scst_calc_block_shift() warns when the sector size is not a power of two but still returns its floor log2. When a backend returns a malformed READ CAPACITY response, scst_block_generic_dev_done() therefore changes the device geometry to an unrelated block size. For example, a block length of 809052976 produces 1 << 29 != 809052976 WARNING: ... at scst_calc_block_shift+0x9c/0xe0 [scst] and the device is switched to 536870912-byte blocks. Subsequent READ and WRITE commands then fail in PARSE until another READ CAPACITY restores the original block size. A zero block length is only logged, and the response is still returned to the initiator with GOOD status. Treat sector sizes below 512 bytes or not a power of two as invalid in scst_calc_block_shift() instead of warning. When a READ CAPACITY response reports a zero or invalid block length, keep the current geometry and complete the command with INTERNAL TARGET FAILURE sense, so that the initiator does not use the malformed capacity data.
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
