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, 23 insertions, 0 deletions

diff --git a/samples/rust/Makefile b/samples/rust/Makefile
new file mode 100644
index 000000000..b986b681c
--- /dev/null
+++ b/samples/rust/Makefile
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0
+ccflags-y += -I$(src)				# needed for trace events
+
+obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
+obj-$(CONFIG_SAMPLE_RUST_MISC_DEVICE)		+= rust_misc_device.o
+obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_DEBUGFS)		+= rust_debugfs.o
+obj-$(CONFIG_SAMPLE_RUST_DEBUGFS_SCOPED)	+= rust_debugfs_scoped.o
+obj-$(CONFIG_SAMPLE_RUST_DMA)			+= rust_dma.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_I2C)		+= rust_driver_i2c.o
+obj-$(CONFIG_SAMPLE_RUST_I2C_CLIENT)		+= rust_i2c_client.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI)		+= rust_driver_pci.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM)	+= rust_driver_platform.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB)		+= rust_driver_usb.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX)		+= rust_driver_faux.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY)	+= rust_driver_auxiliary.o
+obj-$(CONFIG_SAMPLE_RUST_DRIVER_SERDEV)		+= rust_driver_serdev.o
+obj-$(CONFIG_SAMPLE_RUST_CONFIGFS)		+= rust_configfs.o
+obj-$(CONFIG_SAMPLE_RUST_SOC)			+= rust_soc.o
+
+rust_print-y := rust_print_main.o rust_print_events.o
+
+subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs