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, Error **errp); 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 /* 62 * Runs when the backend receives a drain request. 63 */ 64 void (*drained_begin)(void *opaque); 65 /* 66 * Runs when the backend's last drain request ends. 67 */ 68 void (*drained_end)(void *opaque); 69 } BlockDevOps; 70 71 /* This struct is embedded in (the private) BlockBackend struct and contains 72 * fields that must be public. This is in particular for QLIST_ENTRY() and 73 * friends so that BlockBackends can be kept in lists outside block-backend.c */ 74 typedef struct BlockBackendPublic { 75 /* throttled_reqs_lock protects the CoQueues for throttled requests. */ 76 CoMutex throttled_reqs_lock; 77 CoQueue throttled_reqs[2]; 78 79 /* Nonzero if the I/O limits are currently being ignored; generally 80 * it is zero. Accessed with atomic operations. 81 */ 82 unsigned int io_limits_disabled; 83 84 /* The following fields are protected by the ThrottleGroup lock. 85 * See the ThrottleGroup documentation for details. 86 * throttle_state tells us if I/O limits are configured. */ 87 ThrottleState *throttle_state; 88 ThrottleTimers throttle_timers; 89 unsigned pending_reqs[2]; 90 QLIST_ENTRY(BlockBackendPublic) round_robin; 91 } BlockBackendPublic; 92 93 BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm); 94 BlockBackend *blk_new_open(const char *filename, const char *reference, 95 QDict *options, int flags, Error **errp); 96 int blk_get_refcnt(BlockBackend *blk); 97 void blk_ref(BlockBackend *blk); 98 void blk_unref(BlockBackend *blk); 99 void blk_remove_all_bs(void); 100 const char *blk_name(const BlockBackend *blk); 101 BlockBackend *blk_by_name(const char *name); 102 BlockBackend *blk_next(BlockBackend *blk); 103 BlockBackend *blk_all_next(BlockBackend *blk); 104 bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp); 105 void monitor_remove_blk(BlockBackend *blk); 106 107 BlockBackendPublic *blk_get_public(BlockBackend *blk); 108 BlockBackend *blk_by_public(BlockBackendPublic *public); 109 110 BlockDriverState *blk_bs(BlockBackend *blk); 111 void blk_remove_bs(BlockBackend *blk); 112 int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp); 113 bool bdrv_has_blk(BlockDriverState *bs); 114 bool bdrv_is_root_node(BlockDriverState *bs); 115 int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm, 116 Error **errp); 117 void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm); 118 119 void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow); 120 void blk_iostatus_enable(BlockBackend *blk); 121 bool blk_iostatus_is_enabled(const BlockBackend *blk); 122 BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk); 123 void blk_iostatus_disable(BlockBackend *blk); 124 void blk_iostatus_reset(BlockBackend *blk); 125 void blk_iostatus_set_err(BlockBackend *blk, int error); 126 int blk_attach_dev(BlockBackend *blk, DeviceState *dev); 127 void blk_attach_dev_legacy(BlockBackend *blk, void *dev); 128 void blk_detach_dev(BlockBackend *blk, void *dev); 129 void *blk_get_attached_dev(BlockBackend *blk); 130 char *blk_get_attached_dev_id(BlockBackend *blk); 131 BlockBackend *blk_by_dev(void *dev); 132 BlockBackend *blk_by_qdev_id(const char *id, Error **errp); 133 void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque); 134 int blk_pread_unthrottled(BlockBackend *blk, int64_t offset, uint8_t *buf, 135 int bytes); 136 int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset, 137 unsigned int bytes, QEMUIOVector *qiov, 138 BdrvRequestFlags flags); 139 int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, 140 unsigned int bytes, QEMUIOVector *qiov, 141 BdrvRequestFlags flags); 142 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset, 143 int bytes, BdrvRequestFlags flags); 144 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset, 145 int bytes, BdrvRequestFlags flags, 146 BlockCompletionFunc *cb, void *opaque); 147 int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags); 148 int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes); 149 int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes, 150 BdrvRequestFlags flags); 151 int64_t blk_getlength(BlockBackend *blk); 152 void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr); 153 int64_t blk_nb_sectors(BlockBackend *blk); 154 BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset, 155 QEMUIOVector *qiov, BdrvRequestFlags flags, 156 BlockCompletionFunc *cb, void *opaque); 157 BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset, 158 QEMUIOVector *qiov, BdrvRequestFlags flags, 159 BlockCompletionFunc *cb, void *opaque); 160 BlockAIOCB *blk_aio_flush(BlockBackend *blk, 161 BlockCompletionFunc *cb, void *opaque); 162 BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int bytes, 163 BlockCompletionFunc *cb, void *opaque); 164 void blk_aio_cancel(BlockAIOCB *acb); 165 void blk_aio_cancel_async(BlockAIOCB *acb); 166 int blk_co_ioctl(BlockBackend *blk, unsigned long int req, void *buf); 167 int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf); 168 BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf, 169 BlockCompletionFunc *cb, void *opaque); 170 int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes); 171 int blk_co_flush(BlockBackend *blk); 172 int blk_flush(BlockBackend *blk); 173 int blk_commit_all(void); 174 void blk_drain(BlockBackend *blk); 175 void blk_drain_all(void); 176 void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error, 177 BlockdevOnError on_write_error); 178 BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read); 179 BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read, 180 int error); 181 void blk_error_action(BlockBackend *blk, BlockErrorAction action, 182 bool is_read, int error); 183 int blk_is_read_only(BlockBackend *blk); 184 int blk_is_sg(BlockBackend *blk); 185 int blk_enable_write_cache(BlockBackend *blk); 186 void blk_set_enable_write_cache(BlockBackend *blk, bool wce); 187 void blk_invalidate_cache(BlockBackend *blk, Error **errp); 188 bool blk_is_inserted(BlockBackend *blk); 189 bool blk_is_available(BlockBackend *blk); 190 void blk_lock_medium(BlockBackend *blk, bool locked); 191 void blk_eject(BlockBackend *blk, bool eject_flag); 192 int blk_get_flags(BlockBackend *blk); 193 uint32_t blk_get_max_transfer(BlockBackend *blk); 194 int blk_get_max_iov(BlockBackend *blk); 195 void blk_set_guest_block_size(BlockBackend *blk, int align); 196 void *blk_try_blockalign(BlockBackend *blk, size_t size); 197 void *blk_blockalign(BlockBackend *blk, size_t size); 198 bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp); 199 void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason); 200 void blk_op_block_all(BlockBackend *blk, Error *reason); 201 void blk_op_unblock_all(BlockBackend *blk, Error *reason); 202 AioContext *blk_get_aio_context(BlockBackend *blk); 203 void blk_set_aio_context(BlockBackend *blk, AioContext *new_context); 204 void blk_add_aio_context_notifier(BlockBackend *blk, 205 void (*attached_aio_context)(AioContext *new_context, void *opaque), 206 void (*detach_aio_context)(void *opaque), void *opaque); 207 void blk_remove_aio_context_notifier(BlockBackend *blk, 208 void (*attached_aio_context)(AioContext *, 209 void *), 210 void (*detach_aio_context)(void *), 211 void *opaque); 212 void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify); 213 void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify); 214 void blk_io_plug(BlockBackend *blk); 215 void blk_io_unplug(BlockBackend *blk); 216 BlockAcctStats *blk_get_stats(BlockBackend *blk); 217 BlockBackendRootState *blk_get_root_state(BlockBackend *blk); 218 void blk_update_root_state(BlockBackend *blk); 219 bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk); 220 int blk_get_open_flags_from_root_state(BlockBackend *blk); 221 222 void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk, 223 BlockCompletionFunc *cb, void *opaque); 224 int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset, 225 int bytes, BdrvRequestFlags flags); 226 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf, 227 int bytes); 228 int blk_truncate(BlockBackend *blk, int64_t offset, PreallocMode prealloc, 229 Error **errp); 230 int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes); 231 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf, 232 int64_t pos, int size); 233 int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size); 234 int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz); 235 int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo); 236 BlockAIOCB *blk_abort_aio_request(BlockBackend *blk, 237 BlockCompletionFunc *cb, 238 void *opaque, int ret); 239 240 void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg); 241 void blk_io_limits_disable(BlockBackend *blk); 242 void blk_io_limits_enable(BlockBackend *blk, const char *group); 243 void blk_io_limits_update_group(BlockBackend *blk, const char *group); 244 245 #endif 246