On 2019/11/18 下午7:38, Anand Jain wrote:
> On 18/11/19 3:05 PM, Qu Wenruo wrote:
>> One user reported an use case where one device can't be replaced due to
>> tiny device size difference.
>>
>> Since it's a RAID10 fs, if we go regular "remove missing" it can take a
>> long time and even not be possible due to lack of space.
>>
>> So here we work around this situation by allowing user to shrink missing
>> device.
>> Then user can go shrink the device first, then replace it.
>
>
> Why not introduce --resize option in the replace command.
> Which shall allow replace command to resize the source-device
> to the size of the replace target-device.
Nope, it won't work for degraded mount.
That's the root problem the patch is going to solve.
Thanks,
Qu
>
> Thanks, Anand
>
>> Reported-by: Nathan Dehnel <ncdehnel@xxxxxxxxx>
>> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
>> ---
>> fs/btrfs/ioctl.c | 29 +++++++++++++++++++++++++----
>> 1 file changed, 25 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index de730e56d3f5..ebd2f40aca6f 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -1604,6 +1604,7 @@ static noinline int btrfs_ioctl_resize(struct
>> file *file,
>> char *sizestr;
>> char *retptr;
>> char *devstr = NULL;
>> + bool missing;
>> int ret = 0;
>> int mod = 0;
>> @@ -1651,7 +1652,10 @@ static noinline int btrfs_ioctl_resize(struct
>> file *file,
>> goto out_free;
>> }
>> - if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state)) {
>> +
>> + missing = test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state);
>> + if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) &&
>> + !missing) {
>> btrfs_info(fs_info,
>> "resizer unable to apply on readonly device %llu",
>> devid);
>> @@ -1659,13 +1663,24 @@ static noinline int btrfs_ioctl_resize(struct
>> file *file,
>> goto out_free;
>> }
>> - if (!strcmp(sizestr, "max"))
>> + if (!strcmp(sizestr, "max")) {
>> + if (missing) {
>> + btrfs_info(fs_info,
>> + "'max' can't be used for missing device %llu",
>> + devid);
>> + ret = -EPERM;
>> + goto out_free;
>> + }
>> new_size = device->bdev->bd_inode->i_size;
>> - else {
>> + } else {
>> if (sizestr[0] == '-') {
>> mod = -1;
>> sizestr++;
>> } else if (sizestr[0] == '+') {
>> + if (missing)
>> + btrfs_info(fs_info,
>> + "'+size' can't be used for missing device %llu",
>> + devid);
>> mod = 1;
>> sizestr++;
>> }
>> @@ -1694,6 +1709,12 @@ static noinline int btrfs_ioctl_resize(struct
>> file *file,
>> ret = -ERANGE;
>> goto out_free;
>> }
>> + if (missing) {
>> + ret = -EINVAL;
>> + btrfs_info(fs_info,
>> + "can not increase device size for missing device %llu",
>> + devid);
>> + }
>> new_size = old_size + new_size;
>> }
>> @@ -1701,7 +1722,7 @@ static noinline int btrfs_ioctl_resize(struct
>> file *file,
>> ret = -EINVAL;
>> goto out_free;
>> }
>> - if (new_size > device->bdev->bd_inode->i_size) {
>> + if (!missing && new_size > device->bdev->bd_inode->i_size) {
>> ret = -EFBIG;
>> goto out_free;
>> }
>>
>
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