Gleb Chesnokov
6d4751538b
Writing and waiting for dirty pages does not guarantee that the data can
be recovered after a crash. For example, a write into a sparse backing
file can also require an allocation or journal update, and the backing
device can still hold the data in a volatile write cache. A successful
FUA or SYNCHRONIZE CACHE must not acknowledge only page writeback.
The 2009 Linux 2.6.32 port replaced sync_page_range(), which also performed
metadata synchronization, with filemap_write_and_wait_range(). The
alternative generic_write_sync() was left disabled; it would also be
insufficient for an ordinary write-back file because it checks O_DSYNC.
Use vfs_fsync_range() with datasync enabled to let the filesystem persist
the data and the metadata needed to retrieve it, including any required
backend flush. Keep the existing range, DIF-tag handling and SCSI error
reporting. The API is available in all kernels in the nightly matrix.
Remove the unused writeback test boundary and its stub. The private file
operations now record filesystem synchronization directly, so a missing
fsync still fails the existing flush-count assertions.
Fixes: 2b5833d90e ("Update for 2.6.32 + fix context of vdisk_t10_dev_id_rwlock")
Link: https://github.com/SCST-project/scst/issues/395
Overview
This is the source code repository of the SCST project. SCST is a collection of Linux kernel drivers that implement SCSI target functionality. The SCST project includes:
- The SCST core in the scst/ subdirectory.
- A tool for loading, saving and modifying the SCST configuration in directory scstadmin/.
- Several SCSI target drivers in the directories iscsi-scst/, qla2x00t-32gbit/, qla2x00t/, srpt/, scst_local/ and fcst/.
- User space programs in the usr/ subdirectory, e.g. fileio_tgt.
- Various documentation in the doc/ subdirectory.
Documentation
- Building and installing SCST.
- Build options: Clang, cross-compilation, and kernel module signing.
- Configuration and administration: targets, devices,
LUNs, and
/etc/scst.conf. - Core and device handlers: operating modes, module parameters, and sysfs configuration.
- Target drivers: iSCSI, iSER, QLogic Fibre Channel, SRP, FCoE, and local loopback.
- Performance tuning.
- Clustered persistent reservations: synchronization through DLM.
- T10 protection information: data integrity modes and configuration.
- Developer references: architecture and userspace handler interface (SGML sources), and sysfs interface rules.
- Contributing: code style, commit conventions, local checks, and guides to KUnit and component testing.
Current master packages
Prebuilt x86_64 packages from the latest successfully published master
build are available in the rolling
master-rpm prerelease.
These are development snapshots, not SCST releases.
The snapshot contains RPM bundles for selected Rocky Linux and Oracle Linux
UEK kernels. It also contains Ubuntu LTS bundles with scst-dkms, scstadmin
and iscsi-scst binary packages and their Debian source package files. Exact
distribution releases and RPM kernel versions are included in the asset names.
Every .tar.gz bundle has a matching .sha256 file. The complete snapshot is
replaced after each successful package workflow for the current master
commit.
QLogic target driver
Two QLogic target drivers are included in the SCST project.
The default driver is located in the qla2x00t-32gbit directory. It is the newer one.
May anyone wish to switch back to the older driver that only supported up to
16 Gb/s adapters, it is located in qla2x00t directory. To make use of the
older driver build scst with environment variable QLA_32GBIT=no set.
Vladislav Bolkhovitin vst@vlnb.net, http://scst.sourceforge.net
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