Pull ext4 updates from Ted Ts'o:
 "A lot of miscellaneous ext4 bug fixes and cleanups this cycle, most
  notably in the journaling code, bufered I/O, and compiler warning
  cleanups"

* tag 'ext4_for_linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits)
  jbd2: Fix comment describing journal_init_common()
  ext4: prevent an infinite loop in the lazyinit thread
  ext4: use struct_size() to improve ext4_htree_store_dirent()
  ext4: annotate struct fname with __counted_by()
  jbd2: avoid dozens of -Wflex-array-member-not-at-end warnings
  ext4: use str_yes_no() helper function
  ext4: prevent delalloc to nodelalloc on remount
  jbd2: make b_frozen_data allocation always succeed
  ext4: cleanup variable name in ext4_fc_del()
  ext4: use string choices helpers
  jbd2: remove the 'success' parameter from the jbd2_do_replay() function
  jbd2: remove useless 'block_error' variable
  jbd2: factor out jbd2_do_replay()
  jbd2: refactor JBD2_COMMIT_BLOCK process in do_one_pass()
  jbd2: unified release of buffer_head in do_one_pass()
  jbd2: remove redundant judgments for check v1 checksum
  ext4: use ERR_CAST to return an error-valued pointer
  mm: zero range of eof folio exposed by inode size extension
  ext4: partial zero eof block on unaligned inode size extension
  ext4: disambiguate the return value of ext4_dio_write_end_io()
  ...

Pull vfs untorn write support from Christian Brauner:
 "An atomic write is a write issed with torn-write protection. This
  means for a power failure or any hardware failure all or none of the
  data from the write will be stored, never a mix of old and new data.

  This work is already supported for block devices. If a block device is
  opened with O_DIRECT and the block device supports atomic write, then
  FMODE_CAN_ATOMIC_WRITE is added to the file of the opened block
  device.

  This contains the work to expand atomic write support to filesystems,
  specifically ext4 and XFS. Currently, only support for writing exactly
  one filesystem block atomically is added.

  Since it's now possible to have filesystem block size > page size for
  XFS, it's possible to write 4K+ blocks atomically on x86"

* tag 'vfs-6.13.untorn.writes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: drop an obsolete comment in iomap_dio_bio_iter
  ext4: Do not fallback to buffered-io for DIO atomic write
  ext4: Support setting FMODE_CAN_ATOMIC_WRITE
  ext4: Check for atomic writes support in write iter
  ext4: Add statx support for atomic writes
  xfs: Support setting FMODE_CAN_ATOMIC_WRITE
  xfs: Validate atomic writes
  xfs: Support atomic write for statx
  fs: iomap: Atomic write support
  fs: Export generic_atomic_write_valid()
  block: Add bdev atomic write limits helpers
  fs/block: Check for IOCB_DIRECT in generic_atomic_write_valid()
  block/fs: Pass an iocb to generic_atomic_write_valid()

Use ktime_get_ns instead of ktime_get_real_ns when computing the lr_timeout
not to be affected by system time jumps.

Use a boolean instead of the MAX_JIFFY_OFFSET value to determine whether
the next_wakeup value has been set. Comparing elr->lr_next_sched to
MAX_JIFFY_OFFSET can cause the lazyinit thread to loop indefinitely.

Co-developed-by: Lukas Skupinski <lukas.skupinski@landisgyr.com>
Signed-off-by: Lukas Skupinski <lukas.skupinski@landisgyr.com>
Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241106134741.26948-2-othacehe@gnu.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Implemented the suggested solution mentioned in the bug
https://bugzilla.kernel.org/show_bug.cgi?id=218820

Preventing the disabling of delayed allocation mode on remount.
delalloc to nodelalloc not permitted anymore
nodelalloc to delalloc permitted, not affected

Signed-off-by: Nicolas Bretz <bretznic@gmail.com>
Link: https://patch.msgid.link/20241014034143.59779-1-bretznic@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

When I enabled ext4 debug for fault injection testing, I encountered the
following warning:

  EXT4-fs error (device sda): ext4_read_inode_bitmap:201: comm fsstress:
         Cannot read inode bitmap - block_group = 8, inode_bitmap = 1051
  WARNING: CPU: 0 PID: 511 at fs/buffer.c:1181 mark_buffer_dirty+0x1b3/0x1d0

The root cause of the issue lies in the improper implementation of ext4's
buffer_head read fault injection. The actual completion of buffer_head
read and the buffer_head fault injection are not atomic, which can lead
to the uptodate flag being cleared on normally used buffer_heads in race
conditions.

[CPU0]           [CPU1]         [CPU2]
ext4_read_inode_bitmap
  ext4_read_bh()
  <bh read complete>
                 ext4_read_inode_bitmap
                   if (buffer_uptodate(bh))
                     return bh
                               jbd2_journal_commit_transaction
                                 __jbd2_journal_refile_buffer
                                   __jbd2_journal_unfile_buffer
                                     __jbd2_journal_temp_unlink_buffer
  ext4_simulate_fail_bh()
    clear_buffer_uptodate
                                      mark_buffer_dirty
                                        <report warning>
                                        WARN_ON_ONCE(!buffer_uptodate(bh))

The best approach would be to perform fault injection in the IO completion
callback function, rather than after IO completion. However, the IO
completion callback function cannot get the fault injection code in sb.

Fix it by passing the result of fault injection into the bh read function,
we simulate faults within the bh read function itself. This requires adding
an extra parameter to the bh read functions that need fault injection.

Fixes: 46f870d690fe ("ext4: simulate various I/O and checksum errors when reading metadata")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Link: https://patch.msgid.link/20240906091746.510163-1-leo.lilong@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

When ctx_set_flags() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:

.../ext4/super.c:2120:1: error: unused function 'ctx_set_flags' [-Werror,-Wunused-function]
 2120 | EXT4_SET_CTX(flags); /* set only */
      | ^~~~~~~~~~~~~~~~~~~

Fix this by marking ctx_*_flags() with __maybe_unused
(mark both for the sake of symmetry).

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20240905163229.140522-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This is the logic behavior and one that we would like to verify
using a generic fstest similar to xfs/546.

Link: https://lore.kernel.org/fstests/20240830152648.GE6216@frogsfrogsfrogs/
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240904084657.1062243-1-amir73il@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

After commit 21175ca434c5 ("ext4: make prefetch_block_bitmaps default"),
we enable 'prefetch_block_bitmaps' by default, but this is not shown in
the '/proc/fs/ext4/sdx/options' procfs interface.

This makes it impossible to distinguish whether the feature is enabled by
default or not, so 'prefetch_block_bitmaps' is shown in the 'options'
procfs interface when prefetch_block_bitmaps is enabled by default.

This makes it easy to notice changes to the default mount options between
versions through the '/proc/fs/ext4/sdx/options' procfs interface.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241008120134.3758097-1-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This patch adds base support for atomic writes via statx getattr.
On bs < ps systems, we can create FS with say bs of 16k. That means
both atomic write min and max unit can be set to 16k for supporting
atomic writes.

Co-developed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>

When we remount filesystem with 'abort' mount option while changing
other mount options as well (as is LTP test doing), we can return error
from the system call after commit d3476f3dad4a ("ext4: don't set
SB_RDONLY after filesystem errors") because the application of mount
option changes detects shutdown filesystem and refuses to do anything.
The behavior of application of other mount options in presence of
'abort' mount option is currently rather arbitary as some mount option
changes are handled before 'abort' and some after it.

Move aborting of the filesystem to the end of remount handling so all
requested changes are properly applied before the filesystem is shutdown
to have a reasonably consistent behavior.

Fixes: d3476f3dad4a ("ext4: don't set SB_RDONLY after filesystem errors")
Reported-by: Jan Stancek <jstancek@redhat.com>
Link: https://lore.kernel.org/all/Zvp6L+oFnfASaoHl@t14s
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Jan Stancek <jstancek@redhat.com>
Link: https://patch.msgid.link/20241004221556.19222-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>