From 221a94a66c4d2f6e4f2dc938ee8a63a6ca739477 Mon Sep 17 00:00:00 2001
From: Ahmad Samir <a.samirh78@gmail.com>
Date: Wed, 20 Oct 2021 20:01:40 +0200
Subject: [PATCH] KMountPoint: revert to parsing /dev/disk/by-{uuid,label}/
 manually

Apparently libblkid is causing some performance issues when resolving
UUID/LABEL tags from fstab when the device that has that UUID/LABEL isn't
present.

Parsing /dev/disk/by-* is more basic, since it's a simple check resolving
some symlinks.

Thanks to the users in the bug report for the investigative work, because
personally I couldn't reproduce the problem on my machine no matter what I
tried.

BUG: 442106
FIXED-IN: 5.88
---
 CMakeLists.txt                      |  3 +--
 src/core/CMakeLists.txt             |  5 ++---
 src/core/config-kmountpoint.h.cmake |  2 +-
 src/core/kmountpoint.cpp            | 18 ++++--------------
 4 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca374a4cb..f1bb1a59b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -130,8 +130,7 @@ set_package_properties(ACL PROPERTIES DESCRIPTION "LibACL"
 # Used by KMountPoint
 if (CMAKE_SYSTEM_NAME MATCHES "Linux")
     find_package(LibMount REQUIRED)
-    find_package(Blkid REQUIRED)
-    set(HAVE_LIBS_MOUNT_AND_BLKID ${LibMount_FOUND} AND ${Blkid_FOUND})
+    set(HAVE_LIB_MOUNT ${LibMount_FOUND})
 endif()
 
 if (ANDROID)
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index be19e9b62..67a1b1cf7 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -236,9 +236,8 @@ if(ACL_FOUND)
   target_link_libraries(KF5KIOCore PRIVATE ${ACL_LIBS})
 endif()
 
-if(HAVE_LIBS_MOUNT_AND_BLKID)
-  # libmount links against blkid anyway
-  target_link_libraries(KF5KIOCore PRIVATE LibMount::LibMount Blkid::Blkid)
+if(HAVE_LIB_MOUNT)
+  target_link_libraries(KF5KIOCore PRIVATE LibMount::LibMount)
 endif()
 
 # this should be done by cmake, see bug 371721
diff --git a/src/core/config-kmountpoint.h.cmake b/src/core/config-kmountpoint.h.cmake
index f824d4042..3673eb141 100644
--- a/src/core/config-kmountpoint.h.cmake
+++ b/src/core/config-kmountpoint.h.cmake
@@ -1,7 +1,7 @@
 #cmakedefine01 HAVE_GETMNTINFO
 #cmakedefine01 GETMNTINFO_USES_STATVFS
 
-#cmakedefine01 HAVE_LIBS_MOUNT_AND_BLKID
+#cmakedefine01 HAVE_LIB_MOUNT
 
 #cmakedefine01 HAVE_SYS_MOUNT_H
 #cmakedefine01 HAVE_FSTAB_H
diff --git a/src/core/kmountpoint.cpp b/src/core/kmountpoint.cpp
index e2d32055c..f41cff5ee 100644
--- a/src/core/kmountpoint.cpp
+++ b/src/core/kmountpoint.cpp
@@ -44,7 +44,7 @@ static const Qt::CaseSensitivity cs = Qt::CaseSensitive;
 #endif
 
 // Linux
-#if HAVE_LIBS_MOUNT_AND_BLKID
+#if HAVE_LIB_MOUNT
 #include <libmount/libmount.h>
 #include <blkid/blkid.h>
 #endif
@@ -176,7 +176,7 @@ KMountPoint::List KMountPoint::possibleMountPoints(DetailsNeededFlags infoNeeded
 #ifdef Q_OS_WIN
     result = KMountPoint::currentMountPoints(infoNeeded);
 
-#elif HAVE_LIBS_MOUNT_AND_BLKID
+#elif HAVE_LIB_MOUNT
     if (struct libmnt_table *table = mnt_new_table()) {
         // By default parses "/etc/fstab"
         if (mnt_table_parse_fstab(table, nullptr) == 0) {
@@ -202,23 +202,13 @@ KMountPoint::List KMountPoint::possibleMountPoints(DetailsNeededFlags infoNeeded
                 // or some network mount
                 if (const char *source = mnt_fs_get_source(fs)) {
                     mp->d->m_mountedFrom = QFile::decodeName(source);
-                    if (mp->d->m_mountedFrom.startsWith(QLatin1String("UUID")) || mp->d->m_mountedFrom.startsWith(QLatin1String("LABEL"))) {
-                        // Use blkid to resolve UUID/LABEL to the device file
-                        if (char *blkSource = blkid_evaluate_spec(source, nullptr)) {
-                            mp->d->m_mountedFrom = QFile::decodeName(blkSource);
-                            free(blkSource);
-                            if ((infoNeeded & KMountPoint::NeedRealDeviceName) //
-                                && mp->d->m_mountedFrom.startsWith(QLatin1String("/dev/"))) {
-                                mp->d->m_device = mp->d->m_mountedFrom;
-                            }
-                        }
-                    }
                 }
 
                 if (infoNeeded & NeedMountOptions) {
                     mp->d->m_mountOptions = QFile::decodeName(mnt_fs_get_options(fs)).split(QLatin1Char(','));
                 }
 
+                mp->d->finalizePossibleMountPoint(infoNeeded);
                 result.append(mp);
             }
             mnt_free_iter(itr);
@@ -351,7 +341,7 @@ KMountPoint::List KMountPoint::currentMountPoints(DetailsNeededFlags infoNeeded)
         }
     }
 
-#elif HAVE_LIBS_MOUNT_AND_BLKID
+#elif HAVE_LIB_MOUNT
     if (struct libmnt_table *table = mnt_new_table()) {
         // By default, parses "/proc/self/mountinfo"
         if (mnt_table_parse_mtab(table, nullptr) == 0) {
-- 
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