[XFS] avoid memory allocations in xfs_fs_vcmn_err

xfs_fs_vcmn_err can be called under a spinlock, but does a sleeping memory
allocation to create buffer for it's internal sprintf.  Fortunately it's
the only caller of icmn_err, so we can merge the two and have one single
static buffer and spinlock protecting it.  While we're at it make sure
we proper __attribute__ format annotations so that the compiler can detect
mismatched format strings.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 32 insertions, 5 deletions

diff --git a/fs/xfs/support/debug.c b/fs/xfs/support/debug.c
index 636104254cfd..ae5482965424 100644
--- a/fs/xfs/support/debug.c
+++ b/fs/xfs/support/debug.c
@@ -18,6 +18,13 @@
 #include <xfs.h>
 #include "debug.h"
 
+/* xfs_mount.h drags a lot of crap in, sorry.. */
+#include "xfs_sb.h"
+#include "xfs_inum.h"
+#include "xfs_ag.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+
 static char             message[1024];  /* keep it off the stack */
 static DEFINE_SPINLOCK(xfs_err_lock);
 
@@ -55,22 +62,42 @@ cmn_err(register int level, char *fmt, ...)
 }
 
 void
-icmn_err(register int level, char *fmt, va_list ap)
+xfs_fs_vcmn_err(
+        int                     level,
+        struct xfs_mount        *mp,
+        char                    *fmt,
+        va_list                 ap)
 {
-        ulong   flags;
-        int     len;
+        unsigned long           flags;
+        int                     len = 0;
 
         level &= XFS_ERR_MASK;
-        if(level > XFS_MAX_ERR_LEVEL)
+        if (level > XFS_MAX_ERR_LEVEL)
                 level = XFS_MAX_ERR_LEVEL;
+
         spin_lock_irqsave(&xfs_err_lock,flags);
-        len = vsnprintf(message, sizeof(message), fmt, ap);
+
+        if (mp) {
+                len = sprintf(message, "Filesystem \"%s\": ", mp->m_fsname);
+
+                /*
+                 * Skip the printk if we can't print anything useful
+                 * due to an over-long device name.
+                 */
+                if (len >= sizeof(message))
+                        goto out;
+        }
+
+        len = vsnprintf(message + len, sizeof(message) - len, fmt, ap);
         if (len >= sizeof(message))
                 len = sizeof(message) - 1;
         if (message[len-1] == '\n')
                 message[len-1] = 0;
+
         printk("%s%s\n", err_level[level], message);
+ out:
         spin_unlock_irqrestore(&xfs_err_lock,flags);
+
         BUG_ON(level == CE_PANIC);
 }