From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read 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 Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- Documentation/admin-guide/sysctl/abi.rst | 34 ++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 Documentation/admin-guide/sysctl/abi.rst (limited to 'Documentation/admin-guide/sysctl/abi.rst') diff --git a/Documentation/admin-guide/sysctl/abi.rst b/Documentation/admin-guide/sysctl/abi.rst new file mode 100644 index 000000000..4e6db0a2a --- /dev/null +++ b/Documentation/admin-guide/sysctl/abi.rst @@ -0,0 +1,34 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +================================ +Documentation for /proc/sys/abi/ +================================ + +.. See scripts/check-sysctl-docs to keep this up to date: +.. scripts/check-sysctl-docs -vtable="abi" \ +.. Documentation/admin-guide/sysctl/abi.rst \ +.. $(git grep -l register_sysctl_) + +Copyright (c) 2020, Stephen Kitt + +For general info, see Documentation/admin-guide/sysctl/index.rst. + +------------------------------------------------------------------------------ + +The files in ``/proc/sys/abi`` can be used to see and modify +ABI-related settings. + +Currently, these files might (depending on your configuration) +show up in ``/proc/sys/kernel``: + +.. contents:: :local: + +vsyscall32 (x86) +================ + +Determines whether the kernels maps a vDSO page into 32-bit processes; +can be set to 1 to enable, or 0 to disable. Defaults to enabled if +``CONFIG_COMPAT_VDSO`` is set, disabled otherwise. + +This controls the same setting as the ``vdso32`` kernel boot +parameter. -- cgit v1.3.1