svn commit: r329078 - in head/sys: kern sys

[Kirk McKusick]

Author: mckusick
Date: Fri Feb  9 19:50:47 2018
New Revision: 329078
URL: https://svnweb.freebsd.org/changeset/base/329078

Log:
  Merge biodone_finish() back into biodone(). The primary purpose is
  to make the order of operations clearer to avoid the race condition
  that was fixed in r328914. In particular, this commit corrects a
  similar race that existed in the soft updates callback.
  
  Doing some sleuthing through the SVN repository, it appears that
  bufdone_finish() was added to support XFS:
  
  ------------------------------------------------------------------------
  r153192 | rodrigc | 2005-12-06 19:39:08 -0800 (Tue, 06 Dec 2005) | 13 lines
  
  Changes imported from XFS for FreeBSD project:
  - add fields to struct buf (needed by XFS)
      - 3 private fields: b_fsprivate1, b_fsprivate2, b_fsprivate3
      - b_pin_count, count of pinned buffer
  
  - add new B_MANAGED flag
  - add breada() function to initiate asynchronous I/O on read-ahead blocks.
  - add bufdone_finish(), bpin(), bunpin_wait() functions
  
  Patches provided by:    kan
  Reviewed by:            phk
  Silence on:             arch@
  
  ------------------------------------------------------------------------
  
  It does not appear to ever have been used for anything else.  XFS was
  disconnected in r241607:
  
  ------------------------------------------------------------------------
  r241607 | attilio | 2012-10-16 03:04:00 -0700 (Tue, 16 Oct 2012) | 5 lines
  
  Disconnect non-MPSAFE XFS from the build in preparation for dropping
  GIANT from VFS.
  
  This is not targeted for MFC.
  
  ------------------------------------------------------------------------
  
  and removed entirely in r247631:
  
  ------------------------------------------------------------------------
  r247631 | attilio | 2013-03-02 07:33:54 -0800 (Sat, 02 Mar 2013) | 5 lines
  
  Garbage collect XFS bits which are now already completely disconnected
  from the tree since few months.
  
  This is not targeted for MFC.
  
  ------------------------------------------------------------------------
  
  Since XFS support is gone, there is no reason to retain biodone_finish().
  
  Suggested by: Warner Losh (imp)
  Discussed with: cem, kib
  Tested by: Peter Holm (pho)

Modified:
  head/sys/kern/vfs_bio.c
  head/sys/sys/buf.h

Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c	Fri Feb  9 19:46:51 2018	(r329077)
+++ head/sys/kern/vfs_bio.c	Fri Feb  9 19:50:47 2018	(r329078)
@@ -4086,21 +4086,6 @@ bufdone(struct buf *bp)
 			bufobj_wdrop(dropobj);
 		return;
 	}
-
-	bufdone_finish(bp);
-
-	if (dropobj)
-		bufobj_wdrop(dropobj);
-}
-
-void
-bufdone_finish(struct buf *bp)
-{
-	BUF_ASSERT_HELD(bp);
-
-	if (!LIST_EMPTY(&bp->b_dep))
-		buf_complete(bp);
-
 	if (bp->b_flags & B_VMIO) {
 		/*
 		 * Set B_CACHE if the op was a normal read and no error
@@ -4113,14 +4098,14 @@ bufdone_finish(struct buf *bp)
 			bp->b_flags |= B_CACHE;
 		vfs_vmio_iodone(bp);
 	}
+	if (!LIST_EMPTY(&bp->b_dep))
+		buf_complete(bp);
 	if ((bp->b_flags & B_CKHASH) != 0) {
 		KASSERT(bp->b_iocmd == BIO_READ,
-		    ("bufdone_finish: b_iocmd %d not BIO_READ", bp->b_iocmd));
-		KASSERT(buf_mapped(bp),
-		    ("bufdone_finish: bp %p not mapped", bp));
+		    ("bufdone: b_iocmd %d not BIO_READ", bp->b_iocmd));
+		KASSERT(buf_mapped(bp), ("bufdone: bp %p not mapped", bp));
 		(*bp->b_ckhashcalc)(bp);
 	}
-
 	/*
 	 * For asynchronous completions, release the buffer now. The brelse
 	 * will do a wakeup there if necessary - so no need to do a wakeup
@@ -4134,6 +4119,8 @@ bufdone_finish(struct buf *bp)
 			bqrelse(bp);
 	} else
 		bdone(bp);
+	if (dropobj)
+		bufobj_wdrop(dropobj);
 }
 
 /*

Modified: head/sys/sys/buf.h
==============================================================================
--- head/sys/sys/buf.h	Fri Feb  9 19:46:51 2018	(r329077)
+++ head/sys/sys/buf.h	Fri Feb  9 19:50:47 2018	(r329078)
@@ -542,7 +542,6 @@ struct buf *geteblk(int, int);
 int	bufwait(struct buf *);
 int	bufwrite(struct buf *);
 void	bufdone(struct buf *);
-void	bufdone_finish(struct buf *);
 void	bd_speedup(void);
 
 int	cluster_read(struct vnode *, u_quad_t, daddr_t, long,