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Zhang Yi dd064d5101 ext4: introduce seq counter for the extent status entry
In the iomap_write_iter(), the iomap buffered write frame does not hold
any locks between querying the inode extent mapping info and performing
page cache writes. As a result, the extent mapping can be changed due to
concurrent I/O in flight. Similarly, in the iomap_writepage_map(), the
write-back process faces a similar problem: concurrent changes can
invalidate the extent mapping before the I/O is submitted.

Therefore, both of these processes must recheck the mapping info after
acquiring the folio lock. To address this, similar to XFS, we propose
introducing an extent sequence number to serve as a validity cookie for
the extent. After commit 24b7a2331f ("ext4: clairfy the rules for
modifying extents"), we can ensure the extent information should always
be processed through the extent status tree, and the extent status tree
is always uptodate under i_rwsem or invalidate_lock or folio lock, so
it's safe to introduce this sequence number. The sequence number will be
increased whenever the extent status tree changes, preparing for the
buffered write iomap conversion.

Besides, this mechanism is also applicable for the moving extents case.
In move_extent_per_page(), it also needs to reacquire data_sem and check
the mapping info again under the folio lock.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-ID: <20251013015128.499308-3-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-11-06 10:44:39 -05:00
arch Miscellaneous fixes: 2025-11-01 10:20:07 -07:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation sound fixes for 6.18-rc4 2025-10-31 07:29:09 -07:00
drivers spi: Fix for v6.18 2025-11-01 10:50:43 -07:00
fs ext4: introduce seq counter for the extent status entry 2025-11-06 10:44:39 -05:00
include ext4: introduce seq counter for the extent status entry 2025-11-06 10:44:39 -05:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring: fix buffer auto-commit for multishot uring_cmd 2025-10-23 19:41:31 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel bpf-fixes 2025-10-31 18:22:26 -07:00
lib Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab fixes for 6.18-rc3 2025-10-24 12:40:51 -07:00
net bpf-fixes 2025-10-31 18:22:26 -07:00
rust Driver core fixes for 6.18-rc3 2025-10-25 11:03:46 -07:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts kconfig/nconf: Initialize the default locale at startup 2025-11-01 00:23:22 -04:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ASoC: Fixes for v6.18 2025-10-30 13:08:08 +01:00
tools objtool: Fix skip_alt_group() for non-alternative STAC/CLAC 2025-11-01 07:43:20 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.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 MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap linux_kselftest-kunit-fixes-6.18-rc4 2025-10-30 19:11:27 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
Makefile Linux 6.18-rc4 2025-11-02 11:28:02 -08:00
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.