On Tue 20 Apr 2021 at 01:08, Boris Burkov <bo...@bur.io> wrote:
On Mon, Apr 19, 2021 at 09:05:49PM +0800, Su Yue wrote:
Resize to nums without sign prefix makes false output:
btrfs fi resize 1:150g /srv/extra
Resize device id 1 (/dev/sdb1) from 298.09GiB to 0.00B
The resize operation would take effect though.
Fix it by handling the case if mod is 0 in check_resize_args().
Issue: #307
Reported-by: Chris Murphy <li...@colorremedies.com>
Signed-off-by: Su Yue <l...@damenly.su>
---
cmds/filesystem.c | 10 ++++++++++
1 file changed, 10 insertions(+)
---
Changelog:
v2:
Calculate u64 diff using max() and min().
Calculate mod by comparing new and old size.
diff --git a/cmds/filesystem.c b/cmds/filesystem.c
index 9e3cce687d6e..54d46470c53f 100644
--- a/cmds/filesystem.c
+++ b/cmds/filesystem.c
@@ -1158,6 +1158,16 @@ static int check_resize_args(const char
*amount, const char *path) {
}
old_size = di_args[dev_idx].total_bytes;
+ /* For target sizes without '+'/'-' sign prefix(e.g.
1:150g) */
+ if (mod == 0) {
+ new_size = diff;
+ diff = max(old_size, new_size) - min(old_size,
new_size);
+ if (new_size > old_size)
+ mod = 1;
+ else if (new_size < old_size)
+ mod = -1;
+ }
+
if (mod < 0) {
if (diff > old_size) {
error("current size is %s which is smaller
than %s",
This fix seems correct to me, but it feels a tiny bit
over-complicated.
Personally, I think it would be cleaner to do something like:
if (mod == 0) {
new_size = diff;
} else if (mod < 0) {
// >0 check
new_size = old_size - diff
} else {
// overflow check
new_size = old_size + diff
}
At this point, new_size is set correctly in all cases and we can
do the
print. I tested this version on some simple cases, and it seems
to work
ok as well.
Right. The first fix when I saw the code was same with yours.
Now I relaized that I was over thinking about boundary checks and
falling through checks are meaningless if mod is 0.
Just to clarify that my fix is wrong:
if (mod == 0) {
new_size = diff;
diff = max(old_size, new_size) - min(old_size,
new_size);
if (new_size > old_size)
mod = 1;
else if (new_size < old_size)
mod = -1;
} /* falls through to check diff */
if (mod < 0) { // new_size < old_size, diff = old_size -
new_size
// so diff < new_size
if (diff > old_size) // can't happen, if mod is 0
before.
...
} else if (mod > 0) {
// new_size > old_size so diff = new_size(u64) - old_size,
if (diff > ULLONG_MAX - old_size) // can't happen even
new_size is
// ULLONG_MAX if mod
is 0 before
...
}
Thanks for your suggestion, will send v3.
--
Su
Thanks for the fix,
Boris
--
2.30.1
