Backport of jbd2 commit 169f1a2a87aae44034da4b9f81be1683d33de6d0
("jbd2: use a single printk for jbd_debug()")
Quoting the original:
--------------
Since the jbd_debug() is implemented with two separate printk()
calls, it can lead to corrupted and misleading debug output like
the following (see lines marked with "*"):
[ 290.339362] (fs/jbd2/journal.c, 203): kjournald2: kjournald2 wakes
[ 290.339365] (fs/jbd2/journal.c, 155): kjournald2: commit_sequence=42103, commit_request=42104
[ 290.339369] (fs/jbd2/journal.c, 158): kjournald2: OK, requests differ
[* 290.339376] (fs/jbd2/journal.c, 648): jbd2_log_wait_commit:
[* 290.339379] (fs/jbd2/commit.c, 370): jbd2_journal_commit_transaction: JBD2: want 42104, j_commit_sequence=42103
[* 290.339382] JBD2: starting commit of transaction 42104
[ 290.339410] (fs/jbd2/revoke.c, 566): jbd2_journal_write_revoke_records: Wrote 0 revoke records
[ 290.376555] (fs/jbd2/commit.c, 1088): jbd2_journal_commit_transaction: JBD2: commit 42104 complete, head 42079
i.e. the debug output from log_wait_commit and journal_commit_transaction
have become interleaved. The output should have been:
(fs/jbd2/journal.c, 648): jbd2_log_wait_commit: JBD2: want 42104, j_commit_sequence=42103
(fs/jbd2/commit.c, 370): jbd2_journal_commit_transaction: JBD2: starting commit of transaction 42104
It is expected that this is not easy to replicate -- I was only able
to cause it on preempt-rt kernels, and even then only under heavy
I/O load.
--------------
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
fs/jbd/journal.c | 18 ++++++++++++++++++
include/linux/jbd.h | 15 ++++++---------
2 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
index 166263d..f45f0a3 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -97,6 +97,24 @@ static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
static void __journal_abort_soft (journal_t *journal, int errno);
static const char *journal_dev_name(journal_t *journal, char *buffer);
+#ifdef CONFIG_JBD_DEBUG
+void __jbd_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ if (level > jbd_journal_enable_debug)
+ return;
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf);
+ va_end(args);
+}
+EXPORT_SYMBOL(__jbd_debug);
+#endif
+
/*
* Helper function used to manage commit timeouts
*/
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index e45b430..d6d3ae0 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -56,16 +56,13 @@
#define JBD_EXPENSIVE_CHECKING
extern ushort journal_enable_debug;
-#define jbd_debug(n, f, a...) \
- do { \
- if ((n) <= journal_enable_debug) { \
- printk (KERN_DEBUG "(%s, %d): %s: ", \
- __FILE__, __LINE__, __func__); \
- printk (f, ## a); \
- } \
- } while (0)
+void __jbd_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...);
+
+#define jbd_debug(n, fmt, a...) \
+ __jbd_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
#else
-#define jbd_debug(f, a...) /**/
+#define jbd_debug(n, fmt, a...) /**/
#endif
static inline void *jbd_alloc(size_t size, gfp_t flags)
--
1.8.1.2
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