On 05/23/2012 01:21 PM, Goffredo Baroncelli wrote:
> Hi
>
> On 05/17/2012 02:08 PM, Liu Bo wrote:
>> This patch fixes two bugs:
>>
>> When we do not assigne a device id for the resizer,
>> - it will only take one device to resize, which is supposed to apply on
>> all available devices.
>> - it will take 'id 1' device as default, and this will cause a bug as we
>> may have removed the 'id 1' device from the filesystem.
>>
>> After this patch, we can find all available devices by searching the
>> chunk tree and resize them:
>
>
> I am not sure that this is a sane default for all resizing.
>
> If the user want to resize to MAX, I agree that it is a sane default,
> but when the user want to shrink or enlarge of a fixed quantity, the
> user should specific the dev id. Because the shrinking and or the
> enlarging should be evaluated case by case.
>
> My suggestion is to change the code at kernel level so in case of
> multi-volume file-system the user *has* to specify the device to shrink
> and/or enlarge.
> Should be the user space btrfs tool to handle the check and the growing
> (i.e: if the new size is max, automatically grow all the device up to
> max; otherwise the user should specific the device to shrink and/or
> enlarge).
>
Hi,
It is quite easy to do what you expect, but IMO that will confuse users a lot...
With this patch, you can still assign a specific dev id to resize what you want
:)
thanks,
liubo
> BR
> Goffredo
>
>
>> $ mkfs.btrfs /dev/sdb7
>> $ mount /dev/sdb7 /mnt/btrfs/
>> $ btrfs dev add /dev/sdb8 /mnt/btrfs/
>>
>> $ btrfs fi resize -100m /mnt/btrfs/
>> then we can get from dmesg:
>> btrfs: new size for /dev/sdb7 is 980844544
>> btrfs: new size for /dev/sdb8 is 980844544
>>
>> $ btrfs fi resize max /mnt/btrfs
>> then we can get from dmesg:
>> btrfs: new size for /dev/sdb7 is 1085702144
>> btrfs: new size for /dev/sdb8 is 1085702144
>>
>> $ btrfs fi resize 1:-100m /mnt/btrfs
>> then we can get from dmesg:
>> btrfs: resizing devid 1
>> btrfs: new size for /dev/sdb7 is 980844544
>>
>> $ btrfs fi resize 1:-100m /mnt/btrfs
>> then we can get from dmesg:
>> btrfs: resizing devid 2
>> btrfs: new size for /dev/sdb8 is 980844544
>>
>> Signed-off-by: Liu Bo <liubo2...@cn.fujitsu.com>
>> ---
>> fs/btrfs/ioctl.c | 101
>> ++++++++++++++++++++++++++++++++++++++++++++----------
>> 1 files changed, 83 insertions(+), 18 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index ec2245d..d9a4fa8 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -1250,12 +1250,51 @@ out_ra:
>> return ret;
>> }
>>
>> +static struct btrfs_device *get_avail_device(struct btrfs_root *root, u64
>> devid)
>> +{
>> + struct btrfs_key key;
>> + struct btrfs_path *path;
>> + struct btrfs_dev_item *dev_item;
>> + struct btrfs_device *device = NULL;
>> + int ret;
>> +
>> + path = btrfs_alloc_path();
>> + if (!path)
>> + return ERR_PTR(-ENOMEM);
>> +
>> + key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
>> + key.offset = devid;
>> + key.type = BTRFS_DEV_ITEM_KEY;
>> +
>> + ret = btrfs_search_slot(NULL, root->fs_info->chunk_root, &key,
>> + path, 0, 0);
>> + if (ret < 0) {
>> + device = ERR_PTR(ret);
>> + goto out;
>> + }
>> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
>> + if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
>> + key.type != BTRFS_DEV_ITEM_KEY) {
>> + device = NULL;
>> + goto out;
>> + }
>> + dev_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
>> + struct btrfs_dev_item);
>> + devid = btrfs_device_id(path->nodes[0], dev_item);
>> +
>> + device = btrfs_find_device(root, devid, NULL, NULL);
>> +out:
>> + btrfs_free_path(path);
>> + return device;
>> +}
>> +
>> static noinline int btrfs_ioctl_resize(struct btrfs_root *root,
>> void __user *arg)
>> {
>> - u64 new_size;
>> + u64 new_size = 0;
>> u64 old_size;
>> - u64 devid = 1;
>> + u64 orig_new_size = 0;
>> + u64 devid = (-1ULL);
>> struct btrfs_ioctl_vol_args *vol_args;
>> struct btrfs_trans_handle *trans;
>> struct btrfs_device *device = NULL;
>> @@ -1263,6 +1302,8 @@ static noinline int btrfs_ioctl_resize(struct
>> btrfs_root *root,
>> char *devstr = NULL;
>> int ret = 0;
>> int mod = 0;
>> + int scan_all = 1;
>> + int use_max = 0;
>>
>> if (root->fs_info->sb->s_flags & MS_RDONLY)
>> return -EROFS;
>> @@ -1295,8 +1336,31 @@ static noinline int btrfs_ioctl_resize(struct
>> btrfs_root *root,
>> devid = simple_strtoull(devstr, &end, 10);
>> printk(KERN_INFO "btrfs: resizing devid %llu\n",
>> (unsigned long long)devid);
>> + scan_all = 0;
>> }
>> - device = btrfs_find_device(root, devid, NULL, NULL);
>> +
>> + if (!strcmp(sizestr, "max")) {
>> + use_max = 1;
>> + } else {
>> + if (sizestr[0] == '-') {
>> + mod = -1;
>> + sizestr++;
>> + } else if (sizestr[0] == '+') {
>> + mod = 1;
>> + sizestr++;
>> + }
>> + orig_new_size = memparse(sizestr, NULL);
>> + if (orig_new_size == 0) {
>> + ret = -EINVAL;
>> + goto out_free;
>> + }
>> + }
>> +
>> + if (devid < (-1ULL))
>> + device = btrfs_find_device(root, devid, NULL, NULL);
>> + else
>> + device = get_avail_device(root, 0);
>> +again:
>> if (!device) {
>> printk(KERN_INFO "btrfs: resizer unable to find device %llu\n",
>> (unsigned long long)devid);
>> @@ -1310,22 +1374,10 @@ static noinline int btrfs_ioctl_resize(struct
>> btrfs_root *root,
>> goto out_free;
>> }
>>
>> - if (!strcmp(sizestr, "max"))
>> + if (use_max)
>> new_size = device->bdev->bd_inode->i_size;
>> - else {
>> - if (sizestr[0] == '-') {
>> - mod = -1;
>> - sizestr++;
>> - } else if (sizestr[0] == '+') {
>> - mod = 1;
>> - sizestr++;
>> - }
>> - new_size = memparse(sizestr, NULL);
>> - if (new_size == 0) {
>> - ret = -EINVAL;
>> - goto out_free;
>> - }
>> - }
>> + else
>> + new_size = orig_new_size;
>>
>> old_size = device->total_bytes;
>>
>> @@ -1365,7 +1417,20 @@ static noinline int btrfs_ioctl_resize(struct
>> btrfs_root *root,
>> } else if (new_size < old_size) {
>> ret = btrfs_shrink_device(device, new_size);
>> }
>> + if (ret)
>> + goto out_free;
>>
>> + if (scan_all) {
>> + /* next available device */
>> + device = get_avail_device(root, device->devid + 1);
>> + if (!device)
>> + goto out_free;
>> + if (IS_ERR(device)) {
>> + ret = PTR_ERR(device);
>> + goto out_free;
>> + }
>> + goto again;
>> + }
>> out_free:
>> kfree(vol_args);
>> out:
>
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