Btrfs devel - Jan 2009 - [Patch] Btrfs: use BTRFS_VOL_NAME_MAX for struct btrfs_ioctl_vol_args

I found userspace tool, btrfsctl, uses BTRFS_VOL_NAME_MAX, and
it also looks that this one is more proper.

Kill BTRFS_PATH_NAME_MAX since no one will use it.

Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Chris Mason <chris.mason@oracle.com>

---
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c2aa33e..f229950 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -472,7 +472,7 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void
__user *arg)
 		goto out;
 	}
 
-	vol_args->name[BTRFS_PATH_NAME_MAX] = ''\0'';
+	vol_args->name[BTRFS_VOL_NAME_MAX] = ''\0'';
 	namelen = strlen(vol_args->name);
 
 	mutex_lock(&root->fs_info->volume_mutex);
@@ -576,7 +576,7 @@ static noinline int btrfs_ioctl_snap_create(struct file
*file,
 		goto out;
 	}
 
-	vol_args->name[BTRFS_PATH_NAME_MAX] = ''\0'';
+	vol_args->name[BTRFS_VOL_NAME_MAX] = ''\0'';
 	namelen = strlen(vol_args->name);
 	if (strchr(vol_args->name, ''/'')) {
 		ret = -EINVAL;
@@ -685,7 +685,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_root *root,
void __user *arg)
 		ret = -EFAULT;
 		goto out;
 	}
-	vol_args->name[BTRFS_PATH_NAME_MAX] = ''\0'';
+	vol_args->name[BTRFS_VOL_NAME_MAX] = ''\0'';
 	ret = btrfs_init_new_device(root, vol_args->name);
 
 out:
@@ -713,7 +713,7 @@ static long btrfs_ioctl_rm_dev(struct btrfs_root *root, void
__user *arg)
 		ret = -EFAULT;
 		goto out;
 	}
-	vol_args->name[BTRFS_PATH_NAME_MAX] = ''\0'';
+	vol_args->name[BTRFS_VOL_NAME_MAX] = ''\0'';
 	ret = btrfs_rm_device(root, vol_args->name);
 
 out:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index b320b10..f5d182a 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -22,12 +22,10 @@
 
 #define BTRFS_IOCTL_MAGIC 0x94
 #define BTRFS_VOL_NAME_MAX 255
-#define BTRFS_PATH_NAME_MAX 4087
 
-/* this should be 4k */
 struct btrfs_ioctl_vol_args {
 	__s64 fd;
-	char name[BTRFS_PATH_NAME_MAX + 1];
+	char name[BTRFS_VOL_NAME_MAX + 1];
 };
 
 struct btrfs_ioctl_clone_range_args {
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index db9fb3b..5facdbf 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -593,7 +593,7 @@ static long btrfs_control_ioctl(struct file *file, unsigned
int cmd,
 		ret = -EFAULT;
 		goto out;
 	}
-	len = strnlen(vol->name, BTRFS_PATH_NAME_MAX);
+	len = strnlen(vol->name, BTRFS_VOL_NAME_MAX);
 
 	switch (cmd) {
 	case BTRFS_IOC_SCAN_DEV:

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On Mon, Jan 19, 2009 at 08:57:32PM +0800, Américo Wang
wrote:
> 
> I found userspace tool, btrfsctl, uses BTRFS_VOL_NAME_MAX, and
> it also looks that this one is more proper.
> 
> Kill BTRFS_PATH_NAME_MAX since no one will use it.
> 
Nope, BTRFS_PATH_NAME_MAX is specifically used for the ioctl stuff, makes the
arguments 4k aligned, this patch is incorrect.  Thanks,

Josef
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On Mon, Jan 19, 2009 at 08:03:37AM -0500, Josef Bacik
wrote:
>On Mon, Jan 19, 2009 at 08:57:32PM +0800, Américo Wang wrote:
>> 
>> I found userspace tool, btrfsctl, uses BTRFS_VOL_NAME_MAX, and
>> it also looks that this one is more proper.
>> 
>> Kill BTRFS_PATH_NAME_MAX since no one will use it.
>> 
>
>Nope, BTRFS_PATH_NAME_MAX is specifically used for the ioctl stuff, makes
the
>arguments 4k aligned, this patch is incorrect.  Thanks,
Ok, then what is BTRFS_VOL_NAME_MAX? :)


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On Mon, 2009-01-19 at 21:12 +0800, Américo Wang wrote:
> On Mon, Jan 19, 2009 at 08:03:37AM -0500, Josef Bacik wrote:
> >On Mon, Jan 19, 2009 at 08:57:32PM +0800, Américo Wang wrote:
> >> 
> >> I found userspace tool, btrfsctl, uses BTRFS_VOL_NAME_MAX, and
> >> it also looks that this one is more proper.
> >> 
> >> Kill BTRFS_PATH_NAME_MAX since no one will use it.
> >> 
> >
> >Nope, BTRFS_PATH_NAME_MAX is specifically used for the ioctl stuff,
makes the
> >arguments 4k aligned, this patch is incorrect.  Thanks,
> 
> Ok, then what is BTRFS_VOL_NAME_MAX? :)
Right now it is only used in the progs.  The disk format doesn''t really
have a max there, it is just to keep names usable.  But, we should add a
check in the kernel ioctl side, are you interested in sending a patch
for it?

-chris


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On Wed, Jan 21, 2009 at 10:04:08AM -0500, Chris Mason
wrote:
>On Mon, 2009-01-19 at 21:12 +0800, Américo Wang wrote:
>> On Mon, Jan 19, 2009 at 08:03:37AM -0500, Josef Bacik wrote:
>> >On Mon, Jan 19, 2009 at 08:57:32PM +0800, Américo Wang wrote:
>> >> 
>> >> I found userspace tool, btrfsctl, uses BTRFS_VOL_NAME_MAX, and
>> >> it also looks that this one is more proper.
>> >> 
>> >> Kill BTRFS_PATH_NAME_MAX since no one will use it.
>> >> 
>> >
>> >Nope, BTRFS_PATH_NAME_MAX is specifically used for the ioctl stuff,
makes the
>> >arguments 4k aligned, this patch is incorrect.  Thanks,
>> 
>> Ok, then what is BTRFS_VOL_NAME_MAX? :)
>
>Right now it is only used in the progs.  The disk format doesn''t
really
>have a max there, it is just to keep names usable.  But, we should add a
>check in the kernel ioctl side, are you interested in sending a patch
>for it?
>
Yup, I will do.

Thanks.

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