For now ,we use ext4_punch_hole() during fast commit replay delete range
procedure. But it will be affected by inode->i_size, which may not
correct during fast commit replay procedure. The following test will
failed.

-create & write foo (len 1000K)
-falloc FALLOC_FL_ZERO_RANGE foo (range 400K - 600K)
-create & fsync bar
-falloc FALLOC_FL_PUNCH_HOLE foo (range 300K-500K)
-fsync foo
-crash before a full commit

After the fast_commit reply procedure, the range 400K-500K will not be
removed. Because in this case, when calling ext4_punch_hole() the
inode->i_size is 0, and it just retruns with doing nothing.

Change to use ext4_ext_remove_space() instead of ext4_punch_hole()
to remove blocks of inode directly.
Signed-off-by: NXin Yin <yinxin.x@bytedance.com>
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223032337.5198-2-yinxin.x@bytedance.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

This series takes care of a couple of TODOs and adds new ones. Update
the TODOs section to reflect current state and future work that needs
to happen.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-5-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Move fast commit stats updating logic to a separate function from
ext4_fc_commit(). This significantly improves readability of
ext4_fc_commit().
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-4-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch drops ext4_fc_start_ineligible() and
ext4_fc_stop_ineligible() APIs. Fast commit ineligible transactions
should simply call ext4_fc_mark_ineligible() after starting the
trasaction.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-3-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Since there are no blocks in an inline data inode, there's no point in
fixing iblocks field in fast commit replay path for this inode.
Similarly, there's no point in fixing any block bitmaps / global block
counters with respect to such an inode. Just bail out from these
functions if an inline data inode is encountered.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211015182513.395917-2-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

During the commit phase in fast commits if an inode with inline data
is being committed, also commit the inline data along with
inode. Since recovery code just blindly copies entire content found in
inode TLV, there is no change needed on the recovery path. Thus, this
change is backward compatiable.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211015182513.395917-1-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Now EXT4_FC_TAG_ADD_RANGE uses ext4_extent to track the
newly-added blocks, but the limit on the max value of
ee_len field is ignored, and it can lead to BUG_ON as
shown below when running command "fallocate -l 128M file"
on a fast_commit-enabled fs:

  kernel BUG at fs/ext4/ext4_extents.h:199!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 3 PID: 624 Comm: fallocate Not tainted 5.14.0-rc6+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
  RIP: 0010:ext4_fc_write_inode_data+0x1f3/0x200
  Call Trace:
   ? ext4_fc_write_inode+0xf2/0x150
   ext4_fc_commit+0x93b/0xa00
   ? ext4_fallocate+0x1ad/0x10d0
   ext4_sync_file+0x157/0x340
   ? ext4_sync_file+0x157/0x340
   vfs_fsync_range+0x49/0x80
   do_fsync+0x3d/0x70
   __x64_sys_fsync+0x14/0x20
   do_syscall_64+0x3b/0xc0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Simply fixing it by limiting the number of blocks
in one EXT4_FC_TAG_ADD_RANGE TLV.

Fixes: aa75f4d3 ("ext4: main fast-commit commit path")
Cc: stable@kernel.org
Signed-off-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210820044505.474318-1-houtao1@huawei.com

Let's pass fc_dentry directly since those arguments (tag, parent_ino and
ino etc) can be deferenced from it.
Signed-off-by: NGuoqing Jiang <jiangguoqing@kylinos.cn>
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210727080708.3708814-1-guoqing.jiang@linux.dev

Fast commit recovery data on disk may not be aligned. So, when the
recovery code reads it, this patch makes sure that fast commit info
found on-disk is first memcpy-ed into an aligned variable before
accessing it. As a consequence of it, we also remove some macros that
could resulted in unaligned accesses.

Cc: stable@kernel.org
Fixes: 8016e29f ("ext4: fast commit recovery path")
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210519215920.2037527-1-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Using no_printk() for jbd_debug() revealed two warnings:

fs/jbd2/recovery.c: In function 'fc_do_one_pass':
fs/jbd2/recovery.c:256:30: error: format '%d' expects a matching 'int' argument [-Werror=format=]
  256 |                 jbd_debug(3, "Processing fast commit blk with seq %d");
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/ext4/fast_commit.c: In function 'ext4_fc_replay_add_range':
fs/ext4/fast_commit.c:1732:30: error: format '%d' expects argument of type 'int', but argument 2 has type 'long unsigned int' [-Werror=format=]
 1732 |                 jbd_debug(1, "Converting from %d to %d %lld",

The first one was added incorrectly, and was also missing a few newlines
in debug output, and the second one happened when the type of an
argument changed.
Reported-by: Nkernel test robot <lkp@intel.com>
Fixes: d5564351 ("jbd2: avoid -Wempty-body warnings")
Fixes: 6db07461 ("ext4: use BIT() macro for BH_** state bits")
Fixes: 5b849b5f ("jbd2: fast commit recovery path")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210409201211.1866633-1-arnd@kernel.orgSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Signed-off-by: NBhaskar Chowdhury <unixbhaskar@gmail.com>
Link: https://lore.kernel.org/r/cover.1616840203.git.unixbhaskar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

In case of if not ext4_fc_add_tlv branch, an error return code is missing.

Cc: stable@kernel.org
Fixes: aa75f4d3 ("ext4: main fast-commit commit path")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NXu Yihang <xuyihang@huawei.com>
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210408070033.123047-1-xuyihang@huawei.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch adds rename whiteout support in fast commits. Note that the
whiteout object that gets created is actually char device. Which
imples, the function ext4_inode_journal_mode(struct inode *inode)
would return "JOURNAL_DATA" for this inode. This has a consequence in
fast commit code that it will make creation of the whiteout object a
fast-commit ineligible behavior and thus will fall back to full
commits. With this patch, this can be observed by running fast commits
with rename whiteout and seeing the stats generated by ext4_fc_stats
tracepoint as follows:

ext4_fc_stats: dev 254:32 fc ineligible reasons:
XATTR:0, CROSS_RENAME:0, JOURNAL_FLAG_CHANGE:0, NO_MEM:0, SWAP_BOOT:0,
RESIZE:0, RENAME_DIR:0, FALLOC_RANGE:0, INODE_JOURNAL_DATA:16;
num_commits:6, ineligible: 6, numblks: 3

So in short, this patch guarantees that in case of rename whiteout, we
fall back to full commits.

Amir mentioned that instead of creating a new whiteout object for
every rename, we can create a static whiteout object with irrelevant
nlink. That will make fast commits to not fall back to full
commit. But until this happens, this patch will ensure correctness by
falling back to full commits.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Cc: stable@kernel.org
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210316221921.1124955-1-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

In the fast_commit.c, list_for_each* + list_entry can be changed to
list_for_each_entry*. It reduces number of variables and lines.
Signed-off-by: NDaejun Park <daejun7.park@samsung.com>
Link: https://lore.kernel.org/r/20210111013726epcms2p4579ae56040d7043db785bf0d0a785dc7@epcms2p4Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

There is no point in allocating memory for a synchronous flush.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In the fast commit, it adds REQ_FUA and REQ_PREFLUSH on each fast
commit block when barrier is enabled.  However, in recovery phase,
ext4 compares CRC value in the tail.  So it is sufficient to add
REQ_FUA and REQ_PREFLUSH on the block that has tail.
Signed-off-by: NDaejun Park <daejun7.park@samsung.com>
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20210106013242epcms2p5b6b4ed8ca86f29456fdf56aa580e74b4@epcms2p5Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

After full/fast commit, entries in staging queue are promoted to main
queue. In ext4_fs_cleanup function, it splice to staging queue to
staging queue.

Fixes: aa75f4d3 ("ext4: main fast-commit commit path")
Signed-off-by: NDaejun Park <daejun7.park@samsung.com>
Reviewed-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201230094851epcms2p6eeead8cc984379b37b2efd21af90fd1a@epcms2p6Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

1: ext4_iget/ext4_find_extent never returns NULL, use IS_ERR
instead of IS_ERR_OR_NULL to fix this.

2: ext4_fc_replay_inode should set the inode to NULL when IS_ERR.
and go to call iput properly.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Signed-off-by: NYi Li <yili@winhong.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201230033827.3996064-1-yili@winhong.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

This patch makes fast_commit.h byte by byte identical with
e2fsprogs/fast_commit.h. This will help us ensure that there are no
on-disk format inconsistencies between e2fsck and kernel ext4.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201120202232.2240293-1-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Fast commit on-disk format is designed such that the replay of these
tags can be idempotent. This patch adds documentation in the code in
form of comments and in form kernel docs that describes these
characteristics. This patch also adds a TODO item needed to ensure
kernel fast commit replay idempotence.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201119232822.1860882-1-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Add missing __acquire() and __releases() annotations, and make
fc_ineligible_reasons[] static, as it is not used outside of
fs/ext4/fast_commit.c.
Signed-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>

If the journal dev is different from fsdev, issue a cache flush before
committing fast commit blocks to disk.
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/20201106035911.1942128-20-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>

In case of fast commits, determine if the inode is dirty by checking
if the inode is on fast commit list. This also helps us get rid of
ext4_inode_info.i_fc_committed_subtid field.
Reported-by: NAndrea Righi <andrea.righi@canonical.com>
Tested-by: NAndrea Righi <andrea.righi@canonical.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-18-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Mark the fast commit buffer as dirty before submission.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-16-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Add a TODO to remember fixing REQ_FUA | REQ_PREFLUSH for fast commit
buffers. Also, fix a typo in top level comment in fast_commit.c
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-15-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This patch removes the deduplicates the code that implements waiting
on inode that's being committed. That code is moved into a new
function.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-14-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

In jbd2_fc_end_commit_fallback(), we know which tid to commit. There's
no need for caller to pass it.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-10-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>

Firstly, pass handle to all ext4_fc_track_* functions and use
transaction id found in handle->h_transaction->h_tid for tracking fast
commit updates. Secondly, don't pass inode to
ext4_fc_track_link/create/unlink functions. inode can be found inside
these functions as d_inode(dentry). However, rename path is an
exeception. That's because in that case, we need inode that's not same
as d_inode(dentry). To handle that, add a couple of low-level wrapper
functions that take inode and dentry as arguments.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-5-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

If inode gets evicted due to memory pressure, we have to remove it
from the fast commit list. However, that inode may have uncommitted
changes that fast commits will lose. So, just fall back to full
commits in this case. Also, rename the fast commit ineligiblity reason
from "EXT4_FC_REASON_MEM" to "EXT4_FC_REASON_MEM_NOMEM" for better
expression.
Suggested-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201106035911.1942128-3-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

With this fix, fast commit recovery code uses IS_ERR() for path
returned by ext4_find_extent.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027204342.2794949-1-harshadshirwadkar@gmail.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 patch reserves a field in the jbd2 superblock for number of fast
commit blocks. When this value is non-zero, Ext4 uses this field to
set the number of fast commit blocks.

Fixes: 6866d7b3 ("ext4/jbd2: add fast commit initialization")
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-2-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

Fixed double locking of sbi->s_fc_lock in the above function
as reported by kernel-test-robot.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201023161339.1449437-1-harshadshirwadkar@gmail.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>

This commit adds a file in procfs that tracks fast commit related
statistics.

root@kvm-xfstests:/mnt# cat /proc/fs/ext4/vdc/fc_info
fc stats:
7772 commits
15 ineligible
4083 numblks
2242us avg_commit_time
Ineligible reasons:
"Extended attributes changed":  0
"Cross rename": 0
"Journal flag changed": 0
"Insufficient memory":  0
"Swap boot":    0
"Resize":       0
"Dir renamed":  0
"Falloc range op":      0
"FC Commit Failed":     15
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-10-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 fast commit recovery support in JBD2.
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201015203802.3597742-7-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>