From: NeilBrown <neilb@suse.de>
Date: Sat, 14 Aug 2010 05:01:34 +0000 (+1000)
Subject: Use a new flag to identify blocks being processed by the cleaner.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=b8f0eb4ee25d9aa71d1e6d64118648bcb79127f0;p=LaFS.git

Use a new flag to identify blocks being processed by the cleaner.

This will help future patch which will unify cleaning and orphans
list_heads, and make is clear when a refcount is being help.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/clean.c b/clean.c
index 806f9cf..aff7c95 100644
--- a/clean.c
+++ b/clean.c
@@ -291,11 +291,13 @@ static int try_clean(struct fs *fs, struct toclean *tc)
 			if (b == NULL)
 				break;
 
-			if (list_empty(&b->cleaning)) {
-				list_add_tail(&b->cleaning, &tc->cleaning);
+			if (!test_and_set_bit(B_Cleaning, &b->b.flags)) {
 				getdref(b, MKREF(cleaning));
 				igrab(ino);
 			}
+			if (list_empty(&b->cleaning))
+				list_add_tail(&b->cleaning, &tc->cleaning);
+
 			/* FIXME do I need a memory barrier. to ensure truncate
 			 * sees the not-list_empty, and we see i_size? */
 
@@ -304,8 +306,10 @@ static int try_clean(struct fs *fs, struct toclean *tc)
 			     ((loff_t)bnum << ino->i_blkbits)
 			     >= i_size_read(ino))) {
 				list_del_init(&b->cleaning);
-				putdref(b, MKREF(cleaning));
-				iput(ino);
+				if (test_and_clear_bit(B_Cleaning, &b->b.flags)) {
+					putdref(b, MKREF(cleaning));
+					iput(ino);
+				}
 			}
 			putdref(b, MKREF(cleaning));
 		}
@@ -361,10 +365,12 @@ static int try_clean(struct fs *fs, struct toclean *tc)
 		 */
 	done_cleaning:
 		list_del_init(&b->cleaning);
-		ino = b->b.inode;
-		putdref(b, MKREF(cleaning));
+		if (test_and_clear_bit(B_Cleaning, &b->b.flags)) {
+			ino = b->b.inode;
+			putdref(b, MKREF(cleaning));
+			iput(ino);
+		}
 		putref(cb, MKREF(clean2));
-		iput(ino);
 		if (rv)
 			goto out;
 	}
@@ -380,8 +386,9 @@ void lafs_unclean(struct datablock *db)
 	if (!list_empty_careful(&db->cleaning)) {
 		struct fs *fs = fs_from_inode(db->b.inode);
 		mutex_lock(&fs->cleaner.lock);
-		if (!list_empty(&db->cleaning)) {
+		if (!list_empty(&db->cleaning))
 			list_del_init(&db->cleaning);
+		if (test_and_clear_bit(B_Cleaning, &db->b.flags)) {
 			putdref(db, MKREF(cleaning));
 			iput(db->b.inode);
 			if (test_and_clear_bit(B_Async, &db->b.flags)) {
diff --git a/state.h b/state.h
index 0c10615..01b03d3 100644
--- a/state.h
+++ b/state.h
@@ -433,7 +433,7 @@ struct indexblock {
 #define dblk(__bl) container_of(__bl, struct datablock, b)
 
 enum {
-	/* NOTE: 31 flags in used.  Need to overlap 'data' with 'index' if
+	/* NOTE: 32 flags in used.  Need to overlap 'data' with 'index' if
 	 * we need much more
 	 */
 	/* First flags that are meaningful for both Data and Index blocks
@@ -472,7 +472,7 @@ enum {
 	B_PhysValid,	/* ->physaddr is correct */
 
 	/* Flags that are only relevant for Data Block
-	 * currently 6 */
+	 * currently 7 */
 
 	B_PinPending,	 /* set on data blocks while checkpoint_locked if we might
 			   * want to mark them dirty
@@ -487,8 +487,11 @@ enum {
 	B_HaveWriteback,/* We own the page writeback flag and when all blocks
 			 * are unlocked we should clear it. */
 	B_Claimed,	/* Used for exclusive allocation of inodes */
+	B_Cleaning,	/* Used by cleaner to track which blocks it has a
+			 * reference on already. */
+
 	/* Flags that are only relevant for Index Blocks
-	 * currently 2 */
+	 * currently 3 */
 	B_OnFree,	/* index block on the free list */
 	B_PrimaryRef,	/* This indexblock has not been incorporated into the
 			 * parent, and so can only be found by being a sibling