1 files changed, 16 insertions, 0 deletions

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index d23d6d7a45a6..04e3c42a085f 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2801,11 +2801,27 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
                 goto free_and_return;
         }
 
+        /*
+         * We need to unlock here to avoid creating the following
+         * dependency:
+         * reiserfs_lock -> sysfs_mutex
+         * Because the reiserfs mmap path creates the following dependency:
+         * mm->mmap -> reiserfs_lock, hence we have
+         * mm->mmap -> reiserfs_lock ->sysfs_mutex
+         * This would ends up in a circular dependency with sysfs readdir path
+         * which does sysfs_mutex -> mm->mmap_sem
+         * This is fine because the reiserfs lock is useless in mount path,
+         * at least until we call journal_begin. We keep it for paranoid
+         * reasons.
+         */
+        reiserfs_write_unlock(sb);
         if (journal_init_dev(sb, journal, j_dev_name) != 0) {
+                reiserfs_write_lock(sb);
                 reiserfs_warning(sb, "sh-462",
                                  "unable to initialize jornal device");
                 goto free_and_return;
         }
+        reiserfs_write_lock(sb);
 
         rs = SB_DISK_SUPER_BLOCK(sb);