Messages in this thread | | | Subject | Re: [PATCH 1/6] sysfs: Basic support for multiple super blocks | From | (Eric W. Biederman) | Date | Tue, 30 Mar 2010 22:51:35 -0700 |
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Tejun Heo <tj@kernel.org> writes:
> Hello, Eric. > > On 03/31/2010 03:31 AM, Eric W. Biederman wrote: >> From: Eric W. Biederman <ebiederm@xmission.com> >> >> 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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