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Chao Yu 2f1657b07d f2fs: fix to detect gcing page in f2fs_is_cp_guaranteed() 
[ Upstream commit aa1be8dd64 ]

Jan Prusakowski reported a f2fs bug as below:

f2fs/007 will hang kernel during testing w/ below configs:

kernel 6.12.18 (from pixel-kernel/android16-6.12)
export MKFS_OPTIONS="-O encrypt -O extra_attr -O project_quota -O quota"
export F2FS_MOUNT_OPTIONS="test_dummy_encryption,discard,fsync_mode=nobarrier,reserve_root=32768,checkpoint_merge,atgc"

cat /proc/<umount_proc_id>/stack
f2fs_wait_on_all_pages+0xa3/0x130
do_checkpoint+0x40c/0x5d0
f2fs_write_checkpoint+0x258/0x550
kill_f2fs_super+0x14f/0x190
deactivate_locked_super+0x30/0xb0
cleanup_mnt+0xba/0x150
task_work_run+0x59/0xa0
syscall_exit_to_user_mode+0x12d/0x130
do_syscall_64+0x57/0x110
entry_SYSCALL_64_after_hwframe+0x76/0x7e

cat /sys/kernel/debug/f2fs/status

  - IO_W (CP: -256, Data:  256, Flush: (   0    0    1), Discard: (   0    0)) cmd:    0 undiscard:   0

CP IOs reference count becomes negative.

The root cause is:

After 4961acdd65 ("f2fs: fix to tag gcing flag on page during block
migration"), we will tag page w/ gcing flag for raw page of cluster
during its migration.

However, if the inode is both encrypted and compressed, during
ioc_decompress(), it will tag page w/ gcing flag, and it increase
F2FS_WB_DATA reference count:
- f2fs_write_multi_page
 - f2fs_write_raw_page
  - f2fs_write_single_page
   - do_write_page
    - f2fs_submit_page_write
     - WB_DATA_TYPE(bio_page, fio->compressed_page)
     : bio_page is encrypted, so mapping is NULL, and fio->compressed_page
       is NULL, it returns F2FS_WB_DATA
     - inc_page_count(.., F2FS_WB_DATA)

Then, during end_io(), it decrease F2FS_WB_CP_DATA reference count:
- f2fs_write_end_io
 - f2fs_compress_write_end_io
  - fscrypt_pagecache_folio
  : get raw page from encrypted page
  - WB_DATA_TYPE(&folio->page, false)
  : raw page has gcing flag, it returns F2FS_WB_CP_DATA
  - dec_page_count(.., F2FS_WB_CP_DATA)

In order to fix this issue, we need to detect gcing flag in raw page
in f2fs_is_cp_guaranteed().

Fixes: 4961acdd65 ("f2fs: fix to tag gcing flag on page during block migration")
Reported-by: Jan Prusakowski <jprusakowski@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-06-27 11:07:10 +01:00
arch arm64: Support ARM64_VA_BITS=52 when setting ARCH_MMAP_RND_BITS_MAX 2025-06-27 11:07:08 +01:00
block scsi: sd_zbc: block: Respect bio vector limits for REPORT ZONES buffer 2025-05-22 14:10:06 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2025-04-25 10:44:04 +02:00
crypto crypto: xts - Only add ecb if it is not already there 2025-06-27 11:07:06 +01:00
Documentation serial: mctrl_gpio: split disable_ms into sync and no_sync APIs 2025-06-04 14:40:13 +02:00
drivers iommu: Protect against overflow in iommu_pgsize() 2025-06-27 11:07:09 +01:00
fs f2fs: fix to detect gcing page in f2fs_is_cp_guaranteed() 2025-06-27 11:07:10 +01:00
include firmware: SDEI: Allow sdei initialization without ACPI_APEI_GHES 2025-06-27 11:07:08 +01:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:47:04 +02:00
io_uring io_uring: fix overflow resched cqe reordering 2025-06-04 14:40:20 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-14 19:54:06 +01:00
kernel PM: wakeup: Delete space in the end of string shown by pm_show_wakelocks() 2025-06-27 11:07:07 +01:00
lib crypto: lzo - Fix compression buffer overrun 2025-06-04 14:40:08 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/page_alloc.c: avoid infinite retries caused by cpuset race 2025-06-04 14:40:21 +02:00
net net: ncsi: Fix GCPS 64-bit member variables 2025-06-27 11:07:09 +01:00
rust scripts: generate_rust_analyzer: provide cfgs for core and alloc 2025-03-28 21:58:57 +01:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-06-04 14:40:02 +02:00
scripts kbuild: fix argument parsing in scripts/config 2025-06-04 14:40:06 +02:00
security smack: recognize ipv4 CIPSO w/o categories 2025-06-04 14:40:14 +02:00
sound ASoC: apple: mca: Constrain channels according to TDM mask 2025-06-27 11:07:07 +01:00
tools libbpf: Fix buffer overflow in bpf_object__init_prog 2025-06-27 11:07:09 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Fix a data race on last_boosted_vcpu in kvm_vcpu_on_spin() 2024-06-27 13:46:21 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.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: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Remove *.orig pattern from .gitignore 2024-10-17 15:21:15 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -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 Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
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 10:44:04 +02:00
Makefile Linux 6.1.141 2025-06-04 14:40:26 +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.