blk/kernel: Fix error code mapping in KernelDevice::read.

pread returns -1 upon error and stores the error code in errno, and thus
the wrong error was being passed into is_expected_ioerr. This is handled
correctly just a few lines down where we return -errno, so it was likely
just an oversight when adapting this logic from the aio codepath, where
the return code is indeed the errno.

This logic has been incorrect since it was introduced in 2018 via
a1e0ece7f987c7a563b25ec0d02fc6f8445ef54e.

Signed-off-by: Joshua Baergen <jbaergen@digitalocean.com>
(cherry picked from commit 5e98a6b959b176b8b3a999e28639437976abb476)

diff --git a/src/blk/kernel/KernelDevice.cc b/src/blk/kernel/KernelDevice.cc
index ee06af61e055f96f425af802a2a8c720d5558e68..e5e3461fb71d2db7b37be8d047791f44ba2a82cb 100644 (file)
--- a/src/blk/kernel/KernelDevice.cc
+++ b/src/blk/kernel/KernelDevice.cc
@@ -1243,7 +1243,7 @@ int KernelDevice::read(uint64_t off, uint64_t len, bufferlist *pbl,
         << "s" << dendl;
   }
   if (r < 0) {
-    if (ioc->allow_eio && is_expected_ioerr(r)) {
+    if (ioc->allow_eio && is_expected_ioerr(-errno)) {
       r = -EIO;
     } else {
       r = -errno;