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>

3 files changed, 42 insertions, 37 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 99dd58694ba1..e7c6e9fc62b5 100644
--- a/fs/gfs2/log.c
+++ b/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);
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 4c7069b8f3c1..2295042bc625 100644
--- a/fs/gfs2/lops.c
+++ b/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;
+        struct bio *bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
 
-        BUG_ON(sdp->sd_log_bio);
-
-        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);
         }
diff --git a/fs/gfs2/lops.h b/fs/gfs2/lops.h
index e4949394f054..711c4d89c063 100644
--- a/fs/gfs2/lops.h
+++ b/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)