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This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
Copyright (C) 1999-2008, Philipp Reisner <>.
Copyright (C) 2002-2008, Lars Ellenberg <>.
drbd is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
drbd is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with drbd; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
#ifndef _DRBD_INT_H
#define _DRBD_INT_H
#include <crypto/hash.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/sched/signal.h>
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/tcp.h>
#include <linux/mutex.h>
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/genhd.h>
#include <linux/idr.h>
#include <linux/dynamic_debug.h>
#include <net/tcp.h>
#include <linux/lru_cache.h>
#include <linux/prefetch.h>
#include <linux/drbd_genl_api.h>
#include <linux/drbd.h>
#include "drbd_strings.h"
#include "drbd_state.h"
#include "drbd_protocol.h"
#ifdef __CHECKER__
# define __protected_by(x) __attribute__((require_context(x,1,999,"rdwr")))
# define __protected_read_by(x) __attribute__((require_context(x,1,999,"read")))
# define __protected_write_by(x) __attribute__((require_context(x,1,999,"write")))
# define __must_hold(x) __attribute__((context(x,1,1), require_context(x,1,999,"call")))
# define __protected_by(x)
# define __protected_read_by(x)
# define __protected_write_by(x)
# define __must_hold(x)
/* shared module parameters, defined in drbd_main.c */
extern int drbd_enable_faults;
extern int drbd_fault_rate;
extern unsigned int drbd_minor_count;
extern char drbd_usermode_helper[];
extern int drbd_proc_details;
/* This is used to stop/restart our threads.
* Cannot use SIGTERM nor SIGKILL, since these
* are sent out by init on runlevel changes
* I choose SIGHUP for now.
#define ID_IN_SYNC (4711ULL)
#define ID_OUT_OF_SYNC (4712ULL)
#define ID_SYNCER (-1ULL)
#define UUID_NEW_BM_OFFSET ((u64)0x0001000000000000ULL)
struct drbd_device;
struct drbd_connection;
#define __drbd_printk_device(level, device, fmt, args...) \
dev_printk(level, disk_to_dev((device)->vdisk), fmt, ## args)
#define __drbd_printk_peer_device(level, peer_device, fmt, args...) \
dev_printk(level, disk_to_dev((peer_device)->device->vdisk), fmt, ## args)
#define __drbd_printk_resource(level, resource, fmt, args...) \
printk(level "drbd %s: " fmt, (resource)->name, ## args)
#define __drbd_printk_connection(level, connection, fmt, args...) \
printk(level "drbd %s: " fmt, (connection)->resource->name, ## args)
void drbd_printk_with_wrong_object_type(void);
#define __drbd_printk_if_same_type(obj, type, func, level, fmt, args...) \
(__builtin_types_compatible_p(typeof(obj), type) || \
__builtin_types_compatible_p(typeof(obj), const type)), \
func(level, (const type)(obj), fmt, ## args)
#define drbd_printk(level, obj, fmt, args...) \
__builtin_choose_expr( \
__drbd_printk_if_same_type(obj, struct drbd_device *, \
__drbd_printk_device, level, fmt, ## args), \
__builtin_choose_expr( \
__drbd_printk_if_same_type(obj, struct drbd_resource *, \
__drbd_printk_resource, level, fmt, ## args), \
__builtin_choose_expr( \
__drbd_printk_if_same_type(obj, struct drbd_connection *, \
__drbd_printk_connection, level, fmt, ## args), \
__builtin_choose_expr( \
__drbd_printk_if_same_type(obj, struct drbd_peer_device *, \
__drbd_printk_peer_device, level, fmt, ## args), \
#define drbd_dbg(obj, fmt, args...) \
drbd_printk(KERN_DEBUG, obj, fmt, ## args)
#define drbd_alert(obj, fmt, args...) \
drbd_printk(KERN_ALERT, obj, fmt, ## args)
#define drbd_err(obj, fmt, args...) \
drbd_printk(KERN_ERR, obj, fmt, ## args)
#define drbd_warn(obj, fmt, args...) \
drbd_printk(KERN_WARNING, obj, fmt, ## args)
#define drbd_info(obj, fmt, args...) \
drbd_printk(KERN_INFO, obj, fmt, ## args)
#define drbd_emerg(obj, fmt, args...) \
drbd_printk(KERN_EMERG, obj, fmt, ## args)
#define dynamic_drbd_dbg(device, fmt, args...) \
dynamic_dev_dbg(disk_to_dev(device->vdisk), fmt, ## args)
#define D_ASSERT(device, exp) do { \
if (!(exp)) \
drbd_err(device, "ASSERT( " #exp " ) in %s:%d\n", __FILE__, __LINE__); \
} while (0)
* expect - Make an assertion
* Unlike the assert macro, this macro returns a boolean result.
#define expect(exp) ({ \
bool _bool = (exp); \
if (!_bool) \
drbd_err(device, "ASSERTION %s FAILED in %s\n", \
#exp, __func__); \
_bool; \
/* Defines to control fault insertion */
enum {
DRBD_FAULT_MD_WR = 0, /* meta data write */
DRBD_FAULT_MD_RD = 1, /* read */
DRBD_FAULT_RS_WR = 2, /* resync */
DRBD_FAULT_DT_WR = 4, /* data */
DRBD_FAULT_DT_RA = 6, /* data read ahead */
DRBD_FAULT_BM_ALLOC = 7, /* bitmap allocation */
DRBD_FAULT_AL_EE = 8, /* alloc ee */
DRBD_FAULT_RECEIVE = 9, /* Changes some bytes upon receiving a [rs]data block */
extern unsigned int
_drbd_insert_fault(struct drbd_device *device, unsigned int type);
static inline int
drbd_insert_fault(struct drbd_device *device, unsigned int type) {
return drbd_fault_rate &&
(drbd_enable_faults & (1<<type)) &&
_drbd_insert_fault(device, type);
return 0;
/* integer division, round _UP_ to the next integer */
#define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
/* usual integer division */
#define div_floor(A, B) ((A)/(B))
extern struct ratelimit_state drbd_ratelimit_state;
extern struct idr drbd_devices; /* RCU, updates: genl_lock() */
extern struct list_head drbd_resources; /* RCU, updates: genl_lock() */
extern const char *cmdname(enum drbd_packet cmd);
/* for sending/receiving the bitmap,
* possibly in some encoding scheme */
struct bm_xfer_ctx {
/* "const"
* stores total bits and long words
* of the bitmap, so we don't need to
* call the accessor functions over and again. */
unsigned long bm_bits;
unsigned long bm_words;
/* during xfer, current position within the bitmap */
unsigned long bit_offset;
unsigned long word_offset;
/* statistics; index: (h->command == P_BITMAP) */
unsigned packets[2];
unsigned bytes[2];
extern void INFO_bm_xfer_stats(struct drbd_device *device,
const char *direction, struct bm_xfer_ctx *c);
static inline void bm_xfer_ctx_bit_to_word_offset(struct bm_xfer_ctx *c)
/* word_offset counts "native long words" (32 or 64 bit),
* aligned at 64 bit.
* Encoded packet may end at an unaligned bit offset.
* In case a fallback clear text packet is transmitted in
* between, we adjust this offset back to the last 64bit
* aligned "native long word", which makes coding and decoding
* the plain text bitmap much more convenient. */
#if BITS_PER_LONG == 64
c->word_offset = c->bit_offset >> 6;
#elif BITS_PER_LONG == 32
c->word_offset = c->bit_offset >> 5;
c->word_offset &= ~(1UL);
# error "unsupported BITS_PER_LONG"
extern unsigned int drbd_header_size(struct drbd_connection *connection);
enum drbd_thread_state {
struct drbd_thread {
spinlock_t t_lock;
struct task_struct *task;
struct completion stop;
enum drbd_thread_state t_state;
int (*function) (struct drbd_thread *);
struct drbd_resource *resource;
struct drbd_connection *connection;
int reset_cpu_mask;
const char *name;
static inline enum drbd_thread_state get_t_state(struct drbd_thread *thi)
/* THINK testing the t_state seems to be uncritical in all cases
* (but thread_{start,stop}), so we can read it *without* the lock.
* --lge */
return thi->t_state;
struct drbd_work {
struct list_head list;
int (*cb)(struct drbd_work *, int cancel);
struct drbd_device_work {
struct drbd_work w;
struct drbd_device *device;
#include "drbd_interval.h"
extern int drbd_wait_misc(struct drbd_device *, struct drbd_interval *);
extern void lock_all_resources(void);
extern void unlock_all_resources(void);
struct drbd_request {
struct drbd_work w;
struct drbd_device *device;
/* if local IO is not allowed, will be NULL.
* if local IO _is_ allowed, holds the locally submitted bio clone,
* or, after local IO completion, the ERR_PTR(error).
* see drbd_request_endio(). */
struct bio *private_bio;
struct drbd_interval i;
/* epoch: used to check on "completion" whether this req was in
* the current epoch, and we therefore have to close it,
* causing a p_barrier packet to be send, starting a new epoch.
* This corresponds to "barrier" in struct p_barrier[_ack],
* and to "barrier_nr" in struct drbd_epoch (and various
* comments/function parameters/local variable names).
unsigned int epoch;
struct list_head tl_requests; /* ring list in the transfer log */
struct bio *master_bio; /* master bio pointer */
/* see struct drbd_device */
struct list_head req_pending_master_completion;
struct list_head req_pending_local;
/* for generic IO accounting */
unsigned long start_jif;
/* for DRBD internal statistics */
/* Minimal set of time stamps to determine if we wait for activity log
* transactions, local disk or peer. 32 bit "jiffies" are good enough,
* we don't expect a DRBD request to be stalled for several month.
/* before actual request processing */
unsigned long in_actlog_jif;
/* local disk */
unsigned long pre_submit_jif;
/* per connection */
unsigned long pre_send_jif;
unsigned long acked_jif;
unsigned long net_done_jif;
/* Possibly even more detail to track each phase:
* master_completion_jif
* how long did it take to complete the master bio
* (application visible latency)
* allocated_jif
* how long the master bio was blocked until we finally allocated
* a tracking struct
* in_actlog_jif
* how long did we wait for activity log transactions
* net_queued_jif
* when did we finally queue it for sending
* pre_send_jif
* when did we start sending it
* post_send_jif
* how long did we block in the network stack trying to send it
* acked_jif
* when did we receive (or fake, in protocol A) a remote ACK
* net_done_jif
* when did we receive final acknowledgement (P_BARRIER_ACK),
* or decide, e.g. on connection loss, that we do no longer expect
* anything from this peer for this request.
* pre_submit_jif
* post_sub_jif
* when did we start submiting to the lower level device,
* and how long did we block in that submit function
* local_completion_jif
* how long did it take the lower level device to complete this request
/* once it hits 0, we may complete the master_bio */
atomic_t completion_ref;
/* once it hits 0, we may destroy this drbd_request object */
struct kref kref;
unsigned rq_state; /* see comments above _req_mod() */
struct drbd_epoch {
struct drbd_connection *connection;
struct list_head list;
unsigned int barrier_nr;
atomic_t epoch_size; /* increased on every request added. */
atomic_t active; /* increased on every req. added, and dec on every finished. */
unsigned long flags;
/* Prototype declaration of function defined in drbd_receiver.c */
int drbdd_init(struct drbd_thread *);
int drbd_asender(struct drbd_thread *);
/* drbd_epoch flag bits */
enum {
enum epoch_event {
EV_CLEANUP = 32, /* used as flag */
struct digest_info {
int digest_size;
void *digest;
struct drbd_peer_request {
struct drbd_work w;
struct drbd_peer_device *peer_device;
struct drbd_epoch *epoch; /* for writes */
struct page *pages;
atomic_t pending_bios;
struct drbd_interval i;
/* see comments on ee flag bits below */
unsigned long flags;
unsigned long submit_jif;
union {
u64 block_id;
struct digest_info *digest;
/* ee flag bits.
* While corresponding bios are in flight, the only modification will be
* set_bit WAS_ERROR, which has to be atomic.
* If no bios are in flight yet, or all have been completed,
* non-atomic modification to ee->flags is ok.
enum {
/* is this a TRIM aka REQ_DISCARD? */
/* In case a barrier failed,
* we need to resubmit without the barrier flag. */
/* we may have several bios per peer request.
* if any of those fail, we set this flag atomically
* from the endio callback */
/* This ee has a pointer to a digest instead of a block id */
/* Conflicting local requests need to be restarted after this request */
/* The peer wants a write ACK for this (wire proto C) */
/* Is set when net_conf had two_primaries set while creating this peer_req */
/* for debugfs: */
/* has this been submitted, or does it still wait for something else? */
/* this is/was a write request */
/* this is/was a write same request */
/* this originates from application on peer
* (not some resync or verify or other DRBD internal request) */
/* If it contains only 0 bytes, send back P_RS_DEALLOCATED */
#define EE_IS_TRIM (1<<__EE_IS_TRIM)
#define EE_WAS_ERROR (1<<__EE_WAS_ERROR)
#define EE_WRITE (1<<__EE_WRITE)
#define EE_RS_THIN_REQ (1<<__EE_RS_THIN_REQ)
/* flag bits per device */
enum {
UNPLUG_REMOTE, /* sending a "UnplugRemote" could help */
MD_DIRTY, /* current uuids and flags not yet on disk */
USE_DEGR_WFC_T, /* degr-wfc-timeout instead of wfc-timeout. */
CRASHED_PRIMARY, /* This node was a crashed primary.
* Gets cleared when the state.conn
* goes into C_CONNECTED state. */
MD_NO_FUA, /* Users wants us to not use FUA/FLUSH on meta data dev */
BITMAP_IO, /* suspend application io;
once no more io in flight, start bitmap io */
BITMAP_IO_QUEUED, /* Started bitmap IO */
WAS_IO_ERROR, /* Local disk failed, returned IO error */
WAS_READ_ERROR, /* Local disk READ failed (set additionally to the above) */
FORCE_DETACH, /* Force-detach from local disk, aborting any pending local IO */
RESYNC_AFTER_NEG, /* Resync after online grow after the attach&negotiate finished. */
RESIZE_PENDING, /* Size change detected locally, waiting for the response from
* the peer, if it changed there as well. */
NEW_CUR_UUID, /* Create new current UUID when thawing IO */
AL_SUSPENDED, /* Activity logging is currently suspended. */
AHEAD_TO_SYNC_SOURCE, /* Ahead -> SyncSource queued */
B_RS_H_DONE, /* Before resync handler done (already executed) */
DISCARD_MY_DATA, /* discard_my_data flag per volume */
FLUSH_PENDING, /* if set, device->flush_jif is when we submitted that flush
* from drbd_flush_after_epoch() */
/* cleared only after backing device related structures have been destroyed. */
GOING_DISKLESS, /* Disk is being detached, because of io-error, or admin request. */
/* to be used in drbd_device_post_work() */
GO_DISKLESS, /* tell worker to schedule cleanup before detach */
DESTROY_DISK, /* tell worker to close backing devices and destroy related structures. */
MD_SYNC, /* tell worker to call drbd_md_sync() */
RS_START, /* tell worker to start resync/OV */
RS_PROGRESS, /* tell worker that resync made significant progress */
RS_DONE, /* tell worker that resync is done */
struct drbd_bitmap; /* opaque for drbd_device */
/* definition of bits in bm_flags to be used in drbd_bm_lock
* and drbd_bitmap_io and friends. */
enum bm_flag {
/* currently locked for bulk operation */
/* in detail, that is: */
BM_DONT_SET = 0x2,
/* so we can mark it locked for bulk operation,
* and still allow all non-bulk operations */
/* (test bit, count bit) allowed (common case) */
/* testing bits, as well as setting new bits allowed, but clearing bits
* would be unexpected. Used during bitmap receive. Setting new bits
* requires sending of "out-of-sync" information, though. */
/* for drbd_bm_write_copy_pages, everything is allowed,
* only concurrent bulk operations are locked out. */
struct drbd_work_queue {
struct list_head q;
spinlock_t q_lock; /* to protect the list. */
wait_queue_head_t q_wait;
struct drbd_socket {
struct mutex mutex;
struct socket *socket;
/* this way we get our
* send/receive buffers off the stack */
void *sbuf;
void *rbuf;
struct drbd_md {
u64 md_offset; /* sector offset to 'super' block */
u64 la_size_sect; /* last agreed size, unit sectors */
spinlock_t uuid_lock;
u64 uuid[UI_SIZE];
u64 device_uuid;
u32 flags;
u32 md_size_sect;
s32 al_offset; /* signed relative sector offset to activity log */
s32 bm_offset; /* signed relative sector offset to bitmap */
/* cached value of bdev->disk_conf->meta_dev_idx (see below) */
s32 meta_dev_idx;
/* see al_tr_number_to_on_disk_sector() */
u32 al_stripes;
u32 al_stripe_size_4k;
u32 al_size_4k; /* cached product of the above */
struct drbd_backing_dev {
struct block_device *backing_bdev;
struct block_device *md_bdev;
struct drbd_md md;
struct disk_conf *disk_conf; /* RCU, for updates: resource->conf_update */
sector_t known_size; /* last known size of that backing device */
struct drbd_md_io {
struct page *page;
unsigned long start_jif; /* last call to drbd_md_get_buffer */
unsigned long submit_jif; /* last _drbd_md_sync_page_io() submit */
const char *current_use;
atomic_t in_use;
unsigned int done;
int error;
struct bm_io_work {
struct drbd_work w;
char *why;
enum bm_flag flags;
int (*io_fn)(struct drbd_device *device);
void (*done)(struct drbd_device *device, int rv);
struct fifo_buffer {
unsigned int head_index;
unsigned int size;
int total; /* sum of all values */
int values[0];
extern struct fifo_buffer *fifo_alloc(int fifo_size);
/* flag bits per connection */
enum {
NET_CONGESTED, /* The data socket is congested */
RESOLVE_CONFLICTS, /* Set on one node, cleared on the peer! */
GOT_PING_ACK, /* set when we receive a ping_ack packet, ping_wait gets woken */
CONN_WD_ST_CHG_REQ, /* A cluster wide state change on the connection is active */
CONN_DRY_RUN, /* Expect disconnect after resync handshake. */
CREATE_BARRIER, /* next P_DATA is preceded by a P_BARRIER */
STATE_SENT, /* Do not change state/UUIDs while this is set */
CALLBACK_PENDING, /* Whether we have a call_usermodehelper(, UMH_WAIT_PROC)
* pending, from drbd worker context.
* If set, bdi_write_congested() returns true,
* so shrink_page_list() would not recurse into,
* and potentially deadlock on, this drbd worker.
DEVICE_WORK_PENDING, /* tell worker that some device has pending work */
enum which_state { NOW, OLD = NOW, NEW };
struct drbd_resource {
char *name;
struct dentry *debugfs_res;
struct dentry *debugfs_res_volumes;
struct dentry *debugfs_res_connections;
struct dentry *debugfs_res_in_flight_summary;
struct kref kref;
struct idr devices; /* volume number to device mapping */
struct list_head connections;
struct list_head resources;
struct res_opts res_opts;
struct mutex conf_update; /* mutex for ready-copy-update of net_conf and disk_conf */
struct mutex adm_mutex; /* mutex to serialize administrative requests */
spinlock_t req_lock;
unsigned susp:1; /* IO suspended by user */
unsigned susp_nod:1; /* IO suspended because no data */
unsigned susp_fen:1; /* IO suspended because fence peer handler runs */
enum write_ordering_e write_ordering;
cpumask_var_t cpu_mask;
struct drbd_thread_timing_details
unsigned long start_jif;
void *cb_addr;
const char *caller_fn;
unsigned int line;
unsigned int cb_nr;
struct drbd_connection {
struct list_head connections;
struct drbd_resource *resource;
struct dentry *debugfs_conn;
struct dentry *debugfs_conn_callback_history;
struct dentry *debugfs_conn_oldest_requests;
struct kref kref;
struct idr peer_devices; /* volume number to peer device mapping */
enum drbd_conns cstate; /* Only C_STANDALONE to C_WF_REPORT_PARAMS */
struct mutex cstate_mutex; /* Protects graceful disconnects */
unsigned int connect_cnt; /* Inc each time a connection is established */
unsigned long flags;
struct net_conf *net_conf; /* content protected by rcu */
wait_queue_head_t ping_wait; /* Woken upon reception of a ping, and a state change */
struct sockaddr_storage my_addr;
int my_addr_len;
struct sockaddr_storage peer_addr;
int peer_addr_len;
struct drbd_socket data; /* data/barrier/cstate/parameter packets */
struct drbd_socket meta; /* ping/ack (metadata) packets */
int agreed_pro_version; /* actually used protocol version */
u32 agreed_features;
unsigned long last_received; /* in jiffies, either socket */
unsigned int ko_count;
struct list_head transfer_log; /* all requests not yet fully processed */
struct crypto_shash *cram_hmac_tfm;
struct crypto_ahash *integrity_tfm; /* checksums we compute, updates protected by connection->data->mutex */
struct crypto_ahash *peer_integrity_tfm; /* checksums we verify, only accessed from receiver thread */
struct crypto_ahash *csums_tfm;
struct crypto_ahash *verify_tfm;
void *int_dig_in;
void *int_dig_vv;
/* receiver side */
struct drbd_epoch *current_epoch;
spinlock_t epoch_lock;
unsigned int epochs;
atomic_t current_tle_nr; /* transfer log epoch number */
unsigned current_tle_writes; /* writes seen within this tl epoch */
unsigned long last_reconnect_jif;
/* empty member on older kernels without blk_start_plug() */
struct blk_plug receiver_plug;
struct drbd_thread receiver;
struct drbd_thread worker;
struct drbd_thread ack_receiver;
struct workqueue_struct *ack_sender;
/* cached pointers,
* so we can look up the oldest pending requests more quickly.
* protected by resource->req_lock */
struct drbd_request *req_next; /* DRBD 9: todo.req_next */
struct drbd_request *req_ack_pending;
struct drbd_request *req_not_net_done;
/* sender side */
struct drbd_work_queue sender_work;
unsigned int w_cb_nr; /* keeps counting up */
unsigned int r_cb_nr; /* keeps counting up */
struct drbd_thread_timing_details w_timing_details[DRBD_THREAD_DETAILS_HIST];
struct drbd_thread_timing_details r_timing_details[DRBD_THREAD_DETAILS_HIST];
struct {
unsigned long last_sent_barrier_jif;
/* whether this sender thread
* has processed a single write yet. */
bool seen_any_write_yet;
/* Which barrier number to send with the next P_BARRIER */
int current_epoch_nr;
/* how many write requests have been sent
* with req->epoch == current_epoch_nr.
* If none, no P_BARRIER will be sent. */
unsigned current_epoch_writes;
} send;
static inline bool has_net_conf(struct drbd_connection *connection)
bool has_net_conf;
has_net_conf = rcu_dereference(connection->net_conf);
return has_net_conf;
void __update_timing_details(
struct drbd_thread_timing_details *tdp,
unsigned int *cb_nr,
void *cb,
const char *fn, const unsigned int line);
#define update_worker_timing_details(c, cb) \
__update_timing_details(c->w_timing_details, &c->w_cb_nr, cb, __func__ , __LINE__ )
#define update_receiver_timing_details(c, cb) \
__update_timing_details(c->r_timing_details, &c->r_cb_nr, cb, __func__ , __LINE__ )
struct submit_worker {
struct workqueue_struct *wq;
struct work_struct worker;
/* protected by ..->resource->req_lock */
struct list_head writes;
struct drbd_peer_device {
struct list_head peer_devices;
struct drbd_device *device;
struct drbd_connection *connection;
struct work_struct send_acks_work;
struct dentry *debugfs_peer_dev;
struct drbd_device {
struct drbd_resource *resource;
struct list_head peer_devices;
struct list_head pending_bitmap_io;
unsigned long flush_jif;
struct dentry *debugfs_minor;
struct dentry *debugfs_vol;
struct dentry *debugfs_vol_oldest_requests;
struct dentry *debugfs_vol_act_log_extents;
struct dentry *debugfs_vol_resync_extents;
struct dentry *debugfs_vol_data_gen_id;
struct dentry *debugfs_vol_ed_gen_id;
unsigned int vnr; /* volume number within the connection */
unsigned int minor; /* device minor number */
struct kref kref;
/* things that are stored as / read from meta data on disk */
unsigned long flags;
/* configured by drbdsetup */
struct drbd_backing_dev *ldev __protected_by(local);
sector_t p_size; /* partner's disk size */
struct request_queue *rq_queue;
struct block_device *this_bdev;
struct gendisk *vdisk;
unsigned long last_reattach_jif;
struct drbd_work resync_work;
struct drbd_work unplug_work;
struct timer_list resync_timer;
struct timer_list md_sync_timer;
struct timer_list start_resync_timer;
struct timer_list request_timer;
/* Used after attach while negotiating new disk state. */
union drbd_state new_state_tmp;
union drbd_dev_state state;
wait_queue_head_t misc_wait;
wait_queue_head_t state_wait; /* upon each state change. */
unsigned int send_cnt;
unsigned int recv_cnt;
unsigned int read_cnt;
unsigned int writ_cnt;
unsigned int al_writ_cnt;
unsigned int bm_writ_cnt;
atomic_t ap_bio_cnt; /* Requests we need to complete */
atomic_t ap_actlog_cnt; /* Requests waiting for activity log */
atomic_t ap_pending_cnt; /* AP data packets on the wire, ack expected */
atomic_t rs_pending_cnt; /* RS request/data packets on the wire */
atomic_t unacked_cnt; /* Need to send replies for */
atomic_t local_cnt; /* Waiting for local completion */
atomic_t suspend_cnt;
/* Interval tree of pending local requests */
struct rb_root read_requests;
struct rb_root write_requests;
/* for statistics and timeouts */
/* [0] read, [1] write */
struct list_head pending_master_completion[2];
struct list_head pending_completion[2];
/* use checksums for *this* resync */
bool use_csums;
/* blocks to resync in this run [unit BM_BLOCK_SIZE] */
unsigned long rs_total;
/* number of resync blocks that failed in this run */
unsigned long rs_failed;
/* Syncer's start time [unit jiffies] */
unsigned long rs_start;
/* cumulated time in PausedSyncX state [unit jiffies] */
unsigned long rs_paused;
/* skipped because csum was equal [unit BM_BLOCK_SIZE] */
unsigned long rs_same_csum;
/* block not up-to-date at mark [unit BM_BLOCK_SIZE] */
unsigned long rs_mark_left[DRBD_SYNC_MARKS];
/* marks's time [unit jiffies] */
unsigned long rs_mark_time[DRBD_SYNC_MARKS];
/* current index into rs_mark_{left,time} */
int rs_last_mark;
unsigned long rs_last_bcast; /* [unit jiffies] */
/* where does the admin want us to start? (sector) */
sector_t ov_start_sector;
sector_t ov_stop_sector;
/* where are we now? (sector) */
sector_t ov_position;
/* Start sector of out of sync range (to merge printk reporting). */
sector_t ov_last_oos_start;
/* size of out-of-sync range in sectors. */
sector_t ov_last_oos_size;
unsigned long ov_left; /* in bits */
struct drbd_bitmap *bitmap;
unsigned long bm_resync_fo; /* bit offset for drbd_bm_find_next */
/* Used to track operations of resync... */
struct lru_cache *resync;
/* Number of locked elements in resync LRU */
unsigned int resync_locked;
/* resync extent number waiting for application requests */
unsigned int resync_wenr;
int open_cnt;
u64 *p_uuid;
struct list_head active_ee; /* IO in progress (P_DATA gets written to disk) */
struct list_head sync_ee; /* IO in progress (P_RS_DATA_REPLY gets written to disk) */
struct list_head done_ee; /* need to send P_WRITE_ACK */
struct list_head read_ee; /* [RS]P_DATA_REQUEST being read */
struct list_head net_ee; /* zero-copy network send in progress */
int next_barrier_nr;
struct list_head resync_reads;
atomic_t pp_in_use; /* allocated from page pool */
atomic_t pp_in_use_by_net; /* sendpage()d, still referenced by tcp */
wait_queue_head_t ee_wait;
struct drbd_md_io md_io;
spinlock_t al_lock;
wait_queue_head_t al_wait;
struct lru_cache *act_log; /* activity log */
unsigned int al_tr_number;
int al_tr_cycle;
wait_queue_head_t seq_wait;
atomic_t packet_seq;
unsigned int peer_seq;
spinlock_t peer_seq_lock;
unsigned long comm_bm_set; /* communicated number of set bits. */
struct bm_io_work bm_io_work;
u64 ed_uuid; /* UUID of the exposed data */
struct mutex own_state_mutex;
struct mutex *state_mutex; /* either own_state_mutex or first_peer_device(device)->connection->cstate_mutex */
char congestion_reason; /* Why we where congested... */
atomic_t rs_sect_in; /* for incoming resync data rate, SyncTarget */
atomic_t rs_sect_ev; /* for submitted resync data rate, both */
int rs_last_sect_ev; /* counter to compare with */
int rs_last_events; /* counter of read or write "events" (unit sectors)
* on the lower level device when we last looked. */
int c_sync_rate; /* current resync rate after syncer throttle magic */
struct fifo_buffer *rs_plan_s; /* correction values of resync planer (RCU, connection->conn_update) */
int rs_in_flight; /* resync sectors in flight (to proxy, in proxy and from proxy) */
atomic_t ap_in_flight; /* App sectors in flight (waiting for ack) */
unsigned int peer_max_bio_size;
unsigned int local_max_bio_size;
/* any requests that would block in drbd_make_request()
* are deferred to this single-threaded work queue */
struct submit_worker submit;
struct drbd_bm_aio_ctx {
struct drbd_device *device;
struct list_head list; /* on device->pending_bitmap_io */;
unsigned long start_jif;
atomic_t in_flight;
unsigned int done;
unsigned flags;
#define BM_AIO_READ 8
int error;
struct kref kref;
struct drbd_config_context {
/* assigned from drbd_genlmsghdr */
unsigned int minor;
/* assigned from request attributes, if present */
unsigned int volume;
/* pointer into the request skb,
* limited lifetime! */
char *resource_name;
struct nlattr *my_addr;
struct nlattr *peer_addr;
/* reply buffer */
struct sk_buff *reply_skb;
/* pointer into reply buffer */
struct drbd_genlmsghdr *reply_dh;
/* resolved from attributes, if possible */
struct drbd_device *device;
struct drbd_resource *resource;
struct drbd_connection *connection;
static inline struct drbd_device *minor_to_device(unsigned int minor)
return (struct drbd_device *)idr_find(&drbd_devices, minor);
static inline struct drbd_peer_device *first_peer_device(struct drbd_device *device)
return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
static inline struct drbd_peer_device *
conn_peer_device(struct drbd_connection *connection, int volume_number)
return idr_find(&connection->peer_devices, volume_number);
#define for_each_resource(resource, _resources) \
list_for_each_entry(resource, _resources, resources)
#define for_each_resource_rcu(resource, _resources) \
list_for_each_entry_rcu(resource, _resources, resources)
#define for_each_resource_safe(resource, tmp, _resources) \
list_for_each_entry_safe(resource, tmp, _resources, resources)
#define for_each_connection(connection, resource) \
list_for_each_entry(connection, &resource->connections, connections)
#define for_each_connection_rcu(connection, resource) \
list_for_each_entry_rcu(connection, &resource->connections, connections)
#define for_each_connection_safe(connection, tmp, resource) \
list_for_each_entry_safe(connection, tmp, &resource->connections, connections)
#define for_each_peer_device(peer_device, device) \
list_for_each_entry(peer_device, &device->peer_devices, peer_devices)
#define for_each_peer_device_rcu(peer_device, device) \
list_for_each_entry_rcu(peer_device, &device->peer_devices, peer_devices)
#define for_each_peer_device_safe(peer_device, tmp, device) \
list_for_each_entry_safe(peer_device, tmp, &device->peer_devices, peer_devices)
static inline unsigned int device_to_minor(struct drbd_device *device)
return device->minor;
* function declarations
/* drbd_main.c */
enum dds_flags {
DDSF_NO_RESYNC = 2, /* Do not run a resync for the new space */
extern void drbd_init_set_defaults(struct drbd_device *device);
extern int drbd_thread_start(struct drbd_thread *thi);
extern void _drbd_thread_stop(struct drbd_thread *thi, int restart, int wait);
extern void drbd_thread_current_set_cpu(struct drbd_thread *thi);
#define drbd_thread_current_set_cpu(A) ({})
extern void tl_release(struct drbd_connection *, unsigned int barrier_nr,
unsigned int set_size);
extern void tl_clear(struct drbd_connection *);
extern void drbd_free_sock(struct drbd_connection *connection);
extern int drbd_send(struct drbd_connection *connection, struct socket *sock,
void *buf, size_t size, unsigned msg_flags);
extern int drbd_send_all(struct drbd_connection *, struct socket *, void *, size_t,
extern int __drbd_send_protocol(struct drbd_connection *connection, enum drbd_packet cmd);
extern int drbd_send_protocol(struct drbd_connection *connection);
extern int drbd_send_uuids(struct drbd_peer_device *);
extern int drbd_send_uuids_skip_initial_sync(struct drbd_peer_device *);
extern void drbd_gen_and_send_sync_uuid(struct drbd_peer_device *);
extern int drbd_send_sizes(struct drbd_peer_device *, int trigger_reply, enum dds_flags flags);
extern int drbd_send_state(struct drbd_peer_device *, union drbd_state s);
extern int drbd_send_current_state(struct drbd_peer_device *);
extern int drbd_send_sync_param(struct drbd_peer_device *);
extern void drbd_send_b_ack(struct drbd_connection *connection, u32 barrier_nr,
u32 set_size);
extern int drbd_send_ack(struct drbd_peer_device *, enum drbd_packet,
struct drbd_peer_request *);
extern void drbd_send_ack_rp(struct drbd_peer_device *, enum drbd_packet,
struct p_block_req *rp);
extern void drbd_send_ack_dp(struct drbd_peer_device *, enum drbd_packet,
struct p_data *dp, int data_size);
extern int drbd_send_ack_ex(struct drbd_peer_device *, enum drbd_packet,
sector_t sector, int blksize, u64 block_id);
extern int drbd_send_out_of_sync(struct drbd_peer_device *, struct drbd_request *);
extern int drbd_send_block(struct drbd_peer_device *, enum drbd_packet,
struct drbd_peer_request *);
extern int drbd_send_dblock(struct drbd_peer_device *, struct drbd_request *req);
extern int drbd_send_drequest(struct drbd_peer_device *, int cmd,
sector_t sector, int size, u64 block_id);
extern int drbd_send_drequest_csum(struct drbd_peer_device *, sector_t sector,
int size, void *digest, int digest_size,
enum drbd_packet cmd);
extern int drbd_send_ov_request(struct drbd_peer_device *, sector_t sector, int size);
extern int drbd_send_bitmap(struct drbd_device *device);
extern void drbd_send_sr_reply(struct drbd_peer_device *, enum drbd_state_rv retcode);
extern void conn_send_sr_reply(struct drbd_connection *connection, enum drbd_state_rv retcode);
extern int drbd_send_rs_deallocated(struct drbd_peer_device *, struct drbd_peer_request *);
extern void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev);
extern void drbd_device_cleanup(struct drbd_device *device);
extern void drbd_print_uuids(struct drbd_device *device, const char *text);
extern void drbd_queue_unplug(struct drbd_device *device);
extern void conn_md_sync(struct drbd_connection *connection);
extern void drbd_md_write(struct drbd_device *device, void *buffer);
extern void drbd_md_sync(struct drbd_device *device);
extern int drbd_md_read(struct drbd_device *device, struct drbd_backing_dev *bdev);
extern void drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
extern void _drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
extern void drbd_uuid_new_current(struct drbd_device *device) __must_hold(local);
extern void drbd_uuid_set_bm(struct drbd_device *device, u64 val) __must_hold(local);
extern void drbd_uuid_move_history(struct drbd_device *device) __must_hold(local);
extern void __drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
extern void drbd_md_set_flag(struct drbd_device *device, int flags) __must_hold(local);
extern void drbd_md_clear_flag(struct drbd_device *device, int flags)__must_hold(local);
extern int drbd_md_test_flag(struct drbd_backing_dev *, int);
extern void drbd_md_mark_dirty(struct drbd_device *device);
extern void drbd_queue_bitmap_io(struct drbd_device *device,
int (*io_fn)(struct drbd_device *),
void (*done)(struct drbd_device *, int),
char *why, enum bm_flag flags);
extern int drbd_bitmap_io(struct drbd_device *device,
int (*io_fn)(struct drbd_device *),
char *why, enum bm_flag flags);
extern int drbd_bitmap_io_from_worker(struct drbd_device *device,
int (*io_fn)(struct drbd_device *),
char *why, enum bm_flag flags);
extern int drbd_bmio_set_n_write(struct drbd_device *device) __must_hold(local);
extern int drbd_bmio_clear_n_write(struct drbd_device *device) __must_hold(local);
/* Meta data layout
* We currently have two possible layouts.
* Offsets in (512 byte) sectors.
* external:
* |----------- md_size_sect ------------------|
* [ 4k superblock ][ activity log ][ Bitmap ]
* | al_offset == 8 |
* | bm_offset = al_offset + X |
* ==> bitmap sectors = md_size_sect - bm_offset
* Variants:
* old, indexed fixed size meta data:
* internal:
* |----------- md_size_sect ------------------|
* [data.....][ Bitmap ][ activity log ][ 4k superblock ][padding*]
* | al_offset < 0 |
* | bm_offset = al_offset - Y |
* ==> bitmap sectors = Y = al_offset - bm_offset
* [padding*] are zero or up to 7 unused 512 Byte sectors to the
* end of the device, so that the [4k superblock] will be 4k aligned.
* The activity log consists of 4k transaction blocks,
* which are written in a ring-buffer, or striped ring-buffer like fashion,
* which are writtensize used to be fixed 32kB,
* but is about to become configurable.
/* Our old fixed size meta data layout
* allows up to about 3.8TB, so if you want more,
* you need to use the "flexible" meta data format. */
#define MD_128MB_SECT (128LLU << 11) /* 128 MB, unit sectors */
#define MD_4kB_SECT 8
#define MD_32kB_SECT 64
/* One activity log extent represents 4M of storage */
#define AL_EXTENT_SHIFT 22
/* We could make these currently hardcoded constants configurable
* variables at create-md time (or even re-configurable at runtime?).
* Which will require some more changes to the DRBD "super block"
* and attach code.
* updates per transaction:
* This many changes to the active set can be logged with one transaction.
* This number is arbitrary.
* context per transaction:
* This many context extent numbers are logged with each transaction.
* This number is resulting from the transaction block size (4k), the layout
* of the transaction header, and the number of updates per transaction.
* See drbd_actlog.c:struct al_transaction_on_disk
* */
#define AL_UPDATES_PER_TRANSACTION 64 // arbitrary
#define AL_CONTEXT_PER_TRANSACTION 919 // (4096 - 36 - 6*64)/4
#if BITS_PER_LONG == 32
#define LN2_BPL 5
#define cpu_to_lel(A) cpu_to_le32(A)
#define lel_to_cpu(A) le32_to_cpu(A)
#elif BITS_PER_LONG == 64
#define LN2_BPL 6
#define cpu_to_lel(A) cpu_to_le64(A)
#define lel_to_cpu(A) le64_to_cpu(A)
#error "LN2 of BITS_PER_LONG unknown!"
/* resync bitmap */
/* 16MB sized 'bitmap extent' to track syncer usage */
struct bm_extent {
int rs_left; /* number of bits set (out of sync) in this extent. */
int rs_failed; /* number of failed resync requests in this extent. */
unsigned long flags;
struct lc_element lce;
#define BME_NO_WRITES 0 /* bm_extent.flags: no more requests on this one! */
#define BME_LOCKED 1 /* bm_extent.flags: syncer active on this one. */
#define BME_PRIORITY 2 /* finish resync IO on this extent ASAP! App IO waiting! */
/* drbd_bitmap.c */
* We need to store one bit for a block.
* Example: 1GB disk @ 4096 byte blocks ==> we need 32 KB bitmap.
* Bit 0 ==> local node thinks this block is binary identical on both nodes
* Bit 1 ==> local node thinks this block needs to be synced.
#define SLEEP_TIME (HZ/10)
/* We do bitmap IO in units of 4k blocks.
* We also still have a hardcoded 4k per bit relation. */
#define BM_BLOCK_SHIFT 12 /* 4k per bit */
/* mostly arbitrarily set the represented size of one bitmap extent,
* aka resync extent, to 16 MiB (which is also 512 Byte worth of bitmap
* at 4k per bit resolution) */
#define BM_EXT_SHIFT 24 /* 16 MiB per resync extent */
#if (BM_EXT_SHIFT != 24) || (BM_BLOCK_SHIFT != 12)
#error "HAVE YOU FIXED drbdmeta AS WELL??"
/* thus many _storage_ sectors are described by one bit */
#define BM_SECT_TO_BIT(x) ((x)>>(BM_BLOCK_SHIFT-9))
#define BM_BIT_TO_SECT(x) ((sector_t)(x)<<(BM_BLOCK_SHIFT-9))
/* bit to represented kilo byte conversion */
#define Bit2KB(bits) ((bits)<<(BM_BLOCK_SHIFT-10))
/* in which _bitmap_ extent (resp. sector) the bit for a certain
* _storage_ sector is located in */
#define BM_SECT_TO_EXT(x) ((x)>>(BM_EXT_SHIFT-9))
#define BM_BIT_TO_EXT(x) ((x) >> (BM_EXT_SHIFT - BM_BLOCK_SHIFT))
/* first storage sector a bitmap extent corresponds to */
#define BM_EXT_TO_SECT(x) ((sector_t)(x) << (BM_EXT_SHIFT-9))
/* how much _storage_ sectors we have per bitmap extent */
/* how many bits are covered by one bitmap extent (resync extent) */
/* in one sector of the bitmap, we have this many activity_log extents. */
/* the extent in "PER_EXTENT" below is an activity log extent
* we need that many (long words/bytes) to store the bitmap
* of one AL_EXTENT_SIZE chunk of storage.
* we can store the bitmap for that many AL_EXTENTS within
* one sector of the _on_disk_ bitmap:
* bit 0 bit 37 bit 38 bit (512*8)-1
* ...|........|........|.. // ..|........|
* sect. 0 `296 `304 ^(512*8*8)-1
#define BM_BYTES_PER_EXT ( (AL_EXT_SIZE/BM_BLOCK_SIZE) / 8 ) // 128
#define BM_EXT_PER_SECT ( 512 / BM_BYTES_PER_EXTENT ) // 4
#define DRBD_MAX_SECTORS_32 (0xffffffffLU)
/* we have a certain meta data variant that has a fixed on-disk size of 128
* MiB, of which 4k are our "superblock", and 32k are the fixed size activity
* log, leaving this many sectors for the bitmap.
((MD_128MB_SECT - MD_32kB_SECT - MD_4kB_SECT) * (1LL<<(BM_EXT_SHIFT-9)))
#if !defined(CONFIG_LBDAF) && BITS_PER_LONG == 32
/* 16 TB in units of sectors */
#if BITS_PER_LONG == 32
/* adjust by one page worth of bitmap,
* so we won't wrap around in drbd_bm_find_next_bit.
* you should use 64bit OS for that much storage, anyways. */
/* we allow up to 1 PiB now on 64bit architecture with "flexible" meta data */
#define DRBD_MAX_SECTORS_FLEX (1UL << 51)
/* corresponds to (1UL << 38) bits right now. */
/* Estimate max bio size as 256 * PAGE_SIZE,
* so for typical PAGE_SIZE of 4k, that is (1<<20) Byte.
* Since we may live in a mixed-platform cluster,
* we limit us to a platform agnostic constant here for now.
* A followup commit may allow even bigger BIO sizes,
* once we thought that through. */
#define DRBD_MAX_BIO_SIZE (1U << 20)
#error Architecture not supported: DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
#define DRBD_MAX_BIO_SIZE_SAFE (1U << 12) /* Works always = 4k */
#define DRBD_MAX_SIZE_H80_PACKET (1U << 15) /* Header 80 only allows packets up to 32KiB data */
#define DRBD_MAX_BIO_SIZE_P95 (1U << 17) /* Protocol 95 to 99 allows bios up to 128KiB */
/* For now, don't allow more than half of what we can "activate" in one
* activity log transaction to be discarded in one go. We may need to rework
* drbd_al_begin_io() to allow for even larger discard ranges */
extern int drbd_bm_init(struct drbd_device *device);
extern int drbd_bm_resize(struct drbd_device *device, sector_t sectors, int set_new_bits);
extern void drbd_bm_cleanup(struct drbd_device *device);
extern void drbd_bm_set_all(struct drbd_device *device);
extern void drbd_bm_clear_all(struct drbd_device *device);
/* set/clear/test only a few bits at a time */
extern int drbd_bm_set_bits(
struct drbd_device *device, unsigned long s, unsigned long e);
extern int drbd_bm_clear_bits(
struct drbd_device *device, unsigned long s, unsigned long e);
extern int drbd_bm_count_bits(
struct drbd_device *device, const unsigned long s, const unsigned long e);
/* bm_set_bits variant for use while holding drbd_bm_lock,
* may process the whole bitmap in one go */
extern void _drbd_bm_set_bits(struct drbd_device *device,
const unsigned long s, const unsigned long e);
extern int drbd_bm_test_bit(struct drbd_device *device, unsigned long bitnr);
extern int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr);
extern int drbd_bm_read(struct drbd_device *device) __must_hold(local);
extern void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr);
extern int drbd_bm_write(struct drbd_device *device) __must_hold(local);
extern void drbd_bm_reset_al_hints(struct drbd_device *device) __must_hold(local);
extern int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local);
extern int drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local);
extern int drbd_bm_write_all(struct drbd_device *device) __must_hold(local);
extern int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local);
extern size_t drbd_bm_words(struct drbd_device *device);
extern unsigned long drbd_bm_bits(struct drbd_device *device);
extern sector_t drbd_bm_capacity(struct drbd_device *device);
#define DRBD_END_OF_BITMAP (~(unsigned long)0)
extern unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo);
/* bm_find_next variants for use while you hold drbd_bm_lock() */
extern unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo);
extern unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo);
extern unsigned long _drbd_bm_total_weight(struct drbd_device *device);
extern unsigned long drbd_bm_total_weight(struct drbd_device *device);
/* for receive_bitmap */
extern void drbd_bm_merge_lel(struct drbd_device *device, size_t offset,
size_t number, unsigned long *buffer);
/* for _drbd_send_bitmap */
extern void drbd_bm_get_lel(struct drbd_device *device, size_t offset,
size_t number, unsigned long *buffer);
extern void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags);
extern void drbd_bm_unlock(struct drbd_device *device);
/* drbd_main.c */
extern struct kmem_cache *drbd_request_cache;
extern struct kmem_cache *drbd_ee_cache; /* peer requests */
extern struct kmem_cache *drbd_bm_ext_cache; /* bitmap extents */
extern struct kmem_cache *drbd_al_ext_cache; /* activity log extents */
extern mempool_t *drbd_request_mempool;
extern mempool_t *drbd_ee_mempool;
/* drbd's page pool, used to buffer data received from the peer,
* or data requested by the peer.
* This does not have an emergency reserve.
* When allocating from this pool, it first takes pages from the pool.
* Only if the pool is depleted will try to allocate from the system.
* The assumption is that pages taken from this pool will be processed,
* and given back, "quickly", and then can be recycled, so we can avoid
* frequent calls to alloc_page(), and still will be able to make progress even
* under memory pressure.
extern struct page *drbd_pp_pool;
extern spinlock_t drbd_pp_lock;
extern int drbd_pp_vacant;
extern wait_queue_head_t drbd_pp_wait;
/* We also need a standard (emergency-reserve backed) page pool
* for meta data IO (activity log, bitmap).
* We can keep it global, as long as it is used as "N pages at a time".
* 128 should be plenty, currently we probably can get away with as few as 1.
extern mempool_t *drbd_md_io_page_pool;
/* We also need to make sure we get a bio
* when we need it for housekeeping purposes */
extern struct bio_set *drbd_md_io_bio_set;
/* to allocate from that set */
extern struct bio *bio_alloc_drbd(gfp_t gfp_mask);
/* And a bio_set for cloning */
extern struct bio_set *drbd_io_bio_set;
extern struct mutex resources_mutex;
extern int conn_lowest_minor(struct drbd_connection *connection);
extern enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor);
extern void drbd_destroy_device(struct kref *kref);
extern void drbd_delete_device(struct drbd_device *device);
extern struct drbd_resource *drbd_create_resource(const char *name);
extern void drbd_free_resource(struct drbd_resource *resource);
extern int set_resource_options(struct drbd_resource *resource, struct res_opts *res_opts);
extern struct drbd_connection *conn_create(const char *name, struct res_opts *res_opts);
extern void drbd_destroy_connection(struct kref *kref);
extern struct drbd_connection *conn_get_by_addrs(void *my_addr, int my_addr_len,
void *peer_addr, int peer_addr_len);
extern struct drbd_resource *drbd_find_resource(const char *name);
extern void drbd_destroy_resource(struct kref *kref);
extern void conn_free_crypto(struct drbd_connection *connection);
/* drbd_req */
extern void do_submit(struct work_struct *ws);
extern void __drbd_make_request(struct drbd_device *, struct bio *, unsigned long);
extern blk_qc_t drbd_make_request(struct request_queue *q, struct bio *bio);
extern int drbd_read_remote(struct drbd_device *device, struct drbd_request *req);
extern int is_valid_ar_handle(struct drbd_request *, sector_t);
/* drbd_nl.c */
extern struct mutex notification_mutex;
extern void drbd_suspend_io(struct drbd_device *device);
extern void drbd_resume_io(struct drbd_device *device);
extern char *ppsize(char *buf, unsigned long long size);
extern sector_t drbd_new_dev_size(struct drbd_device *, struct drbd_backing_dev *, sector_t, int);
enum determine_dev_size {
DS_ERROR = -1,
DS_GREW = 2,
extern enum determine_dev_size
drbd_determine_dev_size(struct drbd_device *, enum dds_flags, struct resize_parms *) __must_hold(local);
extern void resync_after_online_grow(struct drbd_device *);
extern void drbd_reconsider_queue_parameters(struct drbd_device *device,
struct drbd_backing_dev *bdev, struct o_qlim *o);
extern enum drbd_state_rv drbd_set_role(struct drbd_device *device,
enum drbd_role new_role,
int force);
extern bool conn_try_outdate_peer(struct drbd_connection *connection);
extern void conn_try_outdate_peer_async(struct drbd_connection *connection);
extern enum drbd_peer_state conn_khelper(struct drbd_connection *connection, char *cmd);
extern int drbd_khelper(struct drbd_device *device, char *cmd);
/* drbd_worker.c */
/* bi_end_io handlers */
extern void drbd_md_endio(struct bio *bio);
extern void drbd_peer_request_endio(struct bio *bio);
extern void drbd_request_endio(struct bio *bio);
extern int drbd_worker(struct drbd_thread *thi);
enum drbd_ret_code drbd_resync_after_valid(struct drbd_device *device, int o_minor);
void drbd_resync_after_changed(struct drbd_device *device);
extern void drbd_start_resync(struct drbd_device *device, enum drbd_conns side);
extern void resume_next_sg(struct drbd_device *device);
extern void suspend_other_sg(struct drbd_device *device);
extern int drbd_resync_finished(struct drbd_device *device);
/* maybe rather drbd_main.c ? */
extern void *drbd_md_get_buffer(struct drbd_device *device, const char *intent);
extern void drbd_md_put_buffer(struct drbd_device *device);
extern int drbd_md_sync_page_io(struct drbd_device *device,
struct drbd_backing_dev *bdev, sector_t sector, int op);
extern void drbd_ov_out_of_sync_found(struct drbd_device *, sector_t, int);
extern void wait_until_done_or_force_detached(struct drbd_device *device,
struct drbd_backing_dev *bdev, unsigned int *done);
extern void drbd_rs_controller_reset(struct drbd_device *device);
static inline void ov_out_of_sync_print(struct drbd_device *device)
if (device->ov_last_oos_size) {
drbd_err(device, "Out of sync: start=%llu, size=%lu (sectors)\n",
(unsigned long long)device->ov_last_oos_start,
(unsigned long)device->ov_last_oos_size);
device->ov_last_oos_size = 0;
extern void drbd_csum_bio(struct crypto_ahash *, struct bio *, void *);
extern void drbd_csum_ee(struct crypto_ahash *, struct drbd_peer_request *, void *);
/* worker callbacks */
extern int w_e_end_data_req(struct drbd_work *, int);
extern int w_e_end_rsdata_req(struct drbd_work *, int);
extern int w_e_end_csum_rs_req(struct drbd_work *, int);
extern int w_e_end_ov_reply(struct drbd_work *, int);
extern int w_e_end_ov_req(struct drbd_work *, int);
extern int w_ov_finished(struct drbd_work *, int);
extern int w_resync_timer(struct drbd_work *, int);
extern int w_send_write_hint(struct drbd_work *, int);
extern int w_send_dblock(struct drbd_work *, int);
extern int w_send_read_req(struct drbd_work *, int);
extern int w_e_reissue(struct drbd_work *, int);
extern int w_restart_disk_io(struct drbd_work *, int);
extern int w_send_out_of_sync(struct drbd_work *, int);
extern int w_start_resync(struct drbd_work *, int);
extern void resync_timer_fn(unsigned long data);
extern void start_resync_timer_fn(unsigned long data);
extern void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req);
/* drbd_receiver.c */
extern int drbd_receiver(struct drbd_thread *thi);
extern int drbd_ack_receiver(struct drbd_thread *thi);
extern void drbd_send_ping_wf(struct work_struct *ws);
extern void drbd_send_acks_wf(struct work_struct *ws);
extern bool drbd_rs_c_min_rate_throttle(struct drbd_device *device);
extern bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
bool throttle_if_app_is_waiting);
extern int drbd_submit_peer_request(struct drbd_device *,
struct drbd_peer_request *, const unsigned,
const unsigned, const int);
extern int drbd_free_peer_reqs(struct drbd_device *, struct list_head *);
extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *, u64,
sector_t, unsigned int,
unsigned int,
gfp_t) __must_hold(local);
extern void __drbd_free_peer_req(struct drbd_device *, struct drbd_peer_request *,
#define drbd_free_peer_req(m,e) __drbd_free_peer_req(m, e, 0)
#define drbd_free_net_peer_req(m,e) __drbd_free_peer_req(m, e, 1)
extern struct page *drbd_alloc_pages(struct drbd_peer_device *, unsigned int, bool);
extern void drbd_set_recv_tcq(struct drbd_device *device, int tcq_enabled);
extern void _drbd_clear_done_ee(struct drbd_device *device, struct list_head *to_be_freed);
extern int drbd_connected(struct drbd_peer_device *);
static inline void drbd_tcp_cork(struct socket *sock)
int val = 1;
(void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
(char*)&val, sizeof(val));
static inline void drbd_tcp_uncork(struct socket *sock)
int val = 0;
(void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
(char*)&val, sizeof(val));
static inline void drbd_tcp_nodelay(struct socket *sock)
int val = 1;
(void) kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
(char*)&val, sizeof(val));
static inline void drbd_tcp_quickack(struct socket *sock)
int val = 2;
(void) kernel_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
(char*)&val, sizeof(val));
/* sets the number of 512 byte sectors of our virtual device */
static inline void drbd_set_my_capacity(struct drbd_device *device,
sector_t size)
/* set_capacity(device->this_bdev->bd_disk, size); */
set_capacity(device->vdisk, size);
device->this_bdev->bd_inode->i_size = (loff_t)size << 9;
* used to submit our private bio
static inline void drbd_generic_make_request(struct drbd_device *device,
int fault_type, struct bio *bio)
if (!bio->bi_disk) {
drbd_err(device, "drbd_generic_make_request: bio->bi_disk == NULL\n");
bio->bi_status = BLK_STS_IOERR;
if (drbd_insert_fault(device, fault_type))
void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backing_dev *bdev,
enum write_ordering_e wo);
/* drbd_proc.c */
extern struct proc_dir_entry *drbd_proc;
extern const struct file_operations drbd_proc_fops;
/* drbd_actlog.c */
extern bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i);
extern int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i);
extern void drbd_al_begin_io_commit(struct drbd_device *device);
extern bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i);
extern void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i);
extern void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i);
extern void drbd_rs_complete_io(struct drbd_device *device, sector_t sector);
extern int drbd_rs_begin_io(struct drbd_device *device, sector_t sector);
extern int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector);
extern void drbd_rs_cancel_all(struct drbd_device *device);
extern int drbd_rs_del_all(struct drbd_device *device);
extern void drbd_rs_failed_io(struct drbd_device *device,
sector_t sector, int size);
extern void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go);
enum update_sync_bits_mode { RECORD_RS_FAILED, SET_OUT_OF_SYNC, SET_IN_SYNC };
extern int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
enum update_sync_bits_mode mode);
#define drbd_set_in_sync(device, sector, size) \
__drbd_change_sync(device, sector, size, SET_IN_SYNC)
#define drbd_set_out_of_sync(device, sector, size) \
__drbd_change_sync(device, sector, size, SET_OUT_OF_SYNC)
#define drbd_rs_failed_io(device, sector, size) \
__drbd_change_sync(device, sector, size, RECORD_RS_FAILED)
extern void drbd_al_shrink(struct drbd_device *device);
extern int drbd_al_initialize(struct drbd_device *, void *);
/* drbd_nl.c */
/* state info broadcast */
struct sib_info {
enum drbd_state_info_bcast_reason sib_reason;
union {
struct {
char *helper_name;
unsigned helper_exit_code;
struct {
union drbd_state os;
union drbd_state ns;
void drbd_bcast_event(struct drbd_device *device, const struct sib_info *sib);
extern void notify_resource_state(struct sk_buff *,
unsigned int,
struct drbd_resource *,
struct resource_info *,
enum drbd_notification_type);
extern void notify_device_state(struct sk_buff *,
unsigned int,
struct drbd_device *,
struct device_info *,
enum drbd_notification_type);
extern void notify_connection_state(struct sk_buff *,
unsigned int,
struct drbd_connection *,
struct connection_info *,
enum drbd_notification_type);
extern void notify_peer_device_state(struct sk_buff *,
unsigned int,
struct drbd_peer_device *,
struct peer_device_info *,
enum drbd_notification_type);
extern void notify_helper(enum drbd_notification_type, struct drbd_device *,
struct drbd_connection *, const char *, int);
* inline helper functions
/* see also page_chain_add and friends in drbd_receiver.c */
static inline struct page *page_chain_next(struct page *page)
return (struct page *)page_private(page);
#define page_chain_for_each(page) \
for (; page && ({ prefetch(page_chain_next(page)); 1; }); \
page = page_chain_next(page))
#define page_chain_for_each_safe(page, n) \
for (; page && ({ n = page_chain_next(page); 1; }); page = n)
static inline int drbd_peer_req_has_active_page(struct drbd_peer_request *peer_req)
struct page *page = peer_req->pages;
page_chain_for_each(page) {
if (page_count(page) > 1)
return 1;
return 0;
static inline union drbd_state drbd_read_state(struct drbd_device *device)
struct drbd_resource *resource = device->resource;
union drbd_state rv;
rv.i = device->state.i;
rv.susp = resource->susp;
rv.susp_nod = resource->susp_nod;
rv.susp_fen = resource->susp_fen;
return rv;
enum drbd_force_detach_flags {
#define __drbd_chk_io_error(m,f) __drbd_chk_io_error_(m,f, __func__)
static inline void __drbd_chk_io_error_(struct drbd_device *device,
enum drbd_force_detach_flags df,
const char *where)
enum drbd_io_error_p ep;
ep = rcu_dereference(device->ldev->disk_conf)->on_io_error;
switch (ep) {
case EP_PASS_ON: /* FIXME would this be better named "Ignore"? */
if (df == DRBD_READ_ERROR || df == DRBD_WRITE_ERROR) {
if (__ratelimit(&drbd_ratelimit_state))
drbd_err(device, "Local IO failed in %s.\n", where);
if (device->state.disk > D_INCONSISTENT)
_drbd_set_state(_NS(device, disk, D_INCONSISTENT), CS_HARD, NULL);
/* Remember whether we saw a READ or WRITE error.
* Recovery of the affected area for WRITE failure is covered
* by the activity log.
* READ errors may fall outside that area though. Certain READ
* errors can be "healed" by writing good data to the affected
* blocks, which triggers block re-allocation in lower layers.
* If we can not write the bitmap after a READ error,
* we may need to trigger a full sync (see w_go_diskless()).
* Force-detach is not really an IO error, but rather a
* desperate measure to try to deal with a completely
* unresponsive lower level IO stack.
* Still it should be treated as a WRITE error.
* Meta IO error is always WRITE error:
* we read meta data only once during attach,
* which will fail in case of errors.
set_bit(WAS_IO_ERROR, &device->flags);
if (df == DRBD_READ_ERROR)
set_bit(WAS_READ_ERROR, &device->flags);
set_bit(FORCE_DETACH, &device->flags);
if (device->state.disk > D_FAILED) {
_drbd_set_state(_NS(device, disk, D_FAILED), CS_HARD, NULL);
"Local IO failed in %s. Detaching...\n", where);
* drbd_chk_io_error: Handle the on_io_error setting, should be called from all io completion handlers
* @device: DRBD device.
* @error: Error code passed to the IO completion callback
* @forcedetach: Force detach. I.e. the error happened while accessing the meta data
* See also drbd_main.c:after_state_ch() if (os.disk > D_FAILED && ns.disk == D_FAILED)
#define drbd_chk_io_error(m,e,f) drbd_chk_io_error_(m,e,f, __func__)
static inline void drbd_chk_io_error_(struct drbd_device *device,
int error, enum drbd_force_detach_flags forcedetach, const char *where)
if (error) {
unsigned long flags;
spin_lock_irqsave(&device->resource->req_lock, flags);
__drbd_chk_io_error_(device, forcedetach, where);
spin_unlock_irqrestore(&device->resource->req_lock, flags);
* drbd_md_first_sector() - Returns the first sector number of the meta data area
* @bdev: Meta data block device.
* BTW, for internal meta data, this happens to be the maximum capacity
* we could agree upon with our peer node.
static inline sector_t drbd_md_first_sector(struct drbd_backing_dev *bdev)
switch (bdev->md.meta_dev_idx) {
return bdev->md.md_offset + bdev->md.bm_offset;
return bdev->md.md_offset;
* drbd_md_last_sector() - Return the last sector number of the meta data area
* @bdev: Meta data block device.
static inline sector_t drbd_md_last_sector(struct drbd_backing_dev *bdev)
switch (bdev->md.meta_dev_idx) {
return bdev->md.md_offset + MD_4kB_SECT -1;
return bdev->md.md_offset + bdev->md.md_size_sect -1;
/* Returns the number of 512 byte sectors of the device */
static inline sector_t drbd_get_capacity(struct block_device *bdev)
/* return bdev ? get_capacity(bdev->bd_disk) : 0; */
return bdev ? i_size_read(bdev->bd_inode) >> 9 : 0;
* drbd_get_max_capacity() - Returns the capacity we announce to out peer
* @bdev: Meta data block device.
* returns the capacity we announce to out peer. we clip ourselves at the
* various MAX_SECTORS, because if we don't, current implementation will
* oops sooner or later
static inline sector_t drbd_get_max_capacity(struct drbd_backing_dev *bdev)
sector_t s;
switch (bdev->md.meta_dev_idx) {
s = drbd_get_capacity(bdev->backing_bdev)
? min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
: 0;
s = min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
/* clip at maximum size the meta device can support */
s = min_t(sector_t, s,
- bdev->md.bm_offset));
s = min_t(sector_t, DRBD_MAX_SECTORS,
return s;
* drbd_md_ss() - Return the sector number of our meta data super block
* @bdev: Meta data block device.
static inline sector_t drbd_md_ss(struct drbd_backing_dev *bdev)
const int meta_dev_idx = bdev->md.meta_dev_idx;
if (meta_dev_idx == DRBD_MD_INDEX_FLEX_EXT)
return 0;
/* Since drbd08, internal meta data is always "flexible".
* position: last 4k aligned block of 4k size */
if (meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)
return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL) - 8;
/* external, some index; this is the old fixed size layout */
return MD_128MB_SECT * bdev->md.meta_dev_idx;
static inline void
drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w)
unsigned long flags;
spin_lock_irqsave(&q->q_lock, flags);
list_add_tail(&w->list, &q->q);
spin_unlock_irqrestore(&q->q_lock, flags);
static inline void
drbd_queue_work_if_unqueued(struct drbd_work_queue *q, struct drbd_work *w)
unsigned long flags;
spin_lock_irqsave(&q->q_lock, flags);
if (list_empty_careful(&w->list))
list_add_tail(&w->list, &q->q);
spin_unlock_irqrestore(&q->q_lock, flags);
static inline void
drbd_device_post_work(struct drbd_device *device, int work_bit)
if (!test_and_set_bit(work_bit, &device->flags)) {
struct drbd_connection *connection =
struct drbd_work_queue *q = &connection->sender_work;
if (!test_and_set_bit(DEVICE_WORK_PENDING, &connection->flags))
extern void drbd_flush_workqueue(struct drbd_work_queue *work_queue);
/* To get the ack_receiver out of the blocking network stack,
* so it can change its sk_rcvtimeo from idle- to ping-timeout,
* and send a ping, we need to send a signal.
* Which signal we send is irrelevant. */
static inline void wake_ack_receiver(struct drbd_connection *connection)
struct task_struct *task = connection->ack_receiver.task;
if (task && get_t_state(&connection->ack_receiver) == RUNNING)
force_sig(SIGXCPU, task);
static inline void request_ping(struct drbd_connection *connection)
set_bit(SEND_PING, &connection->flags);
extern void *conn_prepare_command(struct drbd_connection *, struct drbd_socket *);
extern void *drbd_prepare_command(struct drbd_peer_device *, struct drbd_socket *);
extern int conn_send_command(struct drbd_connection *, struct drbd_socket *,
enum drbd_packet, unsigned int, void *,
unsigned int);
extern int drbd_send_command(struct drbd_peer_device *, struct drbd_socket *,
enum drbd_packet, unsigned int, void *,
unsigned int);
extern int drbd_send_ping(struct drbd_connection *connection);
extern int drbd_send_ping_ack(struct drbd_connection *connection);
extern int drbd_send_state_req(struct drbd_peer_device *, union drbd_state, union drbd_state);
extern int conn_send_state_req(struct drbd_connection *, union drbd_state, union drbd_state);
static inline void drbd_thread_stop(struct drbd_thread *thi)
_drbd_thread_stop(thi, false, true);
static inline void drbd_thread_stop_nowait(struct drbd_thread *thi)
_drbd_thread_stop(thi, false, false);
static inline void drbd_thread_restart_nowait(struct drbd_thread *thi)
_drbd_thread_stop(thi, true, false);
/* counts how many answer packets packets we expect from our peer,
* for either explicit application requests,
* or implicit barrier packets as necessary.
* increased:
* w_send_barrier
* it is much easier and equally valid to count what we queue for the
* worker, even before it actually was queued or send.
* (drbd_make_request_common; recovery path on read io-error)
* decreased:
* got_BarrierAck (respective tl_clear, tl_clear_barrier)
* _req_mod(req, DATA_RECEIVED)
* [from receive_DataReply]
* [from got_BlockAck (P_WRITE_ACK, P_RECV_ACK)]
* for some reason it is NOT decreased in got_NegAck,
* but in the resulting cleanup code from report_params.
* we should try to remember the reason for that...
* _req_mod(req, SEND_FAILED or SEND_CANCELED)
* [from tl_clear_barrier]
static inline void inc_ap_pending(struct drbd_device *device)
#define ERR_IF_CNT_IS_NEGATIVE(which, func, line) \
if (atomic_read(&device->which) < 0) \
drbd_err(device, "in %s:%d: " #which " = %d < 0 !\n", \
func, line, \
#define dec_ap_pending(device) _dec_ap_pending(device, __func__, __LINE__)
static inline void _dec_ap_pending(struct drbd_device *device, const char *func, int line)
if (atomic_dec_and_test(&device->ap_pending_cnt))
ERR_IF_CNT_IS_NEGATIVE(ap_pending_cnt, func, line);
/* counts how many resync-related answers we still expect from the peer
* increase decrease
* (or P_NEG_ACK with ID_SYNCER)
static inline void inc_rs_pending(struct drbd_device *device)
#define dec_rs_pending(device) _dec_rs_pending(device, __func__, __LINE__)
static inline void _dec_rs_pending(struct drbd_device *device, const char *func, int line)
ERR_IF_CNT_IS_NEGATIVE(rs_pending_cnt, func, line);
/* counts how many answers we still need to send to the peer.
* increased on
* receive_Data unless protocol A;
* we need to send a P_RECV_ACK (proto B)
* or P_WRITE_ACK (proto C)
* receive_RSDataReply (recv_resync_read) we need to send a P_WRITE_ACK
* receive_DataRequest (receive_RSDataRequest) we need to send back P_DATA
* receive_Barrier_* we need to send a P_BARRIER_ACK
static inline void inc_unacked(struct drbd_device *device)
#define dec_unacked(device) _dec_unacked(device, __func__, __LINE__)
static inline void _dec_unacked(struct drbd_device *device, const char *func, int line)
ERR_IF_CNT_IS_NEGATIVE(unacked_cnt, func, line);
#define sub_unacked(device, n) _sub_unacked(device, n, __func__, __LINE__)
static inline void _sub_unacked(struct drbd_device *device, int n, const char *func, int line)
atomic_sub(n, &device->unacked_cnt);
ERR_IF_CNT_IS_NEGATIVE(unacked_cnt, func, line);
static inline bool is_sync_target_state(enum drbd_conns connection_state)
return connection_state == C_SYNC_TARGET ||
connection_state == C_PAUSED_SYNC_T;
static inline bool is_sync_source_state(enum drbd_conns connection_state)
return connection_state == C_SYNC_SOURCE ||
connection_state == C_PAUSED_SYNC_S;
static inline bool is_sync_state(enum drbd_conns connection_state)
return is_sync_source_state(connection_state) ||
* get_ldev() - Increase the ref count on device->ldev. Returns 0 if there is no ldev
* @_device: DRBD device.
* @_min_state: Minimum device state required for success.
* You have to call put_ldev() when finished working with device->ldev.
#define get_ldev_if_state(_device, _min_state) \
(_get_ldev_if_state((_device), (_min_state)) ? \
({ __acquire(x); true; }) : false)
#define get_ldev(_device) get_ldev_if_state(_device, D_INCONSISTENT)
static inline void put_ldev(struct drbd_device *device)
enum drbd_disk_state disk_state = device->state.disk;
/* We must check the state *before* the atomic_dec becomes visible,
* or we have a theoretical race where someone hitting zero,
* while state still D_FAILED, will then see D_DISKLESS in the
* condition below and calling into destroy, where he must not, yet. */
int i = atomic_dec_return(&device->local_cnt);
/* This may be called from some endio handler,
* so we must not sleep here. */
D_ASSERT(device, i >= 0);
if (i == 0) {
if (disk_state == D_DISKLESS)
/* even internal references gone, safe to destroy */
drbd_device_post_work(device, DESTROY_DISK);
if (disk_state == D_FAILED)
/* all application IO references gone. */
if (!test_and_set_bit(GOING_DISKLESS, &device->flags))
drbd_device_post_work(device, GO_DISKLESS);
#ifndef __CHECKER__
static inline int _get_ldev_if_state(struct drbd_device *device, enum drbd_disk_state mins)
int io_allowed;
/* never get a reference while D_DISKLESS */
if (device->state.disk == D_DISKLESS)
return 0;
io_allowed = (device->state.disk >= mins);
if (!io_allowed)
return io_allowed;
extern int _get_ldev_if_state(struct drbd_device *device, enum drbd_disk_state mins);
/* this throttles on-the-fly application requests
* according to max_buffers settings;
* maybe re-implement using semaphores? */
static inline int drbd_get_max_buffers(struct drbd_device *device)
struct net_conf *nc;
int mxb;
nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
mxb = nc ? nc->max_buffers : 1000000; /* arbitrary limit on open requests */
return mxb;
static inline int drbd_state_is_stable(struct drbd_device *device)
union drbd_dev_state s = device->state;
/* DO NOT add a default clause, we want the compiler to warn us
* for any newly introduced state we may have forgotten to add here */
switch ((enum drbd_conns)s.conn) {
/* new io only accepted when there is no connection, ... */
/* ... or there is a well established connection. */
case C_VERIFY_S:
case C_VERIFY_T:
case C_AHEAD:
case C_BEHIND:
/* transitional states, IO allowed */
/* Allow IO in BM exchange states with new protocols */
if (first_peer_device(device)->connection->agreed_pro_version < 96)
return 0;
/* no new io accepted in these states */
case C_MASK:
/* not "stable" */
return 0;
switch ((enum drbd_disk_state)s.disk) {
case D_UP_TO_DATE:
case D_FAILED:
/* disk state is stable as well. */
/* no new io accepted during transitional states */
case D_MASK:
/* not "stable" */
return 0;
return 1;
static inline int drbd_suspended(struct drbd_device *device)
struct drbd_resource *resource = device->resource;
return resource->susp || resource->susp_fen || resource->susp_nod;
static inline bool may_inc_ap_bio(struct drbd_device *device)
int mxb = drbd_get_max_buffers(device);
if (drbd_suspended(device))
return false;
if (atomic_read(&device->suspend_cnt))
return false;
/* to avoid potential deadlock or bitmap corruption,
* in various places, we only allow new application io
* to start during "stable" states. */
/* no new io accepted when attaching or detaching the disk */
if (!drbd_state_is_stable(device))
return false;
/* since some older kernels don't have atomic_add_unless,
* and we are within the spinlock anyways, we have this workaround. */
if (atomic_read(&device->ap_bio_cnt) > mxb)
return false;
if (test_bit(BITMAP_IO, &device->flags))
return false;
return true;
static inline bool inc_ap_bio_cond(struct drbd_device *device)
bool rv = false;
rv = may_inc_ap_bio(device);
if (rv)
return rv;
static inline void inc_ap_bio(struct drbd_device *device)
/* we wait here
* as long as the device is suspended
* until the bitmap is no longer on the fly during connection
* handshake as long as we would exceed the max_buffer limit.
* to avoid races with the reconnect code,
* we need to atomic_inc within the spinlock. */
wait_event(device->misc_wait, inc_ap_bio_cond(device));
static inline void dec_ap_bio(struct drbd_device *device)
int mxb = drbd_get_max_buffers(device);
int ap_bio = atomic_dec_return(&device->ap_bio_cnt);
D_ASSERT(device, ap_bio >= 0);
if (ap_bio == 0 && test_bit(BITMAP_IO, &device->flags)) {
if (!test_and_set_bit(BITMAP_IO_QUEUED, &device->flags))
/* this currently does wake_up for every dec_ap_bio!
* maybe rather introduce some type of hysteresis?
* e.g. (ap_bio == mxb/2 || ap_bio == 0) ? */
if (ap_bio < mxb)
static inline bool verify_can_do_stop_sector(struct drbd_device *device)
return first_peer_device(device)->connection->agreed_pro_version >= 97 &&
first_peer_device(device)->connection->agreed_pro_version != 100;
static inline int drbd_set_ed_uuid(struct drbd_device *device, u64 val)
int changed = device->ed_uuid != val;
device->ed_uuid = val;
return changed;
static inline int drbd_queue_order_type(struct drbd_device *device)
/* sorry, we currently have no working implementation
* of distributed TCQ stuff */
static inline struct drbd_connection *first_connection(struct drbd_resource *resource)
return list_first_entry_or_null(&resource->connections,
struct drbd_connection, connections);