From: Alan Cox <alan@linux.intel.com>
Date: Wed, 18 Apr 2018 22:44:45 +0000 (+0100)
Subject: kernel: hopefully fix the busy block panic
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=a0a8573af04efa37e0287e32955a76896c60a892;p=FUZIX.git

kernel: hopefully fix the busy block panic

Do make backups before you test this!
---

diff --git a/Kernel/devio.c b/Kernel/devio.c
index 3181d0f4..8052a4d3 100644
--- a/Kernel/devio.c
+++ b/Kernel/devio.c
@@ -103,7 +103,6 @@ bufptr bread(uint16_t dev, blkno_t blk, bool rewrite)
 			}
 		}
 	}
-	bp->bf_time = ++bufclock;	/* Time stamp it */
 	return bp;
 }
 
@@ -142,6 +141,11 @@ int bfree(regptr bufptr bp, uint8_t dirty)
 		}
 		bp->bf_dirty = false;
 	}
+	/* Time stamp the buffer on free up. It doesn't matter if we stamp it
+	   on read or free as while locked it can't go away. However if we
+	   stamp it on free we can in future make smarter decisions such as
+	   recycling full dirty buffers faster than partial ones */
+	bp->bf_time = ++bufclock;
 	bunlock(bp);
 	return ret;
 }
diff --git a/Kernel/filesys.c b/Kernel/filesys.c
index 247f6141..3c9e76e7 100644
--- a/Kernel/filesys.c
+++ b/Kernel/filesys.c
@@ -650,6 +650,11 @@ blkno_t blk_alloc(uint16_t devno)
         goto corrupt;
     --dev->s_tfree;
 
+   /*
+    * FIXME: When we implement the rest of the bigger block size fs support
+    * this routine is responsible for zeroing the entire extent not just the
+    * 512 byte block
+    */
     /* Zero out the new block */
     buf = bread(devno, newno, 2);
     if (buf == NULL)
diff --git a/Kernel/inode.c b/Kernel/inode.c
index d4123439..9e3dacf1 100644
--- a/Kernel/inode.c
+++ b/Kernel/inode.c
@@ -113,22 +113,14 @@ void readi(regptr inoptr ino, uint8_t flag)
 			} else
 #endif
 			{
-				/* FIXME: for big file system support we need
-				   to zero the rest of the logical extent here
-				   and then allocate and write the one we want */
 				/* we transfer through the buffer pool */
 				if (pblk == NULLBLK)
 					bp = zerobuf();
-				else if (bp == NULL) {
+				else if (bp == NULL)
 					bp = bread(dev, pblk, 0);
-					if (bp == NULL)
-						break;
-				} else {
-					/* FIXME: this has to get sorted ASAP */
-					bp->bf_time = ++bufclock;
-				}
+				if (bp == NULL)
+					break;
 				uputblk(bp, uoff(), amount);
-
 				brelse(bp);
 			}
 			/* Bletch */