xref: /openbmc/qemu/include/block/block_int.h (revision 35d08458)
1 /*
2  * QEMU System Emulator block driver
3  *
4  * Copyright (c) 2003 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #ifndef BLOCK_INT_H
25 #define BLOCK_INT_H
26 
27 #include "block/block.h"
28 #include "qemu/option.h"
29 #include "qemu/queue.h"
30 #include "block/coroutine.h"
31 #include "qemu/timer.h"
32 #include "qapi-types.h"
33 #include "qapi/qmp/qerror.h"
34 #include "monitor/monitor.h"
35 #include "qemu/hbitmap.h"
36 #include "block/snapshot.h"
37 #include "qemu/main-loop.h"
38 #include "qemu/throttle.h"
39 
40 #define BLOCK_FLAG_ENCRYPT          1
41 #define BLOCK_FLAG_COMPAT6          4
42 #define BLOCK_FLAG_LAZY_REFCOUNTS   8
43 
44 #define BLOCK_OPT_SIZE              "size"
45 #define BLOCK_OPT_ENCRYPT           "encryption"
46 #define BLOCK_OPT_COMPAT6           "compat6"
47 #define BLOCK_OPT_BACKING_FILE      "backing_file"
48 #define BLOCK_OPT_BACKING_FMT       "backing_fmt"
49 #define BLOCK_OPT_CLUSTER_SIZE      "cluster_size"
50 #define BLOCK_OPT_TABLE_SIZE        "table_size"
51 #define BLOCK_OPT_PREALLOC          "preallocation"
52 #define BLOCK_OPT_SUBFMT            "subformat"
53 #define BLOCK_OPT_COMPAT_LEVEL      "compat"
54 #define BLOCK_OPT_LAZY_REFCOUNTS    "lazy_refcounts"
55 #define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
56 #define BLOCK_OPT_REDUNDANCY        "redundancy"
57 
58 typedef struct BdrvTrackedRequest {
59     BlockDriverState *bs;
60     int64_t offset;
61     unsigned int bytes;
62     bool is_write;
63 
64     bool serialising;
65     int64_t overlap_offset;
66     unsigned int overlap_bytes;
67 
68     QLIST_ENTRY(BdrvTrackedRequest) list;
69     Coroutine *co; /* owner, used for deadlock detection */
70     CoQueue wait_queue; /* coroutines blocked on this request */
71 
72     struct BdrvTrackedRequest *waiting_for;
73 } BdrvTrackedRequest;
74 
75 struct BlockDriver {
76     const char *format_name;
77     int instance_size;
78 
79     /* set to true if the BlockDriver is a block filter */
80     bool is_filter;
81     /* for snapshots block filter like Quorum can implement the
82      * following recursive callback.
83      * It's purpose is to recurse on the filter children while calling
84      * bdrv_recurse_is_first_non_filter on them.
85      * For a sample implementation look in the future Quorum block filter.
86      */
87     bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
88                                              BlockDriverState *candidate);
89 
90     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
91     int (*bdrv_probe_device)(const char *filename);
92 
93     /* Any driver implementing this callback is expected to be able to handle
94      * NULL file names in its .bdrv_open() implementation */
95     void (*bdrv_parse_filename)(const char *filename, QDict *options, Error **errp);
96     /* Drivers not implementing bdrv_parse_filename nor bdrv_open should have
97      * this field set to true, except ones that are defined only by their
98      * child's bs.
99      * An example of the last type will be the quorum block driver.
100      */
101     bool bdrv_needs_filename;
102 
103     /* For handling image reopen for split or non-split files */
104     int (*bdrv_reopen_prepare)(BDRVReopenState *reopen_state,
105                                BlockReopenQueue *queue, Error **errp);
106     void (*bdrv_reopen_commit)(BDRVReopenState *reopen_state);
107     void (*bdrv_reopen_abort)(BDRVReopenState *reopen_state);
108 
109     int (*bdrv_open)(BlockDriverState *bs, QDict *options, int flags,
110                      Error **errp);
111     int (*bdrv_file_open)(BlockDriverState *bs, QDict *options, int flags,
112                           Error **errp);
113     int (*bdrv_read)(BlockDriverState *bs, int64_t sector_num,
114                      uint8_t *buf, int nb_sectors);
115     int (*bdrv_write)(BlockDriverState *bs, int64_t sector_num,
116                       const uint8_t *buf, int nb_sectors);
117     void (*bdrv_close)(BlockDriverState *bs);
118     void (*bdrv_rebind)(BlockDriverState *bs);
119     int (*bdrv_create)(const char *filename, QEMUOptionParameter *options,
120                        Error **errp);
121     int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
122     int (*bdrv_make_empty)(BlockDriverState *bs);
123     /* aio */
124     BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
125         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
126         BlockDriverCompletionFunc *cb, void *opaque);
127     BlockDriverAIOCB *(*bdrv_aio_writev)(BlockDriverState *bs,
128         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
129         BlockDriverCompletionFunc *cb, void *opaque);
130     BlockDriverAIOCB *(*bdrv_aio_flush)(BlockDriverState *bs,
131         BlockDriverCompletionFunc *cb, void *opaque);
132     BlockDriverAIOCB *(*bdrv_aio_discard)(BlockDriverState *bs,
133         int64_t sector_num, int nb_sectors,
134         BlockDriverCompletionFunc *cb, void *opaque);
135 
136     int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
137         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
138     int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
139         int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
140     /*
141      * Efficiently zero a region of the disk image.  Typically an image format
142      * would use a compact metadata representation to implement this.  This
143      * function pointer may be NULL and .bdrv_co_writev() will be called
144      * instead.
145      */
146     int coroutine_fn (*bdrv_co_write_zeroes)(BlockDriverState *bs,
147         int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
148     int coroutine_fn (*bdrv_co_discard)(BlockDriverState *bs,
149         int64_t sector_num, int nb_sectors);
150     int64_t coroutine_fn (*bdrv_co_get_block_status)(BlockDriverState *bs,
151         int64_t sector_num, int nb_sectors, int *pnum);
152 
153     /*
154      * Invalidate any cached meta-data.
155      */
156     void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp);
157 
158     /*
159      * Flushes all data that was already written to the OS all the way down to
160      * the disk (for example raw-posix calls fsync()).
161      */
162     int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs);
163 
164     /*
165      * Flushes all internal caches to the OS. The data may still sit in a
166      * writeback cache of the host OS, but it will survive a crash of the qemu
167      * process.
168      */
169     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
170 
171     const char *protocol_name;
172     int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
173 
174     int64_t (*bdrv_getlength)(BlockDriverState *bs);
175     bool has_variable_length;
176     int64_t (*bdrv_get_allocated_file_size)(BlockDriverState *bs);
177 
178     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
179                                  const uint8_t *buf, int nb_sectors);
180 
181     int (*bdrv_snapshot_create)(BlockDriverState *bs,
182                                 QEMUSnapshotInfo *sn_info);
183     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
184                               const char *snapshot_id);
185     int (*bdrv_snapshot_delete)(BlockDriverState *bs,
186                                 const char *snapshot_id,
187                                 const char *name,
188                                 Error **errp);
189     int (*bdrv_snapshot_list)(BlockDriverState *bs,
190                               QEMUSnapshotInfo **psn_info);
191     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
192                                   const char *snapshot_id,
193                                   const char *name,
194                                   Error **errp);
195     int (*bdrv_get_info)(BlockDriverState *bs, BlockDriverInfo *bdi);
196     ImageInfoSpecific *(*bdrv_get_specific_info)(BlockDriverState *bs);
197 
198     int (*bdrv_save_vmstate)(BlockDriverState *bs, QEMUIOVector *qiov,
199                              int64_t pos);
200     int (*bdrv_load_vmstate)(BlockDriverState *bs, uint8_t *buf,
201                              int64_t pos, int size);
202 
203     int (*bdrv_change_backing_file)(BlockDriverState *bs,
204         const char *backing_file, const char *backing_fmt);
205 
206     /* removable device specific */
207     int (*bdrv_is_inserted)(BlockDriverState *bs);
208     int (*bdrv_media_changed)(BlockDriverState *bs);
209     void (*bdrv_eject)(BlockDriverState *bs, bool eject_flag);
210     void (*bdrv_lock_medium)(BlockDriverState *bs, bool locked);
211 
212     /* to control generic scsi devices */
213     int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
214     BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
215         unsigned long int req, void *buf,
216         BlockDriverCompletionFunc *cb, void *opaque);
217 
218     /* List of options for creating images, terminated by name == NULL */
219     QEMUOptionParameter *create_options;
220 
221 
222     /*
223      * Returns 0 for completed check, -errno for internal errors.
224      * The check results are stored in result.
225      */
226     int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
227         BdrvCheckMode fix);
228 
229     int (*bdrv_amend_options)(BlockDriverState *bs,
230         QEMUOptionParameter *options);
231 
232     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
233 
234     /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
235     int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
236         const char *tag);
237     int (*bdrv_debug_remove_breakpoint)(BlockDriverState *bs,
238         const char *tag);
239     int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
240     bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
241 
242     int (*bdrv_refresh_limits)(BlockDriverState *bs);
243 
244     /*
245      * Returns 1 if newly created images are guaranteed to contain only
246      * zeros, 0 otherwise.
247      */
248     int (*bdrv_has_zero_init)(BlockDriverState *bs);
249 
250     QLIST_ENTRY(BlockDriver) list;
251 };
252 
253 typedef struct BlockLimits {
254     /* maximum number of sectors that can be discarded at once */
255     int max_discard;
256 
257     /* optimal alignment for discard requests in sectors */
258     int64_t discard_alignment;
259 
260     /* maximum number of sectors that can zeroized at once */
261     int max_write_zeroes;
262 
263     /* optimal alignment for write zeroes requests in sectors */
264     int64_t write_zeroes_alignment;
265 
266     /* optimal transfer length in sectors */
267     int opt_transfer_length;
268 
269     /* memory alignment so that no bounce buffer is needed */
270     size_t opt_mem_alignment;
271 } BlockLimits;
272 
273 /*
274  * Note: the function bdrv_append() copies and swaps contents of
275  * BlockDriverStates, so if you add new fields to this struct, please
276  * inspect bdrv_append() to determine if the new fields need to be
277  * copied as well.
278  */
279 struct BlockDriverState {
280     int64_t total_sectors; /* if we are reading a disk image, give its
281                               size in sectors */
282     int read_only; /* if true, the media is read only */
283     int open_flags; /* flags used to open the file, re-used for re-open */
284     int encrypted; /* if true, the media is encrypted */
285     int valid_key; /* if true, a valid encryption key has been set */
286     int sg;        /* if true, the device is a /dev/sg* */
287     int copy_on_read; /* if true, copy read backing sectors into image
288                          note this is a reference count */
289 
290     BlockDriver *drv; /* NULL means no media */
291     void *opaque;
292 
293     void *dev;                  /* attached device model, if any */
294     /* TODO change to DeviceState when all users are qdevified */
295     const BlockDevOps *dev_ops;
296     void *dev_opaque;
297 
298     char filename[1024];
299     char backing_file[1024]; /* if non zero, the image is a diff of
300                                 this file image */
301     char backing_format[16]; /* if non-zero and backing_file exists */
302 
303     BlockDriverState *backing_hd;
304     BlockDriverState *file;
305 
306     NotifierList close_notifiers;
307 
308     /* Callback before write request is processed */
309     NotifierWithReturnList before_write_notifiers;
310 
311     /* number of in-flight serialising requests */
312     unsigned int serialising_in_flight;
313 
314     /* I/O throttling */
315     ThrottleState throttle_state;
316     CoQueue      throttled_reqs[2];
317     bool         io_limits_enabled;
318 
319     /* I/O stats (display with "info blockstats"). */
320     uint64_t nr_bytes[BDRV_MAX_IOTYPE];
321     uint64_t nr_ops[BDRV_MAX_IOTYPE];
322     uint64_t total_time_ns[BDRV_MAX_IOTYPE];
323     uint64_t wr_highest_sector;
324 
325     /* I/O Limits */
326     BlockLimits bl;
327 
328     /* Whether the disk can expand beyond total_sectors */
329     int growable;
330 
331     /* Whether produces zeros when read beyond eof */
332     bool zero_beyond_eof;
333 
334     /* Alignment requirement for offset/length of I/O requests */
335     unsigned int request_alignment;
336 
337     /* the block size for which the guest device expects atomicity */
338     int guest_block_size;
339 
340     /* do we need to tell the quest if we have a volatile write cache? */
341     int enable_write_cache;
342 
343     /* NOTE: the following infos are only hints for real hardware
344        drivers. They are not used by the block driver */
345     BlockdevOnError on_read_error, on_write_error;
346     bool iostatus_enabled;
347     BlockDeviceIoStatus iostatus;
348 
349     /* the following member gives a name to every node on the bs graph. */
350     char node_name[32];
351     /* element of the list of named nodes building the graph */
352     QTAILQ_ENTRY(BlockDriverState) node_list;
353     /* Device name is the name associated with the "drive" the guest sees */
354     char device_name[32];
355     /* element of the list of "drives" the guest sees */
356     QTAILQ_ENTRY(BlockDriverState) device_list;
357     QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
358     int refcnt;
359     int in_use; /* users other than guest access, eg. block migration */
360 
361     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
362 
363     /* long-running background operation */
364     BlockJob *job;
365 
366     QDict *options;
367 };
368 
369 int get_tmp_filename(char *filename, int size);
370 
371 void bdrv_set_io_limits(BlockDriverState *bs,
372                         ThrottleConfig *cfg);
373 
374 
375 /**
376  * bdrv_add_before_write_notifier:
377  *
378  * Register a callback that is invoked before write requests are processed but
379  * after any throttling or waiting for overlapping requests.
380  */
381 void bdrv_add_before_write_notifier(BlockDriverState *bs,
382                                     NotifierWithReturn *notifier);
383 
384 /**
385  * bdrv_get_aio_context:
386  *
387  * Returns: the currently bound #AioContext
388  */
389 AioContext *bdrv_get_aio_context(BlockDriverState *bs);
390 
391 #ifdef _WIN32
392 int is_windows_drive(const char *filename);
393 #endif
394 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
395                                enum MonitorEvent ev,
396                                BlockErrorAction action, bool is_read);
397 
398 /**
399  * stream_start:
400  * @bs: Block device to operate on.
401  * @base: Block device that will become the new base, or %NULL to
402  * flatten the whole backing file chain onto @bs.
403  * @base_id: The file name that will be written to @bs as the new
404  * backing file if the job completes.  Ignored if @base is %NULL.
405  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
406  * @on_error: The action to take upon error.
407  * @cb: Completion function for the job.
408  * @opaque: Opaque pointer value passed to @cb.
409  * @errp: Error object.
410  *
411  * Start a streaming operation on @bs.  Clusters that are unallocated
412  * in @bs, but allocated in any image between @base and @bs (both
413  * exclusive) will be written to @bs.  At the end of a successful
414  * streaming job, the backing file of @bs will be changed to
415  * @base_id in the written image and to @base in the live BlockDriverState.
416  */
417 void stream_start(BlockDriverState *bs, BlockDriverState *base,
418                   const char *base_id, int64_t speed, BlockdevOnError on_error,
419                   BlockDriverCompletionFunc *cb,
420                   void *opaque, Error **errp);
421 
422 /**
423  * commit_start:
424  * @bs: Active block device.
425  * @top: Top block device to be committed.
426  * @base: Block device that will be written into, and become the new top.
427  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
428  * @on_error: The action to take upon error.
429  * @cb: Completion function for the job.
430  * @opaque: Opaque pointer value passed to @cb.
431  * @errp: Error object.
432  *
433  */
434 void commit_start(BlockDriverState *bs, BlockDriverState *base,
435                  BlockDriverState *top, int64_t speed,
436                  BlockdevOnError on_error, BlockDriverCompletionFunc *cb,
437                  void *opaque, Error **errp);
438 /**
439  * commit_active_start:
440  * @bs: Active block device to be committed.
441  * @base: Block device that will be written into, and become the new top.
442  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
443  * @on_error: The action to take upon error.
444  * @cb: Completion function for the job.
445  * @opaque: Opaque pointer value passed to @cb.
446  * @errp: Error object.
447  *
448  */
449 void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
450                          int64_t speed,
451                          BlockdevOnError on_error,
452                          BlockDriverCompletionFunc *cb,
453                          void *opaque, Error **errp);
454 /*
455  * mirror_start:
456  * @bs: Block device to operate on.
457  * @target: Block device to write to.
458  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
459  * @granularity: The chosen granularity for the dirty bitmap.
460  * @buf_size: The amount of data that can be in flight at one time.
461  * @mode: Whether to collapse all images in the chain to the target.
462  * @on_source_error: The action to take upon error reading from the source.
463  * @on_target_error: The action to take upon error writing to the target.
464  * @cb: Completion function for the job.
465  * @opaque: Opaque pointer value passed to @cb.
466  * @errp: Error object.
467  *
468  * Start a mirroring operation on @bs.  Clusters that are allocated
469  * in @bs will be written to @bs until the job is cancelled or
470  * manually completed.  At the end of a successful mirroring job,
471  * @bs will be switched to read from @target.
472  */
473 void mirror_start(BlockDriverState *bs, BlockDriverState *target,
474                   int64_t speed, int64_t granularity, int64_t buf_size,
475                   MirrorSyncMode mode, BlockdevOnError on_source_error,
476                   BlockdevOnError on_target_error,
477                   BlockDriverCompletionFunc *cb,
478                   void *opaque, Error **errp);
479 
480 /*
481  * backup_start:
482  * @bs: Block device to operate on.
483  * @target: Block device to write to.
484  * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
485  * @sync_mode: What parts of the disk image should be copied to the destination.
486  * @on_source_error: The action to take upon error reading from the source.
487  * @on_target_error: The action to take upon error writing to the target.
488  * @cb: Completion function for the job.
489  * @opaque: Opaque pointer value passed to @cb.
490  *
491  * Start a backup operation on @bs.  Clusters in @bs are written to @target
492  * until the job is cancelled or manually completed.
493  */
494 void backup_start(BlockDriverState *bs, BlockDriverState *target,
495                   int64_t speed, MirrorSyncMode sync_mode,
496                   BlockdevOnError on_source_error,
497                   BlockdevOnError on_target_error,
498                   BlockDriverCompletionFunc *cb, void *opaque,
499                   Error **errp);
500 
501 #endif /* BLOCK_INT_H */
502