The patch titled Subject: ocfs2: fix DIO failure due to insufficient transaction credits has been added to the -mm mm-hotfixes-unstable branch. Its filename is ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Jan Kara jack@suse.cz Subject: ocfs2: fix DIO failure due to insufficient transaction credits Date: Fri, 14 Jun 2024 16:52:43 +0200

The code in ocfs2_dio_end_io_write() estimates number of necessary transaction credits using ocfs2_calc_extend_credits(). This however does not take into account that the IO could be arbitrarily large and can contain arbitrary number of extents.

Extent tree manipulations do often extend the current transaction but not in all of the cases. For example if we have only single block extents in the tree, ocfs2_mark_extent_written() will end up calling ocfs2_replace_extent_rec() all the time and we will never extend the current transaction and eventually exhaust all the transaction credits if the IO contains many single block extents. Once that happens a WARN_ON(jbd2_handle_buffer_credits(handle) <= 0) is triggered in jbd2_journal_dirty_metadata() and subsequently OCFS2 aborts in response to this error. This was actually triggered by one of our customers on a heavily fragmented OCFS2 filesystem.

To fix the issue make sure the transaction always has enough credits for one extent insert before each call of ocfs2_mark_extent_written().

Link: https://lkml.kernel.org/r/20240617095543.6971-1-jack@suse.cz Link: https://lkml.kernel.org/r/20240614145243.8837-1-jack@suse.cz Fixes: c15471f79506 ("ocfs2: fix sparse file & data ordering issue in direct io") Signed-off-by: Jan Kara jack@suse.cz Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Reviewed-by: Heming Zhao heming.zhao@suse.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Gang He ghe@suse.com Cc: Jun Piao piaojun@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/ocfs2/aops.c | 5 +++++ fs/ocfs2/journal.c | 17 +++++++++++++++++ fs/ocfs2/journal.h | 2 ++ fs/ocfs2/ocfs2_trace.h | 2 ++ 4 files changed, 26 insertions(+)

--- a/fs/ocfs2/aops.c~ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits +++ a/fs/ocfs2/aops.c @@ -2366,6 +2366,11 @@ static int ocfs2_dio_end_io_write(struct }

list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) { + ret = ocfs2_assure_trans_credits(handle, credits); + if (ret < 0) { + mlog_errno(ret); + break; + } ret = ocfs2_mark_extent_written(inode, &et, handle, ue->ue_cpos, 1, ue->ue_phys, --- a/fs/ocfs2/journal.c~ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits +++ a/fs/ocfs2/journal.c @@ -446,6 +446,23 @@ bail: }

/* + * Make sure handle has at least 'nblocks' credits available. If it does not + * have that many credits available, we will try to extend the handle to have + * enough credits. If that fails, we will restart transaction to have enough + * credits. Similar notes regarding data consistency and locking implications + * as for ocfs2_extend_trans() apply here. + */ +int ocfs2_assure_trans_credits(handle_t *handle, int nblocks) +{ + int old_nblks = jbd2_handle_buffer_credits(handle); + + trace_ocfs2_assure_trans_credits(old_nblks); + if (old_nblks >= nblocks) + return 0; + return ocfs2_extend_trans(handle, nblocks - old_nblks); +} + +/* * If we have fewer than thresh credits, extend by OCFS2_MAX_TRANS_DATA. * If that fails, restart the transaction & regain write access for the * buffer head which is used for metadata modifications. --- a/fs/ocfs2/journal.h~ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits +++ a/fs/ocfs2/journal.h @@ -243,6 +243,8 @@ handle_t *ocfs2_start_trans(struct int ocfs2_commit_trans(struct ocfs2_super *osb, handle_t *handle); int ocfs2_extend_trans(handle_t *handle, int nblocks); +int ocfs2_assure_trans_credits(handle_t *handle, + int nblocks); int ocfs2_allocate_extend_trans(handle_t *handle, int thresh);

--- a/fs/ocfs2/ocfs2_trace.h~ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits +++ a/fs/ocfs2/ocfs2_trace.h @@ -2577,6 +2577,8 @@ DEFINE_OCFS2_ULL_UINT_EVENT(ocfs2_commit

DEFINE_OCFS2_INT_INT_EVENT(ocfs2_extend_trans);

+DEFINE_OCFS2_INT_EVENT(ocfs2_assure_trans_credits); + DEFINE_OCFS2_INT_EVENT(ocfs2_extend_trans_restart);

DEFINE_OCFS2_INT_INT_EVENT(ocfs2_allocate_extend_trans); _

Patches currently in -mm which might be from jack@suse.cz are

ocfs2-fix-dio-failure-due-to-insufficient-transaction-credits.patch