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authorPaul Gortmaker <paul.gortmaker@windriver.com>2013-06-12 23:04:04 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-06-12 23:04:04 -0400
commit169f1a2a87aae44034da4b9f81be1683d33de6d0 (patch)
treed6283b5c33699eaf22ea52c3298d38be0152059d
parentc9b3a8ccb77e063a28a9567eb72e0c1222c4ade4 (diff)
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. Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Suggested-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/jbd2/journal.c18
-rw-r--r--include/linux/jbd2.h14
2 files changed, 23 insertions, 9 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0e6c13bdcc14..915dd575cd46 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -103,6 +103,24 @@ EXPORT_SYMBOL(jbd2_inode_cache);
static void __journal_abort_soft (journal_t *journal, int errno);
static int jbd2_journal_create_slab(size_t slab_size);
+#ifdef CONFIG_JBD2_DEBUG
+void __jbd2_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ if (level > jbd2_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(__jbd2_debug);
+#endif
+
/* Checksumming functions */
int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
{
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 25d9c9ea7a14..0302f3f14063 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -56,17 +56,13 @@
*/
#define JBD2_EXPENSIVE_CHECKING
extern ushort jbd2_journal_enable_debug;
+void __jbd2_debug(int level, const char *file, const char *func,
+ unsigned int line, const char *fmt, ...);
-#define jbd_debug(n, f, a...) \
- do { \
- if ((n) <= jbd2_journal_enable_debug) { \
- printk (KERN_DEBUG "(%s, %d): %s: ", \
- __FILE__, __LINE__, __func__); \
- printk (f, ## a); \
- } \
- } while (0)
+#define jbd_debug(n, fmt, a...) \
+ __jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
#else
-#define jbd_debug(f, a...) /**/
+#define jbd_debug(n, fmt, a...) /**/
#endif
extern void *jbd2_alloc(size_t size, gfp_t flags);