[SRU][F][PATCH 1/1] ocfs2: fix DIO failure due to insufficient transaction credits
Massimiliano Pellizzer
massimiliano.pellizzer at canonical.com
Tue Oct 15 11:40:49 UTC 2024
From: Jan Kara <jack at suse.cz>
commit be346c1a6eeb49d8fda827d2a9522124c2f72f36 upstream.
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 at suse.cz>
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
Reviewed-by: Heming Zhao <heming.zhao at suse.com>
Cc: Mark Fasheh <mark at fasheh.com>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Junxiao Bi <junxiao.bi at oracle.com>
Cc: Changwei Ge <gechangwei at live.cn>
Cc: Gang He <ghe at suse.com>
Cc: Jun Piao <piaojun at huawei.com>
Cc: <stable at vger.kernel.org>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(backported from commit a68b896aa56e435506453ec8835bc991ec3ae687 linux-5.10.y)
[mpellizzer: backported using handle->h_buffer_credits instead of
jbd2_handle_buffer_credits(handle) since the latter is not defined
in focal]
CVE-2024-42077
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.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 91702ebffe84c..6b7b411f2e495 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2382,6 +2382,11 @@ 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 22e9a92ff9682..7d1b522a86306 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 = handle->h_buffer_credits;
+
+ 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 eb7a21bac71ef..bc5d77cb3c500 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -244,6 +244,8 @@ 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 dc4bce1649c1b..7a9cfd61145a0 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);
--
2.43.0
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