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Zhang Yi 23fe8aa8cc ext4: remove writable userspace mappings before truncating page cache 
[ Upstream commit 17207d0bb2 ]

When zeroing a range of folios on the filesystem which block size is
less than the page size, the file's mapped blocks within one page will
be marked as unwritten, we should remove writable userspace mappings to
ensure that ext4_page_mkwrite() can be called during subsequent write
access to these partial folios. Otherwise, data written by subsequent
mmap writes may not be saved to disk.

 $mkfs.ext4 -b 1024 /dev/vdb
 $mount /dev/vdb /mnt
 $xfs_io -t -f -c "pwrite -S 0x58 0 4096" -c "mmap -rw 0 4096" \
               -c "mwrite -S 0x5a 2048 2048" -c "fzero 2048 2048" \
               -c "mwrite -S 0x59 2048 2048" -c "close" /mnt/foo

 $od -Ax -t x1z /mnt/foo
 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
 *
 000800 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59
 *
 001000

 $umount /mnt && mount /dev/vdb /mnt
 $od -Ax -t x1z /mnt/foo
 000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
 *
 000800 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 *
 001000

Fix this by introducing ext4_truncate_page_cache_block_range() to remove
writable userspace mappings when truncating a partial folio range.
Additionally, move the journal data mode-specific handlers and
truncate_pagecache_range() into this function, allowing it to serve as a
common helper that correctly manages the page cache in preparation for
block range manipulations.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/20241220011637.1157197-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-06-04 14:42:12 +02:00
arch arch/powerpc/perf: Check the instruction type before creating sample with perf_mem_data_src 2025-06-04 14:42:11 +02:00
block scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer 2025-05-22 14:12:22 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2025-04-25 10:45:58 +02:00
crypto crypto: skcipher - Zap type in crypto_alloc_sync_skcipher 2025-06-04 14:42:06 +02:00
Documentation serial: mctrl_gpio: split disable_ms into sync and no_sync APIs 2025-06-04 14:42:07 +02:00
drivers leds: trigger: netdev: Configure LED blink interval for HW offload 2025-06-04 14:42:12 +02:00
fs ext4: remove writable userspace mappings before truncating page cache 2025-06-04 14:42:12 +02:00
include r8152: add vendor/device ID pair for Dell Alienware AW1022z 2025-06-04 14:42:11 +02:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:50:57 +02:00
io_uring io_uring: ensure deferred completions are posted for multishot 2025-05-18 08:24:10 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-09 10:32:54 +01:00
kernel sched: Reduce the default slice to avoid tasks getting an extra tick 2025-06-04 14:42:09 +02:00
lib crypto: lzo - Fix compression buffer overrun 2025-06-04 14:42:01 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm hwpoison, memory_hotplug: lock folio before unmap hwpoisoned folio 2025-05-22 14:12:25 +02:00
net ip: fib_rules: Fetch net from fib_rule in fib[46]_rule_configure(). 2025-06-04 14:42:11 +02:00
rust rust: lockdep: Remove support for dynamically allocated LockClassKeys 2025-03-22 12:50:50 -07:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-06-04 14:41:53 +02:00
scripts kbuild: fix argument parsing in scripts/config 2025-06-04 14:41:58 +02:00
security smack: Revert "smackfs: Added check catlen" 2025-06-04 14:42:09 +02:00
sound ASoC: soc-dai: check return value at snd_soc_dai_set_tdm_slot() 2025-06-04 14:42:08 +02:00
tools kunit: tool: Use qboot on QEMU x86_64 2025-06-04 14:42:09 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 12:58:38 +01:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 sign-file,extract-cert: move common SSL helper functions to a header 2025-04-25 10:45:57 +02:00
Makefile Linux 6.6.92 2025-05-22 14:12:26 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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 Restructured Text 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.