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authorAlex Elder <elder@inktank.com>2013-04-30 00:44:32 -0500
committerSage Weil <sage@inktank.com>2013-05-01 21:20:08 -0700
commit4f0dcb10cf1454a1c38aeaa04cb2757535e4905e (patch)
tree1637c6a8961c95bdf02b7326cea79ca9b0b8e07f /net/ceph
parentb536f69a3a589113992c32982bf2981c8225c9da (diff)
libceph: create source file "net/ceph/snapshot.c"
This creates a new source file "net/ceph/snapshot.c" to contain utility routines related to ceph snapshot contexts. The main motivation was to define ceph_create_snap_context() as a common way to create these structures, but I've moved the definitions of ceph_get_snap_context() and ceph_put_snap_context() there too. (The benefit of inlining those is very small, and I'd rather keep this collection of functions together.) Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Diffstat (limited to 'net/ceph')
-rw-r--r--net/ceph/Makefile2
-rw-r--r--net/ceph/snapshot.c78
2 files changed, 79 insertions, 1 deletions
diff --git a/net/ceph/Makefile b/net/ceph/Makefile
index e87ef435e11b..958d9856912c 100644
--- a/net/ceph/Makefile
+++ b/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/net/ceph/snapshot.c b/net/ceph/snapshot.c
new file mode 100644
index 000000000000..154683f5f14c
--- /dev/null
+++ b/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);

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