diff options
| author | Paul Gortmaker <paul.gortmaker@windriver.com> | 2013-06-12 23:04:04 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-06-12 23:04:04 -0400 |
| commit | 169f1a2a87aae44034da4b9f81be1683d33de6d0 (patch) | |
| tree | d6283b5c33699eaf22ea52c3298d38be0152059d | |
| parent | c9b3a8ccb77e063a28a9567eb72e0c1222c4ade4 (diff) | |
| download | lwn-169f1a2a87aae44034da4b9f81be1683d33de6d0.tar.gz lwn-169f1a2a87aae44034da4b9f81be1683d33de6d0.zip | |
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.c | 18 | ||||
| -rw-r--r-- | include/linux/jbd2.h | 14 |
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); |