[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>

4 files changed, 40 insertions, 26 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);
 }
 
diff --git a/fs/xfs/support/debug.h b/fs/xfs/support/debug.h
index 75845f950814..6f4fd37c67af 100644
--- a/fs/xfs/support/debug.h
+++ b/fs/xfs/support/debug.h
@@ -27,8 +27,6 @@
 #define CE_ALERT        1               /* alert        */
 #define CE_PANIC        0               /* panic        */
 
-extern void icmn_err(int, char *, va_list)
-        __attribute__ ((format (printf, 2, 0)));
 extern void cmn_err(int, char *, ...)
         __attribute__ ((format (printf, 2, 3)));
 extern void assfail(char *expr, char *f, int l);
diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index f227ecd1a294..92d5cd5bf4f2 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -153,21 +153,6 @@ xfs_errortag_clearall(xfs_mount_t *mp, int loud)
 }
 #endif /* DEBUG */
 
-static void
-xfs_fs_vcmn_err(int level, xfs_mount_t *mp, char *fmt, va_list ap)
-{
-        if (mp != NULL) {
-                char    *newfmt;
-                int     len = 16 + mp->m_fsname_len + strlen(fmt);
-
-                newfmt = kmem_alloc(len, KM_SLEEP);
-                sprintf(newfmt, "Filesystem \"%s\": %s", mp->m_fsname, fmt);
-                icmn_err(level, newfmt, ap);
-                kmem_free(newfmt);
-        } else {
-                icmn_err(level, fmt, ap);
-        }
-}
 
 void
 xfs_fs_cmn_err(int level, xfs_mount_t *mp, char *fmt, ...)
diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h
index 11543f10b0c6..0c93051c4651 100644
--- a/fs/xfs/xfs_error.h
+++ b/fs/xfs/xfs_error.h
@@ -159,11 +159,15 @@ extern int xfs_errortag_clearall(xfs_mount_t *mp, int loud);
 #define         XFS_PTAG_FSBLOCK_ZERO           0x00000080
 
 struct xfs_mount;
-/* PRINTFLIKE4 */
+
+extern void xfs_fs_vcmn_err(int level, struct xfs_mount *mp,
+                char *fmt, va_list ap)
+        __attribute__ ((format (printf, 3, 0)));
 extern void xfs_cmn_err(int panic_tag, int level, struct xfs_mount *mp,
-                        char *fmt, ...);
-/* PRINTFLIKE3 */
-extern void xfs_fs_cmn_err(int level, struct xfs_mount *mp, char *fmt, ...);
+                        char *fmt, ...)
+        __attribute__ ((format (printf, 4, 5)));
+extern void xfs_fs_cmn_err(int level, struct xfs_mount *mp, char *fmt, ...)
+        __attribute__ ((format (printf, 3, 4)));
 
 extern void xfs_hex_dump(void *p, int length);