On 11/18/19 8:02 PM, Qu Wenruo wrote:
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.
Umm.. Why?
(IMHO reasoning adds clarity to the technical discussions. my 1c).
That's the root problem the patch is going to solve.
IMO this patch does not the solve the root of the problem and its
approach is wrong.
The core problem as I see - currently we are determining the required
size for the replace-target by means of source-disk size, instead it
should be calculated by the source-disk space consumption.
Also warn if target is smaller than source and fail if target is
smaller than the consumption by the source-disk.
IMO changing the size of the missing device is point less. What if
in between the resize and replace the missing device reappears
in the following unmount and mount.
Thanks, Anand
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;
}
