kernel/git/stable/linux.git/fs/jbd2/commit.c, branch linux-5.18.y

jbd2: fix outstanding credits assert in jbd2_journal_commit_transaction()

2022-08-17T12:41:57+00:00

[ Upstream commit a89573ce4ad32f19f43ec669771726817e185be0 ] 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 Signed-off-by: Sasha Levin

jbd2: fix a potential race while discarding reserved buffers after an abort

2022-04-21T18:21:30+00:00

we got issue as follows: [ 72.796117] EXT4-fs error (device sda): ext4_journal_check_start:83: comm fallocate: Detected aborted journal [ 72.826847] EXT4-fs (sda): Remounting filesystem read-only fallocate: fallocate failed: Read-only file system [ 74.791830] jbd2_journal_commit_transaction: jh=0xffff9cfefe725d90 bh=0x0000000000000000 end delay [ 74.793597] ------------[ cut here ]------------ [ 74.794203] kernel BUG at fs/jbd2/transaction.c:2063! [ 74.794886] invalid opcode: 0000 [#1] PREEMPT SMP PTI [ 74.795533] CPU: 4 PID: 2260 Comm: jbd2/sda-8 Not tainted 5.17.0-rc8-next-20220315-dirty #150 [ 74.798327] RIP: 0010:__jbd2_journal_unfile_buffer+0x3e/0x60 [ 74.801971] RSP: 0018:ffffa828c24a3cb8 EFLAGS: 00010202 [ 74.802694] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 74.803601] RDX: 0000000000000001 RSI: ffff9cfefe725d90 RDI: ffff9cfefe725d90 [ 74.804554] RBP: ffff9cfefe725d90 R08: 0000000000000000 R09: ffffa828c24a3b20 [ 74.805471] R10: 0000000000000001 R11: 0000000000000001 R12: ffff9cfefe725d90 [ 74.806385] R13: ffff9cfefe725d98 R14: 0000000000000000 R15: ffff9cfe833a4d00 [ 74.807301] FS: 0000000000000000(0000) GS:ffff9d01afb00000(0000) knlGS:0000000000000000 [ 74.808338] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 74.809084] CR2: 00007f2b81bf4000 CR3: 0000000100056000 CR4: 00000000000006e0 [ 74.810047] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 74.810981] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 74.811897] Call Trace: [ 74.812241] [ 74.812566] __jbd2_journal_refile_buffer+0x12f/0x180 [ 74.813246] jbd2_journal_refile_buffer+0x4c/0xa0 [ 74.813869] jbd2_journal_commit_transaction.cold+0xa1/0x148 [ 74.817550] kjournald2+0xf8/0x3e0 [ 74.819056] kthread+0x153/0x1c0 [ 74.819963] ret_from_fork+0x22/0x30 Above issue may happen as follows: write truncate kjournald2 generic_perform_write ext4_write_begin ext4_walk_page_buffers do_journal_get_write_access ->add BJ_Reserved list ext4_journalled_write_end ext4_walk_page_buffers write_end_fn ext4_handle_dirty_metadata ***************JBD2 ABORT************** jbd2_journal_dirty_metadata -> return -EROFS, jh in reserved_list jbd2_journal_commit_transaction while (commit_transaction->t_reserved_list) jh = commit_transaction->t_reserved_list; truncate_pagecache_range do_invalidatepage ext4_journalled_invalidatepage jbd2_journal_invalidatepage journal_unmap_buffer __dispose_buffer __jbd2_journal_unfile_buffer jbd2_journal_put_journal_head ->put last ref_count __journal_remove_journal_head bh->b_private = NULL; jh->b_bh = NULL; jbd2_journal_refile_buffer(journal, jh); bh = jh2bh(jh); ->bh is NULL, later will trigger null-ptr-deref journal_free_journal_head(jh); After commit 96f1e0974575, we no longer hold the j_state_lock while iterating over the list of reserved handles in jbd2_journal_commit_transaction(). This potentially allows the journal_head to be freed by journal_unmap_buffer while the commit codepath is also trying to free the BJ_Reserved buffers. Keeping j_state_lock held while trying extends hold time of the lock minimally, and solves this issue. Fixes: 96f1e0974575("jbd2: avoid long hold times of j_state_lock while committing a transaction") Signed-off-by: Ye Bin Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220317142137.1821590-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o

jbd2: refactor wait logic for transaction updates into a common function

2022-02-03T15:57:44+00:00

No functionality change as such in this patch. This only refactors the common piece of code which waits for t_updates to finish into a common function named as jbd2_journal_wait_updates(journal_t *) Signed-off-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/8c564f70f4b2591171677a2a74fccb22a7b6c3a4.1642416995.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o

ext4: fast commit may not fallback for ineligible commit

2022-02-03T15:56:39+00:00

For the follow scenario: 1. jbd start commit transaction n 2. task A get new handle for transaction n+1 3. task A do some ineligible actions and mark FC_INELIGIBLE 4. jbd complete transaction n and clean FC_INELIGIBLE 5. task A call fsync In this case fast commit will not fallback to full commit and transaction n+1 also not handled by jbd. Make ext4_fc_mark_ineligible() also record transaction tid for latest ineligible case, when call ext4_fc_cleanup() check current transaction tid, if small than latest ineligible tid do not clear the EXT4_MF_FC_INELIGIBLE. Reported-by: kernel test robot Reported-by: Dan Carpenter Reported-by: Ritesh Harjani Suggested-by: Harshad Shirwadkar Signed-off-by: Xin Yin Link: https://lore.kernel.org/r/20220117093655.35160-2-yinxin.x@bytedance.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

block: use an on-stack bio in blkdev_issue_flush

2021-01-27T16:51:48+00:00

There is no point in allocating memory for a synchronous flush. Signed-off-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Chaitanya Kulkarni Acked-by: Damien Le Moal Signed-off-by: Jens Axboe

jbd2: add todo for a fast commit performance optimization

2020-11-07T04:01:03+00:00

Fast commit performance can be optimized if commit thread doesn't wait for ongoing fast commits to complete until the transaction enters T_FLUSH state. Document this optimization. Suggested-by: Jan Kara Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201106035911.1942128-11-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

jbd2: rename j_maxlen to j_total_len and add jbd2_journal_max_txn_bufs

2020-11-07T04:01:02+00:00

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: Jan Kara Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201106035911.1942128-6-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

jbd2: add fast commit machinery

2020-10-22T03:22:37+00:00

This functions adds necessary APIs needed in JBD2 layer for fast commits. Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201015203802.3597742-5-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

jbd2, ext4, ocfs2: introduce/use journal callbacks j_submit|finish_inode_data_buffers()

2020-10-18T14:37:15+00:00

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: Mauricio Faria de Oliveira Suggested-by: Jan Kara Reviewed-by: Jan Kara Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20201006004841.600488-3-mfo@canonical.com Signed-off-by: Theodore Ts'o

jbd2: introduce/export functions jbd2_journal_submit|finish_inode_data_buffers()

2020-10-18T14:37:15+00:00

Export functions that implement the current behavior done for an inode in journal_submit|finish_inode_data_buffers(). No functional change. Signed-off-by: Mauricio Faria de Oliveira Suggested-by: Jan Kara Reviewed-by: Jan Kara Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20201006004841.600488-2-mfo@canonical.com Signed-off-by: Theodore Ts'o