From e99a03c6f50a699d63b5751e3e88f84e43b037a7 Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Thu, 1 Aug 2013 15:01:08 -0400 Subject: jbd: use a single printk for jbd_debug() Backport of jbd2 commit 169f1a2a87aae44034da4b9f81be1683d33de6d0 ("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: Paul Gortmaker Signed-off-by: Jan Kara --- fs/jbd/journal.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/jbd') diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c index 6510d6355729..2d04f9afafd7 100644 --- a/fs/jbd/journal.c +++ b/fs/jbd/journal.c @@ -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 */ -- cgit v1.2.3-59-g8ed1b