }
361da177e4SLinus Torvalds
37496ad9aaSAl Viro #define FILE_HOSTFS_I(file) HOSTFS_I(file_inode(file))
381da177e4SLinus Torvalds
39a15f1e41SJohannes Berg static struct kmem_cache *hostfs_inode_cache;
40a15f1e41SJohannes Berg
411da177e4SLinus Torvalds /* Changed in hostfs_args before the kernel starts running */
42a6eb0be6SPaolo 'Blaisorblade' Giarrusso static char *root_ino = "";
431da177e4SLinus Torvalds static int append = 0;
441da177e4SLinus Torvalds
4592e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops;
4692e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops;
47d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops;
481da177e4SLinus Torvalds
491da177e4SLinus Torvalds #ifndef MODULE
hostfs_args(char * options,int * add)501da177e4SLinus Torvalds static int __init hostfs_args(char *options, int *add)
511da177e4SLinus Torvalds {
521da177e4SLinus Torvalds char *ptr;
531da177e4SLinus Torvalds
541da177e4SLinus Torvalds ptr = strchr(options, ',');
551da177e4SLinus Torvalds if (ptr != NULL)
561da177e4SLinus Torvalds *ptr++ = '\0';
571da177e4SLinus Torvalds if (*options != '\0')
581da177e4SLinus Torvalds root_ino = options;
591da177e4SLinus Torvalds
601da177e4SLinus Torvalds options = ptr;
611da177e4SLinus Torvalds while (options) {
621da177e4SLinus Torvalds ptr = strchr(options, ',');
631da177e4SLinus Torvalds if (ptr != NULL)
641da177e4SLinus Torvalds *ptr++ = '\0';
651da177e4SLinus Torvalds if (*options != '\0') {
661da177e4SLinus Torvalds if (!strcmp(options, "append"))
671da177e4SLinus Torvalds append = 1;
681da177e4SLinus Torvalds else printf("hostfs_args - unsupported option - %s\n",
691da177e4SLinus Torvalds options);
701da177e4SLinus Torvalds }
711da177e4SLinus Torvalds options = ptr;
721da177e4SLinus Torvalds }
73f1adc05eSJeff Dike return 0;
741da177e4SLinus Torvalds }
751da177e4SLinus Torvalds
761da177e4SLinus Torvalds __uml_setup("hostfs=", hostfs_args,
771da177e4SLinus Torvalds "hostfs=<root dir>,<flags>,...\n"
781da177e4SLinus Torvalds " This is used to set hostfs parameters. The root directory argument\n"
791da177e4SLinus Torvalds " is used to confine all hostfs mounts to within the specified directory\n"
801da177e4SLinus Torvalds " tree on the host. If this isn't specified, then a user inside UML can\n"
811da177e4SLinus Torvalds " mount anything on the host that's accessible to the user that's running\n"
821da177e4SLinus Torvalds " it.\n"
831da177e4SLinus Torvalds " The only flag currently supported is 'append', which specifies that all\n"
841da177e4SLinus Torvalds " files opened by hostfs will be opened in append mode.\n\n"
851da177e4SLinus Torvalds );
861da177e4SLinus Torvalds #endif
871da177e4SLinus Torvalds
__dentry_name(struct dentry * dentry,char * name)88e9193059SAl Viro static char *__dentry_name(struct dentry *dentry, char *name)
89e9193059SAl Viro {
90ec2447c2SNick Piggin char *p = dentry_path_raw(dentry, name, PATH_MAX);
91e9193059SAl Viro char *root;
92e9193059SAl Viro size_t len;
93e9193059SAl Viro
94e9193059SAl Viro root = dentry->d_sb->s_fs_info;
95e9193059SAl Viro len = strlen(root);
96e9193059SAl Viro if (IS_ERR(p)) {
97e9193059SAl Viro __putname(name);
98e9193059SAl Viro return NULL;
99e9193059SAl Viro }
100aad50b1eSRichard Weinberger
101aad50b1eSRichard Weinberger /*
102aad50b1eSRichard Weinberger * This function relies on the fact that dentry_path_raw() will place
103aad50b1eSRichard Weinberger * the path name at the end of the provided buffer.
104aad50b1eSRichard Weinberger */
105aad50b1eSRichard Weinberger BUG_ON(p + strlen(p) + 1 != name + PATH_MAX);
106aad50b1eSRichard Weinberger
107b7f28a37SWolfram Sang strscpy(name, root, PATH_MAX);
108e9193059SAl Viro if (len > p - name) {
109e9193059SAl Viro __putname(name);
110e9193059SAl Viro return NULL;
111e9193059SAl Viro }
112c278e81bSRichard Weinberger
113c278e81bSRichard Weinberger if (p > name + len)
114c278e81bSRichard Weinberger strcpy(name + len, p);
115c278e81bSRichard Weinberger
116e9193059SAl Viro return name;
117e9193059SAl Viro }
118e9193059SAl Viro
dentry_name(struct dentry * dentry)119c5322220SAl Viro static char *dentry_name(struct dentry *dentry)
1201da177e4SLinus Torvalds {
121e9193059SAl Viro char *name = __getname();
122e9193059SAl Viro if (!name)
123f1adc05eSJeff Dike return NULL;
1241da177e4SLinus Torvalds
1259dcc5e8aSJames Hogan return __dentry_name(dentry, name);
1261da177e4SLinus Torvalds }
1271da177e4SLinus Torvalds
inode_name(struct inode * ino)128c5322220SAl Viro static char *inode_name(struct inode *ino)
1291da177e4SLinus Torvalds {
1301da177e4SLinus Torvalds struct dentry *dentry;
131ec2447c2SNick Piggin char *name;
132ec2447c2SNick Piggin
133ec2447c2SNick Piggin dentry = d_find_alias(ino);
134ec2447c2SNick Piggin if (!dentry)
135e9193059SAl Viro return NULL;
1361da177e4SLinus Torvalds
137ec2447c2SNick Piggin name = dentry_name(dentry);
138ec2447c2SNick Piggin
139ec2447c2SNick Piggin dput(dentry);
140ec2447c2SNick Piggin
141ec2447c2SNick Piggin return name;
1421da177e4SLinus Torvalds }
1431da177e4SLinus Torvalds
follow_link(char * link)1441da177e4SLinus Torvalds static char *follow_link(char *link)
1451da177e4SLinus Torvalds {
1461da177e4SLinus Torvalds char *name, *resolved, *end;
147b58c4e96SAndy Shevchenko int n;
1481da177e4SLinus Torvalds
1497f6c411cSAl Viro name = kmalloc(PATH_MAX, GFP_KERNEL);
1507c950992SRichard Weinberger if (!name) {
1511da177e4SLinus Torvalds n = -ENOMEM;
1527c950992SRichard Weinberger goto out_free;
1531da177e4SLinus Torvalds }
1547c950992SRichard Weinberger
1557c950992SRichard Weinberger n = hostfs_do_readlink(link, name, PATH_MAX);
1561da177e4SLinus Torvalds if (n < 0)
1571da177e4SLinus Torvalds goto out_free;
1587c950992SRichard Weinberger else if (n == PATH_MAX) {
1597c950992SRichard Weinberger n = -E2BIG;
1607c950992SRichard Weinberger goto out_free;
1617c950992SRichard Weinberger }
1621da177e4SLinus Torvalds
1631da177e4SLinus Torvalds if (*name == '/')
164f1adc05eSJeff Dike return name;
1651da177e4SLinus Torvalds
1661da177e4SLinus Torvalds end = strrchr(link, '/');
1671da177e4SLinus Torvalds if (end == NULL)
168f1adc05eSJeff Dike return name;
1691da177e4SLinus Torvalds
1701da177e4SLinus Torvalds *(end + 1) = '\0';
1711da177e4SLinus Torvalds
172b58c4e96SAndy Shevchenko resolved = kasprintf(GFP_KERNEL, "%s%s", link, name);
1731da177e4SLinus Torvalds if (resolved == NULL) {
1741da177e4SLinus Torvalds n = -ENOMEM;
1751da177e4SLinus Torvalds goto out_free;
1761da177e4SLinus Torvalds }
1771da177e4SLinus Torvalds
1787f6c411cSAl Viro kfree(name);
179f1adc05eSJeff Dike return resolved;
1801da177e4SLinus Torvalds
1811da177e4SLinus Torvalds out_free:
1827f6c411cSAl Viro kfree(name);
183f1adc05eSJeff Dike return ERR_PTR(n);
1841da177e4SLinus Torvalds }
1851da177e4SLinus Torvalds
hostfs_statfs(struct dentry * dentry,struct kstatfs * sf)1869e443bc3SJames Hogan static int hostfs_statfs(struct dentry *dentry, struct kstatfs *sf)
1871da177e4SLinus Torvalds {
18884b3db04SJeff Dike /*
18984b3db04SJeff Dike * do_statfs uses struct statfs64 internally, but the linux kernel
1901da177e4SLinus Torvalds * struct statfs still has 32-bit versions for most of these fields,
1911da177e4SLinus Torvalds * so we convert them here
1921da177e4SLinus Torvalds */
1931da177e4SLinus Torvalds int err;
1941da177e4SLinus Torvalds long long f_blocks;
1951da177e4SLinus Torvalds long long f_bfree;
1961da177e4SLinus Torvalds long long f_bavail;
1971da177e4SLinus Torvalds long long f_files;
1981da177e4SLinus Torvalds long long f_ffree;
1991da177e4SLinus Torvalds
200601d2c38SAl Viro err = do_statfs(dentry->d_sb->s_fs_info,
2011da177e4SLinus Torvalds &sf->f_bsize, &f_blocks, &f_bfree, &f_bavail, &f_files,
2021da177e4SLinus Torvalds &f_ffree, &sf->f_fsid, sizeof(sf->f_fsid),
2031b627d57SRichard Weinberger &sf->f_namelen);
204f1adc05eSJeff Dike if (err)
205f1adc05eSJeff Dike return err;
2061da177e4SLinus Torvalds sf->f_blocks = f_blocks;
2071da177e4SLinus Torvalds sf->f_bfree = f_bfree;
2081da177e4SLinus Torvalds sf->f_bavail = f_bavail;
2091da177e4SLinus Torvalds sf->f_files = f_files;
2101da177e4SLinus Torvalds sf->f_ffree = f_ffree;
2111da177e4SLinus Torvalds sf->f_type = HOSTFS_SUPER_MAGIC;
212f1adc05eSJeff Dike return 0;
2131da177e4SLinus Torvalds }
2141da177e4SLinus Torvalds
hostfs_alloc_inode(struct super_block * sb)2151da177e4SLinus Torvalds static struct inode *hostfs_alloc_inode(struct super_block *sb)
2161da177e4SLinus Torvalds {
2171da177e4SLinus Torvalds struct hostfs_inode_info *hi;
2181da177e4SLinus Torvalds
219fd60b288SMuchun Song hi = alloc_inode_sb(sb, hostfs_inode_cache, GFP_KERNEL_ACCOUNT);
2201da177e4SLinus Torvalds if (hi == NULL)
221f1adc05eSJeff Dike return NULL;
222601d2c38SAl Viro hi->fd = -1;
223371fdab1SJames Hogan hi->mode = 0;
22474ce793bSMickaël Salaün hi->dev = 0;
2251da177e4SLinus Torvalds inode_init_once(&hi->vfs_inode);
22669886e67SRichard Weinberger mutex_init(&hi->open_mutex);
227f1adc05eSJeff Dike return &hi->vfs_inode;
2281da177e4SLinus Torvalds }
2291da177e4SLinus Torvalds
hostfs_evict_inode(struct inode * inode)230e971a6d7SAl Viro static void hostfs_evict_inode(struct inode *inode)
2311da177e4SLinus Torvalds {
23291b0abe3SJohannes Weiner truncate_inode_pages_final(&inode->i_data);
233dbd5768fSJan Kara clear_inode(inode);
2341da177e4SLinus Torvalds if (HOSTFS_I(inode)->fd != -1) {
2351da177e4SLinus Torvalds close_file(&HOSTFS_I(inode)->fd);
2361da177e4SLinus Torvalds HOSTFS_I(inode)->fd = -1;
23774ce793bSMickaël Salaün HOSTFS_I(inode)->dev = 0;
2381da177e4SLinus Torvalds }
2391da177e4SLinus Torvalds }
2401da177e4SLinus Torvalds
hostfs_free_inode(struct inode * inode)24108ccfc5cSAl Viro static void hostfs_free_inode(struct inode *inode)
242fa0d7e3dSNick Piggin {
243a15f1e41SJohannes Berg kmem_cache_free(hostfs_inode_cache, HOSTFS_I(inode));
244fa0d7e3dSNick Piggin }
245fa0d7e3dSNick Piggin
hostfs_show_options(struct seq_file * seq,struct dentry * root)24634c80b1dSAl Viro static int hostfs_show_options(struct seq_file *seq, struct dentry *root)
247dd2cc4dfSMiklos Szeredi {
24834c80b1dSAl Viro const char *root_path = root->d_sb->s_fs_info;
249dd2cc4dfSMiklos Szeredi size_t offset = strlen(root_ino) + 1;
250dd2cc4dfSMiklos Szeredi
251dd2cc4dfSMiklos Szeredi if (strlen(root_path) > offset)
252a068acf2SKees Cook seq_show_option(seq, root_path + offset, NULL);
253dd2cc4dfSMiklos Szeredi
2547f74a668SRichard Weinberger if (append)
2557f74a668SRichard Weinberger seq_puts(seq, ",append");
2567f74a668SRichard Weinberger
257dd2cc4dfSMiklos Szeredi return 0;
258dd2cc4dfSMiklos Szeredi }
259dd2cc4dfSMiklos Szeredi
260ee9b6d61SJosef 'Jeff' Sipek static const struct super_operations hostfs_sbops = {
2611da177e4SLinus Torvalds .alloc_inode = hostfs_alloc_inode,
26208ccfc5cSAl Viro .free_inode = hostfs_free_inode,
26374ce793bSMickaël Salaün .drop_inode = generic_delete_inode,
264e971a6d7SAl Viro .evict_inode = hostfs_evict_inode,
2651da177e4SLinus Torvalds .statfs = hostfs_statfs,
266dd2cc4dfSMiklos Szeredi .show_options = hostfs_show_options,
2671da177e4SLinus Torvalds };
2681da177e4SLinus Torvalds
hostfs_readdir(struct file * file,struct dir_context * ctx)2699e443bc3SJames Hogan static int hostfs_readdir(struct file *file, struct dir_context *ctx)
2701da177e4SLinus Torvalds {
2711da177e4SLinus Torvalds void *dir;
2721da177e4SLinus Torvalds char *name;
2731da177e4SLinus Torvalds unsigned long long next, ino;
2741da177e4SLinus Torvalds int error, len;
2753ee6bd8eSGeert Uytterhoeven unsigned int type;
2761da177e4SLinus Torvalds
277c5322220SAl Viro name = dentry_name(file->f_path.dentry);
278f1adc05eSJeff Dike if (name == NULL)
279f1adc05eSJeff Dike return -ENOMEM;
2801da177e4SLinus Torvalds dir = open_dir(name, &error);
281e9193059SAl Viro __putname(name);
282f1adc05eSJeff Dike if (dir == NULL)
283f1adc05eSJeff Dike return -error;
2848e28bc7eSAl Viro next = ctx->pos;
2850c9bd636SRichard Weinberger seek_dir(dir, next);
2863ee6bd8eSGeert Uytterhoeven while ((name = read_dir(dir, &next, &ino, &len, &type)) != NULL) {
2878e28bc7eSAl Viro if (!dir_emit(ctx, name, len, ino, type))
2888e28bc7eSAl Viro break;
2898e28bc7eSAl Viro ctx->pos = next;
2901da177e4SLinus Torvalds }
2911da177e4SLinus Torvalds close_dir(dir);
292f1adc05eSJeff Dike return 0;
2931da177e4SLinus Torvalds }
2941da177e4SLinus Torvalds
hostfs_open(struct inode * ino,struct file * file)2954c6dcafcSRichard Weinberger static int hostfs_open(struct inode *ino, struct file *file)
2961da177e4SLinus Torvalds {
2971da177e4SLinus Torvalds char *name;
298bd1052a2SRichard Weinberger fmode_t mode;
299f8ad850fSAl Viro int err;
300bd1052a2SRichard Weinberger int r, w, fd;
3011da177e4SLinus Torvalds
3021da177e4SLinus Torvalds mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
3031da177e4SLinus Torvalds if ((mode & HOSTFS_I(ino)->mode) == mode)
304f1adc05eSJeff Dike return 0;
3051da177e4SLinus Torvalds
306f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode;
3071da177e4SLinus Torvalds
308f8ad850fSAl Viro retry:
309a9d1958bSRichard Weinberger r = w = 0;
310a9d1958bSRichard Weinberger
311f8ad850fSAl Viro if (mode & FMODE_READ)
3121da177e4SLinus Torvalds r = 1;
313f8ad850fSAl Viro if (mode & FMODE_WRITE)
314112a5da7SRichard Weinberger r = w = 1;
3151da177e4SLinus Torvalds
316d692d397SAl Viro name = dentry_name(file_dentry(file));
3171da177e4SLinus Torvalds if (name == NULL)
318f1adc05eSJeff Dike return -ENOMEM;
3191da177e4SLinus Torvalds
3201da177e4SLinus Torvalds fd = open_file(name, r, w, append);
321e9193059SAl Viro __putname(name);
322f1adc05eSJeff Dike if (fd < 0)
323f1adc05eSJeff Dike return fd;
324f8ad850fSAl Viro
32569886e67SRichard Weinberger mutex_lock(&HOSTFS_I(ino)->open_mutex);
326f8ad850fSAl Viro /* somebody else had handled it first? */
327f8ad850fSAl Viro if ((mode & HOSTFS_I(ino)->mode) == mode) {
32869886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex);
329af955658SRichard Weinberger close_file(&fd);
330f8ad850fSAl Viro return 0;
331f8ad850fSAl Viro }
332f8ad850fSAl Viro if ((mode | HOSTFS_I(ino)->mode) != mode) {
333f8ad850fSAl Viro mode |= HOSTFS_I(ino)->mode;
33469886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex);
335f8ad850fSAl Viro close_file(&fd);
336f8ad850fSAl Viro goto retry;
337f8ad850fSAl Viro }
338f8ad850fSAl Viro if (HOSTFS_I(ino)->fd == -1) {
339f8ad850fSAl Viro HOSTFS_I(ino)->fd = fd;
340f8ad850fSAl Viro } else {
341f8ad850fSAl Viro err = replace_file(fd, HOSTFS_I(ino)->fd);
342f8ad850fSAl Viro close_file(&fd);
343f8ad850fSAl Viro if (err < 0) {
34469886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex);
345f8ad850fSAl Viro return err;
346f8ad850fSAl Viro }
347f8ad850fSAl Viro }
348f8ad850fSAl Viro HOSTFS_I(ino)->mode = mode;
34969886e67SRichard Weinberger mutex_unlock(&HOSTFS_I(ino)->open_mutex);
3501da177e4SLinus Torvalds
351f1adc05eSJeff Dike return 0;
3521da177e4SLinus Torvalds }
3531da177e4SLinus Torvalds
hostfs_file_release(struct inode * inode,struct file * file)35465984ff9SRichard Weinberger static int hostfs_file_release(struct inode *inode, struct file *file)
35565984ff9SRichard Weinberger {
35665984ff9SRichard Weinberger filemap_write_and_wait(inode->i_mapping);
35765984ff9SRichard Weinberger
35865984ff9SRichard Weinberger return 0;
35965984ff9SRichard Weinberger }
36065984ff9SRichard Weinberger
hostfs_fsync(struct file * file,loff_t start,loff_t end,int datasync)3619e443bc3SJames Hogan static int hostfs_fsync(struct file *file, loff_t start, loff_t end,
3629e443bc3SJames Hogan int datasync)
3631da177e4SLinus Torvalds {
36402c24a82SJosef Bacik struct inode *inode = file->f_mapping->host;
36502c24a82SJosef Bacik int ret;
36602c24a82SJosef Bacik
3673b49c9a1SJeff Layton ret = file_write_and_wait_range(file, start, end);
36802c24a82SJosef Bacik if (ret)
36902c24a82SJosef Bacik return ret;
37002c24a82SJosef Bacik
3715955102cSAl Viro inode_lock(inode);
37202c24a82SJosef Bacik ret = fsync_file(HOSTFS_I(inode)->fd, datasync);
3735955102cSAl Viro inode_unlock(inode);
37402c24a82SJosef Bacik
37502c24a82SJosef Bacik return ret;
3761da177e4SLinus Torvalds }
3771da177e4SLinus Torvalds
3784b6f5d20SArjan van de Ven static const struct file_operations hostfs_file_fops = {
3791da177e4SLinus Torvalds .llseek = generic_file_llseek,
3802cb1e089SDavid Howells .splice_read = filemap_splice_read,
3811568cb0eSJohannes Berg .splice_write = iter_file_splice_write,
382aad4f8bbSAl Viro .read_iter = generic_file_read_iter,
3838174202bSAl Viro .write_iter = generic_file_write_iter,
3841da177e4SLinus Torvalds .mmap = generic_file_mmap,
3854c6dcafcSRichard Weinberger .open = hostfs_open,
38665984ff9SRichard Weinberger .release = hostfs_file_release,
3871da177e4SLinus Torvalds .fsync = hostfs_fsync,
3881da177e4SLinus Torvalds };
3891da177e4SLinus Torvalds
3904b6f5d20SArjan van de Ven static const struct file_operations hostfs_dir_fops = {
3911da177e4SLinus Torvalds .llseek = generic_file_llseek,
392552a9d48SAl Viro .iterate_shared = hostfs_readdir,
3931da177e4SLinus Torvalds .read = generic_read_dir,
3944c6dcafcSRichard Weinberger .open = hostfs_open,
3954c6dcafcSRichard Weinberger .fsync = hostfs_fsync,
3961da177e4SLinus Torvalds };
3971da177e4SLinus Torvalds
hostfs_writepage(struct page * page,struct writeback_control * wbc)3989e443bc3SJames Hogan static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
3991da177e4SLinus Torvalds {
4001da177e4SLinus Torvalds struct address_space *mapping = page->mapping;
4011da177e4SLinus Torvalds struct inode *inode = mapping->host;
4021da177e4SLinus Torvalds char *buffer;
403af6aa1b9SRichard Weinberger loff_t base = page_offset(page);
40409cbfeafSKirill A. Shutemov int count = PAGE_SIZE;
40509cbfeafSKirill A. Shutemov int end_index = inode->i_size >> PAGE_SHIFT;
4061da177e4SLinus Torvalds int err;
4071da177e4SLinus Torvalds
4081da177e4SLinus Torvalds if (page->index >= end_index)
40909cbfeafSKirill A. Shutemov count = inode->i_size & (PAGE_SIZE-1);
4101da177e4SLinus Torvalds
411e0820368SFabio M. De Francesco buffer = kmap_local_page(page);
4121da177e4SLinus Torvalds
4131da177e4SLinus Torvalds err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
4141da177e4SLinus Torvalds if (err != count) {
415e775dfb3SMatthew Wilcox (Oracle) if (err >= 0)
416e775dfb3SMatthew Wilcox (Oracle) err = -EIO;
417e775dfb3SMatthew Wilcox (Oracle) mapping_set_error(mapping, err);
4181da177e4SLinus Torvalds goto out;
4191da177e4SLinus Torvalds }
4201da177e4SLinus Torvalds
4211da177e4SLinus Torvalds if (base > inode->i_size)
4221da177e4SLinus Torvalds inode->i_size = base;
4231da177e4SLinus Torvalds
4241da177e4SLinus Torvalds err = 0;
4251da177e4SLinus Torvalds
4261da177e4SLinus Torvalds out:
427e0820368SFabio M. De Francesco kunmap_local(buffer);
4281da177e4SLinus Torvalds unlock_page(page);
429e0820368SFabio M. De Francesco
4301da177e4SLinus Torvalds return err;
4311da177e4SLinus Torvalds }
4321da177e4SLinus Torvalds
hostfs_read_folio(struct file * file,struct folio * folio)4338f4fe249SMatthew Wilcox (Oracle) static int hostfs_read_folio(struct file *file, struct folio *folio)
4341da177e4SLinus Torvalds {
4358f4fe249SMatthew Wilcox (Oracle) struct page *page = &folio->page;
4361da177e4SLinus Torvalds char *buffer;
437af6aa1b9SRichard Weinberger loff_t start = page_offset(page);
438b86b413aSRichard Weinberger int bytes_read, ret = 0;
4391da177e4SLinus Torvalds
440e0820368SFabio M. De Francesco buffer = kmap_local_page(page);
44141761ddfSRichard Weinberger bytes_read = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
44209cbfeafSKirill A. Shutemov PAGE_SIZE);
44341761ddfSRichard Weinberger if (bytes_read < 0) {
444b86b413aSRichard Weinberger ClearPageUptodate(page);
445b86b413aSRichard Weinberger SetPageError(page);
44641761ddfSRichard Weinberger ret = bytes_read;
44784b3db04SJeff Dike goto out;
44841761ddfSRichard Weinberger }
4491da177e4SLinus Torvalds
45009cbfeafSKirill A. Shutemov memset(buffer + bytes_read, 0, PAGE_SIZE - bytes_read);
4511da177e4SLinus Torvalds
452b86b413aSRichard Weinberger ClearPageError(page);
4531da177e4SLinus Torvalds SetPageUptodate(page);
454b86b413aSRichard Weinberger
4551da177e4SLinus Torvalds out:
456b86b413aSRichard Weinberger flush_dcache_page(page);
457e0820368SFabio M. De Francesco kunmap_local(buffer);
4581da177e4SLinus Torvalds unlock_page(page);
459e0820368SFabio M. De Francesco
46041761ddfSRichard Weinberger return ret;
4611da177e4SLinus Torvalds }
4621da177e4SLinus Torvalds
hostfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)4639e443bc3SJames Hogan static int hostfs_write_begin(struct file *file, struct address_space *mapping,
4649d6b0cd7SMatthew Wilcox (Oracle) loff_t pos, unsigned len,
465ae361ff4SNick Piggin struct page **pagep, void **fsdata)
4661da177e4SLinus Torvalds {
46709cbfeafSKirill A. Shutemov pgoff_t index = pos >> PAGE_SHIFT;
468ae361ff4SNick Piggin
469b7446e7cSMatthew Wilcox (Oracle) *pagep = grab_cache_page_write_begin(mapping, index);
470ae361ff4SNick Piggin if (!*pagep)
471ae361ff4SNick Piggin return -ENOMEM;
472ae361ff4SNick Piggin return 0;
473ae361ff4SNick Piggin }
474ae361ff4SNick Piggin
hostfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)4759e443bc3SJames Hogan static int hostfs_write_end(struct file *file, struct address_space *mapping,
476ae361ff4SNick Piggin loff_t pos, unsigned len, unsigned copied,
477ae361ff4SNick Piggin struct page *page, void *fsdata)
478ae361ff4SNick Piggin {
479ae361ff4SNick Piggin struct inode *inode = mapping->host;
480ae361ff4SNick Piggin void *buffer;
48109cbfeafSKirill A. Shutemov unsigned from = pos & (PAGE_SIZE - 1);
4821da177e4SLinus Torvalds int err;
4831da177e4SLinus Torvalds
484e0820368SFabio M. De Francesco buffer = kmap_local_page(page);
485ae361ff4SNick Piggin err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
486e0820368SFabio M. De Francesco kunmap_local(buffer);
4871da177e4SLinus Torvalds
48809cbfeafSKirill A. Shutemov if (!PageUptodate(page) && err == PAGE_SIZE)
489ae361ff4SNick Piggin SetPageUptodate(page);
4901da177e4SLinus Torvalds
49184b3db04SJeff Dike /*
49284b3db04SJeff Dike * If err > 0, write_file has added err to pos, so we are comparing
493ae361ff4SNick Piggin * i_size against the last byte written.
494ae361ff4SNick Piggin */
495ae361ff4SNick Piggin if (err > 0 && (pos > inode->i_size))
496ae361ff4SNick Piggin inode->i_size = pos;
497ae361ff4SNick Piggin unlock_page(page);
49809cbfeafSKirill A. Shutemov put_page(page);
49930f04a4eSPaolo 'Blaisorblade' Giarrusso
500f1adc05eSJeff Dike return err;
5011da177e4SLinus Torvalds }
5021da177e4SLinus Torvalds
503f5e54d6eSChristoph Hellwig static const struct address_space_operations hostfs_aops = {
5041da177e4SLinus Torvalds .writepage = hostfs_writepage,
5058f4fe249SMatthew Wilcox (Oracle) .read_folio = hostfs_read_folio,
506187c82cbSMatthew Wilcox (Oracle) .dirty_folio = filemap_dirty_folio,
507ae361ff4SNick Piggin .write_begin = hostfs_write_begin,
508ae361ff4SNick Piggin .write_end = hostfs_write_end,
5091da177e4SLinus Torvalds };
5101da177e4SLinus Torvalds
hostfs_inode_update(struct inode * ino,const struct hostfs_stat * st)51174ce793bSMickaël Salaün static int hostfs_inode_update(struct inode *ino, const struct hostfs_stat *st)
5121da177e4SLinus Torvalds {
51374ce793bSMickaël Salaün set_nlink(ino, st->nlink);
51474ce793bSMickaël Salaün i_uid_write(ino, st->uid);
51574ce793bSMickaël Salaün i_gid_write(ino, st->gid);
51674ce793bSMickaël Salaün ino->i_atime =
51774ce793bSMickaël Salaün (struct timespec64){ st->atime.tv_sec, st->atime.tv_nsec };
51874ce793bSMickaël Salaün ino->i_mtime =
51974ce793bSMickaël Salaün (struct timespec64){ st->mtime.tv_sec, st->mtime.tv_nsec };
520*66e79d89SJeff Layton inode_set_ctime(ino, st->ctime.tv_sec, st->ctime.tv_nsec);
52174ce793bSMickaël Salaün ino->i_size = st->size;
52274ce793bSMickaël Salaün ino->i_blocks = st->blocks;
52374ce793bSMickaël Salaün return 0;
52474ce793bSMickaël Salaün }
52574ce793bSMickaël Salaün
hostfs_inode_set(struct inode * ino,void * data)52674ce793bSMickaël Salaün static int hostfs_inode_set(struct inode *ino, void *data)
52774ce793bSMickaël Salaün {
52874ce793bSMickaël Salaün struct hostfs_stat *st = data;
5294754b825SAl Viro dev_t rdev;
5301da177e4SLinus Torvalds
5311da177e4SLinus Torvalds /* Reencode maj and min with the kernel encoding.*/
53274ce793bSMickaël Salaün rdev = MKDEV(st->maj, st->min);
5331da177e4SLinus Torvalds
53474ce793bSMickaël Salaün switch (st->mode & S_IFMT) {
5354754b825SAl Viro case S_IFLNK:
536d0352d3eSAl Viro ino->i_op = &hostfs_link_iops;
5374754b825SAl Viro break;
5384754b825SAl Viro case S_IFDIR:
5394754b825SAl Viro ino->i_op = &hostfs_dir_iops;
5404754b825SAl Viro ino->i_fop = &hostfs_dir_fops;
5414754b825SAl Viro break;
5424754b825SAl Viro case S_IFCHR:
5434754b825SAl Viro case S_IFBLK:
5444754b825SAl Viro case S_IFIFO:
5454754b825SAl Viro case S_IFSOCK:
54674ce793bSMickaël Salaün init_special_inode(ino, st->mode & S_IFMT, rdev);
5474754b825SAl Viro ino->i_op = &hostfs_iops;
5484754b825SAl Viro break;
5492ad2dca6SRichard Weinberger case S_IFREG:
5504754b825SAl Viro ino->i_op = &hostfs_iops;
5514754b825SAl Viro ino->i_fop = &hostfs_file_fops;
5524754b825SAl Viro ino->i_mapping->a_ops = &hostfs_aops;
5532ad2dca6SRichard Weinberger break;
5542ad2dca6SRichard Weinberger default:
5552ad2dca6SRichard Weinberger return -EIO;
5561da177e4SLinus Torvalds }
5574754b825SAl Viro
55874ce793bSMickaël Salaün HOSTFS_I(ino)->dev = st->dev;
55974ce793bSMickaël Salaün ino->i_ino = st->ino;
56074ce793bSMickaël Salaün ino->i_mode = st->mode;
56174ce793bSMickaël Salaün return hostfs_inode_update(ino, st);
56274ce793bSMickaël Salaün }
56374ce793bSMickaël Salaün
hostfs_inode_test(struct inode * inode,void * data)56474ce793bSMickaël Salaün static int hostfs_inode_test(struct inode *inode, void *data)
56574ce793bSMickaël Salaün {
56674ce793bSMickaël Salaün const struct hostfs_stat *st = data;
56774ce793bSMickaël Salaün
56874ce793bSMickaël Salaün return inode->i_ino == st->ino && HOSTFS_I(inode)->dev == st->dev;
56974ce793bSMickaël Salaün }
57074ce793bSMickaël Salaün
hostfs_iget(struct super_block * sb,char * name)57174ce793bSMickaël Salaün static struct inode *hostfs_iget(struct super_block *sb, char *name)
57274ce793bSMickaël Salaün {
57374ce793bSMickaël Salaün struct inode *inode;
57474ce793bSMickaël Salaün struct hostfs_stat st;
57574ce793bSMickaël Salaün int err = stat_file(name, &st, -1);
57674ce793bSMickaël Salaün
57774ce793bSMickaël Salaün if (err)
57874ce793bSMickaël Salaün return ERR_PTR(err);
57974ce793bSMickaël Salaün
58074ce793bSMickaël Salaün inode = iget5_locked(sb, st.ino, hostfs_inode_test, hostfs_inode_set,
58174ce793bSMickaël Salaün &st);
58274ce793bSMickaël Salaün if (!inode)
58374ce793bSMickaël Salaün return ERR_PTR(-ENOMEM);
58474ce793bSMickaël Salaün
58574ce793bSMickaël Salaün if (inode->i_state & I_NEW) {
58674ce793bSMickaël Salaün unlock_new_inode(inode);
58774ce793bSMickaël Salaün } else {
58874ce793bSMickaël Salaün spin_lock(&inode->i_lock);
58974ce793bSMickaël Salaün hostfs_inode_update(inode, &st);
59074ce793bSMickaël Salaün spin_unlock(&inode->i_lock);
59174ce793bSMickaël Salaün }
59274ce793bSMickaël Salaün
59374ce793bSMickaël Salaün return inode;
5941da177e4SLinus Torvalds }
5951da177e4SLinus Torvalds
hostfs_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)5966c960e68SChristian Brauner static int hostfs_create(struct mnt_idmap *idmap, struct inode *dir,
597549c7297SChristian Brauner struct dentry *dentry, umode_t mode, bool excl)
5981da177e4SLinus Torvalds {
5991da177e4SLinus Torvalds struct inode *inode;
6001da177e4SLinus Torvalds char *name;
60174ce793bSMickaël Salaün int fd;
6021da177e4SLinus Torvalds
603c5322220SAl Viro name = dentry_name(dentry);
6041da177e4SLinus Torvalds if (name == NULL)
60574ce793bSMickaël Salaün return -ENOMEM;
6061da177e4SLinus Torvalds
607a718c922SRichard Weinberger fd = file_create(name, mode & 0777);
60874ce793bSMickaël Salaün if (fd < 0) {
609e9193059SAl Viro __putname(name);
61074ce793bSMickaël Salaün return fd;
61174ce793bSMickaël Salaün }
61274ce793bSMickaël Salaün
61374ce793bSMickaël Salaün inode = hostfs_iget(dir->i_sb, name);
61474ce793bSMickaël Salaün __putname(name);
61574ce793bSMickaël Salaün if (IS_ERR(inode))
61674ce793bSMickaël Salaün return PTR_ERR(inode);
6171da177e4SLinus Torvalds
6181da177e4SLinus Torvalds HOSTFS_I(inode)->fd = fd;
6191da177e4SLinus Torvalds HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
6201da177e4SLinus Torvalds d_instantiate(dentry, inode);
621f1adc05eSJeff Dike return 0;
6221da177e4SLinus Torvalds }
6231da177e4SLinus Torvalds
hostfs_lookup(struct inode * ino,struct dentry * dentry,unsigned int flags)6249e443bc3SJames Hogan static struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
62500cd8dd3SAl Viro unsigned int flags)
6261da177e4SLinus Torvalds {
62774ce793bSMickaël Salaün struct inode *inode = NULL;
6281da177e4SLinus Torvalds char *name;
6291da177e4SLinus Torvalds
630c5322220SAl Viro name = dentry_name(dentry);
63174ce793bSMickaël Salaün if (name == NULL)
63274ce793bSMickaël Salaün return ERR_PTR(-ENOMEM);
63374ce793bSMickaël Salaün
63474ce793bSMickaël Salaün inode = hostfs_iget(ino->i_sb, name);
635e9193059SAl Viro __putname(name);
63674ce793bSMickaël Salaün if (IS_ERR(inode)) {
63774ce793bSMickaël Salaün if (PTR_ERR(inode) == -ENOENT)
63874ce793bSMickaël Salaün inode = NULL;
63974ce793bSMickaël Salaün else
64074ce793bSMickaël Salaün return ERR_CAST(inode);
6411da177e4SLinus Torvalds }
64274ce793bSMickaël Salaün
64350f30740SAl Viro return d_splice_alias(inode, dentry);
6441da177e4SLinus Torvalds }
6451da177e4SLinus Torvalds
hostfs_link(struct dentry * to,struct inode * ino,struct dentry * from)6469e443bc3SJames Hogan static int hostfs_link(struct dentry *to, struct inode *ino,
6479e443bc3SJames Hogan struct dentry *from)
6481da177e4SLinus Torvalds {
6491da177e4SLinus Torvalds char *from_name, *to_name;
6501da177e4SLinus Torvalds int err;
6511da177e4SLinus Torvalds
652c5322220SAl Viro if ((from_name = dentry_name(from)) == NULL)
653f1adc05eSJeff Dike return -ENOMEM;
654c5322220SAl Viro to_name = dentry_name(to);
6551da177e4SLinus Torvalds if (to_name == NULL) {
656e9193059SAl Viro __putname(from_name);
657f1adc05eSJeff Dike return -ENOMEM;
6581da177e4SLinus Torvalds }
6591da177e4SLinus Torvalds err = link_file(to_name, from_name);
660e9193059SAl Viro __putname(from_name);
661e9193059SAl Viro __putname(to_name);
662f1adc05eSJeff Dike return err;
6631da177e4SLinus Torvalds }
6641da177e4SLinus Torvalds
hostfs_unlink(struct inode * ino,struct dentry * dentry)6659e443bc3SJames Hogan static int hostfs_unlink(struct inode *ino, struct dentry *dentry)
6661da177e4SLinus Torvalds {
6671da177e4SLinus Torvalds char *file;
6681da177e4SLinus Torvalds int err;
6691da177e4SLinus Torvalds
6701da177e4SLinus Torvalds if (append)
671f1adc05eSJeff Dike return -EPERM;
6721da177e4SLinus Torvalds
673f8d7e187SAl Viro if ((file = dentry_name(dentry)) == NULL)
674f8d7e187SAl Viro return -ENOMEM;
675f8d7e187SAl Viro
6761da177e4SLinus Torvalds err = unlink_file(file);
677e9193059SAl Viro __putname(file);
678f1adc05eSJeff Dike return err;
6791da177e4SLinus Torvalds }
6801da177e4SLinus Torvalds
hostfs_symlink(struct mnt_idmap * idmap,struct inode * ino,struct dentry * dentry,const char * to)6817a77db95SChristian Brauner static int hostfs_symlink(struct mnt_idmap *idmap, struct inode *ino,
682549c7297SChristian Brauner struct dentry *dentry, const char *to)
6831da177e4SLinus Torvalds {
6841da177e4SLinus Torvalds char *file;
6851da177e4SLinus Torvalds int err;
6861da177e4SLinus Torvalds
687c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL)
688f1adc05eSJeff Dike return -ENOMEM;
6891da177e4SLinus Torvalds err = make_symlink(file, to);
690e9193059SAl Viro __putname(file);
691f1adc05eSJeff Dike return err;
6921da177e4SLinus Torvalds }
6931da177e4SLinus Torvalds
hostfs_mkdir(struct mnt_idmap * idmap,struct inode * ino,struct dentry * dentry,umode_t mode)694c54bd91eSChristian Brauner static int hostfs_mkdir(struct mnt_idmap *idmap, struct inode *ino,
695549c7297SChristian Brauner struct dentry *dentry, umode_t mode)
6961da177e4SLinus Torvalds {
6971da177e4SLinus Torvalds char *file;
6981da177e4SLinus Torvalds int err;
6991da177e4SLinus Torvalds
700c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL)
701f1adc05eSJeff Dike return -ENOMEM;
7021da177e4SLinus Torvalds err = do_mkdir(file, mode);
703e9193059SAl Viro __putname(file);
704f1adc05eSJeff Dike return err;
7051da177e4SLinus Torvalds }
7061da177e4SLinus Torvalds
hostfs_rmdir(struct inode * ino,struct dentry * dentry)7079e443bc3SJames Hogan static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
7081da177e4SLinus Torvalds {
7091da177e4SLinus Torvalds char *file;
7101da177e4SLinus Torvalds int err;
7111da177e4SLinus Torvalds
712c5322220SAl Viro if ((file = dentry_name(dentry)) == NULL)
713f1adc05eSJeff Dike return -ENOMEM;
7146380161cSDominik Brodowski err = hostfs_do_rmdir(file);
715e9193059SAl Viro __putname(file);
716f1adc05eSJeff Dike return err;
7171da177e4SLinus Torvalds }
7181da177e4SLinus Torvalds
hostfs_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)7195ebb29beSChristian Brauner static int hostfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
720549c7297SChristian Brauner struct dentry *dentry, umode_t mode, dev_t dev)
7211da177e4SLinus Torvalds {
7221da177e4SLinus Torvalds struct inode *inode;
7231da177e4SLinus Torvalds char *name;
7240a370e5dSDavid Howells int err;
7251da177e4SLinus Torvalds
726c5322220SAl Viro name = dentry_name(dentry);
7271da177e4SLinus Torvalds if (name == NULL)
72874ce793bSMickaël Salaün return -ENOMEM;
7291da177e4SLinus Torvalds
73088f6cd0cSJohannes Stezenbach err = do_mknod(name, mode, MAJOR(dev), MINOR(dev));
73174ce793bSMickaël Salaün if (err) {
732e9193059SAl Viro __putname(name);
73374ce793bSMickaël Salaün return err;
73474ce793bSMickaël Salaün }
73574ce793bSMickaël Salaün
73674ce793bSMickaël Salaün inode = hostfs_iget(dir->i_sb, name);
73774ce793bSMickaël Salaün __putname(name);
73874ce793bSMickaël Salaün if (IS_ERR(inode))
73974ce793bSMickaël Salaün return PTR_ERR(inode);
7401da177e4SLinus Torvalds
7411da177e4SLinus Torvalds d_instantiate(dentry, inode);
742f1adc05eSJeff Dike return 0;
7431da177e4SLinus Torvalds }
7441da177e4SLinus Torvalds
hostfs_rename2(struct mnt_idmap * idmap,struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)745e18275aeSChristian Brauner static int hostfs_rename2(struct mnt_idmap *idmap,
746549c7297SChristian Brauner struct inode *old_dir, struct dentry *old_dentry,
7479a423bb6SMiklos Szeredi struct inode *new_dir, struct dentry *new_dentry,
7489a423bb6SMiklos Szeredi unsigned int flags)
7491da177e4SLinus Torvalds {
7509a423bb6SMiklos Szeredi char *old_name, *new_name;
7511da177e4SLinus Torvalds int err;
7521da177e4SLinus Torvalds
7539a423bb6SMiklos Szeredi if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
7549a423bb6SMiklos Szeredi return -EINVAL;
7559a423bb6SMiklos Szeredi
7569a423bb6SMiklos Szeredi old_name = dentry_name(old_dentry);
7579a423bb6SMiklos Szeredi if (old_name == NULL)
758f1adc05eSJeff Dike return -ENOMEM;
7599a423bb6SMiklos Szeredi new_name = dentry_name(new_dentry);
7609a423bb6SMiklos Szeredi if (new_name == NULL) {
7619a423bb6SMiklos Szeredi __putname(old_name);
762f1adc05eSJeff Dike return -ENOMEM;
7631da177e4SLinus Torvalds }
7649a423bb6SMiklos Szeredi if (!flags)
7659a423bb6SMiklos Szeredi err = rename_file(old_name, new_name);
7669a423bb6SMiklos Szeredi else
7679a423bb6SMiklos Szeredi err = rename2_file(old_name, new_name, flags);
7689a423bb6SMiklos Szeredi
7699a423bb6SMiklos Szeredi __putname(old_name);
7709a423bb6SMiklos Szeredi __putname(new_name);
771f1adc05eSJeff Dike return err;
7721da177e4SLinus Torvalds }
7731da177e4SLinus Torvalds
hostfs_permission(struct mnt_idmap * idmap,struct inode * ino,int desired)7744609e1f1SChristian Brauner static int hostfs_permission(struct mnt_idmap *idmap,
775549c7297SChristian Brauner struct inode *ino, int desired)
7761da177e4SLinus Torvalds {
7771da177e4SLinus Torvalds char *name;
7781da177e4SLinus Torvalds int r = 0, w = 0, x = 0, err;
7791da177e4SLinus Torvalds
78010556cb2SAl Viro if (desired & MAY_NOT_BLOCK)
781b74c79e9SNick Piggin return -ECHILD;
782b74c79e9SNick Piggin
7831da177e4SLinus Torvalds if (desired & MAY_READ) r = 1;
7841da177e4SLinus Torvalds if (desired & MAY_WRITE) w = 1;
7851da177e4SLinus Torvalds if (desired & MAY_EXEC) x = 1;
786c5322220SAl Viro name = inode_name(ino);
787f1adc05eSJeff Dike if (name == NULL)
788f1adc05eSJeff Dike return -ENOMEM;
7891da177e4SLinus Torvalds
7901da177e4SLinus Torvalds if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
7911da177e4SLinus Torvalds S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
7921da177e4SLinus Torvalds err = 0;
7931da177e4SLinus Torvalds else
7941da177e4SLinus Torvalds err = access_file(name, r, w, x);
795e9193059SAl Viro __putname(name);
7961da177e4SLinus Torvalds if (!err)
7974609e1f1SChristian Brauner err = generic_permission(&nop_mnt_idmap, ino, desired);
7981da177e4SLinus Torvalds return err;
7991da177e4SLinus Torvalds }
8001da177e4SLinus Torvalds
hostfs_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * attr)801c1632a0fSChristian Brauner static int hostfs_setattr(struct mnt_idmap *idmap,
802549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr)
8031da177e4SLinus Torvalds {
8042b0143b5SDavid Howells struct inode *inode = d_inode(dentry);
8051da177e4SLinus Torvalds struct hostfs_iattr attrs;
8061da177e4SLinus Torvalds char *name;
8071da177e4SLinus Torvalds int err;
8081da177e4SLinus Torvalds
8091025774cSChristoph Hellwig int fd = HOSTFS_I(inode)->fd;
8105822b7faSAlberto Bertogli
811c1632a0fSChristian Brauner err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
8121da177e4SLinus Torvalds if (err)
8131da177e4SLinus Torvalds return err;
8141da177e4SLinus Torvalds
8151da177e4SLinus Torvalds if (append)
8161da177e4SLinus Torvalds attr->ia_valid &= ~ATTR_SIZE;
8171da177e4SLinus Torvalds
8181da177e4SLinus Torvalds attrs.ia_valid = 0;
8191da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MODE) {
8201da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MODE;
8211da177e4SLinus Torvalds attrs.ia_mode = attr->ia_mode;
8221da177e4SLinus Torvalds }
8231da177e4SLinus Torvalds if (attr->ia_valid & ATTR_UID) {
8241da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_UID;
82529f82ae5SEric W. Biederman attrs.ia_uid = from_kuid(&init_user_ns, attr->ia_uid);
8261da177e4SLinus Torvalds }
8271da177e4SLinus Torvalds if (attr->ia_valid & ATTR_GID) {
8281da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_GID;
82929f82ae5SEric W. Biederman attrs.ia_gid = from_kgid(&init_user_ns, attr->ia_gid);
8301da177e4SLinus Torvalds }
8311da177e4SLinus Torvalds if (attr->ia_valid & ATTR_SIZE) {
8321da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_SIZE;
8331da177e4SLinus Torvalds attrs.ia_size = attr->ia_size;
8341da177e4SLinus Torvalds }
8351da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME) {
8361da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME;
837bca30265SArnd Bergmann attrs.ia_atime = (struct hostfs_timespec)
838bca30265SArnd Bergmann { attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec };
8391da177e4SLinus Torvalds }
8401da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME) {
8411da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME;
842bca30265SArnd Bergmann attrs.ia_mtime = (struct hostfs_timespec)
843bca30265SArnd Bergmann { attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec };
8441da177e4SLinus Torvalds }
8451da177e4SLinus Torvalds if (attr->ia_valid & ATTR_CTIME) {
8461da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_CTIME;
847bca30265SArnd Bergmann attrs.ia_ctime = (struct hostfs_timespec)
848bca30265SArnd Bergmann { attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec };
8491da177e4SLinus Torvalds }
8501da177e4SLinus Torvalds if (attr->ia_valid & ATTR_ATIME_SET) {
8511da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
8521da177e4SLinus Torvalds }
8531da177e4SLinus Torvalds if (attr->ia_valid & ATTR_MTIME_SET) {
8541da177e4SLinus Torvalds attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
8551da177e4SLinus Torvalds }
856c5322220SAl Viro name = dentry_name(dentry);
857f1adc05eSJeff Dike if (name == NULL)
858f1adc05eSJeff Dike return -ENOMEM;
8595822b7faSAlberto Bertogli err = set_attr(name, &attrs, fd);
860e9193059SAl Viro __putname(name);
8611da177e4SLinus Torvalds if (err)
862f1adc05eSJeff Dike return err;
8631da177e4SLinus Torvalds
8641025774cSChristoph Hellwig if ((attr->ia_valid & ATTR_SIZE) &&
865bc077320SMarco Stornelli attr->ia_size != i_size_read(inode))
8663be2be0aSMarco Stornelli truncate_setsize(inode, attr->ia_size);
8671025774cSChristoph Hellwig
868c1632a0fSChristian Brauner setattr_copy(&nop_mnt_idmap, inode, attr);
8691025774cSChristoph Hellwig mark_inode_dirty(inode);
8701025774cSChristoph Hellwig return 0;
8711da177e4SLinus Torvalds }
8721da177e4SLinus Torvalds
87392e1d5beSArjan van de Ven static const struct inode_operations hostfs_iops = {
8741da177e4SLinus Torvalds .permission = hostfs_permission,
8751da177e4SLinus Torvalds .setattr = hostfs_setattr,
8761da177e4SLinus Torvalds };
8771da177e4SLinus Torvalds
87892e1d5beSArjan van de Ven static const struct inode_operations hostfs_dir_iops = {
8791da177e4SLinus Torvalds .create = hostfs_create,
8801da177e4SLinus Torvalds .lookup = hostfs_lookup,
8811da177e4SLinus Torvalds .link = hostfs_link,
8821da177e4SLinus Torvalds .unlink = hostfs_unlink,
8831da177e4SLinus Torvalds .symlink = hostfs_symlink,
8841da177e4SLinus Torvalds .mkdir = hostfs_mkdir,
8851da177e4SLinus Torvalds .rmdir = hostfs_rmdir,
8861da177e4SLinus Torvalds .mknod = hostfs_mknod,
8872773bf00SMiklos Szeredi .rename = hostfs_rename2,
8881da177e4SLinus Torvalds .permission = hostfs_permission,
8891da177e4SLinus Torvalds .setattr = hostfs_setattr,
8901da177e4SLinus Torvalds };
8911da177e4SLinus Torvalds
hostfs_get_link(struct dentry * dentry,struct inode * inode,struct delayed_call * done)8926b255391SAl Viro static const char *hostfs_get_link(struct dentry *dentry,
893fceef393SAl Viro struct inode *inode,
894fceef393SAl Viro struct delayed_call *done)
8951da177e4SLinus Torvalds {
8966b255391SAl Viro char *link;
8976b255391SAl Viro if (!dentry)
8986b255391SAl Viro return ERR_PTR(-ECHILD);
899fceef393SAl Viro link = kmalloc(PATH_MAX, GFP_KERNEL);
900d0352d3eSAl Viro if (link) {
901d0352d3eSAl Viro char *path = dentry_name(dentry);
902d0352d3eSAl Viro int err = -ENOMEM;
903d0352d3eSAl Viro if (path) {
9043b6036d1SAl Viro err = hostfs_do_readlink(path, link, PATH_MAX);
905d0352d3eSAl Viro if (err == PATH_MAX)
9061da177e4SLinus Torvalds err = -E2BIG;
907e9193059SAl Viro __putname(path);
9081da177e4SLinus Torvalds }
909d0352d3eSAl Viro if (err < 0) {
910fceef393SAl Viro kfree(link);
911680baacbSAl Viro return ERR_PTR(err);
912d0352d3eSAl Viro }
913d0352d3eSAl Viro } else {
914680baacbSAl Viro return ERR_PTR(-ENOMEM);
9151da177e4SLinus Torvalds }
9161da177e4SLinus Torvalds
917fceef393SAl Viro set_delayed_call(done, kfree_link, link);
918fceef393SAl Viro return link;
919d0352d3eSAl Viro }
920d0352d3eSAl Viro
921d0352d3eSAl Viro static const struct inode_operations hostfs_link_iops = {
9226b255391SAl Viro .get_link = hostfs_get_link,
9231da177e4SLinus Torvalds };
9241da177e4SLinus Torvalds
hostfs_fill_sb_common(struct super_block * sb,void * d,int silent)9251da177e4SLinus Torvalds static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
9261da177e4SLinus Torvalds {
9271da177e4SLinus Torvalds struct inode *root_inode;
92875e8defbSPaolo 'Blaisorblade' Giarrusso char *host_root_path, *req_root = d;
9291da177e4SLinus Torvalds int err;
9301da177e4SLinus Torvalds
9311da177e4SLinus Torvalds sb->s_blocksize = 1024;
9321da177e4SLinus Torvalds sb->s_blocksize_bits = 10;
9331da177e4SLinus Torvalds sb->s_magic = HOSTFS_SUPER_MAGIC;
9341da177e4SLinus Torvalds sb->s_op = &hostfs_sbops;
935b26d4cd3SAl Viro sb->s_d_op = &simple_dentry_operations;
936752fa51eSWolfgang Illmeyer sb->s_maxbytes = MAX_LFS_FILESIZE;
937ce72750fSSjoerd Simons err = super_setup_bdi(sb);
938ce72750fSSjoerd Simons if (err)
93974ce793bSMickaël Salaün return err;
9401da177e4SLinus Torvalds
941b58c4e96SAndy Shevchenko /* NULL is printed as '(null)' by printf(): avoid that. */
94275e8defbSPaolo 'Blaisorblade' Giarrusso if (req_root == NULL)
94375e8defbSPaolo 'Blaisorblade' Giarrusso req_root = "";
9441da177e4SLinus Torvalds
945601d2c38SAl Viro sb->s_fs_info = host_root_path =
946b58c4e96SAndy Shevchenko kasprintf(GFP_KERNEL, "%s/%s", root_ino, req_root);
94775e8defbSPaolo 'Blaisorblade' Giarrusso if (host_root_path == NULL)
94874ce793bSMickaël Salaün return -ENOMEM;
9491da177e4SLinus Torvalds
95074ce793bSMickaël Salaün root_inode = hostfs_iget(sb, host_root_path);
95174ce793bSMickaël Salaün if (IS_ERR(root_inode))
95274ce793bSMickaël Salaün return PTR_ERR(root_inode);
95352b209f7SAl Viro
9544754b825SAl Viro if (S_ISLNK(root_inode->i_mode)) {
95574ce793bSMickaël Salaün char *name;
95674ce793bSMickaël Salaün
95774ce793bSMickaël Salaün iput(root_inode);
95874ce793bSMickaël Salaün name = follow_link(host_root_path);
95974ce793bSMickaël Salaün if (IS_ERR(name))
96074ce793bSMickaël Salaün return PTR_ERR(name);
96174ce793bSMickaël Salaün
96274ce793bSMickaël Salaün root_inode = hostfs_iget(sb, name);
96352b209f7SAl Viro kfree(name);
96474ce793bSMickaël Salaün if (IS_ERR(root_inode))
96574ce793bSMickaël Salaün return PTR_ERR(root_inode);
9664754b825SAl Viro }
9671da177e4SLinus Torvalds
96848fde701SAl Viro sb->s_root = d_make_root(root_inode);
9691da177e4SLinus Torvalds if (sb->s_root == NULL)
97074ce793bSMickaël Salaün return -ENOMEM;
9711da177e4SLinus Torvalds
972f1adc05eSJeff Dike return 0;
9731da177e4SLinus Torvalds }
9741da177e4SLinus Torvalds
hostfs_read_sb(struct file_system_type * type,int flags,const char * dev_name,void * data)9753c26ff6eSAl Viro static struct dentry *hostfs_read_sb(struct file_system_type *type,
9761da177e4SLinus Torvalds int flags, const char *dev_name,
9773c26ff6eSAl Viro void *data)
9781da177e4SLinus Torvalds {
9793c26ff6eSAl Viro return mount_nodev(type, flags, data, hostfs_fill_sb_common);
9801da177e4SLinus Torvalds }
9811da177e4SLinus Torvalds
hostfs_kill_sb(struct super_block * s)982601d2c38SAl Viro static void hostfs_kill_sb(struct super_block *s)
983601d2c38SAl Viro {
984601d2c38SAl Viro kill_anon_super(s);
985601d2c38SAl Viro kfree(s->s_fs_info);
986601d2c38SAl Viro }
987601d2c38SAl Viro
9881da177e4SLinus Torvalds static struct file_system_type hostfs_type = {
9891da177e4SLinus Torvalds .owner = THIS_MODULE,
9901da177e4SLinus Torvalds .name = "hostfs",
9913c26ff6eSAl Viro .mount = hostfs_read_sb,
992601d2c38SAl Viro .kill_sb = hostfs_kill_sb,
9931da177e4SLinus Torvalds .fs_flags = 0,
9941da177e4SLinus Torvalds };
9953e64fe5bSEric W. Biederman MODULE_ALIAS_FS("hostfs");
9961da177e4SLinus Torvalds
init_hostfs(void)9971da177e4SLinus Torvalds static int __init init_hostfs(void)
9981da177e4SLinus Torvalds {
999a15f1e41SJohannes Berg hostfs_inode_cache = KMEM_CACHE(hostfs_inode_info, 0);
1000a15f1e41SJohannes Berg if (!hostfs_inode_cache)
1001a15f1e41SJohannes Berg return -ENOMEM;
1002f1adc05eSJeff Dike return register_filesystem(&hostfs_type);
10031da177e4SLinus Torvalds }
10041da177e4SLinus Torvalds
exit_hostfs(void)10051da177e4SLinus Torvalds static void __exit exit_hostfs(void)
10061da177e4SLinus Torvalds {
10071da177e4SLinus Torvalds unregister_filesystem(&hostfs_type);
1008a15f1e41SJohannes Berg kmem_cache_destroy(hostfs_inode_cache);
10091da177e4SLinus Torvalds }
10101da177e4SLinus Torvalds
10111da177e4SLinus Torvalds module_init(init_hostfs)
10121da177e4SLinus Torvalds module_exit(exit_hostfs)
10131da177e4SLinus Torvalds MODULE_LICENSE("GPL");
1014