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From 4b6c9d80b06057886e35650b904fe332ae14d0bd Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Wed, 4 Dec 2013 12:13:10 +0100
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Subject: [PATCH 19/37] block: Make zero-after-EOF work with larger alignment
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Message-id: <1392117622-28812-20-git-send-email-kwolf@redhat.com>
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Patchwork-id: 57184
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O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 19/37] block: Make zero-after-EOF work with larger alignment
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Bugzilla: 748906
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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Odd file sizes could make bdrv_aligned_preadv() shorten the request in
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non-aligned ways. Fix it by rounding to the required alignment instead
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of 512 bytes.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Reviewed-by: Benoit Canet <benoit@irqsave.net>
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(cherry picked from commit ec746e10cb2e6276a8d2e036454792fe0674864a)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 block.c | 7 ++++---
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 1 file changed, 4 insertions(+), 3 deletions(-)
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---
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 block.c |    7 ++++---
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 1 files changed, 4 insertions(+), 3 deletions(-)
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diff --git a/block.c b/block.c
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index feeab4e..6317321 100644
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--- a/block.c
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+++ b/block.c
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@@ -2748,7 +2748,7 @@ err:
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  */
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 static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
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     BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
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-    QEMUIOVector *qiov, int flags)
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+    int64_t align, QEMUIOVector *qiov, int flags)
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 {
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     BlockDriver *drv = bs->drv;
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     int ret;
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@@ -2796,7 +2796,8 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
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         }
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         total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE);
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-        max_nb_sectors = MAX(0, total_sectors - sector_num);
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+        max_nb_sectors = MAX(0, ROUND_UP(total_sectors - sector_num,
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+                                         align >> BDRV_SECTOR_BITS));
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         if (max_nb_sectors > 0) {
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             ret = drv->bdrv_co_readv(bs, sector_num,
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                                      MIN(nb_sectors, max_nb_sectors), qiov);
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@@ -2882,7 +2883,7 @@ static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
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     }
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     tracked_request_begin(&req, bs, offset, bytes, false);
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-    ret = bdrv_aligned_preadv(bs, &req, offset, bytes,
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+    ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align,
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                               use_local_qiov ? &local_qiov : qiov,
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                               flags);
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     tracked_request_end(&req);
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-- 
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1.7.1
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