[linux-lvm] [PATCH] [PATCH] stable-2.02 - lvresize: deny operation on swap dev without force option

[Zhao Heming <heming.zhao@suse.com>]

When lvmetad is active on system and some memory pages of lvmetad
swapout, user may issue lvextend/lvresize on swap LV. The resize
operation will suspend & resume swap device (by reload dm table).
After suspended swap device, lvmetad will be in UN status for waiting
swapin pages from suspended swap dev. lvmetad will hung, then
lvresize will fail to conection to lvmetad. then the resize operation
will fail, lvresize leaves suspended swap, the logic dead lock is
happending.

This commit add "--force" checking for lvresize on swap device. The
"--force" and related error info make user to understand swap device
should be deactive when resizing.

Signed-off-by: Zhao Heming <heming.zhao@suse.com>
---
 lib/device/dev-swap.c   | 19 +++++++++++++++++++
 lib/device/dev-type.h   |  1 +
 lib/metadata/lv_manip.c |  9 +++++++++
 3 files changed, 29 insertions(+)

diff --git a/lib/device/dev-swap.c b/lib/device/dev-swap.c
index 3bfb72b38ce6..a65e75b06157 100644
--- a/lib/device/dev-swap.c
+++ b/lib/device/dev-swap.c
@@ -14,6 +14,7 @@
 
 #include "lib.h"
 #include "dev-type.h"
+#include "dev-cache.h"
 
 #ifdef __linux__
 
@@ -73,4 +74,22 @@ int dev_is_swap(struct device *dev, uint64_t *offset_found, int full)
 	return ret;
 }
 
+/* User may set up swap LV with complex underlying devs. */
+int lv_is_swap(struct logical_volume *lv, int *is_swap)
+{
+	struct device *dev;
+	struct dev_iter *iter;
+
+	if (!(iter = dev_iter_create(NULL, 1)))
+		return_0;
+
+	*is_swap = 0;
+	while ((dev = dev_iter_get(iter))) {
+		*is_swap |= dev_is_swap(dev, NULL, 1);
+	}
+	dev_iter_destroy(iter);
+
+	return 1;
+}
+
 #endif
diff --git a/lib/device/dev-type.h b/lib/device/dev-type.h
index bd989f8c8a2a..bbf6c0f1efad 100644
--- a/lib/device/dev-type.h
+++ b/lib/device/dev-type.h
@@ -63,6 +63,7 @@ int dev_is_luks(struct device *dev, uint64_t *signature, int full);
 int dasd_is_cdl_formatted(struct device *dev);
 int udev_dev_is_mpath_component(struct device *dev);
 int udev_dev_is_md_component(struct device *dev);
+int lv_is_swap(struct logical_volume *lv, int *is_swap);
 
 int dev_is_lvm1(struct device *dev, char *buf, int buflen);
 int dev_is_pool(struct device *dev, char *buf, int buflen);
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 0918780f143c..c099db8419b0 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -4830,6 +4830,7 @@ static int _lvresize_check(struct logical_volume *lv,
 {
 	struct volume_group *vg = lv->vg;
 	struct lv_segment *seg = first_seg(lv);
+	int is_swap;
 
 	if (lv_is_external_origin(lv)) {
 		/*
@@ -4927,6 +4928,14 @@ static int _lvresize_check(struct logical_volume *lv,
 		return 0;
 	}
 
+	if (lv_is_swap(lv, &is_swap)) {
+		if (is_swap && !lp->force) {
+			log_error("LV is a swap device, and command without --force option.");
+			log_error("Please make sure swap is DEACTIVE and re-run with --force option.");
+			return 0;
+		}
+	}
+
 	return 1;
 }
 
-- 
2.26.2

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