[pve-devel] [PATCH qemu] add patch fixing io_uring short read slow path

Fabian Ebner f.ebner at proxmox.com
Fri Jul 1 10:39:39 CEST 2022


Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
---
 ...20-io_uring-fix-short-read-slow-path.patch | 47 +++++++++++++++++++
 debian/patches/series                         |  1 +
 2 files changed, 48 insertions(+)
 create mode 100644 debian/patches/extra/0020-io_uring-fix-short-read-slow-path.patch

diff --git a/debian/patches/extra/0020-io_uring-fix-short-read-slow-path.patch b/debian/patches/extra/0020-io_uring-fix-short-read-slow-path.patch
new file mode 100644
index 0000000..6078d00
--- /dev/null
+++ b/debian/patches/extra/0020-io_uring-fix-short-read-slow-path.patch
@@ -0,0 +1,47 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Dominique Martinet <dominique.martinet at atmark-techno.com>
+Date: Thu, 30 Jun 2022 10:01:37 +0900
+Subject: [PATCH] io_uring: fix short read slow path
+
+sqeq.off here is the offset to read within the disk image, so obviously
+not 'nread' (the amount we just read), but as the author meant to write
+its current value incremented by the amount we just read.
+
+Normally recent versions of linux will not issue short reads,
+but it can happen so we should fix this.
+
+This lead to weird image corruptions when short read happened
+
+Fixes: 6663a0a33764 ("block/io_uring: implements interfaces for io_uring")
+Link: https://lkml.kernel.org/r/YrrFGO4A1jS0GI0G@atmark-techno.com
+Reviewed-by: Hanna Reitz <hreitz at redhat.com>
+Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>
+Signed-off-by: Dominique Martinet <dominique.martinet at atmark-techno.com>
+(taken from https://lists.nongnu.org/archive/html/qemu-devel/2022-06/msg05619.html)
+Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
+---
+ block/io_uring.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/block/io_uring.c b/block/io_uring.c
+index 782afdb433..e451e55de0 100644
+--- a/block/io_uring.c
++++ b/block/io_uring.c
+@@ -89,7 +89,7 @@ static void luring_resubmit_short_read(LuringState *s, LuringAIOCB *luringcb,
+     trace_luring_resubmit_short_read(s, luringcb, nread);
+ 
+     /* Update read position */
+-    luringcb->total_read = nread;
++    luringcb->total_read += nread;
+     remaining = luringcb->qiov->size - luringcb->total_read;
+ 
+     /* Shorten qiov */
+@@ -103,7 +103,7 @@ static void luring_resubmit_short_read(LuringState *s, LuringAIOCB *luringcb,
+                       remaining);
+ 
+     /* Update sqe */
+-    luringcb->sqeq.off = nread;
++    luringcb->sqeq.off += nread;
+     luringcb->sqeq.addr = (__u64)(uintptr_t)luringcb->resubmit_qiov.iov;
+     luringcb->sqeq.len = luringcb->resubmit_qiov.niov;
+ 
diff --git a/debian/patches/series b/debian/patches/series
index 3850a52..146b27e 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -17,6 +17,7 @@ extra/0016-vdpa-Fix-bad-index-calculus-at-vhost_vdpa_get_vring_.patch
 extra/0017-vdpa-Fix-index-calculus-at-vhost_vdpa_svqs_start.patch
 extra/0018-hw-virtio-Replace-g_memdup-by-g_memdup2.patch
 extra/0019-vhost-Fix-element-in-vhost_svq_add-failure.patch
+extra/0020-io_uring-fix-short-read-slow-path.patch
 bitmap-mirror/0001-drive-mirror-add-support-for-sync-bitmap-mode-never.patch
 bitmap-mirror/0002-drive-mirror-add-support-for-conditional-and-always-.patch
 bitmap-mirror/0003-mirror-add-check-for-bitmap-mode-without-bitmap.patch
-- 
2.30.2





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