From e51f7972c4622d4ae1474045143ce0193db1155f Mon Sep 17 00:00:00 2001
From: Alex Elder <elder@inktank.com>
Date: Tue, 30 Apr 2013 00:44:32 -0500
Subject: [PATCH] --- yaml --- r: 373527 b: refs/heads/master c:
 4f0dcb10cf1454a1c38aeaa04cb2757535e4905e h: refs/heads/master i:   373525:
 1baaaf4c4fb4f2fcebd20af76fa636eaa45095d2   373523:
 e2ccaaafb0a37d1f18b1659b910e8819596cf8fa   373519:
 bdf2b26edf817c661f997fdb58bb15d07cec7e12 v: v3

---
 [refs]                             |  2 +-
 trunk/include/linux/ceph/libceph.h | 30 ++----------
 trunk/net/ceph/Makefile            |  2 +-
 trunk/net/ceph/snapshot.c          | 78 ++++++++++++++++++++++++++++++
 4 files changed, 85 insertions(+), 27 deletions(-)
 create mode 100644 trunk/net/ceph/snapshot.c

diff --git a/[refs] b/[refs]
index 6e4bc7d98bd6..7dd00b1a398d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b536f69a3a589113992c32982bf2981c8225c9da
+refs/heads/master: 4f0dcb10cf1454a1c38aeaa04cb2757535e4905e
diff --git a/trunk/include/linux/ceph/libceph.h b/trunk/include/linux/ceph/libceph.h
index 5493d7b86423..2e3024881a5e 100644
--- a/trunk/include/linux/ceph/libceph.h
+++ b/trunk/include/linux/ceph/libceph.h
@@ -157,31 +157,11 @@ struct ceph_snap_context {
 	u64 snaps[];
 };
 
-static inline struct ceph_snap_context *
-ceph_get_snap_context(struct ceph_snap_context *sc)
-{
-	/*
-	printk("get_snap_context %p %d -> %d\n", sc, atomic_read(&sc->nref),
-	       atomic_read(&sc->nref)+1);
-	*/
-	if (sc)
-		atomic_inc(&sc->nref);
-	return sc;
-}
-
-static inline void ceph_put_snap_context(struct ceph_snap_context *sc)
-{
-	if (!sc)
-		return;
-	/*
-	printk("put_snap_context %p %d -> %d\n", sc, atomic_read(&sc->nref),
-	       atomic_read(&sc->nref)-1);
-	*/
-	if (atomic_dec_and_test(&sc->nref)) {
-		/*printk(" deleting snap_context %p\n", sc);*/
-		kfree(sc);
-	}
-}
+extern struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
+					gfp_t gfp_flags);
+extern struct ceph_snap_context *ceph_get_snap_context(
+					struct ceph_snap_context *sc);
+extern void ceph_put_snap_context(struct ceph_snap_context *sc);
 
 /*
  * calculate the number of pages a given length and offset map onto,
diff --git a/trunk/net/ceph/Makefile b/trunk/net/ceph/Makefile
index e87ef435e11b..958d9856912c 100644
--- a/trunk/net/ceph/Makefile
+++ b/trunk/net/ceph/Makefile
@@ -11,5 +11,5 @@ libceph-y := ceph_common.o messenger.o msgpool.o buffer.o pagelist.o \
 	crypto.o armor.o \
 	auth_x.o \
 	ceph_fs.o ceph_strings.o ceph_hash.o \
-	pagevec.o
+	pagevec.o snapshot.o
 
diff --git a/trunk/net/ceph/snapshot.c b/trunk/net/ceph/snapshot.c
new file mode 100644
index 000000000000..154683f5f14c
--- /dev/null
+++ b/trunk/net/ceph/snapshot.c
@@ -0,0 +1,78 @@
+/*
+ * snapshot.c    Ceph snapshot context utility routines (part of libceph)
+ *
+ * Copyright (C) 2013 Inktank Storage, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <stddef.h>
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/ceph/libceph.h>
+
+/*
+ * Ceph snapshot contexts are reference counted objects, and the
+ * returned structure holds a single reference.  Acquire additional
+ * references with ceph_get_snap_context(), and release them with
+ * ceph_put_snap_context().  When the reference count reaches zero
+ * the entire structure is freed.
+ */
+
+/*
+ * Create a new ceph snapshot context large enough to hold the
+ * indicated number of snapshot ids (which can be 0).  Caller has
+ * to fill in snapc->seq and snapc->snaps[0..snap_count-1].
+ *
+ * Returns a null pointer if an error occurs.
+ */
+struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
+						gfp_t gfp_flags)
+{
+	struct ceph_snap_context *snapc;
+	size_t size;
+
+	size = sizeof (struct ceph_snap_context);
+	size += snap_count * sizeof (snapc->snaps[0]);
+	snapc = kzalloc(size, gfp_flags);
+	if (!snapc)
+		return NULL;
+
+	atomic_set(&snapc->nref, 1);
+	snapc->num_snaps = snap_count;
+
+	return snapc;
+}
+EXPORT_SYMBOL(ceph_create_snap_context);
+
+struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
+{
+	if (sc)
+		atomic_inc(&sc->nref);
+	return sc;
+}
+EXPORT_SYMBOL(ceph_get_snap_context);
+
+void ceph_put_snap_context(struct ceph_snap_context *sc)
+{
+	if (!sc)
+		return;
+	if (atomic_dec_and_test(&sc->nref)) {
+		/*printk(" deleting snap_context %p\n", sc);*/
+		kfree(sc);
+	}
+}
+EXPORT_SYMBOL(ceph_put_snap_context);