linux-kernel - Re: [PATCH 4/7] fs: make remaining filesystems use .rename2

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Date:   Tue, 23 Aug 2016 19:29:32 +0300
From:   Boaz Harrosh <openosd@...il.com>
To:     Miklos Szeredi <mszeredi@...hat.com>, linux-fsdevel@...r.kernel.org
CC:     linux-kernel@...r.kernel.org, Al Viro <viro@...iv.linux.org.uk>,
        Eric Van Hensbergen <ericvh@...il.com>,
        David Howells <dhowells@...hat.com>,
        Ilya Dryomov <idryomov@...il.com>,
        Jan Harkes <jaharkes@...cmu.edu>,
        Tyler Hicks <tyhicks@...onical.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Oleg Drokin <oleg.drokin@...el.com>,
        Trond Myklebust <trond.myklebust@...marydata.com>,
        Mark Fasheh <mfasheh@...e.com>,
        Mike Marshall <hubcap@...ibond.com>
Subject: Re: [PATCH 4/7] fs: make remaining filesystems use .rename2

On 08/23/2016 07:24 PM, Boaz Harrosh wrote:
> On 08/23/2016 05:05 PM, Miklos Szeredi wrote:
>> This is trivial to do:
>>
>>  - add flags argument to foo_rename()
>>  - check if flags is zero
>>  - assign foo_rename() to .rename2 instead of .rename
>>
>> This doesn't mean it's impossible to support RENAME_NOREPLACE for these
>> filesystems, but it is not trivial, like for local filesystems.
>> RENAME_NOREPLACE must guarantee atomicity (i.e. it shouldn't be possible
>> for a file to be created on one host while it is overwritten by rename on
>> another host).
>>
>> Filesystems converted:
>>
>> 9p, afs, ceph, coda, ecryptfs, exofs, kernfs, lustre, ncpfs, nfs, ocfs2,
>> orangefs.
>>
>> After this, we can get rid of the duplicate interfaces for rename.
>>
>> Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
>> Cc: Eric Van Hensbergen <ericvh@...il.com>
>> Cc: David Howells <dhowells@...hat.com>
>> Cc: Ilya Dryomov <idryomov@...il.com>
>> Cc: Jan Harkes <jaharkes@...cmu.edu>
>> Cc: Tyler Hicks <tyhicks@...onical.com>
>> Cc: Boaz Harrosh <ooo@...ctrozaur.com>
> 
> Hi exofs is not a distributed file system in the nfs-client 
> sense. All meta-data operations happen on the single exofs mount.
> The distribution of an exofs cluster is done by an NFSD-like daemon
> that supports pNFS, and an std pNFS-client.
> So the code you see below is just the same as an ext4 FS with
> a raid of iscsi devices below it. (Even if then later this FS is
> exported by an NFSD server)
> 
> That said it is fine as is don't sweat over this unused FS so:
> ACK-by: Boaz Harrosh <ooo@...ctrozaur.com>
> 
> <>
> 
>> diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
>> index 622a686bb08b..897280163f3c 100644
>> --- a/fs/exofs/namei.c
>> +++ b/fs/exofs/namei.c
>> @@ -227,7 +227,8 @@ static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
>>  }
>>  
>>  static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
>> -		struct inode *new_dir, struct dentry *new_dentry)
>> +			struct inode *new_dir, struct dentry *new_dentry,
>> +			unsigned int flags)
>>  {
>>  	struct inode *old_inode = d_inode(old_dentry);
>>  	struct inode *new_inode = d_inode(new_dentry);
>> @@ -237,6 +238,9 @@ static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
>>  	struct exofs_dir_entry *old_de;
>>  	int err = -ENOENT;
>>  
>> +	if (flags)
>> +		return -EINVAL;
>> +

+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+

And move to the other patch if you feel like it

>>  	old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
>>  	if (!old_de)
>>  		goto out;
>> @@ -310,7 +314,7 @@ const struct inode_operations exofs_dir_inode_operations = {
>>  	.mkdir  	= exofs_mkdir,
>>  	.rmdir  	= exofs_rmdir,
>>  	.mknod  	= exofs_mknod,
>> -	.rename 	= exofs_rename,
>> +	.rename2	= exofs_rename,
>>  	.setattr	= exofs_setattr,
>>  };
>>  
> <>
>