2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
5 * Ported the filesystem routines to 2.5.
6 * 2003-02-10 Petr Baudis <pasky@ucw.cz>
10 #include <linux/module.h>
12 #include <linux/pagemap.h>
13 #include <linux/statfs.h>
18 struct hostfs_inode_info
{
22 struct inode vfs_inode
;
25 static inline struct hostfs_inode_info
*HOSTFS_I(struct inode
*inode
)
27 return list_entry(inode
, struct hostfs_inode_info
, vfs_inode
);
30 #define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_path.dentry->d_inode)
32 int hostfs_d_delete(struct dentry
*dentry
)
37 struct dentry_operations hostfs_dentry_ops
= {
38 .d_delete
= hostfs_d_delete
,
41 /* Changed in hostfs_args before the kernel starts running */
42 static char *root_ino
= "";
43 static int append
= 0;
45 #define HOSTFS_SUPER_MAGIC 0x00c0ffee
47 static const struct inode_operations hostfs_iops
;
48 static const struct inode_operations hostfs_dir_iops
;
49 static const struct address_space_operations hostfs_link_aops
;
52 static int __init
hostfs_args(char *options
, int *add
)
56 ptr
= strchr(options
, ',');
64 ptr
= strchr(options
, ',');
67 if (*options
!= '\0') {
68 if (!strcmp(options
, "append"))
70 else printf("hostfs_args - unsupported option - %s\n",
78 __uml_setup("hostfs=", hostfs_args
,
79 "hostfs=<root dir>,<flags>,...\n"
80 " This is used to set hostfs parameters. The root directory argument\n"
81 " is used to confine all hostfs mounts to within the specified directory\n"
82 " tree on the host. If this isn't specified, then a user inside UML can\n"
83 " mount anything on the host that's accessible to the user that's running\n"
85 " The only flag currently supported is 'append', which specifies that all\n"
86 " files opened by hostfs will be opened in append mode.\n\n"
90 static char *dentry_name(struct dentry
*dentry
, int extra
)
92 struct dentry
*parent
;
98 while (parent
->d_parent
!= parent
) {
99 len
+= parent
->d_name
.len
+ 1;
100 parent
= parent
->d_parent
;
103 root
= HOSTFS_I(parent
->d_inode
)->host_filename
;
105 name
= kmalloc(len
+ extra
+ 1, GFP_KERNEL
);
111 while (parent
->d_parent
!= parent
) {
112 len
-= parent
->d_name
.len
+ 1;
114 strncpy(&name
[len
+ 1], parent
->d_name
.name
,
116 parent
= parent
->d_parent
;
118 strncpy(name
, root
, strlen(root
));
122 static char *inode_name(struct inode
*ino
, int extra
)
124 struct dentry
*dentry
;
126 dentry
= list_entry(ino
->i_dentry
.next
, struct dentry
, d_alias
);
127 return dentry_name(dentry
, extra
);
130 static int read_name(struct inode
*ino
, char *name
)
133 * The non-int inode fields are copied into ints by stat_file and
134 * then copied into the inode because passing the actual pointers
135 * in and having them treated as int * breaks on big-endian machines
138 int i_mode
, i_nlink
, i_blksize
;
139 unsigned long long i_size
;
140 unsigned long long i_ino
;
141 unsigned long long i_blocks
;
143 err
= stat_file(name
, &i_ino
, &i_mode
, &i_nlink
, &ino
->i_uid
,
144 &ino
->i_gid
, &i_size
, &ino
->i_atime
, &ino
->i_mtime
,
145 &ino
->i_ctime
, &i_blksize
, &i_blocks
, -1);
150 ino
->i_mode
= i_mode
;
151 ino
->i_nlink
= i_nlink
;
152 ino
->i_size
= i_size
;
153 ino
->i_blocks
= i_blocks
;
157 static char *follow_link(char *link
)
160 char *name
, *resolved
, *end
;
165 name
= kmalloc(len
, GFP_KERNEL
);
169 n
= do_readlink(link
, name
, len
);
181 end
= strrchr(link
, '/');
186 len
= strlen(link
) + strlen(name
) + 1;
188 resolved
= kmalloc(len
, GFP_KERNEL
);
189 if (resolved
== NULL
) {
194 sprintf(resolved
, "%s%s", link
, name
);
205 static int hostfs_read_inode(struct inode
*ino
)
211 * Unfortunately, we are called from iget() when we don't have a dentry
214 if (list_empty(&ino
->i_dentry
))
218 name
= inode_name(ino
, 0);
222 if (file_type(name
, NULL
, NULL
) == OS_TYPE_SYMLINK
) {
223 name
= follow_link(name
);
230 err
= read_name(ino
, name
);
236 static struct inode
*hostfs_iget(struct super_block
*sb
)
241 inode
= iget_locked(sb
, 0);
243 return ERR_PTR(-ENOMEM
);
244 if (inode
->i_state
& I_NEW
) {
245 ret
= hostfs_read_inode(inode
);
250 unlock_new_inode(inode
);
255 int hostfs_statfs(struct dentry
*dentry
, struct kstatfs
*sf
)
258 * do_statfs uses struct statfs64 internally, but the linux kernel
259 * struct statfs still has 32-bit versions for most of these fields,
260 * so we convert them here
269 err
= do_statfs(HOSTFS_I(dentry
->d_sb
->s_root
->d_inode
)->host_filename
,
270 &sf
->f_bsize
, &f_blocks
, &f_bfree
, &f_bavail
, &f_files
,
271 &f_ffree
, &sf
->f_fsid
, sizeof(sf
->f_fsid
),
272 &sf
->f_namelen
, sf
->f_spare
);
275 sf
->f_blocks
= f_blocks
;
276 sf
->f_bfree
= f_bfree
;
277 sf
->f_bavail
= f_bavail
;
278 sf
->f_files
= f_files
;
279 sf
->f_ffree
= f_ffree
;
280 sf
->f_type
= HOSTFS_SUPER_MAGIC
;
284 static struct inode
*hostfs_alloc_inode(struct super_block
*sb
)
286 struct hostfs_inode_info
*hi
;
288 hi
= kmalloc(sizeof(*hi
), GFP_KERNEL
);
292 *hi
= ((struct hostfs_inode_info
) { .host_filename
= NULL
,
295 inode_init_once(&hi
->vfs_inode
);
296 return &hi
->vfs_inode
;
299 static void hostfs_delete_inode(struct inode
*inode
)
301 truncate_inode_pages(&inode
->i_data
, 0);
302 if (HOSTFS_I(inode
)->fd
!= -1) {
303 close_file(&HOSTFS_I(inode
)->fd
);
304 HOSTFS_I(inode
)->fd
= -1;
309 static void hostfs_destroy_inode(struct inode
*inode
)
311 kfree(HOSTFS_I(inode
)->host_filename
);
314 * XXX: This should not happen, probably. The check is here for
317 if (HOSTFS_I(inode
)->fd
!= -1) {
318 close_file(&HOSTFS_I(inode
)->fd
);
319 printk(KERN_DEBUG
"Closing host fd in .destroy_inode\n");
322 kfree(HOSTFS_I(inode
));
325 static const struct super_operations hostfs_sbops
= {
326 .alloc_inode
= hostfs_alloc_inode
,
327 .drop_inode
= generic_delete_inode
,
328 .delete_inode
= hostfs_delete_inode
,
329 .destroy_inode
= hostfs_destroy_inode
,
330 .statfs
= hostfs_statfs
,
333 int hostfs_readdir(struct file
*file
, void *ent
, filldir_t filldir
)
337 unsigned long long next
, ino
;
340 name
= dentry_name(file
->f_path
.dentry
, 0);
343 dir
= open_dir(name
, &error
);
348 while ((name
= read_dir(dir
, &next
, &ino
, &len
)) != NULL
) {
349 error
= (*filldir
)(ent
, name
, len
, file
->f_pos
,
358 int hostfs_file_open(struct inode
*ino
, struct file
*file
)
361 int mode
= 0, r
= 0, w
= 0, fd
;
363 mode
= file
->f_mode
& (FMODE_READ
| FMODE_WRITE
);
364 if ((mode
& HOSTFS_I(ino
)->mode
) == mode
)
368 * The file may already have been opened, but with the wrong access,
369 * so this resets things and reopens the file with the new access.
371 if (HOSTFS_I(ino
)->fd
!= -1) {
372 close_file(&HOSTFS_I(ino
)->fd
);
373 HOSTFS_I(ino
)->fd
= -1;
376 HOSTFS_I(ino
)->mode
|= mode
;
377 if (HOSTFS_I(ino
)->mode
& FMODE_READ
)
379 if (HOSTFS_I(ino
)->mode
& FMODE_WRITE
)
384 name
= dentry_name(file
->f_path
.dentry
, 0);
388 fd
= open_file(name
, r
, w
, append
);
392 FILE_HOSTFS_I(file
)->fd
= fd
;
397 int hostfs_fsync(struct file
*file
, struct dentry
*dentry
, int datasync
)
399 return fsync_file(HOSTFS_I(dentry
->d_inode
)->fd
, datasync
);
402 static const struct file_operations hostfs_file_fops
= {
403 .llseek
= generic_file_llseek
,
404 .read
= do_sync_read
,
405 .splice_read
= generic_file_splice_read
,
406 .aio_read
= generic_file_aio_read
,
407 .aio_write
= generic_file_aio_write
,
408 .write
= do_sync_write
,
409 .mmap
= generic_file_mmap
,
410 .open
= hostfs_file_open
,
412 .fsync
= hostfs_fsync
,
415 static const struct file_operations hostfs_dir_fops
= {
416 .llseek
= generic_file_llseek
,
417 .readdir
= hostfs_readdir
,
418 .read
= generic_read_dir
,
421 int hostfs_writepage(struct page
*page
, struct writeback_control
*wbc
)
423 struct address_space
*mapping
= page
->mapping
;
424 struct inode
*inode
= mapping
->host
;
426 unsigned long long base
;
427 int count
= PAGE_CACHE_SIZE
;
428 int end_index
= inode
->i_size
>> PAGE_CACHE_SHIFT
;
431 if (page
->index
>= end_index
)
432 count
= inode
->i_size
& (PAGE_CACHE_SIZE
-1);
435 base
= ((unsigned long long) page
->index
) << PAGE_CACHE_SHIFT
;
437 err
= write_file(HOSTFS_I(inode
)->fd
, &base
, buffer
, count
);
439 ClearPageUptodate(page
);
443 if (base
> inode
->i_size
)
444 inode
->i_size
= base
;
447 ClearPageError(page
);
457 int hostfs_readpage(struct file
*file
, struct page
*page
)
463 start
= (long long) page
->index
<< PAGE_CACHE_SHIFT
;
465 err
= read_file(FILE_HOSTFS_I(file
)->fd
, &start
, buffer
,
470 memset(&buffer
[err
], 0, PAGE_CACHE_SIZE
- err
);
472 flush_dcache_page(page
);
473 SetPageUptodate(page
);
474 if (PageError(page
)) ClearPageError(page
);
482 int hostfs_write_begin(struct file
*file
, struct address_space
*mapping
,
483 loff_t pos
, unsigned len
, unsigned flags
,
484 struct page
**pagep
, void **fsdata
)
486 pgoff_t index
= pos
>> PAGE_CACHE_SHIFT
;
488 *pagep
= __grab_cache_page(mapping
, index
);
494 int hostfs_write_end(struct file
*file
, struct address_space
*mapping
,
495 loff_t pos
, unsigned len
, unsigned copied
,
496 struct page
*page
, void *fsdata
)
498 struct inode
*inode
= mapping
->host
;
500 unsigned from
= pos
& (PAGE_CACHE_SIZE
- 1);
504 err
= write_file(FILE_HOSTFS_I(file
)->fd
, &pos
, buffer
+ from
, copied
);
507 if (!PageUptodate(page
) && err
== PAGE_CACHE_SIZE
)
508 SetPageUptodate(page
);
511 * If err > 0, write_file has added err to pos, so we are comparing
512 * i_size against the last byte written.
514 if (err
> 0 && (pos
> inode
->i_size
))
517 page_cache_release(page
);
522 static const struct address_space_operations hostfs_aops
= {
523 .writepage
= hostfs_writepage
,
524 .readpage
= hostfs_readpage
,
525 .set_page_dirty
= __set_page_dirty_nobuffers
,
526 .write_begin
= hostfs_write_begin
,
527 .write_end
= hostfs_write_end
,
530 static int init_inode(struct inode
*inode
, struct dentry
*dentry
)
533 int type
, err
= -ENOMEM
;
538 name
= dentry_name(dentry
, 0);
541 type
= file_type(name
, &maj
, &min
);
542 /* Reencode maj and min with the kernel encoding.*/
543 rdev
= MKDEV(maj
, min
);
546 else type
= OS_TYPE_DIR
;
549 if (type
== OS_TYPE_SYMLINK
)
550 inode
->i_op
= &page_symlink_inode_operations
;
551 else if (type
== OS_TYPE_DIR
)
552 inode
->i_op
= &hostfs_dir_iops
;
553 else inode
->i_op
= &hostfs_iops
;
555 if (type
== OS_TYPE_DIR
) inode
->i_fop
= &hostfs_dir_fops
;
556 else inode
->i_fop
= &hostfs_file_fops
;
558 if (type
== OS_TYPE_SYMLINK
)
559 inode
->i_mapping
->a_ops
= &hostfs_link_aops
;
560 else inode
->i_mapping
->a_ops
= &hostfs_aops
;
563 case OS_TYPE_CHARDEV
:
564 init_special_inode(inode
, S_IFCHR
, rdev
);
566 case OS_TYPE_BLOCKDEV
:
567 init_special_inode(inode
, S_IFBLK
, rdev
);
570 init_special_inode(inode
, S_IFIFO
, 0);
573 init_special_inode(inode
, S_IFSOCK
, 0);
580 int hostfs_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
581 struct nameidata
*nd
)
587 inode
= hostfs_iget(dir
->i_sb
);
589 error
= PTR_ERR(inode
);
593 error
= init_inode(inode
, dentry
);
598 name
= dentry_name(dentry
, 0);
602 fd
= file_create(name
,
603 mode
& S_IRUSR
, mode
& S_IWUSR
, mode
& S_IXUSR
,
604 mode
& S_IRGRP
, mode
& S_IWGRP
, mode
& S_IXGRP
,
605 mode
& S_IROTH
, mode
& S_IWOTH
, mode
& S_IXOTH
);
608 else error
= read_name(inode
, name
);
614 HOSTFS_I(inode
)->fd
= fd
;
615 HOSTFS_I(inode
)->mode
= FMODE_READ
| FMODE_WRITE
;
616 d_instantiate(dentry
, inode
);
625 struct dentry
*hostfs_lookup(struct inode
*ino
, struct dentry
*dentry
,
626 struct nameidata
*nd
)
632 inode
= hostfs_iget(ino
->i_sb
);
634 err
= PTR_ERR(inode
);
638 err
= init_inode(inode
, dentry
);
643 name
= dentry_name(dentry
, 0);
647 err
= read_name(inode
, name
);
649 if (err
== -ENOENT
) {
656 d_add(dentry
, inode
);
657 dentry
->d_op
= &hostfs_dentry_ops
;
666 static char *inode_dentry_name(struct inode
*ino
, struct dentry
*dentry
)
671 file
= inode_name(ino
, dentry
->d_name
.len
+ 1);
676 strncat(file
, dentry
->d_name
.name
, dentry
->d_name
.len
);
677 file
[len
+ dentry
->d_name
.len
] = '\0';
681 int hostfs_link(struct dentry
*to
, struct inode
*ino
, struct dentry
*from
)
683 char *from_name
, *to_name
;
686 if ((from_name
= inode_dentry_name(ino
, from
)) == NULL
)
688 to_name
= dentry_name(to
, 0);
689 if (to_name
== NULL
) {
693 err
= link_file(to_name
, from_name
);
699 int hostfs_unlink(struct inode
*ino
, struct dentry
*dentry
)
704 if ((file
= inode_dentry_name(ino
, dentry
)) == NULL
)
709 err
= unlink_file(file
);
714 int hostfs_symlink(struct inode
*ino
, struct dentry
*dentry
, const char *to
)
719 if ((file
= inode_dentry_name(ino
, dentry
)) == NULL
)
721 err
= make_symlink(file
, to
);
726 int hostfs_mkdir(struct inode
*ino
, struct dentry
*dentry
, int mode
)
731 if ((file
= inode_dentry_name(ino
, dentry
)) == NULL
)
733 err
= do_mkdir(file
, mode
);
738 int hostfs_rmdir(struct inode
*ino
, struct dentry
*dentry
)
743 if ((file
= inode_dentry_name(ino
, dentry
)) == NULL
)
745 err
= do_rmdir(file
);
750 int hostfs_mknod(struct inode
*dir
, struct dentry
*dentry
, int mode
, dev_t dev
)
756 inode
= hostfs_iget(dir
->i_sb
);
758 err
= PTR_ERR(inode
);
762 err
= init_inode(inode
, dentry
);
767 name
= dentry_name(dentry
, 0);
771 init_special_inode(inode
, mode
, dev
);
772 err
= do_mknod(name
, mode
, MAJOR(dev
), MINOR(dev
));
776 err
= read_name(inode
, name
);
781 d_instantiate(dentry
, inode
);
792 int hostfs_rename(struct inode
*from_ino
, struct dentry
*from
,
793 struct inode
*to_ino
, struct dentry
*to
)
795 char *from_name
, *to_name
;
798 if ((from_name
= inode_dentry_name(from_ino
, from
)) == NULL
)
800 if ((to_name
= inode_dentry_name(to_ino
, to
)) == NULL
) {
804 err
= rename_file(from_name
, to_name
);
810 int hostfs_permission(struct inode
*ino
, int desired
, struct nameidata
*nd
)
813 int r
= 0, w
= 0, x
= 0, err
;
815 if (desired
& MAY_READ
) r
= 1;
816 if (desired
& MAY_WRITE
) w
= 1;
817 if (desired
& MAY_EXEC
) x
= 1;
818 name
= inode_name(ino
, 0);
822 if (S_ISCHR(ino
->i_mode
) || S_ISBLK(ino
->i_mode
) ||
823 S_ISFIFO(ino
->i_mode
) || S_ISSOCK(ino
->i_mode
))
826 err
= access_file(name
, r
, w
, x
);
829 err
= generic_permission(ino
, desired
, NULL
);
833 int hostfs_setattr(struct dentry
*dentry
, struct iattr
*attr
)
835 struct hostfs_iattr attrs
;
839 int fd
= HOSTFS_I(dentry
->d_inode
)->fd
;
841 err
= inode_change_ok(dentry
->d_inode
, attr
);
846 attr
->ia_valid
&= ~ATTR_SIZE
;
849 if (attr
->ia_valid
& ATTR_MODE
) {
850 attrs
.ia_valid
|= HOSTFS_ATTR_MODE
;
851 attrs
.ia_mode
= attr
->ia_mode
;
853 if (attr
->ia_valid
& ATTR_UID
) {
854 attrs
.ia_valid
|= HOSTFS_ATTR_UID
;
855 attrs
.ia_uid
= attr
->ia_uid
;
857 if (attr
->ia_valid
& ATTR_GID
) {
858 attrs
.ia_valid
|= HOSTFS_ATTR_GID
;
859 attrs
.ia_gid
= attr
->ia_gid
;
861 if (attr
->ia_valid
& ATTR_SIZE
) {
862 attrs
.ia_valid
|= HOSTFS_ATTR_SIZE
;
863 attrs
.ia_size
= attr
->ia_size
;
865 if (attr
->ia_valid
& ATTR_ATIME
) {
866 attrs
.ia_valid
|= HOSTFS_ATTR_ATIME
;
867 attrs
.ia_atime
= attr
->ia_atime
;
869 if (attr
->ia_valid
& ATTR_MTIME
) {
870 attrs
.ia_valid
|= HOSTFS_ATTR_MTIME
;
871 attrs
.ia_mtime
= attr
->ia_mtime
;
873 if (attr
->ia_valid
& ATTR_CTIME
) {
874 attrs
.ia_valid
|= HOSTFS_ATTR_CTIME
;
875 attrs
.ia_ctime
= attr
->ia_ctime
;
877 if (attr
->ia_valid
& ATTR_ATIME_SET
) {
878 attrs
.ia_valid
|= HOSTFS_ATTR_ATIME_SET
;
880 if (attr
->ia_valid
& ATTR_MTIME_SET
) {
881 attrs
.ia_valid
|= HOSTFS_ATTR_MTIME_SET
;
883 name
= dentry_name(dentry
, 0);
886 err
= set_attr(name
, &attrs
, fd
);
891 return inode_setattr(dentry
->d_inode
, attr
);
894 static const struct inode_operations hostfs_iops
= {
895 .create
= hostfs_create
,
897 .unlink
= hostfs_unlink
,
898 .symlink
= hostfs_symlink
,
899 .mkdir
= hostfs_mkdir
,
900 .rmdir
= hostfs_rmdir
,
901 .mknod
= hostfs_mknod
,
902 .rename
= hostfs_rename
,
903 .permission
= hostfs_permission
,
904 .setattr
= hostfs_setattr
,
907 static const struct inode_operations hostfs_dir_iops
= {
908 .create
= hostfs_create
,
909 .lookup
= hostfs_lookup
,
911 .unlink
= hostfs_unlink
,
912 .symlink
= hostfs_symlink
,
913 .mkdir
= hostfs_mkdir
,
914 .rmdir
= hostfs_rmdir
,
915 .mknod
= hostfs_mknod
,
916 .rename
= hostfs_rename
,
917 .permission
= hostfs_permission
,
918 .setattr
= hostfs_setattr
,
921 int hostfs_link_readpage(struct file
*file
, struct page
*page
)
927 name
= inode_name(page
->mapping
->host
, 0);
930 err
= do_readlink(name
, buffer
, PAGE_CACHE_SIZE
);
932 if (err
== PAGE_CACHE_SIZE
)
935 flush_dcache_page(page
);
936 SetPageUptodate(page
);
937 if (PageError(page
)) ClearPageError(page
);
945 static const struct address_space_operations hostfs_link_aops
= {
946 .readpage
= hostfs_link_readpage
,
949 static int hostfs_fill_sb_common(struct super_block
*sb
, void *d
, int silent
)
951 struct inode
*root_inode
;
952 char *host_root_path
, *req_root
= d
;
955 sb
->s_blocksize
= 1024;
956 sb
->s_blocksize_bits
= 10;
957 sb
->s_magic
= HOSTFS_SUPER_MAGIC
;
958 sb
->s_op
= &hostfs_sbops
;
960 /* NULL is printed as <NULL> by sprintf: avoid that. */
961 if (req_root
== NULL
)
965 host_root_path
= kmalloc(strlen(root_ino
) + 1
966 + strlen(req_root
) + 1, GFP_KERNEL
);
967 if (host_root_path
== NULL
)
970 sprintf(host_root_path
, "%s/%s", root_ino
, req_root
);
972 root_inode
= hostfs_iget(sb
);
973 if (IS_ERR(root_inode
)) {
974 err
= PTR_ERR(root_inode
);
978 err
= init_inode(root_inode
, NULL
);
982 HOSTFS_I(root_inode
)->host_filename
= host_root_path
;
984 * Avoid that in the error path, iput(root_inode) frees again
985 * host_root_path through hostfs_destroy_inode!
987 host_root_path
= NULL
;
990 sb
->s_root
= d_alloc_root(root_inode
);
991 if (sb
->s_root
== NULL
)
994 err
= hostfs_read_inode(root_inode
);
996 /* No iput in this case because the dput does that for us */
1007 kfree(host_root_path
);
1012 static int hostfs_read_sb(struct file_system_type
*type
,
1013 int flags
, const char *dev_name
,
1014 void *data
, struct vfsmount
*mnt
)
1016 return get_sb_nodev(type
, flags
, data
, hostfs_fill_sb_common
, mnt
);
1019 static struct file_system_type hostfs_type
= {
1020 .owner
= THIS_MODULE
,
1022 .get_sb
= hostfs_read_sb
,
1023 .kill_sb
= kill_anon_super
,
1027 static int __init
init_hostfs(void)
1029 return register_filesystem(&hostfs_type
);
1032 static void __exit
exit_hostfs(void)
1034 unregister_filesystem(&hostfs_type
);
1037 module_init(init_hostfs
)
1038 module_exit(exit_hostfs
)
1039 MODULE_LICENSE("GPL");