4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * Some corrections by tytso.
11 /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname
14 /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture.
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
21 #include <linux/namei.h>
22 #include <linux/quotaops.h>
23 #include <linux/pagemap.h>
24 #include <linux/fsnotify.h>
25 #include <linux/smp_lock.h>
26 #include <linux/personality.h>
27 #include <linux/security.h>
28 #include <linux/syscalls.h>
29 #include <linux/mount.h>
30 #include <linux/audit.h>
31 #include <linux/capability.h>
32 #include <linux/file.h>
33 #include <linux/fcntl.h>
34 #include <linux/namei.h>
35 #include <asm/namei.h>
36 #include <asm/uaccess.h>
38 #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
40 /* [Feb-1997 T. Schoebel-Theuer]
41 * Fundamental changes in the pathname lookup mechanisms (namei)
42 * were necessary because of omirr. The reason is that omirr needs
43 * to know the _real_ pathname, not the user-supplied one, in case
44 * of symlinks (and also when transname replacements occur).
46 * The new code replaces the old recursive symlink resolution with
47 * an iterative one (in case of non-nested symlink chains). It does
48 * this with calls to <fs>_follow_link().
49 * As a side effect, dir_namei(), _namei() and follow_link() are now
50 * replaced with a single function lookup_dentry() that can handle all
51 * the special cases of the former code.
53 * With the new dcache, the pathname is stored at each inode, at least as
54 * long as the refcount of the inode is positive. As a side effect, the
55 * size of the dcache depends on the inode cache and thus is dynamic.
57 * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
58 * resolution to correspond with current state of the code.
60 * Note that the symlink resolution is not *completely* iterative.
61 * There is still a significant amount of tail- and mid- recursion in
62 * the algorithm. Also, note that <fs>_readlink() is not used in
63 * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
64 * may return different results than <fs>_follow_link(). Many virtual
65 * filesystems (including /proc) exhibit this behavior.
68 /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
69 * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
70 * and the name already exists in form of a symlink, try to create the new
71 * name indicated by the symlink. The old code always complained that the
72 * name already exists, due to not following the symlink even if its target
73 * is nonexistent. The new semantics affects also mknod() and link() when
74 * the name is a symlink pointing to a non-existant name.
76 * I don't know which semantics is the right one, since I have no access
77 * to standards. But I found by trial that HP-UX 9.0 has the full "new"
78 * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
79 * "old" one. Personally, I think the new semantics is much more logical.
80 * Note that "ln old new" where "new" is a symlink pointing to a non-existing
81 * file does succeed in both HP-UX and SunOs, but not in Solaris
82 * and in the old Linux semantics.
85 /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
86 * semantics. See the comments in "open_namei" and "do_link" below.
88 * [10-Sep-98 Alan Modra] Another symlink change.
91 /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
92 * inside the path - always follow.
93 * in the last component in creation/removal/renaming - never follow.
94 * if LOOKUP_FOLLOW passed - follow.
95 * if the pathname has trailing slashes - follow.
96 * otherwise - don't follow.
97 * (applied in that order).
99 * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
100 * restored for 2.4. This is the last surviving part of old 4.2BSD bug.
101 * During the 2.4 we need to fix the userland stuff depending on it -
102 * hopefully we will be able to get rid of that wart in 2.5. So far only
103 * XEmacs seems to be relying on it...
106 * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
107 * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
108 * any extra contention...
111 /* In order to reduce some races, while at the same time doing additional
112 * checking and hopefully speeding things up, we copy filenames to the
113 * kernel data space before using them..
115 * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
116 * PATH_MAX includes the nul terminator --RR.
118 static int do_getname(const char __user
*filename
, char *page
)
121 unsigned long len
= PATH_MAX
;
123 if (!segment_eq(get_fs(), KERNEL_DS
)) {
124 if ((unsigned long) filename
>= TASK_SIZE
)
126 if (TASK_SIZE
- (unsigned long) filename
< PATH_MAX
)
127 len
= TASK_SIZE
- (unsigned long) filename
;
130 retval
= strncpy_from_user(page
, filename
, len
);
134 return -ENAMETOOLONG
;
140 char * getname(const char __user
* filename
)
144 result
= ERR_PTR(-ENOMEM
);
147 int retval
= do_getname(filename
, tmp
);
152 result
= ERR_PTR(retval
);
155 audit_getname(result
);
159 #ifdef CONFIG_AUDITSYSCALL
160 void putname(const char *name
)
162 if (unlikely(current
->audit_context
))
167 EXPORT_SYMBOL(putname
);
172 * generic_permission - check for access rights on a Posix-like filesystem
173 * @inode: inode to check access rights for
174 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
175 * @check_acl: optional callback to check for Posix ACLs
177 * Used to check for read/write/execute permissions on a file.
178 * We use "fsuid" for this, letting us set arbitrary permissions
179 * for filesystem access without changing the "normal" uids which
180 * are used for other things..
182 int generic_permission(struct inode
*inode
, int mask
,
183 int (*check_acl
)(struct inode
*inode
, int mask
))
185 umode_t mode
= inode
->i_mode
;
187 if (current
->fsuid
== inode
->i_uid
)
190 if (IS_POSIXACL(inode
) && (mode
& S_IRWXG
) && check_acl
) {
191 int error
= check_acl(inode
, mask
);
192 if (error
== -EACCES
)
193 goto check_capabilities
;
194 else if (error
!= -EAGAIN
)
198 if (in_group_p(inode
->i_gid
))
203 * If the DACs are ok we don't need any capability check.
205 if (((mode
& mask
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
)) == mask
))
210 * Read/write DACs are always overridable.
211 * Executable DACs are overridable if at least one exec bit is set.
213 if (!(mask
& MAY_EXEC
) ||
214 (inode
->i_mode
& S_IXUGO
) || S_ISDIR(inode
->i_mode
))
215 if (capable(CAP_DAC_OVERRIDE
))
219 * Searching includes executable on directories, else just read.
221 if (mask
== MAY_READ
|| (S_ISDIR(inode
->i_mode
) && !(mask
& MAY_WRITE
)))
222 if (capable(CAP_DAC_READ_SEARCH
))
228 int permission(struct inode
*inode
, int mask
, struct nameidata
*nd
)
232 if (mask
& MAY_WRITE
) {
233 umode_t mode
= inode
->i_mode
;
236 * Nobody gets write access to a read-only fs.
238 if (IS_RDONLY(inode
) &&
239 (S_ISREG(mode
) || S_ISDIR(mode
) || S_ISLNK(mode
)))
243 * Nobody gets write access to an immutable file.
245 if (IS_IMMUTABLE(inode
))
250 /* Ordinary permission routines do not understand MAY_APPEND. */
251 submask
= mask
& ~MAY_APPEND
;
252 if (inode
->i_op
&& inode
->i_op
->permission
)
253 retval
= inode
->i_op
->permission(inode
, submask
, nd
);
255 retval
= generic_permission(inode
, submask
, NULL
);
259 return security_inode_permission(inode
, mask
, nd
);
263 * vfs_permission - check for access rights to a given path
264 * @nd: lookup result that describes the path
265 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
267 * Used to check for read/write/execute permissions on a path.
268 * We use "fsuid" for this, letting us set arbitrary permissions
269 * for filesystem access without changing the "normal" uids which
270 * are used for other things.
272 int vfs_permission(struct nameidata
*nd
, int mask
)
274 return permission(nd
->dentry
->d_inode
, mask
, nd
);
278 * file_permission - check for additional access rights to a given file
279 * @file: file to check access rights for
280 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
282 * Used to check for read/write/execute permissions on an already opened
286 * Do not use this function in new code. All access checks should
287 * be done using vfs_permission().
289 int file_permission(struct file
*file
, int mask
)
291 return permission(file
->f_dentry
->d_inode
, mask
, NULL
);
295 * get_write_access() gets write permission for a file.
296 * put_write_access() releases this write permission.
297 * This is used for regular files.
298 * We cannot support write (and maybe mmap read-write shared) accesses and
299 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
300 * can have the following values:
301 * 0: no writers, no VM_DENYWRITE mappings
302 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
303 * > 0: (i_writecount) users are writing to the file.
305 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
306 * except for the cases where we don't hold i_writecount yet. Then we need to
307 * use {get,deny}_write_access() - these functions check the sign and refuse
308 * to do the change if sign is wrong. Exclusion between them is provided by
309 * the inode->i_lock spinlock.
312 int get_write_access(struct inode
* inode
)
314 spin_lock(&inode
->i_lock
);
315 if (atomic_read(&inode
->i_writecount
) < 0) {
316 spin_unlock(&inode
->i_lock
);
319 atomic_inc(&inode
->i_writecount
);
320 spin_unlock(&inode
->i_lock
);
325 int deny_write_access(struct file
* file
)
327 struct inode
*inode
= file
->f_dentry
->d_inode
;
329 spin_lock(&inode
->i_lock
);
330 if (atomic_read(&inode
->i_writecount
) > 0) {
331 spin_unlock(&inode
->i_lock
);
334 atomic_dec(&inode
->i_writecount
);
335 spin_unlock(&inode
->i_lock
);
340 void path_release(struct nameidata
*nd
)
347 * umount() mustn't call path_release()/mntput() as that would clear
350 void path_release_on_umount(struct nameidata
*nd
)
353 mntput_no_expire(nd
->mnt
);
357 * release_open_intent - free up open intent resources
358 * @nd: pointer to nameidata
360 void release_open_intent(struct nameidata
*nd
)
362 if (nd
->intent
.open
.file
->f_dentry
== NULL
)
363 put_filp(nd
->intent
.open
.file
);
365 fput(nd
->intent
.open
.file
);
369 * Internal lookup() using the new generic dcache.
372 static struct dentry
* cached_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
374 struct dentry
* dentry
= __d_lookup(parent
, name
);
376 /* lockess __d_lookup may fail due to concurrent d_move()
377 * in some unrelated directory, so try with d_lookup
380 dentry
= d_lookup(parent
, name
);
382 if (dentry
&& dentry
->d_op
&& dentry
->d_op
->d_revalidate
) {
383 if (!dentry
->d_op
->d_revalidate(dentry
, nd
) && !d_invalidate(dentry
)) {
392 * Short-cut version of permission(), for calling by
393 * path_walk(), when dcache lock is held. Combines parts
394 * of permission() and generic_permission(), and tests ONLY for
395 * MAY_EXEC permission.
397 * If appropriate, check DAC only. If not appropriate, or
398 * short-cut DAC fails, then call permission() to do more
399 * complete permission check.
401 static int exec_permission_lite(struct inode
*inode
,
402 struct nameidata
*nd
)
404 umode_t mode
= inode
->i_mode
;
406 if (inode
->i_op
&& inode
->i_op
->permission
)
409 if (current
->fsuid
== inode
->i_uid
)
411 else if (in_group_p(inode
->i_gid
))
417 if ((inode
->i_mode
& S_IXUGO
) && capable(CAP_DAC_OVERRIDE
))
420 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_OVERRIDE
))
423 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_READ_SEARCH
))
428 return security_inode_permission(inode
, MAY_EXEC
, nd
);
432 * This is called when everything else fails, and we actually have
433 * to go to the low-level filesystem to find out what we should do..
435 * We get the directory semaphore, and after getting that we also
436 * make sure that nobody added the entry to the dcache in the meantime..
439 static struct dentry
* real_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
441 struct dentry
* result
;
442 struct inode
*dir
= parent
->d_inode
;
444 mutex_lock(&dir
->i_mutex
);
446 * First re-do the cached lookup just in case it was created
447 * while we waited for the directory semaphore..
449 * FIXME! This could use version numbering or similar to
450 * avoid unnecessary cache lookups.
452 * The "dcache_lock" is purely to protect the RCU list walker
453 * from concurrent renames at this point (we mustn't get false
454 * negatives from the RCU list walk here, unlike the optimistic
457 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
459 result
= d_lookup(parent
, name
);
461 struct dentry
* dentry
= d_alloc(parent
, name
);
462 result
= ERR_PTR(-ENOMEM
);
464 result
= dir
->i_op
->lookup(dir
, dentry
, nd
);
470 mutex_unlock(&dir
->i_mutex
);
475 * Uhhuh! Nasty case: the cache was re-populated while
476 * we waited on the semaphore. Need to revalidate.
478 mutex_unlock(&dir
->i_mutex
);
479 if (result
->d_op
&& result
->d_op
->d_revalidate
) {
480 if (!result
->d_op
->d_revalidate(result
, nd
) && !d_invalidate(result
)) {
482 result
= ERR_PTR(-ENOENT
);
488 static int __emul_lookup_dentry(const char *, struct nameidata
*);
491 static __always_inline
int
492 walk_init_root(const char *name
, struct nameidata
*nd
)
494 read_lock(¤t
->fs
->lock
);
495 if (current
->fs
->altroot
&& !(nd
->flags
& LOOKUP_NOALT
)) {
496 nd
->mnt
= mntget(current
->fs
->altrootmnt
);
497 nd
->dentry
= dget(current
->fs
->altroot
);
498 read_unlock(¤t
->fs
->lock
);
499 if (__emul_lookup_dentry(name
,nd
))
501 read_lock(¤t
->fs
->lock
);
503 nd
->mnt
= mntget(current
->fs
->rootmnt
);
504 nd
->dentry
= dget(current
->fs
->root
);
505 read_unlock(¤t
->fs
->lock
);
509 static __always_inline
int __vfs_follow_link(struct nameidata
*nd
, const char *link
)
518 if (!walk_init_root(link
, nd
))
519 /* weird __emul_prefix() stuff did it */
522 res
= link_path_walk(link
, nd
);
524 if (nd
->depth
|| res
|| nd
->last_type
!=LAST_NORM
)
527 * If it is an iterative symlinks resolution in open_namei() we
528 * have to copy the last component. And all that crap because of
529 * bloody create() on broken symlinks. Furrfu...
532 if (unlikely(!name
)) {
536 strcpy(name
, nd
->last
.name
);
537 nd
->last
.name
= name
;
541 return PTR_ERR(link
);
545 struct vfsmount
*mnt
;
546 struct dentry
*dentry
;
549 static __always_inline
int __do_follow_link(struct path
*path
, struct nameidata
*nd
)
553 struct dentry
*dentry
= path
->dentry
;
555 touch_atime(path
->mnt
, dentry
);
556 nd_set_link(nd
, NULL
);
558 if (path
->mnt
== nd
->mnt
)
560 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, nd
);
561 error
= PTR_ERR(cookie
);
562 if (!IS_ERR(cookie
)) {
563 char *s
= nd_get_link(nd
);
566 error
= __vfs_follow_link(nd
, s
);
567 if (dentry
->d_inode
->i_op
->put_link
)
568 dentry
->d_inode
->i_op
->put_link(dentry
, nd
, cookie
);
576 static inline void dput_path(struct path
*path
, struct nameidata
*nd
)
579 if (path
->mnt
!= nd
->mnt
)
583 static inline void path_to_nameidata(struct path
*path
, struct nameidata
*nd
)
586 if (nd
->mnt
!= path
->mnt
)
589 nd
->dentry
= path
->dentry
;
593 * This limits recursive symlink follows to 8, while
594 * limiting consecutive symlinks to 40.
596 * Without that kind of total limit, nasty chains of consecutive
597 * symlinks can cause almost arbitrarily long lookups.
599 static inline int do_follow_link(struct path
*path
, struct nameidata
*nd
)
602 if (current
->link_count
>= MAX_NESTED_LINKS
)
604 if (current
->total_link_count
>= 40)
606 BUG_ON(nd
->depth
>= MAX_NESTED_LINKS
);
608 err
= security_inode_follow_link(path
->dentry
, nd
);
611 current
->link_count
++;
612 current
->total_link_count
++;
614 err
= __do_follow_link(path
, nd
);
615 current
->link_count
--;
624 int follow_up(struct vfsmount
**mnt
, struct dentry
**dentry
)
626 struct vfsmount
*parent
;
627 struct dentry
*mountpoint
;
628 spin_lock(&vfsmount_lock
);
629 parent
=(*mnt
)->mnt_parent
;
630 if (parent
== *mnt
) {
631 spin_unlock(&vfsmount_lock
);
635 mountpoint
=dget((*mnt
)->mnt_mountpoint
);
636 spin_unlock(&vfsmount_lock
);
638 *dentry
= mountpoint
;
644 /* no need for dcache_lock, as serialization is taken care in
647 static int __follow_mount(struct path
*path
)
650 while (d_mountpoint(path
->dentry
)) {
651 struct vfsmount
*mounted
= lookup_mnt(path
->mnt
, path
->dentry
);
658 path
->dentry
= dget(mounted
->mnt_root
);
664 static void follow_mount(struct vfsmount
**mnt
, struct dentry
**dentry
)
666 while (d_mountpoint(*dentry
)) {
667 struct vfsmount
*mounted
= lookup_mnt(*mnt
, *dentry
);
673 *dentry
= dget(mounted
->mnt_root
);
677 /* no need for dcache_lock, as serialization is taken care in
680 int follow_down(struct vfsmount
**mnt
, struct dentry
**dentry
)
682 struct vfsmount
*mounted
;
684 mounted
= lookup_mnt(*mnt
, *dentry
);
689 *dentry
= dget(mounted
->mnt_root
);
695 static __always_inline
void follow_dotdot(struct nameidata
*nd
)
698 struct vfsmount
*parent
;
699 struct dentry
*old
= nd
->dentry
;
701 read_lock(¤t
->fs
->lock
);
702 if (nd
->dentry
== current
->fs
->root
&&
703 nd
->mnt
== current
->fs
->rootmnt
) {
704 read_unlock(¤t
->fs
->lock
);
707 read_unlock(¤t
->fs
->lock
);
708 spin_lock(&dcache_lock
);
709 if (nd
->dentry
!= nd
->mnt
->mnt_root
) {
710 nd
->dentry
= dget(nd
->dentry
->d_parent
);
711 spin_unlock(&dcache_lock
);
715 spin_unlock(&dcache_lock
);
716 spin_lock(&vfsmount_lock
);
717 parent
= nd
->mnt
->mnt_parent
;
718 if (parent
== nd
->mnt
) {
719 spin_unlock(&vfsmount_lock
);
723 nd
->dentry
= dget(nd
->mnt
->mnt_mountpoint
);
724 spin_unlock(&vfsmount_lock
);
729 follow_mount(&nd
->mnt
, &nd
->dentry
);
733 * It's more convoluted than I'd like it to be, but... it's still fairly
734 * small and for now I'd prefer to have fast path as straight as possible.
735 * It _is_ time-critical.
737 static int do_lookup(struct nameidata
*nd
, struct qstr
*name
,
740 struct vfsmount
*mnt
= nd
->mnt
;
741 struct dentry
*dentry
= __d_lookup(nd
->dentry
, name
);
745 if (dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
746 goto need_revalidate
;
749 path
->dentry
= dentry
;
750 __follow_mount(path
);
754 dentry
= real_lookup(nd
->dentry
, name
, nd
);
760 if (dentry
->d_op
->d_revalidate(dentry
, nd
))
762 if (d_invalidate(dentry
))
768 return PTR_ERR(dentry
);
773 * This is the basic name resolution function, turning a pathname into
774 * the final dentry. We expect 'base' to be positive and a directory.
776 * Returns 0 and nd will have valid dentry and mnt on success.
777 * Returns error and drops reference to input namei data on failure.
779 static fastcall
int __link_path_walk(const char * name
, struct nameidata
*nd
)
784 unsigned int lookup_flags
= nd
->flags
;
791 inode
= nd
->dentry
->d_inode
;
793 lookup_flags
= LOOKUP_FOLLOW
| (nd
->flags
& LOOKUP_CONTINUE
);
795 /* At this point we know we have a real path component. */
801 nd
->flags
|= LOOKUP_CONTINUE
;
802 err
= exec_permission_lite(inode
, nd
);
804 err
= vfs_permission(nd
, MAY_EXEC
);
809 c
= *(const unsigned char *)name
;
811 hash
= init_name_hash();
814 hash
= partial_name_hash(c
, hash
);
815 c
= *(const unsigned char *)name
;
816 } while (c
&& (c
!= '/'));
817 this.len
= name
- (const char *) this.name
;
818 this.hash
= end_name_hash(hash
);
820 /* remove trailing slashes? */
823 while (*++name
== '/');
825 goto last_with_slashes
;
828 * "." and ".." are special - ".." especially so because it has
829 * to be able to know about the current root directory and
830 * parent relationships.
832 if (this.name
[0] == '.') switch (this.len
) {
836 if (this.name
[1] != '.')
839 inode
= nd
->dentry
->d_inode
;
845 * See if the low-level filesystem might want
846 * to use its own hash..
848 if (nd
->dentry
->d_op
&& nd
->dentry
->d_op
->d_hash
) {
849 err
= nd
->dentry
->d_op
->d_hash(nd
->dentry
, &this);
853 /* This does the actual lookups.. */
854 err
= do_lookup(nd
, &this, &next
);
859 inode
= next
.dentry
->d_inode
;
866 if (inode
->i_op
->follow_link
) {
867 err
= do_follow_link(&next
, nd
);
871 inode
= nd
->dentry
->d_inode
;
878 path_to_nameidata(&next
, nd
);
880 if (!inode
->i_op
->lookup
)
883 /* here ends the main loop */
886 lookup_flags
|= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
888 /* Clear LOOKUP_CONTINUE iff it was previously unset */
889 nd
->flags
&= lookup_flags
| ~LOOKUP_CONTINUE
;
890 if (lookup_flags
& LOOKUP_PARENT
)
892 if (this.name
[0] == '.') switch (this.len
) {
896 if (this.name
[1] != '.')
899 inode
= nd
->dentry
->d_inode
;
904 if (nd
->dentry
->d_op
&& nd
->dentry
->d_op
->d_hash
) {
905 err
= nd
->dentry
->d_op
->d_hash(nd
->dentry
, &this);
909 err
= do_lookup(nd
, &this, &next
);
912 inode
= next
.dentry
->d_inode
;
913 if ((lookup_flags
& LOOKUP_FOLLOW
)
914 && inode
&& inode
->i_op
&& inode
->i_op
->follow_link
) {
915 err
= do_follow_link(&next
, nd
);
918 inode
= nd
->dentry
->d_inode
;
920 path_to_nameidata(&next
, nd
);
924 if (lookup_flags
& LOOKUP_DIRECTORY
) {
926 if (!inode
->i_op
|| !inode
->i_op
->lookup
)
932 nd
->last_type
= LAST_NORM
;
933 if (this.name
[0] != '.')
936 nd
->last_type
= LAST_DOT
;
937 else if (this.len
== 2 && this.name
[1] == '.')
938 nd
->last_type
= LAST_DOTDOT
;
943 * We bypassed the ordinary revalidation routines.
944 * We may need to check the cached dentry for staleness.
946 if (nd
->dentry
&& nd
->dentry
->d_sb
&&
947 (nd
->dentry
->d_sb
->s_type
->fs_flags
& FS_REVAL_DOT
)) {
949 /* Note: we do not d_invalidate() */
950 if (!nd
->dentry
->d_op
->d_revalidate(nd
->dentry
, nd
))
956 dput_path(&next
, nd
);
965 * Wrapper to retry pathname resolution whenever the underlying
966 * file system returns an ESTALE.
968 * Retry the whole path once, forcing real lookup requests
969 * instead of relying on the dcache.
971 int fastcall
link_path_walk(const char *name
, struct nameidata
*nd
)
973 struct nameidata save
= *nd
;
976 /* make sure the stuff we saved doesn't go away */
980 result
= __link_path_walk(name
, nd
);
981 if (result
== -ESTALE
) {
985 nd
->flags
|= LOOKUP_REVAL
;
986 result
= __link_path_walk(name
, nd
);
995 int fastcall
path_walk(const char * name
, struct nameidata
*nd
)
997 current
->total_link_count
= 0;
998 return link_path_walk(name
, nd
);
1002 * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
1003 * everything is done. Returns 0 and drops input nd, if lookup failed;
1005 static int __emul_lookup_dentry(const char *name
, struct nameidata
*nd
)
1007 if (path_walk(name
, nd
))
1008 return 0; /* something went wrong... */
1010 if (!nd
->dentry
->d_inode
|| S_ISDIR(nd
->dentry
->d_inode
->i_mode
)) {
1011 struct dentry
*old_dentry
= nd
->dentry
;
1012 struct vfsmount
*old_mnt
= nd
->mnt
;
1013 struct qstr last
= nd
->last
;
1014 int last_type
= nd
->last_type
;
1016 * NAME was not found in alternate root or it's a directory. Try to find
1017 * it in the normal root:
1019 nd
->last_type
= LAST_ROOT
;
1020 read_lock(¤t
->fs
->lock
);
1021 nd
->mnt
= mntget(current
->fs
->rootmnt
);
1022 nd
->dentry
= dget(current
->fs
->root
);
1023 read_unlock(¤t
->fs
->lock
);
1024 if (path_walk(name
, nd
) == 0) {
1025 if (nd
->dentry
->d_inode
) {
1032 nd
->dentry
= old_dentry
;
1035 nd
->last_type
= last_type
;
1040 void set_fs_altroot(void)
1042 char *emul
= __emul_prefix();
1043 struct nameidata nd
;
1044 struct vfsmount
*mnt
= NULL
, *oldmnt
;
1045 struct dentry
*dentry
= NULL
, *olddentry
;
1050 err
= path_lookup(emul
, LOOKUP_FOLLOW
|LOOKUP_DIRECTORY
|LOOKUP_NOALT
, &nd
);
1056 write_lock(¤t
->fs
->lock
);
1057 oldmnt
= current
->fs
->altrootmnt
;
1058 olddentry
= current
->fs
->altroot
;
1059 current
->fs
->altrootmnt
= mnt
;
1060 current
->fs
->altroot
= dentry
;
1061 write_unlock(¤t
->fs
->lock
);
1068 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
1069 static int fastcall
do_path_lookup(int dfd
, const char *name
,
1070 unsigned int flags
, struct nameidata
*nd
)
1076 nd
->last_type
= LAST_ROOT
; /* if there are only slashes... */
1080 read_lock(¤t
->fs
->lock
);
1082 if (current
->fs
->altroot
&& !(nd
->flags
& LOOKUP_NOALT
)) {
1083 nd
->mnt
= mntget(current
->fs
->altrootmnt
);
1084 nd
->dentry
= dget(current
->fs
->altroot
);
1085 read_unlock(¤t
->fs
->lock
);
1086 if (__emul_lookup_dentry(name
,nd
))
1087 goto out
; /* found in altroot */
1088 read_lock(¤t
->fs
->lock
);
1090 nd
->mnt
= mntget(current
->fs
->rootmnt
);
1091 nd
->dentry
= dget(current
->fs
->root
);
1092 } else if (dfd
== AT_FDCWD
) {
1093 nd
->mnt
= mntget(current
->fs
->pwdmnt
);
1094 nd
->dentry
= dget(current
->fs
->pwd
);
1096 struct dentry
*dentry
;
1098 file
= fget_light(dfd
, &fput_needed
);
1103 dentry
= file
->f_dentry
;
1106 if (!S_ISDIR(dentry
->d_inode
->i_mode
))
1107 goto fput_unlock_fail
;
1109 retval
= file_permission(file
, MAY_EXEC
);
1111 goto fput_unlock_fail
;
1113 nd
->mnt
= mntget(file
->f_vfsmnt
);
1114 nd
->dentry
= dget(dentry
);
1116 fput_light(file
, fput_needed
);
1118 read_unlock(¤t
->fs
->lock
);
1119 current
->total_link_count
= 0;
1120 retval
= link_path_walk(name
, nd
);
1122 if (likely(retval
== 0)) {
1123 if (unlikely(current
->audit_context
&& nd
&& nd
->dentry
&&
1124 nd
->dentry
->d_inode
))
1125 audit_inode(name
, nd
->dentry
->d_inode
, flags
);
1130 fput_light(file
, fput_needed
);
1132 read_unlock(¤t
->fs
->lock
);
1136 int fastcall
path_lookup(const char *name
, unsigned int flags
,
1137 struct nameidata
*nd
)
1139 return do_path_lookup(AT_FDCWD
, name
, flags
, nd
);
1142 static int __path_lookup_intent_open(int dfd
, const char *name
,
1143 unsigned int lookup_flags
, struct nameidata
*nd
,
1144 int open_flags
, int create_mode
)
1146 struct file
*filp
= get_empty_filp();
1151 nd
->intent
.open
.file
= filp
;
1152 nd
->intent
.open
.flags
= open_flags
;
1153 nd
->intent
.open
.create_mode
= create_mode
;
1154 err
= do_path_lookup(dfd
, name
, lookup_flags
|LOOKUP_OPEN
, nd
);
1155 if (IS_ERR(nd
->intent
.open
.file
)) {
1157 err
= PTR_ERR(nd
->intent
.open
.file
);
1160 } else if (err
!= 0)
1161 release_open_intent(nd
);
1166 * path_lookup_open - lookup a file path with open intent
1167 * @dfd: the directory to use as base, or AT_FDCWD
1168 * @name: pointer to file name
1169 * @lookup_flags: lookup intent flags
1170 * @nd: pointer to nameidata
1171 * @open_flags: open intent flags
1173 int path_lookup_open(int dfd
, const char *name
, unsigned int lookup_flags
,
1174 struct nameidata
*nd
, int open_flags
)
1176 return __path_lookup_intent_open(dfd
, name
, lookup_flags
, nd
,
1181 * path_lookup_create - lookup a file path with open + create intent
1182 * @dfd: the directory to use as base, or AT_FDCWD
1183 * @name: pointer to file name
1184 * @lookup_flags: lookup intent flags
1185 * @nd: pointer to nameidata
1186 * @open_flags: open intent flags
1187 * @create_mode: create intent flags
1189 static int path_lookup_create(int dfd
, const char *name
,
1190 unsigned int lookup_flags
, struct nameidata
*nd
,
1191 int open_flags
, int create_mode
)
1193 return __path_lookup_intent_open(dfd
, name
, lookup_flags
|LOOKUP_CREATE
,
1194 nd
, open_flags
, create_mode
);
1197 int __user_path_lookup_open(const char __user
*name
, unsigned int lookup_flags
,
1198 struct nameidata
*nd
, int open_flags
)
1200 char *tmp
= getname(name
);
1201 int err
= PTR_ERR(tmp
);
1204 err
= __path_lookup_intent_open(AT_FDCWD
, tmp
, lookup_flags
, nd
, open_flags
, 0);
1211 * Restricted form of lookup. Doesn't follow links, single-component only,
1212 * needs parent already locked. Doesn't follow mounts.
1215 static struct dentry
* __lookup_hash(struct qstr
*name
, struct dentry
* base
, struct nameidata
*nd
)
1217 struct dentry
* dentry
;
1218 struct inode
*inode
;
1221 inode
= base
->d_inode
;
1222 err
= permission(inode
, MAY_EXEC
, nd
);
1223 dentry
= ERR_PTR(err
);
1228 * See if the low-level filesystem might want
1229 * to use its own hash..
1231 if (base
->d_op
&& base
->d_op
->d_hash
) {
1232 err
= base
->d_op
->d_hash(base
, name
);
1233 dentry
= ERR_PTR(err
);
1238 dentry
= cached_lookup(base
, name
, nd
);
1240 struct dentry
*new = d_alloc(base
, name
);
1241 dentry
= ERR_PTR(-ENOMEM
);
1244 dentry
= inode
->i_op
->lookup(inode
, new, nd
);
1254 struct dentry
* lookup_hash(struct nameidata
*nd
)
1256 return __lookup_hash(&nd
->last
, nd
->dentry
, nd
);
1260 struct dentry
* lookup_one_len(const char * name
, struct dentry
* base
, int len
)
1271 hash
= init_name_hash();
1273 c
= *(const unsigned char *)name
++;
1274 if (c
== '/' || c
== '\0')
1276 hash
= partial_name_hash(c
, hash
);
1278 this.hash
= end_name_hash(hash
);
1280 return __lookup_hash(&this, base
, NULL
);
1282 return ERR_PTR(-EACCES
);
1288 * is used by most simple commands to get the inode of a specified name.
1289 * Open, link etc use their own routines, but this is enough for things
1292 * namei exists in two versions: namei/lnamei. The only difference is
1293 * that namei follows links, while lnamei does not.
1296 int fastcall
__user_walk_fd(int dfd
, const char __user
*name
, unsigned flags
,
1297 struct nameidata
*nd
)
1299 char *tmp
= getname(name
);
1300 int err
= PTR_ERR(tmp
);
1303 err
= do_path_lookup(dfd
, tmp
, flags
, nd
);
1309 int fastcall
__user_walk(const char __user
*name
, unsigned flags
, struct nameidata
*nd
)
1311 return __user_walk_fd(AT_FDCWD
, name
, flags
, nd
);
1315 * It's inline, so penalty for filesystems that don't use sticky bit is
1318 static inline int check_sticky(struct inode
*dir
, struct inode
*inode
)
1320 if (!(dir
->i_mode
& S_ISVTX
))
1322 if (inode
->i_uid
== current
->fsuid
)
1324 if (dir
->i_uid
== current
->fsuid
)
1326 return !capable(CAP_FOWNER
);
1330 * Check whether we can remove a link victim from directory dir, check
1331 * whether the type of victim is right.
1332 * 1. We can't do it if dir is read-only (done in permission())
1333 * 2. We should have write and exec permissions on dir
1334 * 3. We can't remove anything from append-only dir
1335 * 4. We can't do anything with immutable dir (done in permission())
1336 * 5. If the sticky bit on dir is set we should either
1337 * a. be owner of dir, or
1338 * b. be owner of victim, or
1339 * c. have CAP_FOWNER capability
1340 * 6. If the victim is append-only or immutable we can't do antyhing with
1341 * links pointing to it.
1342 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1343 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1344 * 9. We can't remove a root or mountpoint.
1345 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1346 * nfs_async_unlink().
1348 static int may_delete(struct inode
*dir
,struct dentry
*victim
,int isdir
)
1352 if (!victim
->d_inode
)
1355 BUG_ON(victim
->d_parent
->d_inode
!= dir
);
1357 error
= permission(dir
,MAY_WRITE
| MAY_EXEC
, NULL
);
1362 if (check_sticky(dir
, victim
->d_inode
)||IS_APPEND(victim
->d_inode
)||
1363 IS_IMMUTABLE(victim
->d_inode
))
1366 if (!S_ISDIR(victim
->d_inode
->i_mode
))
1368 if (IS_ROOT(victim
))
1370 } else if (S_ISDIR(victim
->d_inode
->i_mode
))
1372 if (IS_DEADDIR(dir
))
1374 if (victim
->d_flags
& DCACHE_NFSFS_RENAMED
)
1379 /* Check whether we can create an object with dentry child in directory
1381 * 1. We can't do it if child already exists (open has special treatment for
1382 * this case, but since we are inlined it's OK)
1383 * 2. We can't do it if dir is read-only (done in permission())
1384 * 3. We should have write and exec permissions on dir
1385 * 4. We can't do it if dir is immutable (done in permission())
1387 static inline int may_create(struct inode
*dir
, struct dentry
*child
,
1388 struct nameidata
*nd
)
1392 if (IS_DEADDIR(dir
))
1394 return permission(dir
,MAY_WRITE
| MAY_EXEC
, nd
);
1398 * O_DIRECTORY translates into forcing a directory lookup.
1400 static inline int lookup_flags(unsigned int f
)
1402 unsigned long retval
= LOOKUP_FOLLOW
;
1405 retval
&= ~LOOKUP_FOLLOW
;
1407 if (f
& O_DIRECTORY
)
1408 retval
|= LOOKUP_DIRECTORY
;
1414 * p1 and p2 should be directories on the same fs.
1416 struct dentry
*lock_rename(struct dentry
*p1
, struct dentry
*p2
)
1421 mutex_lock(&p1
->d_inode
->i_mutex
);
1425 mutex_lock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1427 for (p
= p1
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1428 if (p
->d_parent
== p2
) {
1429 mutex_lock(&p2
->d_inode
->i_mutex
);
1430 mutex_lock(&p1
->d_inode
->i_mutex
);
1435 for (p
= p2
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1436 if (p
->d_parent
== p1
) {
1437 mutex_lock(&p1
->d_inode
->i_mutex
);
1438 mutex_lock(&p2
->d_inode
->i_mutex
);
1443 mutex_lock(&p1
->d_inode
->i_mutex
);
1444 mutex_lock(&p2
->d_inode
->i_mutex
);
1448 void unlock_rename(struct dentry
*p1
, struct dentry
*p2
)
1450 mutex_unlock(&p1
->d_inode
->i_mutex
);
1452 mutex_unlock(&p2
->d_inode
->i_mutex
);
1453 mutex_unlock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1457 int vfs_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
1458 struct nameidata
*nd
)
1460 int error
= may_create(dir
, dentry
, nd
);
1465 if (!dir
->i_op
|| !dir
->i_op
->create
)
1466 return -EACCES
; /* shouldn't it be ENOSYS? */
1469 error
= security_inode_create(dir
, dentry
, mode
);
1473 error
= dir
->i_op
->create(dir
, dentry
, mode
, nd
);
1475 fsnotify_create(dir
, dentry
->d_name
.name
);
1479 int may_open(struct nameidata
*nd
, int acc_mode
, int flag
)
1481 struct dentry
*dentry
= nd
->dentry
;
1482 struct inode
*inode
= dentry
->d_inode
;
1488 if (S_ISLNK(inode
->i_mode
))
1491 if (S_ISDIR(inode
->i_mode
) && (flag
& FMODE_WRITE
))
1494 error
= vfs_permission(nd
, acc_mode
);
1499 * FIFO's, sockets and device files are special: they don't
1500 * actually live on the filesystem itself, and as such you
1501 * can write to them even if the filesystem is read-only.
1503 if (S_ISFIFO(inode
->i_mode
) || S_ISSOCK(inode
->i_mode
)) {
1505 } else if (S_ISBLK(inode
->i_mode
) || S_ISCHR(inode
->i_mode
)) {
1506 if (nd
->mnt
->mnt_flags
& MNT_NODEV
)
1510 } else if (IS_RDONLY(inode
) && (flag
& FMODE_WRITE
))
1513 * An append-only file must be opened in append mode for writing.
1515 if (IS_APPEND(inode
)) {
1516 if ((flag
& FMODE_WRITE
) && !(flag
& O_APPEND
))
1522 /* O_NOATIME can only be set by the owner or superuser */
1523 if (flag
& O_NOATIME
)
1524 if (current
->fsuid
!= inode
->i_uid
&& !capable(CAP_FOWNER
))
1528 * Ensure there are no outstanding leases on the file.
1530 error
= break_lease(inode
, flag
);
1534 if (flag
& O_TRUNC
) {
1535 error
= get_write_access(inode
);
1540 * Refuse to truncate files with mandatory locks held on them.
1542 error
= locks_verify_locked(inode
);
1546 error
= do_truncate(dentry
, 0, ATTR_MTIME
|ATTR_CTIME
, NULL
);
1548 put_write_access(inode
);
1552 if (flag
& FMODE_WRITE
)
1561 * namei for open - this is in fact almost the whole open-routine.
1563 * Note that the low bits of "flag" aren't the same as in the open
1564 * system call - they are 00 - no permissions needed
1565 * 01 - read permission needed
1566 * 10 - write permission needed
1567 * 11 - read/write permissions needed
1568 * which is a lot more logical, and also allows the "no perm" needed
1569 * for symlinks (where the permissions are checked later).
1572 int open_namei(int dfd
, const char *pathname
, int flag
,
1573 int mode
, struct nameidata
*nd
)
1575 int acc_mode
, error
;
1580 acc_mode
= ACC_MODE(flag
);
1582 /* O_TRUNC implies we need access checks for write permissions */
1584 acc_mode
|= MAY_WRITE
;
1586 /* Allow the LSM permission hook to distinguish append
1587 access from general write access. */
1588 if (flag
& O_APPEND
)
1589 acc_mode
|= MAY_APPEND
;
1592 * The simplest case - just a plain lookup.
1594 if (!(flag
& O_CREAT
)) {
1595 error
= path_lookup_open(dfd
, pathname
, lookup_flags(flag
),
1603 * Create - we need to know the parent.
1605 error
= path_lookup_create(dfd
,pathname
,LOOKUP_PARENT
,nd
,flag
,mode
);
1610 * We have the parent and last component. First of all, check
1611 * that we are not asked to creat(2) an obvious directory - that
1615 if (nd
->last_type
!= LAST_NORM
|| nd
->last
.name
[nd
->last
.len
])
1619 nd
->flags
&= ~LOOKUP_PARENT
;
1620 mutex_lock(&dir
->d_inode
->i_mutex
);
1621 path
.dentry
= lookup_hash(nd
);
1625 error
= PTR_ERR(path
.dentry
);
1626 if (IS_ERR(path
.dentry
)) {
1627 mutex_unlock(&dir
->d_inode
->i_mutex
);
1631 if (IS_ERR(nd
->intent
.open
.file
)) {
1632 mutex_unlock(&dir
->d_inode
->i_mutex
);
1633 error
= PTR_ERR(nd
->intent
.open
.file
);
1637 /* Negative dentry, just create the file */
1638 if (!path
.dentry
->d_inode
) {
1639 if (!IS_POSIXACL(dir
->d_inode
))
1640 mode
&= ~current
->fs
->umask
;
1641 error
= vfs_create(dir
->d_inode
, path
.dentry
, mode
, nd
);
1642 mutex_unlock(&dir
->d_inode
->i_mutex
);
1644 nd
->dentry
= path
.dentry
;
1647 /* Don't check for write permission, don't truncate */
1654 * It already exists.
1656 mutex_unlock(&dir
->d_inode
->i_mutex
);
1662 if (__follow_mount(&path
)) {
1664 if (flag
& O_NOFOLLOW
)
1668 if (!path
.dentry
->d_inode
)
1670 if (path
.dentry
->d_inode
->i_op
&& path
.dentry
->d_inode
->i_op
->follow_link
)
1673 path_to_nameidata(&path
, nd
);
1675 if (path
.dentry
->d_inode
&& S_ISDIR(path
.dentry
->d_inode
->i_mode
))
1678 error
= may_open(nd
, acc_mode
, flag
);
1684 dput_path(&path
, nd
);
1686 if (!IS_ERR(nd
->intent
.open
.file
))
1687 release_open_intent(nd
);
1693 if (flag
& O_NOFOLLOW
)
1696 * This is subtle. Instead of calling do_follow_link() we do the
1697 * thing by hands. The reason is that this way we have zero link_count
1698 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1699 * After that we have the parent and last component, i.e.
1700 * we are in the same situation as after the first path_walk().
1701 * Well, almost - if the last component is normal we get its copy
1702 * stored in nd->last.name and we will have to putname() it when we
1703 * are done. Procfs-like symlinks just set LAST_BIND.
1705 nd
->flags
|= LOOKUP_PARENT
;
1706 error
= security_inode_follow_link(path
.dentry
, nd
);
1709 error
= __do_follow_link(&path
, nd
);
1712 nd
->flags
&= ~LOOKUP_PARENT
;
1713 if (nd
->last_type
== LAST_BIND
)
1716 if (nd
->last_type
!= LAST_NORM
)
1718 if (nd
->last
.name
[nd
->last
.len
]) {
1719 __putname(nd
->last
.name
);
1724 __putname(nd
->last
.name
);
1728 mutex_lock(&dir
->d_inode
->i_mutex
);
1729 path
.dentry
= lookup_hash(nd
);
1731 __putname(nd
->last
.name
);
1736 * lookup_create - lookup a dentry, creating it if it doesn't exist
1737 * @nd: nameidata info
1738 * @is_dir: directory flag
1740 * Simple function to lookup and return a dentry and create it
1741 * if it doesn't exist. Is SMP-safe.
1743 * Returns with nd->dentry->d_inode->i_mutex locked.
1745 struct dentry
*lookup_create(struct nameidata
*nd
, int is_dir
)
1747 struct dentry
*dentry
= ERR_PTR(-EEXIST
);
1749 mutex_lock(&nd
->dentry
->d_inode
->i_mutex
);
1751 * Yucky last component or no last component at all?
1752 * (foo/., foo/.., /////)
1754 if (nd
->last_type
!= LAST_NORM
)
1756 nd
->flags
&= ~LOOKUP_PARENT
;
1759 * Do the final lookup.
1761 dentry
= lookup_hash(nd
);
1766 * Special case - lookup gave negative, but... we had foo/bar/
1767 * From the vfs_mknod() POV we just have a negative dentry -
1768 * all is fine. Let's be bastards - you had / on the end, you've
1769 * been asking for (non-existent) directory. -ENOENT for you.
1771 if (!is_dir
&& nd
->last
.name
[nd
->last
.len
] && !dentry
->d_inode
)
1776 dentry
= ERR_PTR(-ENOENT
);
1780 EXPORT_SYMBOL_GPL(lookup_create
);
1782 int vfs_mknod(struct inode
*dir
, struct dentry
*dentry
, int mode
, dev_t dev
)
1784 int error
= may_create(dir
, dentry
, NULL
);
1789 if ((S_ISCHR(mode
) || S_ISBLK(mode
)) && !capable(CAP_MKNOD
))
1792 if (!dir
->i_op
|| !dir
->i_op
->mknod
)
1795 error
= security_inode_mknod(dir
, dentry
, mode
, dev
);
1800 error
= dir
->i_op
->mknod(dir
, dentry
, mode
, dev
);
1802 fsnotify_create(dir
, dentry
->d_name
.name
);
1806 asmlinkage
long sys_mknodat(int dfd
, const char __user
*filename
, int mode
,
1811 struct dentry
* dentry
;
1812 struct nameidata nd
;
1816 tmp
= getname(filename
);
1818 return PTR_ERR(tmp
);
1820 error
= do_path_lookup(dfd
, tmp
, LOOKUP_PARENT
, &nd
);
1823 dentry
= lookup_create(&nd
, 0);
1824 error
= PTR_ERR(dentry
);
1826 if (!IS_POSIXACL(nd
.dentry
->d_inode
))
1827 mode
&= ~current
->fs
->umask
;
1828 if (!IS_ERR(dentry
)) {
1829 switch (mode
& S_IFMT
) {
1830 case 0: case S_IFREG
:
1831 error
= vfs_create(nd
.dentry
->d_inode
,dentry
,mode
,&nd
);
1833 case S_IFCHR
: case S_IFBLK
:
1834 error
= vfs_mknod(nd
.dentry
->d_inode
,dentry
,mode
,
1835 new_decode_dev(dev
));
1837 case S_IFIFO
: case S_IFSOCK
:
1838 error
= vfs_mknod(nd
.dentry
->d_inode
,dentry
,mode
,0);
1848 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
1856 asmlinkage
long sys_mknod(const char __user
*filename
, int mode
, unsigned dev
)
1858 return sys_mknodat(AT_FDCWD
, filename
, mode
, dev
);
1861 int vfs_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
1863 int error
= may_create(dir
, dentry
, NULL
);
1868 if (!dir
->i_op
|| !dir
->i_op
->mkdir
)
1871 mode
&= (S_IRWXUGO
|S_ISVTX
);
1872 error
= security_inode_mkdir(dir
, dentry
, mode
);
1877 error
= dir
->i_op
->mkdir(dir
, dentry
, mode
);
1879 fsnotify_mkdir(dir
, dentry
->d_name
.name
);
1883 asmlinkage
long sys_mkdirat(int dfd
, const char __user
*pathname
, int mode
)
1888 tmp
= getname(pathname
);
1889 error
= PTR_ERR(tmp
);
1891 struct dentry
*dentry
;
1892 struct nameidata nd
;
1894 error
= do_path_lookup(dfd
, tmp
, LOOKUP_PARENT
, &nd
);
1897 dentry
= lookup_create(&nd
, 1);
1898 error
= PTR_ERR(dentry
);
1899 if (!IS_ERR(dentry
)) {
1900 if (!IS_POSIXACL(nd
.dentry
->d_inode
))
1901 mode
&= ~current
->fs
->umask
;
1902 error
= vfs_mkdir(nd
.dentry
->d_inode
, dentry
, mode
);
1905 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
1914 asmlinkage
long sys_mkdir(const char __user
*pathname
, int mode
)
1916 return sys_mkdirat(AT_FDCWD
, pathname
, mode
);
1920 * We try to drop the dentry early: we should have
1921 * a usage count of 2 if we're the only user of this
1922 * dentry, and if that is true (possibly after pruning
1923 * the dcache), then we drop the dentry now.
1925 * A low-level filesystem can, if it choses, legally
1928 * if (!d_unhashed(dentry))
1931 * if it cannot handle the case of removing a directory
1932 * that is still in use by something else..
1934 void dentry_unhash(struct dentry
*dentry
)
1937 if (atomic_read(&dentry
->d_count
))
1938 shrink_dcache_parent(dentry
);
1939 spin_lock(&dcache_lock
);
1940 spin_lock(&dentry
->d_lock
);
1941 if (atomic_read(&dentry
->d_count
) == 2)
1943 spin_unlock(&dentry
->d_lock
);
1944 spin_unlock(&dcache_lock
);
1947 int vfs_rmdir(struct inode
*dir
, struct dentry
*dentry
)
1949 int error
= may_delete(dir
, dentry
, 1);
1954 if (!dir
->i_op
|| !dir
->i_op
->rmdir
)
1959 mutex_lock(&dentry
->d_inode
->i_mutex
);
1960 dentry_unhash(dentry
);
1961 if (d_mountpoint(dentry
))
1964 error
= security_inode_rmdir(dir
, dentry
);
1966 error
= dir
->i_op
->rmdir(dir
, dentry
);
1968 dentry
->d_inode
->i_flags
|= S_DEAD
;
1971 mutex_unlock(&dentry
->d_inode
->i_mutex
);
1980 static long do_rmdir(int dfd
, const char __user
*pathname
)
1984 struct dentry
*dentry
;
1985 struct nameidata nd
;
1987 name
= getname(pathname
);
1989 return PTR_ERR(name
);
1991 error
= do_path_lookup(dfd
, name
, LOOKUP_PARENT
, &nd
);
1995 switch(nd
.last_type
) {
2006 mutex_lock(&nd
.dentry
->d_inode
->i_mutex
);
2007 dentry
= lookup_hash(&nd
);
2008 error
= PTR_ERR(dentry
);
2009 if (!IS_ERR(dentry
)) {
2010 error
= vfs_rmdir(nd
.dentry
->d_inode
, dentry
);
2013 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2021 asmlinkage
long sys_rmdir(const char __user
*pathname
)
2023 return do_rmdir(AT_FDCWD
, pathname
);
2026 int vfs_unlink(struct inode
*dir
, struct dentry
*dentry
)
2028 int error
= may_delete(dir
, dentry
, 0);
2033 if (!dir
->i_op
|| !dir
->i_op
->unlink
)
2038 mutex_lock(&dentry
->d_inode
->i_mutex
);
2039 if (d_mountpoint(dentry
))
2042 error
= security_inode_unlink(dir
, dentry
);
2044 error
= dir
->i_op
->unlink(dir
, dentry
);
2046 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2048 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2049 if (!error
&& !(dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)) {
2057 * Make sure that the actual truncation of the file will occur outside its
2058 * directory's i_mutex. Truncate can take a long time if there is a lot of
2059 * writeout happening, and we don't want to prevent access to the directory
2060 * while waiting on the I/O.
2062 static long do_unlinkat(int dfd
, const char __user
*pathname
)
2066 struct dentry
*dentry
;
2067 struct nameidata nd
;
2068 struct inode
*inode
= NULL
;
2070 name
= getname(pathname
);
2072 return PTR_ERR(name
);
2074 error
= do_path_lookup(dfd
, name
, LOOKUP_PARENT
, &nd
);
2078 if (nd
.last_type
!= LAST_NORM
)
2080 mutex_lock(&nd
.dentry
->d_inode
->i_mutex
);
2081 dentry
= lookup_hash(&nd
);
2082 error
= PTR_ERR(dentry
);
2083 if (!IS_ERR(dentry
)) {
2084 /* Why not before? Because we want correct error value */
2085 if (nd
.last
.name
[nd
.last
.len
])
2087 inode
= dentry
->d_inode
;
2089 atomic_inc(&inode
->i_count
);
2090 error
= vfs_unlink(nd
.dentry
->d_inode
, dentry
);
2094 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2096 iput(inode
); /* truncate the inode here */
2104 error
= !dentry
->d_inode
? -ENOENT
:
2105 S_ISDIR(dentry
->d_inode
->i_mode
) ? -EISDIR
: -ENOTDIR
;
2109 asmlinkage
long sys_unlinkat(int dfd
, const char __user
*pathname
, int flag
)
2111 if ((flag
& ~AT_REMOVEDIR
) != 0)
2114 if (flag
& AT_REMOVEDIR
)
2115 return do_rmdir(dfd
, pathname
);
2117 return do_unlinkat(dfd
, pathname
);
2120 asmlinkage
long sys_unlink(const char __user
*pathname
)
2122 return do_unlinkat(AT_FDCWD
, pathname
);
2125 int vfs_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *oldname
, int mode
)
2127 int error
= may_create(dir
, dentry
, NULL
);
2132 if (!dir
->i_op
|| !dir
->i_op
->symlink
)
2135 error
= security_inode_symlink(dir
, dentry
, oldname
);
2140 error
= dir
->i_op
->symlink(dir
, dentry
, oldname
);
2142 fsnotify_create(dir
, dentry
->d_name
.name
);
2146 asmlinkage
long sys_symlinkat(const char __user
*oldname
,
2147 int newdfd
, const char __user
*newname
)
2153 from
= getname(oldname
);
2155 return PTR_ERR(from
);
2156 to
= getname(newname
);
2157 error
= PTR_ERR(to
);
2159 struct dentry
*dentry
;
2160 struct nameidata nd
;
2162 error
= do_path_lookup(newdfd
, to
, LOOKUP_PARENT
, &nd
);
2165 dentry
= lookup_create(&nd
, 0);
2166 error
= PTR_ERR(dentry
);
2167 if (!IS_ERR(dentry
)) {
2168 error
= vfs_symlink(nd
.dentry
->d_inode
, dentry
, from
, S_IALLUGO
);
2171 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2180 asmlinkage
long sys_symlink(const char __user
*oldname
, const char __user
*newname
)
2182 return sys_symlinkat(oldname
, AT_FDCWD
, newname
);
2185 int vfs_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*new_dentry
)
2187 struct inode
*inode
= old_dentry
->d_inode
;
2193 error
= may_create(dir
, new_dentry
, NULL
);
2197 if (dir
->i_sb
!= inode
->i_sb
)
2201 * A link to an append-only or immutable file cannot be created.
2203 if (IS_APPEND(inode
) || IS_IMMUTABLE(inode
))
2205 if (!dir
->i_op
|| !dir
->i_op
->link
)
2207 if (S_ISDIR(old_dentry
->d_inode
->i_mode
))
2210 error
= security_inode_link(old_dentry
, dir
, new_dentry
);
2214 mutex_lock(&old_dentry
->d_inode
->i_mutex
);
2216 error
= dir
->i_op
->link(old_dentry
, dir
, new_dentry
);
2217 mutex_unlock(&old_dentry
->d_inode
->i_mutex
);
2219 fsnotify_create(dir
, new_dentry
->d_name
.name
);
2224 * Hardlinks are often used in delicate situations. We avoid
2225 * security-related surprises by not following symlinks on the
2228 * We don't follow them on the oldname either to be compatible
2229 * with linux 2.0, and to avoid hard-linking to directories
2230 * and other special files. --ADM
2232 asmlinkage
long sys_linkat(int olddfd
, const char __user
*oldname
,
2233 int newdfd
, const char __user
*newname
,
2236 struct dentry
*new_dentry
;
2237 struct nameidata nd
, old_nd
;
2244 to
= getname(newname
);
2248 error
= __user_walk_fd(olddfd
, oldname
, 0, &old_nd
);
2251 error
= do_path_lookup(newdfd
, to
, LOOKUP_PARENT
, &nd
);
2255 if (old_nd
.mnt
!= nd
.mnt
)
2257 new_dentry
= lookup_create(&nd
, 0);
2258 error
= PTR_ERR(new_dentry
);
2259 if (!IS_ERR(new_dentry
)) {
2260 error
= vfs_link(old_nd
.dentry
, nd
.dentry
->d_inode
, new_dentry
);
2263 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2267 path_release(&old_nd
);
2274 asmlinkage
long sys_link(const char __user
*oldname
, const char __user
*newname
)
2276 return sys_linkat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
, 0);
2280 * The worst of all namespace operations - renaming directory. "Perverted"
2281 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2283 * a) we can get into loop creation. Check is done in is_subdir().
2284 * b) race potential - two innocent renames can create a loop together.
2285 * That's where 4.4 screws up. Current fix: serialization on
2286 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
2288 * c) we have to lock _three_ objects - parents and victim (if it exists).
2289 * And that - after we got ->i_mutex on parents (until then we don't know
2290 * whether the target exists). Solution: try to be smart with locking
2291 * order for inodes. We rely on the fact that tree topology may change
2292 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
2293 * move will be locked. Thus we can rank directories by the tree
2294 * (ancestors first) and rank all non-directories after them.
2295 * That works since everybody except rename does "lock parent, lookup,
2296 * lock child" and rename is under ->s_vfs_rename_mutex.
2297 * HOWEVER, it relies on the assumption that any object with ->lookup()
2298 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2299 * we'd better make sure that there's no link(2) for them.
2300 * d) some filesystems don't support opened-but-unlinked directories,
2301 * either because of layout or because they are not ready to deal with
2302 * all cases correctly. The latter will be fixed (taking this sort of
2303 * stuff into VFS), but the former is not going away. Solution: the same
2304 * trick as in rmdir().
2305 * e) conversion from fhandle to dentry may come in the wrong moment - when
2306 * we are removing the target. Solution: we will have to grab ->i_mutex
2307 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
2308 * ->i_mutex on parents, which works but leads to some truely excessive
2311 static int vfs_rename_dir(struct inode
*old_dir
, struct dentry
*old_dentry
,
2312 struct inode
*new_dir
, struct dentry
*new_dentry
)
2315 struct inode
*target
;
2318 * If we are going to change the parent - check write permissions,
2319 * we'll need to flip '..'.
2321 if (new_dir
!= old_dir
) {
2322 error
= permission(old_dentry
->d_inode
, MAY_WRITE
, NULL
);
2327 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2331 target
= new_dentry
->d_inode
;
2333 mutex_lock(&target
->i_mutex
);
2334 dentry_unhash(new_dentry
);
2336 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2339 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2342 target
->i_flags
|= S_DEAD
;
2343 mutex_unlock(&target
->i_mutex
);
2344 if (d_unhashed(new_dentry
))
2345 d_rehash(new_dentry
);
2349 d_move(old_dentry
,new_dentry
);
2353 static int vfs_rename_other(struct inode
*old_dir
, struct dentry
*old_dentry
,
2354 struct inode
*new_dir
, struct dentry
*new_dentry
)
2356 struct inode
*target
;
2359 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2364 target
= new_dentry
->d_inode
;
2366 mutex_lock(&target
->i_mutex
);
2367 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2370 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2372 /* The following d_move() should become unconditional */
2373 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_ODD_RENAME
))
2374 d_move(old_dentry
, new_dentry
);
2377 mutex_unlock(&target
->i_mutex
);
2382 int vfs_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
2383 struct inode
*new_dir
, struct dentry
*new_dentry
)
2386 int is_dir
= S_ISDIR(old_dentry
->d_inode
->i_mode
);
2387 const char *old_name
;
2389 if (old_dentry
->d_inode
== new_dentry
->d_inode
)
2392 error
= may_delete(old_dir
, old_dentry
, is_dir
);
2396 if (!new_dentry
->d_inode
)
2397 error
= may_create(new_dir
, new_dentry
, NULL
);
2399 error
= may_delete(new_dir
, new_dentry
, is_dir
);
2403 if (!old_dir
->i_op
|| !old_dir
->i_op
->rename
)
2406 DQUOT_INIT(old_dir
);
2407 DQUOT_INIT(new_dir
);
2409 old_name
= fsnotify_oldname_init(old_dentry
->d_name
.name
);
2412 error
= vfs_rename_dir(old_dir
,old_dentry
,new_dir
,new_dentry
);
2414 error
= vfs_rename_other(old_dir
,old_dentry
,new_dir
,new_dentry
);
2416 const char *new_name
= old_dentry
->d_name
.name
;
2417 fsnotify_move(old_dir
, new_dir
, old_name
, new_name
, is_dir
,
2418 new_dentry
->d_inode
, old_dentry
->d_inode
);
2420 fsnotify_oldname_free(old_name
);
2425 static int do_rename(int olddfd
, const char *oldname
,
2426 int newdfd
, const char *newname
)
2429 struct dentry
* old_dir
, * new_dir
;
2430 struct dentry
* old_dentry
, *new_dentry
;
2431 struct dentry
* trap
;
2432 struct nameidata oldnd
, newnd
;
2434 error
= do_path_lookup(olddfd
, oldname
, LOOKUP_PARENT
, &oldnd
);
2438 error
= do_path_lookup(newdfd
, newname
, LOOKUP_PARENT
, &newnd
);
2443 if (oldnd
.mnt
!= newnd
.mnt
)
2446 old_dir
= oldnd
.dentry
;
2448 if (oldnd
.last_type
!= LAST_NORM
)
2451 new_dir
= newnd
.dentry
;
2452 if (newnd
.last_type
!= LAST_NORM
)
2455 trap
= lock_rename(new_dir
, old_dir
);
2457 old_dentry
= lookup_hash(&oldnd
);
2458 error
= PTR_ERR(old_dentry
);
2459 if (IS_ERR(old_dentry
))
2461 /* source must exist */
2463 if (!old_dentry
->d_inode
)
2465 /* unless the source is a directory trailing slashes give -ENOTDIR */
2466 if (!S_ISDIR(old_dentry
->d_inode
->i_mode
)) {
2468 if (oldnd
.last
.name
[oldnd
.last
.len
])
2470 if (newnd
.last
.name
[newnd
.last
.len
])
2473 /* source should not be ancestor of target */
2475 if (old_dentry
== trap
)
2477 new_dentry
= lookup_hash(&newnd
);
2478 error
= PTR_ERR(new_dentry
);
2479 if (IS_ERR(new_dentry
))
2481 /* target should not be an ancestor of source */
2483 if (new_dentry
== trap
)
2486 error
= vfs_rename(old_dir
->d_inode
, old_dentry
,
2487 new_dir
->d_inode
, new_dentry
);
2493 unlock_rename(new_dir
, old_dir
);
2495 path_release(&newnd
);
2497 path_release(&oldnd
);
2502 asmlinkage
long sys_renameat(int olddfd
, const char __user
*oldname
,
2503 int newdfd
, const char __user
*newname
)
2509 from
= getname(oldname
);
2511 return PTR_ERR(from
);
2512 to
= getname(newname
);
2513 error
= PTR_ERR(to
);
2515 error
= do_rename(olddfd
, from
, newdfd
, to
);
2522 asmlinkage
long sys_rename(const char __user
*oldname
, const char __user
*newname
)
2524 return sys_renameat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
);
2527 int vfs_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
, const char *link
)
2531 len
= PTR_ERR(link
);
2536 if (len
> (unsigned) buflen
)
2538 if (copy_to_user(buffer
, link
, len
))
2545 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2546 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2547 * using) it for any given inode is up to filesystem.
2549 int generic_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2551 struct nameidata nd
;
2555 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, &nd
);
2556 if (!IS_ERR(cookie
)) {
2557 int res
= vfs_readlink(dentry
, buffer
, buflen
, nd_get_link(&nd
));
2558 if (dentry
->d_inode
->i_op
->put_link
)
2559 dentry
->d_inode
->i_op
->put_link(dentry
, &nd
, cookie
);
2560 cookie
= ERR_PTR(res
);
2562 return PTR_ERR(cookie
);
2565 int vfs_follow_link(struct nameidata
*nd
, const char *link
)
2567 return __vfs_follow_link(nd
, link
);
2570 /* get the link contents into pagecache */
2571 static char *page_getlink(struct dentry
* dentry
, struct page
**ppage
)
2574 struct address_space
*mapping
= dentry
->d_inode
->i_mapping
;
2575 page
= read_cache_page(mapping
, 0, (filler_t
*)mapping
->a_ops
->readpage
,
2579 wait_on_page_locked(page
);
2580 if (!PageUptodate(page
))
2586 page_cache_release(page
);
2587 return ERR_PTR(-EIO
);
2593 int page_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2595 struct page
*page
= NULL
;
2596 char *s
= page_getlink(dentry
, &page
);
2597 int res
= vfs_readlink(dentry
,buffer
,buflen
,s
);
2600 page_cache_release(page
);
2605 void *page_follow_link_light(struct dentry
*dentry
, struct nameidata
*nd
)
2607 struct page
*page
= NULL
;
2608 nd_set_link(nd
, page_getlink(dentry
, &page
));
2612 void page_put_link(struct dentry
*dentry
, struct nameidata
*nd
, void *cookie
)
2614 struct page
*page
= cookie
;
2618 page_cache_release(page
);
2622 int __page_symlink(struct inode
*inode
, const char *symname
, int len
,
2625 struct address_space
*mapping
= inode
->i_mapping
;
2631 page
= find_or_create_page(mapping
, 0, gfp_mask
);
2634 err
= mapping
->a_ops
->prepare_write(NULL
, page
, 0, len
-1);
2635 if (err
== AOP_TRUNCATED_PAGE
) {
2636 page_cache_release(page
);
2641 kaddr
= kmap_atomic(page
, KM_USER0
);
2642 memcpy(kaddr
, symname
, len
-1);
2643 kunmap_atomic(kaddr
, KM_USER0
);
2644 err
= mapping
->a_ops
->commit_write(NULL
, page
, 0, len
-1);
2645 if (err
== AOP_TRUNCATED_PAGE
) {
2646 page_cache_release(page
);
2652 * Notice that we are _not_ going to block here - end of page is
2653 * unmapped, so this will only try to map the rest of page, see
2654 * that it is unmapped (typically even will not look into inode -
2655 * ->i_size will be enough for everything) and zero it out.
2656 * OTOH it's obviously correct and should make the page up-to-date.
2658 if (!PageUptodate(page
)) {
2659 err
= mapping
->a_ops
->readpage(NULL
, page
);
2660 if (err
!= AOP_TRUNCATED_PAGE
)
2661 wait_on_page_locked(page
);
2665 page_cache_release(page
);
2668 mark_inode_dirty(inode
);
2672 page_cache_release(page
);
2677 int page_symlink(struct inode
*inode
, const char *symname
, int len
)
2679 return __page_symlink(inode
, symname
, len
,
2680 mapping_gfp_mask(inode
->i_mapping
));
2683 struct inode_operations page_symlink_inode_operations
= {
2684 .readlink
= generic_readlink
,
2685 .follow_link
= page_follow_link_light
,
2686 .put_link
= page_put_link
,
2689 EXPORT_SYMBOL(__user_walk
);
2690 EXPORT_SYMBOL(__user_walk_fd
);
2691 EXPORT_SYMBOL(follow_down
);
2692 EXPORT_SYMBOL(follow_up
);
2693 EXPORT_SYMBOL(get_write_access
); /* binfmt_aout */
2694 EXPORT_SYMBOL(getname
);
2695 EXPORT_SYMBOL(lock_rename
);
2696 EXPORT_SYMBOL(lookup_hash
);
2697 EXPORT_SYMBOL(lookup_one_len
);
2698 EXPORT_SYMBOL(page_follow_link_light
);
2699 EXPORT_SYMBOL(page_put_link
);
2700 EXPORT_SYMBOL(page_readlink
);
2701 EXPORT_SYMBOL(__page_symlink
);
2702 EXPORT_SYMBOL(page_symlink
);
2703 EXPORT_SYMBOL(page_symlink_inode_operations
);
2704 EXPORT_SYMBOL(path_lookup
);
2705 EXPORT_SYMBOL(path_release
);
2706 EXPORT_SYMBOL(path_walk
);
2707 EXPORT_SYMBOL(permission
);
2708 EXPORT_SYMBOL(vfs_permission
);
2709 EXPORT_SYMBOL(file_permission
);
2710 EXPORT_SYMBOL(unlock_rename
);
2711 EXPORT_SYMBOL(vfs_create
);
2712 EXPORT_SYMBOL(vfs_follow_link
);
2713 EXPORT_SYMBOL(vfs_link
);
2714 EXPORT_SYMBOL(vfs_mkdir
);
2715 EXPORT_SYMBOL(vfs_mknod
);
2716 EXPORT_SYMBOL(generic_permission
);
2717 EXPORT_SYMBOL(vfs_readlink
);
2718 EXPORT_SYMBOL(vfs_rename
);
2719 EXPORT_SYMBOL(vfs_rmdir
);
2720 EXPORT_SYMBOL(vfs_symlink
);
2721 EXPORT_SYMBOL(vfs_unlink
);
2722 EXPORT_SYMBOL(dentry_unhash
);
2723 EXPORT_SYMBOL(generic_readlink
);