projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 4f0dcb10 AE |
1 | /* |
| 2 | * snapshot.c Ceph snapshot context utility routines (part of libceph) | |
| 3 | * | |
| 4 | * Copyright (C) 2013 Inktank Storage, Inc. | |
| 5 | * | |
| 6 | * This program is free software; you can redistribute it and/or | |
| 7 | * modify it under the terms of the GNU General Public License | |
| 8 | * version 2 as published by the Free Software Foundation. | |
| 9 | * | |
| 10 | * This program is distributed in the hope that it will be useful, | |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | * General Public License for more details. | |
| 14 | * | |
| 15 | * You should have received a copy of the GNU General Public License | |
| 16 | * along with this program; if not, write to the Free Software | |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
| 18 | * 02110-1301, USA. | |
| 19 | */ | |
| 20 | ||
| 21 | #include <stddef.h> | |
| 22 | ||
| 23 | #include <linux/types.h> | |
| 24 | #include <linux/export.h> | |
| 25 | #include <linux/ceph/libceph.h> | |
| 26 | ||
| 27 | /* | |
| 28 | * Ceph snapshot contexts are reference counted objects, and the | |
| 29 | * returned structure holds a single reference. Acquire additional | |
| 30 | * references with ceph_get_snap_context(), and release them with | |
| 31 | * ceph_put_snap_context(). When the reference count reaches zero | |
| 32 | * the entire structure is freed. | |
| 33 | */ | |
| 34 | ||
| 35 | /* | |
| 36 | * Create a new ceph snapshot context large enough to hold the | |
| 37 | * indicated number of snapshot ids (which can be 0). Caller has | |
| 38 | * to fill in snapc->seq and snapc->snaps[0..snap_count-1]. | |
| 39 | * | |
| 40 | * Returns a null pointer if an error occurs. | |
| 41 | */ | |
| 42 | struct ceph_snap_context *ceph_create_snap_context(u32 snap_count, | |
| 43 | gfp_t gfp_flags) | |
| 44 | { | |
| 45 | struct ceph_snap_context *snapc; | |
| 46 | size_t size; | |
| 47 | ||
| 48 | size = sizeof (struct ceph_snap_context); | |
| 49 | size += snap_count * sizeof (snapc->snaps[0]); | |
| 50 | snapc = kzalloc(size, gfp_flags); | |
| 51 | if (!snapc) | |
| 52 | return NULL; | |
| 53 | ||
| 54 | atomic_set(&snapc->nref, 1); | |
| 55 | snapc->num_snaps = snap_count; | |
| 56 | ||
| 57 | return snapc; | |
| 58 | } | |
| 59 | EXPORT_SYMBOL(ceph_create_snap_context); | |
| 60 | ||
| 61 | struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc) | |
| 62 | { | |
| 63 | if (sc) | |
| 64 | atomic_inc(&sc->nref); | |
| 65 | return sc; | |
| 66 | } | |
| 67 | EXPORT_SYMBOL(ceph_get_snap_context); | |
| 68 | ||
| 69 | void ceph_put_snap_context(struct ceph_snap_context *sc) | |
| 70 | { | |
| 71 | if (!sc) | |
| 72 | return; | |
| 73 | if (atomic_dec_and_test(&sc->nref)) { | |
| 74 | /*printk(" deleting snap_context %p\n", sc);*/ | |
| 75 | kfree(sc); | |
| 76 | } | |
| 77 | } | |
| 78 | EXPORT_SYMBOL(ceph_put_snap_context); |