Commit f5beed75 authored by Al Viro's avatar Al Viro
Browse files

name: shift nameidata down into user_path_walk() 



that avoids having nameidata on stack during the calls of
->rmdir()/->unlink() and *two* of those during the calls
of ->rename().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6a9f40d6

fs/namei.c

+67 −57
Original line number Diff line number Diff line
@@ -2211,9 +2211,13 @@ EXPORT_SYMBOL(user_path_at); 
 *     path-walking is complete.

 */

static struct filename *

user_path_parent(int dfd, const char __user *path, struct nameidata *nd,

user_path_parent(int dfd, const char __user *path,

		 struct path *parent,

		 struct qstr *last,

		 int *type,

		 unsigned int flags)

{

	struct nameidata nd;

	struct filename *s = getname(path);

	int error;
@@ -2223,11 +2227,14 @@ user_path_parent(int dfd, const char __user *path, struct nameidata *nd, 
	if (IS_ERR(s))

		return s;



	error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd);

	error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, &nd);

	if (error) {

		putname(s);

		return ERR_PTR(error);

	}

	*parent = nd.path;

	*last = nd.last;

	*type = nd.last_type;



	return s;

}
@@ -3630,14 +3637,17 @@ static long do_rmdir(int dfd, const char __user *pathname) 
	int error = 0;

	struct filename *name;

	struct dentry *dentry;

	struct nameidata nd;

	struct path path;

	struct qstr last;

	int type;

	unsigned int lookup_flags = 0;

retry:

	name = user_path_parent(dfd, pathname, &nd, lookup_flags);

	name = user_path_parent(dfd, pathname,

				&path, &last, &type, lookup_flags);

	if (IS_ERR(name))

		return PTR_ERR(name);



	switch(nd.last_type) {

	switch (type) {

	case LAST_DOTDOT:

		error = -ENOTEMPTY;

		goto exit1;
@@ -3649,13 +3659,12 @@ static long do_rmdir(int dfd, const char __user *pathname) 
		goto exit1;

	}



	nd.flags &= ~LOOKUP_PARENT;

	error = mnt_want_write(nd.path.mnt);

	error = mnt_want_write(path.mnt);

	if (error)

		goto exit1;



	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);

	mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = __lookup_hash(&last, path.dentry, lookup_flags);

	error = PTR_ERR(dentry);

	if (IS_ERR(dentry))

		goto exit2;
@@ -3663,17 +3672,17 @@ static long do_rmdir(int dfd, const char __user *pathname) 
		error = -ENOENT;

		goto exit3;

	}

	error = security_path_rmdir(&nd.path, dentry);

	error = security_path_rmdir(&path, dentry);

	if (error)

		goto exit3;

	error = vfs_rmdir(nd.path.dentry->d_inode, dentry);

	error = vfs_rmdir(path.dentry->d_inode, dentry);

exit3:

	dput(dentry);

exit2:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	mnt_drop_write(nd.path.mnt);

	mutex_unlock(&path.dentry->d_inode->i_mutex);

	mnt_drop_write(path.mnt);

exit1:

	path_put(&nd.path);

	path_put(&path);

	putname(name);

	if (retry_estale(error, lookup_flags)) {

		lookup_flags |= LOOKUP_REVAL;
@@ -3756,43 +3765,45 @@ static long do_unlinkat(int dfd, const char __user *pathname) 
	int error;

	struct filename *name;

	struct dentry *dentry;

	struct nameidata nd;

	struct path path;

	struct qstr last;

	int type;

	struct inode *inode = NULL;

	struct inode *delegated_inode = NULL;

	unsigned int lookup_flags = 0;

retry:

	name = user_path_parent(dfd, pathname, &nd, lookup_flags);

	name = user_path_parent(dfd, pathname,

				&path, &last, &type, lookup_flags);

	if (IS_ERR(name))

		return PTR_ERR(name);



	error = -EISDIR;

	if (nd.last_type != LAST_NORM)

	if (type != LAST_NORM)

		goto exit1;



	nd.flags &= ~LOOKUP_PARENT;

	error = mnt_want_write(nd.path.mnt);

	error = mnt_want_write(path.mnt);

	if (error)

		goto exit1;

retry_deleg:

	mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = __lookup_hash(&nd.last, nd.path.dentry, nd.flags);

	mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);

	dentry = __lookup_hash(&last, path.dentry, lookup_flags);

	error = PTR_ERR(dentry);

	if (!IS_ERR(dentry)) {

		/* Why not before? Because we want correct error value */

		if (nd.last.name[nd.last.len])

		if (last.name[last.len])

			goto slashes;

		inode = dentry->d_inode;

		if (d_is_negative(dentry))

			goto slashes;

		ihold(inode);

		error = security_path_unlink(&nd.path, dentry);

		error = security_path_unlink(&path, dentry);

		if (error)

			goto exit2;

		error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode);

		error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode);

exit2:

		dput(dentry);

	}

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	mutex_unlock(&path.dentry->d_inode->i_mutex);

	if (inode)

		iput(inode);	/* truncate the inode here */

	inode = NULL;
@@ -3801,9 +3812,9 @@ static long do_unlinkat(int dfd, const char __user *pathname) 
		if (!error)

			goto retry_deleg;

	}

	mnt_drop_write(nd.path.mnt);

	mnt_drop_write(path.mnt);

exit1:

	path_put(&nd.path);

	path_put(&path);

	putname(name);

	if (retry_estale(error, lookup_flags)) {

		lookup_flags |= LOOKUP_REVAL;
@@ -4233,14 +4244,15 @@ EXPORT_SYMBOL(vfs_rename); 
SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,

		int, newdfd, const char __user *, newname, unsigned int, flags)

{

	struct dentry *old_dir, *new_dir;

	struct dentry *old_dentry, *new_dentry;

	struct dentry *trap;

	struct nameidata oldnd, newnd;

	struct path old_path, new_path;

	struct qstr old_last, new_last;

	int old_type, new_type;

	struct inode *delegated_inode = NULL;

	struct filename *from;

	struct filename *to;

	unsigned int lookup_flags = 0;

	unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;

	bool should_retry = false;

	int error;
@@ -4254,47 +4266,45 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, 
	if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))

		return -EPERM;



	if (flags & RENAME_EXCHANGE)

		target_flags = 0;



retry:

	from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);

	from = user_path_parent(olddfd, oldname,

				&old_path, &old_last, &old_type, lookup_flags);

	if (IS_ERR(from)) {

		error = PTR_ERR(from);

		goto exit;

	}



	to = user_path_parent(newdfd, newname, &newnd, lookup_flags);

	to = user_path_parent(newdfd, newname,

				&new_path, &new_last, &new_type, lookup_flags);

	if (IS_ERR(to)) {

		error = PTR_ERR(to);

		goto exit1;

	}



	error = -EXDEV;

	if (oldnd.path.mnt != newnd.path.mnt)

	if (old_path.mnt != new_path.mnt)

		goto exit2;



	old_dir = oldnd.path.dentry;

	error = -EBUSY;

	if (oldnd.last_type != LAST_NORM)

	if (old_type != LAST_NORM)

		goto exit2;



	new_dir = newnd.path.dentry;

	if (flags & RENAME_NOREPLACE)

		error = -EEXIST;

	if (newnd.last_type != LAST_NORM)

	if (new_type != LAST_NORM)

		goto exit2;



	error = mnt_want_write(oldnd.path.mnt);

	error = mnt_want_write(old_path.mnt);

	if (error)

		goto exit2;



	oldnd.flags &= ~LOOKUP_PARENT;

	newnd.flags &= ~LOOKUP_PARENT;

	if (!(flags & RENAME_EXCHANGE))

		newnd.flags |= LOOKUP_RENAME_TARGET;



retry_deleg:

	trap = lock_rename(new_dir, old_dir);

	trap = lock_rename(new_path.dentry, old_path.dentry);



	old_dentry = __lookup_hash(&oldnd.last, oldnd.path.dentry, oldnd.flags);

	old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags);

	error = PTR_ERR(old_dentry);

	if (IS_ERR(old_dentry))

		goto exit3;
@@ -4302,7 +4312,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, 
	error = -ENOENT;

	if (d_is_negative(old_dentry))

		goto exit4;

	new_dentry = __lookup_hash(&newnd.last, newnd.path.dentry, newnd.flags);

	new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags);

	error = PTR_ERR(new_dentry);

	if (IS_ERR(new_dentry))

		goto exit4;
@@ -4316,16 +4326,16 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, 


		if (!d_is_dir(new_dentry)) {

			error = -ENOTDIR;

			if (newnd.last.name[newnd.last.len])

			if (new_last.name[new_last.len])

				goto exit5;

		}

	}

	/* unless the source is a directory trailing slashes give -ENOTDIR */

	if (!d_is_dir(old_dentry)) {

		error = -ENOTDIR;

		if (oldnd.last.name[oldnd.last.len])

		if (old_last.name[old_last.len])

			goto exit5;

		if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])

		if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len])

			goto exit5;

	}

	/* source should not be ancestor of target */
@@ -4338,32 +4348,32 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, 
	if (new_dentry == trap)

		goto exit5;



	error = security_path_rename(&oldnd.path, old_dentry,

				     &newnd.path, new_dentry, flags);

	error = security_path_rename(&old_path, old_dentry,

				     &new_path, new_dentry, flags);

	if (error)

		goto exit5;

	error = vfs_rename(old_dir->d_inode, old_dentry,

			   new_dir->d_inode, new_dentry,

	error = vfs_rename(old_path.dentry->d_inode, old_dentry,

			   new_path.dentry->d_inode, new_dentry,

			   &delegated_inode, flags);

exit5:

	dput(new_dentry);

exit4:

	dput(old_dentry);

exit3:

	unlock_rename(new_dir, old_dir);

	unlock_rename(new_path.dentry, old_path.dentry);

	if (delegated_inode) {

		error = break_deleg_wait(&delegated_inode);

		if (!error)

			goto retry_deleg;

	}

	mnt_drop_write(oldnd.path.mnt);

	mnt_drop_write(old_path.mnt);

exit2:

	if (retry_estale(error, lookup_flags))

		should_retry = true;

	path_put(&newnd.path);

	path_put(&new_path);

	putname(to);

exit1:

	path_put(&oldnd.path);

	path_put(&old_path);

	putname(from);

	if (should_retry) {

		should_retry = false;