Tejun Heo <tj@xxxxxxxxxx> writes:
> Hello, Eric.
>
> On 03/31/2010 03:31 AM, Eric W. Biederman wrote:
>> From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
>>
>> Add all of the necessary bioler plate to support
> boiler :-)
>
>> +static int sysfs_test_super(struct super_block *sb, void *data)
>> +{
>> + struct sysfs_super_info *sb_info = sysfs_info(sb);
>> + struct sysfs_super_info *info = data;
>> + int found = 1;
>> + return found;
>> +}
>
> Can you please make it return bool?
Nope. That would mean I could not use it with sget.
>> static int sysfs_get_sb(struct file_system_type *fs_type,
>> int flags, const char *dev_name, void *data, struct vfsmount *mnt)
>> {
>> - return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
>> + struct sysfs_super_info *info;
>> + struct super_block *sb;
>> + int error;
>> +
>> + error = -ENOMEM;
>> + info = kzalloc(sizeof(*info), GFP_KERNEL);
>> + if (!info)
>> + goto out;
>> + sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info);
>> + if (IS_ERR(sb) || sb->s_fs_info != info)
>> + kfree(info);
>> + if (IS_ERR(sb)) {
>> + kfree(info);
>> + error = PTR_ERR(sb);
>> + goto out;
>> + }
>> + if (!sb->s_root) {
>> + sb->s_flags = flags;
>> + error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
>> + if (error) {
>> + deactivate_locked_super(sb);
>> + goto out;
>> + }
>> + sb->s_flags |= MS_ACTIVE;
>> + }
>> +
>> + simple_set_mnt(mnt, sb);
>> + error = 0;
>> +out:
>> + return error;
>> +}
>
> I haven't looked at later patches but I suppose this is gonna be
> filled with more meaningful stuff later.
Yes it will.
> One (possibly silly) thing
> that stands out compared to get_sb_single() is missing remount
> handling. Is it intended?
There is nothing for a remount to do so I ignore it. The only
thing that would possibly be meaningful is a read-only mount,
and nothing I know of sysfs suggests read-only mounts of sysfs
work, or make any sense.
>> index 30f5a44..030a39d 100644
>> --- a/fs/sysfs/sysfs.h
>> +++ b/fs/sysfs/sysfs.h
>> @@ -114,6 +114,9 @@ struct sysfs_addrm_cxt {
>> /*
>> * mount.c
>> */
>> +struct sysfs_super_info {
>> +};
>> +#define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info))
>
> Another nit picking. It would be better to wrap SB in the macro
> definition. Also, wouldn't an inline function be better?
Good spotting. That doesn't bite today but it will certainly bite
someday if it isn't fixed.
I wonder how that has slipped through the review all of this time.
Eric
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