linux-ext4 - [PATCH 1/6] libext2fs: improve jbd

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Message-Id: <20210616045334.1655288-2-ebiggers@kernel.org>
Date:   Tue, 15 Jun 2021 21:53:29 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-ext4@...r.kernel.org
Subject: [PATCH 1/6] libext2fs: improve jbd_debug() implementation

From: Eric Biggers <ebiggers@...gle.com>

Make jbd_debug() do format string checking (but still get compiled away
to nothing) when --enable-jbd-debug isn't specified, similar to
commit d556435156b7 ("jbd2: avoid -Wempty-body warnings") on the kernel
side.  This should prevent --enable-jbd-debug from getting broken due to
bad jbd_debug() statements.  It also eliminates a -Wunused-variable
warning where a variable was only used in a jbd_debug() statement.

Also remove an alternative definition of jbd_debug() that was
conditional on CONFIG_JBD_DEBUG && !CONFIG_JBD_DEBUG, so was dead code.

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 debugfs/journal.c       |  4 ----
 e2fsck/journal.c        |  4 ----
 lib/ext2fs/kernel-jbd.h | 26 +++++---------------------
 3 files changed, 5 insertions(+), 29 deletions(-)

diff --git a/debugfs/journal.c b/debugfs/journal.c
index e8872f05..686d0eb0 100644
--- a/debugfs/journal.c
+++ b/debugfs/journal.c
@@ -26,9 +26,7 @@
 #include "uuid/uuid.h"
 #include "journal.h"
 
-#ifdef CONFIG_JBD_DEBUG		/* Enabled by configure --enable-jfs-debug */
 static int bh_count = 0;
-#endif
 
 #if EXT2_FLAT_INCLUDES
 #include "blkid.h"
@@ -135,10 +133,8 @@ struct buffer_head *getblk(kdev_t kdev, unsigned long long blocknr,
 	if (retval)
 		return NULL;
 
-#ifdef CONFIG_JBD_DEBUG
 	if (journal_enable_debug >= 3)
 		bh_count++;
-#endif
 	jfs_debug(4, "getblk for block %llu (%d bytes)(total %d)\n",
 		  blocknr, blocksize, bh_count);
 
diff --git a/e2fsck/journal.c b/e2fsck/journal.c
index a425bbd1..a0a4d968 100644
--- a/e2fsck/journal.c
+++ b/e2fsck/journal.c
@@ -27,9 +27,7 @@
 #include "problem.h"
 #include "uuid/uuid.h"
 
-#ifdef CONFIG_JBD_DEBUG		/* Enabled by configure --enable-jfs-debug */
 static int bh_count = 0;
-#endif
 
 /*
  * Define USE_INODE_IO to use the inode_io.c / fileio.c codepaths.
@@ -129,10 +127,8 @@ struct buffer_head *getblk(kdev_t kdev, unsigned long long blocknr,
 	if (!bh)
 		return NULL;
 
-#ifdef CONFIG_JBD_DEBUG
 	if (journal_enable_debug >= 3)
 		bh_count++;
-#endif
 	jfs_debug(4, "getblk for block %llu (%d bytes)(total %d)\n",
 		  blocknr, blocksize, bh_count);
 
diff --git a/lib/ext2fs/kernel-jbd.h b/lib/ext2fs/kernel-jbd.h
index 2978ccb6..c94de237 100644
--- a/lib/ext2fs/kernel-jbd.h
+++ b/lib/ext2fs/kernel-jbd.h
@@ -26,7 +26,6 @@
 
 #define journal_oom_retry 0
 
-#ifdef __STDC__
 #ifdef CONFIG_JBD_DEBUG
 /*
  * Define JBD_EXPENSIVE_CHECKING to enable more expensive internal
@@ -35,7 +34,11 @@
  */
 #define JBD_EXPENSIVE_CHECKING
 extern int journal_enable_debug;
+#else
+#define journal_enable_debug (-1)
+#endif /* !CONFIG_JBD_DEBUG */
 
+#ifdef __STDC__
 #define jbd_debug(n, f, a...)						\
 	do {								\
 		if ((n) <= journal_enable_debug) {			\
@@ -45,27 +48,8 @@ extern int journal_enable_debug;
 		}							\
 	} while (0)
 #else
-#ifdef __GNUC__
-#if defined(__KERNEL__) || !defined(CONFIG_JBD_DEBUG)
-#define jbd_debug(f, a...)	/**/
-#else
-extern int journal_enable_debug;
-#define jbd_debug(n, f, a...)						\
-	do {								\
-		if ((n) <= journal_enable_debug) {			\
-			printf("(%s, %d): %s: ",			\
-				__FILE__, __LINE__, __func__);		\
-			printf(f, ## a);				\
-		}							\
-	} while (0)
-#endif /*__KERNEL__ */
-#else
-#define jbd_debug(f, ...)	/**/
-#endif
-#endif
-#else
 #define jbd_debug(x)		/* AIX doesn't do STDC */
-#endif
+#endif /* !__STDC__ */
 
 extern void * __jbd_kmalloc (char *where, size_t size, int flags, int retry);
 #define jbd_kmalloc(size, flags) \
-- 
2.32.0.272.g935e593368-goog