[Ocfs2-devel] [PATCH] remove ocfs2_write_blocks

[Christoph Hellwig <hch@lst.de>]

we only need ocfs2_write_block because there's never more than one
buffer written.

Also remove lots of useless checks and replace the useful ones with
BUG_ON.

While we're at it, can someone please audit the buffer_head end_io
handlers in ocfs?  comparing them to the generic ones in fs/buffer.c
the buffered I/O in ocfs seems to lack grabbing a reference for the
duration of the I/O.  It might in fact be possible to just use the
generic completetion handlers.


Index: fs/ocfs2/buffer_head_io.c
===================================================================
--- fs/ocfs2/buffer_head_io.c	(revision 2593)
+++ fs/ocfs2/buffer_head_io.c	(working copy)
@@ -52,21 +52,16 @@
 	unlock_buffer(bh);
 }
 
-int ocfs2_write_blocks(ocfs2_super *osb, struct buffer_head *bhs[],
-		       int nr, struct inode *inode)
+int ocfs2_write_block(ocfs2_super *osb, struct buffer_head *bh,
+				    struct inode *inode)
 {
 	int status = 0;
-	int i;
-	struct buffer_head *bh;
 
-	mlog_entry("(bh[0]->b_blocknr = %llu, nr=%d, inode=%p)\n",
-		   (unsigned long long)bhs[0]->b_blocknr, nr, inode);
+	mlog_entry("(bh->b_blocknr = %llu, inode=%p)\n",
+		   (unsigned long long)bh->b_blocknr, inode);
 
-	if (osb == NULL || osb->sb == NULL || bhs == NULL) {
-		status = -EINVAL;
-		mlog_errno(status);
-		goto bail;
-	}
+	BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
+	BUG_ON(buffer_jbd(bh));
 
 	/* No need to check for a soft readonly file system here. non
 	 * journalled writes are only ever done on system files which
@@ -76,70 +71,34 @@
 		goto bail;
 	}
 
-	if (inode)
-		down(&OCFS2_I(inode)->ip_io_sem);
-	for (i = 0 ; i < nr ; i++) {
-		bh = bhs[i];
-		if (bh == NULL) {
-			if (inode)
-				up(&OCFS2_I(inode)->ip_io_sem);
-			status = -EIO;
-			mlog_errno(status);
-			goto bail;
-		}
+	down(&OCFS2_I(inode)->ip_io_sem);
 
-		if (unlikely(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO)) {
-			BUG();
-			status = -EIO;
-			mlog_errno(status);
-			goto bail;
-		}
+	lock_buffer(bh);
+	set_buffer_uptodate(bh);
 
-		if (unlikely(buffer_jbd(bh))) {
-			/* What are you thinking?! */
-			mlog(ML_ERROR, "trying to write a jbd managed bh "
-				       "(blocknr = %llu), nr=%d\n",
-			     (unsigned long long)bh->b_blocknr, nr);
-			BUG();
-		}
+	/* remove from dirty list before I/O. */
+	clear_buffer_dirty(bh);
 
-		lock_buffer(bh);
+	bh->b_end_io = ocfs2_end_buffer_io_sync;
+	submit_bh(WRITE, bh);
 
-		set_buffer_uptodate(bh);
+	wait_on_buffer(bh);
 
-		/* remove from dirty list before I/O. */
-		clear_buffer_dirty(bh);
-
-		bh->b_end_io = ocfs2_end_buffer_io_sync;
-		submit_bh(WRITE, bh);
+	if (buffer_uptodate(bh))
+		ocfs2_set_buffer_uptodate(inode, bh);
+	else {
+		/* Status won't be cleared from here on out,
+		 * so we can safely record this and loop back
+		 * to cleanup the other buffers. Don't need to
+		 * remove the clustered uptodate information
+		 * for this bh as it's not marked locally
+		 * uptodate. */
+		status = -EIO;
+		brelse(bh);
 	}
 
-	for (i = (nr - 1) ; i >= 0; i--) {
-		bh = bhs[i];
-
-		wait_on_buffer(bh);
-
-		if (!buffer_uptodate(bh)) {
-			/* Status won't be cleared from here on out,
-			 * so we can safely record this and loop back
-			 * to cleanup the other buffers. Don't need to
-			 * remove the clustered uptodate information
-			 * for this bh as it's not marked locally
-			 * uptodate. */
-			status = -EIO;
-			brelse(bh);
-			bhs[i] = NULL;
-			continue;
-		}
-
-		if (inode)
-			ocfs2_set_buffer_uptodate(inode, bh);
-	}
-	if (inode)
-		up(&OCFS2_I(inode)->ip_io_sem);
-
-bail:
-
+	up(&OCFS2_I(inode)->ip_io_sem);
+ bail:
 	mlog_exit(status);
 	return status;
 }
Index: fs/ocfs2/buffer_head_io.h
===================================================================
--- fs/ocfs2/buffer_head_io.h	(revision 2593)
+++ fs/ocfs2/buffer_head_io.h	(working copy)
@@ -32,19 +32,13 @@
 			     int uptodate);
 
 /* Yosh made me do it. */
-static inline int ocfs2_write_block(ocfs2_super         *osb,
-				    struct buffer_head  *bh,
-				    struct inode        *inode);
 static inline int ocfs2_read_block(ocfs2_super          *osb,
 				   u64                  off,
 				   struct buffer_head **bh,
 				   int                  flags,
 				   struct inode        *inode);
 
-int ocfs2_write_blocks(ocfs2_super          *osb,
-		       struct buffer_head  *bh[],
-		       int                  nr,
-		       struct inode        *inode);
+int ocfs2_write_block(ocfs2_super *, struct buffer_head *, struct inode *);
 int ocfs2_read_blocks(ocfs2_super          *osb,
 		      u64                  block,
 		      int                  nr,
@@ -56,16 +50,6 @@
 #define OCFS2_BH_CACHED            1
 #define OCFS2_BH_READAHEAD         8	/* use this to pass READA down to submit_bh */
 
-static inline int ocfs2_write_block(ocfs2_super * osb, struct buffer_head *bh,
-				    struct inode *inode)
-{
-	int status;
-
-	status = ocfs2_write_blocks(osb, &bh, 1, inode);
-
-	return status;
-}
-
 static inline int ocfs2_read_block(ocfs2_super * osb, u64 off,
 				   struct buffer_head **bh, int flags,
 				   struct inode *inode)