On Apr 20, 2012, at 5:25 PM, Adamson, Dros wrote:
> On Apr 20, 2012, at 3:30 PM, Chuck Lever wrote:
>
>>
>> On Apr 20, 2012, at 3:21 PM, Weston Andros Adamson wrote:
>>
>>> nfs4_path() was parsing the path component by splitting on the first colon.
>>> This is wrong when an IPv6 address is used to mount a server.
>>>
>>> For example, having mounted 'fc00::10:/export', nfs4_path() returned
>>> ':10:/export'. This causes referrals (using IPv4 or IPv6 addresses) to fail
>>> in nfs4_validate_fspath().
>>>
>>> Parsing the path component by using the *last* colon works with
>>> IPv6 as well as IPv4 addrs.
>>
>> These ad hoc fixes give me the willies.
>>
>> During a referral, how is the server name and export path getting recombined? In fs_locations data, these are separate. In the forward mount path, IPv6 addresses are escaped via square brackets.
>
> Again, the string that needs to be split into (server, path) is not the fs_locations side -- those are already separated. What's not separated is the result of nfs_path().
>
>> (Having not looked at this code in years), is there some way we can keep the server name and path separate here so we don't have to reparse?
>
> nfs_path() walks up the dentry tree until it hits the root dentry of the nfs mount, then it uses dentry.d_fsdata to get the "dev_name" of the mountpoint (<server>:<path>) to make <server>:<rootpath + path to the dentry>.
>
> The problem I'm having is how we can generate the string "<rootpath of parent mount>/<path-to-current-dentry>" without adding [] escaping to dev_name, or adding another variable to dentry (not likely!).
>
To be clear: the problem is *not* with IPv6 addrs in FS_LOCATIONS attrs. They work if the parent mount is IPv4/dns. The problem is when the parent mount is IPv6 *no* referrals work (IPv4, IPv6 or DNS), because of the issue described above.
> -dros
>
>>
>>> Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxx>
>>> ---
>>> fs/nfs/nfs4namespace.c | 2 +-
>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
>>> index 9c8eca3..dd3dd30 100644
>>> --- a/fs/nfs/nfs4namespace.c
>>> +++ b/fs/nfs/nfs4namespace.c
>>> @@ -59,7 +59,7 @@ static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
>>> char *limit;
>>> char *path = nfs_path(&limit, dentry, buffer, buflen);
>>> if (!IS_ERR(path)) {
>>> - char *colon = strchr(path, ':');
>>> + char *colon = strrchr(path, ':');
>>> if (colon && colon < limit)
>>> path = colon + 1;
>>> }
>>> --
>>> 1.7.4.4
>>>
>>> --
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>
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