linux-ext4 - [PATCH v3 0/7] ext4: Add multi-fsblock atomic write support with bigalloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <cover.1746734745.git.ritesh.list@gmail.com>
Date: Fri,  9 May 2025 02:20:30 +0530
From: "Ritesh Harjani (IBM)" <ritesh.list@...il.com>
To: linux-ext4@...r.kernel.org
Cc: Theodore Ts'o <tytso@....edu>,
	Jan Kara <jack@...e.cz>,
	John Garry <john.g.garry@...cle.com>,
	djwong@...nel.org,
	Ojaswin Mujoo <ojaswin@...ux.ibm.com>,
	linux-fsdevel@...r.kernel.org,
	"Ritesh Harjani (IBM)" <ritesh.list@...il.com>
Subject: [PATCH v3 0/7] ext4: Add multi-fsblock atomic write support with bigalloc

This is v3 of multi-fsblock atomic write support using bigalloc. This has
started looking into much better shape now. The major chunk of the design
changes has been kept in Patch-4 & 5.

This series can now be carefully reviewed, as all the error handling related
code paths should be properly taken care of.

v2 -> v3:
=========
1. Improved error handling at several places.
2. Further fixed some worst case journal credits estimation.
3. Added better checks in the slow path allocation loop for atomic writes.

v3 testing so far:
===============
- This has survived "quick" & "auto" group testing with bigalloc on x86 and Power.
- We have also tested atomic write related tests using fio and some data integrity
  tests with sudden power off during writes on scsi_debug module.
  (Will clean up these tests and try to post them out soon!)

Appreciate any review comments / feedback!


v1 -> v2:
==========
1. Handled review comments from Ojaswin to optimize the ext4_map_block() calls
   in ext4_iomap_alloc().
2. Fixed the journal credits calculation for both:
	- during block allocation in ext4_iomap_alloc()
	- during dio completion in ->end_io callback.
   Earlier we were starting multiple txns in ->end_io callback for unwritten to
   written conversion. But since in case of atomic writes, we want a single jbd2
   txn, hence made the necessary changes there.
[v2]: https://lore.kernel.org/linux-ext4/cover.1745987268.git.ritesh.list@gmail.com/

Ritesh Harjani (IBM) (7):
  ext4: Document an edge case for overwrites
  ext4: Check if inode uses extents in ext4_inode_can_atomic_write()
  ext4: Make ext4_meta_trans_blocks() non-static for later use
  ext4: Add support for EXT4_GET_BLOCKS_QUERY_LEAF_BLOCKS
  ext4: Add multi-fsblock atomic write support with bigalloc
  ext4: Enable support for ext4 multi-fsblock atomic write using bigalloc
  ext4: Add atomic block write documentation

 .../filesystems/ext4/atomic_writes.rst        | 208 +++++++++++++
 Documentation/filesystems/ext4/overview.rst   |   1 +
 fs/ext4/ext4.h                                |  26 +-
 fs/ext4/extents.c                             |  99 ++++++
 fs/ext4/file.c                                |   7 +-
 fs/ext4/inode.c                               | 291 ++++++++++++++++--
 fs/ext4/super.c                               |   7 +-
 7 files changed, 614 insertions(+), 25 deletions(-)
 create mode 100644 Documentation/filesystems/ext4/atomic_writes.rst

--
2.49.0