Author: mckusick
Date: Sun Dec  1 07:34:21 2013
New Revision: 258789
URL: http://svnweb.freebsd.org/changeset/base/258789

Log:
  We needlessly panic when trying to flush MKDIR_PARENT dependencies.
  We had previously tried to flush all MKDIR_PARENT dependencies (and
  all the NEWBLOCK pagedeps) by calling ffs_update(). However this will
  only resolve these dependencies in direct blocks. So very large
  directories with MKDIR_PARENT dependencies in indirect blocks had
  not yet gotten flushed. As the directory is in the midst of doing a
  complete sync, we simply defer the checking of the MKDIR_PARENT
  dependencies until the indirect blocks have been sync'ed.
  
  Reported by: Shawn Wallbridge of imaginaryforces.com
  Tested by:   John-Mark Gurney <[email protected]>
  PR:          183424
  MFC after:   2 weeks

Modified:
  head/sys/ufs/ffs/ffs_softdep.c

Modified: head/sys/ufs/ffs/ffs_softdep.c
==============================================================================
--- head/sys/ufs/ffs/ffs_softdep.c      Sun Dec  1 03:53:21 2013        
(r258788)
+++ head/sys/ufs/ffs/ffs_softdep.c      Sun Dec  1 07:34:21 2013        
(r258789)
@@ -12709,7 +12709,9 @@ flush_pagedep_deps(pvp, mp, diraddhdp)
        int error = 0;
        struct buf *bp;
        ino_t inum;
+       struct diraddhd unfinished;
 
+       LIST_INIT(&unfinished);
        ump = VFSTOUFS(mp);
        LOCK_OWNED(ump);
 restart:
@@ -12728,8 +12730,20 @@ restart:
                         */
                        if (dap != LIST_FIRST(diraddhdp))
                                continue;
-                       if (dap->da_state & MKDIR_PARENT)
-                               panic("flush_pagedep_deps: MKDIR_PARENT");
+                       /*
+                        * All MKDIR_PARENT dependencies and all the
+                        * NEWBLOCK pagedeps that are contained in direct
+                        * blocks were resolved by doing above ffs_update.
+                        * Pagedeps contained in indirect blocks may
+                        * require a complete sync'ing of the directory.
+                        * We are in the midst of doing a complete sync,
+                        * so if they are not resolved in this pass we
+                        * defer them for now as they will be sync'ed by
+                        * our caller shortly.
+                        */
+                       LIST_REMOVE(dap, da_pdlist);
+                       LIST_INSERT_HEAD(&unfinished, dap, da_pdlist);
+                       continue;
                }
                /*
                 * A newly allocated directory must have its "." and
@@ -12838,6 +12852,10 @@ retry:
        }
        if (error)
                ACQUIRE_LOCK(ump);
+       while ((dap = LIST_FIRST(&unfinished)) != NULL) {
+               LIST_REMOVE(dap, da_pdlist);
+               LIST_INSERT_HEAD(diraddhdp, dap, da_pdlist);
+       }
        return (error);
 }
 
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