From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Subject: [PATCH -V5 2/8] vfs: Add name to file handle conversion support Date: Mon, 26 Apr 2010 23:04:00 +0530 Message-ID: <1272303246-25570-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1272303246-25570-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-fsdevel@vger.kernel.org, sfrench@us.ibm.com, "Aneesh Kumar K.V" To: hch@infradead.org, viro@zeniv.linux.org.uk, adilger@sun.com, corbet@lwn.net, serue@us.ibm.com, neilb@suse.de Return-path: Received: from e23smtp09.au.ibm.com ([202.81.31.142]:53092 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853Ab0DZReW (ORCPT ); Mon, 26 Apr 2010 13:34:22 -0400 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp09.au.ibm.com (8.14.3/8.13.1) with ESMTP id o3QHYLac002368 for ; Tue, 27 Apr 2010 03:34:21 +1000 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o3QHYKJn1474638 for ; Tue, 27 Apr 2010 03:34:20 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o3QHYJ6H011063 for ; Tue, 27 Apr 2010 03:34:20 +1000 In-Reply-To: <1272303246-25570-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Acked-by: Serge Hallyn Signed-off-by: Aneesh Kumar K.V --- fs/open.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 17 +++++++++ 2 files changed, 117 insertions(+), 0 deletions(-) diff --git a/fs/open.c b/fs/open.c index 74e5cd9..e9aae5c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -30,6 +30,8 @@ #include #include #include +#include +#include #include "internal.h" @@ -1206,3 +1208,101 @@ int nonseekable_open(struct inode *inode, struct file *filp) } EXPORT_SYMBOL(nonseekable_open); + +/* limit the handle size to some value */ +#define MAX_HANDLE_SZ 4096 +static long do_sys_name_to_handle(struct path *path, + struct file_handle __user *ufh) +{ + int retval; + int handle_size; + struct super_block *sb; + struct uuid *this_fs_id; + struct file_handle f_handle; + struct file_handle *handle = NULL; + + if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) + return -EFAULT; + + if (f_handle.handle_size > MAX_HANDLE_SZ) + return -EINVAL; + + handle = kmalloc(sizeof(struct file_handle) + f_handle.handle_size, + GFP_KERNEL); + if (!handle) { + retval = -ENOMEM; + goto err_out; + } + handle_size = f_handle.handle_size; + + /* we ask for a non connected handle */ + retval = exportfs_encode_fh(path->dentry, + (struct fid *)handle->f_handle, + &handle_size, 0); + /* convert handle size to bytes */ + handle_size *= sizeof(u32); + handle->handle_type = retval; + handle->handle_size = handle_size; + if (handle_size <= f_handle.handle_size) { + /* get the uuid */ + sb = path->mnt->mnt_sb; + if (sb->s_op->get_fsid) { + this_fs_id = sb->s_op->get_fsid(sb); + memcpy(handle->fsid.uuid, this_fs_id->uuid, + sizeof(handle->fsid.uuid)); + } else + memset(handle->fsid.uuid, 0, sizeof(handle->fsid.uuid)); + retval = 0; + } else { + /* + * set the handle_size to zero so we copy only + * non variable part of the file_handle + */ + handle_size = 0; + retval = -EOVERFLOW; + } + if (copy_to_user(ufh, handle, + sizeof(struct file_handle) + handle_size)) + retval = -EFAULT; + + kfree(handle); +err_out: + return retval; +} + +SYSCALL_DEFINE2(name_to_handle, const char __user *, name, + struct file_handle __user *, handle) +{ + long ret; + struct path path; + + /* Follow links */ + ret = user_path(name, &path); + if (ret) + return ret; + + ret = do_sys_name_to_handle(&path, handle); + path_put(&path); + + /* avoid REGPARM breakage on x86: */ + asmlinkage_protect(2, ret, name, handle); + return ret; +} + +SYSCALL_DEFINE2(lname_to_handle, const char __user *, name, + struct file_handle __user *, handle) +{ + long ret; + struct path path; + + ret = user_lpath(name, &path); + if (ret) + return ret; + + ret = do_sys_name_to_handle(&path, handle); + path_put(&path); + + /* avoid REGPARM breakage on x86: */ + asmlinkage_protect(2, ret, name, handle); + return ret; +} diff --git a/include/linux/fs.h b/include/linux/fs.h index 39d57bc..da28b80 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -948,6 +948,20 @@ struct file { unsigned long f_mnt_write_state; #endif }; + +struct uuid { + char uuid[16]; +}; + +struct file_handle { + int handle_size; + int handle_type; + /* File system identifier */ + struct uuid fsid; + /* file identifier */ + char f_handle[0]; +}; + extern spinlock_t files_lock; #define file_list_lock() spin_lock(&files_lock); #define file_list_unlock() spin_unlock(&files_lock); @@ -1580,6 +1594,7 @@ struct super_operations { ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t); #endif int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t); + struct uuid *(*get_fsid)(struct super_block *); }; /* @@ -2328,6 +2343,8 @@ extern struct super_block *get_super(struct block_device *); extern struct super_block *get_active_super(struct block_device *bdev); extern struct super_block *user_get_super(dev_t); extern void drop_super(struct super_block *sb); +extern struct super_block *fs_get_sb(struct uuid *fsid); + extern int dcache_dir_open(struct inode *, struct file *); extern int dcache_dir_close(struct inode *, struct file *); -- 1.7.0.4.360.g11766c