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QStorageInfo/Linux: avoid parsing /dev/disks/by-label for every entry

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Instead, create a (flat) map of the entries that we can seek on while
creating the list of mountedVolumes(). On my machine, that went down
from 14 times to 1.

Pick-to: 6.6
Change-Id: I9d43e5b91eb142d6945cfffd17875458541f28f9
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
This commit is contained in:
Thiago Macieira 2023-09-22 14:02:03 -07:00
parent 3e330a79ec
commit 4107e4d8ca
1 changed files with 40 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
src/corelib/io/qstorageinfo_linux.cpp
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@ -91,16 +91,41 @@ static inline quint64 retrieveDeviceId(const QByteArray &device, quint64 deviceI
return st.st_rdev; return st.st_rdev;
} }
static inline QString retrieveLabel(const QByteArray &device, quint64 deviceId) static QDirIterator devicesByLabel()
{ {
static const char pathDiskByLabel[] = "/dev/disk/by-label"; static const char pathDiskByLabel[] = "/dev/disk/by-label";
static constexpr auto LabelFileFilter =
QDir::AllEntries | QDir::System | QDir::Hidden | QDir::NoDotAndDotDot;
return QDirIterator(QLatin1StringView(pathDiskByLabel), LabelFileFilter);
}
static inline auto retrieveLabels()
{
struct Entry {
QString label;
quint64 deviceId;
};
QList<Entry> result;
QDirIterator it = devicesByLabel();
while (it.hasNext()) {
QFileInfo fileInfo = it.nextFileInfo();
quint64 deviceId = retrieveDeviceId(QFile::encodeName(fileInfo.filePath()));
if (!deviceId)
continue;
result.emplaceBack(Entry{ decodeFsEncString(fileInfo.fileName()), deviceId });
}
return result;
}
static inline QString retrieveLabel(const QByteArray &device, quint64 deviceId)
{
deviceId = retrieveDeviceId(device, deviceId); deviceId = retrieveDeviceId(device, deviceId);
if (!deviceId) if (!deviceId)
return QString(); return QString();
auto filter = QDir::AllEntries | QDir::System | QDir::Hidden | QDir::NoDotAndDotDot; QDirIterator it = devicesByLabel();
QDirIterator it(QLatin1StringView(pathDiskByLabel), filter);
while (it.hasNext()) { while (it.hasNext()) {
QFileInfo fileInfo = it.nextFileInfo(); QFileInfo fileInfo = it.nextFileInfo();
QString name = fileInfo.fileName(); QString name = fileInfo.fileName();
@ -206,6 +231,17 @@ QList<QStorageInfo> QStorageInfoPrivate::mountedVolumes()
if (infos.empty()) if (infos.empty())
return QList{root()}; return QList{root()};
auto labelForDevice = [labelMap = retrieveLabels()](const QByteArray &device, quint64 devid) {
devid = retrieveDeviceId(device, devid);
if (!devid)
return QString();
for (auto &[deviceLabel, deviceId] : labelMap) {
if (devid == deviceId)
return deviceLabel;
}
return QString();
};
QList<QStorageInfo> volumes; QList<QStorageInfo> volumes;
for (MountInfo &info : infos) { for (MountInfo &info : infos) {
QStorageInfoPrivate d(std::move(info)); QStorageInfoPrivate d(std::move(info));
@ -214,7 +250,7 @@ QList<QStorageInfo> QStorageInfoPrivate::mountedVolumes()
continue; continue;
if (info.stDev != deviceIdForPath(d.rootPath)) if (info.stDev != deviceIdForPath(d.rootPath))
continue; // probably something mounted over this mountpoint continue; // probably something mounted over this mountpoint
d.name = retrieveLabel(d.device, info.stDev); d.name = labelForDevice(d.device, info.stDev);
volumes.emplace_back(QStorageInfo(*new QStorageInfoPrivate(std::move(d)))); volumes.emplace_back(QStorageInfo(*new QStorageInfoPrivate(std::move(d))));
} }
return volumes; return volumes;