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| author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2020-12-11 21:39:28 +0300 |
|---|---|---|
| committer | Eric Blake <eblake@redhat.com> | 2021-02-03 08:16:03 -0600 |
| commit | 5ae07b141085c9ac0e10b739639e760b71c490f2 (patch) | |
| tree | ca2e28cf293bbdfd4205c73e19650cbd69edc760 /block/io.c | |
| parent | 17abcbeee24edf264af4250b6e06b07c564e8233 (diff) | |
| download | qemu-5ae07b141085c9ac0e10b739639e760b71c490f2.zip qemu-5ae07b141085c9ac0e10b739639e760b71c490f2.tar.gz qemu-5ae07b141085c9ac0e10b739639e760b71c490f2.tar.bz2 | |
block/io: support int64_t bytes in bdrv_co_do_pwrite_zeroes()
We are generally moving to int64_t for both offset and bytes parameters
on all io paths.
Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.
We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).
So, prepare bdrv_co_do_pwrite_zeroes() now.
Callers are safe, as converting int to int64_t is safe. Concentrate on
'bytes' usage in the function (thx to Eric Blake):
compute 'int tail' via % 'int alignment' - safe
fragmentation loop 'int num' - still fragments with a cap on
max_transfer
use of 'num' within the loop
MIN(bytes, max_transfer) as well as %alignment - still works, so
calculations in if (head) {} are safe
clamp size by 'int max_write_zeroes' - safe
drv->bdrv_co_pwrite_zeroes(int) - safe because of clamping
clamp size by 'int max_transfer' - safe
buf allocation is still clamped to max_transfer
qemu_iovec_init_buf(size_t) - safe because of clamping
bdrv_driver_pwritev(uint64_t) - safe
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-11-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'block/io.c')
| -rw-r--r-- | block/io.c | 8 |
1 files changed, 5 insertions, 3 deletions
@@ -41,7 +41,7 @@ static void bdrv_parent_cb_resize(BlockDriverState *bs); static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, - int64_t offset, int bytes, BdrvRequestFlags flags); + int64_t offset, int64_t bytes, BdrvRequestFlags flags); static void bdrv_parent_drained_begin(BlockDriverState *bs, BdrvChild *ignore, bool ignore_bds_parents) @@ -1819,7 +1819,7 @@ int coroutine_fn bdrv_co_preadv_part(BdrvChild *child, } static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, - int64_t offset, int bytes, BdrvRequestFlags flags) + int64_t offset, int64_t bytes, BdrvRequestFlags flags) { BlockDriver *drv = bs->drv; QEMUIOVector qiov; @@ -1834,6 +1834,8 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, bs->bl.request_alignment); int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer, MAX_BOUNCE_BUFFER); + bdrv_check_request(offset, bytes, &error_abort); + if (!drv) { return -ENOMEDIUM; } @@ -1849,7 +1851,7 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs, assert(max_write_zeroes >= bs->bl.request_alignment); while (bytes > 0 && !ret) { - int num = bytes; + int64_t num = bytes; /* Align request. Block drivers can expect the "bulk" of the request * to be aligned, and that unaligned requests do not cross cluster |