mainline inclusion
from mainline-v5.11-rc4
commit 2d01ddc8
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

If journalling is still working at the moment we get to writing error
information to the superblock we cannot write directly to the superblock
as such write could race with journalled update of the superblock and
cause journal checksum failures, writing inconsistent information to the
journal or other problems. We cannot journal the superblock directly
from the error handling functions as we are running in uncertain context
and could deadlock so just punt journalled superblock update to a
workqueue.
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-5-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc4
commit 05c2c00f
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

Protect all superblock modifications (including checksum computation)
with a superblock buffer lock. That way we are sure computed checksum
matches current superblock contents (a mismatch could cause checksum
failures in nojournal mode or if an unjournalled superblock update races
with a journalled one). Also we avoid modifying superblock contents
while it is being written out (which can cause DIF/DIX failures if we
are running in nojournal mode).
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-4-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

conflicts:
fs/ext4/file.c
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc4
commit 4392fbc4
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

Everybody passes 1 as sync argument of ext4_commit_super(). Just drop
it.
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-3-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc4
commit e789ca0c
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

save_error_info() is always called together with ext4_handle_error().
Combine them into a single call and move unconditional bits out of
save_error_info() into ext4_handle_error().
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-2-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc1
commit c92dc856
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

When filesystem inconsistency is detected with group locked, we
currently try to modify superblock to store error there without
blocking. However this can cause superblock checksum failures (or
DIF/DIX failure) when the superblock is just being written out.

Make error handling code just store error information in ext4_sb_info
structure and copy it to on-disk superblock only in ext4_commit_super().
In case of error happening with group locked, we just postpone the
superblock flushing to a workqueue.

[ Added fixup so that s_first_error_* does not get updated after
  the file system is remounted.
  Also added fix for syzbot failure.  - Ted ]
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201127113405.26867-8-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: Hillf Danton <hdanton@sina.com>
Reported-by: syzbot+9043030c040ce1849a60@syzkaller.appspotmail.com
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc1
commit 02a7780e
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

We convert errno's to ext4 on-disk format error codes in
save_error_info(). Add a function and a bit of macro magic to make this
simpler.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201127113405.26867-7-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc1
commit 40676623
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

Just move error info related functions in super.c close to
ext4_handle_error(). We'll want to combine save_error_info() with
ext4_handle_error() and this makes change more obvious and saves a
forward declaration as well. No functional change.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201127113405.26867-6-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc1
commit 014c9caa
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

The only difference between __ext4_abort() and __ext4_error() is that
the former one ignores errors=continue mount option. Unify the code to
reduce duplication.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201127113405.26867-5-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mainline inclusion
from mainline-v5.11-rc1
commit 81414b4d
category: bugfix
bugzilla: 50839
CVE: NA

-----------------------------------------------

Superblock is written out either through ext4_commit_super() or through
ext4_handle_dirty_super(). In both cases we recompute the checksum so it
is not necessary to recompute it after updating superblock free inodes &
blocks counters.
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201127113405.26867-3-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NYe Bin <yebin10@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.24
commit 64578f9417e1e3482f3e4492496772fca130f526
bugzilla: 51348

--------------------------------

[ Upstream commit 027f14f5 ]

If we try to make any changes via the journal between when the journal
is initialized, but before the multi-block allocated is initialized,
we will end up deferencing a NULL pointer when the journal commit
callback function calls ext4_process_freed_data().

The proximate cause of this failure was commit 2d01ddc8 ("ext4:
save error info to sb through journal if available") since file system
corruption problems detected before the call to ext4_mb_init() would
result in a journal commit before we aborted the mount of the file
system.... and we would then trigger the NULL pointer deref.

Link: https://lore.kernel.org/r/YAm8qH/0oo2ofSMR@mit.eduReported-by: NMurphy Zhou <jencce.kernel@gmail.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: N  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

stable inclusion
from stable-5.10.5
commit 721972b8665f784f6d840d9ef563a8971565c569
bugzilla: 46931

--------------------------------

commit c9200760 upstream.

Check for valid block size directly by validating s_log_block_size; we
were doing this in two places.  First, by calculating blocksize via
BLOCK_SIZE << s_log_block_size, and then checking that the blocksize
was valid.  And then secondly, by checking s_log_block_size directly.

The first check is not reliable, and can trigger an UBSAN warning if
s_log_block_size on a maliciously corrupted superblock is greater than
22.  This is harmless, since the second test will correctly reject the
maliciously fuzzed file system, but to make syzbot shut up, and
because the two checks are duplicative in any case, delete the
blocksize check, and move the s_log_block_size earlier in
ext4_fill_super().
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reported-by: syzbot+345b75652b1d24227443@syzkaller.appspotmail.com
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

stable inclusion
from stable-5.10.4
commit 0b3ade0b86865046ea07173011372cc9c5874773
bugzilla: 46903

--------------------------------

commit b08070ec upstream.

ext4_handle_error() with errors=continue mount option can accidentally
remount the filesystem read-only when the system is rebooting. Fix that.

Fixes: 1dc1097f ("ext4: avoid panic during forced reboot")
Signed-off-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20201127113405.26867-2-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

The options in /proc/mounts must be valid mount options --- and
fast_commit is not a mount option.  Otherwise, command sequences like
this will fail:

    # mount /dev/vdc /vdc
    # mkdir -p /vdc/phoronix_test_suite /pts
    # mount --bind /vdc/phoronix_test_suite /pts
    # mount -o remount,nodioread_nolock /pts
    mount: /pts: mount point not mounted or bad option.

And in the system logs, you'll find:

    EXT4-fs (vdc): Unrecognized mount option "fast_commit" or missing value

Fixes: 995a3ed6 ("ext4: add fast_commit feature and handling for extended mount options")
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This reverts commit acaa5326 which can
result in a ext4_superblock_csum_set() trying to sleep while a
spinlock is being held.

For more discussion of this issue, please see:

https://lore.kernel.org/r/000000000000f50cb705b313ed70@google.com

Reported-by: syzbot+7a4ba6a239b91a126c28@syzkaller.appspotmail.com
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Drop no_fc mount option that disable fast commit even if it was
enabled at mkfs time. Move fc_debug_force mount option under ifdef
EXT4_DEBUG to annotate that this is strictly for debugging and testing
purposes and should not be used in production.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-23-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Fast commit file system states are recorded in
sbi->s_mount_flags. Fast commit expects these bit manipulations to be
atomic. This patch adds helpers to make those modifications atomic.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-21-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Fast commits don't work with data journalling. This patch disables the
fast commit support when data journalling is turned on.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201106035911.1942128-19-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch removes jbd2_fc_init() API and its related functions to
simplify enabling fast commits. With this change, the number of fast
commit blocks to use is solely determined by the JBD2 layer. So, we
move the default value for minimum number of fast commit blocks from
ext4/fast_commit.h to include/linux/jbd2.h. However, whether or not to
use fast commits is determined by the file system. The file system
just sets the fast commit feature using
jbd2_journal_set_features(). JBD2 layer then determines how many
blocks to use for fast commits (based on the value found in the JBD2
superblock).

Note that the JBD2 feature flag of fast commits is just an indication
that there are fast commit blocks present on disk. It doesn't tell
JBD2 layer about the intent of the file system of whether to it wants
to use fast commit or not. That's why, we blindly clear the fast
commit flag in journal_reset() after the recovery is done.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-7-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The on-disk superblock field sb->s_maxlen represents the total size of
the journal including the fast commit area and is no more the max
number of blocks available for a transaction. The maximum number of
blocks available to a transaction is reduced by the number of fast
commit blocks. So, this patch renames j_maxlen to j_total_len to
better represent its intent. Also, it adds a function to calculate max
number of bufs available for a transaction.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-6-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

ext4_fc_track_range() should only be called when blocks are added or
removed from an inode. So, the only places from where we need to call
this function are ext4_map_blocks(), punch hole, collapse / zero
range, truncate. Remove all the other redundant calls to ths function.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-4-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The macro MOPT_Q is used to indicates the mount option is related to
quota stuff and is defined to be MOPT_NOSUPPORT when CONFIG_QUOTA is
disabled.  Normally the quota options are handled explicitly, so it
didn't matter that the MOPT_STRING flag was missing, even though the
usrjquota and grpjquota mount options take a string argument.  It's
important that's present in the !CONFIG_QUOTA case, since without
MOPT_STRING, the mount option matcher will match usrjquota= followed
by an integer, and will otherwise skip the table entry, and so "mount
option not supported" error message is never reported.

[ Fixed up the commit description to better explain why the fix
  works. --TYT ]

Fixes: 26092bf5 ("ext4: use a table-driven handler for mount options")
Signed-off-by: NKaixu Xia <kaixuxia@tencent.com>
Link: https://lore.kernel.org/r/1603986396-28917-1-git-send-email-kaixuxia@tencent.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

This switches ext4 over to the generic support provided in libfs.

Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.
Signed-off-by: NDaniel Rosenberg <drosen@google.com>
Reviewed-by: NEric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20201028050820.1636571-1-drosen@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Ext4's fast commit related transient states should use
sb->s_mount_flags instead of persistent sb->s_mount_state.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-3-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This is a debug only mount option that forcefully turns fast commits
on at mount time.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-9-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch adds fast commit recovery path support for Ext4 file
system. We add several helper functions that are similar in spirit to
e2fsprogs journal recovery path handlers. Example of such functions
include - a simple block allocator, idempotent block bitmap update
function etc. Using these routines and the fast commit log in the fast
commit area, the recovery path (ext4_fc_replay()) performs fast commit
log recovery.
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-8-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch adds main fast commit commit path handlers. The overall
patch can be divided into two inter-related parts:

(A) Metadata updates tracking

    This part consists of helper functions to track changes that need
    to be committed during a commit operation. These updates are
    maintained by Ext4 in different in-memory queues. Following are
    the APIs and their short description that are implemented in this
    patch:

    - ext4_fc_track_link/unlink/creat() - Track unlink. link and creat
      operations
    - ext4_fc_track_range() - Track changed logical block offsets
      inodes
    - ext4_fc_track_inode() - Track inodes
    - ext4_fc_mark_ineligible() - Mark file system fast commit
      ineligible()
    - ext4_fc_start_update() / ext4_fc_stop_update() /
      ext4_fc_start_ineligible() / ext4_fc_stop_ineligible() These
      functions are useful for co-ordinating inode updates with
      commits.

(B) Main commit Path

    This part consists of functions to convert updates tracked in
    in-memory data structures into on-disk commits. Function
    ext4_fc_commit() is the main entry point to commit path.
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-6-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch adds fast commit area trackers in the journal_t
structure. These are initialized via the jbd2_fc_init() routine that
this patch adds. This patch also adds ext4/fast_commit.c and
ext4/fast_commit.h files for fast commit code that will be added in
subsequent patches in this series.
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-4-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

We are running out of mount option bits. Add handling for using
s_mount_opt2. Add ext4 and jbd2 fast commit feature flag and also add
ability to turn off the fast commit feature in Ext4.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-3-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

When we try to use file already used as a quota file again (for the same
or different quota type), strange things can happen. At the very least
lockdep annotations may be wrong but also inode flags may be wrongly set
/ reset. When the file is used for two quota types at once we can even
corrupt the file and likely crash the kernel. Catch all these cases by
checking whether passed file is already used as quota file and bail
early in that case.

This fixes occasional generic/219 failure due to lockdep complaint.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reported-by: NRitesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201015110330.28716-1-jack@suse.czSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This implements journal callbacks j_submit|finish_inode_data_buffers()
with different behavior for data=journal: to write-protect pages under
commit, preventing changes to buffers writeably mapped to userspace.

If a buffer's content changes between commit's checksum calculation
and write-out to disk, it can cause journal recovery/mount failures
upon a kernel crash or power loss.

    [   27.334874] EXT4-fs: Warning: mounting with data=journal disables delayed allocation, dioread_nolock, and O_DIRECT support!
    [   27.339492] JBD2: Invalid checksum recovering data block 8705 in log
    [   27.342716] JBD2: recovery failed
    [   27.343316] EXT4-fs (loop0): error loading journal
    mount: /ext4: can't read superblock on /dev/loop0.

In j_submit_inode_data_buffers() we write-protect the inode's pages
with write_cache_pages() and redirty w/ writepage callback if needed.

In j_finish_inode_data_buffers() there is nothing do to.

And in order to use the callbacks, inodes are added to the inode list
in transaction in __ext4_journalled_writepage() and ext4_page_mkwrite().

In ext4_page_mkwrite() we must make sure that the buffers are attached
to the transaction as jbddirty with write_end_fn(), as already done in
__ext4_journalled_writepage().
Signed-off-by: NMauricio Faria de Oliveira <mfo@canonical.com>
Reported-by: NDann Frazier <dann.frazier@canonical.com>
Reported-by: kernel test robot <lkp@intel.com> # wbc.nr_to_write
Suggested-by: NJan Kara <jack@suse.cz>
Reviewed-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201006004841.600488-5-mfo@canonical.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Introduce journal callbacks to allow different behaviors
for an inode in journal_submit|finish_inode_data_buffers().

The existing users of the current behavior (ext4, ocfs2)
are adapted to use the previously exported functions
that implement the current behavior.

Users are callers of jbd2_journal_inode_ranged_write|wait(),
which adds the inode to the transaction's inode list with
the JI_WRITE|WAIT_DATA flags. Only ext4 and ocfs2 in-tree.

Both CONFIG_EXT4_FS and CONFIG_OCSFS2_FS select CONFIG_JBD2,
which builds fs/jbd2/commit.c and journal.c that define and
export the functions, so we can call directly in ext4/ocfs2.
Signed-off-by: NMauricio Faria de Oliveira <mfo@canonical.com>
Suggested-by: NJan Kara <jack@suse.cz>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201006004841.600488-3-mfo@canonical.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Now we only use sb_bread_unmovable() to read superblock and descriptor
block at mount time, so there is no opportunity that we need to clear
buffer verified bit and also handle buffer write_io error bit. But for
the sake of unification, let's introduce ext4_sb_bread_unmovable() to
replace all sb_bread_unmovable(). After this patch, we stop using read
helpers in fs/buffer.c.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-8-yi.zhang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

If we readahead inode tables in __ext4_get_inode_loc(), it may bypass
buffer_write_io_error() check, so introduce ext4_sb_breadahead_unmovable()
to handle this special case.

This patch also replace sb_breadahead_unmovable() in ext4_fill_super()
for the sake of unification.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200924073337.861472-6-yi.zhang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Revome all open codes that read metadata buffers, switch to use
ext4_read_bh_*() common helpers.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Suggested-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-4-yi.zhang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The previous patch add clear_buffer_verified() before we read metadata
block from disk again, but it's rather easy to miss clearing of this bit
because currently we read metadata buffer through different open codes
(e.g. ll_rw_block(), bh_submit_read() and invoke submit_bh() directly).
So, it's time to add common helpers to unify in all the places reading
metadata buffers instead. This patch add 3 helpers:

 - ext4_read_bh_nowait(): async read metadata buffer if it's actually
   not uptodate, clear buffer_verified bit before read from disk.
 - ext4_read_bh(): sync version of read metadata buffer, it will wait
   until the read operation return and check the return status.
 - ext4_read_bh_lock(): try to lock the buffer before read buffer, it
   will skip reading if the buffer is already locked.

After this patch, we need to use these helpers in all the places reading
metadata buffer instead of different open codes.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Suggested-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-3-yi.zhang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The metadata buffer is no longer trusted after we read it from disk
again because it is not uptodate for some reasons (e.g. failed to write
back). Otherwise we may get below memory corruption problem in
ext4_ext_split()->memset() if we read stale data from the newly
allocated extent block on disk which has been failed to async write
out but miss verify again since the verified bit has already been set
on the buffer.

[   29.774674] BUG: unable to handle kernel paging request at ffff88841949d000
...
[   29.783317] Oops: 0002 [#2] SMP
[   29.784219] R10: 00000000000f4240 R11: 0000000000002e28 R12: ffff88842fa1c800
[   29.784627] CPU: 1 PID: 126 Comm: kworker/u4:3 Tainted: G      D W
[   29.785546] R13: ffffffff9cddcc20 R14: ffffffff9cddd420 R15: ffff88842fa1c2f8
[   29.786679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS ?-20190727_0738364
[   29.787588] FS:  0000000000000000(0000) GS:ffff88842fa00000(0000) knlGS:0000000000000000
[   29.789288] Workqueue: writeback wb_workfn
[   29.790319] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   29.790321]  (flush-8:0)
[   29.790844] CR2: 0000000000000008 CR3: 00000004234f2000 CR4: 00000000000006f0
[   29.791924] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   29.792839] RIP: 0010:__memset+0x24/0x30
[   29.793739] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   29.794256] Code: 90 90 90 90 90 90 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 033
[   29.795161] Kernel panic - not syncing: Fatal exception in interrupt
...
[   29.808149] Call Trace:
[   29.808475]  ext4_ext_insert_extent+0x102e/0x1be0
[   29.809085]  ext4_ext_map_blocks+0xa89/0x1bb0
[   29.809652]  ext4_map_blocks+0x290/0x8a0
[   29.809085]  ext4_ext_map_blocks+0xa89/0x1bb0
[   29.809652]  ext4_map_blocks+0x290/0x8a0
[   29.810161]  ext4_writepages+0xc85/0x17c0
...

Fix this by clearing buffer's verified bit if we read meta block from
disk again.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200924073337.861472-2-yi.zhang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Consider a situation when a filesystem was uncleanly shutdown and the
orphan list is not empty and a read-only mount is attempted. The orphan
list cleanup during mount will fail with:

ext4_check_bdev_write_error:193: comm mount: Error while async write back metadata

This happens because sbi->s_bdev_wb_err is not initialized when mounting
the filesystem in read only mode and so ext4_check_bdev_write_error()
falsely triggers.

Initialize sbi->s_bdev_wb_err unconditionally to avoid this problem.

Fixes: bc71726c ("ext4: abort the filesystem if failed to async write metadata buffer")
Cc: stable@kernel.org
Signed-off-by: NZhang Xiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200928020556.710971-1-zhangxiaoxu5@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Rename system_blks to s_system_blks inside ext4_sb_info, keep
the naming rules consistent with other variables, which is
convenient for code reading and writing.
Signed-off-by: NChunguang Xu <brookxu@tencent.com>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reviewed-by: NRitesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/1600916623-544-2-git-send-email-brookxu@tencent.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Rename journal_dev to s_journal_dev inside ext4_sb_info, keep
the naming rules consistent with other variables, which is
convenient for code reading and writing.
Signed-off-by: NChunguang Xu <brookxu@tencent.com>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reviewed-by: NRitesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/1600916623-544-1-git-send-email-brookxu@tencent.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

The race condition could cause the persisted superblock checksum
to not match the contents of the superblock, causing the
superblock to be considered corrupt.

An example of the race follows.  A first thread is interrupted in the
middle of a checksum calculation. Then, another thread changes the
superblock, calculates a new checksum, and sets it. Then, the first
thread resumes and sets the checksum based on the older superblock.

To fix, serialize the superblock checksum calculation using the buffer
header lock. While a spinlock is sufficient, the buffer header is
already there and there is precedent for locking it (e.g. in
ext4_commit_super).

Tested the patch by booting up a kernel with the patch, creating
a filesystem and some files (including some orphans), and then
unmounting and remounting the file system.

Cc: stable@kernel.org
Signed-off-by: NConstantine Sapuntzakis <costa@purestorage.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Suggested-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200914161014.22275-1-costa@purestorage.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>