gfs2: changes to gfs2_log_XXX_bio

Change gfs2_log_XXX_bio family of functions so they can be used
with different bios, not just sdp->sd_log_bio.

This patch also contains some clean up suggested by Andreas.
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/log.c

@@ -734,7 +734,7 @@ void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
 	lh->lh_crc = cpu_to_be32(crc);
 
 	gfs2_log_write(sdp, page, sb->s_blocksize, 0, addr);
-	gfs2_log_flush_bio(sdp, REQ_OP_WRITE, op_flags);
+	gfs2_log_submit_bio(&sdp->sd_log_bio, REQ_OP_WRITE, op_flags);
 	log_flush_wait(sdp);
 }
 
@@ -811,7 +811,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 
 	gfs2_ordered_write(sdp);
 	lops_before_commit(sdp, tr);
-	gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
+	gfs2_log_submit_bio(&sdp->sd_log_bio, REQ_OP_WRITE, 0);
 
 	if (sdp->sd_log_head != sdp->sd_log_flush_head) {
 		log_flush_wait(sdp);

fs/gfs2/lops.c

@@ -228,8 +228,8 @@ static void gfs2_end_log_write(struct bio *bio)
 }
 
 /**
- * gfs2_log_flush_bio - Submit any pending log bio
- * @sdp: The superblock
+ * gfs2_log_submit_bio - Submit any pending log bio
+ * @biop: Address of the bio pointer
  * @op: REQ_OP
  * @op_flags: req_flag_bits
  *
@@ -237,74 +237,78 @@ static void gfs2_end_log_write(struct bio *bio)
  * there is no pending bio, then this is a no-op.
  */
 
-void gfs2_log_flush_bio(struct gfs2_sbd *sdp, int op, int op_flags)
+void gfs2_log_submit_bio(struct bio **biop, int op, int op_flags)
 {
-	if (sdp->sd_log_bio) {
+	struct bio *bio = *biop;
+	if (bio) {
+		struct gfs2_sbd *sdp = bio->bi_private;
 		atomic_inc(&sdp->sd_log_in_flight);
-		bio_set_op_attrs(sdp->sd_log_bio, op, op_flags);
-		submit_bio(sdp->sd_log_bio);
-		sdp->sd_log_bio = NULL;
+		bio_set_op_attrs(bio, op, op_flags);
+		submit_bio(bio);
+		*biop = NULL;
 	}
 }
 
 /**
- * gfs2_log_alloc_bio - Allocate a new bio for log writing
- * @sdp: The superblock
- * @blkno: The next device block number we want to write to
+ * gfs2_log_alloc_bio - Allocate a bio
+ * @sdp: The super block
+ * @blkno: The device block number we want to write to
+ * @end_io: The bi_end_io callback
  *
- * This should never be called when there is a cached bio in the
- * super block. When it returns, there will be a cached bio in the
- * super block which will have as many bio_vecs as the device is
- * happy to handle.
+ * Allocate a new bio, initialize it with the given parameters and return it.
  *
- * Returns: Newly allocated bio
+ * Returns: The newly allocated bio
  */
 
-static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno)
+static struct bio *gfs2_log_alloc_bio(struct gfs2_sbd *sdp, u64 blkno,
+				      bio_end_io_t *end_io)
 {
 	struct super_block *sb = sdp->sd_vfs;
-	struct bio *bio;
-
-	BUG_ON(sdp->sd_log_bio);
+	struct bio *bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
 
-	bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
 	bio->bi_iter.bi_sector = blkno * (sb->s_blocksize >> 9);
 	bio_set_dev(bio, sb->s_bdev);
-	bio->bi_end_io = gfs2_end_log_write;
+	bio->bi_end_io = end_io;
 	bio->bi_private = sdp;
 
-	sdp->sd_log_bio = bio;
-
 	return bio;
 }
 
 /**
  * gfs2_log_get_bio - Get cached log bio, or allocate a new one
- * @sdp: The superblock
+ * @sdp: The super block
  * @blkno: The device block number we want to write to
+ * @bio: The bio to get or allocate
+ * @op: REQ_OP
+ * @end_io: The bi_end_io callback
+ * @flush: Always flush the current bio and allocate a new one?
  *
  * If there is a cached bio, then if the next block number is sequential
  * with the previous one, return it, otherwise flush the bio to the
- * device. If there is not a cached bio, or we just flushed it, then
+ * device. If there is no cached bio, or we just flushed it, then
  * allocate a new one.
  *
  * Returns: The bio to use for log writes
  */
 
-static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno)
+static struct bio *gfs2_log_get_bio(struct gfs2_sbd *sdp, u64 blkno,
+				    struct bio **biop, int op,
+				    bio_end_io_t *end_io, bool flush)
 {
-	struct bio *bio = sdp->sd_log_bio;
-	u64 nblk;
+	struct bio *bio = *biop;
 
 	if (bio) {
+		u64 nblk;
+
 		nblk = bio_end_sector(bio);
 		nblk >>= sdp->sd_fsb2bb_shift;
-		if (blkno == nblk)
+		if (blkno == nblk && !flush)
 			return bio;
-		gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
+		gfs2_log_submit_bio(biop, op, 0);
 	}
 
-	return gfs2_log_alloc_bio(sdp, blkno);
+	*biop = gfs2_log_alloc_bio(sdp, blkno, end_io);
+	return *biop;
 }
 
 /**
@@ -326,11 +330,12 @@ void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
 	struct bio *bio;
 	int ret;
 
-	bio = gfs2_log_get_bio(sdp, blkno);
+	bio = gfs2_log_get_bio(sdp, blkno, &sdp->sd_log_bio, REQ_OP_WRITE,
+			       gfs2_end_log_write, false);
 	ret = bio_add_page(bio, page, size, offset);
 	if (ret == 0) {
-		gfs2_log_flush_bio(sdp, REQ_OP_WRITE, 0);
-		bio = gfs2_log_alloc_bio(sdp, blkno);
+		bio = gfs2_log_get_bio(sdp, blkno, &sdp->sd_log_bio,
+				       REQ_OP_WRITE, gfs2_end_log_write, true);
 		ret = bio_add_page(bio, page, size, offset);
 		WARN_ON(ret == 0);
 	}

fs/gfs2/lops.h

@@ -30,7 +30,7 @@ extern u64 gfs2_log_bmap(struct gfs2_sbd *sdp);
 extern void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
 			   unsigned size, unsigned offset, u64 blkno);
 extern void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page);
-extern void gfs2_log_flush_bio(struct gfs2_sbd *sdp, int op, int op_flags);
+extern void gfs2_log_submit_bio(struct bio **biop, int op, int op_flags);
 extern void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh);
 
 static inline unsigned int buf_limit(struct gfs2_sbd *sdp)