include/block/block_int-common.h

28 #include "block/block-common.h"
29 #include "block/block-global-state.h"
48 #define BLOCK_OPT_COMPAT_LEVEL      "compat"
105      * certain callbacks that refer to data (see block.c) to their bs->file
106      * or bs->backing (whichever one exists) if the driver doesn't implement
108      * -ENOTSUP.
115      * (And this filtered child must then be bs->file or bs->backing.)
120      * If true, filtered child is bs->backing. Otherwise it's bs->file.
121      * Two internal filters use bs->backing as filtered child and has this
123      * filters in tests/unit/test-bdrv-graph-mod.c.
128      * similarly using bs->file as filtered child.
157      *  - Return status 0 of .bdrv_co_block_status means that corresponding
158      *    blocks are not allocated in this layer of backing-chain
159      *  - For such (unallocated) blocks, read will:
160      *    - fill buffer with zeros if there is no backing file
161      *    - read from the backing file otherwise, where the block layer
182      * NULL-terminated list of the runtime options that can be
190      * Pointer to a NULL-terminated array of names of strong options
202      * See include/block/block-global-state.h for more information about
209      * to allow driver-specific initialization code that requires
237     /* For handling image reopen for split or non-split files. */
267      * Refreshes the bs->exact_filename field. If that is impossible,
268      * bs->exact_filename has to be left empty.
277      *     QINCREF(bs->file->bs->full_open_options);
278      *     qdict_put(target, "file", bs->file->bs->full_open_options);
283      * @backing_overridden is true when bs->backing seems not to be
284      * the child that would result from opening bs->backing_file.
305      * of in-flight requests, so don't waste the time if possible.
308      * timeout during job-cancel with force=true.
354      * loop is no longer in use.  Called with no in-flight requests and in
355      * depth-first traversal order with parents before child nodes.
361      * can be processed again.  Called with no in-flight requests and in
362      * depth-first traversal order with child nodes before parent nodes.
392      * On failure return -errno.
431      * If both conditions are met, 0 is returned. Otherwise, -errno is returned
456      * bdrv_check_perm() call. It is a no-op then.
468      * If @reopen_queue is non-NULL, don't return the currently needed
499      * I/O API functions. These functions are thread-safe.
501      * See include/block/block-io.h for more information about
578      * function pointer may be NULL or return -ENOSUP and .bdrv_co_writev()
605      * -ENOTSUP if @bs is the leaf but @src has a different BlockDriver.
623      * non-zero results.  See block.h for the overall meaning of the
624      * bits.  As a hint, the flags in @mode may include a bitwise-or
629      * non-NULL pnum, map, and file; in turn, the driver must return
630      * an error or set pnum to an aligned non-zero value.
638      * *pnum value for the block-status cache on protocol nodes, prior
647      * Snapshot-access API.
649      * Block-driver may provide snapshot-access API: special functions to access
652      * in generic block-layer: no serializing, no alignment, no tracked
653      * requests. So, block-driver that realizes these APIs is fully responsible
654      * for synchronization between snapshot-access API and normal IO requests.
658      * - be able to select a specific snapshot
659      * - receive the snapshot's actual length (which may differ from bs's
674      * Invalidate any cached meta-data.
692      * the disk (for example file-posix.c calls fsync()).
716      * with @exact = false, it should return -ENOTSUP.
778      * Returns 0 for completed check, -errno for internal errors.
799     return drv->bdrv_co_pwritev_compressed ||  in block_driver_can_compress()
800            drv->bdrv_co_pwritev_compressed_part;  in block_driver_can_compress()
815      * inherent 64-bit limit.
852      * for no 32-bit limit.  For now, anything larger than INT_MAX is
885      * is expected to adjust automatically.  Mostly for CD-ROM drives,
935      * non-BDS parents.
942      * See include/block/block-global-state.h for more information about
952      * human reader. This could be a node-name, BlockBackend name, qdev ID or
960      * when migration is completing) and it can start/stop requesting
1017      * I/O API functions. These functions are thread-safe.
1019      * See include/block/block-io.h for more information about
1063      * (through klass->drained_*).
1065      * It is generally true if bs->quiesce_counter > 0. It may differ while the
1094      * Protected by big QEMU lock or read-only after opening.  No special
1097     int open_flags; /* flags used to open the file, re-used for re-open */
1109      * long-running tasks intended to always use the same AioContext as this
1120      * therefore may or may not be equal to .backing->bs->filename.
1132     char backing_format[16]; /* if non-zero and backing_file exists */
1157      * every incoming write request as-is, including potentially that
1182     /* element of the list of monitor-owned BDS */
1219      * Generally read-only; it is written to by load_snapshot and
1241      * than one client has requested copy-on-read.  Accessed with atomic
1247      * number of in-flight requests; overall and serialising.
1273     /* Lock for block-status cache RCU writers */
1275     /* Always non-NULL, but must only be dereferenced under an RCU read guard */
1290      * - sync=full: Set backing BDS to NULL.
1291      * - sync=top:  Use source's backing BDS.
1292      * - sync=none: Use source as the backing BDS.
1316  * Common functions that are neither I/O nor Global State.
1318  * See include/block/block-common.h for more information about
1319  * the Common API.
1324     return child ? child->bs : NULL;  in child_bs()