On Sun, Sep 16, 2012 at 5:59 AM, Jeff Layton <jlayton@xxxxxxxxx> wrote:
> On Sat, 15 Sep 2012 22:05:47 -0500
> shirishpargaonkar@xxxxxxxxx wrote:
>
>> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> Add support of Alternate Data Streams (ads).
>>
>> The generic access flags that cifs client currently employs are sufficient
>> for alternate data streams as well (MS-CIFS 2.2.4.64.1).
>>
>> The ads files have a : in the name, so that is used to differentiate
>> between a regular file and its alternate data streams as they
>> have the same file id.
>> This scheme applies to non-posix compliant servers such as Windows only.
>>
>> One operation that does not work is Rename (0x7).
>>
>>
>> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>> ---
>> fs/cifs/inode.c | 9 +++++++++
>> 1 files changed, 9 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
>> index cb79c7e..a28950a 100644
>> --- a/fs/cifs/inode.c
>> +++ b/fs/cifs/inode.c
>> @@ -709,10 +709,15 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
>> cFYI(1, "CIFSCheckMFSymlink: %d", tmprc);
>> }
>>
>> + if (strstr(full_path, ":"))
>> + fattr.cf_flags |= S_PRIVATE;
>> +
>
> While S_PRIVATE doesn't conflict with any of the other cf_flag values
> currently, I think it would be best to define a new CIFS_FATTR_* flag
> for this purpose.
>
>> if (!*inode) {
>> *inode = cifs_iget(sb, &fattr);
>> if (!*inode)
>> rc = -ENOMEM;
>> + else
>> + (*inode)->i_flags |= fattr.cf_flags;
>
> Uhh no...these flags have nothing to do with the i_flags. This will
> almost certainly break things.
>
>> } else {
>> cifs_fattr_to_inode(*inode, &fattr);
>> }
>> @@ -744,6 +749,10 @@ cifs_find_inode(struct inode *inode, void *opaque)
>> if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT))
>> return 0;
>>
>> + /* don't match inode with different flags */
>> + if ((inode->i_flags & S_PRIVATE) != (fattr->cf_flags & S_PRIVATE))
>> + return 0;
>> +
>> /* if it's not a directory or has no dentries, then flag it */
>> if (S_ISDIR(inode->i_mode) && !hlist_empty(&inode->i_dentry))
>> fattr->cf_flags |= CIFS_FATTR_INO_COLLISION;
>
> I'm still trying to understand the point of this patch. I guess the
> concern is that these files have the same uniqueid? So this will look
> like a hardlinked file metadata-wise, but will have different contents?
>
> If so, then isn't it possible that you'd have more than one alternate
> data stream attached to the file? In that case, it looks like the
> approach you're using here won't work since you're only designating the
> alternate data stream with a single flag value.
>
> --
> Jeff Layton <jlayton@xxxxxxxxx>
Jeff, yes, realized that after posting the patch. Will work on fixing
that and other comments.
Regards,
Shirish
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