[Devel] [PATCH vz9/vz10] dm-ploop: Fix file handle leaks when merging deltas

[Vasileios Almpanis]

When merging deltas, we rewrite the deltas array and remove the lower
delta. Each delta holds file handles for its runners, but these were not
being released. On vStorage, the files were deleted but a
temporary handle remained, causing EBUSY errors until reboot. As a
result, directories containing snapshots could not be deleted.

https://virtuozzo.atlassian.net/browse/VSTOR-116285

Signed-off-by: Vasileios Almpanis <vasileios.almpanis at virtuozzo.com>
Feature: dm-ploop: ploop target driver
---
 drivers/md/dm-ploop-cmd.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 2043162164be..1975f782be3c 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -725,7 +725,7 @@ static int ploop_merge_latest_snapshot(struct ploop *ploop)
 {
 	struct file *file;
 	u8 level;
-	int ret;
+	int ret, i;
 
 	if (ploop->maintaince)
 		return -EBUSY;
@@ -745,6 +745,15 @@ static int ploop_merge_latest_snapshot(struct ploop *ploop)
 
 	level = ploop->nr_deltas - 2;
 	file = ploop->deltas[level].file;
+
+	if (ploop->deltas[level].mtfile) {
+		for (i = 0; i < ploop->nkt_runners; i++) {
+			if (ploop->deltas[level].mtfile[i])
+				fput(ploop->deltas[level].mtfile[i]);
+		}
+		kfree(ploop->deltas[level].mtfile);
+	}
+
 	ploop->deltas[level] = ploop->deltas[level + 1];
 	ploop->nr_deltas--;
 	fput(file);
@@ -818,6 +827,15 @@ static void notify_delta_merged(struct ploop *ploop, u8 level,
 	}
 
 	file = ploop->deltas[level].file;
+
+	if (ploop->deltas[level].mtfile) {
+		for (i = 0; i < ploop->nkt_runners; i++) {
+			if (ploop->deltas[level].mtfile[i])
+				fput(ploop->deltas[level].mtfile[i]);
+		}
+		kfree(ploop->deltas[level].mtfile);
+	}
+
 	/* Renumber deltas above @level */
 	for (i = level + 1; i < ploop->nr_deltas; i++)
 		ploop->deltas[i - 1] = ploop->deltas[i];
-- 
2.43.0