btrfs: add varargs to btrfs_error

 btrfs currently handles most errors with BUG_ON. This patch is a work-in-
 progress but aims to handle most errors other than internal logic
 errors and ENOMEM more gracefully.

 This iteration prevents most crashes but can run into lockups with
 the page lock on occasion when the timing "works out."

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f6bca05a4b4c37acae6d02f0014a4c95b66f47b2..8829f80998513fb7b7cfa2c4fd9e5ff68c15b0f7 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2964,13 +2964,21 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 /* super.c */
 int btrfs_parse_options(struct btrfs_root *root, char *options);
 int btrfs_sync_fs(struct super_block *sb, int wait);
+void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...);
 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
-                    unsigned int line, int errno);
+                    unsigned int line, int errno, const char *fmt, ...);
 
 #define btrfs_std_error(fs_info, errno)                                \
 do {                                                           \
        if ((errno))                                            \
-               __btrfs_std_error((fs_info), __func__, __LINE__, (errno));\
+               __btrfs_std_error((fs_info), __func__,          \
+                                  __LINE__, (errno), NULL);    \
+} while (0)
+
+#define btrfs_error(fs_info, errno, fmt, args...)              \
+do {                                                           \
+       __btrfs_std_error((fs_info), __func__, __LINE__,        \
+                         (errno), fmt, ##args);                \
 } while (0)
 
 void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ae7963b2d5277c0a9e2eba1c7e4e12edf772572c..7fe69eef7607039ad8e486c628377300f5cb5c26 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -127,25 +127,74 @@ static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
  * invokes the approciate error response.
  */
 void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
-                    unsigned int line, int errno)
+                      unsigned int line, int errno, const char *fmt, ...)
 {
        struct super_block *sb = fs_info->sb;
        char nbuf[16];
        const char *errstr;
+       va_list args;
+       va_start(args, fmt);
 
        /*
         * Special case: if the error is EROFS, and we're already
         * under MS_RDONLY, then it is safe here.
         */
        if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
-               return;
+               return;
 
-       errstr = btrfs_decode_error(fs_info, errno, nbuf);
-       printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
-               sb->s_id, function, line, errstr);
-       save_error_info(fs_info);
+       errstr = btrfs_decode_error(fs_info, errno, nbuf);
+       if (fmt) {
+               struct va_format vaf = {
+                       .fmt = fmt,
+                       .va = &args,
+               };
+
+               printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
+                       sb->s_id, function, line, errstr, &vaf);
+       } else {
+               printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
+                       sb->s_id, function, line, errstr);
+       }
+
+       /* Don't go through full error handling during mount */
+       if (sb->s_flags & MS_BORN) {
+               save_error_info(fs_info);
+               btrfs_handle_error(fs_info);
+       }
+       va_end(args);
+}
 
-       btrfs_handle_error(fs_info);
+const char *logtypes[] = {
+       "emergency",
+       "alert",
+       "critical",
+       "error",
+       "warning",
+       "notice",
+       "info",
+       "debug",
+};
+
+void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
+{
+       struct super_block *sb = fs_info->sb;
+       char lvl[4];
+       struct va_format vaf;
+       va_list args;
+       const char *type = logtypes[4];
+
+       va_start(args, fmt);
+
+       if (fmt[0] == '<' && isdigit(fmt[1]) && fmt[2] == '>') {
+               strncpy(lvl, fmt, 3);
+               fmt += 3;
+               type = logtypes[fmt[1] - '0'];
+       } else
+               *lvl = '\0';
+
+       vaf.fmt = fmt;
+       vaf.va = &args;
+       printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
 }
 
 /*