#include <linux/proc_fs.h>
#include <linux/vserver/inode.h>
#include <linux/vserver/debug.h>
-
#include <asm/namei.h>
#include <asm/uaccess.h>
result = ERR_PTR(retval);
}
}
- if (unlikely(current->audit_context) && !IS_ERR(result) && result)
- audit_getname(result);
+ audit_getname(result);
return result;
}
+#ifdef CONFIG_AUDITSYSCALL
+void putname(const char *name)
+{
+ if (unlikely(current->audit_context))
+ audit_putname(name);
+ else
+ __putname(name);
+}
+EXPORT_SYMBOL(putname);
+#endif
+
+
/**
* generic_permission - check for access rights on a Posix-like filesystem
* @inode: inode to check access rights for
return PTR_ERR(link);
}
-static inline int __do_follow_link(struct dentry *dentry, struct nameidata *nd)
+struct path {
+ struct vfsmount *mnt;
+ struct dentry *dentry;
+};
+
+static inline int __do_follow_link(struct path *path, struct nameidata *nd)
{
int error;
+ struct dentry *dentry = path->dentry;
- touch_atime(nd->mnt, dentry);
+ touch_atime(path->mnt, dentry);
nd_set_link(nd, NULL);
+
+ if (path->mnt == nd->mnt)
+ mntget(path->mnt);
error = dentry->d_inode->i_op->follow_link(dentry, nd);
if (!error) {
char *s = nd_get_link(nd);
if (dentry->d_inode->i_op->put_link)
dentry->d_inode->i_op->put_link(dentry, nd);
}
+ dput(dentry);
+ mntput(path->mnt);
return error;
}
* Without that kind of total limit, nasty chains of consecutive
* symlinks can cause almost arbitrarily long lookups.
*/
-static inline int do_follow_link(struct dentry *dentry, struct nameidata *nd)
+static inline int do_follow_link(struct path *path, struct nameidata *nd)
{
int err = -ELOOP;
if (current->link_count >= MAX_NESTED_LINKS)
goto loop;
BUG_ON(nd->depth >= MAX_NESTED_LINKS);
cond_resched();
- err = security_inode_follow_link(dentry, nd);
+ err = security_inode_follow_link(path->dentry, nd);
if (err)
goto loop;
current->link_count++;
current->total_link_count++;
nd->depth++;
- err = __do_follow_link(dentry, nd);
+ err = __do_follow_link(path, nd);
current->link_count--;
nd->depth--;
return err;
loop:
+ dput(path->dentry);
+ if (path->mnt != nd->mnt)
+ mntput(path->mnt);
path_release(nd);
return err;
}
/* no need for dcache_lock, as serialization is taken care in
* namespace.c
*/
-static int follow_mount(struct vfsmount **mnt, struct dentry **dentry)
+static int __follow_mount(struct path *path)
{
int res = 0;
+ while (d_mountpoint(path->dentry)) {
+ struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry);
+ if (!mounted)
+ break;
+ dput(path->dentry);
+ if (res)
+ mntput(path->mnt);
+ path->mnt = mounted;
+ path->dentry = dget(mounted->mnt_root);
+ res = 1;
+ }
+ return res;
+}
+
+static void follow_mount(struct vfsmount **mnt, struct dentry **dentry)
+{
while (d_mountpoint(*dentry)) {
struct vfsmount *mounted = lookup_mnt(*mnt, *dentry);
if (!mounted)
break;
+ dput(*dentry);
mntput(*mnt);
*mnt = mounted;
- dput(*dentry);
*dentry = dget(mounted->mnt_root);
- res = 1;
}
- return res;
}
/* no need for dcache_lock, as serialization is taken care in
* namespace.c
*/
-static inline int __follow_down(struct vfsmount **mnt, struct dentry **dentry)
+int follow_down(struct vfsmount **mnt, struct dentry **dentry)
{
struct vfsmount *mounted;
mounted = lookup_mnt(*mnt, *dentry);
if (mounted) {
+ dput(*dentry);
mntput(*mnt);
*mnt = mounted;
- dput(*dentry);
*dentry = dget(mounted->mnt_root);
return 1;
}
return 0;
}
-int follow_down(struct vfsmount **mnt, struct dentry **dentry)
-{
- return __follow_down(mnt,dentry);
-}
-
-static inline void follow_dotdot(struct vfsmount **mnt, struct dentry **dentry)
+static inline void follow_dotdot(struct nameidata *nd)
{
while(1) {
struct vfsmount *parent;
- struct dentry *old = *dentry;
+ struct dentry *old = nd->dentry;
read_lock(¤t->fs->lock);
- if (*dentry == current->fs->root &&
- *mnt == current->fs->rootmnt) {
+ if (nd->dentry == current->fs->root &&
+ nd->mnt == current->fs->rootmnt) {
read_unlock(¤t->fs->lock);
+ /* for sane '/' avoid follow_mount() */
return;
}
read_unlock(¤t->fs->lock);
spin_lock(&dcache_lock);
- if (*dentry != (*mnt)->mnt_root) {
- *dentry = dget((*dentry)->d_parent);
+ if (nd->dentry != nd->mnt->mnt_root) {
+ nd->dentry = dget(nd->dentry->d_parent);
spin_unlock(&dcache_lock);
dput(old);
break;
}
spin_unlock(&dcache_lock);
spin_lock(&vfsmount_lock);
- parent = (*mnt)->mnt_parent;
- if (parent == *mnt) {
+ parent = nd->mnt->mnt_parent;
+ if (parent == nd->mnt) {
spin_unlock(&vfsmount_lock);
break;
}
mntget(parent);
- *dentry = dget((*mnt)->mnt_mountpoint);
+ nd->dentry = dget(nd->mnt->mnt_mountpoint);
spin_unlock(&vfsmount_lock);
dput(old);
- mntput(*mnt);
- *mnt = parent;
+ mntput(nd->mnt);
+ nd->mnt = parent;
}
- follow_mount(mnt, dentry);
+ follow_mount(&nd->mnt, &nd->dentry);
}
-struct path {
- struct vfsmount *mnt;
- struct dentry *dentry;
-};
-
/*
* It's more convoluted than I'd like it to be, but... it's still fairly
* small and for now I'd prefer to have fast path as straight as possible.
done:
path->mnt = mnt;
path->dentry = dentry;
+ __follow_mount(path);
return 0;
hidden:
vxwprintk(1, "xid=%d did lookup hidden %p[#%d,%lu] »%s«.",
/*
* Name resolution.
+ * This is the basic name resolution function, turning a pathname into
+ * the final dentry. We expect 'base' to be positive and a directory.
*
- * This is the basic name resolution function, turning a pathname
- * into the final dentry.
- *
- * We expect 'base' to be positive and a directory.
+ * Returns 0 and nd will have valid dentry and mnt on success.
+ * Returns error and drops reference to input namei data on failure.
*/
-int fastcall link_path_walk(const char * name, struct nameidata *nd)
+static fastcall int __link_path_walk(const char * name, struct nameidata *nd)
{
struct path next;
struct inode *inode;
case 2:
if (this.name[1] != '.')
break;
- follow_dotdot(&nd->mnt, &nd->dentry);
+ follow_dotdot(nd);
inode = nd->dentry->d_inode;
/* fallthrough */
case 1:
err = do_lookup(nd, &this, &next);
if (err)
break;
- /* Check mountpoints.. */
- follow_mount(&next.mnt, &next.dentry);
err = -ENOENT;
inode = next.dentry->d_inode;
goto out_dput;
if (inode->i_op->follow_link) {
- mntget(next.mnt);
- err = do_follow_link(next.dentry, nd);
- dput(next.dentry);
- mntput(next.mnt);
+ err = do_follow_link(&next, nd);
if (err)
goto return_err;
err = -ENOENT;
break;
} else {
dput(nd->dentry);
+ if (nd->mnt != next.mnt)
+ mntput(nd->mnt);
nd->mnt = next.mnt;
nd->dentry = next.dentry;
}
case 2:
if (this.name[1] != '.')
break;
- follow_dotdot(&nd->mnt, &nd->dentry);
+ follow_dotdot(nd);
inode = nd->dentry->d_inode;
/* fallthrough */
case 1:
err = do_lookup(nd, &this, &next);
if (err)
break;
- follow_mount(&next.mnt, &next.dentry);
inode = next.dentry->d_inode;
if ((lookup_flags & LOOKUP_FOLLOW)
&& inode && inode->i_op && inode->i_op->follow_link) {
- mntget(next.mnt);
- err = do_follow_link(next.dentry, nd);
- dput(next.dentry);
- mntput(next.mnt);
+ err = do_follow_link(&next, nd);
if (err)
goto return_err;
inode = nd->dentry->d_inode;
} else {
dput(nd->dentry);
+ if (nd->mnt != next.mnt)
+ mntput(nd->mnt);
nd->mnt = next.mnt;
nd->dentry = next.dentry;
}
return 0;
out_dput:
dput(next.dentry);
+ if (nd->mnt != next.mnt)
+ mntput(next.mnt);
break;
}
path_release(nd);
return err;
}
+/*
+ * Wrapper to retry pathname resolution whenever the underlying
+ * file system returns an ESTALE.
+ *
+ * Retry the whole path once, forcing real lookup requests
+ * instead of relying on the dcache.
+ */
+int fastcall link_path_walk(const char *name, struct nameidata *nd)
+{
+ struct nameidata save = *nd;
+ int result;
+
+ /* make sure the stuff we saved doesn't go away */
+ dget(save.dentry);
+ mntget(save.mnt);
+
+ result = __link_path_walk(name, nd);
+ if (result == -ESTALE) {
+ *nd = save;
+ dget(nd->dentry);
+ mntget(nd->mnt);
+ nd->flags |= LOOKUP_REVAL;
+ result = __link_path_walk(name, nd);
+ }
+
+ dput(save.dentry);
+ mntput(save.mnt);
+
+ return result;
+}
+
int fastcall path_walk(const char * name, struct nameidata *nd)
{
current->total_link_count = 0;
return link_path_walk(name, nd);
}
-/* SMP-safe */
-/* returns 1 if everything is done */
+/*
+ * SMP-safe: Returns 1 and nd will have valid dentry and mnt, if
+ * everything is done. Returns 0 and drops input nd, if lookup failed;
+ */
static int __emul_lookup_dentry(const char *name, struct nameidata *nd)
{
if (path_walk(name, nd))
}
}
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata *nd)
{
- int retval;
+ int retval = 0;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags;
nd->dentry = dget(current->fs->altroot);
read_unlock(¤t->fs->lock);
if (__emul_lookup_dentry(name,nd))
- return 0;
+ goto out; /* found in altroot */
read_lock(¤t->fs->lock);
}
nd->mnt = mntget(current->fs->rootmnt);
read_unlock(¤t->fs->lock);
current->total_link_count = 0;
retval = link_path_walk(name, nd);
+out:
if (unlikely(current->audit_context
&& nd && nd->dentry && nd->dentry->d_inode))
- audit_inode(name,
- nd->dentry->d_inode->i_ino,
- nd->dentry->d_inode->i_rdev);
+ audit_inode(name, nd->dentry->d_inode);
return retval;
}
int open_namei(const char * pathname, int flag, int mode, struct nameidata *nd)
{
int acc_mode, error = 0;
- struct dentry *dentry;
+ struct path path;
struct dentry *dir;
int count = 0;
dir = nd->dentry;
nd->flags &= ~LOOKUP_PARENT;
down(&dir->d_inode->i_sem);
- dentry = __lookup_hash(&nd->last, nd->dentry, nd);
+ path.dentry = __lookup_hash(&nd->last, nd->dentry, nd);
+ path.mnt = nd->mnt;
do_last:
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry)) {
+ error = PTR_ERR(path.dentry);
+ if (IS_ERR(path.dentry)) {
up(&dir->d_inode->i_sem);
goto exit;
}
/* Negative dentry, just create the file */
- if (!dentry->d_inode) {
+ if (!path.dentry->d_inode) {
if (!IS_POSIXACL(dir->d_inode))
mode &= ~current->fs->umask;
- error = vfs_create(dir->d_inode, dentry, mode, nd);
+ error = vfs_create(dir->d_inode, path.dentry, mode, nd);
up(&dir->d_inode->i_sem);
dput(nd->dentry);
- nd->dentry = dentry;
+ nd->dentry = path.dentry;
if (error)
goto exit;
/* Don't check for write permission, don't truncate */
if (flag & O_EXCL)
goto exit_dput;
- if (d_mountpoint(dentry)) {
+ if (__follow_mount(&path)) {
error = -ELOOP;
if (flag & O_NOFOLLOW)
goto exit_dput;
- while (__follow_down(&nd->mnt,&dentry) && d_mountpoint(dentry));
}
error = -ENOENT;
- if (!dentry->d_inode)
+ if (!path.dentry->d_inode)
goto exit_dput;
- if (dentry->d_inode->i_op && dentry->d_inode->i_op->follow_link)
+ if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link)
goto do_link;
dput(nd->dentry);
- nd->dentry = dentry;
+ nd->dentry = path.dentry;
+ if (nd->mnt != path.mnt)
+ mntput(nd->mnt);
+ nd->mnt = path.mnt;
error = -EISDIR;
- if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode))
+ if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode))
goto exit;
ok:
error = may_open(nd, acc_mode, flag);
return 0;
exit_dput:
- dput(dentry);
+ dput(path.dentry);
+ if (nd->mnt != path.mnt)
+ mntput(path.mnt);
exit:
path_release(nd);
return error;
* are done. Procfs-like symlinks just set LAST_BIND.
*/
nd->flags |= LOOKUP_PARENT;
- error = security_inode_follow_link(dentry, nd);
+ error = security_inode_follow_link(path.dentry, nd);
if (error)
goto exit_dput;
- error = __do_follow_link(dentry, nd);
- dput(dentry);
+ error = __do_follow_link(&path, nd);
if (error)
return error;
nd->flags &= ~LOOKUP_PARENT;
- if (nd->last_type == LAST_BIND) {
- dentry = nd->dentry;
+ if (nd->last_type == LAST_BIND)
goto ok;
- }
error = -EISDIR;
if (nd->last_type != LAST_NORM)
goto exit;
}
dir = nd->dentry;
down(&dir->d_inode->i_sem);
- dentry = __lookup_hash(&nd->last, nd->dentry, nd);
+ path.dentry = __lookup_hash(&nd->last, nd->dentry, nd);
+ path.mnt = nd->mnt;
putname(nd->last.name);
goto do_last;
}
fail:
return dentry;
}
+EXPORT_SYMBOL_GPL(lookup_create);
int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
void dentry_unhash(struct dentry *dentry)
{
dget(dentry);
- spin_lock(&dcache_lock);
- switch (atomic_read(&dentry->d_count)) {
- default:
- spin_unlock(&dcache_lock);
+ if (atomic_read(&dentry->d_count))
shrink_dcache_parent(dentry);
- spin_lock(&dcache_lock);
- if (atomic_read(&dentry->d_count) != 2)
- break;
- case 2:
+ spin_lock(&dcache_lock);
+ spin_lock(&dentry->d_lock);
+ if (atomic_read(&dentry->d_count) == 2)
__d_drop(dentry);
- }
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
}
* ->i_sem on parents, which works but leads to some truely excessive
* locking].
*/
-int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry)
+static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
{
int error = 0;
struct inode *target;
return error;
}
-int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry)
+static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
{
struct inode *target;
int error;
git://git.onelab.eu / linux-2.6.git / blobdiff