DAX page fault path needs to get blocks that are pre-zeroed to avoid
races when two concurrent page faults happen in the same block of a
file. Implement support for this in ext4_map_blocks().
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Create new function ext4_issue_zeroout() to zeroout contiguous (both
logically and physically) part of inode data. We will need to issue
zeroout when extent structure is not readily available and this function
will allow us to do it without making up fake extent structures.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When dioread_nolock mode is enabled, we grab i_data_sem in
ext4_ext_direct_IO() and therefore we need to instruct _ext4_get_block()
not to grab i_data_sem again using EXT4_GET_BLOCKS_NO_LOCK. However
holding i_data_sem over overwrite direct IO isn't needed these days. We
have exclusion against truncate / hole punching because we increase
i_dio_count under i_mutex in ext4_ext_direct_IO() so once
ext4_file_write_iter() verifies blocks are allocated & written, they are
guaranteed to stay so during the whole direct IO even after we drop
i_mutex.
So we can just remove this locking abuse and the no longer necessary
EXT4_GET_BLOCKS_NO_LOCK flag.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When doing delayed allocation, update of on-disk inode size is postponed
until IO submission time. However hole punch or zero range fallocate
calls can end up discarding the tail page cache page and thus on-disk
inode size would never be properly updated.
Make sure the on-disk inode size is updated before truncating page
cache.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, page faults and hole punching are completely unsynchronized.
This can result in page fault faulting in a page into a range that we
are punching after truncate_pagecache_range() has been called and thus
we can end up with a page mapped to disk blocks that will be shortly
freed. Filesystem corruption will shortly follow. Note that the same
race is avoided for truncate by checking page fault offset against
i_size but there isn't similar mechanism available for punching holes.
Fix the problem by creating new rw semaphore i_mmap_sem in inode and
grab it for writing over truncate, hole punching, and other functions
removing blocks from extent tree and for read over page faults. We
cannot easily use i_data_sem for this since that ranks below transaction
start and we need something ranking above it so that it can be held over
the whole truncate / hole punching operation. Also remove various
workarounds we had in the code to reduce race window when page fault
could have created pages with stale mapping information.
Signed-off-by: Jan Kara <jack@suse.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
In ext4, the bottom two bits of {a,c,m}time_extra are used to extend
the {a,c,m}time fields, deferring the year 2038 problem to the year
2446.
When decoding these extended fields, for times whose bottom 32 bits
would represent a negative number, sign extension causes the 64-bit
extended timestamp to be negative as well, which is not what's
intended. This patch corrects that issue, so that the only negative
{a,c,m}times are those between 1901 and 1970 (as per 32-bit signed
timestamps).
Some older kernels might have written pre-1970 dates with 1,1 in the
extra bits. This patch treats those incorrectly-encoded dates as
pre-1970, instead of post-2311, until kernel 4.20 is released.
Hopefully by then e2fsck will have fixed up the bad data.
Also add a comment explaining the encoding of ext4's extra {a,c,m}time
bits.
Signed-off-by: David Turner <novalis@novalis.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Mark Harris <mh8928@yahoo.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=23732
Cc: stable@vger.kernel.org
It is appeared that we can pass journal related mount options and such options
be shown in /proc/mounts
Example:
#mkfs.ext4 -F /dev/vdb
#tune2fs -O ^has_journal /dev/vdb
#mount /dev/vdb /mnt/ -ocommit=20,journal_async_commit
#cat /proc/mounts | grep /mnt
/dev/vdb /mnt ext4 rw,relatime,journal_checksum,journal_async_commit,commit=20,data=ordered 0 0
But options:"journal_checksum,journal_async_commit,commit=20,data=ordered" has
nothing with reality because there is no journal at all.
This patch disallow following options for journalless configurations:
- journal_checksum
- journal_async_commit
- commit=%ld
- data={writeback,ordered,journal}
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Create separate predicate functions to test/set/clear feature flags,
thereby replacing the wordy old macros. Furthermore, clean out the
places where we open-coded feature tests.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Instead of overloading EIO for CRC errors and corrupt structures,
return the same error codes that XFS returns for the same issues.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Allow the filesystem to store the metadata checksum seed in the
superblock and add an incompat feature to say that we're using it.
This enables tune2fs to change the UUID on a mounted metadata_csum
FS without having to (racy!) rewrite all disk metadata.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Since ext4_page_crypto() doesn't need an encryption context (at least
not any more), this allows us to simplify a number function signature
and also allows us to avoid needing to allocate a context in
ext4_block_write_begin(). It also means we no longer need a separate
ext4_decrypt_one() function.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This allows us to refactor the procfs code, which saves a bit of
compiled space. More importantly it isolates most of the procfs
support code into a single file, so it's easier to #ifdef it out if
the proc file system has been disabled.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Also statically allocate the ext4_kset and ext4_feat objects, since we
only need exactly one of each, and it's simpler and less code if we
drop the dynamic allocation and deallocation when it's not needed.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
DAX wants different semantics from any currently-existing ext4 get_block
callback. Unlike ext4_get_block_write(), it needs to honour the
'create' flag, and unlike ext4_get_block(), it needs to be able to
return unwritten extents. So introduce a new ext4_get_block_dax() which
has those semantics.
We could also change ext4_get_block_write() to honour the 'create' flag,
but that might have consequences on other users that I do not currently
understand.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ext4_io_submit_init() takes the pointer to writeback_control to test
its sync_mode and determine between WRITE and WRITE_SYNC and records
the result in ->io_op. This patch makes it record the pointer
directly and moves the test to ext4_io_submit().
This doesn't cause any noticeable differences now but having
writeback_control available throughout IO submission path will be
depended upon by the planned cgroup writeback support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
the ext4 encryption patches, which is a new feature added in the last
merge window. Also fix a number of long-standing xfstest failures.
(Quota writes failing due to ENOSPC, a race between truncate and
writepage in data=journalled mode that was causing generic/068 to
fail, and other corner cases.)
Also add support for FALLOC_FL_INSERT_RANGE, and improve jbd2
performance eliminating locking when a buffer is modified more than
once during a transaction (which is very common for allocation
bitmaps, for example), in which case the state of the journalled
buffer head doesn't need to change.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"A very large number of cleanups and bug fixes --- in particular for
the ext4 encryption patches, which is a new feature added in the last
merge window. Also fix a number of long-standing xfstest failures.
(Quota writes failing due to ENOSPC, a race between truncate and
writepage in data=journalled mode that was causing generic/068 to
fail, and other corner cases.)
Also add support for FALLOC_FL_INSERT_RANGE, and improve jbd2
performance eliminating locking when a buffer is modified more than
once during a transaction (which is very common for allocation
bitmaps, for example), in which case the state of the journalled
buffer head doesn't need to change"
[ I renamed "ext4_follow_link()" to "ext4_encrypted_follow_link()" in
the merge resolution, to make it clear that that function is _only_
used for encrypted symlinks. The function doesn't actually work for
non-encrypted symlinks at all, and they use the generic helpers
- Linus ]
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (52 commits)
ext4: set lazytime on remount if MS_LAZYTIME is set by mount
ext4: only call ext4_truncate when size <= isize
ext4: make online defrag error reporting consistent
ext4: minor cleanup of ext4_da_reserve_space()
ext4: don't retry file block mapping on bigalloc fs with non-extent file
ext4: prevent ext4_quota_write() from failing due to ENOSPC
ext4: call sync_blockdev() before invalidate_bdev() in put_super()
jbd2: speedup jbd2_journal_dirty_metadata()
jbd2: get rid of open coded allocation retry loop
ext4: improve warning directory handling messages
jbd2: fix ocfs2 corrupt when updating journal superblock fails
ext4: mballoc: avoid 20-argument function call
ext4: wait for existing dio workers in ext4_alloc_file_blocks()
ext4: recalculate journal credits as inode depth changes
jbd2: use GFP_NOFS in jbd2_cleanup_journal_tail()
ext4: use swap() in mext_page_double_lock()
ext4: use swap() in memswap()
ext4: fix race between truncate and __ext4_journalled_writepage()
ext4 crypto: fail the mount if blocksize != pagesize
ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate
...
Pull vfs updates from Al Viro:
"In this pile: pathname resolution rewrite.
- recursion in link_path_walk() is gone.
- nesting limits on symlinks are gone (the only limit remaining is
that the total amount of symlinks is no more than 40, no matter how
nested).
- "fast" (inline) symlinks are handled without leaving rcuwalk mode.
- stack footprint (independent of the nesting) is below kilobyte now,
about on par with what it used to be with one level of nested
symlinks and ~2.8 times lower than it used to be in the worst case.
- struct nameidata is entirely private to fs/namei.c now (not even
opaque pointers are being passed around).
- ->follow_link() and ->put_link() calling conventions had been
changed; all in-tree filesystems converted, out-of-tree should be
able to follow reasonably easily.
For out-of-tree conversions, see Documentation/filesystems/porting
for details (and in-tree filesystems for examples of conversion).
That has sat in -next since mid-May, seems to survive all testing
without regressions and merges clean with v4.1"
* 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (131 commits)
turn user_{path_at,path,lpath,path_dir}() into static inlines
namei: move saved_nd pointer into struct nameidata
inline user_path_create()
inline user_path_parent()
namei: trim do_last() arguments
namei: stash dfd and name into nameidata
namei: fold path_cleanup() into terminate_walk()
namei: saner calling conventions for filename_parentat()
namei: saner calling conventions for filename_create()
namei: shift nameidata down into filename_parentat()
namei: make filename_lookup() reject ERR_PTR() passed as name
namei: shift nameidata inside filename_lookup()
namei: move putname() call into filename_lookup()
namei: pass the struct path to store the result down into path_lookupat()
namei: uninline set_root{,_rcu}()
namei: be careful with mountpoint crossings in follow_dotdot_rcu()
Documentation: remove outdated information from automount-support.txt
get rid of assorted nameidata-related debris
lustre: kill unused helper
lustre: kill unused macro (LOOKUP_CONTINUE)
...
Several ext4_warning() messages in the directory handling code do not
report the inode number of the (potentially corrupt) directory where a
problem is seen, and others report this in an ad-hoc manner. Add an
ext4_warning_inode() helper to print the inode number and command name
consistent with ext4_error_inode().
Consolidate the place in ext4.h that these macros are defined.
Clean up some other directory error and warning messages to print the
calling function name.
Minor code style fixes in nearby lines.
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This patch implements fallocate's FALLOC_FL_INSERT_RANGE for Ext4.
1) Make sure that both offset and len are block size aligned.
2) Update the i_size of inode by len bytes.
3) Compute the file's logical block number against offset. If the computed
block number is not the starting block of the extent, split the extent
such that the block number is the starting block of the extent.
4) Shift all the extents which are lying between [offset, last allocated extent]
towards right by len bytes. This step will make a hole of len bytes
at offset.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Previously we were taking the required padding when allocating space
for the on-disk symlink. This caused a buffer overrun which could
trigger a krenel crash when running fsstress.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Factor out calls to ext4_inherit_context() and move them to
__ext4_new_inode(); this fixes a problem where ext4_tmpfile() wasn't
calling calling ext4_inherit_context(), so the temporary file wasn't
getting protected. Since the blocks for the tmpfile could end up on
disk, they really should be protected if the tmpfile is created within
the context of an encrypted directory.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
As suggested by Herbert Xu, we shouldn't allocate a new tfm each time
we read or write a page. Instead we can use a single tfm hanging off
the inode's crypt_info structure for all of our encryption needs for
that inode, since the tfm can be used by multiple crypto requests in
parallel.
Also use cmpxchg() to avoid races that could result in crypt_info
structure getting doubly allocated or doubly freed.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for
slighly better memory efficiency and debuggability.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The superblock fields s_file_encryption_mode and s_dir_encryption_mode
are vestigal, so remove them as a cleanup. While we're at it, allow
file systems with both encryption and inline_data enabled at the same
time to work correctly. We can't have encrypted inodes with inline
data, but there's no reason to prohibit unencrypted inodes from using
the inline data feature.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This is a pretty massive patch which does a number of different things:
1) The per-inode encryption information is now stored in an allocated
data structure, ext4_crypt_info, instead of directly in the node.
This reduces the size usage of an in-memory inode when it is not
using encryption.
2) We drop the ext4_fname_crypto_ctx entirely, and use the per-inode
encryption structure instead. This remove an unnecessary memory
allocation and free for the fname_crypto_ctx as well as allowing us
to reuse the ctfm in a directory for multiple lookups and file
creations.
3) We also cache the inode's policy information in the ext4_crypt_info
structure so we don't have to continually read it out of the
extended attributes.
4) We now keep the keyring key in the inode's encryption structure
instead of releasing it after we are done using it to derive the
per-inode key. This allows us to test to see if the key has been
revoked; if it has, we prevent the use of the derived key and free
it.
5) When an inode is released (or when the derived key is freed), we
will use memset_explicit() to zero out the derived key, so it's not
left hanging around in memory. This implies that when a user logs
out, it is important to first revoke the key, and then unlink it,
and then finally, to use "echo 3 > /proc/sys/vm/drop_caches" to
release any decrypted pages and dcache entries from the system
caches.
6) All this, and we also shrink the number of lines of code by around
100. :-)
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Use struct ext4_encryption_key only for the master key passed via the
kernel keyring.
For internal kernel space users, we now use struct ext4_crypt_info.
This will allow us to put information from the policy structure so we
can cache it and avoid needing to constantly looking up the extended
attribute. We will do this in a spearate patch. This patch is mostly
mechnical to make it easier for patch review.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Encrypt the filename as soon it is passed in by the user. This avoids
our needing to encrypt the filename 2 or 3 times while in the process
of creating a filename.
Similarly, when looking up a directory entry, encrypt the filename
early, or if the encryption key is not available, base-64 decode the
file syystem so that the hash value and the last 16 bytes of the
encrypted filename is available in the new struct ext4_filename data
structure.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The ext4_extent_tree_init() function hasn't been in the ext4 code for
a long time ago, except in an unused function prototype in ext4.h
Google-Bug-Id: 4530137
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
for ext4 encryption which provide better security and performance.
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Merge tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Some miscellaneous bug fixes and some final on-disk and ABI changes
for ext4 encryption which provide better security and performance"
* tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix growing of tiny filesystems
ext4: move check under lock scope to close a race.
ext4: fix data corruption caused by unwritten and delayed extents
ext4 crypto: remove duplicated encryption mode definitions
ext4 crypto: do not select from EXT4_FS_ENCRYPTION
ext4 crypto: add padding to filenames before encrypting
ext4 crypto: simplify and speed up filename encryption
This patch removes duplicated encryption modes which were already in
ext4.h. They were duplicated from commit 3edc18d and commit f542fb.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Michael Halcrow <mhalcrow@google.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This obscures the length of the filenames, to decrease the amount of
information leakage. By default, we pad the filenames to the next 4
byte boundaries. This costs nothing, since the directory entries are
aligned to 4 byte boundaries anyway. Filenames can also be padded to
8, 16, or 32 bytes, which will consume more directory space.
Change-Id: Ibb7a0fb76d2c48e2061240a709358ff40b14f322
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Avoid using SHA-1 when calculating the user-visible filename when the
encryption key is available, and avoid decrypting lots of filenames
when searching for a directory entry in a directory block.
Change-Id: If4655f144784978ba0305b597bfa1c8d7bb69e63
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Pull third hunk of vfs changes from Al Viro:
"This contains the ->direct_IO() changes from Omar + saner
generic_write_checks() + dealing with fcntl()/{read,write}() races
(mirroring O_APPEND/O_DIRECT into iocb->ki_flags and instead of
repeatedly looking at ->f_flags, which can be changed by fcntl(2),
check ->ki_flags - which cannot) + infrastructure bits for dhowells'
d_inode annotations + Christophs switch of /dev/loop to
vfs_iter_write()"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (30 commits)
block: loop: switch to VFS ITER_BVEC
configfs: Fix inconsistent use of file_inode() vs file->f_path.dentry->d_inode
VFS: Make pathwalk use d_is_reg() rather than S_ISREG()
VFS: Fix up debugfs to use d_is_dir() in place of S_ISDIR()
VFS: Combine inode checks with d_is_negative() and d_is_positive() in pathwalk
NFS: Don't use d_inode as a variable name
VFS: Impose ordering on accesses of d_inode and d_flags
VFS: Add owner-filesystem positive/negative dentry checks
nfs: generic_write_checks() shouldn't be done on swapout...
ocfs2: use __generic_file_write_iter()
mirror O_APPEND and O_DIRECT into iocb->ki_flags
switch generic_write_checks() to iocb and iter
ocfs2: move generic_write_checks() before the alignment checks
ocfs2_file_write_iter: stop messing with ppos
udf_file_write_iter: reorder and simplify
fuse: ->direct_IO() doesn't need generic_write_checks()
ext4_file_write_iter: move generic_write_checks() up
xfs_file_aio_write_checks: switch to iocb/iov_iter
generic_write_checks(): drop isblk argument
blkdev_write_iter: expand generic_file_checks() call in there
...
Also add the test dummy encryption mode flag so we can more easily
test the encryption patches using xfstests.
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The original dax patchset split the ext2/4_file_operations because of the
two NULL splice_read/splice_write in the dax case.
In the vfs if splice_read/splice_write are NULL we then call
default_splice_read/write.
What we do here is make generic_file_splice_read aware of IS_DAX() so the
original ext2/4_file_operations can be used as is.
For write it appears that iter_file_splice_write is just fine. It uses
the regular f_op->write(file,..) or new_sync_write(file, ...).
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For encrypted directories, we need to pass in a separate parameter for
the decrypted filename, since the directory entry contains the
encrypted filename.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
On encrypt, we will re-assign the buffer_heads to point to a bounce
page rather than the control_page (which is the original page to write
that contains the plaintext). The block I/O occurs against the bounce
page. On write completion, we re-assign the buffer_heads to the
original plaintext page.
On decrypt, we will attach a read completion callback to the bio
struct. This read completion will decrypt the read contents in-place
prior to setting the page up-to-date.
The current encryption mode, AES-256-XTS, lacks cryptographic
integrity. AES-256-GCM is in-plan, but we will need to devise a
mechanism for handling the integrity data.
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The rw parameter to direct_IO is redundant with iov_iter->type, and
treated slightly differently just about everywhere it's used: some users
do rw & WRITE, and others do rw == WRITE where they should be doing a
bitwise check. Simplify this with the new iov_iter_rw() helper, which
always returns either READ or WRITE.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This takes code from fs/mpage.c and optimizes it for ext4. Its
primary reason is to allow us to more easily add encryption to ext4's
read path in an efficient manner.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
and read-only images (for which the implementation is mostly just the
reserved code point for a read-only feature :-)
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"Ext4 bug fixes.
We also reserved code points for encryption and read-only images (for
which the implementation is mostly just the reserved code point for a
read-only feature :-)"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix indirect punch hole corruption
ext4: ignore journal checksum on remount; don't fail
ext4: remove duplicate remount check for JOURNAL_CHECKSUM change
ext4: fix mmap data corruption in nodelalloc mode when blocksize < pagesize
ext4: support read-only images
ext4: change to use setup_timer() instead of init_timer()
ext4: reserve codepoints used by the ext4 encryption feature
jbd2: complain about descriptor block checksum errors
