When we call rmmod it will fail if the refcnt is greater than 0.
This is expected, however, if using test modules such as scsi_debug,
userspace tests may expect that once userspace is done issuing out
commands it can safely remove the module, and the module will be
removed.
This is not true for few reasons. First, a module might take a while
to quiesce after its used. This varies module by module. For example,
at least for scsi_debug there is one patch to help with this but
that is not sufficient to address all the removal issues, it just helps
quiesce the module faster. If something like LVM pvremove is used, as in
the case of generic/108, it may take time before the module's refcnt goes
to 0 even if DM_DEFERRED_REMOVE is *not* used and even if udevadm settle
is used. Even *after* all this... the module refcnt is still very
fickle. For example, any blkdev_open() against a block device will bump
a module refcnt up and we have little control over stopping these
sporadic userspace calls after a test. A failure on module removal then
just becomes an inconvenience on false positives.
This was first observed on scsi_debug [0]. Doug worked on a patch to
help the driver quiesce [1]. Later the issue has been determined to be
generic [2]. The only way to properly resolve these issues is with a
patient module remover. The kernel used to support a wait for the
delete_module() system call, however this was later deprecated into
kmod with a 10 second userspace sleep. That 10 second sleep is long gone
from kmod now though. I've posted patches now for a kmod patient module
remover then [3], in light of the fact that this issue is generic and
the only way to then properly deal with this is implementing a userspace
patient module remover.
Use the kmod patient module remover when supported, otherwise we open
code our own solution inside fstests. We default to a timeout of 100
seconds. Each test can override the timeout by setting the variable
MODPROBE_PATIENT_RM_TIMEOUT_SECONDS or setting it to "forever" if they
wish for the patience to be infinite.
This uses kmod's patient module remover if you have that feature,
otherwise we open code a solution in fstests which is a simplified
version of what has been proposed for kmod.
[0] https://bugzilla.kernel.org/show_bug.cgi?id=212337
[1] https://lore.kernel.org/linux-scsi/[email protected]/
[2] https://bugzilla.kernel.org/show_bug.cgi?id=214015
[3] https://lkml.kernel.org/r/[email protected]
Signed-off-by: Luis Chamberlain <[email protected]>
---
common/config | 31 +++++++++++++++
common/module | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 138 insertions(+)
diff --git a/common/config b/common/config
index 005fd50a..9b8a2bc4 100644
--- a/common/config
+++ b/common/config
@@ -252,6 +252,37 @@ if [[ "$UDEV_SETTLE_PROG" == "" || ! -d /proc/net ]]; then
fi
export UDEV_SETTLE_PROG
+# Set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS to "forever" if you want the patient
+# modprobe removal to run forever trying to remove a module.
+MODPROBE_REMOVE_PATIENT=""
+modprobe --help | grep -q -1 "remove-patiently"
+if [[ $? -ne 0 ]]; then
+ if [[ -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
+ # We will open code our own implementation of patien module
+ # remover in fstests. Use 100 second default.
+ export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS="100"
+ fi
+else
+ MODPROBE_RM_PATIENT_TIMEOUT_ARGS=""
+ if [[ ! -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
+ if [[ "$MODPROBE_PATIENT_RM_TIMEOUT_MS" != "forever" ]]; then
+ MODPROBE_PATIENT_RM_TIMEOUT_MS="$((MODPROBE_PATIENT_RM_TIMEOUT_SECONDS * 1000))"
+ MODPROBE_RM_PATIENT_TIMEOUT_ARGS="-t $MODPROBE_PATIENT_RM_TIMEOUT_MS"
+ fi
+ else
+ # We export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS here for parity
+ # with environments without support for modprobe -p, but we
+ # only really need it exported right now for environments which
+ # don't have support for modprobe -p to implement our own
+ # patient module removal support within fstests.
+ export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS="100"
+ MODPROBE_PATIENT_RM_TIMEOUT_MS="$((MODPROBE_PATIENT_RM_TIMEOUT_SECONDS * 1000))"
+ MODPROBE_RM_PATIENT_TIMEOUT_ARGS="-t $MODPROBE_PATIENT_RM_TIMEOUT_MS"
+ fi
+ MODPROBE_REMOVE_PATIENT="modprobe -p $MODPROBE_RM_TIMEOUT_ARGS"
+fi
+export MODPROBE_REMOVE_PATIENT
+
export MKFS_XFS_PROG=$(type -P mkfs.xfs)
export MKFS_EXT4_PROG=$(type -P mkfs.ext4)
export MKFS_UDF_PROG=$(type -P mkudffs)
diff --git a/common/module b/common/module
index 39e4e793..03953fa1 100644
--- a/common/module
+++ b/common/module
@@ -4,6 +4,8 @@
#
# Routines for messing around with loadable kernel modules
+source common/config
+
# Return the module name for this fs.
_module_for_fs()
{
@@ -81,3 +83,108 @@ _get_fs_module_param()
{
cat /sys/module/${FSTYP}/parameters/${1} 2>/dev/null
}
+
+# checks the refcount and returns 0 if we can safely remove the module. rmmod
+# does this check for us, but we can use this to also iterate checking for this
+# refcount before we even try to remove the module. This is useful when using
+# debug test modules which take a while to quiesce.
+_patient_rmmod_check_refcnt()
+{
+ local module=$1
+ local refcnt=0
+
+ if [[ -f /sys/module/$module/refcnt ]]; then
+ refcnt=$(cat /sys/module/$module/refcnt 2>/dev/null)
+ if [[ $? -ne 0 || $refcnt -eq 0 ]]; then
+ return 0
+ fi
+ return 1
+ fi
+ return 0
+}
+
+# Patiently tries to wait to remove a module by ensuring first
+# the refcnt is 0 and then trying to persistently remove the module within
+# the time allowed. The timeout is configurable per test, just set
+# MODPROBE_PATIENT_RM_TIMEOUT_SECONDS prior to including this file.
+# If you want this to try forever just set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
+# to the special value of "forever". This applies to both cases where kmod
+# supports the patient module remover (modrobe -p) and where it does not.
+#
+# If your version of kmod supports modprobe -p, we instead use that
+# instead. Otherwise we have to implement a patient module remover
+# ourselves.
+_patient_rmmod()
+{
+ local module=$1
+ local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
+ local max_tries=0
+ local mod_ret=0
+ local refcnt_is_zero=0
+
+ if [[ ! -z $MODPROBE_REMOVE_PATIENT ]]; then
+ $MODPROBE_REMOVE_PATIENT $module
+ mod_ret=$?
+ if [[ $mod_ret -ne 0 ]]; then
+ echo "kmod patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max returned $mod_ret"
+ fi
+ return $mod_ret
+ fi
+
+ max_tries=$max_tries_max
+
+ while [[ "$max_tries" != "0" ]]; do
+ _patient_rmmod_check_refcnt $module
+ if [[ $? -eq 0 ]]; then
+ refcnt_is_zero=1
+ break
+ fi
+ sleep 1
+ if [[ "$max_tries" == "forever" ]]; then
+ continue
+ fi
+ let max_tries=$max_tries-1
+ done
+
+ if [[ $refcnt_is_zero -ne 1 ]]; then
+ echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
+ return -1
+ fi
+
+ # If we ran out of time but our refcnt check confirms we had
+ # a refcnt of 0, just try to remove the module once.
+ if [[ "$max_tries" == "0" ]]; then
+ modprobe -r $module
+ return $?
+ fi
+
+ # If we have extra time left. Use the time left to now try to
+ # persistently remove the module. We do this because although through
+ # the above we found refcnt to be 0, removal can still fail since
+ # userspace can always race to bump the refcnt. An example is any
+ # blkdev_open() calls against a block device. These issues have been
+ # tracked and documented in the following bug reports, which justifies
+ # our need to do this in userspace:
+ # https://bugzilla.kernel.org/show_bug.cgi?id=212337
+ # https://bugzilla.kernel.org/show_bug.cgi?id=214015
+ while [[ $max_tries != 0 ]]; do
+ if [[ -d /sys/module/$module ]]; then
+ modprobe -r $module 2> /dev/null
+ mod_ret=$?
+ if [[ $mod_ret == 0 ]]; then
+ break;
+ fi
+ sleep 1
+ if [[ "$max_tries" == "forever" ]]; then
+ continue
+ fi
+ let max_tries=$max_tries-1
+ fi
+ done
+
+ if [[ $mod_ret -ne 0 ]]; then
+ echo "custom patient module removal for $module timed out trying to remove $module using timeout of $max_tries_max last try returned $mod_ret"
+ fi
+
+ return $mod_ret
+}
--
2.30.2
On Wed, Aug 11, 2021 at 08:45:11AM -0700, Luis Chamberlain wrote:
> When we call rmmod it will fail if the refcnt is greater than 0.
> This is expected, however, if using test modules such as scsi_debug,
> userspace tests may expect that once userspace is done issuing out
> commands it can safely remove the module, and the module will be
> removed.
>
> This is not true for few reasons. First, a module might take a while
> to quiesce after its used. This varies module by module. For example,
> at least for scsi_debug there is one patch to help with this but
> that is not sufficient to address all the removal issues, it just helps
> quiesce the module faster. If something like LVM pvremove is used, as in
> the case of generic/108, it may take time before the module's refcnt goes
> to 0 even if DM_DEFERRED_REMOVE is *not* used and even if udevadm settle
> is used. Even *after* all this... the module refcnt is still very
> fickle. For example, any blkdev_open() against a block device will bump
> a module refcnt up and we have little control over stopping these
> sporadic userspace calls after a test. A failure on module removal then
> just becomes an inconvenience on false positives.
>
> This was first observed on scsi_debug [0]. Doug worked on a patch to
> help the driver quiesce [1]. Later the issue has been determined to be
> generic [2]. The only way to properly resolve these issues is with a
> patient module remover. The kernel used to support a wait for the
> delete_module() system call, however this was later deprecated into
> kmod with a 10 second userspace sleep. That 10 second sleep is long gone
> from kmod now though. I've posted patches now for a kmod patient module
> remover then [3], in light of the fact that this issue is generic and
> the only way to then properly deal with this is implementing a userspace
> patient module remover.
>
> Use the kmod patient module remover when supported, otherwise we open
> code our own solution inside fstests. We default to a timeout of 100
> seconds. Each test can override the timeout by setting the variable
> MODPROBE_PATIENT_RM_TIMEOUT_SECONDS or setting it to "forever" if they
> wish for the patience to be infinite.
>
> This uses kmod's patient module remover if you have that feature,
> otherwise we open code a solution in fstests which is a simplified
> version of what has been proposed for kmod.
>
> [0] https://bugzilla.kernel.org/show_bug.cgi?id=212337
> [1] https://lore.kernel.org/linux-scsi/[email protected]/
> [2] https://bugzilla.kernel.org/show_bug.cgi?id=214015
> [3] https://lkml.kernel.org/r/[email protected]
> Signed-off-by: Luis Chamberlain <[email protected]>
> ---
> common/config | 31 +++++++++++++++
> common/module | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
Please also update README to document the new configurable variables.
> 2 files changed, 138 insertions(+)
>
> diff --git a/common/config b/common/config
> index 005fd50a..9b8a2bc4 100644
> --- a/common/config
> +++ b/common/config
> @@ -252,6 +252,37 @@ if [[ "$UDEV_SETTLE_PROG" == "" || ! -d /proc/net ]]; then
> fi
> export UDEV_SETTLE_PROG
>
> +# Set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS to "forever" if you want the patient
> +# modprobe removal to run forever trying to remove a module.
> +MODPROBE_REMOVE_PATIENT=""
> +modprobe --help | grep -q -1 "remove-patiently"
> +if [[ $? -ne 0 ]]; then
> + if [[ -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
> + # We will open code our own implementation of patien module
> + # remover in fstests. Use 100 second default.
> + export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS="100"
100s as default seems a bit long to me, use 10s as in v1 patch?
> + fi
> +else
> + MODPROBE_RM_PATIENT_TIMEOUT_ARGS=""
> + if [[ ! -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
> + if [[ "$MODPROBE_PATIENT_RM_TIMEOUT_MS" != "forever" ]]; then
Should check MODPROBE_PATIENT_RM_TIMEOUT_SECONDS instead?
> + MODPROBE_PATIENT_RM_TIMEOUT_MS="$((MODPROBE_PATIENT_RM_TIMEOUT_SECONDS * 1000))"
> + MODPROBE_RM_PATIENT_TIMEOUT_ARGS="-t $MODPROBE_PATIENT_RM_TIMEOUT_MS"
> + fi
> + else
> + # We export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS here for parity
> + # with environments without support for modprobe -p, but we
> + # only really need it exported right now for environments which
> + # don't have support for modprobe -p to implement our own
> + # patient module removal support within fstests.
> + export MODPROBE_PATIENT_RM_TIMEOUT_SECONDS="100"
> + MODPROBE_PATIENT_RM_TIMEOUT_MS="$((MODPROBE_PATIENT_RM_TIMEOUT_SECONDS * 1000))"
> + MODPROBE_RM_PATIENT_TIMEOUT_ARGS="-t $MODPROBE_PATIENT_RM_TIMEOUT_MS"
> + fi
> + MODPROBE_REMOVE_PATIENT="modprobe -p $MODPROBE_RM_TIMEOUT_ARGS"
> +fi
> +export MODPROBE_REMOVE_PATIENT
> +
> export MKFS_XFS_PROG=$(type -P mkfs.xfs)
> export MKFS_EXT4_PROG=$(type -P mkfs.ext4)
> export MKFS_UDF_PROG=$(type -P mkudffs)
> diff --git a/common/module b/common/module
> index 39e4e793..03953fa1 100644
> --- a/common/module
> +++ b/common/module
> @@ -4,6 +4,8 @@
> #
> # Routines for messing around with loadable kernel modules
>
> +source common/config
> +
Seems there's no need to source common/config here, as it's sourced in
common/rc, which is sourced by every test.
> # Return the module name for this fs.
> _module_for_fs()
> {
> @@ -81,3 +83,108 @@ _get_fs_module_param()
> {
> cat /sys/module/${FSTYP}/parameters/${1} 2>/dev/null
> }
> +
> +# checks the refcount and returns 0 if we can safely remove the module. rmmod
> +# does this check for us, but we can use this to also iterate checking for this
> +# refcount before we even try to remove the module. This is useful when using
> +# debug test modules which take a while to quiesce.
> +_patient_rmmod_check_refcnt()
> +{
> + local module=$1
> + local refcnt=0
> +
> + if [[ -f /sys/module/$module/refcnt ]]; then
> + refcnt=$(cat /sys/module/$module/refcnt 2>/dev/null)
> + if [[ $? -ne 0 || $refcnt -eq 0 ]]; then
> + return 0
> + fi
> + return 1
> + fi
> + return 0
> +}
> +
> +# Patiently tries to wait to remove a module by ensuring first
> +# the refcnt is 0 and then trying to persistently remove the module within
> +# the time allowed. The timeout is configurable per test, just set
> +# MODPROBE_PATIENT_RM_TIMEOUT_SECONDS prior to including this file.
> +# If you want this to try forever just set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
> +# to the special value of "forever". This applies to both cases where kmod
> +# supports the patient module remover (modrobe -p) and where it does not.
> +#
> +# If your version of kmod supports modprobe -p, we instead use that
> +# instead. Otherwise we have to implement a patient module remover
> +# ourselves.
> +_patient_rmmod()
> +{
> + local module=$1
> + local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
> + local max_tries=0
> + local mod_ret=0
> + local refcnt_is_zero=0
> +
> + if [[ ! -z $MODPROBE_REMOVE_PATIENT ]]; then
> + $MODPROBE_REMOVE_PATIENT $module
> + mod_ret=$?
> + if [[ $mod_ret -ne 0 ]]; then
> + echo "kmod patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max returned $mod_ret"
> + fi
> + return $mod_ret
> + fi
> +
> + max_tries=$max_tries_max
> +
> + while [[ "$max_tries" != "0" ]]; do
Use "$max_tries -ne 0" to check inters seems better.
> + _patient_rmmod_check_refcnt $module
> + if [[ $? -eq 0 ]]; then
Like above
> + refcnt_is_zero=1
> + break
> + fi
> + sleep 1
> + if [[ "$max_tries" == "forever" ]]; then
> + continue
> + fi
> + let max_tries=$max_tries-1
> + done
> +
> + if [[ $refcnt_is_zero -ne 1 ]]; then
> + echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
> + return -1
> + fi
> +
> + # If we ran out of time but our refcnt check confirms we had
> + # a refcnt of 0, just try to remove the module once.
> + if [[ "$max_tries" == "0" ]]; then
$max_tries -eq 0
Thanks,
Eryu
> + modprobe -r $module
> + return $?
> + fi
> +
> + # If we have extra time left. Use the time left to now try to
> + # persistently remove the module. We do this because although through
> + # the above we found refcnt to be 0, removal can still fail since
> + # userspace can always race to bump the refcnt. An example is any
> + # blkdev_open() calls against a block device. These issues have been
> + # tracked and documented in the following bug reports, which justifies
> + # our need to do this in userspace:
> + # https://bugzilla.kernel.org/show_bug.cgi?id=212337
> + # https://bugzilla.kernel.org/show_bug.cgi?id=214015
> + while [[ $max_tries != 0 ]]; do
> + if [[ -d /sys/module/$module ]]; then
> + modprobe -r $module 2> /dev/null
> + mod_ret=$?
> + if [[ $mod_ret == 0 ]]; then
> + break;
> + fi
> + sleep 1
> + if [[ "$max_tries" == "forever" ]]; then
> + continue
> + fi
> + let max_tries=$max_tries-1
> + fi
> + done
> +
> + if [[ $mod_ret -ne 0 ]]; then
> + echo "custom patient module removal for $module timed out trying to remove $module using timeout of $max_tries_max last try returned $mod_ret"
> + fi
> +
> + return $mod_ret
> +}
> --
> 2.30.2
On Sun, Aug 15, 2021 at 08:29:42PM +0800, Eryu Guan wrote:
> On Wed, Aug 11, 2021 at 08:45:11AM -0700, Luis Chamberlain wrote:
> > common/config | 31 +++++++++++++++
> > common/module | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Please also update README to document the new configurable variables.
Got it.
> > 2 files changed, 138 insertions(+)
> >
> > diff --git a/common/config b/common/config
> > index 005fd50a..9b8a2bc4 100644
> > --- a/common/config
> > +++ b/common/config
>
> 100s as default seems a bit long to me, use 10s as in v1 patch?
In practice I tried using 10s and from my observations we *still* ran
into false positives. So from my own testing peace of mind I'd prefer at
least something higher, and if its going to be higher might as well go
with something which at least makes painfully safe. I'll go with 50s
for my next submission.
> > + fi
> > +else
> > + MODPROBE_RM_PATIENT_TIMEOUT_ARGS=""
> > + if [[ ! -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
> > + if [[ "$MODPROBE_PATIENT_RM_TIMEOUT_MS" != "forever" ]]; then
>
> Should check MODPROBE_PATIENT_RM_TIMEOUT_SECONDS instead?
Indeed will fix.
> > diff --git a/common/module b/common/module
> > index 39e4e793..03953fa1 100644
> > --- a/common/module
> > +++ b/common/module
> > @@ -4,6 +4,8 @@
> > #
> > # Routines for messing around with loadable kernel modules
> >
> > +source common/config
> > +
>
> Seems there's no need to source common/config here, as it's sourced in
> common/rc, which is sourced by every test.
OK.
> > + local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
<-- snip -->
> > + local max_tries=0
<-- snip -->
> > + max_tries=$max_tries_max
> > +
> > + while [[ "$max_tries" != "0" ]]; do
>
> Use "$max_tries -ne 0" to check inters seems better.
max_tries can be "forever", in which case this is -eq 0:
$ foo="forever"; if [[ $foo -eq 0 ]]; then echo buggy; else echo ok; fi
buggy
> > + refcnt_is_zero=1
> > + break
> > + fi
> > + sleep 1
> > + if [[ "$max_tries" == "forever" ]]; then
> > + continue
> > + fi
> > + let max_tries=$max_tries-1
> > + done
> > +
> > + if [[ $refcnt_is_zero -ne 1 ]]; then
> > + echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
> > + return -1
> > + fi
> > +
> > + # If we ran out of time but our refcnt check confirms we had
> > + # a refcnt of 0, just try to remove the module once.
> > + if [[ "$max_tries" == "0" ]]; then
>
> $max_tries -eq 0
Same issue.
Luis
On Wed, Aug 18, 2021 at 07:02:56AM -0700, Luis Chamberlain wrote:
> On Sun, Aug 15, 2021 at 08:29:42PM +0800, Eryu Guan wrote:
> > On Wed, Aug 11, 2021 at 08:45:11AM -0700, Luis Chamberlain wrote:
> > > common/config | 31 +++++++++++++++
> > > common/module | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >
> > Please also update README to document the new configurable variables.
>
> Got it.
>
> > > 2 files changed, 138 insertions(+)
> > >
> > > diff --git a/common/config b/common/config
> > > index 005fd50a..9b8a2bc4 100644
> > > --- a/common/config
> > > +++ b/common/config
> >
> > 100s as default seems a bit long to me, use 10s as in v1 patch?
>
> In practice I tried using 10s and from my observations we *still* ran
> into false positives. So from my own testing peace of mind I'd prefer at
> least something higher, and if its going to be higher might as well go
> with something which at least makes painfully safe. I'll go with 50s
> for my next submission.
>
> > > + fi
> > > +else
> > > + MODPROBE_RM_PATIENT_TIMEOUT_ARGS=""
> > > + if [[ ! -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
> > > + if [[ "$MODPROBE_PATIENT_RM_TIMEOUT_MS" != "forever" ]]; then
> >
> > Should check MODPROBE_PATIENT_RM_TIMEOUT_SECONDS instead?
>
> Indeed will fix.
>
> > > diff --git a/common/module b/common/module
> > > index 39e4e793..03953fa1 100644
> > > --- a/common/module
> > > +++ b/common/module
> > > @@ -4,6 +4,8 @@
> > > #
> > > # Routines for messing around with loadable kernel modules
> > >
> > > +source common/config
> > > +
> >
> > Seems there's no need to source common/config here, as it's sourced in
> > common/rc, which is sourced by every test.
>
> OK.
>
> > > + local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
> <-- snip -->
>
> > > + local max_tries=0
> <-- snip -->
>
> > > + max_tries=$max_tries_max
> > > +
> > > + while [[ "$max_tries" != "0" ]]; do
> >
> > Use "$max_tries -ne 0" to check inters seems better.
>
> max_tries can be "forever", in which case this is -eq 0:
>
> $ foo="forever"; if [[ $foo -eq 0 ]]; then echo buggy; else echo ok; fi
> buggy
I see, that makes sense. Then perhaps some comments would help.
Thanks,
Eryu
>
> > > + refcnt_is_zero=1
> > > + break
> > > + fi
> > > + sleep 1
> > > + if [[ "$max_tries" == "forever" ]]; then
> > > + continue
> > > + fi
> > > + let max_tries=$max_tries-1
> > > + done
> > > +
> > > + if [[ $refcnt_is_zero -ne 1 ]]; then
> > > + echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
> > > + return -1
> > > + fi
> > > +
> > > + # If we ran out of time but our refcnt check confirms we had
> > > + # a refcnt of 0, just try to remove the module once.
> > > + if [[ "$max_tries" == "0" ]]; then
> >
> > $max_tries -eq 0
>
> Same issue.
>
> Luis
On Thu, Aug 19, 2021 at 10:26:44AM +0800, Eryu Guan wrote:
> On Wed, Aug 18, 2021 at 07:02:56AM -0700, Luis Chamberlain wrote:
> > On Sun, Aug 15, 2021 at 08:29:42PM +0800, Eryu Guan wrote:
> > >
> > > Use "$max_tries -ne 0" to check inters seems better.
> >
> > max_tries can be "forever", in which case this is -eq 0:
> >
> > $ foo="forever"; if [[ $foo -eq 0 ]]; then echo buggy; else echo ok; fi
> > buggy
>
> I see, that makes sense. Then perhaps some comments would help.
I had sent out a v3 before seeing this request. I'll send a v4 with
a comment clarifying this.
Luis