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-rw-r--r--xlators/features/locks/src/inodelk.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/xlators/features/locks/src/inodelk.c b/xlators/features/locks/src/inodelk.c
index ef06531cfde..9860e9f9079 100644
--- a/xlators/features/locks/src/inodelk.c
+++ b/xlators/features/locks/src/inodelk.c
@@ -224,6 +224,18 @@ __lock_inodelk (xlator_t *this, pl_inode_t *pl_inode, pl_inode_lock_t *lock,
goto out;
}
+ /* To prevent blocked locks starvation, check if there are any blocked
+ * locks thay may conflict with this lock. If there is then don't grant
+ * the lock. BUT grant the lock if the owner already has lock to allow
+ * nested locks.
+ * Example:
+ * SHD from Machine1 takes (gfid, 0-infinity) and is granted.
+ * SHD from machine2 takes (gfid, 0-infinity) and is blocked.
+ * When SHD from Machine1 takes (gfid, 0-128KB) it
+ * needs to be granted, without which the earlier lock on 0-infinity
+ * will not be unlocked by SHD from Machine1.
+ * TODO: Find why 'owner_has_lock' is checked even for blocked locks.
+ */
if (__blocked_lock_conflict (dom, lock) && !(__owner_has_lock (dom, lock))) {
ret = -EAGAIN;
if (can_block == 0)