From cb38b5026a213f14ef0996f0057defb50969a62f Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Wed, 29 May 2024 10:14:58 -0300
Subject: [PATCH] QStorageInfo/Linux: reuse the file descriptor

We need it for the ioctl() to get the label and we already have it open.

Change-Id: If3345151ddf84c43a4f1fffd17d3f7f1312ca185
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit 24b1e52a1a46e9c7801a1bfffb963e56610872a7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/io/qstorageinfo_linux.cpp | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/src/corelib/io/qstorageinfo_linux.cpp b/src/corelib/io/qstorageinfo_linux.cpp
index 62efac667fd..111304bb860 100644
--- a/src/corelib/io/qstorageinfo_linux.cpp
+++ b/src/corelib/io/qstorageinfo_linux.cpp
@@ -165,10 +165,9 @@ static inline auto retrieveLabels()
     return result;
 }
 
-static std::optional<QString> retrieveLabelViaIoctl(const QString &path)
+static std::optional<QString> retrieveLabelViaIoctl(int fd)
 {
     // FS_IOC_GETFSLABEL was introduced in v4.18; previously it was btrfs-specific.
-    int fd = qt_safe_open(QFile::encodeName(path).constData(), QT_OPEN_RDONLY);
     if (fd < 0)
         return std::nullopt;
 
@@ -176,15 +175,14 @@ static std::optional<QString> retrieveLabelViaIoctl(const QString &path)
     // says) and the return code on success (0) does not indicate the length.
     char label[FSLABEL_MAX] = {};
     int r = ioctl(fd, FS_IOC_GETFSLABEL, &label);
-    close(fd);
     if (r < 0)
         return std::nullopt;
     return QString::fromUtf8(label);
 }
 
-static inline QString retrieveLabel(const QStorageInfoPrivate &d, quint64 deviceId)
+static inline QString retrieveLabel(const QStorageInfoPrivate &d, int fd, quint64 deviceId)
 {
-    if (auto label = retrieveLabelViaIoctl(d.rootPath))
+    if (auto label = retrieveLabelViaIoctl(fd))
         return *label;
 
     deviceId = retrieveDeviceId(d.device, deviceId);
@@ -290,7 +288,7 @@ void QStorageInfoPrivate::doStat()
     if (best) {
         auto stDev = best->stDev;
         setFromMountInfo(std::move(*best));
-        name = retrieveLabel(*this, stDev);
+        name = retrieveLabel(*this, fd, stDev);
     }
 }
 
@@ -301,11 +299,11 @@ QList<QStorageInfo> QStorageInfoPrivate::mountedVolumes()
         return QList{root()};
 
     std::optional<decltype(retrieveLabels())> labelMap;
-    auto labelForDevice = [&labelMap](const QStorageInfoPrivate &d, quint64 devid) {
+    auto labelForDevice = [&labelMap](const QStorageInfoPrivate &d, int fd, quint64 devid) {
         if (d.fileSystemType == "tmpfs")
             return QString();
 
-        if (auto label = retrieveLabelViaIoctl(d.rootPath))
+        if (auto label = retrieveLabelViaIoctl(fd))
             return *label;
 
         devid = retrieveDeviceId(d.device, devid);
@@ -346,7 +344,7 @@ QList<QStorageInfo> QStorageInfoPrivate::mountedVolumes()
         d.retrieveVolumeInfo();
         if (d.bytesTotal <= 0 && d.rootPath != u'/')
             continue;
-        d.name = labelForDevice(d, infoStDev);
+        d.name = labelForDevice(d, fd, infoStDev);
         volumes.emplace_back(QStorageInfo(*new QStorageInfoPrivate(std::move(d))));
     }
     return volumes;