linux-stable.git/fs/jbd2/commit.c, branch v6.1.78

jbd2: fix soft lockup in journal_finish_inode_data_buffers()

2024-01-20T10:50:07+00:00

[ Upstream commit 6c02757c936063f0631b4e43fe156f8c8f1f351f ]

There's issue when do io test:
WARN: soft lockup - CPU#45 stuck for 11s! [jbd2/dm-2-8:4170]
CPU: 45 PID: 4170 Comm: jbd2/dm-2-8 Kdump: loaded Tainted: G  OE
Call trace:
 dump_backtrace+0x0/0x1a0
 show_stack+0x24/0x30
 dump_stack+0xb0/0x100
 watchdog_timer_fn+0x254/0x3f8
 __hrtimer_run_queues+0x11c/0x380
 hrtimer_interrupt+0xfc/0x2f8
 arch_timer_handler_phys+0x38/0x58
 handle_percpu_devid_irq+0x90/0x248
 generic_handle_irq+0x3c/0x58
 __handle_domain_irq+0x68/0xc0
 gic_handle_irq+0x90/0x320
 el1_irq+0xcc/0x180
 queued_spin_lock_slowpath+0x1d8/0x320
 jbd2_journal_commit_transaction+0x10f4/0x1c78 [jbd2]
 kjournald2+0xec/0x2f0 [jbd2]
 kthread+0x134/0x138
 ret_from_fork+0x10/0x18

Analyzed informations from vmcore as follows:
(1) There are about 5k+ jbd2_inode in 'commit_transaction->t_inode_list';
(2) Now is processing the 855th jbd2_inode;
(3) JBD2 task has TIF_NEED_RESCHED flag;
(4) There's no pags in address_space around the 855th jbd2_inode;
(5) There are some process is doing drop caches;
(6) Mounted with 'nodioread_nolock' option;
(7) 128 CPUs;

According to informations from vmcore we know 'journal->j_list_lock' spin lock
competition is fierce. So journal_finish_inode_data_buffers() maybe process
slowly. Theoretically, there is scheduling point in the filemap_fdatawait_range_keep_errors().
However, if inode's address_space has no pages which taged with PAGECACHE_TAG_WRITEBACK,
will not call cond_resched(). So may lead to soft lockup.
journal_finish_inode_data_buffers
  filemap_fdatawait_range_keep_errors
    __filemap_fdatawait_range
      while (index <= end)
        nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end, PAGECACHE_TAG_WRITEBACK);
        if (!nr_pages)
           break;    --> If 'nr_pages' is equal zero will break, then will not call cond_resched()
        for (i = 0; i < nr_pages; i++)
          wait_on_page_writeback(page);
        cond_resched();

To solve above issue, add scheduling point in the journal_finish_inode_data_buffers();

Signed-off-by: Ye Bin 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20231211112544.3879780-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

jbd2: increase the journal IO's priority

2024-01-20T10:50:06+00:00

[ Upstream commit 6a3afb6ac6dfab158ebdd4b87941178f58c8939f ]

Current jbd2 only add REQ_SYNC for descriptor block, metadata log
buffer, commit buffer and superblock buffer, the submitted IO could be
throttled by writeback throttle in block layer, that could lead to
priority inversion in some cases. The log IO looks like a kind of high
priority metadata IO, so it should not be throttled by WBT like QOS
policies in block layer, let's add REQ_SYNC | REQ_IDLE to exempt from
writeback throttle, and also add REQ_META together indicates it's a
metadata IO.

Signed-off-by: Zhang Yi 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20231129114740.2686201-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

jbd2: remove t_checkpoint_io_list

2023-08-30T14:10:58+00:00

[ Upstream commit be22255360f80d3af789daad00025171a65424a5 ]

Since t_checkpoint_io_list was stop using in jbd2_log_do_checkpoint()
now, it's time to remove the whole t_checkpoint_io_list logic.

Signed-off-by: Zhang Yi 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20230606135928.434610-3-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: 46f881b5b175 ("jbd2: fix a race when checking checkpoint buffer busy")
Signed-off-by: Sasha Levin

jbd2: wake up journal waiters in FIFO order, not LIFO

2022-10-01T03:46:52+00:00

LIFO wakeup order is unfair and sometimes leads to a journal
user not being able to get a journal handle for hundreds of
transactions in a row.

FIFO wakeup can make things more fair.

Cc: stable@kernel.org
Signed-off-by: Alexey Lyashkov 
Reviewed-by: Ritesh Harjani (IBM) 
Link: https://lore.kernel.org/r/20220907165959.1137482-1-alexey.lyashkov@gmail.com
Signed-off-by: Theodore Ts'o

jbd2: drop useless return value of submit_bh

2022-09-30T03:01:40+00:00

submit_bh always returns 0. This patch cleans up 2 of it's caller
in jbd2 to drop submit_bh's useless return value.
Once all submit_bh callers are cleaned up, we can make it's return
type as void.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Jan Kara 
Signed-off-by: Ritesh Harjani (IBM) 
Link: https://lore.kernel.org/r/e069c0539be0aec61abcdc6f6141982ec85d489d.1660788334.git.ritesh.list@gmail.com
Signed-off-by: Theodore Ts'o

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

2022-08-05T03:13:46+00:00

Pull ext4 updates from Ted Ts'o:
 "Add new ioctls to set and get the file system UUID in the ext4
  superblock and improved the performance of the online resizing of file
  systems with bigalloc enabled.

  Fixed a lot of bugs, in particular for the inline data feature,
  potential races when creating and deleting inodes with shared extended
  attribute blocks, and the handling of directory blocks which are
  corrupted"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (37 commits)
  ext4: add ioctls to get/set the ext4 superblock uuid
  ext4: avoid resizing to a partial cluster size
  ext4: reduce computation of overhead during resize
  jbd2: fix assertion 'jh->b_frozen_data == NULL' failure when journal aborted
  ext4: block range must be validated before use in ext4_mb_clear_bb()
  mbcache: automatically delete entries from cache on freeing
  mbcache: Remove mb_cache_entry_delete()
  ext2: avoid deleting xattr block that is being reused
  ext2: unindent codeblock in ext2_xattr_set()
  ext2: factor our freeing of xattr block reference
  ext4: fix race when reusing xattr blocks
  ext4: unindent codeblock in ext4_xattr_block_set()
  ext4: remove EA inode entry from mbcache on inode eviction
  mbcache: add functions to delete entry if unused
  mbcache: don't reclaim used entries
  ext4: make sure ext4_append() always allocates new block
  ext4: check if directory block is within i_size
  ext4: reflect mb_optimize_scan value in options file
  ext4: avoid remove directory when directory is corrupted
  ext4: aligned '*' in comments
  ...

jbd2: fix outstanding credits assert in jbd2_journal_commit_transaction()

2022-08-03T03:52:19+00:00

We catch an assert problem in jbd2_journal_commit_transaction() when
doing fsstress and request falut injection tests. The problem is
happened in a race condition between jbd2_journal_commit_transaction()
and ext4_end_io_end(). Firstly, ext4_writepages() writeback dirty pages
and start reserved handle, and then the journal was aborted due to some
previous metadata IO error, jbd2_journal_abort() start to commit current
running transaction, the committing procedure could be raced by
ext4_end_io_end() and lead to subtract j_reserved_credits twice from
commit_transaction->t_outstanding_credits, finally the
t_outstanding_credits is mistakenly smaller than t_nr_buffers and
trigger assert.

kjournald2           kworker

jbd2_journal_commit_transaction()
 write_unlock(&journal->j_state_lock);
 atomic_sub(j_reserved_credits, t_outstanding_credits); //sub once

     	             jbd2_journal_start_reserved()
     	              start_this_handle()  //detect aborted journal
     	              jbd2_journal_free_reserved()  //get running transaction
                       read_lock(&journal->j_state_lock)
     	                __jbd2_journal_unreserve_handle()
     	               atomic_sub(j_reserved_credits, t_outstanding_credits);
                       //sub again
                       read_unlock(&journal->j_state_lock);

 journal->j_running_transaction = NULL;
 J_ASSERT(t_nr_buffers <= t_outstanding_credits) //bomb!!!

Fix this issue by using journal->j_state_lock to protect the subtraction
in jbd2_journal_commit_transaction().

Fixes: 96f1e0974575 ("jbd2: avoid long hold times of j_state_lock while committing a transaction")
Signed-off-by: Zhang Yi 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20220611130426.2013258-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o

jbd2: rename jbd_debug() to jbd2_debug()

2022-08-03T03:52:19+00:00

The name of jbd_debug() is confusing as all functions inside jbd2 have
jbd2_ prefix. Rename jbd_debug() to jbd2_debug(). No functional changes.

Signed-off-by: Jan Kara 
Reviewed-by: Lukas Czerner 
Link: https://lore.kernel.org/r/20220608112355.4397-2-jack@suse.cz
Signed-off-by: Theodore Ts'o

fs/buffer: Combine two submit_bh() and ll_rw_block() arguments

2022-07-14T18:14:32+00:00

Both submit_bh() and ll_rw_block() accept a request operation type and
request flags as their first two arguments. Micro-optimize these two
functions by combining these first two arguments into a single argument.
This patch does not change the behavior of any of the modified code.

Cc: Alexander Viro 
Cc: Jan Kara 
Acked-by: Song Liu  (for the md changes)
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20220714180729.1065367-48-bvanassche@acm.org
Signed-off-by: Jens Axboe

fs: Change try_to_free_buffers() to take a folio

2022-05-10T03:12:34+00:00

All but two of the callers already have a folio; pass a folio into
try_to_free_buffers().  This removes the last user of cancel_dirty_page()
so remove that wrapper function too.

Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jeff Layton