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author | Alex Elder <elder@inktank.com> | 2013-04-30 05:44:32 (GMT) |
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committer | Sage Weil <sage@inktank.com> | 2013-05-02 04:20:08 (GMT) |
commit | 4f0dcb10cf1454a1c38aeaa04cb2757535e4905e (patch) | |
tree | 1637c6a8961c95bdf02b7326cea79ca9b0b8e07f /net/ceph/snapshot.c | |
parent | b536f69a3a589113992c32982bf2981c8225c9da (diff) | |
download | linux-fsl-qoriq-4f0dcb10cf1454a1c38aeaa04cb2757535e4905e.tar.xz |
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/snapshot.c')
-rw-r--r-- | net/ceph/snapshot.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/net/ceph/snapshot.c b/net/ceph/snapshot.c new file mode 100644 index 0000000..154683f --- /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); |