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From 8c14192b6417a5f07658c9434c10c4fb296574c8 Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Fri, 29 Jun 2018 06:11:53 +0200
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Subject: [PATCH 179/268] file-posix: Fix EINTR handling
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RH-Author: Fam Zheng <famz@redhat.com>
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Message-id: <20180629061153.12687-14-famz@redhat.com>
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Patchwork-id: 81164
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O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH v2 13/13] file-posix: Fix EINTR handling
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Bugzilla: 1482537
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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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RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
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EINTR should be checked against errno, not ret. While fixing the bug,
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collect the branches with a switch block.
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Also, change the return value from -ENOSTUP to -ENOSPC when the actual
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issue is request range passes EOF, which should be distinguishable from
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the case of error == ENOSYS by the caller, so that it could still retry
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with other byte ranges, whereas it shouldn't retry anymore upon ENOSYS.
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 block/file-posix.c | 17 +++++++++--------
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 1 file changed, 9 insertions(+), 8 deletions(-)
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diff --git a/block/file-posix.c b/block/file-posix.c
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index 29ff699..0a9df5b 100644
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--- a/block/file-posix.c
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+++ b/block/file-posix.c
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@@ -1449,20 +1449,21 @@ static ssize_t handle_aiocb_copy_range(RawPosixAIOData *aiocb)
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         ssize_t ret = copy_file_range(aiocb->aio_fildes, &in_off,
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                                       aiocb->aio_fd2, &out_off,
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                                       bytes, 0);
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-        if (ret == -EINTR) {
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-            continue;
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+        if (ret == 0) {
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+            /* No progress (e.g. when beyond EOF), let the caller fall back to
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+             * buffer I/O. */
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+            return -ENOSPC;
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         }
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         if (ret < 0) {
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-            if (errno == ENOSYS) {
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+            switch (errno) {
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+            case ENOSYS:
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                 return -ENOTSUP;
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-            } else {
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+            case EINTR:
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+                continue;
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+            default:
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                 return -errno;
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             }
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         }
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-        if (!ret) {
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-            /* No progress (e.g. when beyond EOF), fall back to buffer I/O. */
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-            return -ENOTSUP;
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-        }
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         bytes -= ret;
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     }
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     return 0;
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-- 
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1.8.3.1
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