From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Subject: [RFC PATCH 1/3] vfs: Add name to file handle conversion support Date: Fri, 19 Feb 2010 11:12:27 +0530 Message-ID: <1266558149-11460-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1266558149-11460-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-fsdevel@vger.kernel.org, "Aneesh Kumar K.V" To: hch@infradead.org, viro@zeniv.linux.org.uk Return-path: Received: from e28smtp06.in.ibm.com ([122.248.162.6]:59251 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751993Ab0BSFmq (ORCPT ); Fri, 19 Feb 2010 00:42:46 -0500 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by e28smtp06.in.ibm.com (8.14.3/8.13.1) with ESMTP id o1J5gigc020403 for ; Fri, 19 Feb 2010 11:12:44 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o1J5gi3S1654784 for ; Fri, 19 Feb 2010 11:12:44 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o1J5ghPF023858 for ; Fri, 19 Feb 2010 16:42:44 +1100 In-Reply-To: <1266558149-11460-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Signed-off-by: Aneesh Kumar K.V --- fs/open.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 7 +++++ 2 files changed, 71 insertions(+), 0 deletions(-) diff --git a/fs/open.c b/fs/open.c index 040cef7..f5a8420 100644 --- a/fs/open.c +++ b/fs/open.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "internal.h" @@ -1079,6 +1080,69 @@ SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, int, mode) return ret; } +static int do_sys_name_to_handle(const char __user *name, + struct file_handle *handle) +{ + int retval; + struct path path; + struct inode *inode; + void *f_handle = NULL; + int handle_size = handle->handle_size; + + retval = user_lpath(name, &path); + if (retval) + return retval; + + inode = path.dentry->d_inode; + + f_handle = kmalloc(handle_size, GFP_KERNEL); + if (!f_handle) { + retval = -ENOMEM; + goto err_out; + } + + /* we ask for a non connected handle */ + retval = exportfs_encode_fh(path.dentry, (struct fid *)f_handle, + &handle_size, 0); + handle->handle_type = retval; + if (handle_size < handle->handle_size) { + if (copy_to_user(handle->f_handle, f_handle, + handle_size*sizeof(u32))) + retval = -EFAULT; + retval = 0; + } else + retval = -EAGAIN; + handle->handle_size = handle_size; + kfree(f_handle); + +err_out: + path_put(&path); + return retval; +} + +SYSCALL_DEFINE2(name_to_handle, const char __user *, name, + struct file_handle __user *, handle) +{ + long ret; + struct file_handle f_handle; + if (copy_from_user(&f_handle, handle, sizeof(struct file_handle))) { + ret = -EFAULT; + goto err_out; + } + ret = do_sys_name_to_handle(name, &f_handle); + if (copy_to_user(&handle->handle_type, + &f_handle.handle_type, sizeof(f_handle.handle_type)) || + copy_to_user(&handle->handle_size, + &f_handle.handle_size, sizeof(f_handle.handle_size))) { + ret = -EFAULT; + } +err_out: + /* avoid REGPARM breakage on x86: */ + asmlinkage_protect(2, ret, name, handle); + return ret; +} + + SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, int, mode) { diff --git a/include/linux/fs.h b/include/linux/fs.h index b1bcb27..5bef1e9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -945,6 +945,13 @@ struct file { unsigned long f_mnt_write_state; #endif }; + +struct file_handle { + int handle_size; + int handle_type; + void *f_handle; +}; + extern spinlock_t files_lock; #define file_list_lock() spin_lock(&files_lock); #define file_list_unlock() spin_unlock(&files_lock); -- 1.7.0.31.g1df487