netfs: zero the tail of a short DIO/unbuffered readgrafted

The buffered read collector zero-fills the tail of a short read that
stops below the inode's i_size (netfs_clear_unread()), so a read that
races an extending write still returns the expected number of bytes.
The non-buffered collector path does no such thing: it just records
how much was transferred.

Add the same zero-fill for the non-buffered case, gated on
NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short
result from it is known to be safe to treat as a hole, as opposed to
NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of
the file and should be reported short as-is. Only CLEAR_TAIL should
zero-fill here; a real EOF must stay a real short read.

No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest,
so this is inert on its own -- a following change teaches cifs to set
it in the one case that needs it.

Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org

1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/firewire/Kconfig b/drivers/firewire/Kconfig
new file mode 100644
index 000000000..b5abe00ac
--- /dev/null
+++ b/drivers/firewire/Kconfig
@@ -0,0 +1,177 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "IEEE 1394 (FireWire) support"
+	depends on PCI || COMPILE_TEST
+	# firewire-core does not depend on PCI but is
+	# not useful without PCI controller driver
+
+config FIREWIRE
+	tristate "FireWire driver stack"
+	select CRC_ITU_T
+	help
+	  This is the new-generation IEEE 1394 (FireWire) driver stack
+	  a.k.a. Juju, a new implementation designed for robustness and
+	  simplicity.
+	  See http://ieee1394.docs.kernel.org/en/latest/migration.html
+	  for information about migration from the older Linux 1394 stack
+	  to the new driver stack.
+
+	  To compile this driver as a module, say M here: the module will be
+	  called firewire-core.
+
+config FIREWIRE_KUNIT_UAPI_TEST
+	tristate "KUnit tests for layout of structure in UAPI" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests whether structures exposed to user
+	  space have expected layout.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_KUNIT_DEVICE_ATTRIBUTE_TEST
+	tristate "KUnit tests for device attributes" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests for device attribute for node and
+	  unit.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_KUNIT_PACKET_SERDES_TEST
+	tristate "KUnit tests for packet serialization/deserialization" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests for packet serialization and
+	  deserialization.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_KUNIT_SELF_ID_SEQUENCE_HELPER_TEST
+	tristate "KUnit tests for helpers of self ID sequence" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests for helpers of self ID sequence.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_KUNIT_NODE_TREE_TEST
+	tristate "KUnit tests for node tree" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests for node tree.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_OHCI
+	tristate "OHCI-1394 controllers"
+	depends on PCI && FIREWIRE
+	help
+	  Enable this driver if you have a FireWire controller based
+	  on the OHCI specification.  For all practical purposes, this
+	  is the only chipset in use, so say Y here.
+
+	  To compile this driver as a module, say M here:  The module will be
+	  called firewire-ohci.
+
+config FIREWIRE_KUNIT_OHCI_SERDES_TEST
+	tristate "KUnit tests for serialization/deserialization of data in buffers/registers" if !KUNIT_ALL_TESTS
+	depends on FIREWIRE && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the KUnit tests to check serialization and deserialization
+	  of data in buffers and registers defined in 1394 OHCI specification.
+
+	  KUnit tests run during boot and output the results to the debug
+	  log in TAP format (https://testanything.org/). Only useful for
+	  kernel devs running KUnit test harness and are not for inclusion
+	  into a production build.
+
+	  For more information on KUnit and unit tests in general, refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+config FIREWIRE_SBP2
+	tristate "Storage devices (SBP-2 protocol)"
+	depends on FIREWIRE && SCSI
+	help
+	  This option enables you to use SBP-2 devices connected to a
+	  FireWire bus.  SBP-2 devices include storage devices like
+	  harddisks and DVD drives, also some other FireWire devices
+	  like scanners.
+
+	  To compile this driver as a module, say M here:  The module will be
+	  called firewire-sbp2.
+
+	  You should also enable support for disks, CD-ROMs, etc. in the SCSI
+	  configuration section.
+
+config FIREWIRE_NET
+	tristate "IP networking over 1394"
+	depends on FIREWIRE && INET
+	help
+	  This enables IPv4/IPv6 over IEEE 1394, providing IP connectivity
+	  with other implementations of RFC 2734/3146 as found on several
+	  operating systems.  Multicast support is currently limited.
+
+	  To compile this driver as a module, say M here:  The module will be
+	  called firewire-net.
+
+config FIREWIRE_NOSY
+	tristate "Nosy - a FireWire traffic sniffer for PCILynx cards"
+	depends on PCI
+	help
+	  Nosy is an IEEE 1394 packet sniffer that is used for protocol
+	  analysis and in development of IEEE 1394 drivers, applications,
+	  or firmwares.
+
+	  This driver lets you use a Texas Instruments PCILynx 1394 to PCI
+	  link layer controller TSB12LV21/A/B as a low-budget bus analyzer.
+	  PCILynx is a nowadays very rare IEEE 1394 controller which is
+	  not OHCI 1394 compliant.
+
+	  The following cards are known to be based on PCILynx or PCILynx-2:
+	  IOI IOI-1394TT (PCI card), Unibrain Fireboard 400 PCI Lynx-2
+	  (PCI card), Newer Technology FireWire 2 Go (CardBus card),
+	  Apple Power Mac G3 blue & white and G4 with PCI graphics
+	  (onboard controller).
+
+	  To compile this driver as a module, say M here:  The module will be
+	  called nosy.  Source code of a userspace interface to nosy, called
+	  nosy-dump, can be found in tools/firewire/ of the kernel sources.
+
+	  If unsure, say N.
+
+endmenu