commit fcced95b6ba2a507a83b8b3e0358a8ac16b13e35 upstream.

PAGE_ALIGN(x) macro gives the next highest value which is multiple of
pagesize. But if x is already page aligned then it simply returns x.
So, if x passed is 0 in dax_zero_range() function, that means the
length gets passed as 0 to ->iomap_begin().

In ext2 it then calls ext2_get_blocks -> max_blocks as 0 and hits bug_on
here in ext2_get_blocks().
	BUG_ON(maxblocks == 0);

Instead we should be calling dax_truncate_page() here which takes
care of it. i.e. it only calls dax_zero_range if the offset is not
page/block aligned.

This can be easily triggered with following on fsdax mounted pmem
device.

dd if=/dev/zero of=file count=1 bs=512
truncate -s 0 file

[79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk
[79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff)
[93.793207] ------------[ cut here ]------------
[93.795102] kernel BUG at fs/ext2/inode.c:637!
[93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139
[93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610
<...>
[93.835298] Call Trace:
[93.836253]  <TASK>
[93.837103]  ? lock_acquire+0xf8/0x110
[93.838479]  ? d_lookup+0x69/0xd0
[93.839779]  ext2_iomap_begin+0xa7/0x1c0
[93.841154]  iomap_iter+0xc7/0x150
[93.842425]  dax_zero_range+0x6e/0xa0
[93.843813]  ext2_setsize+0x176/0x1b0
[93.845164]  ext2_setattr+0x151/0x200
[93.846467]  notify_change+0x341/0x4e0
[93.847805]  ? lock_acquire+0xf8/0x110
[93.849143]  ? do_truncate+0x74/0xe0
[93.850452]  ? do_truncate+0x84/0xe0
[93.851739]  do_truncate+0x84/0xe0
[93.852974]  do_sys_ftruncate+0x2b4/0x2f0
[93.854404]  do_syscall_64+0x3f/0x90
[93.855789]  entry_SYSCALL_64_after_hwframe+0x72/0xdc

CC: stable@vger.kernel.org
Fixes: 2aa3048e03d3 ("iomap: switch iomap_zero_range to use iomap_iter")
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <046a58317f29d9603d1068b2bbae47c2332c17ae.1682069716.git.ritesh.list@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull ext2, reiserfs, udf, and quota updates from Jan Kara:
 "A couple of small fixes and cleanups for ext2, udf, reiserfs, and
  quota.

  The biggest change is making CONFIG_PRINT_QUOTA_WARNING depend on
  BROKEN with an outlook for removing it completely in an year or so"

* tag 'fs_for_v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  quota: mark PRINT_QUOTA_WARNING as BROKEN
  quota: update Kconfig comment
  reiserfs: remove unused iter variable
  quota: Use register_sysctl_init() for registering fs_dqstats_table
  reiserfs: remove unused sched_count variable
  ext2: remove redundant assignment to pointer end
  quota: make dquot_set_dqinfo return errors from ->write_info
  quota: fixup *_write_file_info() to return proper error code
  quota: simplify two-level sysctl registration for fs_dqstats_table
  udf: use wrapper i_blocksize() in udf_discard_prealloc()
  udf: Use folios in udf_adinicb_writepage()
  ext2: Check block size validity during mount
  ext2: Correct maximum ext2 filesystem block size

Pointer is assigned a value that is never read, the assignment is
redundant and can be removed.

Cleans up clang-scan warning:
fs/ext2/xattr.c:555:3: warning: Value stored to 'end' is never read [deadcode.DeadStores]
                end = (char *)header + sb->s_blocksize;

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230317143420.419005-1-colin.i.king@gmail.com>

Check that log of block size stored in the superblock has sensible
value. Otherwise the shift computing the block size can overflow leading
to undefined behavior.

Reported-by: syzbot+4fec412f59eba8c01b77@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>

Ext2 has traditionally supported filesystem block sizes upto page size
or upto 65536. Macro EXT2_MAX_BLOCK_SIZE is set to 4096, however that is
never used in ext2 so practically we always allowed whatever
sb_set_blocksize() accepted. Fix value of EXT2_MAX_BLOCK_SIZE because it
will be used in the next patch.

Signed-off-by: Jan Kara <jack@suse.cz>

Reflect in their naming and document that they are kept around for
legacy reasons and shouldn't be used anymore by new code.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

The ext{2,4}, erofs, f2fs, and jffs2 filesystems use the same logic to
check whether a given xattr can be listed. Simplify them and avoid
open-coding the same check by calling the helper we introduced earlier.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: linux-erofs@lists.ozlabs.org
Cc: linux-ext4@vger.kernel.org
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Remove struct posix_acl_{access,default}_handler for all filesystems
that don't depend on the xattr handler in their inode->i_op->listxattr()
method in any way. There's nothing more to do than to simply remove the
handler. It's been effectively unused ever since we introduced the new
posix acl api.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

Pull legacy dio update from Jens Axboe:
 "We only have a few file systems that use the old dio code, make them
  select it rather than build it unconditionally"

* tag 'for-6.3/dio-2023-02-16' of git://git.kernel.dk/linux:
  fs: build the legacy direct I/O code conditionally
  fs: move sb_init_dio_done_wq out of direct-io.c

Pull UDF and ext2 fixes from Jan Kara:

 - Rewrite of udf directory iteration code to address multiple syzbot
   reports

 - Fixes to udf extent handling and block mapping code to address
   several syzbot reports and filesystem corruption issues uncovered by
   fsx & fsstress

 - Convert udf to kmap_local()

 - Add sanity checks when loading udf bitmaps

 - Drop old VARCONV support which I've never seen used and which was
   broken for quite some years without anybody noticing

 - Finish conversion of ext2 to kmap_local()

 - One fix to mpage_writepages() on which other udf fixes depend

* tag 'fixes_for_v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (78 commits)
  udf: Avoid directory type conversion failure due to ENOMEM
  udf: Use unsigned variables for size calculations
  udf: remove reporting loc in debug output
  udf: Check consistency of Space Bitmap Descriptor
  udf: Fix file counting in LVID
  udf: Limit file size to 4TB
  udf: Don't return bh from udf_expand_dir_adinicb()
  udf: Convert udf_expand_file_adinicb() to avoid kmap_atomic()
  udf: Convert udf_adinicb_writepage() to memcpy_to_page()
  udf: Switch udf_adinicb_readpage() to kmap_local_page()
  udf: Move udf_adinicb_readpage() to inode.c
  udf: Mark aops implementation static
  udf: Switch to single address_space_operations
  udf: Add handling of in-ICB files to udf_bmap()
  udf: Convert all file types to use udf_write_end()
  udf: Convert in-ICB files to use udf_write_begin()
  udf: Convert in-ICB files to use udf_direct_IO()
  udf: Convert in-ICB files to use udf_writepages()
  udf: Unify .read_folio for normal and in-ICB files
  udf: Fix off-by-one error when discarding preallocation
  ...