locks: keep ref on the inode while locks are held

keeping refs on the inode while there are held locks prevents the
inode from getting pruned away

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 112 (parallel deletion of files mounted by different clients on the same back-end hangs and/or does not completely delete)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=112

5 files changed, 58 insertions, 0 deletions

diff --git a/xlators/features/locks/src/common.c b/xlators/features/locks/src/common.c
index 5f115f6fa53..11841e92d07 100644
--- a/xlators/features/locks/src/common.c
+++ b/xlators/features/locks/src/common.c
@@ -35,6 +35,7 @@
 #include "common-utils.h"
 
 #include "locks.h"
+#include "common.h"
 
 
 static int
@@ -48,6 +49,53 @@ __insert_and_merge (pl_inode_t *pl_inode, posix_lock_t *lock,
 				    ? &pl_inode->ext_list	\
 				    : &pl_inode->int_list)
 
+
+int
+__pl_inode_is_empty (pl_inode_t *pl_inode)
+{
+        int is_empty = 1;
+
+        if (!list_empty (&pl_inode->ext_list))
+                is_empty = 0;
+
+        if (!list_empty (&pl_inode->int_list))
+                is_empty = 0;
+
+        if (!list_empty (&pl_inode->dir_list))
+                is_empty = 0;
+
+        return is_empty;
+}
+
+void
+pl_update_refkeeper (xlator_t *this, inode_t *inode)
+{
+        pl_inode_t *pl_inode  = NULL;
+        int         is_empty  = 0;
+        int         need_unref = 0;
+
+        pl_inode = pl_inode_get (this, inode);
+
+        pthread_mutex_lock (&pl_inode->mutex);
+        {
+                is_empty = __pl_inode_is_empty (pl_inode);
+
+                if (is_empty && pl_inode->refkeeper) {
+                        need_unref = 1;
+                        pl_inode->refkeeper = NULL;
+                }
+
+                if (!is_empty && !pl_inode->refkeeper) {
+                        pl_inode->refkeeper = inode_ref (inode);
+                }
+        }
+        pthread_mutex_unlock (&pl_inode->mutex);
+
+        if (need_unref)
+                inode_unref (inode);
+}
+
+
 pl_inode_t *
 pl_inode_get (xlator_t *this, inode_t *inode)
 {
diff --git a/xlators/features/locks/src/common.h b/xlators/features/locks/src/common.h
index 06f104f5234..78de8432fad 100644
--- a/xlators/features/locks/src/common.h
+++ b/xlators/features/locks/src/common.h
@@ -49,4 +49,6 @@ void __delete_lock (pl_inode_t *, posix_lock_t *);
 
 void __destroy_lock (posix_lock_t *);
 
+void pl_update_refkeeper (xlator_t *this, inode_t *inode);
+
 #endif /* __COMMON_H__ */
diff --git a/xlators/features/locks/src/internal.c b/xlators/features/locks/src/internal.c
index 1c122093162..4878265871f 100644
--- a/xlators/features/locks/src/internal.c
+++ b/xlators/features/locks/src/internal.c
@@ -191,6 +191,7 @@ pl_inodelk (call_frame_t *frame, xlator_t *this,
 	op_ret = 0;
 
 unwind:	
+        pl_update_refkeeper (this, loc->inode);
 	STACK_UNWIND (frame, op_ret, op_errno);
 out:
 	return 0;
@@ -293,6 +294,7 @@ pl_finodelk (call_frame_t *frame, xlator_t *this,
 	op_ret = 0;
 
 unwind:	
+        pl_update_refkeeper (this, fd->inode);
 	STACK_UNWIND (frame, op_ret, op_errno);
 out:
 	return 0;
@@ -782,6 +784,7 @@ pl_entrylk (call_frame_t *frame, xlator_t *this,
 
 	op_ret = 0;
 out:
+        pl_update_refkeeper (this, loc->inode);
 	if (unwind) {
 		STACK_UNWIND (frame, op_ret, op_errno);
 	}
@@ -888,6 +891,7 @@ pl_fentrylk (call_frame_t *frame, xlator_t *this,
 
 	op_ret = 0;
 out:
+        pl_update_refkeeper (this, fd->inode);
 	if (unwind) {
 		STACK_UNWIND (frame, op_ret, op_errno);
 	}
diff --git a/xlators/features/locks/src/locks.h b/xlators/features/locks/src/locks.h
index 65da3a3650a..fe1333504ad 100644
--- a/xlators/features/locks/src/locks.h
+++ b/xlators/features/locks/src/locks.h
@@ -89,6 +89,9 @@ struct __pl_inode {
 	struct list_head int_list;       /* list of internal locks */
 	struct list_head rw_list;        /* list of waiting r/w requests */
 	int              mandatory;      /* if mandatory locking is enabled */
+
+        inode_t          *refkeeper;     /* hold refs on an inode while locks are
+                                            held to prevent pruning */
 };
 typedef struct __pl_inode pl_inode_t;
 
diff --git a/xlators/features/locks/src/posix.c b/xlators/features/locks/src/posix.c
index f963d5c9316..b1eb7e43518 100644
--- a/xlators/features/locks/src/posix.c
+++ b/xlators/features/locks/src/posix.c
@@ -687,6 +687,7 @@ pl_lk (call_frame_t *frame, xlator_t *this,
 	}
 
 unwind:
+        pl_update_refkeeper (this, fd->inode);
 	STACK_UNWIND (frame, op_ret, op_errno, flock);
 out:
 	return 0;