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c33159dec7
This patch is purely mechanical, changing bool want_zero into an unsigned int for bitwise-or of flags. As of this patch, all implementations are unchanged (the old want_zero==true is now mode==BDRV_WANT_PRECISE which is a superset of BDRV_WANT_ZERO); but the callers in io.c that used to pass want_zero==false are now prepared for future driver changes that can now distinguish bewteen BDRV_WANT_ZERO vs. BDRV_WANT_ALLOCATED. The next patch will actually change the file-posix driver along those lines, now that we have more-specific hints. As for the background why this patch is useful: right now, the file-posix driver recognizes that if allocation is being queried, the entire image can be reported as allocated (there is no backing file to refer to) - but this throws away information on whether the entire image reads as zero (trivially true if lseek(SEEK_HOLE) at offset 0 returns -ENXIO, a bit more complicated to prove if the raw file was created with 'qemu-img create' since we intentionally allocate a small chunk of all-zero data to help with alignment probing). Later patches will add a generic algorithm for seeing if an entire file reads as zeroes. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20250509204341.3553601-16-eblake@redhat.com> |
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| .. | ||
| accounting.h | ||
| aio-wait.h | ||
| aio.h | ||
| aio_task.h | ||
| block-common.h | ||
| block-copy.h | ||
| block-global-state.h | ||
| block-hmp-cmds.h | ||
| block-io.h | ||
| block.h | ||
| block_backup.h | ||
| block_int-common.h | ||
| block_int-global-state.h | ||
| block_int-io.h | ||
| block_int.h | ||
| blockjob.h | ||
| blockjob_int.h | ||
| dirty-bitmap.h | ||
| export.h | ||
| fuse.h | ||
| graph-lock.h | ||
| nbd.h | ||
| nvme.h | ||
| qapi.h | ||
| qdict.h | ||
| raw-aio.h | ||
| replication.h | ||
| reqlist.h | ||
| snapshot.h | ||
| thread-pool.h | ||
| throttle-groups.h | ||
| ufs.h | ||
| write-threshold.h | ||