From: Jan Kara jack@suse.cz

mainline inclusion from mainline-v6.10-rc6 commit be346c1a6eeb49d8fda827d2a9522124c2f72f36 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGENQ CVE: CVE-2024-42077

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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().

Heming Zhao said:

------ PANIC: "Kernel panic - not syncing: OCFS2: (device dm-1): panic forced after error"

PID: xxx TASK: xxxx CPU: 5 COMMAND: "SubmitThread-CA" #0 machine_kexec at ffffffff8c069932 #1 __crash_kexec at ffffffff8c1338fa #2 panic at ffffffff8c1d69b9 #3 ocfs2_handle_error at ffffffffc0c86c0c [ocfs2] #4 __ocfs2_abort at ffffffffc0c88387 [ocfs2] #5 ocfs2_journal_dirty at ffffffffc0c51e98 [ocfs2] #6 ocfs2_split_extent at ffffffffc0c27ea3 [ocfs2] #7 ocfs2_change_extent_flag at ffffffffc0c28053 [ocfs2] #8 ocfs2_mark_extent_written at ffffffffc0c28347 [ocfs2] #9 ocfs2_dio_end_io_write at ffffffffc0c2bef9 [ocfs2]

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 Signed-off-by: He Yujie coka.heyujie@huawei.com --- 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(+)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 6b06de78f2af..b8667311c292 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -2359,6 +2359,11 @@ static int ocfs2_dio_end_io_write(struct inode *inode, }

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, diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c index db52e843002a..ef188543c89f 100644 --- a/fs/ocfs2/journal.c +++ b/fs/ocfs2/journal.c @@ -449,6 +449,23 @@ int ocfs2_extend_trans(handle_t *handle, int nblocks) return status; }

+/* + * 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 diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h index bfe611ed1b1d..77bf7842894f 100644 --- a/fs/ocfs2/journal.h +++ b/fs/ocfs2/journal.h @@ -243,6 +243,8 @@ handle_t *ocfs2_start_trans(struct ocfs2_super *osb, 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);

diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h index dc4bce1649c1..7a9cfd61145a 100644 --- a/fs/ocfs2/ocfs2_trace.h +++ b/fs/ocfs2/ocfs2_trace.h @@ -2578,6 +2578,8 @@ DEFINE_OCFS2_ULL_UINT_EVENT(ocfs2_commit_cache_end);

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);