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(!audit_dummy_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
)
230 umode_t mode
= inode
->i_mode
;
233 if (mask
& MAY_WRITE
) {
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
))
251 * MAY_EXEC on regular files requires special handling: We override
252 * filesystem execute permissions if the mode bits aren't set or
253 * the fs is mounted with the "noexec" flag.
255 if ((mask
& MAY_EXEC
) && S_ISREG(mode
) && (!(mode
& S_IXUGO
) ||
256 (nd
&& nd
->mnt
&& (nd
->mnt
->mnt_flags
& MNT_NOEXEC
))))
259 /* Ordinary permission routines do not understand MAY_APPEND. */
260 submask
= mask
& ~MAY_APPEND
;
261 if (inode
->i_op
&& inode
->i_op
->permission
)
262 retval
= inode
->i_op
->permission(inode
, submask
, nd
);
264 retval
= generic_permission(inode
, submask
, NULL
);
268 return security_inode_permission(inode
, mask
, nd
);
272 * vfs_permission - check for access rights to a given path
273 * @nd: lookup result that describes the path
274 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
276 * Used to check for read/write/execute permissions on a path.
277 * We use "fsuid" for this, letting us set arbitrary permissions
278 * for filesystem access without changing the "normal" uids which
279 * are used for other things.
281 int vfs_permission(struct nameidata
*nd
, int mask
)
283 return permission(nd
->dentry
->d_inode
, mask
, nd
);
287 * file_permission - check for additional access rights to a given file
288 * @file: file to check access rights for
289 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
291 * Used to check for read/write/execute permissions on an already opened
295 * Do not use this function in new code. All access checks should
296 * be done using vfs_permission().
298 int file_permission(struct file
*file
, int mask
)
300 return permission(file
->f_path
.dentry
->d_inode
, mask
, NULL
);
304 * get_write_access() gets write permission for a file.
305 * put_write_access() releases this write permission.
306 * This is used for regular files.
307 * We cannot support write (and maybe mmap read-write shared) accesses and
308 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
309 * can have the following values:
310 * 0: no writers, no VM_DENYWRITE mappings
311 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
312 * > 0: (i_writecount) users are writing to the file.
314 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
315 * except for the cases where we don't hold i_writecount yet. Then we need to
316 * use {get,deny}_write_access() - these functions check the sign and refuse
317 * to do the change if sign is wrong. Exclusion between them is provided by
318 * the inode->i_lock spinlock.
321 int get_write_access(struct inode
* inode
)
323 spin_lock(&inode
->i_lock
);
324 if (atomic_read(&inode
->i_writecount
) < 0) {
325 spin_unlock(&inode
->i_lock
);
328 atomic_inc(&inode
->i_writecount
);
329 spin_unlock(&inode
->i_lock
);
334 int deny_write_access(struct file
* file
)
336 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
338 spin_lock(&inode
->i_lock
);
339 if (atomic_read(&inode
->i_writecount
) > 0) {
340 spin_unlock(&inode
->i_lock
);
343 atomic_dec(&inode
->i_writecount
);
344 spin_unlock(&inode
->i_lock
);
349 void path_release(struct nameidata
*nd
)
356 * umount() mustn't call path_release()/mntput() as that would clear
359 void path_release_on_umount(struct nameidata
*nd
)
362 mntput_no_expire(nd
->mnt
);
366 * release_open_intent - free up open intent resources
367 * @nd: pointer to nameidata
369 void release_open_intent(struct nameidata
*nd
)
371 if (nd
->intent
.open
.file
->f_path
.dentry
== NULL
)
372 put_filp(nd
->intent
.open
.file
);
374 fput(nd
->intent
.open
.file
);
377 static inline struct dentry
*
378 do_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
380 int status
= dentry
->d_op
->d_revalidate(dentry
, nd
);
381 if (unlikely(status
<= 0)) {
383 * The dentry failed validation.
384 * If d_revalidate returned 0 attempt to invalidate
385 * the dentry otherwise d_revalidate is asking us
386 * to return a fail status.
389 if (!d_invalidate(dentry
)) {
395 dentry
= ERR_PTR(status
);
402 * Internal lookup() using the new generic dcache.
405 static struct dentry
* cached_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
407 struct dentry
* dentry
= __d_lookup(parent
, name
);
409 /* lockess __d_lookup may fail due to concurrent d_move()
410 * in some unrelated directory, so try with d_lookup
413 dentry
= d_lookup(parent
, name
);
415 if (dentry
&& dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
416 dentry
= do_revalidate(dentry
, nd
);
422 * Short-cut version of permission(), for calling by
423 * path_walk(), when dcache lock is held. Combines parts
424 * of permission() and generic_permission(), and tests ONLY for
425 * MAY_EXEC permission.
427 * If appropriate, check DAC only. If not appropriate, or
428 * short-cut DAC fails, then call permission() to do more
429 * complete permission check.
431 static int exec_permission_lite(struct inode
*inode
,
432 struct nameidata
*nd
)
434 umode_t mode
= inode
->i_mode
;
436 if (inode
->i_op
&& inode
->i_op
->permission
)
439 if (current
->fsuid
== inode
->i_uid
)
441 else if (in_group_p(inode
->i_gid
))
447 if ((inode
->i_mode
& S_IXUGO
) && capable(CAP_DAC_OVERRIDE
))
450 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_OVERRIDE
))
453 if (S_ISDIR(inode
->i_mode
) && capable(CAP_DAC_READ_SEARCH
))
458 return security_inode_permission(inode
, MAY_EXEC
, nd
);
462 * This is called when everything else fails, and we actually have
463 * to go to the low-level filesystem to find out what we should do..
465 * We get the directory semaphore, and after getting that we also
466 * make sure that nobody added the entry to the dcache in the meantime..
469 static struct dentry
* real_lookup(struct dentry
* parent
, struct qstr
* name
, struct nameidata
*nd
)
471 struct dentry
* result
;
472 struct inode
*dir
= parent
->d_inode
;
474 mutex_lock(&dir
->i_mutex
);
476 * First re-do the cached lookup just in case it was created
477 * while we waited for the directory semaphore..
479 * FIXME! This could use version numbering or similar to
480 * avoid unnecessary cache lookups.
482 * The "dcache_lock" is purely to protect the RCU list walker
483 * from concurrent renames at this point (we mustn't get false
484 * negatives from the RCU list walk here, unlike the optimistic
487 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
489 result
= d_lookup(parent
, name
);
491 struct dentry
* dentry
= d_alloc(parent
, name
);
492 result
= ERR_PTR(-ENOMEM
);
494 result
= dir
->i_op
->lookup(dir
, dentry
, nd
);
500 mutex_unlock(&dir
->i_mutex
);
505 * Uhhuh! Nasty case: the cache was re-populated while
506 * we waited on the semaphore. Need to revalidate.
508 mutex_unlock(&dir
->i_mutex
);
509 if (result
->d_op
&& result
->d_op
->d_revalidate
) {
510 result
= do_revalidate(result
, nd
);
512 result
= ERR_PTR(-ENOENT
);
517 static int __emul_lookup_dentry(const char *, struct nameidata
*);
520 static __always_inline
int
521 walk_init_root(const char *name
, struct nameidata
*nd
)
523 struct fs_struct
*fs
= current
->fs
;
525 read_lock(&fs
->lock
);
526 if (fs
->altroot
&& !(nd
->flags
& LOOKUP_NOALT
)) {
527 nd
->mnt
= mntget(fs
->altrootmnt
);
528 nd
->dentry
= dget(fs
->altroot
);
529 read_unlock(&fs
->lock
);
530 if (__emul_lookup_dentry(name
,nd
))
532 read_lock(&fs
->lock
);
534 nd
->mnt
= mntget(fs
->rootmnt
);
535 nd
->dentry
= dget(fs
->root
);
536 read_unlock(&fs
->lock
);
540 static __always_inline
int __vfs_follow_link(struct nameidata
*nd
, const char *link
)
549 if (!walk_init_root(link
, nd
))
550 /* weird __emul_prefix() stuff did it */
553 res
= link_path_walk(link
, nd
);
555 if (nd
->depth
|| res
|| nd
->last_type
!=LAST_NORM
)
558 * If it is an iterative symlinks resolution in open_namei() we
559 * have to copy the last component. And all that crap because of
560 * bloody create() on broken symlinks. Furrfu...
563 if (unlikely(!name
)) {
567 strcpy(name
, nd
->last
.name
);
568 nd
->last
.name
= name
;
572 return PTR_ERR(link
);
575 static inline void dput_path(struct path
*path
, struct nameidata
*nd
)
578 if (path
->mnt
!= nd
->mnt
)
582 static inline void path_to_nameidata(struct path
*path
, struct nameidata
*nd
)
585 if (nd
->mnt
!= path
->mnt
)
588 nd
->dentry
= path
->dentry
;
591 static __always_inline
int __do_follow_link(struct path
*path
, struct nameidata
*nd
)
595 struct dentry
*dentry
= path
->dentry
;
597 touch_atime(path
->mnt
, dentry
);
598 nd_set_link(nd
, NULL
);
600 if (path
->mnt
!= nd
->mnt
) {
601 path_to_nameidata(path
, nd
);
605 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, nd
);
606 error
= PTR_ERR(cookie
);
607 if (!IS_ERR(cookie
)) {
608 char *s
= nd_get_link(nd
);
611 error
= __vfs_follow_link(nd
, s
);
612 if (dentry
->d_inode
->i_op
->put_link
)
613 dentry
->d_inode
->i_op
->put_link(dentry
, nd
, cookie
);
622 * This limits recursive symlink follows to 8, while
623 * limiting consecutive symlinks to 40.
625 * Without that kind of total limit, nasty chains of consecutive
626 * symlinks can cause almost arbitrarily long lookups.
628 static inline int do_follow_link(struct path
*path
, struct nameidata
*nd
)
631 if (current
->link_count
>= MAX_NESTED_LINKS
)
633 if (current
->total_link_count
>= 40)
635 BUG_ON(nd
->depth
>= MAX_NESTED_LINKS
);
637 err
= security_inode_follow_link(path
->dentry
, nd
);
640 current
->link_count
++;
641 current
->total_link_count
++;
643 err
= __do_follow_link(path
, nd
);
644 current
->link_count
--;
653 int follow_up(struct vfsmount
**mnt
, struct dentry
**dentry
)
655 struct vfsmount
*parent
;
656 struct dentry
*mountpoint
;
657 spin_lock(&vfsmount_lock
);
658 parent
=(*mnt
)->mnt_parent
;
659 if (parent
== *mnt
) {
660 spin_unlock(&vfsmount_lock
);
664 mountpoint
=dget((*mnt
)->mnt_mountpoint
);
665 spin_unlock(&vfsmount_lock
);
667 *dentry
= mountpoint
;
673 /* no need for dcache_lock, as serialization is taken care in
676 static int __follow_mount(struct path
*path
)
679 while (d_mountpoint(path
->dentry
)) {
680 struct vfsmount
*mounted
= lookup_mnt(path
->mnt
, path
->dentry
);
687 path
->dentry
= dget(mounted
->mnt_root
);
693 static void follow_mount(struct vfsmount
**mnt
, struct dentry
**dentry
)
695 while (d_mountpoint(*dentry
)) {
696 struct vfsmount
*mounted
= lookup_mnt(*mnt
, *dentry
);
702 *dentry
= dget(mounted
->mnt_root
);
706 /* no need for dcache_lock, as serialization is taken care in
709 int follow_down(struct vfsmount
**mnt
, struct dentry
**dentry
)
711 struct vfsmount
*mounted
;
713 mounted
= lookup_mnt(*mnt
, *dentry
);
718 *dentry
= dget(mounted
->mnt_root
);
724 static __always_inline
void follow_dotdot(struct nameidata
*nd
)
726 struct fs_struct
*fs
= current
->fs
;
729 struct vfsmount
*parent
;
730 struct dentry
*old
= nd
->dentry
;
732 read_lock(&fs
->lock
);
733 if (nd
->dentry
== fs
->root
&&
734 nd
->mnt
== fs
->rootmnt
) {
735 read_unlock(&fs
->lock
);
738 read_unlock(&fs
->lock
);
739 spin_lock(&dcache_lock
);
740 if (nd
->dentry
!= nd
->mnt
->mnt_root
) {
741 nd
->dentry
= dget(nd
->dentry
->d_parent
);
742 spin_unlock(&dcache_lock
);
746 spin_unlock(&dcache_lock
);
747 spin_lock(&vfsmount_lock
);
748 parent
= nd
->mnt
->mnt_parent
;
749 if (parent
== nd
->mnt
) {
750 spin_unlock(&vfsmount_lock
);
754 nd
->dentry
= dget(nd
->mnt
->mnt_mountpoint
);
755 spin_unlock(&vfsmount_lock
);
760 follow_mount(&nd
->mnt
, &nd
->dentry
);
764 * It's more convoluted than I'd like it to be, but... it's still fairly
765 * small and for now I'd prefer to have fast path as straight as possible.
766 * It _is_ time-critical.
768 static int do_lookup(struct nameidata
*nd
, struct qstr
*name
,
771 struct vfsmount
*mnt
= nd
->mnt
;
772 struct dentry
*dentry
= __d_lookup(nd
->dentry
, name
);
776 if (dentry
->d_op
&& dentry
->d_op
->d_revalidate
)
777 goto need_revalidate
;
780 path
->dentry
= dentry
;
781 __follow_mount(path
);
785 dentry
= real_lookup(nd
->dentry
, name
, nd
);
791 dentry
= do_revalidate(dentry
, nd
);
799 return PTR_ERR(dentry
);
804 * This is the basic name resolution function, turning a pathname into
805 * the final dentry. We expect 'base' to be positive and a directory.
807 * Returns 0 and nd will have valid dentry and mnt on success.
808 * Returns error and drops reference to input namei data on failure.
810 static fastcall
int __link_path_walk(const char * name
, struct nameidata
*nd
)
815 unsigned int lookup_flags
= nd
->flags
;
822 inode
= nd
->dentry
->d_inode
;
824 lookup_flags
= LOOKUP_FOLLOW
| (nd
->flags
& LOOKUP_CONTINUE
);
826 /* At this point we know we have a real path component. */
832 nd
->flags
|= LOOKUP_CONTINUE
;
833 err
= exec_permission_lite(inode
, nd
);
835 err
= vfs_permission(nd
, MAY_EXEC
);
840 c
= *(const unsigned char *)name
;
842 hash
= init_name_hash();
845 hash
= partial_name_hash(c
, hash
);
846 c
= *(const unsigned char *)name
;
847 } while (c
&& (c
!= '/'));
848 this.len
= name
- (const char *) this.name
;
849 this.hash
= end_name_hash(hash
);
851 /* remove trailing slashes? */
854 while (*++name
== '/');
856 goto last_with_slashes
;
859 * "." and ".." are special - ".." especially so because it has
860 * to be able to know about the current root directory and
861 * parent relationships.
863 if (this.name
[0] == '.') switch (this.len
) {
867 if (this.name
[1] != '.')
870 inode
= nd
->dentry
->d_inode
;
876 * See if the low-level filesystem might want
877 * to use its own hash..
879 if (nd
->dentry
->d_op
&& nd
->dentry
->d_op
->d_hash
) {
880 err
= nd
->dentry
->d_op
->d_hash(nd
->dentry
, &this);
884 /* This does the actual lookups.. */
885 err
= do_lookup(nd
, &this, &next
);
890 inode
= next
.dentry
->d_inode
;
897 if (inode
->i_op
->follow_link
) {
898 err
= do_follow_link(&next
, nd
);
902 inode
= nd
->dentry
->d_inode
;
909 path_to_nameidata(&next
, nd
);
911 if (!inode
->i_op
->lookup
)
914 /* here ends the main loop */
917 lookup_flags
|= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
919 /* Clear LOOKUP_CONTINUE iff it was previously unset */
920 nd
->flags
&= lookup_flags
| ~LOOKUP_CONTINUE
;
921 if (lookup_flags
& LOOKUP_PARENT
)
923 if (this.name
[0] == '.') switch (this.len
) {
927 if (this.name
[1] != '.')
930 inode
= nd
->dentry
->d_inode
;
935 if (nd
->dentry
->d_op
&& nd
->dentry
->d_op
->d_hash
) {
936 err
= nd
->dentry
->d_op
->d_hash(nd
->dentry
, &this);
940 err
= do_lookup(nd
, &this, &next
);
943 inode
= next
.dentry
->d_inode
;
944 if ((lookup_flags
& LOOKUP_FOLLOW
)
945 && inode
&& inode
->i_op
&& inode
->i_op
->follow_link
) {
946 err
= do_follow_link(&next
, nd
);
949 inode
= nd
->dentry
->d_inode
;
951 path_to_nameidata(&next
, nd
);
955 if (lookup_flags
& LOOKUP_DIRECTORY
) {
957 if (!inode
->i_op
|| !inode
->i_op
->lookup
)
963 nd
->last_type
= LAST_NORM
;
964 if (this.name
[0] != '.')
967 nd
->last_type
= LAST_DOT
;
968 else if (this.len
== 2 && this.name
[1] == '.')
969 nd
->last_type
= LAST_DOTDOT
;
974 * We bypassed the ordinary revalidation routines.
975 * We may need to check the cached dentry for staleness.
977 if (nd
->dentry
&& nd
->dentry
->d_sb
&&
978 (nd
->dentry
->d_sb
->s_type
->fs_flags
& FS_REVAL_DOT
)) {
980 /* Note: we do not d_invalidate() */
981 if (!nd
->dentry
->d_op
->d_revalidate(nd
->dentry
, nd
))
987 dput_path(&next
, nd
);
996 * Wrapper to retry pathname resolution whenever the underlying
997 * file system returns an ESTALE.
999 * Retry the whole path once, forcing real lookup requests
1000 * instead of relying on the dcache.
1002 int fastcall
link_path_walk(const char *name
, struct nameidata
*nd
)
1004 struct nameidata save
= *nd
;
1007 /* make sure the stuff we saved doesn't go away */
1011 result
= __link_path_walk(name
, nd
);
1012 if (result
== -ESTALE
) {
1016 nd
->flags
|= LOOKUP_REVAL
;
1017 result
= __link_path_walk(name
, nd
);
1026 int fastcall
path_walk(const char * name
, struct nameidata
*nd
)
1028 current
->total_link_count
= 0;
1029 return link_path_walk(name
, nd
);
1033 * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
1034 * everything is done. Returns 0 and drops input nd, if lookup failed;
1036 static int __emul_lookup_dentry(const char *name
, struct nameidata
*nd
)
1038 if (path_walk(name
, nd
))
1039 return 0; /* something went wrong... */
1041 if (!nd
->dentry
->d_inode
|| S_ISDIR(nd
->dentry
->d_inode
->i_mode
)) {
1042 struct dentry
*old_dentry
= nd
->dentry
;
1043 struct vfsmount
*old_mnt
= nd
->mnt
;
1044 struct qstr last
= nd
->last
;
1045 int last_type
= nd
->last_type
;
1046 struct fs_struct
*fs
= current
->fs
;
1049 * NAME was not found in alternate root or it's a directory.
1050 * Try to find it in the normal root:
1052 nd
->last_type
= LAST_ROOT
;
1053 read_lock(&fs
->lock
);
1054 nd
->mnt
= mntget(fs
->rootmnt
);
1055 nd
->dentry
= dget(fs
->root
);
1056 read_unlock(&fs
->lock
);
1057 if (path_walk(name
, nd
) == 0) {
1058 if (nd
->dentry
->d_inode
) {
1065 nd
->dentry
= old_dentry
;
1068 nd
->last_type
= last_type
;
1073 void set_fs_altroot(void)
1075 char *emul
= __emul_prefix();
1076 struct nameidata nd
;
1077 struct vfsmount
*mnt
= NULL
, *oldmnt
;
1078 struct dentry
*dentry
= NULL
, *olddentry
;
1080 struct fs_struct
*fs
= current
->fs
;
1084 err
= path_lookup(emul
, LOOKUP_FOLLOW
|LOOKUP_DIRECTORY
|LOOKUP_NOALT
, &nd
);
1090 write_lock(&fs
->lock
);
1091 oldmnt
= fs
->altrootmnt
;
1092 olddentry
= fs
->altroot
;
1093 fs
->altrootmnt
= mnt
;
1094 fs
->altroot
= dentry
;
1095 write_unlock(&fs
->lock
);
1102 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
1103 static int fastcall
do_path_lookup(int dfd
, const char *name
,
1104 unsigned int flags
, struct nameidata
*nd
)
1109 struct fs_struct
*fs
= current
->fs
;
1111 nd
->last_type
= LAST_ROOT
; /* if there are only slashes... */
1116 read_lock(&fs
->lock
);
1117 if (fs
->altroot
&& !(nd
->flags
& LOOKUP_NOALT
)) {
1118 nd
->mnt
= mntget(fs
->altrootmnt
);
1119 nd
->dentry
= dget(fs
->altroot
);
1120 read_unlock(&fs
->lock
);
1121 if (__emul_lookup_dentry(name
,nd
))
1122 goto out
; /* found in altroot */
1123 read_lock(&fs
->lock
);
1125 nd
->mnt
= mntget(fs
->rootmnt
);
1126 nd
->dentry
= dget(fs
->root
);
1127 read_unlock(&fs
->lock
);
1128 } else if (dfd
== AT_FDCWD
) {
1129 read_lock(&fs
->lock
);
1130 nd
->mnt
= mntget(fs
->pwdmnt
);
1131 nd
->dentry
= dget(fs
->pwd
);
1132 read_unlock(&fs
->lock
);
1134 struct dentry
*dentry
;
1136 file
= fget_light(dfd
, &fput_needed
);
1141 dentry
= file
->f_path
.dentry
;
1144 if (!S_ISDIR(dentry
->d_inode
->i_mode
))
1147 retval
= file_permission(file
, MAY_EXEC
);
1151 nd
->mnt
= mntget(file
->f_path
.mnt
);
1152 nd
->dentry
= dget(dentry
);
1154 fput_light(file
, fput_needed
);
1156 current
->total_link_count
= 0;
1157 retval
= link_path_walk(name
, nd
);
1159 if (likely(retval
== 0)) {
1160 if (unlikely(!audit_dummy_context() && nd
&& nd
->dentry
&&
1161 nd
->dentry
->d_inode
))
1162 audit_inode(name
, nd
->dentry
->d_inode
);
1168 fput_light(file
, fput_needed
);
1172 int fastcall
path_lookup(const char *name
, unsigned int flags
,
1173 struct nameidata
*nd
)
1175 return do_path_lookup(AT_FDCWD
, name
, flags
, nd
);
1178 static int __path_lookup_intent_open(int dfd
, const char *name
,
1179 unsigned int lookup_flags
, struct nameidata
*nd
,
1180 int open_flags
, int create_mode
)
1182 struct file
*filp
= get_empty_filp();
1187 nd
->intent
.open
.file
= filp
;
1188 nd
->intent
.open
.flags
= open_flags
;
1189 nd
->intent
.open
.create_mode
= create_mode
;
1190 err
= do_path_lookup(dfd
, name
, lookup_flags
|LOOKUP_OPEN
, nd
);
1191 if (IS_ERR(nd
->intent
.open
.file
)) {
1193 err
= PTR_ERR(nd
->intent
.open
.file
);
1196 } else if (err
!= 0)
1197 release_open_intent(nd
);
1202 * path_lookup_open - lookup a file path with open intent
1203 * @dfd: the directory to use as base, or AT_FDCWD
1204 * @name: pointer to file name
1205 * @lookup_flags: lookup intent flags
1206 * @nd: pointer to nameidata
1207 * @open_flags: open intent flags
1209 int path_lookup_open(int dfd
, const char *name
, unsigned int lookup_flags
,
1210 struct nameidata
*nd
, int open_flags
)
1212 return __path_lookup_intent_open(dfd
, name
, lookup_flags
, nd
,
1217 * path_lookup_create - lookup a file path with open + create intent
1218 * @dfd: the directory to use as base, or AT_FDCWD
1219 * @name: pointer to file name
1220 * @lookup_flags: lookup intent flags
1221 * @nd: pointer to nameidata
1222 * @open_flags: open intent flags
1223 * @create_mode: create intent flags
1225 static int path_lookup_create(int dfd
, const char *name
,
1226 unsigned int lookup_flags
, struct nameidata
*nd
,
1227 int open_flags
, int create_mode
)
1229 return __path_lookup_intent_open(dfd
, name
, lookup_flags
|LOOKUP_CREATE
,
1230 nd
, open_flags
, create_mode
);
1233 int __user_path_lookup_open(const char __user
*name
, unsigned int lookup_flags
,
1234 struct nameidata
*nd
, int open_flags
)
1236 char *tmp
= getname(name
);
1237 int err
= PTR_ERR(tmp
);
1240 err
= __path_lookup_intent_open(AT_FDCWD
, tmp
, lookup_flags
, nd
, open_flags
, 0);
1246 static inline struct dentry
*__lookup_hash_kern(struct qstr
*name
, struct dentry
*base
, struct nameidata
*nd
)
1248 struct dentry
*dentry
;
1249 struct inode
*inode
;
1252 inode
= base
->d_inode
;
1255 * See if the low-level filesystem might want
1256 * to use its own hash..
1258 if (base
->d_op
&& base
->d_op
->d_hash
) {
1259 err
= base
->d_op
->d_hash(base
, name
);
1260 dentry
= ERR_PTR(err
);
1265 dentry
= cached_lookup(base
, name
, nd
);
1267 struct dentry
*new = d_alloc(base
, name
);
1268 dentry
= ERR_PTR(-ENOMEM
);
1271 dentry
= inode
->i_op
->lookup(inode
, new, nd
);
1282 * Restricted form of lookup. Doesn't follow links, single-component only,
1283 * needs parent already locked. Doesn't follow mounts.
1286 static inline struct dentry
* __lookup_hash(struct qstr
*name
, struct dentry
*base
, struct nameidata
*nd
)
1288 struct dentry
*dentry
;
1289 struct inode
*inode
;
1292 inode
= base
->d_inode
;
1294 err
= permission(inode
, MAY_EXEC
, nd
);
1295 dentry
= ERR_PTR(err
);
1299 dentry
= __lookup_hash_kern(name
, base
, nd
);
1304 static struct dentry
*lookup_hash(struct nameidata
*nd
)
1306 return __lookup_hash(&nd
->last
, nd
->dentry
, nd
);
1310 static inline int __lookup_one_len(const char *name
, struct qstr
*this, struct dentry
*base
, int len
)
1320 hash
= init_name_hash();
1322 c
= *(const unsigned char *)name
++;
1323 if (c
== '/' || c
== '\0')
1325 hash
= partial_name_hash(c
, hash
);
1327 this->hash
= end_name_hash(hash
);
1331 struct dentry
*lookup_one_len(const char *name
, struct dentry
*base
, int len
)
1336 err
= __lookup_one_len(name
, &this, base
, len
);
1338 return ERR_PTR(err
);
1339 return __lookup_hash(&this, base
, NULL
);
1342 struct dentry
*lookup_one_len_kern(const char *name
, struct dentry
*base
, int len
)
1347 err
= __lookup_one_len(name
, &this, base
, len
);
1349 return ERR_PTR(err
);
1350 return __lookup_hash_kern(&this, base
, NULL
);
1353 int fastcall
__user_walk_fd(int dfd
, const char __user
*name
, unsigned flags
,
1354 struct nameidata
*nd
)
1356 char *tmp
= getname(name
);
1357 int err
= PTR_ERR(tmp
);
1360 err
= do_path_lookup(dfd
, tmp
, flags
, nd
);
1366 int fastcall
__user_walk(const char __user
*name
, unsigned flags
, struct nameidata
*nd
)
1368 return __user_walk_fd(AT_FDCWD
, name
, flags
, nd
);
1372 * It's inline, so penalty for filesystems that don't use sticky bit is
1375 static inline int check_sticky(struct inode
*dir
, struct inode
*inode
)
1377 if (!(dir
->i_mode
& S_ISVTX
))
1379 if (inode
->i_uid
== current
->fsuid
)
1381 if (dir
->i_uid
== current
->fsuid
)
1383 return !capable(CAP_FOWNER
);
1387 * Check whether we can remove a link victim from directory dir, check
1388 * whether the type of victim is right.
1389 * 1. We can't do it if dir is read-only (done in permission())
1390 * 2. We should have write and exec permissions on dir
1391 * 3. We can't remove anything from append-only dir
1392 * 4. We can't do anything with immutable dir (done in permission())
1393 * 5. If the sticky bit on dir is set we should either
1394 * a. be owner of dir, or
1395 * b. be owner of victim, or
1396 * c. have CAP_FOWNER capability
1397 * 6. If the victim is append-only or immutable we can't do antyhing with
1398 * links pointing to it.
1399 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1400 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1401 * 9. We can't remove a root or mountpoint.
1402 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1403 * nfs_async_unlink().
1405 static int may_delete(struct inode
*dir
,struct dentry
*victim
,int isdir
)
1409 if (!victim
->d_inode
)
1412 BUG_ON(victim
->d_parent
->d_inode
!= dir
);
1413 audit_inode_child(victim
->d_name
.name
, victim
->d_inode
, dir
);
1415 error
= permission(dir
,MAY_WRITE
| MAY_EXEC
, NULL
);
1420 if (check_sticky(dir
, victim
->d_inode
)||IS_APPEND(victim
->d_inode
)||
1421 IS_IMMUTABLE(victim
->d_inode
))
1424 if (!S_ISDIR(victim
->d_inode
->i_mode
))
1426 if (IS_ROOT(victim
))
1428 } else if (S_ISDIR(victim
->d_inode
->i_mode
))
1430 if (IS_DEADDIR(dir
))
1432 if (victim
->d_flags
& DCACHE_NFSFS_RENAMED
)
1437 /* Check whether we can create an object with dentry child in directory
1439 * 1. We can't do it if child already exists (open has special treatment for
1440 * this case, but since we are inlined it's OK)
1441 * 2. We can't do it if dir is read-only (done in permission())
1442 * 3. We should have write and exec permissions on dir
1443 * 4. We can't do it if dir is immutable (done in permission())
1445 static inline int may_create(struct inode
*dir
, struct dentry
*child
,
1446 struct nameidata
*nd
)
1450 if (IS_DEADDIR(dir
))
1452 return permission(dir
,MAY_WRITE
| MAY_EXEC
, nd
);
1456 * O_DIRECTORY translates into forcing a directory lookup.
1458 static inline int lookup_flags(unsigned int f
)
1460 unsigned long retval
= LOOKUP_FOLLOW
;
1463 retval
&= ~LOOKUP_FOLLOW
;
1465 if (f
& O_DIRECTORY
)
1466 retval
|= LOOKUP_DIRECTORY
;
1472 * p1 and p2 should be directories on the same fs.
1474 struct dentry
*lock_rename(struct dentry
*p1
, struct dentry
*p2
)
1479 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1483 mutex_lock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1485 for (p
= p1
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1486 if (p
->d_parent
== p2
) {
1487 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1488 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1493 for (p
= p2
; p
->d_parent
!= p
; p
= p
->d_parent
) {
1494 if (p
->d_parent
== p1
) {
1495 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1496 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1501 mutex_lock_nested(&p1
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1502 mutex_lock_nested(&p2
->d_inode
->i_mutex
, I_MUTEX_CHILD
);
1506 void unlock_rename(struct dentry
*p1
, struct dentry
*p2
)
1508 mutex_unlock(&p1
->d_inode
->i_mutex
);
1510 mutex_unlock(&p2
->d_inode
->i_mutex
);
1511 mutex_unlock(&p1
->d_inode
->i_sb
->s_vfs_rename_mutex
);
1515 int vfs_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
1516 struct nameidata
*nd
)
1518 int error
= may_create(dir
, dentry
, nd
);
1523 if (!dir
->i_op
|| !dir
->i_op
->create
)
1524 return -EACCES
; /* shouldn't it be ENOSYS? */
1527 error
= security_inode_create(dir
, dentry
, mode
);
1531 error
= dir
->i_op
->create(dir
, dentry
, mode
, nd
);
1533 fsnotify_create(dir
, dentry
);
1537 int may_open(struct nameidata
*nd
, int acc_mode
, int flag
)
1539 struct dentry
*dentry
= nd
->dentry
;
1540 struct inode
*inode
= dentry
->d_inode
;
1546 if (S_ISLNK(inode
->i_mode
))
1549 if (S_ISDIR(inode
->i_mode
) && (flag
& FMODE_WRITE
))
1552 error
= vfs_permission(nd
, acc_mode
);
1557 * FIFO's, sockets and device files are special: they don't
1558 * actually live on the filesystem itself, and as such you
1559 * can write to them even if the filesystem is read-only.
1561 if (S_ISFIFO(inode
->i_mode
) || S_ISSOCK(inode
->i_mode
)) {
1563 } else if (S_ISBLK(inode
->i_mode
) || S_ISCHR(inode
->i_mode
)) {
1564 if (nd
->mnt
->mnt_flags
& MNT_NODEV
)
1568 } else if (IS_RDONLY(inode
) && (flag
& FMODE_WRITE
))
1571 * An append-only file must be opened in append mode for writing.
1573 if (IS_APPEND(inode
)) {
1574 if ((flag
& FMODE_WRITE
) && !(flag
& O_APPEND
))
1580 /* O_NOATIME can only be set by the owner or superuser */
1581 if (flag
& O_NOATIME
)
1582 if (current
->fsuid
!= inode
->i_uid
&& !capable(CAP_FOWNER
))
1586 * Ensure there are no outstanding leases on the file.
1588 error
= break_lease(inode
, flag
);
1592 if (flag
& O_TRUNC
) {
1593 error
= get_write_access(inode
);
1598 * Refuse to truncate files with mandatory locks held on them.
1600 error
= locks_verify_locked(inode
);
1604 error
= do_truncate(dentry
, 0, ATTR_MTIME
|ATTR_CTIME
, NULL
);
1606 put_write_access(inode
);
1610 if (flag
& FMODE_WRITE
)
1616 static int open_namei_create(struct nameidata
*nd
, struct path
*path
,
1620 struct dentry
*dir
= nd
->dentry
;
1622 if (!IS_POSIXACL(dir
->d_inode
))
1623 mode
&= ~current
->fs
->umask
;
1624 error
= vfs_create(dir
->d_inode
, path
->dentry
, mode
, nd
);
1625 mutex_unlock(&dir
->d_inode
->i_mutex
);
1627 nd
->dentry
= path
->dentry
;
1630 /* Don't check for write permission, don't truncate */
1631 return may_open(nd
, 0, flag
& ~O_TRUNC
);
1637 * namei for open - this is in fact almost the whole open-routine.
1639 * Note that the low bits of "flag" aren't the same as in the open
1640 * system call - they are 00 - no permissions needed
1641 * 01 - read permission needed
1642 * 10 - write permission needed
1643 * 11 - read/write permissions needed
1644 * which is a lot more logical, and also allows the "no perm" needed
1645 * for symlinks (where the permissions are checked later).
1648 int open_namei(int dfd
, const char *pathname
, int flag
,
1649 int mode
, struct nameidata
*nd
)
1651 int acc_mode
, error
;
1656 acc_mode
= ACC_MODE(flag
);
1658 /* O_TRUNC implies we need access checks for write permissions */
1660 acc_mode
|= MAY_WRITE
;
1662 /* Allow the LSM permission hook to distinguish append
1663 access from general write access. */
1664 if (flag
& O_APPEND
)
1665 acc_mode
|= MAY_APPEND
;
1668 * The simplest case - just a plain lookup.
1670 if (!(flag
& O_CREAT
)) {
1671 error
= path_lookup_open(dfd
, pathname
, lookup_flags(flag
),
1679 * Create - we need to know the parent.
1681 error
= path_lookup_create(dfd
,pathname
,LOOKUP_PARENT
,nd
,flag
,mode
);
1686 * We have the parent and last component. First of all, check
1687 * that we are not asked to creat(2) an obvious directory - that
1691 if (nd
->last_type
!= LAST_NORM
|| nd
->last
.name
[nd
->last
.len
])
1695 nd
->flags
&= ~LOOKUP_PARENT
;
1696 mutex_lock(&dir
->d_inode
->i_mutex
);
1697 path
.dentry
= lookup_hash(nd
);
1701 error
= PTR_ERR(path
.dentry
);
1702 if (IS_ERR(path
.dentry
)) {
1703 mutex_unlock(&dir
->d_inode
->i_mutex
);
1707 if (IS_ERR(nd
->intent
.open
.file
)) {
1708 mutex_unlock(&dir
->d_inode
->i_mutex
);
1709 error
= PTR_ERR(nd
->intent
.open
.file
);
1713 /* Negative dentry, just create the file */
1714 if (!path
.dentry
->d_inode
) {
1715 error
= open_namei_create(nd
, &path
, flag
, mode
);
1722 * It already exists.
1724 mutex_unlock(&dir
->d_inode
->i_mutex
);
1725 audit_inode_update(path
.dentry
->d_inode
);
1731 if (__follow_mount(&path
)) {
1733 if (flag
& O_NOFOLLOW
)
1738 if (!path
.dentry
->d_inode
)
1740 if (path
.dentry
->d_inode
->i_op
&& path
.dentry
->d_inode
->i_op
->follow_link
)
1743 path_to_nameidata(&path
, nd
);
1745 if (path
.dentry
->d_inode
&& S_ISDIR(path
.dentry
->d_inode
->i_mode
))
1748 error
= may_open(nd
, acc_mode
, flag
);
1754 dput_path(&path
, nd
);
1756 if (!IS_ERR(nd
->intent
.open
.file
))
1757 release_open_intent(nd
);
1763 if (flag
& O_NOFOLLOW
)
1766 * This is subtle. Instead of calling do_follow_link() we do the
1767 * thing by hands. The reason is that this way we have zero link_count
1768 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1769 * After that we have the parent and last component, i.e.
1770 * we are in the same situation as after the first path_walk().
1771 * Well, almost - if the last component is normal we get its copy
1772 * stored in nd->last.name and we will have to putname() it when we
1773 * are done. Procfs-like symlinks just set LAST_BIND.
1775 nd
->flags
|= LOOKUP_PARENT
;
1776 error
= security_inode_follow_link(path
.dentry
, nd
);
1779 error
= __do_follow_link(&path
, nd
);
1781 /* Does someone understand code flow here? Or it is only
1782 * me so stupid? Anathema to whoever designed this non-sense
1783 * with "intent.open".
1785 release_open_intent(nd
);
1788 nd
->flags
&= ~LOOKUP_PARENT
;
1789 if (nd
->last_type
== LAST_BIND
)
1792 if (nd
->last_type
!= LAST_NORM
)
1794 if (nd
->last
.name
[nd
->last
.len
]) {
1795 __putname(nd
->last
.name
);
1800 __putname(nd
->last
.name
);
1804 mutex_lock(&dir
->d_inode
->i_mutex
);
1805 path
.dentry
= lookup_hash(nd
);
1807 __putname(nd
->last
.name
);
1812 * lookup_create - lookup a dentry, creating it if it doesn't exist
1813 * @nd: nameidata info
1814 * @is_dir: directory flag
1816 * Simple function to lookup and return a dentry and create it
1817 * if it doesn't exist. Is SMP-safe.
1819 * Returns with nd->dentry->d_inode->i_mutex locked.
1821 struct dentry
*lookup_create(struct nameidata
*nd
, int is_dir
)
1823 struct dentry
*dentry
= ERR_PTR(-EEXIST
);
1825 mutex_lock_nested(&nd
->dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
1827 * Yucky last component or no last component at all?
1828 * (foo/., foo/.., /////)
1830 if (nd
->last_type
!= LAST_NORM
)
1832 nd
->flags
&= ~LOOKUP_PARENT
;
1833 nd
->flags
|= LOOKUP_CREATE
;
1834 nd
->intent
.open
.flags
= O_EXCL
;
1837 * Do the final lookup.
1839 dentry
= lookup_hash(nd
);
1844 * Special case - lookup gave negative, but... we had foo/bar/
1845 * From the vfs_mknod() POV we just have a negative dentry -
1846 * all is fine. Let's be bastards - you had / on the end, you've
1847 * been asking for (non-existent) directory. -ENOENT for you.
1849 if (!is_dir
&& nd
->last
.name
[nd
->last
.len
] && !dentry
->d_inode
)
1854 dentry
= ERR_PTR(-ENOENT
);
1858 EXPORT_SYMBOL_GPL(lookup_create
);
1860 int vfs_mknod(struct inode
*dir
, struct dentry
*dentry
, int mode
, dev_t dev
)
1862 int error
= may_create(dir
, dentry
, NULL
);
1867 if ((S_ISCHR(mode
) || S_ISBLK(mode
)) && !capable(CAP_MKNOD
))
1870 if (!dir
->i_op
|| !dir
->i_op
->mknod
)
1873 error
= security_inode_mknod(dir
, dentry
, mode
, dev
);
1878 error
= dir
->i_op
->mknod(dir
, dentry
, mode
, dev
);
1880 fsnotify_create(dir
, dentry
);
1884 asmlinkage
long sys_mknodat(int dfd
, const char __user
*filename
, int mode
,
1889 struct dentry
* dentry
;
1890 struct nameidata nd
;
1894 tmp
= getname(filename
);
1896 return PTR_ERR(tmp
);
1898 error
= do_path_lookup(dfd
, tmp
, LOOKUP_PARENT
, &nd
);
1901 dentry
= lookup_create(&nd
, 0);
1902 error
= PTR_ERR(dentry
);
1904 if (!IS_POSIXACL(nd
.dentry
->d_inode
))
1905 mode
&= ~current
->fs
->umask
;
1906 if (!IS_ERR(dentry
)) {
1907 switch (mode
& S_IFMT
) {
1908 case 0: case S_IFREG
:
1909 error
= vfs_create(nd
.dentry
->d_inode
,dentry
,mode
,&nd
);
1911 case S_IFCHR
: case S_IFBLK
:
1912 error
= vfs_mknod(nd
.dentry
->d_inode
,dentry
,mode
,
1913 new_decode_dev(dev
));
1915 case S_IFIFO
: case S_IFSOCK
:
1916 error
= vfs_mknod(nd
.dentry
->d_inode
,dentry
,mode
,0);
1926 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
1934 asmlinkage
long sys_mknod(const char __user
*filename
, int mode
, unsigned dev
)
1936 return sys_mknodat(AT_FDCWD
, filename
, mode
, dev
);
1939 int vfs_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
1941 int error
= may_create(dir
, dentry
, NULL
);
1946 if (!dir
->i_op
|| !dir
->i_op
->mkdir
)
1949 mode
&= (S_IRWXUGO
|S_ISVTX
);
1950 error
= security_inode_mkdir(dir
, dentry
, mode
);
1955 error
= dir
->i_op
->mkdir(dir
, dentry
, mode
);
1957 fsnotify_mkdir(dir
, dentry
);
1961 asmlinkage
long sys_mkdirat(int dfd
, const char __user
*pathname
, int mode
)
1965 struct dentry
*dentry
;
1966 struct nameidata nd
;
1968 tmp
= getname(pathname
);
1969 error
= PTR_ERR(tmp
);
1973 error
= do_path_lookup(dfd
, tmp
, LOOKUP_PARENT
, &nd
);
1976 dentry
= lookup_create(&nd
, 1);
1977 error
= PTR_ERR(dentry
);
1981 if (!IS_POSIXACL(nd
.dentry
->d_inode
))
1982 mode
&= ~current
->fs
->umask
;
1983 error
= vfs_mkdir(nd
.dentry
->d_inode
, dentry
, mode
);
1986 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
1994 asmlinkage
long sys_mkdir(const char __user
*pathname
, int mode
)
1996 return sys_mkdirat(AT_FDCWD
, pathname
, mode
);
2000 * We try to drop the dentry early: we should have
2001 * a usage count of 2 if we're the only user of this
2002 * dentry, and if that is true (possibly after pruning
2003 * the dcache), then we drop the dentry now.
2005 * A low-level filesystem can, if it choses, legally
2008 * if (!d_unhashed(dentry))
2011 * if it cannot handle the case of removing a directory
2012 * that is still in use by something else..
2014 void dentry_unhash(struct dentry
*dentry
)
2017 shrink_dcache_parent(dentry
);
2018 spin_lock(&dcache_lock
);
2019 spin_lock(&dentry
->d_lock
);
2020 if (atomic_read(&dentry
->d_count
) == 2)
2022 spin_unlock(&dentry
->d_lock
);
2023 spin_unlock(&dcache_lock
);
2026 int vfs_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2028 int error
= may_delete(dir
, dentry
, 1);
2033 if (!dir
->i_op
|| !dir
->i_op
->rmdir
)
2038 mutex_lock(&dentry
->d_inode
->i_mutex
);
2039 dentry_unhash(dentry
);
2040 if (d_mountpoint(dentry
))
2043 error
= security_inode_rmdir(dir
, dentry
);
2045 error
= dir
->i_op
->rmdir(dir
, dentry
);
2047 dentry
->d_inode
->i_flags
|= S_DEAD
;
2050 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2059 static long do_rmdir(int dfd
, const char __user
*pathname
)
2063 struct dentry
*dentry
;
2064 struct nameidata nd
;
2066 name
= getname(pathname
);
2068 return PTR_ERR(name
);
2070 error
= do_path_lookup(dfd
, name
, LOOKUP_PARENT
, &nd
);
2074 switch(nd
.last_type
) {
2085 mutex_lock_nested(&nd
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2086 dentry
= lookup_hash(&nd
);
2087 error
= PTR_ERR(dentry
);
2090 error
= vfs_rmdir(nd
.dentry
->d_inode
, dentry
);
2093 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2101 asmlinkage
long sys_rmdir(const char __user
*pathname
)
2103 return do_rmdir(AT_FDCWD
, pathname
);
2106 int vfs_unlink(struct inode
*dir
, struct dentry
*dentry
)
2108 int error
= may_delete(dir
, dentry
, 0);
2113 if (!dir
->i_op
|| !dir
->i_op
->unlink
)
2118 mutex_lock(&dentry
->d_inode
->i_mutex
);
2119 if (d_mountpoint(dentry
))
2122 error
= security_inode_unlink(dir
, dentry
);
2124 error
= dir
->i_op
->unlink(dir
, dentry
);
2126 mutex_unlock(&dentry
->d_inode
->i_mutex
);
2128 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2129 if (!error
&& !(dentry
->d_flags
& DCACHE_NFSFS_RENAMED
)) {
2137 * Make sure that the actual truncation of the file will occur outside its
2138 * directory's i_mutex. Truncate can take a long time if there is a lot of
2139 * writeout happening, and we don't want to prevent access to the directory
2140 * while waiting on the I/O.
2142 static long do_unlinkat(int dfd
, const char __user
*pathname
)
2146 struct dentry
*dentry
;
2147 struct nameidata nd
;
2148 struct inode
*inode
= NULL
;
2150 name
= getname(pathname
);
2152 return PTR_ERR(name
);
2154 error
= do_path_lookup(dfd
, name
, LOOKUP_PARENT
, &nd
);
2158 if (nd
.last_type
!= LAST_NORM
)
2160 mutex_lock_nested(&nd
.dentry
->d_inode
->i_mutex
, I_MUTEX_PARENT
);
2161 dentry
= lookup_hash(&nd
);
2162 error
= PTR_ERR(dentry
);
2163 if (!IS_ERR(dentry
)) {
2164 /* Why not before? Because we want correct error value */
2165 if (nd
.last
.name
[nd
.last
.len
])
2167 inode
= dentry
->d_inode
;
2169 atomic_inc(&inode
->i_count
);
2170 error
= vfs_unlink(nd
.dentry
->d_inode
, dentry
);
2174 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2176 iput(inode
); /* truncate the inode here */
2184 error
= !dentry
->d_inode
? -ENOENT
:
2185 S_ISDIR(dentry
->d_inode
->i_mode
) ? -EISDIR
: -ENOTDIR
;
2189 asmlinkage
long sys_unlinkat(int dfd
, const char __user
*pathname
, int flag
)
2191 if ((flag
& ~AT_REMOVEDIR
) != 0)
2194 if (flag
& AT_REMOVEDIR
)
2195 return do_rmdir(dfd
, pathname
);
2197 return do_unlinkat(dfd
, pathname
);
2200 asmlinkage
long sys_unlink(const char __user
*pathname
)
2202 return do_unlinkat(AT_FDCWD
, pathname
);
2205 int vfs_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *oldname
, int mode
)
2207 int error
= may_create(dir
, dentry
, NULL
);
2212 if (!dir
->i_op
|| !dir
->i_op
->symlink
)
2215 error
= security_inode_symlink(dir
, dentry
, oldname
);
2220 error
= dir
->i_op
->symlink(dir
, dentry
, oldname
);
2222 fsnotify_create(dir
, dentry
);
2226 asmlinkage
long sys_symlinkat(const char __user
*oldname
,
2227 int newdfd
, const char __user
*newname
)
2232 struct dentry
*dentry
;
2233 struct nameidata nd
;
2235 from
= getname(oldname
);
2237 return PTR_ERR(from
);
2238 to
= getname(newname
);
2239 error
= PTR_ERR(to
);
2243 error
= do_path_lookup(newdfd
, to
, LOOKUP_PARENT
, &nd
);
2246 dentry
= lookup_create(&nd
, 0);
2247 error
= PTR_ERR(dentry
);
2251 error
= vfs_symlink(nd
.dentry
->d_inode
, dentry
, from
, S_IALLUGO
);
2254 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2263 asmlinkage
long sys_symlink(const char __user
*oldname
, const char __user
*newname
)
2265 return sys_symlinkat(oldname
, AT_FDCWD
, newname
);
2268 int vfs_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*new_dentry
)
2270 struct inode
*inode
= old_dentry
->d_inode
;
2276 error
= may_create(dir
, new_dentry
, NULL
);
2280 if (dir
->i_sb
!= inode
->i_sb
)
2284 * A link to an append-only or immutable file cannot be created.
2286 if (IS_APPEND(inode
) || IS_IMMUTABLE(inode
))
2288 if (!dir
->i_op
|| !dir
->i_op
->link
)
2290 if (S_ISDIR(old_dentry
->d_inode
->i_mode
))
2293 error
= security_inode_link(old_dentry
, dir
, new_dentry
);
2297 mutex_lock(&old_dentry
->d_inode
->i_mutex
);
2299 error
= dir
->i_op
->link(old_dentry
, dir
, new_dentry
);
2300 mutex_unlock(&old_dentry
->d_inode
->i_mutex
);
2302 fsnotify_create(dir
, new_dentry
);
2307 * Hardlinks are often used in delicate situations. We avoid
2308 * security-related surprises by not following symlinks on the
2311 * We don't follow them on the oldname either to be compatible
2312 * with linux 2.0, and to avoid hard-linking to directories
2313 * and other special files. --ADM
2315 asmlinkage
long sys_linkat(int olddfd
, const char __user
*oldname
,
2316 int newdfd
, const char __user
*newname
,
2319 struct dentry
*new_dentry
;
2320 struct nameidata nd
, old_nd
;
2324 if ((flags
& ~AT_SYMLINK_FOLLOW
) != 0)
2327 to
= getname(newname
);
2331 error
= __user_walk_fd(olddfd
, oldname
,
2332 flags
& AT_SYMLINK_FOLLOW
? LOOKUP_FOLLOW
: 0,
2336 error
= do_path_lookup(newdfd
, to
, LOOKUP_PARENT
, &nd
);
2340 if (old_nd
.mnt
!= nd
.mnt
)
2342 new_dentry
= lookup_create(&nd
, 0);
2343 error
= PTR_ERR(new_dentry
);
2344 if (IS_ERR(new_dentry
))
2346 error
= vfs_link(old_nd
.dentry
, nd
.dentry
->d_inode
, new_dentry
);
2349 mutex_unlock(&nd
.dentry
->d_inode
->i_mutex
);
2353 path_release(&old_nd
);
2360 asmlinkage
long sys_link(const char __user
*oldname
, const char __user
*newname
)
2362 return sys_linkat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
, 0);
2366 * The worst of all namespace operations - renaming directory. "Perverted"
2367 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2369 * a) we can get into loop creation. Check is done in is_subdir().
2370 * b) race potential - two innocent renames can create a loop together.
2371 * That's where 4.4 screws up. Current fix: serialization on
2372 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
2374 * c) we have to lock _three_ objects - parents and victim (if it exists).
2375 * And that - after we got ->i_mutex on parents (until then we don't know
2376 * whether the target exists). Solution: try to be smart with locking
2377 * order for inodes. We rely on the fact that tree topology may change
2378 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
2379 * move will be locked. Thus we can rank directories by the tree
2380 * (ancestors first) and rank all non-directories after them.
2381 * That works since everybody except rename does "lock parent, lookup,
2382 * lock child" and rename is under ->s_vfs_rename_mutex.
2383 * HOWEVER, it relies on the assumption that any object with ->lookup()
2384 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2385 * we'd better make sure that there's no link(2) for them.
2386 * d) some filesystems don't support opened-but-unlinked directories,
2387 * either because of layout or because they are not ready to deal with
2388 * all cases correctly. The latter will be fixed (taking this sort of
2389 * stuff into VFS), but the former is not going away. Solution: the same
2390 * trick as in rmdir().
2391 * e) conversion from fhandle to dentry may come in the wrong moment - when
2392 * we are removing the target. Solution: we will have to grab ->i_mutex
2393 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
2394 * ->i_mutex on parents, which works but leads to some truely excessive
2397 static int vfs_rename_dir(struct inode
*old_dir
, struct dentry
*old_dentry
,
2398 struct inode
*new_dir
, struct dentry
*new_dentry
)
2401 struct inode
*target
;
2404 * If we are going to change the parent - check write permissions,
2405 * we'll need to flip '..'.
2407 if (new_dir
!= old_dir
) {
2408 error
= permission(old_dentry
->d_inode
, MAY_WRITE
, NULL
);
2413 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2417 target
= new_dentry
->d_inode
;
2419 mutex_lock(&target
->i_mutex
);
2420 dentry_unhash(new_dentry
);
2422 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2425 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2428 target
->i_flags
|= S_DEAD
;
2429 mutex_unlock(&target
->i_mutex
);
2430 if (d_unhashed(new_dentry
))
2431 d_rehash(new_dentry
);
2435 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2436 d_move(old_dentry
,new_dentry
);
2440 static int vfs_rename_other(struct inode
*old_dir
, struct dentry
*old_dentry
,
2441 struct inode
*new_dir
, struct dentry
*new_dentry
)
2443 struct inode
*target
;
2446 error
= security_inode_rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2451 target
= new_dentry
->d_inode
;
2453 mutex_lock(&target
->i_mutex
);
2454 if (d_mountpoint(old_dentry
)||d_mountpoint(new_dentry
))
2457 error
= old_dir
->i_op
->rename(old_dir
, old_dentry
, new_dir
, new_dentry
);
2459 if (!(old_dir
->i_sb
->s_type
->fs_flags
& FS_RENAME_DOES_D_MOVE
))
2460 d_move(old_dentry
, new_dentry
);
2463 mutex_unlock(&target
->i_mutex
);
2468 int vfs_rename(struct inode
*old_dir
, struct dentry
*old_dentry
,
2469 struct inode
*new_dir
, struct dentry
*new_dentry
)
2472 int is_dir
= S_ISDIR(old_dentry
->d_inode
->i_mode
);
2473 const char *old_name
;
2475 if (old_dentry
->d_inode
== new_dentry
->d_inode
)
2478 error
= may_delete(old_dir
, old_dentry
, is_dir
);
2482 if (!new_dentry
->d_inode
)
2483 error
= may_create(new_dir
, new_dentry
, NULL
);
2485 error
= may_delete(new_dir
, new_dentry
, is_dir
);
2489 if (!old_dir
->i_op
|| !old_dir
->i_op
->rename
)
2492 DQUOT_INIT(old_dir
);
2493 DQUOT_INIT(new_dir
);
2495 old_name
= fsnotify_oldname_init(old_dentry
->d_name
.name
);
2498 error
= vfs_rename_dir(old_dir
,old_dentry
,new_dir
,new_dentry
);
2500 error
= vfs_rename_other(old_dir
,old_dentry
,new_dir
,new_dentry
);
2502 const char *new_name
= old_dentry
->d_name
.name
;
2503 fsnotify_move(old_dir
, new_dir
, old_name
, new_name
, is_dir
,
2504 new_dentry
->d_inode
, old_dentry
->d_inode
);
2506 fsnotify_oldname_free(old_name
);
2511 static int do_rename(int olddfd
, const char *oldname
,
2512 int newdfd
, const char *newname
)
2515 struct dentry
* old_dir
, * new_dir
;
2516 struct dentry
* old_dentry
, *new_dentry
;
2517 struct dentry
* trap
;
2518 struct nameidata oldnd
, newnd
;
2520 error
= do_path_lookup(olddfd
, oldname
, LOOKUP_PARENT
, &oldnd
);
2524 error
= do_path_lookup(newdfd
, newname
, LOOKUP_PARENT
, &newnd
);
2529 if (oldnd
.mnt
!= newnd
.mnt
)
2532 old_dir
= oldnd
.dentry
;
2534 if (oldnd
.last_type
!= LAST_NORM
)
2537 new_dir
= newnd
.dentry
;
2538 if (newnd
.last_type
!= LAST_NORM
)
2541 trap
= lock_rename(new_dir
, old_dir
);
2543 old_dentry
= lookup_hash(&oldnd
);
2544 error
= PTR_ERR(old_dentry
);
2545 if (IS_ERR(old_dentry
))
2547 /* source must exist */
2549 if (!old_dentry
->d_inode
)
2551 /* unless the source is a directory trailing slashes give -ENOTDIR */
2552 if (!S_ISDIR(old_dentry
->d_inode
->i_mode
)) {
2554 if (oldnd
.last
.name
[oldnd
.last
.len
])
2556 if (newnd
.last
.name
[newnd
.last
.len
])
2559 /* source should not be ancestor of target */
2561 if (old_dentry
== trap
)
2563 new_dentry
= lookup_hash(&newnd
);
2564 error
= PTR_ERR(new_dentry
);
2565 if (IS_ERR(new_dentry
))
2567 /* target should not be an ancestor of source */
2569 if (new_dentry
== trap
)
2572 error
= vfs_rename(old_dir
->d_inode
, old_dentry
,
2573 new_dir
->d_inode
, new_dentry
);
2579 unlock_rename(new_dir
, old_dir
);
2581 path_release(&newnd
);
2583 path_release(&oldnd
);
2588 asmlinkage
long sys_renameat(int olddfd
, const char __user
*oldname
,
2589 int newdfd
, const char __user
*newname
)
2595 from
= getname(oldname
);
2597 return PTR_ERR(from
);
2598 to
= getname(newname
);
2599 error
= PTR_ERR(to
);
2601 error
= do_rename(olddfd
, from
, newdfd
, to
);
2608 asmlinkage
long sys_rename(const char __user
*oldname
, const char __user
*newname
)
2610 return sys_renameat(AT_FDCWD
, oldname
, AT_FDCWD
, newname
);
2613 int vfs_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
, const char *link
)
2617 len
= PTR_ERR(link
);
2622 if (len
> (unsigned) buflen
)
2624 if (copy_to_user(buffer
, link
, len
))
2631 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2632 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2633 * using) it for any given inode is up to filesystem.
2635 int generic_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2637 struct nameidata nd
;
2641 cookie
= dentry
->d_inode
->i_op
->follow_link(dentry
, &nd
);
2642 if (!IS_ERR(cookie
)) {
2643 int res
= vfs_readlink(dentry
, buffer
, buflen
, nd_get_link(&nd
));
2644 if (dentry
->d_inode
->i_op
->put_link
)
2645 dentry
->d_inode
->i_op
->put_link(dentry
, &nd
, cookie
);
2646 cookie
= ERR_PTR(res
);
2648 return PTR_ERR(cookie
);
2651 int vfs_follow_link(struct nameidata
*nd
, const char *link
)
2653 return __vfs_follow_link(nd
, link
);
2656 /* get the link contents into pagecache */
2657 static char *page_getlink(struct dentry
* dentry
, struct page
**ppage
)
2660 struct address_space
*mapping
= dentry
->d_inode
->i_mapping
;
2661 page
= read_mapping_page(mapping
, 0, NULL
);
2668 int page_readlink(struct dentry
*dentry
, char __user
*buffer
, int buflen
)
2670 struct page
*page
= NULL
;
2671 char *s
= page_getlink(dentry
, &page
);
2672 int res
= vfs_readlink(dentry
,buffer
,buflen
,s
);
2675 page_cache_release(page
);
2680 void *page_follow_link_light(struct dentry
*dentry
, struct nameidata
*nd
)
2682 struct page
*page
= NULL
;
2683 nd_set_link(nd
, page_getlink(dentry
, &page
));
2687 void page_put_link(struct dentry
*dentry
, struct nameidata
*nd
, void *cookie
)
2689 struct page
*page
= cookie
;
2693 page_cache_release(page
);
2697 int __page_symlink(struct inode
*inode
, const char *symname
, int len
,
2700 struct address_space
*mapping
= inode
->i_mapping
;
2707 page
= find_or_create_page(mapping
, 0, gfp_mask
);
2710 err
= mapping
->a_ops
->prepare_write(NULL
, page
, 0, len
-1);
2711 if (err
== AOP_TRUNCATED_PAGE
) {
2712 page_cache_release(page
);
2717 kaddr
= kmap_atomic(page
, KM_USER0
);
2718 memcpy(kaddr
, symname
, len
-1);
2719 kunmap_atomic(kaddr
, KM_USER0
);
2720 err
= mapping
->a_ops
->commit_write(NULL
, page
, 0, len
-1);
2721 if (err
== AOP_TRUNCATED_PAGE
) {
2722 page_cache_release(page
);
2728 * Notice that we are _not_ going to block here - end of page is
2729 * unmapped, so this will only try to map the rest of page, see
2730 * that it is unmapped (typically even will not look into inode -
2731 * ->i_size will be enough for everything) and zero it out.
2732 * OTOH it's obviously correct and should make the page up-to-date.
2734 if (!PageUptodate(page
)) {
2735 err
= mapping
->a_ops
->readpage(NULL
, page
);
2736 if (err
!= AOP_TRUNCATED_PAGE
)
2737 wait_on_page_locked(page
);
2741 page_cache_release(page
);
2744 mark_inode_dirty(inode
);
2748 page_cache_release(page
);
2753 int page_symlink(struct inode
*inode
, const char *symname
, int len
)
2755 return __page_symlink(inode
, symname
, len
,
2756 mapping_gfp_mask(inode
->i_mapping
));
2759 const struct inode_operations page_symlink_inode_operations
= {
2760 .readlink
= generic_readlink
,
2761 .follow_link
= page_follow_link_light
,
2762 .put_link
= page_put_link
,
2765 EXPORT_SYMBOL(__user_walk
);
2766 EXPORT_SYMBOL(__user_walk_fd
);
2767 EXPORT_SYMBOL(follow_down
);
2768 EXPORT_SYMBOL(follow_up
);
2769 EXPORT_SYMBOL(get_write_access
); /* binfmt_aout */
2770 EXPORT_SYMBOL(getname
);
2771 EXPORT_SYMBOL(lock_rename
);
2772 EXPORT_SYMBOL(lookup_one_len
);
2773 EXPORT_SYMBOL(page_follow_link_light
);
2774 EXPORT_SYMBOL(page_put_link
);
2775 EXPORT_SYMBOL(page_readlink
);
2776 EXPORT_SYMBOL(__page_symlink
);
2777 EXPORT_SYMBOL(page_symlink
);
2778 EXPORT_SYMBOL(page_symlink_inode_operations
);
2779 EXPORT_SYMBOL(path_lookup
);
2780 EXPORT_SYMBOL(path_release
);
2781 EXPORT_SYMBOL(path_walk
);
2782 EXPORT_SYMBOL(permission
);
2783 EXPORT_SYMBOL(vfs_permission
);
2784 EXPORT_SYMBOL(file_permission
);
2785 EXPORT_SYMBOL(unlock_rename
);
2786 EXPORT_SYMBOL(vfs_create
);
2787 EXPORT_SYMBOL(vfs_follow_link
);
2788 EXPORT_SYMBOL(vfs_link
);
2789 EXPORT_SYMBOL(vfs_mkdir
);
2790 EXPORT_SYMBOL(vfs_mknod
);
2791 EXPORT_SYMBOL(generic_permission
);
2792 EXPORT_SYMBOL(vfs_readlink
);
2793 EXPORT_SYMBOL(vfs_rename
);
2794 EXPORT_SYMBOL(vfs_rmdir
);
2795 EXPORT_SYMBOL(vfs_symlink
);
2796 EXPORT_SYMBOL(vfs_unlink
);
2797 EXPORT_SYMBOL(dentry_unhash
);
2798 EXPORT_SYMBOL(generic_readlink
);