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Qu Wenruo c83d77eb0f btrfs: properly wait for writeback before buffered write 
[BUG]
Before commit e820dbeb6a ("btrfs: convert btrfs_buffered_write() to
use folios"), function prepare_one_folio() will always wait for folio
writeback to finish before returning the folio.

However commit e820dbeb6a ("btrfs: convert btrfs_buffered_write() to
use folios") changed to use FGP_STABLE to do the writeback wait, but
FGP_STABLE is calling folio_wait_stable(), which only calls
folio_wait_writeback() if the address space has AS_STABLE_WRITES, which
is not set for btrfs inodes.

This means we will not wait for the folio writeback at all.

[CAUSE]
The cause is FGP_STABLE is not waiting for writeback unconditionally, but
only for address spaces with AS_STABLE_WRITES, normally such flag is set
when the super block has SB_I_STABLE_WRITES flag.

Such super block flag is set when the block device has hardware digest
support or has internal checksum requirement.

I'd argue btrfs should set such super block due to its default data
checksum behavior, but it is not set yet, so this means FGP_STABLE flag
will have no effect at all.

(For NODATASUM inodes, we can skip the waiting in theory but that should
be an optimization in the future.)

This can lead to data checksum mismatch, as we can modify the folio
while it's still under writeback, this will make the contents differ
from the contents at submission and checksum calculation.

[FIX]
Instead of fully relying on FGP_STABLE, manually do the folio writeback
waiting, until we set the address space or super flag.

Fixes: e820dbeb6a ("btrfs: convert btrfs_buffered_write() to use folios")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-12-06 15:04:07 +01:00
arch 20 hotfixes, 14 of which are cc:stable. 2024-11-10 09:04:27 -08:00
block block-6.12-20241101 2024-11-01 13:41:55 -10:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes the following issues: 2024-10-16 08:42:54 -07:00
Documentation 20 hotfixes, 14 of which are cc:stable. 2024-11-10 09:04:27 -08:00
drivers A handful of Qualcomm clk driver fixes: 2024-11-10 14:16:28 -08:00
fs btrfs: properly wait for writeback before buffered write 2024-12-06 15:04:07 +01:00
include btrfs: add new ioctl to wait for cleaned subvolumes 2024-11-11 14:34:22 +01:00
init cfi: fix conditions for HAVE_CFI_ICALL_NORMALIZE_INTEGERS 2024-10-13 22:23:13 +02:00
io_uring io_uring/cmd: let cmds to know about dying task 2024-11-11 14:34:21 +01:00
ipc struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
kernel 20 hotfixes, 14 of which are cc:stable. 2024-11-10 09:04:27 -08:00
lib objpool: fix to make percpu slot allocation more robust 2024-11-07 14:14:58 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm filemap: Fix bounds checking in filemap_read() 2024-11-10 14:07:08 -08:00
net Including fixes from can and netfilter. 2024-11-07 11:07:57 -10:00
rust Driver core fix for 6.12-rc3 2024-10-13 09:10:52 -07:00
samples [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
scripts Kbuild fixes for v6.12 (2nd) 2024-11-03 08:29:02 -10:00
security KEYS: trusted: dcp: fix NULL dereference in AEAD crypto operation 2024-11-04 21:24:24 +02:00
sound ASoC: Fixes for v6.12 2024-11-08 09:25:33 +01:00
tools 20 hotfixes, 14 of which are cc:stable. 2024-11-10 09:04:27 -08:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt ARM64: 2024-10-21 11:22:04 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig
.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 Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.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 sound fixes for 6.12-rc7 2024-11-08 07:44:28 -10:00
Makefile Linux 6.12-rc7 2024-11-10 14:19:35 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.