There are two advantages:
* Direct I/O allows to avoid the write-back cache, so it reduces affects
to other processes in the system.
* Async I/O allows to handle a few commands concurrently.
DIO + AIO shows a better perfomance for random write operations:
Mode: O_DSYNC Async: 1
$ ./fio --bs=4K --direct=1 --rw=randwrite --ioengine=libaio --iodepth=64 --name=/dev/sda --runtime=20 --numjobs=2
WRITE: bw=45.9MiB/s (48.1MB/s), 21.9MiB/s-23.0MiB/s (22.0MB/s-25.2MB/s), io=919MiB (963MB), run=20002-20020msec
Mode: O_DSYNC Async: 0
$ ./fio --bs=4K --direct=1 --rw=randwrite --ioengine=libaio --iodepth=64 --name=/dev/sdb --runtime=20 --numjobs=2
WRITE: bw=1607KiB/s (1645kB/s), 802KiB/s-805KiB/s (821kB/s-824kB/s), io=31.8MiB (33.4MB), run=20280-20295msec
Known issue:
DIF (PI) emulation doesn't work when a target uses async I/O, because
DIF metadata is saved in a separate file, and it is another non-trivial
task how to synchronize writing in two files, so that a following read
operation always returns a consisten metadata for a specified block.
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Tested-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove superfluous #include directives from the include/target/*.h
files. Add missing #include directives to other *.h and *.c files.
Use forward declarations for structures where possible. This
change reduces the build time for make M=drivers/target on my
laptop from 27.1s to 18.7s or by about 30%.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bryant G. Ly <bryantly@linux.vnet.ibm.com>
The reason this bounce buffer exists is to allow code
reuse between rd_mcp and fileio in DIF mode. But the fact is,
that this bounce is really not needed at all, we can simply call
sbc_dif_verify on cmd->t_prot_sg and use it for file IO.
This also removes fd_do_prot_rw as fd_do_rw was generalised
to receive file pointer, block size (8 bytes for DIF data) and
total data length.
(Fix apply breakage from commit c836777 - nab)
Tested-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Pull SCSI target updates from Nicholas Bellinger:
"The highlights this round include:
- add support for SCSI Referrals (Hannes)
- add support for T10 DIF into target core (nab + mkp)
- add support for T10 DIF emulation in FILEIO + RAMDISK backends (Sagi + nab)
- add support for T10 DIF -> bio_integrity passthrough in IBLOCK backend (nab)
- prep changes to iser-target for >= v3.15 T10 DIF support (Sagi)
- add support for qla2xxx N_Port ID Virtualization - NPIV (Saurav + Quinn)
- allow percpu_ida_alloc() to receive task state bitmask (Kent)
- fix >= v3.12 iscsi-target session reset hung task regression (nab)
- fix >= v3.13 percpu_ref se_lun->lun_ref_active race (nab)
- fix a long-standing network portal creation race (Andy)"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (51 commits)
target: Fix percpu_ref_put race in transport_lun_remove_cmd
target/iscsi: Fix network portal creation race
target: Report bad sector in sense data for DIF errors
iscsi-target: Convert gfp_t parameter to task state bitmask
iscsi-target: Fix connection reset hang with percpu_ida_alloc
percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask
iscsi-target: Pre-allocate more tags to avoid ack starvation
qla2xxx: Configure NPIV fc_vport via tcm_qla2xxx_npiv_make_lport
qla2xxx: Enhancements to enable NPIV support for QLOGIC ISPs with TCM/LIO.
qla2xxx: Fix scsi_host leak on qlt_lport_register callback failure
IB/isert: pass scatterlist instead of cmd to fast_reg_mr routine
IB/isert: Move fastreg descriptor creation to a function
IB/isert: Avoid frwr notation, user fastreg
IB/isert: seperate connection protection domains and dma MRs
tcm_loop: Enable DIF/DIX modes in SCSI host LLD
target/rd: Add DIF protection into rd_execute_rw
target/rd: Add support for protection SGL setup + release
target/rd: Refactor rd_build_device_space + rd_release_device_space
target/file: Add DIF protection support to fd_execute_rw
target/file: Add DIF protection init/format support
...
This patch adds support for DIF protection into fd_execute_rw() code
for WRITE/READ I/O using sbc_dif_verify_[write,read]() logic.
It adds fd_do_prot_rw() for handling interface with FILEIO PI, and
uses a locally allocated fd_prot->prot_buf + fd_prot->prot_sg for
interacting with SBC DIF verify emulation code.
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch adds support for DIF protection init/format support into
the FILEIO backend.
It involves using a seperate $FILE.protection for storing PI that is
opened via fd_init_prot() using the common pi_prot_type attribute.
The actual formatting of the protection is done via fd_format_prot()
using the common pi_prot_format attribute, that will populate the
initial PI data based upon the currently configured pi_prot_type.
Based on original FILEIO code from Sagi.
v1 changes:
- Fix sparse warnings in fd_init_format_buf (Fengguang)
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch allows FILEIO to update hw_max_sectors based on the current
max_bytes_per_io. This is required because vfs_[writev,readv]() can accept
a maximum of 2048 iovecs per call, so the enforced hw_max_sectors really
needs to be calculated based on block_size.
This addresses a >= v3.5 bug where block_size=512 was rejecting > 1M
sized I/O requests, because FD_MAX_SECTORS was hardcoded to 2048 for
the block_size=4096 case.
(v2: Use max_bytes_per_io instead of ->update_hw_max_sectors)
Reported-by: Henrik Goldman <hg@x-formation.com>
Cc: <stable@vger.kernel.org> #3.5+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch bumps the default FILEIO backend FD_MAX_SECTORS value from
1024 -> 2048 in order to allow block_size=512 to handle 1M sized I/Os.
The current default rejects I/Os larger than 512K in sbc_parse_cdb():
[12015.915146] SCSI OP 2ah with too big sectors 1347 exceeds backend
hw_max_sectors: 1024
[12015.977744] SCSI OP 2ah with too big sectors 2048 exceeds backend
hw_max_sectors: 1024
This issue is present in >= v3.5 based kernels, introduced after the
removal of se_task logic.
Reported-by: Viljami Ilola <azmulx@netikka.fi>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Simplify the code a lot by killing the superflous struct se_subsystem_dev.
Instead se_device is allocated early on by the backend driver, which allocates
it as part of its own per-device structure, borrowing the scheme that is for
example used for inode allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch re-adds the ability to optionally run in buffered FILEIO mode
(eg: w/o O_DSYNC) for device backends in order to once again use the
Linux buffered cache as a write-back storage mechanism.
This logic was originally dropped with mainline v3.5-rc commit:
commit a4dff3043c
Author: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Wed May 30 16:25:41 2012 -0700
target/file: Use O_DSYNC by default for FILEIO backends
This difference with this patch is that fd_create_virtdevice() now
forces the explicit setting of emulate_write_cache=1 when buffered FILEIO
operation has been enabled.
(v2: Switch to FDBD_HAS_BUFFERED_IO_WCE + add more detailed
comment as requested by hch)
Reported-by: Ferry <iscsitmp@bananateam.nl>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Convert to use O_DSYNC for all cases at FILEIO backend creation time to
avoid the extra syncing of pure timestamp updates with legacy O_SYNC during
default operation as recommended by hch. Continue to do this independently of
Write Cache Enable (WCE) bit, as WCE=0 is currently the default for all backend
devices and enabled by user on per device basis via attrib/emulate_write_cache.
This patch drops the now unnecessary fd_buffered_io= token usage that was
originally signalling when to explictly disable O_SYNC at backend creation
time for buffered I/O operation. This can end up being dangerous for a number
of reasons during physical node failure, so go ahead and drop this option
for now when O_DSYNC is used as the default.
Also allow explict FUA WRITEs -> vfs_fsync_range() call to function in
fd_execute_cmd() independently of WCE bit setting.
Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
We can use struct se_cmd for everything it did. Make sure to pass the S/G
list and data direction to the execution function to ease adding back BIDI
support later on.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
The most commonly used file, iblock and rd backends have no use for
a per-task CDB and thus don't need a method to copy it into their
otherwise unused CDB fields.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch contains the squashed version of forth round series cleanups
from Andy and Christoph following the post heavy lifting in the preceeding:
'Eliminate usage of struct se_mem' and 'Make all control CDBs scatter-gather'
changes. This also includes a conversion of target core and the v3.0
mainline fabric modules (loopback and tcm_fc) to use pr_debug and the
CONFIG_DYNAMIC_DEBUG infrastructure!
These have been squashed into this third and final round for v3.1.
target: Remove ifdeffed code in t_g_process_write
target: Remove direct ramdisk code
target: Rename task_sg_num to task_sg_nents
target: Remove custom debug macros for pr_debug. Use pr_err().
target: Remove custom debug macros in mainline fabrics
target: Set WSNZ=1 in block limits VPD. Abort if WRITE_SAME sectors = 0
target: Remove transport do_se_mem_map callback
target: Further simplify transport_free_pages
target: Redo task allocation return value handling
target: Remove extra parentheses
target: change alloc_task call to take *cdb, not *cmd
(nab: Fix bogus struct file assignments in fd_do_readv and fd_do_writev)
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch contains the squashed version of a number of cleanups and
minor fixes from Andy's initial series (round 1) for target core this
past spring. The condensed log looks like:
target: use errno values instead of returning -1 for everything
target: Rename transport_calc_sg_num to transport_init_task_sg
target: Fix leak in error path in transport_init_task_sg
target/pscsi: Remove pscsi_get_sh() usage
target: Make two runtime checks into WARN_ONs
target: Remove hba queue depth and convert to spin_lock_irq usage
target: dev->dev_status_queue_obj is unused
target: Make struct se_queue_req.cmd type struct se_cmd *
target: Remove __transport_get_qr_from_queue()
target: Rename se_dev->g_se_dev_list to se_dev_node
target: Remove struct se_global
target: Simplify scsi mib index table code
target: Make dev_queue_obj a member of se_device instead of a pointer
target: remove extraneous returns at end of void functions
target: Ensure transport_dump_vpd_ident_type returns null-terminated str
target: Function pointers don't need to use '&' to be assigned
target: Fix comment in __transport_execute_tasks()
target: Misc style cleanups
target: rename struct pr_reservation_template to pr_reservation
target: Remove #defines that just perform indirection
target: Inline transport_get_task_from_execute_queue()
target: Minor header comment fixes
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
LIO target is a full featured in-kernel target framework with the
following feature set:
High-performance, non-blocking, multithreaded architecture with SIMD
support.
Advanced SCSI feature set:
* Persistent Reservations (PRs)
* Asymmetric Logical Unit Assignment (ALUA)
* Protocol and intra-nexus multiplexing, load-balancing and failover (MC/S)
* Full Error Recovery (ERL=0,1,2)
* Active/active task migration and session continuation (ERL=2)
* Thin LUN provisioning (UNMAP and WRITE_SAMExx)
Multiprotocol target plugins
Storage media independence:
* Virtualization of all storage media; transparent mapping of IO to LUNs
* No hard limits on number of LUNs per Target; maximum LUN size ~750 TB
* Backstores: SATA, SAS, SCSI, BluRay, DVD, FLASH, USB, ramdisk, etc.
Standards compliance:
* Full compliance with IETF (RFC 3720)
* Full implementation of SPC-4 PRs and ALUA
Significant code cleanups done by Christoph Hellwig.
[jejb: fix up for new block bdev exclusive interface. Minor fixes from
Randy Dunlap and Dan Carpenter.]
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Andrei Vagin
Greg Kroah-Hartman
Bart Van Assche
Sagi Grimberg
Linus Torvalds
Nicholas Bellinger
Christoph Hellwig
Andy Grover