lookup_open(): lock the parent shared unless O_CREAT is given (9cf843e3) · Commits · e / devices / android_kernel_teracube_2e

Documentation/filesystems/porting

+3 −0

Original line number	Diff line number	Diff line
		@@ -575,3 +575,6 @@ in your dentry operations instead.

		Old method is only used if the new one is absent; eventually it will
		be removed. Switch while you still can; the old one won't stay.
		--
		[mandatory]
		->atomic_open() calls without O_CREAT may happen in parallel.

+9 −3

Original line number	Diff line number	Diff line
		@@ -3084,7 +3084,7 @@ static int do_last(struct nameidata *nd,
		}

		retry_lookup:
		if (op->open_flag & (O_CREAT \| O_TRUNC \| O_WRONLY \| O_RDWR)) {
		if (open_flag & (O_CREAT \| O_TRUNC \| O_WRONLY \| O_RDWR)) {
		error = mnt_want_write(nd->path.mnt);
		if (!error)
		got_write = true;
		@@ -3094,9 +3094,15 @@ static int do_last(struct nameidata *nd,
		* dropping this one anyway.
		*/
		}
		if (open_flag & O_CREAT)
		inode_lock(dir->d_inode);
		else
		inode_lock_shared(dir->d_inode);
		error = lookup_open(nd, &path, file, op, got_write, opened);
		if (open_flag & O_CREAT)
		inode_unlock(dir->d_inode);
		else
		inode_unlock_shared(dir->d_inode);

		if (error <= 0) {
		if (error)