Pull ext2, udf, and quota update from Jan Kara:
 "Some ext2 cleanups, a fix for UDF crash on corrupted media, and one
  quota locking fix"

* tag 'fs_for_4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  quota: Lock s_umount in exclusive mode for Q_XQUOTA{ON,OFF} quotactls.
  udf: Fix BUG on corrupted inode
  ext2: change reusable parameter to true when calling mb_cache_entry_create()
  ext2: remove redundant condition check
  ext2: avoid unnecessary operation in ext2_error()

The function ext2_xattr_set calls brelse(bh) to drop the reference count
of bh. After that, bh may be freed. However, following brelse(bh),
it reads bh->b_data via macro HDR(bh). This may result in a
use-after-free bug. This patch moves brelse(bh) after reading field.

CC: stable@vger.kernel.org
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Jan Kara <jack@suse.cz>

We need to initialize opts.s_mount_opt as zero before using it, else we
may get some unexpected mount options.

Fixes: 088519572ca8 ("ext2: Parse mount options into a dedicated structure")
CC: stable@vger.kernel.org
Signed-off-by: xingaopeng <xingaopeng@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Reusable parameter of mb_cache_entry_create() is bool type,
so it's better to set true instead of 1.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

ext2_xattr_destroy_cache() can handle NULL pointer correctly,
so there is no need to check NULL pointer before calling
ext2_xattr_destroy_cache().

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

If filesystem has already mounted as read-only, then we don't have
to do it again.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Pull ext2 and udf updates from Jan Kara:
 "Small ext2 cleanups and a couple of udf fixes"

* tag 'filesystems_for_v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: remove redundant building macro check
  udf: Drop pack pragma from udf_sb.h
  udf: Drop freed bitmap / table support
  udf: Fix crash during mount
  udf: Prevent write-unsupported filesystem to be remounted read-write
  ext2: cache NULL when both default_acl and acl are NULL
  udf: remove unused variables group_start and nr_groups

If macro CONFIG_QUOTA is not enabled then mount option flag
of usrquota/grpquota will not be set, so we can remove some
building macro check safely in ext2_shwo_options().
Additionally, I think it's better to define EXT2_MOUNT_DAX
regardless macro CONFIG_FS_DAX is enabled just like acl/xattr.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>

Sync syscall to DAX file needs to flush processor cache, but it
currently does not flush to existing DAX files.  This is because
'ext2_da_aops' is set to address_space_operations of existing DAX
files, instead of 'ext2_dax_aops', since S_DAX flag is set after
ext2_set_aops() in the open path.

Similar to ext4, change ext2_iget() to initialize i_flags before
ext2_set_aops().

Fixes: fb094c90748f ("ext2, dax: introduce ext2_dax_aops")
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Suggested-by: Jan Kara <jack@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>

default_acl and acl of newly created inode will be initiated as
ACL_NOT_CACHED in vfs function inode_init_always() and later will be
updated by calling xxx_init_acl() in specific filesystems.  However,
when default_acl and acl are NULL, then they keep the value of
ACL_NOT_CACHED. This patch changes the code to cache NULL for acl /
default_acl in this case to save unnecessary ACL lookup in future.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Jan Kara <jack@suse.cz>