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Zhang Yi d17857b4fb ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1
commit 1bf6974822 upstream.

When allocating initialized blocks from a large unwritten extent, or
when splitting an unwritten extent during end I/O and converting it to
initialized, there is currently a potential issue of stale data if the
extent needs to be split in the middle.

       0  A      B  N
       [UUUUUUUUUUUU]    U: unwritten extent
       [--DDDDDDDD--]    D: valid data
          |<-  ->| ----> this range needs to be initialized

ext4_split_extent() first try to split this extent at B with
EXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but
ext4_split_extent_at() failed to split this extent due to temporary lack
of space. It zeroout B to N and mark the entire extent from 0 to N
as written.

       0  A      B  N
       [WWWWWWWWWWWW]    W: written extent
       [SSDDDDDDDDZZ]    Z: zeroed, S: stale data

ext4_split_extent() then try to split this extent at A with
EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left
a stale written extent from 0 to A.

       0  A      B   N
       [WW|WWWWWWWWWW]
       [SS|DDDDDDDDZZ]

Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at()
when splitting at B, don't convert the entire extent to written and left
it as unwritten after zeroing out B to N. The remaining work is just
like the standard two-part split. ext4_split_extent() will pass the
EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the
second time, allowing it to properly handle the split. If the split is
successful, it will keep extent from 0 to A as unwritten.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Cc: stable@kernel.org
Message-ID: <20251129103247.686136-3-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-03-04 07:20:46 -05:00
arch MIPS: Work around LLVM bug when gp is used as global register variable 2026-03-04 07:20:46 -05:00
block block: add a bio_add_virt_nofail helper 2026-03-04 07:19:26 -05:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:28:39 +01:00
Documentation Documentation: tracing: Add PCI tracepoint documentation 2026-03-04 07:19:59 -05:00
drivers drm/amd/display: Use same max plane scaling limits for all 64 bpp formats 2026-03-04 07:20:46 -05:00
fs ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 2026-03-04 07:20:46 -05:00
include net/mlx5: Fix multiport device check over light SFs 2026-03-04 07:20:39 -05:00
init init: handle bootloader identifier in kernel parameters 2025-10-19 16:33:50 +02:00
io_uring io_uring/cancel: de-unionize file and user_data in struct io_cancel_data 2026-03-04 07:20:34 -05:00
ipc ipc: don't audit capability check in ipc_permissions() 2026-03-04 07:20:07 -05:00
kernel tracing: Remove duplicate ENABLE_EVENT_STR and DISABLE_EVENT_STR macros 2026-03-04 07:20:25 -05:00
lib objpool: fix the overestimation of object pooling metadata size 2026-03-04 07:20:35 -05:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/hugetlb: fix excessive IPI broadcasts when unsharing PMD tables using mmu_gather 2026-02-19 16:29:55 +01:00
net icmp: prevent possible overflow in icmp_global_allow() 2026-03-04 07:20:39 -05:00
rust rust: rbtree: fix documentation typo in CursorMut peek_next method 2026-02-06 16:55:44 +01:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:14:50 +01:00
scripts scripts: generate_rust_analyzer: Add compiler_builtins -> core dep 2026-02-06 16:55:47 +01:00
security apparmor: fix aa_label to return state from compount and component match 2026-03-04 07:20:41 -05:00
sound ASoC: rockchip: i2s-tdm: Use param rate if not provided by set_sysclk 2026-03-04 07:20:46 -05:00
tools bpftool: Fix truncated netlink dumps 2026-03-04 07:20:38 -05:00
usr kbuild: uapi: Strip comments before size type check 2025-11-13 15:34:35 -05:00
virt KVM: Don't clobber irqfd routing type when deassigning irqfd 2026-02-11 13:40:17 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS gpiolib-acpi: Update file references in the Documentation and MAINTAINERS 2026-02-11 13:40:29 +01:00
Makefile kbuild: Add objtool to top-level clean target 2026-03-04 07:20:35 -05:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.