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/personality.h>
26 #include <linux/security.h>
27 #include <linux/syscalls.h>
28 #include <linux/mount.h>
29 #include <linux/audit.h>
30 #include <linux/capability.h>
31 #include <linux/file.h>
32 #include <linux/fcntl.h>
33 #include <linux/device_cgroup.h>
34 #include <asm/namei.h>
35 #include <asm/uaccess.h>
37 #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
39 /* [Feb-1997 T. Schoebel-Theuer]
40 * Fundamental changes in the pathname lookup mechanisms (namei)
41 * were necessary because of omirr. The reason is that omirr needs
42 * to know the _real_ pathname, not the user-supplied one, in case
43 * of symlinks (and also when transname replacements occur).
45 * The new code replaces the old recursive symlink resolution with
46 * an iterative one (in case of non-nested symlink chains). It does
47 * this with calls to <fs>_follow_link().
48 * As a side effect, dir_namei(), _namei() and follow_link() are now
49 * replaced with a single function lookup_dentry() that can handle all
50 * the special cases of the former code.
52 * With the new dcache, the pathname is stored at each inode, at least as
53 * long as the refcount of the inode is positive. As a side effect, the
54 * size of the dcache depends on the inode cache and thus is dynamic.
56 * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink
57 * resolution to correspond with current state of the code.
59 * Note that the symlink resolution is not *completely* iterative.
60 * There is still a significant amount of tail- and mid- recursion in
61 * the algorithm. Also, note that <fs>_readlink() is not used in
62 * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink()
63 * may return different results than <fs>_follow_link(). Many virtual
64 * filesystems (including /proc) exhibit this behavior.
67 /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation:
68 * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL
69 * and the name already exists in form of a symlink, try to create the new
70 * name indicated by the symlink. The old code always complained that the
71 * name already exists, due to not following the symlink even if its target
72 * is nonexistent. The new semantics affects also mknod() and link() when
73 * the name is a symlink pointing to a non-existant name.
75 * I don't know which semantics is the right one, since I have no access
76 * to standards. But I found by trial that HP-UX 9.0 has the full "new"
77 * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the
78 * "old" one. Personally, I think the new semantics is much more logical.
79 * Note that "ln old new" where "new" is a symlink pointing to a non-existing
80 * file does succeed in both HP-UX and SunOs, but not in Solaris
81 * and in the old Linux semantics.
84 /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink
85 * semantics. See the comments in "open_namei" and "do_link" below.
87 * [10-Sep-98 Alan Modra] Another symlink change.
90 /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks:
91 * inside the path - always follow.
92 * in the last component in creation/removal/renaming - never follow.
93 * if LOOKUP_FOLLOW passed - follow.
94 * if the pathname has trailing slashes - follow.
95 * otherwise - don't follow.
96 * (applied in that order).
98 * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT
99 * restored for 2.4. This is the last surviving part of old 4.2BSD bug.
100 * During the 2.4 we need to fix the userland stuff depending on it -
101 * hopefully we will be able to get rid of that wart in 2.5. So far only
102 * XEmacs seems to be relying on it...
105 * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland)
106 * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives
107 * any extra contention...
110 static int __link_path_walk(const char *name, struct nameidata *nd);
112 /* In order to reduce some races, while at the same time doing additional
113 * checking and hopefully speeding things up, we copy filenames to the
114 * kernel data space before using them..
116 * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
117 * PATH_MAX includes the nul terminator --RR.
119 static int do_getname(const char __user *filename, char *page)
122 unsigned long len = PATH_MAX;
124 if (!segment_eq(get_fs(), KERNEL_DS)) {
125 if ((unsigned long) filename >= TASK_SIZE)
127 if (TASK_SIZE - (unsigned long) filename < PATH_MAX)
128 len = TASK_SIZE - (unsigned long) filename;
131 retval = strncpy_from_user(page, filename, len);
135 return -ENAMETOOLONG;
141 char * getname(const char __user * filename)
145 result = ERR_PTR(-ENOMEM);
148 int retval = do_getname(filename, tmp);
153 result = ERR_PTR(retval);
156 audit_getname(result);
160 #ifdef CONFIG_AUDITSYSCALL
161 void putname(const char *name)
163 if (unlikely(!audit_dummy_context()))
168 EXPORT_SYMBOL(putname);
173 * generic_permission - check for access rights on a Posix-like filesystem
174 * @inode: inode to check access rights for
175 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
176 * @check_acl: optional callback to check for Posix ACLs
178 * Used to check for read/write/execute permissions on a file.
179 * We use "fsuid" for this, letting us set arbitrary permissions
180 * for filesystem access without changing the "normal" uids which
181 * are used for other things..
183 int generic_permission(struct inode *inode, int mask,
184 int (*check_acl)(struct inode *inode, int mask))
186 umode_t mode = inode->i_mode;
188 mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
190 if (current->fsuid == inode->i_uid)
193 if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) {
194 int error = check_acl(inode, mask);
195 if (error == -EACCES)
196 goto check_capabilities;
197 else if (error != -EAGAIN)
201 if (in_group_p(inode->i_gid))
206 * If the DACs are ok we don't need any capability check.
208 if ((mask & ~mode) == 0)
213 * Read/write DACs are always overridable.
214 * Executable DACs are overridable if at least one exec bit is set.
216 if (!(mask & MAY_EXEC) ||
217 (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
218 if (capable(CAP_DAC_OVERRIDE))
222 * Searching includes executable on directories, else just read.
224 if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
225 if (capable(CAP_DAC_READ_SEARCH))
231 int permission(struct inode *inode, int mask, struct nameidata *nd)
234 struct vfsmount *mnt = NULL;
239 if (mask & MAY_WRITE) {
240 umode_t mode = inode->i_mode;
243 * Nobody gets write access to a read-only fs.
245 if (IS_RDONLY(inode) &&
246 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
250 * Nobody gets write access to an immutable file.
252 if (IS_IMMUTABLE(inode))
256 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
258 * MAY_EXEC on regular files is denied if the fs is mounted
259 * with the "noexec" flag.
261 if (mnt && (mnt->mnt_flags & MNT_NOEXEC))
265 /* Ordinary permission routines do not understand MAY_APPEND. */
266 if (inode->i_op && inode->i_op->permission) {
269 if (nd->flags & LOOKUP_ACCESS)
271 if (nd->flags & LOOKUP_CHDIR)
273 if (nd->flags & LOOKUP_OPEN)
276 retval = inode->i_op->permission(inode, mask | extra);
279 * Exec permission on a regular file is denied if none
280 * of the execute bits are set.
282 * This check should be done by the ->permission()
285 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
286 !(inode->i_mode & S_IXUGO))
290 retval = generic_permission(inode, mask, NULL);
295 retval = devcgroup_inode_permission(inode, mask);
299 return security_inode_permission(inode,
300 mask & (MAY_READ|MAY_WRITE|MAY_EXEC), nd);
304 * vfs_permission - check for access rights to a given path
305 * @nd: lookup result that describes the path
306 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
308 * Used to check for read/write/execute permissions on a path.
309 * We use "fsuid" for this, letting us set arbitrary permissions
310 * for filesystem access without changing the "normal" uids which
311 * are used for other things.
313 int vfs_permission(struct nameidata *nd, int mask)
315 return permission(nd->path.dentry->d_inode, mask, nd);
319 * file_permission - check for additional access rights to a given file
320 * @file: file to check access rights for
321 * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC)
323 * Used to check for read/write/execute permissions on an already opened
327 * Do not use this function in new code. All access checks should
328 * be done using vfs_permission().
330 int file_permission(struct file *file, int mask)
332 return permission(file->f_path.dentry->d_inode, mask, NULL);
336 * get_write_access() gets write permission for a file.
337 * put_write_access() releases this write permission.
338 * This is used for regular files.
339 * We cannot support write (and maybe mmap read-write shared) accesses and
340 * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode
341 * can have the following values:
342 * 0: no writers, no VM_DENYWRITE mappings
343 * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist
344 * > 0: (i_writecount) users are writing to the file.
346 * Normally we operate on that counter with atomic_{inc,dec} and it's safe
347 * except for the cases where we don't hold i_writecount yet. Then we need to
348 * use {get,deny}_write_access() - these functions check the sign and refuse
349 * to do the change if sign is wrong. Exclusion between them is provided by
350 * the inode->i_lock spinlock.
353 int get_write_access(struct inode * inode)
355 spin_lock(&inode->i_lock);
356 if (atomic_read(&inode->i_writecount) < 0) {
357 spin_unlock(&inode->i_lock);
360 atomic_inc(&inode->i_writecount);
361 spin_unlock(&inode->i_lock);
366 int deny_write_access(struct file * file)
368 struct inode *inode = file->f_path.dentry->d_inode;
370 spin_lock(&inode->i_lock);
371 if (atomic_read(&inode->i_writecount) > 0) {
372 spin_unlock(&inode->i_lock);
375 atomic_dec(&inode->i_writecount);
376 spin_unlock(&inode->i_lock);
382 * path_get - get a reference to a path
383 * @path: path to get the reference to
385 * Given a path increment the reference count to the dentry and the vfsmount.
387 void path_get(struct path *path)
392 EXPORT_SYMBOL(path_get);
395 * path_put - put a reference to a path
396 * @path: path to put the reference to
398 * Given a path decrement the reference count to the dentry and the vfsmount.
400 void path_put(struct path *path)
405 EXPORT_SYMBOL(path_put);
408 * release_open_intent - free up open intent resources
409 * @nd: pointer to nameidata
411 void release_open_intent(struct nameidata *nd)
413 if (nd->intent.open.file->f_path.dentry == NULL)
414 put_filp(nd->intent.open.file);
416 fput(nd->intent.open.file);
419 static inline struct dentry *
420 do_revalidate(struct dentry *dentry, struct nameidata *nd)
422 int status = dentry->d_op->d_revalidate(dentry, nd);
423 if (unlikely(status <= 0)) {
425 * The dentry failed validation.
426 * If d_revalidate returned 0 attempt to invalidate
427 * the dentry otherwise d_revalidate is asking us
428 * to return a fail status.
431 if (!d_invalidate(dentry)) {
437 dentry = ERR_PTR(status);
444 * Internal lookup() using the new generic dcache.
447 static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
449 struct dentry * dentry = __d_lookup(parent, name);
451 /* lockess __d_lookup may fail due to concurrent d_move()
452 * in some unrelated directory, so try with d_lookup
455 dentry = d_lookup(parent, name);
457 if (dentry && dentry->d_op && dentry->d_op->d_revalidate)
458 dentry = do_revalidate(dentry, nd);
464 * Short-cut version of permission(), for calling by
465 * path_walk(), when dcache lock is held. Combines parts
466 * of permission() and generic_permission(), and tests ONLY for
467 * MAY_EXEC permission.
469 * If appropriate, check DAC only. If not appropriate, or
470 * short-cut DAC fails, then call permission() to do more
471 * complete permission check.
473 static int exec_permission_lite(struct inode *inode,
474 struct nameidata *nd)
476 umode_t mode = inode->i_mode;
478 if (inode->i_op && inode->i_op->permission)
481 if (current->fsuid == inode->i_uid)
483 else if (in_group_p(inode->i_gid))
489 if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE))
492 if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE))
495 if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH))
500 return security_inode_permission(inode, MAY_EXEC, nd);
504 * This is called when everything else fails, and we actually have
505 * to go to the low-level filesystem to find out what we should do..
507 * We get the directory semaphore, and after getting that we also
508 * make sure that nobody added the entry to the dcache in the meantime..
511 static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd)
513 struct dentry * result;
514 struct inode *dir = parent->d_inode;
516 mutex_lock(&dir->i_mutex);
518 * First re-do the cached lookup just in case it was created
519 * while we waited for the directory semaphore..
521 * FIXME! This could use version numbering or similar to
522 * avoid unnecessary cache lookups.
524 * The "dcache_lock" is purely to protect the RCU list walker
525 * from concurrent renames at this point (we mustn't get false
526 * negatives from the RCU list walk here, unlike the optimistic
529 * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup
531 result = d_lookup(parent, name);
533 struct dentry *dentry;
535 /* Don't create child dentry for a dead directory. */
536 result = ERR_PTR(-ENOENT);
540 dentry = d_alloc(parent, name);
541 result = ERR_PTR(-ENOMEM);
543 result = dir->i_op->lookup(dir, dentry, nd);
550 mutex_unlock(&dir->i_mutex);
555 * Uhhuh! Nasty case: the cache was re-populated while
556 * we waited on the semaphore. Need to revalidate.
558 mutex_unlock(&dir->i_mutex);
559 if (result->d_op && result->d_op->d_revalidate) {
560 result = do_revalidate(result, nd);
562 result = ERR_PTR(-ENOENT);
567 static int __emul_lookup_dentry(const char *, struct nameidata *);
570 static __always_inline int
571 walk_init_root(const char *name, struct nameidata *nd)
573 struct fs_struct *fs = current->fs;
575 read_lock(&fs->lock);
576 if (fs->altroot.dentry && !(nd->flags & LOOKUP_NOALT)) {
577 nd->path = fs->altroot;
578 path_get(&fs->altroot);
579 read_unlock(&fs->lock);
580 if (__emul_lookup_dentry(name,nd))
582 read_lock(&fs->lock);
586 read_unlock(&fs->lock);
591 * Wrapper to retry pathname resolution whenever the underlying
592 * file system returns an ESTALE.
594 * Retry the whole path once, forcing real lookup requests
595 * instead of relying on the dcache.
597 static __always_inline int link_path_walk(const char *name, struct nameidata *nd)
599 struct path save = nd->path;
602 /* make sure the stuff we saved doesn't go away */
605 result = __link_path_walk(name, nd);
606 if (result == -ESTALE) {
607 /* nd->path had been dropped */
610 nd->flags |= LOOKUP_REVAL;
611 result = __link_path_walk(name, nd);
619 static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
628 if (!walk_init_root(link, nd))
629 /* weird __emul_prefix() stuff did it */
632 res = link_path_walk(link, nd);
634 if (nd->depth || res || nd->last_type!=LAST_NORM)
637 * If it is an iterative symlinks resolution in open_namei() we
638 * have to copy the last component. And all that crap because of
639 * bloody create() on broken symlinks. Furrfu...
642 if (unlikely(!name)) {
646 strcpy(name, nd->last.name);
647 nd->last.name = name;
651 return PTR_ERR(link);
654 static void path_put_conditional(struct path *path, struct nameidata *nd)
657 if (path->mnt != nd->path.mnt)
661 static inline void path_to_nameidata(struct path *path, struct nameidata *nd)
663 dput(nd->path.dentry);
664 if (nd->path.mnt != path->mnt)
665 mntput(nd->path.mnt);
666 nd->path.mnt = path->mnt;
667 nd->path.dentry = path->dentry;
670 static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd)
674 struct dentry *dentry = path->dentry;
676 touch_atime(path->mnt, dentry);
677 nd_set_link(nd, NULL);
679 if (path->mnt != nd->path.mnt) {
680 path_to_nameidata(path, nd);
684 cookie = dentry->d_inode->i_op->follow_link(dentry, nd);
685 error = PTR_ERR(cookie);
686 if (!IS_ERR(cookie)) {
687 char *s = nd_get_link(nd);
690 error = __vfs_follow_link(nd, s);
691 if (dentry->d_inode->i_op->put_link)
692 dentry->d_inode->i_op->put_link(dentry, nd, cookie);
700 * This limits recursive symlink follows to 8, while
701 * limiting consecutive symlinks to 40.
703 * Without that kind of total limit, nasty chains of consecutive
704 * symlinks can cause almost arbitrarily long lookups.
706 static inline int do_follow_link(struct path *path, struct nameidata *nd)
709 if (current->link_count >= MAX_NESTED_LINKS)
711 if (current->total_link_count >= 40)
713 BUG_ON(nd->depth >= MAX_NESTED_LINKS);
715 err = security_inode_follow_link(path->dentry, nd);
718 current->link_count++;
719 current->total_link_count++;
721 err = __do_follow_link(path, nd);
722 current->link_count--;
726 path_put_conditional(path, nd);
731 int follow_up(struct vfsmount **mnt, struct dentry **dentry)
733 struct vfsmount *parent;
734 struct dentry *mountpoint;
735 spin_lock(&vfsmount_lock);
736 parent=(*mnt)->mnt_parent;
737 if (parent == *mnt) {
738 spin_unlock(&vfsmount_lock);
742 mountpoint=dget((*mnt)->mnt_mountpoint);
743 spin_unlock(&vfsmount_lock);
745 *dentry = mountpoint;
751 /* no need for dcache_lock, as serialization is taken care in
754 static int __follow_mount(struct path *path)
757 while (d_mountpoint(path->dentry)) {
758 struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry);
765 path->dentry = dget(mounted->mnt_root);
771 static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
773 while (d_mountpoint(*dentry)) {
774 struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
780 *dentry = dget(mounted->mnt_root);
784 /* no need for dcache_lock, as serialization is taken care in
787 int follow_down(struct vfsmount **mnt, struct dentry **dentry)
789 struct vfsmount *mounted;
791 mounted = lookup_mnt(*mnt, *dentry);
796 *dentry = dget(mounted->mnt_root);
802 static __always_inline void follow_dotdot(struct nameidata *nd)
804 struct fs_struct *fs = current->fs;
807 struct vfsmount *parent;
808 struct dentry *old = nd->path.dentry;
810 read_lock(&fs->lock);
811 if (nd->path.dentry == fs->root.dentry &&
812 nd->path.mnt == fs->root.mnt) {
813 read_unlock(&fs->lock);
816 read_unlock(&fs->lock);
817 spin_lock(&dcache_lock);
818 if (nd->path.dentry != nd->path.mnt->mnt_root) {
819 nd->path.dentry = dget(nd->path.dentry->d_parent);
820 spin_unlock(&dcache_lock);
824 spin_unlock(&dcache_lock);
825 spin_lock(&vfsmount_lock);
826 parent = nd->path.mnt->mnt_parent;
827 if (parent == nd->path.mnt) {
828 spin_unlock(&vfsmount_lock);
832 nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint);
833 spin_unlock(&vfsmount_lock);
835 mntput(nd->path.mnt);
836 nd->path.mnt = parent;
838 follow_mount(&nd->path.mnt, &nd->path.dentry);
842 * It's more convoluted than I'd like it to be, but... it's still fairly
843 * small and for now I'd prefer to have fast path as straight as possible.
844 * It _is_ time-critical.
846 static int do_lookup(struct nameidata *nd, struct qstr *name,
849 struct vfsmount *mnt = nd->path.mnt;
850 struct dentry *dentry = __d_lookup(nd->path.dentry, name);
854 if (dentry->d_op && dentry->d_op->d_revalidate)
855 goto need_revalidate;
858 path->dentry = dentry;
859 __follow_mount(path);
863 dentry = real_lookup(nd->path.dentry, name, nd);
869 dentry = do_revalidate(dentry, nd);
877 return PTR_ERR(dentry);
882 * This is the basic name resolution function, turning a pathname into
883 * the final dentry. We expect 'base' to be positive and a directory.
885 * Returns 0 and nd will have valid dentry and mnt on success.
886 * Returns error and drops reference to input namei data on failure.
888 static int __link_path_walk(const char *name, struct nameidata *nd)
893 unsigned int lookup_flags = nd->flags;
900 inode = nd->path.dentry->d_inode;
902 lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
904 /* At this point we know we have a real path component. */
910 nd->flags |= LOOKUP_CONTINUE;
911 err = exec_permission_lite(inode, nd);
913 err = vfs_permission(nd, MAY_EXEC);
918 c = *(const unsigned char *)name;
920 hash = init_name_hash();
923 hash = partial_name_hash(c, hash);
924 c = *(const unsigned char *)name;
925 } while (c && (c != '/'));
926 this.len = name - (const char *) this.name;
927 this.hash = end_name_hash(hash);
929 /* remove trailing slashes? */
932 while (*++name == '/');
934 goto last_with_slashes;
937 * "." and ".." are special - ".." especially so because it has
938 * to be able to know about the current root directory and
939 * parent relationships.
941 if (this.name[0] == '.') switch (this.len) {
945 if (this.name[1] != '.')
948 inode = nd->path.dentry->d_inode;
954 * See if the low-level filesystem might want
955 * to use its own hash..
957 if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) {
958 err = nd->path.dentry->d_op->d_hash(nd->path.dentry,
963 /* This does the actual lookups.. */
964 err = do_lookup(nd, &this, &next);
969 inode = next.dentry->d_inode;
976 if (inode->i_op->follow_link) {
977 err = do_follow_link(&next, nd);
981 inode = nd->path.dentry->d_inode;
988 path_to_nameidata(&next, nd);
990 if (!inode->i_op->lookup)
993 /* here ends the main loop */
996 lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
998 /* Clear LOOKUP_CONTINUE iff it was previously unset */
999 nd->flags &= lookup_flags | ~LOOKUP_CONTINUE;
1000 if (lookup_flags & LOOKUP_PARENT)
1002 if (this.name[0] == '.') switch (this.len) {
1006 if (this.name[1] != '.')
1009 inode = nd->path.dentry->d_inode;
1014 if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) {
1015 err = nd->path.dentry->d_op->d_hash(nd->path.dentry,
1020 err = do_lookup(nd, &this, &next);
1023 inode = next.dentry->d_inode;
1024 if ((lookup_flags & LOOKUP_FOLLOW)
1025 && inode && inode->i_op && inode->i_op->follow_link) {
1026 err = do_follow_link(&next, nd);
1029 inode = nd->path.dentry->d_inode;
1031 path_to_nameidata(&next, nd);
1035 if (lookup_flags & LOOKUP_DIRECTORY) {
1037 if (!inode->i_op || !inode->i_op->lookup)
1043 nd->last_type = LAST_NORM;
1044 if (this.name[0] != '.')
1047 nd->last_type = LAST_DOT;
1048 else if (this.len == 2 && this.name[1] == '.')
1049 nd->last_type = LAST_DOTDOT;
1054 * We bypassed the ordinary revalidation routines.
1055 * We may need to check the cached dentry for staleness.
1057 if (nd->path.dentry && nd->path.dentry->d_sb &&
1058 (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) {
1060 /* Note: we do not d_invalidate() */
1061 if (!nd->path.dentry->d_op->d_revalidate(
1062 nd->path.dentry, nd))
1068 path_put_conditional(&next, nd);
1071 path_put(&nd->path);
1076 static int path_walk(const char *name, struct nameidata *nd)
1078 current->total_link_count = 0;
1079 return link_path_walk(name, nd);
1083 * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
1084 * everything is done. Returns 0 and drops input nd, if lookup failed;
1086 static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
1088 if (path_walk(name, nd))
1089 return 0; /* something went wrong... */
1091 if (!nd->path.dentry->d_inode ||
1092 S_ISDIR(nd->path.dentry->d_inode->i_mode)) {
1093 struct path old_path = nd->path;
1094 struct qstr last = nd->last;
1095 int last_type = nd->last_type;
1096 struct fs_struct *fs = current->fs;
1099 * NAME was not found in alternate root or it's a directory.
1100 * Try to find it in the normal root:
1102 nd->last_type = LAST_ROOT;
1103 read_lock(&fs->lock);
1104 nd->path = fs->root;
1105 path_get(&fs->root);
1106 read_unlock(&fs->lock);
1107 if (path_walk(name, nd) == 0) {
1108 if (nd->path.dentry->d_inode) {
1109 path_put(&old_path);
1112 path_put(&nd->path);
1114 nd->path = old_path;
1116 nd->last_type = last_type;
1121 void set_fs_altroot(void)
1123 char *emul = __emul_prefix();
1124 struct nameidata nd;
1125 struct path path = {}, old_path;
1127 struct fs_struct *fs = current->fs;
1131 err = path_lookup(emul, LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOALT, &nd);
1135 write_lock(&fs->lock);
1136 old_path = fs->altroot;
1138 write_unlock(&fs->lock);
1139 if (old_path.dentry)
1140 path_put(&old_path);
1143 /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
1144 static int do_path_lookup(int dfd, const char *name,
1145 unsigned int flags, struct nameidata *nd)
1150 struct fs_struct *fs = current->fs;
1152 nd->last_type = LAST_ROOT; /* if there are only slashes... */
1157 read_lock(&fs->lock);
1158 if (fs->altroot.dentry && !(nd->flags & LOOKUP_NOALT)) {
1159 nd->path = fs->altroot;
1160 path_get(&fs->altroot);
1161 read_unlock(&fs->lock);
1162 if (__emul_lookup_dentry(name,nd))
1163 goto out; /* found in altroot */
1164 read_lock(&fs->lock);
1166 nd->path = fs->root;
1167 path_get(&fs->root);
1168 read_unlock(&fs->lock);
1169 } else if (dfd == AT_FDCWD) {
1170 read_lock(&fs->lock);
1173 read_unlock(&fs->lock);
1175 struct dentry *dentry;
1177 file = fget_light(dfd, &fput_needed);
1182 dentry = file->f_path.dentry;
1185 if (!S_ISDIR(dentry->d_inode->i_mode))
1188 retval = file_permission(file, MAY_EXEC);
1192 nd->path = file->f_path;
1193 path_get(&file->f_path);
1195 fput_light(file, fput_needed);
1198 retval = path_walk(name, nd);
1200 if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
1201 nd->path.dentry->d_inode))
1202 audit_inode(name, nd->path.dentry);
1207 fput_light(file, fput_needed);
1211 int path_lookup(const char *name, unsigned int flags,
1212 struct nameidata *nd)
1214 return do_path_lookup(AT_FDCWD, name, flags, nd);
1218 * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
1219 * @dentry: pointer to dentry of the base directory
1220 * @mnt: pointer to vfs mount of the base directory
1221 * @name: pointer to file name
1222 * @flags: lookup flags
1223 * @nd: pointer to nameidata
1225 int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
1226 const char *name, unsigned int flags,
1227 struct nameidata *nd)
1231 /* same as do_path_lookup */
1232 nd->last_type = LAST_ROOT;
1236 nd->path.dentry = dentry;
1238 path_get(&nd->path);
1240 retval = path_walk(name, nd);
1241 if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry &&
1242 nd->path.dentry->d_inode))
1243 audit_inode(name, nd->path.dentry);
1249 static int __path_lookup_intent_open(int dfd, const char *name,
1250 unsigned int lookup_flags, struct nameidata *nd,
1251 int open_flags, int create_mode)
1253 struct file *filp = get_empty_filp();
1258 nd->intent.open.file = filp;
1259 nd->intent.open.flags = open_flags;
1260 nd->intent.open.create_mode = create_mode;
1261 err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd);
1262 if (IS_ERR(nd->intent.open.file)) {
1264 err = PTR_ERR(nd->intent.open.file);
1265 path_put(&nd->path);
1267 } else if (err != 0)
1268 release_open_intent(nd);
1273 * path_lookup_open - lookup a file path with open intent
1274 * @dfd: the directory to use as base, or AT_FDCWD
1275 * @name: pointer to file name
1276 * @lookup_flags: lookup intent flags
1277 * @nd: pointer to nameidata
1278 * @open_flags: open intent flags
1280 int path_lookup_open(int dfd, const char *name, unsigned int lookup_flags,
1281 struct nameidata *nd, int open_flags)
1283 return __path_lookup_intent_open(dfd, name, lookup_flags, nd,
1288 * path_lookup_create - lookup a file path with open + create intent
1289 * @dfd: the directory to use as base, or AT_FDCWD
1290 * @name: pointer to file name
1291 * @lookup_flags: lookup intent flags
1292 * @nd: pointer to nameidata
1293 * @open_flags: open intent flags
1294 * @create_mode: create intent flags
1296 static int path_lookup_create(int dfd, const char *name,
1297 unsigned int lookup_flags, struct nameidata *nd,
1298 int open_flags, int create_mode)
1300 return __path_lookup_intent_open(dfd, name, lookup_flags|LOOKUP_CREATE,
1301 nd, open_flags, create_mode);
1304 int __user_path_lookup_open(const char __user *name, unsigned int lookup_flags,
1305 struct nameidata *nd, int open_flags)
1307 char *tmp = getname(name);
1308 int err = PTR_ERR(tmp);
1311 err = __path_lookup_intent_open(AT_FDCWD, tmp, lookup_flags, nd, open_flags, 0);
1317 static struct dentry *__lookup_hash(struct qstr *name,
1318 struct dentry *base, struct nameidata *nd)
1320 struct dentry *dentry;
1321 struct inode *inode;
1324 inode = base->d_inode;
1327 * See if the low-level filesystem might want
1328 * to use its own hash..
1330 if (base->d_op && base->d_op->d_hash) {
1331 err = base->d_op->d_hash(base, name);
1332 dentry = ERR_PTR(err);
1337 dentry = cached_lookup(base, name, nd);
1341 /* Don't create child dentry for a dead directory. */
1342 dentry = ERR_PTR(-ENOENT);
1343 if (IS_DEADDIR(inode))
1346 new = d_alloc(base, name);
1347 dentry = ERR_PTR(-ENOMEM);
1350 dentry = inode->i_op->lookup(inode, new, nd);
1361 * Restricted form of lookup. Doesn't follow links, single-component only,
1362 * needs parent already locked. Doesn't follow mounts.
1365 static struct dentry *lookup_hash(struct nameidata *nd)
1369 err = permission(nd->path.dentry->d_inode, MAY_EXEC, nd);
1371 return ERR_PTR(err);
1372 return __lookup_hash(&nd->last, nd->path.dentry, nd);
1375 static int __lookup_one_len(const char *name, struct qstr *this,
1376 struct dentry *base, int len)
1386 hash = init_name_hash();
1388 c = *(const unsigned char *)name++;
1389 if (c == '/' || c == '\0')
1391 hash = partial_name_hash(c, hash);
1393 this->hash = end_name_hash(hash);
1398 * lookup_one_len - filesystem helper to lookup single pathname component
1399 * @name: pathname component to lookup
1400 * @base: base directory to lookup from
1401 * @len: maximum length @len should be interpreted to
1403 * Note that this routine is purely a helper for filesystem usage and should
1404 * not be called by generic code. Also note that by using this function the
1405 * nameidata argument is passed to the filesystem methods and a filesystem
1406 * using this helper needs to be prepared for that.
1408 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
1413 err = __lookup_one_len(name, &this, base, len);
1415 return ERR_PTR(err);
1417 err = permission(base->d_inode, MAY_EXEC, NULL);
1419 return ERR_PTR(err);
1420 return __lookup_hash(&this, base, NULL);
1424 * lookup_one_noperm - bad hack for sysfs
1425 * @name: pathname component to lookup
1426 * @base: base directory to lookup from
1428 * This is a variant of lookup_one_len that doesn't perform any permission
1429 * checks. It's a horrible hack to work around the braindead sysfs
1430 * architecture and should not be used anywhere else.
1432 * DON'T USE THIS FUNCTION EVER, thanks.
1434 struct dentry *lookup_one_noperm(const char *name, struct dentry *base)
1439 err = __lookup_one_len(name, &this, base, strlen(name));
1441 return ERR_PTR(err);
1442 return __lookup_hash(&this, base, NULL);
1445 int __user_walk_fd(int dfd, const char __user *name, unsigned flags,
1446 struct nameidata *nd)
1448 char *tmp = getname(name);
1449 int err = PTR_ERR(tmp);
1452 err = do_path_lookup(dfd, tmp, flags, nd);
1458 int __user_walk(const char __user *name, unsigned flags, struct nameidata *nd)
1460 return __user_walk_fd(AT_FDCWD, name, flags, nd);
1464 * It's inline, so penalty for filesystems that don't use sticky bit is
1467 static inline int check_sticky(struct inode *dir, struct inode *inode)
1469 if (!(dir->i_mode & S_ISVTX))
1471 if (inode->i_uid == current->fsuid)
1473 if (dir->i_uid == current->fsuid)
1475 return !capable(CAP_FOWNER);
1479 * Check whether we can remove a link victim from directory dir, check
1480 * whether the type of victim is right.
1481 * 1. We can't do it if dir is read-only (done in permission())
1482 * 2. We should have write and exec permissions on dir
1483 * 3. We can't remove anything from append-only dir
1484 * 4. We can't do anything with immutable dir (done in permission())
1485 * 5. If the sticky bit on dir is set we should either
1486 * a. be owner of dir, or
1487 * b. be owner of victim, or
1488 * c. have CAP_FOWNER capability
1489 * 6. If the victim is append-only or immutable we can't do antyhing with
1490 * links pointing to it.
1491 * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR.
1492 * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR.
1493 * 9. We can't remove a root or mountpoint.
1494 * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
1495 * nfs_async_unlink().
1497 static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
1501 if (!victim->d_inode)
1504 BUG_ON(victim->d_parent->d_inode != dir);
1505 audit_inode_child(victim->d_name.name, victim, dir);
1507 error = permission(dir,MAY_WRITE | MAY_EXEC, NULL);
1512 if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)||
1513 IS_IMMUTABLE(victim->d_inode))
1516 if (!S_ISDIR(victim->d_inode->i_mode))
1518 if (IS_ROOT(victim))
1520 } else if (S_ISDIR(victim->d_inode->i_mode))
1522 if (IS_DEADDIR(dir))
1524 if (victim->d_flags & DCACHE_NFSFS_RENAMED)
1529 /* Check whether we can create an object with dentry child in directory
1531 * 1. We can't do it if child already exists (open has special treatment for
1532 * this case, but since we are inlined it's OK)
1533 * 2. We can't do it if dir is read-only (done in permission())
1534 * 3. We should have write and exec permissions on dir
1535 * 4. We can't do it if dir is immutable (done in permission())
1537 static inline int may_create(struct inode *dir, struct dentry *child,
1538 struct nameidata *nd)
1542 if (IS_DEADDIR(dir))
1544 return permission(dir,MAY_WRITE | MAY_EXEC, nd);
1548 * O_DIRECTORY translates into forcing a directory lookup.
1550 static inline int lookup_flags(unsigned int f)
1552 unsigned long retval = LOOKUP_FOLLOW;
1555 retval &= ~LOOKUP_FOLLOW;
1557 if (f & O_DIRECTORY)
1558 retval |= LOOKUP_DIRECTORY;
1564 * p1 and p2 should be directories on the same fs.
1566 struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
1571 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
1575 mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
1577 for (p = p1; p->d_parent != p; p = p->d_parent) {
1578 if (p->d_parent == p2) {
1579 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT);
1580 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD);
1585 for (p = p2; p->d_parent != p; p = p->d_parent) {
1586 if (p->d_parent == p1) {
1587 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
1588 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
1593 mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
1594 mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
1598 void unlock_rename(struct dentry *p1, struct dentry *p2)
1600 mutex_unlock(&p1->d_inode->i_mutex);
1602 mutex_unlock(&p2->d_inode->i_mutex);
1603 mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex);
1607 int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
1608 struct nameidata *nd)
1610 int error = may_create(dir, dentry, nd);
1615 if (!dir->i_op || !dir->i_op->create)
1616 return -EACCES; /* shouldn't it be ENOSYS? */
1619 error = security_inode_create(dir, dentry, mode);
1623 error = dir->i_op->create(dir, dentry, mode, nd);
1625 fsnotify_create(dir, dentry);
1629 int may_open(struct nameidata *nd, int acc_mode, int flag)
1631 struct dentry *dentry = nd->path.dentry;
1632 struct inode *inode = dentry->d_inode;
1638 if (S_ISLNK(inode->i_mode))
1641 if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE))
1645 * FIFO's, sockets and device files are special: they don't
1646 * actually live on the filesystem itself, and as such you
1647 * can write to them even if the filesystem is read-only.
1649 if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
1651 } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) {
1652 if (nd->path.mnt->mnt_flags & MNT_NODEV)
1658 error = vfs_permission(nd, acc_mode);
1662 * An append-only file must be opened in append mode for writing.
1664 if (IS_APPEND(inode)) {
1665 if ((flag & FMODE_WRITE) && !(flag & O_APPEND))
1671 /* O_NOATIME can only be set by the owner or superuser */
1672 if (flag & O_NOATIME)
1673 if (!is_owner_or_cap(inode))
1677 * Ensure there are no outstanding leases on the file.
1679 error = break_lease(inode, flag);
1683 if (flag & O_TRUNC) {
1684 error = get_write_access(inode);
1689 * Refuse to truncate files with mandatory locks held on them.
1691 error = locks_verify_locked(inode);
1695 error = do_truncate(dentry, 0,
1696 ATTR_MTIME|ATTR_CTIME|ATTR_OPEN,
1699 put_write_access(inode);
1703 if (flag & FMODE_WRITE)
1710 * Be careful about ever adding any more callers of this
1711 * function. Its flags must be in the namei format, not
1712 * what get passed to sys_open().
1714 static int __open_namei_create(struct nameidata *nd, struct path *path,
1718 struct dentry *dir = nd->path.dentry;
1720 if (!IS_POSIXACL(dir->d_inode))
1721 mode &= ~current->fs->umask;
1722 error = vfs_create(dir->d_inode, path->dentry, mode, nd);
1723 mutex_unlock(&dir->d_inode->i_mutex);
1724 dput(nd->path.dentry);
1725 nd->path.dentry = path->dentry;
1728 /* Don't check for write permission, don't truncate */
1729 return may_open(nd, 0, flag & ~O_TRUNC);
1733 * Note that while the flag value (low two bits) for sys_open means:
1738 * it is changed into
1739 * 00 - no permissions needed
1740 * 01 - read-permission
1741 * 10 - write-permission
1743 * for the internal routines (ie open_namei()/follow_link() etc)
1744 * This is more logical, and also allows the 00 "no perm needed"
1745 * to be used for symlinks (where the permissions are checked
1749 static inline int open_to_namei_flags(int flag)
1751 if ((flag+1) & O_ACCMODE)
1756 static int open_will_write_to_fs(int flag, struct inode *inode)
1759 * We'll never write to the fs underlying
1762 if (special_file(inode->i_mode))
1764 return (flag & O_TRUNC);
1768 * Note that the low bits of the passed in "open_flag"
1769 * are not the same as in the local variable "flag". See
1770 * open_to_namei_flags() for more details.
1772 struct file *do_filp_open(int dfd, const char *pathname,
1773 int open_flag, int mode)
1776 struct nameidata nd;
1777 int acc_mode, error;
1782 int flag = open_to_namei_flags(open_flag);
1784 acc_mode = ACC_MODE(flag);
1786 /* O_TRUNC implies we need access checks for write permissions */
1788 acc_mode |= MAY_WRITE;
1790 /* Allow the LSM permission hook to distinguish append
1791 access from general write access. */
1792 if (flag & O_APPEND)
1793 acc_mode |= MAY_APPEND;
1796 * The simplest case - just a plain lookup.
1798 if (!(flag & O_CREAT)) {
1799 error = path_lookup_open(dfd, pathname, lookup_flags(flag),
1802 return ERR_PTR(error);
1807 * Create - we need to know the parent.
1809 error = path_lookup_create(dfd, pathname, LOOKUP_PARENT,
1812 return ERR_PTR(error);
1815 * We have the parent and last component. First of all, check
1816 * that we are not asked to creat(2) an obvious directory - that
1820 if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len])
1823 dir = nd.path.dentry;
1824 nd.flags &= ~LOOKUP_PARENT;
1825 mutex_lock(&dir->d_inode->i_mutex);
1826 path.dentry = lookup_hash(&nd);
1827 path.mnt = nd.path.mnt;
1830 error = PTR_ERR(path.dentry);
1831 if (IS_ERR(path.dentry)) {
1832 mutex_unlock(&dir->d_inode->i_mutex);
1836 if (IS_ERR(nd.intent.open.file)) {
1837 error = PTR_ERR(nd.intent.open.file);
1838 goto exit_mutex_unlock;
1841 /* Negative dentry, just create the file */
1842 if (!path.dentry->d_inode) {
1844 * This write is needed to ensure that a
1845 * ro->rw transition does not occur between
1846 * the time when the file is created and when
1847 * a permanent write count is taken through
1848 * the 'struct file' in nameidata_to_filp().
1850 error = mnt_want_write(nd.path.mnt);
1852 goto exit_mutex_unlock;
1853 error = __open_namei_create(&nd, &path, flag, mode);
1855 mnt_drop_write(nd.path.mnt);
1858 filp = nameidata_to_filp(&nd, open_flag);
1859 mnt_drop_write(nd.path.mnt);
1864 * It already exists.
1866 mutex_unlock(&dir->d_inode->i_mutex);
1867 audit_inode(pathname, path.dentry);
1873 if (__follow_mount(&path)) {
1875 if (flag & O_NOFOLLOW)
1880 if (!path.dentry->d_inode)
1882 if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link)
1885 path_to_nameidata(&path, &nd);
1887 if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode))
1892 * 1. may_open() truncates a file
1893 * 2. a rw->ro mount transition occurs
1894 * 3. nameidata_to_filp() fails due to
1896 * That would be inconsistent, and should
1897 * be avoided. Taking this mnt write here
1898 * ensures that (2) can not occur.
1900 will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode);
1902 error = mnt_want_write(nd.path.mnt);
1906 error = may_open(&nd, acc_mode, flag);
1909 mnt_drop_write(nd.path.mnt);
1912 filp = nameidata_to_filp(&nd, open_flag);
1914 * It is now safe to drop the mnt write
1915 * because the filp has had a write taken
1919 mnt_drop_write(nd.path.mnt);
1923 mutex_unlock(&dir->d_inode->i_mutex);
1925 path_put_conditional(&path, &nd);
1927 if (!IS_ERR(nd.intent.open.file))
1928 release_open_intent(&nd);
1930 return ERR_PTR(error);
1934 if (flag & O_NOFOLLOW)
1937 * This is subtle. Instead of calling do_follow_link() we do the
1938 * thing by hands. The reason is that this way we have zero link_count
1939 * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT.
1940 * After that we have the parent and last component, i.e.
1941 * we are in the same situation as after the first path_walk().
1942 * Well, almost - if the last component is normal we get its copy
1943 * stored in nd->last.name and we will have to putname() it when we
1944 * are done. Procfs-like symlinks just set LAST_BIND.
1946 nd.flags |= LOOKUP_PARENT;
1947 error = security_inode_follow_link(path.dentry, &nd);
1950 error = __do_follow_link(&path, &nd);
1952 /* Does someone understand code flow here? Or it is only
1953 * me so stupid? Anathema to whoever designed this non-sense
1954 * with "intent.open".
1956 release_open_intent(&nd);
1957 return ERR_PTR(error);
1959 nd.flags &= ~LOOKUP_PARENT;
1960 if (nd.last_type == LAST_BIND)
1963 if (nd.last_type != LAST_NORM)
1965 if (nd.last.name[nd.last.len]) {
1966 __putname(nd.last.name);
1971 __putname(nd.last.name);
1974 dir = nd.path.dentry;
1975 mutex_lock(&dir->d_inode->i_mutex);
1976 path.dentry = lookup_hash(&nd);
1977 path.mnt = nd.path.mnt;
1978 __putname(nd.last.name);
1983 * filp_open - open file and return file pointer
1985 * @filename: path to open
1986 * @flags: open flags as per the open(2) second argument
1987 * @mode: mode for the new file if O_CREAT is set, else ignored
1989 * This is the helper to open a file from kernelspace if you really
1990 * have to. But in generally you should not do this, so please move
1991 * along, nothing to see here..
1993 struct file *filp_open(const char *filename, int flags, int mode)
1995 return do_filp_open(AT_FDCWD, filename, flags, mode);
1997 EXPORT_SYMBOL(filp_open);
2000 * lookup_create - lookup a dentry, creating it if it doesn't exist
2001 * @nd: nameidata info
2002 * @is_dir: directory flag
2004 * Simple function to lookup and return a dentry and create it
2005 * if it doesn't exist. Is SMP-safe.
2007 * Returns with nd->path.dentry->d_inode->i_mutex locked.
2009 struct dentry *lookup_create(struct nameidata *nd, int is_dir)
2011 struct dentry *dentry = ERR_PTR(-EEXIST);
2013 mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
2015 * Yucky last component or no last component at all?
2016 * (foo/., foo/.., /////)
2018 if (nd->last_type != LAST_NORM)
2020 nd->flags &= ~LOOKUP_PARENT;
2021 nd->flags |= LOOKUP_CREATE;
2022 nd->intent.open.flags = O_EXCL;
2025 * Do the final lookup.
2027 dentry = lookup_hash(nd);
2031 if (dentry->d_inode)
2034 * Special case - lookup gave negative, but... we had foo/bar/
2035 * From the vfs_mknod() POV we just have a negative dentry -
2036 * all is fine. Let's be bastards - you had / on the end, you've
2037 * been asking for (non-existent) directory. -ENOENT for you.
2039 if (unlikely(!is_dir && nd->last.name[nd->last.len])) {
2041 dentry = ERR_PTR(-ENOENT);
2046 dentry = ERR_PTR(-EEXIST);
2050 EXPORT_SYMBOL_GPL(lookup_create);
2052 int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
2054 int error = may_create(dir, dentry, NULL);
2059 if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
2062 if (!dir->i_op || !dir->i_op->mknod)
2065 error = devcgroup_inode_mknod(mode, dev);
2069 error = security_inode_mknod(dir, dentry, mode, dev);
2074 error = dir->i_op->mknod(dir, dentry, mode, dev);
2076 fsnotify_create(dir, dentry);
2080 static int may_mknod(mode_t mode)
2082 switch (mode & S_IFMT) {
2088 case 0: /* zero mode translates to S_IFREG */
2097 asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,
2102 struct dentry * dentry;
2103 struct nameidata nd;
2107 tmp = getname(filename);
2109 return PTR_ERR(tmp);
2111 error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
2114 dentry = lookup_create(&nd, 0);
2115 if (IS_ERR(dentry)) {
2116 error = PTR_ERR(dentry);
2119 if (!IS_POSIXACL(nd.path.dentry->d_inode))
2120 mode &= ~current->fs->umask;
2121 error = may_mknod(mode);
2124 error = mnt_want_write(nd.path.mnt);
2127 switch (mode & S_IFMT) {
2128 case 0: case S_IFREG:
2129 error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd);
2131 case S_IFCHR: case S_IFBLK:
2132 error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,
2133 new_decode_dev(dev));
2135 case S_IFIFO: case S_IFSOCK:
2136 error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
2139 mnt_drop_write(nd.path.mnt);
2143 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2151 asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev)
2153 return sys_mknodat(AT_FDCWD, filename, mode, dev);
2156 int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
2158 int error = may_create(dir, dentry, NULL);
2163 if (!dir->i_op || !dir->i_op->mkdir)
2166 mode &= (S_IRWXUGO|S_ISVTX);
2167 error = security_inode_mkdir(dir, dentry, mode);
2172 error = dir->i_op->mkdir(dir, dentry, mode);
2174 fsnotify_mkdir(dir, dentry);
2178 asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode)
2182 struct dentry *dentry;
2183 struct nameidata nd;
2185 tmp = getname(pathname);
2186 error = PTR_ERR(tmp);
2190 error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
2193 dentry = lookup_create(&nd, 1);
2194 error = PTR_ERR(dentry);
2198 if (!IS_POSIXACL(nd.path.dentry->d_inode))
2199 mode &= ~current->fs->umask;
2200 error = mnt_want_write(nd.path.mnt);
2203 error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
2204 mnt_drop_write(nd.path.mnt);
2208 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2216 asmlinkage long sys_mkdir(const char __user *pathname, int mode)
2218 return sys_mkdirat(AT_FDCWD, pathname, mode);
2222 * We try to drop the dentry early: we should have
2223 * a usage count of 2 if we're the only user of this
2224 * dentry, and if that is true (possibly after pruning
2225 * the dcache), then we drop the dentry now.
2227 * A low-level filesystem can, if it choses, legally
2230 * if (!d_unhashed(dentry))
2233 * if it cannot handle the case of removing a directory
2234 * that is still in use by something else..
2236 void dentry_unhash(struct dentry *dentry)
2239 shrink_dcache_parent(dentry);
2240 spin_lock(&dcache_lock);
2241 spin_lock(&dentry->d_lock);
2242 if (atomic_read(&dentry->d_count) == 2)
2244 spin_unlock(&dentry->d_lock);
2245 spin_unlock(&dcache_lock);
2248 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
2250 int error = may_delete(dir, dentry, 1);
2255 if (!dir->i_op || !dir->i_op->rmdir)
2260 mutex_lock(&dentry->d_inode->i_mutex);
2261 dentry_unhash(dentry);
2262 if (d_mountpoint(dentry))
2265 error = security_inode_rmdir(dir, dentry);
2267 error = dir->i_op->rmdir(dir, dentry);
2269 dentry->d_inode->i_flags |= S_DEAD;
2272 mutex_unlock(&dentry->d_inode->i_mutex);
2281 static long do_rmdir(int dfd, const char __user *pathname)
2285 struct dentry *dentry;
2286 struct nameidata nd;
2288 name = getname(pathname);
2290 return PTR_ERR(name);
2292 error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);
2296 switch(nd.last_type) {
2307 mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
2308 dentry = lookup_hash(&nd);
2309 error = PTR_ERR(dentry);
2312 error = mnt_want_write(nd.path.mnt);
2315 error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
2316 mnt_drop_write(nd.path.mnt);
2320 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2328 asmlinkage long sys_rmdir(const char __user *pathname)
2330 return do_rmdir(AT_FDCWD, pathname);
2333 int vfs_unlink(struct inode *dir, struct dentry *dentry)
2335 int error = may_delete(dir, dentry, 0);
2340 if (!dir->i_op || !dir->i_op->unlink)
2345 mutex_lock(&dentry->d_inode->i_mutex);
2346 if (d_mountpoint(dentry))
2349 error = security_inode_unlink(dir, dentry);
2351 error = dir->i_op->unlink(dir, dentry);
2353 mutex_unlock(&dentry->d_inode->i_mutex);
2355 /* We don't d_delete() NFS sillyrenamed files--they still exist. */
2356 if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) {
2357 fsnotify_link_count(dentry->d_inode);
2365 * Make sure that the actual truncation of the file will occur outside its
2366 * directory's i_mutex. Truncate can take a long time if there is a lot of
2367 * writeout happening, and we don't want to prevent access to the directory
2368 * while waiting on the I/O.
2370 static long do_unlinkat(int dfd, const char __user *pathname)
2374 struct dentry *dentry;
2375 struct nameidata nd;
2376 struct inode *inode = NULL;
2378 name = getname(pathname);
2380 return PTR_ERR(name);
2382 error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);
2386 if (nd.last_type != LAST_NORM)
2388 mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
2389 dentry = lookup_hash(&nd);
2390 error = PTR_ERR(dentry);
2391 if (!IS_ERR(dentry)) {
2392 /* Why not before? Because we want correct error value */
2393 if (nd.last.name[nd.last.len])
2395 inode = dentry->d_inode;
2397 atomic_inc(&inode->i_count);
2398 error = mnt_want_write(nd.path.mnt);
2401 error = vfs_unlink(nd.path.dentry->d_inode, dentry);
2402 mnt_drop_write(nd.path.mnt);
2406 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2408 iput(inode); /* truncate the inode here */
2416 error = !dentry->d_inode ? -ENOENT :
2417 S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
2421 asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag)
2423 if ((flag & ~AT_REMOVEDIR) != 0)
2426 if (flag & AT_REMOVEDIR)
2427 return do_rmdir(dfd, pathname);
2429 return do_unlinkat(dfd, pathname);
2432 asmlinkage long sys_unlink(const char __user *pathname)
2434 return do_unlinkat(AT_FDCWD, pathname);
2437 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
2439 int error = may_create(dir, dentry, NULL);
2444 if (!dir->i_op || !dir->i_op->symlink)
2447 error = security_inode_symlink(dir, dentry, oldname);
2452 error = dir->i_op->symlink(dir, dentry, oldname);
2454 fsnotify_create(dir, dentry);
2458 asmlinkage long sys_symlinkat(const char __user *oldname,
2459 int newdfd, const char __user *newname)
2464 struct dentry *dentry;
2465 struct nameidata nd;
2467 from = getname(oldname);
2469 return PTR_ERR(from);
2470 to = getname(newname);
2471 error = PTR_ERR(to);
2475 error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
2478 dentry = lookup_create(&nd, 0);
2479 error = PTR_ERR(dentry);
2483 error = mnt_want_write(nd.path.mnt);
2486 error = vfs_symlink(nd.path.dentry->d_inode, dentry, from);
2487 mnt_drop_write(nd.path.mnt);
2491 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2500 asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname)
2502 return sys_symlinkat(oldname, AT_FDCWD, newname);
2505 int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
2507 struct inode *inode = old_dentry->d_inode;
2513 error = may_create(dir, new_dentry, NULL);
2517 if (dir->i_sb != inode->i_sb)
2521 * A link to an append-only or immutable file cannot be created.
2523 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
2525 if (!dir->i_op || !dir->i_op->link)
2527 if (S_ISDIR(inode->i_mode))
2530 error = security_inode_link(old_dentry, dir, new_dentry);
2534 mutex_lock(&inode->i_mutex);
2536 error = dir->i_op->link(old_dentry, dir, new_dentry);
2537 mutex_unlock(&inode->i_mutex);
2539 fsnotify_link(dir, inode, new_dentry);
2544 * Hardlinks are often used in delicate situations. We avoid
2545 * security-related surprises by not following symlinks on the
2548 * We don't follow them on the oldname either to be compatible
2549 * with linux 2.0, and to avoid hard-linking to directories
2550 * and other special files. --ADM
2552 asmlinkage long sys_linkat(int olddfd, const char __user *oldname,
2553 int newdfd, const char __user *newname,
2556 struct dentry *new_dentry;
2557 struct nameidata nd, old_nd;
2561 if ((flags & ~AT_SYMLINK_FOLLOW) != 0)
2564 to = getname(newname);
2568 error = __user_walk_fd(olddfd, oldname,
2569 flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,
2573 error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
2577 if (old_nd.path.mnt != nd.path.mnt)
2579 new_dentry = lookup_create(&nd, 0);
2580 error = PTR_ERR(new_dentry);
2581 if (IS_ERR(new_dentry))
2583 error = mnt_want_write(nd.path.mnt);
2586 error = vfs_link(old_nd.path.dentry, nd.path.dentry->d_inode, new_dentry);
2587 mnt_drop_write(nd.path.mnt);
2591 mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
2595 path_put(&old_nd.path);
2602 asmlinkage long sys_link(const char __user *oldname, const char __user *newname)
2604 return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
2608 * The worst of all namespace operations - renaming directory. "Perverted"
2609 * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
2611 * a) we can get into loop creation. Check is done in is_subdir().
2612 * b) race potential - two innocent renames can create a loop together.
2613 * That's where 4.4 screws up. Current fix: serialization on
2614 * sb->s_vfs_rename_mutex. We might be more accurate, but that's another
2616 * c) we have to lock _three_ objects - parents and victim (if it exists).
2617 * And that - after we got ->i_mutex on parents (until then we don't know
2618 * whether the target exists). Solution: try to be smart with locking
2619 * order for inodes. We rely on the fact that tree topology may change
2620 * only under ->s_vfs_rename_mutex _and_ that parent of the object we
2621 * move will be locked. Thus we can rank directories by the tree
2622 * (ancestors first) and rank all non-directories after them.
2623 * That works since everybody except rename does "lock parent, lookup,
2624 * lock child" and rename is under ->s_vfs_rename_mutex.
2625 * HOWEVER, it relies on the assumption that any object with ->lookup()
2626 * has no more than 1 dentry. If "hybrid" objects will ever appear,
2627 * we'd better make sure that there's no link(2) for them.
2628 * d) some filesystems don't support opened-but-unlinked directories,
2629 * either because of layout or because they are not ready to deal with
2630 * all cases correctly. The latter will be fixed (taking this sort of
2631 * stuff into VFS), but the former is not going away. Solution: the same
2632 * trick as in rmdir().
2633 * e) conversion from fhandle to dentry may come in the wrong moment - when
2634 * we are removing the target. Solution: we will have to grab ->i_mutex
2635 * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on
2636 * ->i_mutex on parents, which works but leads to some truely excessive
2639 static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
2640 struct inode *new_dir, struct dentry *new_dentry)
2643 struct inode *target;
2646 * If we are going to change the parent - check write permissions,
2647 * we'll need to flip '..'.
2649 if (new_dir != old_dir) {
2650 error = permission(old_dentry->d_inode, MAY_WRITE, NULL);
2655 error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
2659 target = new_dentry->d_inode;
2661 mutex_lock(&target->i_mutex);
2662 dentry_unhash(new_dentry);
2664 if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
2667 error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
2670 target->i_flags |= S_DEAD;
2671 mutex_unlock(&target->i_mutex);
2672 if (d_unhashed(new_dentry))
2673 d_rehash(new_dentry);
2677 if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
2678 d_move(old_dentry,new_dentry);
2682 static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
2683 struct inode *new_dir, struct dentry *new_dentry)
2685 struct inode *target;
2688 error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
2693 target = new_dentry->d_inode;
2695 mutex_lock(&target->i_mutex);
2696 if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
2699 error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
2701 if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
2702 d_move(old_dentry, new_dentry);
2705 mutex_unlock(&target->i_mutex);
2710 int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
2711 struct inode *new_dir, struct dentry *new_dentry)
2714 int is_dir = S_ISDIR(old_dentry->d_inode->i_mode);
2715 const char *old_name;
2717 if (old_dentry->d_inode == new_dentry->d_inode)
2720 error = may_delete(old_dir, old_dentry, is_dir);
2724 if (!new_dentry->d_inode)
2725 error = may_create(new_dir, new_dentry, NULL);
2727 error = may_delete(new_dir, new_dentry, is_dir);
2731 if (!old_dir->i_op || !old_dir->i_op->rename)
2734 DQUOT_INIT(old_dir);
2735 DQUOT_INIT(new_dir);
2737 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
2740 error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
2742 error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
2744 const char *new_name = old_dentry->d_name.name;
2745 fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir,
2746 new_dentry->d_inode, old_dentry);
2748 fsnotify_oldname_free(old_name);
2753 static int do_rename(int olddfd, const char *oldname,
2754 int newdfd, const char *newname)
2757 struct dentry * old_dir, * new_dir;
2758 struct dentry * old_dentry, *new_dentry;
2759 struct dentry * trap;
2760 struct nameidata oldnd, newnd;
2762 error = do_path_lookup(olddfd, oldname, LOOKUP_PARENT, &oldnd);
2766 error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd);
2771 if (oldnd.path.mnt != newnd.path.mnt)
2774 old_dir = oldnd.path.dentry;
2776 if (oldnd.last_type != LAST_NORM)
2779 new_dir = newnd.path.dentry;
2780 if (newnd.last_type != LAST_NORM)
2783 trap = lock_rename(new_dir, old_dir);
2785 old_dentry = lookup_hash(&oldnd);
2786 error = PTR_ERR(old_dentry);
2787 if (IS_ERR(old_dentry))
2789 /* source must exist */
2791 if (!old_dentry->d_inode)
2793 /* unless the source is a directory trailing slashes give -ENOTDIR */
2794 if (!S_ISDIR(old_dentry->d_inode->i_mode)) {
2796 if (oldnd.last.name[oldnd.last.len])
2798 if (newnd.last.name[newnd.last.len])
2801 /* source should not be ancestor of target */
2803 if (old_dentry == trap)
2805 new_dentry = lookup_hash(&newnd);
2806 error = PTR_ERR(new_dentry);
2807 if (IS_ERR(new_dentry))
2809 /* target should not be an ancestor of source */
2811 if (new_dentry == trap)
2814 error = mnt_want_write(oldnd.path.mnt);
2817 error = vfs_rename(old_dir->d_inode, old_dentry,
2818 new_dir->d_inode, new_dentry);
2819 mnt_drop_write(oldnd.path.mnt);
2825 unlock_rename(new_dir, old_dir);
2827 path_put(&newnd.path);
2829 path_put(&oldnd.path);
2834 asmlinkage long sys_renameat(int olddfd, const char __user *oldname,
2835 int newdfd, const char __user *newname)
2841 from = getname(oldname);
2843 return PTR_ERR(from);
2844 to = getname(newname);
2845 error = PTR_ERR(to);
2847 error = do_rename(olddfd, from, newdfd, to);
2854 asmlinkage long sys_rename(const char __user *oldname, const char __user *newname)
2856 return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
2859 int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link)
2863 len = PTR_ERR(link);
2868 if (len > (unsigned) buflen)
2870 if (copy_to_user(buffer, link, len))
2877 * A helper for ->readlink(). This should be used *ONLY* for symlinks that
2878 * have ->follow_link() touching nd only in nd_set_link(). Using (or not
2879 * using) it for any given inode is up to filesystem.
2881 int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
2883 struct nameidata nd;
2888 cookie = dentry->d_inode->i_op->follow_link(dentry, &nd);
2890 return PTR_ERR(cookie);
2892 res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
2893 if (dentry->d_inode->i_op->put_link)
2894 dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
2898 int vfs_follow_link(struct nameidata *nd, const char *link)
2900 return __vfs_follow_link(nd, link);
2903 /* get the link contents into pagecache */
2904 static char *page_getlink(struct dentry * dentry, struct page **ppage)
2907 struct address_space *mapping = dentry->d_inode->i_mapping;
2908 page = read_mapping_page(mapping, 0, NULL);
2915 int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
2917 struct page *page = NULL;
2918 char *s = page_getlink(dentry, &page);
2919 int res = vfs_readlink(dentry,buffer,buflen,s);
2922 page_cache_release(page);
2927 void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
2929 struct page *page = NULL;
2930 nd_set_link(nd, page_getlink(dentry, &page));
2934 void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
2936 struct page *page = cookie;
2940 page_cache_release(page);
2944 int __page_symlink(struct inode *inode, const char *symname, int len,
2947 struct address_space *mapping = inode->i_mapping;
2954 err = pagecache_write_begin(NULL, mapping, 0, len-1,
2955 AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata);
2959 kaddr = kmap_atomic(page, KM_USER0);
2960 memcpy(kaddr, symname, len-1);
2961 kunmap_atomic(kaddr, KM_USER0);
2963 err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
2970 mark_inode_dirty(inode);
2976 int page_symlink(struct inode *inode, const char *symname, int len)
2978 return __page_symlink(inode, symname, len,
2979 mapping_gfp_mask(inode->i_mapping));
2982 const struct inode_operations page_symlink_inode_operations = {
2983 .readlink = generic_readlink,
2984 .follow_link = page_follow_link_light,
2985 .put_link = page_put_link,
2988 EXPORT_SYMBOL(__user_walk);
2989 EXPORT_SYMBOL(__user_walk_fd);
2990 EXPORT_SYMBOL(follow_down);
2991 EXPORT_SYMBOL(follow_up);
2992 EXPORT_SYMBOL(get_write_access); /* binfmt_aout */
2993 EXPORT_SYMBOL(getname);
2994 EXPORT_SYMBOL(lock_rename);
2995 EXPORT_SYMBOL(lookup_one_len);
2996 EXPORT_SYMBOL(page_follow_link_light);
2997 EXPORT_SYMBOL(page_put_link);
2998 EXPORT_SYMBOL(page_readlink);
2999 EXPORT_SYMBOL(__page_symlink);
3000 EXPORT_SYMBOL(page_symlink);
3001 EXPORT_SYMBOL(page_symlink_inode_operations);
3002 EXPORT_SYMBOL(path_lookup);
3003 EXPORT_SYMBOL(vfs_path_lookup);
3004 EXPORT_SYMBOL(permission);
3005 EXPORT_SYMBOL(vfs_permission);
3006 EXPORT_SYMBOL(file_permission);
3007 EXPORT_SYMBOL(unlock_rename);
3008 EXPORT_SYMBOL(vfs_create);
3009 EXPORT_SYMBOL(vfs_follow_link);
3010 EXPORT_SYMBOL(vfs_link);
3011 EXPORT_SYMBOL(vfs_mkdir);
3012 EXPORT_SYMBOL(vfs_mknod);
3013 EXPORT_SYMBOL(generic_permission);
3014 EXPORT_SYMBOL(vfs_readlink);
3015 EXPORT_SYMBOL(vfs_rename);
3016 EXPORT_SYMBOL(vfs_rmdir);
3017 EXPORT_SYMBOL(vfs_symlink);
3018 EXPORT_SYMBOL(vfs_unlink);
3019 EXPORT_SYMBOL(dentry_unhash);
3020 EXPORT_SYMBOL(generic_readlink);