include/sysemu/block-backend.h

   1 /*
   2  * QEMU Block backends
   3  *
   4  * Copyright (C) 2014-2016 Red Hat, Inc.
   5  *
   6  * Authors:
   7  *  Markus Armbruster <armbru@redhat.com>,
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2.1
  10  * or later.  See the COPYING.LIB file in the top-level directory.
  11  */
  12
  13 #ifndef BLOCK_BACKEND_H
  14 #define BLOCK_BACKEND_H
  15
  16 #include "qemu/iov.h"
  17 #include "block/throttle-groups.h"
  18
  19 /*
  20  * TODO Have to include block/block.h for a bunch of block layer
  21  * types.  Unfortunately, this pulls in the whole BlockDriverState
  22  * API, which we don't want used by many BlockBackend users.  Some of
  23  * the types belong here, and the rest should be split into a common
  24  * header and one for the BlockDriverState API.
  25  */
  26 #include "block/block.h"
  27
  28 /* Callbacks for block device models */
  29 typedef struct BlockDevOps {
  30     /*
  31      * Runs when virtual media changed (monitor commands eject, change)
  32      * Argument load is true on load and false on eject.
  33      * Beware: doesn't run when a host device's physical media
  34      * changes.  Sure would be useful if it did.
  35      * Device models with removable media must implement this callback.
  36      */
  37     void (*change_media_cb)(void *opaque, bool load);
  38     /*
  39      * Runs when an eject request is issued from the monitor, the tray
  40      * is closed, and the medium is locked.
  41      * Device models that do not implement is_medium_locked will not need
  42      * this callback.  Device models that can lock the medium or tray might
  43      * want to implement the callback and unlock the tray when "force" is
  44      * true, even if they do not support eject requests.
  45      */
  46     void (*eject_request_cb)(void *opaque, bool force);
  47     /*
  48      * Is the virtual tray open?
  49      * Device models implement this only when the device has a tray.
  50      */
  51     bool (*is_tray_open)(void *opaque);
  52     /*
  53      * Is the virtual medium locked into the device?
  54      * Device models implement this only when device has such a lock.
  55      */
  56     bool (*is_medium_locked)(void *opaque);
  57     /*
  58      * Runs when the size changed (e.g. monitor command block_resize)
  59      */
  60     void (*resize_cb)(void *opaque);
  61 } BlockDevOps;
  62
  63 /* This struct is embedded in (the private) BlockBackend struct and contains
  64  * fields that must be public. This is in particular for QLIST_ENTRY() and
  65  * friends so that BlockBackends can be kept in lists outside block-backend.c */
  66 typedef struct BlockBackendPublic {
  67     /* I/O throttling.
  68      * throttle_state tells us if this BlockBackend has I/O limits configured.
  69      * io_limits_disabled tells us if they are currently being enforced */
  70     CoQueue      throttled_reqs[2];
  71     unsigned int io_limits_disabled;
  72
  73     /* The following fields are protected by the ThrottleGroup lock.
  74      * See the ThrottleGroup documentation for details. */
  75     ThrottleState *throttle_state;
  76     ThrottleTimers throttle_timers;
  77     unsigned       pending_reqs[2];
  78     QLIST_ENTRY(BlockBackendPublic) round_robin;
  79 } BlockBackendPublic;
  80
  81 BlockBackend *blk_new(Error **errp);
  82 BlockBackend *blk_new_with_bs(Error **errp);
  83 BlockBackend *blk_new_open(const char *filename, const char *reference,
  84                            QDict *options, int flags, Error **errp);
  85 int blk_get_refcnt(BlockBackend *blk);
  86 void blk_ref(BlockBackend *blk);
  87 void blk_unref(BlockBackend *blk);
  88 void blk_remove_all_bs(void);
  89 const char *blk_name(BlockBackend *blk);
  90 BlockBackend *blk_by_name(const char *name);
  91 BlockBackend *blk_next(BlockBackend *blk);
  92 BlockDriverState *blk_next_root_bs(BlockDriverState *bs);
  93 bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
  94 void monitor_remove_blk(BlockBackend *blk);
  95
  96 BlockBackendPublic *blk_get_public(BlockBackend *blk);
  97 BlockBackend *blk_by_public(BlockBackendPublic *public);
  98
  99 BlockDriverState *blk_bs(BlockBackend *blk);
 100 void blk_remove_bs(BlockBackend *blk);
 101 void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs);
 102
 103 void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
 104 void blk_iostatus_enable(BlockBackend *blk);
 105 bool blk_iostatus_is_enabled(const BlockBackend *blk);
 106 BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk);
 107 void blk_iostatus_disable(BlockBackend *blk);
 108 void blk_iostatus_reset(BlockBackend *blk);
 109 void blk_iostatus_set_err(BlockBackend *blk, int error);
 110 int blk_attach_dev(BlockBackend *blk, void *dev);
 111 void blk_attach_dev_nofail(BlockBackend *blk, void *dev);
 112 void blk_detach_dev(BlockBackend *blk, void *dev);
 113 void *blk_get_attached_dev(BlockBackend *blk);
 114 void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
 115 int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf,
 116                           int count);
 117 int blk_write_zeroes(BlockBackend *blk, int64_t offset,
 118                      int count, BdrvRequestFlags flags);
 119 BlockAIOCB *blk_aio_write_zeroes(BlockBackend *blk, int64_t offset,
 120                                  int count, BdrvRequestFlags flags,
 121                                  BlockCompletionFunc *cb, void *opaque);
 122 int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count);
 123 int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count,
 124                BdrvRequestFlags flags);
 125 int64_t blk_getlength(BlockBackend *blk);
 126 void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr);
 127 int64_t blk_nb_sectors(BlockBackend *blk);
 128 BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
 129                            QEMUIOVector *qiov, BdrvRequestFlags flags,
 130                            BlockCompletionFunc *cb, void *opaque);
 131 BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
 132                             QEMUIOVector *qiov, BdrvRequestFlags flags,
 133                             BlockCompletionFunc *cb, void *opaque);
 134 BlockAIOCB *blk_aio_flush(BlockBackend *blk,
 135                           BlockCompletionFunc *cb, void *opaque);
 136 BlockAIOCB *blk_aio_discard(BlockBackend *blk,
 137                             int64_t sector_num, int nb_sectors,
 138                             BlockCompletionFunc *cb, void *opaque);
 139 void blk_aio_cancel(BlockAIOCB *acb);
 140 void blk_aio_cancel_async(BlockAIOCB *acb);
 141 int blk_aio_multiwrite(BlockBackend *blk, BlockRequest *reqs, int num_reqs);
 142 int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
 143 BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
 144                           BlockCompletionFunc *cb, void *opaque);
 145 int blk_co_discard(BlockBackend *blk, int64_t sector_num, int nb_sectors);
 146 int blk_co_flush(BlockBackend *blk);
 147 int blk_flush(BlockBackend *blk);
 148 int blk_flush_all(void);
 149 int blk_commit_all(void);
 150 void blk_drain(BlockBackend *blk);
 151 void blk_drain_all(void);
 152 void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
 153                       BlockdevOnError on_write_error);
 154 BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read);
 155 BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
 156                                       int error);
 157 void blk_error_action(BlockBackend *blk, BlockErrorAction action,
 158                       bool is_read, int error);
 159 int blk_is_read_only(BlockBackend *blk);
 160 int blk_is_sg(BlockBackend *blk);
 161 int blk_enable_write_cache(BlockBackend *blk);
 162 void blk_set_enable_write_cache(BlockBackend *blk, bool wce);
 163 void blk_invalidate_cache(BlockBackend *blk, Error **errp);
 164 bool blk_is_inserted(BlockBackend *blk);
 165 bool blk_is_available(BlockBackend *blk);
 166 void blk_lock_medium(BlockBackend *blk, bool locked);
 167 void blk_eject(BlockBackend *blk, bool eject_flag);
 168 int blk_get_flags(BlockBackend *blk);
 169 int blk_get_max_transfer_length(BlockBackend *blk);
 170 int blk_get_max_iov(BlockBackend *blk);
 171 void blk_set_guest_block_size(BlockBackend *blk, int align);
 172 void *blk_try_blockalign(BlockBackend *blk, size_t size);
 173 void *blk_blockalign(BlockBackend *blk, size_t size);
 174 bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp);
 175 void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason);
 176 void blk_op_block_all(BlockBackend *blk, Error *reason);
 177 void blk_op_unblock_all(BlockBackend *blk, Error *reason);
 178 AioContext *blk_get_aio_context(BlockBackend *blk);
 179 void blk_set_aio_context(BlockBackend *blk, AioContext *new_context);
 180 void blk_add_aio_context_notifier(BlockBackend *blk,
 181         void (*attached_aio_context)(AioContext *new_context, void *opaque),
 182         void (*detach_aio_context)(void *opaque), void *opaque);
 183 void blk_remove_aio_context_notifier(BlockBackend *blk,
 184                                      void (*attached_aio_context)(AioContext *,
 185                                                                   void *),
 186                                      void (*detach_aio_context)(void *),
 187                                      void *opaque);
 188 void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify);
 189 void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify);
 190 void blk_io_plug(BlockBackend *blk);
 191 void blk_io_unplug(BlockBackend *blk);
 192 BlockAcctStats *blk_get_stats(BlockBackend *blk);
 193 BlockBackendRootState *blk_get_root_state(BlockBackend *blk);
 194 void blk_update_root_state(BlockBackend *blk);
 195 void blk_apply_root_state(BlockBackend *blk, BlockDriverState *bs);
 196 int blk_get_open_flags_from_root_state(BlockBackend *blk);
 197
 198 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
 199                   BlockCompletionFunc *cb, void *opaque);
 200 int coroutine_fn blk_co_write_zeroes(BlockBackend *blk, int64_t offset,
 201                                      int count, BdrvRequestFlags flags);
 202 int blk_write_compressed(BlockBackend *blk, int64_t sector_num,
 203                          const uint8_t *buf, int nb_sectors);
 204 int blk_truncate(BlockBackend *blk, int64_t offset);
 205 int blk_discard(BlockBackend *blk, int64_t sector_num, int nb_sectors);
 206 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
 207                      int64_t pos, int size);
 208 int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size);
 209 int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz);
 210 int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo);
 211 BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
 212                                   BlockCompletionFunc *cb,
 213                                   void *opaque, int ret);
 214
 215 void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg);
 216 void blk_io_limits_disable(BlockBackend *blk);
 217 void blk_io_limits_enable(BlockBackend *blk, const char *group);
 218 void blk_io_limits_update_group(BlockBackend *blk, const char *group);
 219
 220 #endif