From 573f0d46cff15fff2804b3fb444d1e34f482e788 Mon Sep 17 00:00:00 2001 From: Vishal Verma Date: Tue, 30 Mar 2021 20:54:55 -0600 Subject: [PATCH 016/217] libndctl: check for active system-ram before disabling daxctl devices Teach ndctl_namespace_disable_safe() to look at the state of a daxctl_dev with respect to whether it is active in 'system-ram' mode before disabling it. This is similar to checking whether a filesystem is actively mounted on a namespace before disabling it. Without this, libndctl would happily disable a devdax namespace while the device was active in system-ram mode. If the namespace was subsequently also destroyed, this would leave the memory without any sort of a 'handle' to perform any subsequent operation on it, and the system would have to be rebooted to get out of this situation. Reported-by: Chunye Xu Cc: Dan Williams Cc: Dave Hansen Signed-off-by: Vishal Verma --- ndctl/lib/libndctl.c | 25 ++++++++++++++++++++++++- test/daxctl-devices.sh | 16 ++++++++++++++++ 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c index 2f6d806..2eda56c 100644 --- a/ndctl/lib/libndctl.c +++ b/ndctl/lib/libndctl.c @@ -4593,21 +4593,40 @@ NDCTL_EXPORT int ndctl_namespace_disable_invalidate(struct ndctl_namespace *ndns return ndctl_namespace_disable(ndns); } +static int ndctl_dax_has_active_memory(struct ndctl_dax *dax) +{ + struct daxctl_region *dax_region; + struct daxctl_dev *dax_dev; + + dax_region = ndctl_dax_get_daxctl_region(dax); + if (!dax_region) + return 0; + + daxctl_dev_foreach(dax_region, dax_dev) + if (daxctl_dev_has_online_memory(dax_dev)) + return 1; + + return 0; +} + NDCTL_EXPORT int ndctl_namespace_disable_safe(struct ndctl_namespace *ndns) { const char *devname = ndctl_namespace_get_devname(ndns); struct ndctl_ctx *ctx = ndctl_namespace_get_ctx(ndns); struct ndctl_pfn *pfn = ndctl_namespace_get_pfn(ndns); struct ndctl_btt *btt = ndctl_namespace_get_btt(ndns); + struct ndctl_dax *dax = ndctl_namespace_get_dax(ndns); const char *bdev = NULL; + int fd, active = 0; char path[50]; - int fd; unsigned long long size = ndctl_namespace_get_size(ndns); if (pfn && ndctl_pfn_is_enabled(pfn)) bdev = ndctl_pfn_get_block_device(pfn); else if (btt && ndctl_btt_is_enabled(btt)) bdev = ndctl_btt_get_block_device(btt); + else if (dax && ndctl_dax_is_enabled(dax)) + active = ndctl_dax_has_active_memory(dax); else if (ndctl_namespace_is_enabled(ndns)) bdev = ndctl_namespace_get_block_device(ndns); @@ -4632,6 +4651,10 @@ NDCTL_EXPORT int ndctl_namespace_disable_safe(struct ndctl_namespace *ndns) devname, bdev, strerror(errno)); return -errno; } + } else if (active) { + dbg(ctx, "%s: active as system-ram, refusing to disable\n", + devname); + return -EBUSY; } else { if (size == 0) /* No disable necessary due to no capacity allocated */ diff --git a/test/daxctl-devices.sh b/test/daxctl-devices.sh index eed5906..56c9691 100755 --- a/test/daxctl-devices.sh +++ b/test/daxctl-devices.sh @@ -105,6 +105,22 @@ daxctl_test() "$DAXCTL" reconfigure-device -f -m devdax "$daxdev" [[ $(daxctl_get_mode "$daxdev") == "devdax" ]] + # fail 'ndctl-disable-namespace' while the devdax namespace is active + # as system-ram. If this test fails, a reboot will be required to + # recover from the resulting state. + test -n "$testdev" + "$DAXCTL" reconfigure-device -m system-ram "$daxdev" + [[ $(daxctl_get_mode "$daxdev") == "system-ram" ]] + if ! "$NDCTL" disable-namespace "$testdev"; then + echo "disable-namespace failed as expected" + else + echo "disable-namespace succeded, expected failure" + echo "reboot required to recover from this state" + return 1 + fi + "$DAXCTL" reconfigure-device -f -m devdax "$daxdev" + [[ $(daxctl_get_mode "$daxdev") == "devdax" ]] + # this tests for reconfiguration failure if an online-policy is set set_online_policy : "This command is expected to fail:" -- 2.27.0