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Qu Wenruo 1f3d56db69 btrfs: clear TAG_TOWRITE from buffer tree when submitting a tree block
[POSSIBLE BUG]
After commit 5e121ae687 ("btrfs: use buffer xarray for extent buffer
writeback operations"), we have a dedicated xarray for extent buffers,
and a lot of tags are migrated to that buffer tree, like
PAGECACHE_TAG_TOWRITE/DIRTY/WRITEBACK.

This frees us from the limits of page flags, but there is a new
asymmetric behavior, we call buffer_tree_tag_for_writeback() to set
PAGECACHE_TAG_TOWRITE for the involved ranges, but there is no one to
clear that tag.

Before that rework, we relied on the page cache tag which was cleared
when folio_start_writeback() was called.
Although this has its own problems (e.g. the first one calling
folio_start_writeback() will clear the tag for the whole page), it at
least cleared the tag.

But now our real tags are stored in the buffer tree, no one is really
clearing the PAGECACHE_TAG_TOWRITE tag now.

[FIX]
Thankfully this is not going to cause any real bug, but just some
inefficiency iterating the extent buffers.

As if we hit an extent buffer which is not dirty but still has the
PAGECACHE_TAG_TOWRITE tag, lock_extent_buffer_for_io() will skip it so
we won't writeback the extent buffer again.

To properly fix the inefficiency, just clear the PAGECACHE_TAG_TOWRITE
inside lock_extent_buffer_for_io().

There is no error path between lock_extent_buffer_for_io() and
write_one_eb(), so we're safe to clear the tag there.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-08-13 14:08:45 +02:00
arch A single fix for a GCC wreckage, which emits a KCSAN instrumentation call 2025-07-20 11:27:52 -07:00
block block-6.16-20250718 2025-07-18 12:16:13 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: wp512 - Use API partial block handling 2025-06-23 16:56:56 +08:00
Documentation Char/Misc/IIO fixes for 6.16-rc7 2025-07-20 09:03:41 -07:00
drivers i2c-for-6.16-rc7 2025-07-20 12:56:13 -07:00
fs btrfs: clear TAG_TOWRITE from buffer tree when submitting a tree block 2025-08-13 14:08:45 +02:00
include btrfs: defrag: add flag to force no-compression 2025-07-22 01:13:03 +02:00
init futex: Temporary disable FUTEX_PRIVATE_HASH 2025-07-01 15:02:05 +02:00
io_uring io_uring-6.16-20250718 2025-07-18 12:21:26 -07:00
ipc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kernel Tracing fixes for 6.16: 2025-07-20 13:03:31 -07:00
lib maple_tree: fix mt_destroy_walk() on root leaf node 2025-07-09 21:07:52 -07:00
LICENSES LICENSES: add CC0-1.0 license text 2025-05-21 14:54:17 +02:00
mm vfs-6.16-rc7.fixes 2025-07-19 08:47:59 -07:00
net bluetooth pull request for net: 2025-07-17 07:54:49 -07:00
rust Rust fixes for v6.16 (2nd) 2025-07-19 09:22:26 -07:00
samples samples/damon: fix damon sample mtier for start failure 2025-07-09 21:07:55 -07:00
scripts Rust fixes for v6.16 (2nd) 2025-07-19 09:22:26 -07:00
security selinux: change security_compute_sid to return the ssid or tsid on match 2025-06-19 16:13:16 -04:00
sound ASoC: Fixes for v6.16 2025-07-17 14:53:38 +02:00
tools A single fix for the futex selftest code to make 32-bit user space work 2025-07-20 11:22:05 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-06-24 12:20:17 -07:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore Python compiled bytecode 2025-04-24 10:12:46 -06:00
.mailmap MAINTAINERS: Update Kirill Shutemov's email address for TDX 2025-07-11 07:25:51 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -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 CREDITS: Add entry for Shannon Nelson 2025-06-21 07:34:28 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Char/Misc/IIO fixes for 6.16-rc7 2025-07-20 09:03:41 -07:00
Makefile Linux 6.16-rc7 2025-07-20 15:18:33 -07:00
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.