Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e99a03c6 authored by Paul Gortmaker's avatar Paul Gortmaker Committed by Jan Kara
Browse files

jbd: use a single printk for jbd_debug() 



Backport of jbd2 commit 169f1a2a
("jbd2: use a single printk for jbd_debug()")

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: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent a91de852

fs/jbd/journal.c

+18 −0
Original line number Diff line number Diff line
@@ -90,6 +90,24 @@ 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 > 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

 */

include/linux/jbd.h

+6 −9
Original line number Diff line number Diff line
@@ -57,16 +57,13 @@ 
#define JBD_EXPENSIVE_CHECKING

extern u8 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)