reiserfs: locking, handle nested locks properly

The reiserfs write lock replaced the BKL and uses similar semantics.

Frederic's locking code makes a distinction between when the lock is nested
and when it's being acquired/released, but I don't think that's the right
distinction to make.

The right distinction is between the lock being released at end-of-use and
the lock being released for a schedule. The unlock should return the depth
and the lock should restore it, rather than the other way around as it is now.

This patch implements that and adds a number of places where the lock
should be dropped.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/fs/reiserfs/fix_node.c b/fs/reiserfs/fix_node.c
index 430e0658704c..dc4d41530316 100644
--- a/fs/reiserfs/fix_node.c
+++ b/fs/reiserfs/fix_node.c
@@ -1022,9 +1022,9 @@ static int get_far_parent(struct tree_balance *tb,
 	if (buffer_locked(*pcom_father)) {
 
 		/* Release the write lock while the buffer is busy */
-		reiserfs_write_unlock(tb->tb_sb);
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
 		__wait_on_buffer(*pcom_father);
-		reiserfs_write_lock(tb->tb_sb);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
 		if (FILESYSTEM_CHANGED_TB(tb)) {
 			brelse(*pcom_father);
 			return REPEAT_SEARCH;
@@ -1929,9 +1929,9 @@ static int get_direct_parent(struct tree_balance *tb, int h)
 		return REPEAT_SEARCH;
 
 	if (buffer_locked(bh)) {
-		reiserfs_write_unlock(tb->tb_sb);
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
 		__wait_on_buffer(bh);
-		reiserfs_write_lock(tb->tb_sb);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
 		if (FILESYSTEM_CHANGED_TB(tb))
 			return REPEAT_SEARCH;
 	}
@@ -1952,6 +1952,7 @@ static int get_neighbors(struct tree_balance *tb, int h)
 	unsigned long son_number;
 	struct super_block *sb = tb->tb_sb;
 	struct buffer_head *bh;
+	int depth;
 
 	PROC_INFO_INC(sb, get_neighbors[h]);
 
@@ -1969,9 +1970,9 @@ static int get_neighbors(struct tree_balance *tb, int h)
 		     tb->FL[h]) ? tb->lkey[h] : B_NR_ITEMS(tb->
 								       FL[h]);
 		son_number = B_N_CHILD_NUM(tb->FL[h], child_position);
-		reiserfs_write_unlock(sb);
+		depth = reiserfs_write_unlock_nested(tb->tb_sb);
 		bh = sb_bread(sb, son_number);
-		reiserfs_write_lock(sb);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
 		if (!bh)
 			return IO_ERROR;
 		if (FILESYSTEM_CHANGED_TB(tb)) {
@@ -2009,9 +2010,9 @@ static int get_neighbors(struct tree_balance *tb, int h)
 		child_position =
 		    (bh == tb->FR[h]) ? tb->rkey[h] + 1 : 0;
 		son_number = B_N_CHILD_NUM(tb->FR[h], child_position);
-		reiserfs_write_unlock(sb);
+		depth = reiserfs_write_unlock_nested(tb->tb_sb);
 		bh = sb_bread(sb, son_number);
-		reiserfs_write_lock(sb);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
 		if (!bh)
 			return IO_ERROR;
 		if (FILESYSTEM_CHANGED_TB(tb)) {
@@ -2272,6 +2273,7 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb)
 		}
 
 		if (locked) {
+			int depth;
 #ifdef CONFIG_REISERFS_CHECK
 			repeat_counter++;
 			if ((repeat_counter % 10000) == 0) {
@@ -2286,9 +2288,9 @@ static int wait_tb_buffers_until_unlocked(struct tree_balance *tb)
 				    REPEAT_SEARCH : CARRY_ON;
 			}
 #endif
-			reiserfs_write_unlock(tb->tb_sb);
+			depth = reiserfs_write_unlock_nested(tb->tb_sb);
 			__wait_on_buffer(locked);
-			reiserfs_write_lock(tb->tb_sb);
+			reiserfs_write_lock_nested(tb->tb_sb, depth);
 			if (FILESYSTEM_CHANGED_TB(tb))
 				return REPEAT_SEARCH;
 		}
@@ -2359,9 +2361,9 @@ int fix_nodes(int op_mode, struct tree_balance *tb,
 
 	/* if it possible in indirect_to_direct conversion */
 	if (buffer_locked(tbS0)) {
-		reiserfs_write_unlock(tb->tb_sb);
+		int depth = reiserfs_write_unlock_nested(tb->tb_sb);
 		__wait_on_buffer(tbS0);
-		reiserfs_write_lock(tb->tb_sb);
+		reiserfs_write_lock_nested(tb->tb_sb, depth);
 		if (FILESYSTEM_CHANGED_TB(tb))
 			return REPEAT_SEARCH;
 	}