It is possible that unlinked inode enters ext4_setattr() (e.g. if
somebody calls ftruncate(2) on unlinked but still open file). In such
case we should not delete the inode from the orphan list if truncate
fails. Note that this is mostly a theoretical concern as filesystem is
corrupted if we reach this path anyway but let's be consistent in our
orphan handling.
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

We didn't wait for outstanding direct IO during truncate in nojournal
mode (as we skip orphan handling in that case). This can lead to fs
corruption or stale data exposure if truncate ends up freeing blocks
and these get reallocated before direct IO finishes. Fix the condition
determining whether the wait is necessary.

CC: stable@vger.kernel.org
Fixes: 1c9114f9 ("ext4: serialize unlocked dio reads with truncate")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Since the journal inode is already checked when we added it to the
block validity's system zone, if we check it again, we'll just trigger
a failure.

This was causing failures like this:

[   53.897001] EXT4-fs error (device sda): ext4_find_extent:909: inode
#8: comm jbd2/sda-8: pblk 121667583 bad header/extent: invalid extent entries - magic f30a, entries 8, max 340(340), depth 0(0)
[   53.931430] jbd2_journal_bmap: journal block not found at offset 49 on sda-8
[   53.938480] Aborting journal on device sda-8.

... but only if the system was under enough memory pressure that
logical->physical mapping for the journal inode gets pushed out of the
extent cache.  (This is why it wasn't noticed earlier.)

Fixes: 345c0dbf ("ext4: protect journal inode's blocks using block_validity")
Reported-by: Dan Rue <dan.rue@linaro.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>

Handling of aborted journal is a special code path different from
standard ext4_error() one and it can call panic() as well. Commit
1dc1097f ("ext4: avoid panic during forced reboot") forgot to update
this path so fix that omission.

Fixes: 1dc1097f ("ext4: avoid panic during forced reboot")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 5.1

Commit 345c0dbf ("ext4: protect journal inode's blocks using
block_validity") failed to add an exception for the journal inode in
ext4_check_blockref(), which is the function used by ext4_get_branch()
for indirect blocks.  This caused attempts to read from the ext3-style
journals to fail with:

[  848.968550] EXT4-fs error (device sdb7): ext4_get_branch:171: inode #8: block 30343695: comm jbd2/sdb7-8: invalid block

Fix this by adding the missing exception check.

Fixes: 345c0dbf ("ext4: protect journal inode's blocks using block_validity")
Reported-by: Arthur Marsh <arthur.marsh@internode.on.net>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

There are two cases where u32 variables n and err are being checked
for less than zero error values, the checks is always false because
the variables are not signed. Fix this by making the variables ints.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 345c0dbf ("ext4: protect journal inode's blocks using block_validity")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The buffer_head (frames[0].bh) and it's corresping page can be
potentially free'd once brelse() is done inside the for loop
but before the for loop exits in dx_release(). It can be free'd
in another context, when the page cache is flushed via
drop_caches_sysctl_handler(). This results into below data abort
when accessing info->indirect_levels in dx_release().

Unable to handle kernel paging request at virtual address ffffffc17ac3e01e
Call trace:
 dx_release+0x70/0x90
 ext4_htree_fill_tree+0x2d4/0x300
 ext4_readdir+0x244/0x6f8
 iterate_dir+0xbc/0x160
 SyS_getdents64+0x94/0x174
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: stable@kernel.org

Unaligned AIO must be serialized because the zeroing of partial blocks
of unaligned AIO can result in data corruption in case it's overlapping
another in flight IO.

Currently we wait for all unwritten extents before we submit unaligned
AIO which protects data in case of unaligned AIO is following overlapping
IO. However if a unaligned AIO is followed by overlapping aligned AIO we
can still end up corrupting data.

To fix this, we must make sure that the unaligned AIO is the only IO in
flight by waiting for unwritten extents conversion not just before the
IO submission, but right after it as well.

This problem can be reproduced by xfstest generic/538
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

When failing from creating cache jbd2_inode_cache, we will destroy the
previously created cache jbd2_handle_cache twice.  This patch fixes
this by moving each cache initialization/destruction to its own
separate, individual function.
Signed-off-by: Chengguang Xu <cgxu519@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

This commit zeroes out the unused memory region in the buffer_head
corresponding to the extent metablock after writing the extent header
and the corresponding extent node entries.

This is done to prevent random uninitialized data from getting into
the filesystem when the extent block is synced.

This fixes CVE-2019-11833.
Signed-off-by: Sriram Rajagopalan <sriramr@arista.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Instead of removing EXT4_MOUNT_JOURNAL_CHECKSUM from s_def_mount_opt as
I assume was intended, all other options were blown away leading to
_ext4_show_options() output being incorrect.

Fixes: 1e381f60 ("ext4: do not allow journal_opts for fs w/o journal")
Signed-off-by: Debabrata Banerjee <dbanerje@akamai.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org

scripts/mkutf8data is used only when regenerating utf8data.h,
which never happens in the normal kernel build. However, it is
irrespectively built if CONFIG_UNICODE is enabled.

Moreover, there is no good reason for it to reside in the scripts/
directory since it is only used in fs/unicode/.

Hence, move it from scripts/ to fs/unicode/.

In some cases, we bypass build artifacts in the normal build. The
conventional way to do so is to surround the code with ifdef REGENERATE_*.

For example,

 - 7373f4f8 ("kbuild: add implicit rules for parser generation")
 - 6aaf49b4 ("crypto: arm,arm64 - Fix random regeneration of S_shipped")

I rewrote the rule in a more kbuild'ish style.

In the normal build, utf8data.h is just shipped from the check-in file.

$ make
  [ snip ]
  SHIPPED fs/unicode/utf8data.h
  CC      fs/unicode/utf8-norm.o
  CC      fs/unicode/utf8-core.o
  CC      fs/unicode/utf8-selftest.o
  AR      fs/unicode/built-in.a

If you want to generate utf8data.h based on UCD, put *.txt files into
fs/unicode/, then pass REGENERATE_UTF8DATA=1 from the command line.
The mkutf8data tool will be automatically compiled to generate the
utf8data.h from the *.txt files.

$ make REGENERATE_UTF8DATA=1
  [ snip ]
  HOSTCC  fs/unicode/mkutf8data
  GEN     fs/unicode/utf8data.h
  CC      fs/unicode/utf8-norm.o
  CC      fs/unicode/utf8-core.o
  CC      fs/unicode/utf8-selftest.o
  AR      fs/unicode/built-in.a

I renamed the check-in utf8data.h to utf8data.h_shipped so that this
will work for the out-of-tree build.

You can update it based on the latest UCD like this:

$ make REGENERATE_UTF8DATA=1 fs/unicode/
$ cp fs/unicode/utf8data.h fs/unicode/utf8data.h_shipped

Also, I added entries to .gitignore and dontdiff.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Introduces the case-insensitive features on ext4 for system
administrators.  Explain the minimum of design decisions that are
important for sysadmins wanting to enable this feature.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This patch implements the actual support for case-insensitive file name
lookups in ext4, based on the feature bit and the encoding stored in the
superblock.

A filesystem that has the casefold feature set is able to configure
directories with the +F (EXT4_CASEFOLD_FL) attribute, enabling lookups
to succeed in that directory in a case-insensitive fashion, i.e: match
a directory entry even if the name used by userspace is not a byte per
byte match with the disk name, but is an equivalent case-insensitive
version of the Unicode string.  This operation is called a
case-insensitive file name lookup.

The feature is configured as an inode attribute applied to directories
and inherited by its children.  This attribute can only be enabled on
empty directories for filesystems that support the encoding feature,
thus preventing collision of file names that only differ by case.

* dcache handling:

For a +F directory, Ext4 only stores the first equivalent name dentry
used in the dcache. This is done to prevent unintentional duplication of
dentries in the dcache, while also allowing the VFS code to quickly find
the right entry in the cache despite which equivalent string was used in
a previous lookup, without having to resort to ->lookup().

d_hash() of casefolded directories is implemented as the hash of the
casefolded string, such that we always have a well-known bucket for all
the equivalencies of the same string. d_compare() uses the
utf8_strncasecmp() infrastructure, which handles the comparison of
equivalent, same case, names as well.

For now, negative lookups are not inserted in the dcache, since they
would need to be invalidated anyway, because we can't trust missing file
dentries.  This is bad for performance but requires some leveraging of
the vfs layer to fix.  We can live without that for now, and so does
everyone else.

* on-disk data:

Despite using a specific version of the name as the internal
representation within the dcache, the name stored and fetched from the
disk is a byte-per-byte match with what the user requested, making this
implementation 'name-preserving'. i.e. no actual information is lost
when writing to storage.

DX is supported by modifying the hashes used in +F directories to make
them case/encoding-aware.  The new disk hashes are calculated as the
hash of the full casefolded string, instead of the string directly.
This allows us to efficiently search for file names in the htree without
requiring the user to provide an exact name.

* Dealing with invalid sequences:

By default, when a invalid UTF-8 sequence is identified, ext4 will treat
it as an opaque byte sequence, ignoring the encoding and reverting to
the old behavior for that unique file.  This means that case-insensitive
file name lookup will not work only for that file.  An optional bit can
be set in the superblock telling the filesystem code and userspace tools
to enforce the encoding.  When that optional bit is set, any attempt to
create a file name using an invalid UTF-8 sequence will fail and return
an error to userspace.

* Normalization algorithm:

The UTF-8 algorithms used to compare strings in ext4 is implemented
lives in fs/unicode, and is based on a previous version developed by
SGI.  It implements the Canonical decomposition (NFD) algorithm
described by the Unicode specification 12.1, or higher, combined with
the elimination of ignorable code points (NFDi) and full
case-folding (CF) as documented in fs/unicode/utf8_norm.c.

NFD seems to be the best normalization method for EXT4 because:

  - It has a lower cost than NFC/NFKC (which requires
    decomposing to NFD as an intermediary step)
  - It doesn't eliminate important semantic meaning like
    compatibility decompositions.

Although:

  - This implementation is not completely linguistic accurate, because
  different languages have conflicting rules, which would require the
  specialization of the filesystem to a given locale, which brings all
  sorts of problems for removable media and for users who use more than
  one language.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Support for encoding is considered an incompatible feature, since it has
potential to create collisions of file names in existing filesystems.
If the feature flag is not enabled, the entire filesystem will operate
on opaque byte sequences, respecting the original behavior.

The s_encoding field stores a magic number indicating the encoding
format and version used globally by file and directory names in the
filesystem.  The s_encoding_flags defines policies for using the charset
encoding, like how to handle invalid sequences.  The magic number is
mapped to the exact charset table, but the mapping is specific to ext4.
Since we don't have any commitment to support old encodings, the only
encoding I am supporting right now is utf8-12.1.0.

The current implementation prevents the user from enabling encoding and
per-directory encryption on the same filesystem at the same time.  The
incompatibility between these features lies in how we do efficient
directory searches when we cannot be sure the encryption of the user
provided fname will match the actual hash stored in the disk without
decrypting every directory entry, because of normalization cases.  My
quickest solution is to simply block the concurrent use of these
features for now, and enable it later, once we have a better solution.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Regenerate utf8data.h based on the latest UCD files and run tests
against the latest version.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This implements a in-kernel sanity test module for the utf8
normalization core.  At probe time, it will run basic sequences through
the utf8n core, to identify problems will equivalent sequences and
normalization/casefold code.  This is supposed to be useful for
regression testing when adding support for a new version of utf8 to
linux.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This patch integrates the utf8n patches with some higher level API to
perform UTF-8 string comparison, normalization and casefolding
operations.  Implemented is a variation of NFD, and casefold is
performed by doing full casefold on top of NFD.  These algorithms are
based on the core implemented by Olaf Weber from SGI.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Remove the Hangul decompositions from the utf8data trie, and do
algorithmic decomposition to calculate them on the fly. To store the
decomposition the caller of utf8lookup()/utf8nlookup() must provide a
12-byte buffer, which is used to synthesize a leaf with the
decomposition. This significantly reduces the size of the utf8data[]
array.

Changes made by Gabriel:
  Rebase to mainline
  Fix checkpatch errors
  Extract robustness fixes and merge back to original mkutf8data.c patch
  Regenerate utf8data.h
Signed-off-by: Olaf Weber <olaf@sgi.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Supporting functions for UTF-8 normalization are in utf8norm.c with the
header utf8norm.h. Two normalization forms are supported: nfdi and
nfdicf.

  nfdi:
   - Apply unicode normalization form NFD.
   - Remove any Default_Ignorable_Code_Point.

  nfdicf:
   - Apply unicode normalization form NFD.
   - Remove any Default_Ignorable_Code_Point.
   - Apply a full casefold (C + F).

For the purposes of the code, a string is valid UTF-8 if:

 - The values encoded are 0x1..0x10FFFF.
 - The surrogate codepoints 0xD800..0xDFFFF are not encoded.
 - The shortest possible encoding is used for all values.

The supporting functions work on null-terminated strings (utf8 prefix)
and on length-limited strings (utf8n prefix).

From the original SGI patch and for conformity with coding standards,
the utf8data_t typedef was dropped, since it was just masking the struct
keyword.  On other occasions, namely utf8leaf_t and utf8trie_t, I
decided to keep it, since they are simple pointers to memory buffers,
and using uchars here wouldn't provide any more meaningful information.

From the original submission, we also converted from the compatibility
form to canonical.

Changes made by Gabriel:
  Rebase to Mainline
  Fix up checkpatch.pl warnings
  Drop typedefs
  move out of libxfs
  Convert from NFKD to NFD
Signed-off-by: Olaf Weber <olaf@sgi.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

The decomposition and casefolding of UTF-8 characters are described in a
prefix tree in utf8data.h, which is a generate from the Unicode
Character Database (UCD), published by the Unicode Consortium, and
should not be edited by hand.  The structures in utf8data.h are meant to
be used for lookup operations by the unicode subsystem, when decoding a
utf-8 string.

mkutf8data.c is the source for a program that generates utf8data.h. It
was written by Olaf Weber from SGI and originally proposed to be merged
into Linux in 2014.  The original proposal performed the compatibility
decomposition, NFKD, but the current version was modified by me to do
canonical decomposition, NFD, as suggested by the community.  The
changes from the original submission are:

  * Rebase to mainline.
  * Fix out-of-tree-build.
  * Update makefile to build 11.0.0 ucd files.
  * drop references to xfs.
  * Convert NFKD to NFD.
  * Merge back robustness fixes from original patch. Requested by
    Dave Chinner.

The original submission is archived at:

<https://linux-xfs.oss.sgi.narkive.com/Xx10wjVY/rfc-unicode-utf-8-support-for-xfs>

The utf8data.h file can be regenerated using the instructions in
fs/unicode/README.utf8data.

- Notes on the update from 8.0.0 to 11.0:

The structure of the ucd files and special cases have not experienced
any changes between versions 8.0.0 and 11.0.0.  8.0.0 saw the addition
of Cherokee LC characters, which is an interesting case for
case-folding.  The update is accompanied by new tests on the test_ucd
module to catch specific cases.  No changes to mkutf8data script were
required for the updates.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

It is never possible, that number of block groups decreases,
since only online grow is supported.

But after a growing occured, we have to zero inode tables
for just created new block groups.

Fixes: 19c5246d ("ext4: add new online resize interface")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org

Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>

When remounting with debug_want_extra_isize, we were not performing the
same checks that we do during a normal mount.  That allowed us to set a
value for s_want_extra_isize that reached outside the s_inode_size.

Fixes: e2b911c5 ("ext4: clean up feature test macros with predicate functions")
Reported-by: syzbot+f584efa0ac7213c226b7@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Barret Rhoden <brho@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

The reference to iloc.bh has been dropped in ext4_mark_iloc_dirty.
However, the reference is dropped again if error occurs during
ext4_handle_dirty_metadata, which may result in use-after-free bugs.

Fixes: fb265c9c("ext4: add ext4_sb_bread() to disambiguate ENOMEM cases")
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org

In other places in fs/ext4/xattr.c, if e_value_inum is non-zero, the
code ignores the value in e_value_offs.  The e_value_offs *should* be
zero, but we shouldn't depend upon it, since it might not be true in a
corrupted/fuzzed file system.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202897
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202877Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

Add the blocks which belong to the journal inode to block_validity's
system zone so attempts to deallocate or overwrite the journal due a
corrupted file system where the journal blocks are also claimed by
another inode.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202879Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

BUG_ON(1) leads to bogus warnings from clang when
CONFIG_PROFILE_ANNOTATED_BRANCHES is set:

 fs/ext4/inode.c:544:4: error: variable 'retval' is used uninitialized whenever 'if' condition is false
      [-Werror,-Wsometimes-uninitialized]
                        BUG_ON(1);
                        ^~~~~~~~~
 include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
                                   ^~~~~~~~~~~~~~~~~~~
 include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 fs/ext4/inode.c:591:6: note: uninitialized use occurs here
        if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
            ^~~~~~
 fs/ext4/inode.c:544:4: note: remove the 'if' if its condition is always true
                        BUG_ON(1);
                        ^
 include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
                               ^
 fs/ext4/inode.c:502:12: note: initialize the variable 'retval' to silence this warning

Change it to BUG() so clang can see that this code path can never
continue.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>

In ext4_mpage_readpages(), if the parameter pages is not NULL, another
parameter page is NULL. At the first time prefetchw(&page->flags)
works on NULL. From second time, prefetchw(&page->flags) always works on
the last consumed page. This might do little improvment for handling
current page. So prefetchw() should be called while the page pointer
has just been updated.
Signed-off-by: Liu Xiang <liu.xiang6@zte.com.cn>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

We hit a BUG at fs/buffer.c:3057 if we detached the nbd device
before unmounting ext4 filesystem.

The typical chain of events leading to the BUG:
jbd2_write_superblock
  submit_bh
    submit_bh_wbc
      BUG_ON(!buffer_mapped(bh));

The block device is removed and all the pages are invalidated. JBD2
was trying to write journal superblock to the block device which is
no longer present.

Fix this by checking the journal superblock's buffer head prior to
submitting.
Reported-by: Eric Ren <renzhen@linux.alibaba.com>
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org

The comment above NEXT_ORPHAN() was meant for ext4_encrypted_inode(),
which was moved by commit a7550b30 ("ext4 crypto: migrate into vfs's
crypto engine") but the comment was accidentally left in place.  Since
ext4_encrypted_inode() has now been removed, just remove the comment.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

The sanity check in mb_find_extent() only checked that returned extent
does not extend past blocksize * 8, however it should not extend past
EXT4_CLUSTERS_PER_GROUP(sb). This can happen when clusters_per_group <
blocksize * 8 and the tail of the bitmap is not properly filled by 1s
which happened e.g. when ancient kernels have grown the filesystem.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

At the beginning, nblocks has been assigned. There is no need
to repeat the assignment in the while loop, and remove it.
Signed-off-by: Liu Song <liu.song11@zte.com.cn>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

Pull KVM fixes from Paolo Bonzini:
 "A collection of x86 and ARM bugfixes, and some improvements to
  documentation.

  On top of this, a cleanup of kvm_para.h headers, which were exported
  by some architectures even though they not support KVM at all. This is
  responsible for all the Kbuild changes in the diffstat"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (28 commits)
  Documentation: kvm: clarify KVM_SET_USER_MEMORY_REGION
  KVM: doc: Document the life cycle of a VM and its resources
  KVM: selftests: complete IO before migrating guest state
  KVM: selftests: disable stack protector for all KVM tests
  KVM: selftests: explicitly disable PIE for tests
  KVM: selftests: assert on exit reason in CR4/cpuid sync test
  KVM: x86: update %rip after emulating IO
  x86/kvm/hyper-v: avoid spurious pending stimer on vCPU init
  kvm/x86: Move MSR_IA32_ARCH_CAPABILITIES to array emulated_msrs
  KVM: x86: Emulate MSR_IA32_ARCH_CAPABILITIES on AMD hosts
  kvm: don't redefine flags as something else
  kvm: mmu: Used range based flushing in slot_handle_level_range
  KVM: export <linux/kvm_para.h> and <asm/kvm_para.h> iif KVM is supported
  KVM: x86: remove check on nr_mmu_pages in kvm_arch_commit_memory_region()
  kvm: nVMX: Add a vmentry check for HOST_SYSENTER_ESP and HOST_SYSENTER_EIP fields
  KVM: SVM: Workaround errata#1096 (insn_len maybe zero on SMAP violation)
  KVM: Reject device ioctls from processes other than the VM's creator
  KVM: doc: Fix incorrect word ordering regarding supported use of APIs
  KVM: x86: fix handling of role.cr4_pae and rename it to 'gpte_size'
  KVM: nVMX: Do not inherit quadrant and invalid for the root shadow EPT
  ...