1 files changed, 84 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2963376e77f4..52e903b0a293 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -54,6 +54,90 @@
 
 static const struct super_operations btrfs_super_ops;
 
+static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
+                                      char nbuf[16])
+{
+        char *errstr = NULL;
+
+        switch (errno) {
+        case -EIO:
+                errstr = "IO failure";
+                break;
+        case -ENOMEM:
+                errstr = "Out of memory";
+                break;
+        case -EROFS:
+                errstr = "Readonly filesystem";
+                break;
+        default:
+                if (nbuf) {
+                        if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
+                                errstr = nbuf;
+                }
+                break;
+        }
+
+        return errstr;
+}
+
+static void __save_error_info(struct btrfs_fs_info *fs_info)
+{
+        /*
+         * today we only save the error info into ram.  Long term we'll
+         * also send it down to the disk
+         */
+        fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
+}
+
+/* NOTE:
+ *      We move write_super stuff at umount in order to avoid deadlock
+ *      for umount hold all lock.
+ */
+static void save_error_info(struct btrfs_fs_info *fs_info)
+{
+        __save_error_info(fs_info);
+}
+
+/* btrfs handle error by forcing the filesystem readonly */
+static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
+{
+        struct super_block *sb = fs_info->sb;
+
+        if (sb->s_flags & MS_RDONLY)
+                return;
+
+        if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                sb->s_flags |= MS_RDONLY;
+                printk(KERN_INFO "btrfs is forced readonly\n");
+        }
+}
+
+/*
+ * __btrfs_std_error decodes expected errors from the caller and
+ * invokes the approciate error response.
+ */
+void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
+                     unsigned int line, int errno)
+{
+        struct super_block *sb = fs_info->sb;
+        char nbuf[16];
+        const char *errstr;
+
+        /*
+         * 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;
+
+        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);
+
+        btrfs_handle_error(fs_info);
+}
+
 static void btrfs_put_super(struct super_block *sb)
 {
         struct btrfs_root *root = btrfs_sb(sb);