linux-stable/drivers/block/rbd_types.h

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/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2010 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_RBD_TYPES_H
#define CEPH_RBD_TYPES_H
#include <linux/types.h>
/* For format version 2, rbd image 'foo' consists of objects
* rbd_id.foo - id of image
* rbd_header.<id> - image metadata
* rbd_object_map.<id> - optional image object map
* rbd_data.<id>.0000000000000000
* rbd_data.<id>.0000000000000001
* ... - data
* Clients do not access header data directly in rbd format 2.
*/
#define RBD_HEADER_PREFIX "rbd_header."
#define RBD_OBJECT_MAP_PREFIX "rbd_object_map."
#define RBD_ID_PREFIX "rbd_id."
#define RBD_V2_DATA_FORMAT "%s.%016llx"
#define RBD_LOCK_NAME "rbd_lock"
#define RBD_LOCK_TAG "internal"
#define RBD_LOCK_COOKIE_PREFIX "auto"
enum rbd_notify_op {
RBD_NOTIFY_OP_ACQUIRED_LOCK = 0,
RBD_NOTIFY_OP_RELEASED_LOCK = 1,
RBD_NOTIFY_OP_REQUEST_LOCK = 2,
RBD_NOTIFY_OP_HEADER_UPDATE = 3,
};
#define OBJECT_NONEXISTENT 0
#define OBJECT_EXISTS 1
#define OBJECT_PENDING 2
#define OBJECT_EXISTS_CLEAN 3
#define RBD_FLAG_OBJECT_MAP_INVALID (1ULL << 0)
#define RBD_FLAG_FAST_DIFF_INVALID (1ULL << 1)
/*
* For format version 1, rbd image 'foo' consists of objects
* foo.rbd - image metadata
* rb.<idhi>.<idlo>.<extra>.000000000000
* rb.<idhi>.<idlo>.<extra>.000000000001
* ... - data
* There is no notion of a persistent image id in rbd format 1.
*/
#define RBD_SUFFIX ".rbd"
#define RBD_V1_DATA_FORMAT "%s.%012llx"
#define RBD_DIRECTORY "rbd_directory"
#define RBD_INFO "rbd_info"
#define RBD_DEFAULT_OBJ_ORDER 22 /* 4MB */
#define RBD_MIN_OBJ_ORDER 16
#define RBD_MAX_OBJ_ORDER 30
#define RBD_HEADER_TEXT "<<< Rados Block Device Image >>>\n"
#define RBD_HEADER_SIGNATURE "RBD"
#define RBD_HEADER_VERSION "001.005"
struct rbd_image_snap_ondisk {
__le64 id;
__le64 image_size;
} __attribute__((packed));
struct rbd_image_header_ondisk {
char text[40];
char object_prefix[24];
char signature[4];
char version[8];
struct {
__u8 order;
__u8 crypt_type;
__u8 comp_type;
__u8 unused;
} __attribute__((packed)) options;
__le64 image_size;
__le64 snap_seq;
__le32 snap_count;
__le32 reserved;
__le64 snap_names_len;
libceph, rbd: replace zero-length array with flexible-array The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2020-05-07 18:51:38 +00:00
struct rbd_image_snap_ondisk snaps[];
} __attribute__((packed));
#endif