[GFS2] Fix bmap to map extents properly

This fix means that bmap will map extents of the length requested
by the VFS rather than guessing at it, or just mapping one block
at a time. The other callers of gfs2_block_map are audited to ensure
they send the correct max extent lengths (i.e. set bh->b_size correctly).
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/bmap.c

@@ -434,8 +434,7 @@ static int lookup_block(struct gfs2_inode *ip, struct buffer_head *bh,
  */
 
 static int gfs2_block_pointers(struct inode *inode, u64 lblock, int create,
-			       struct buffer_head *bh_map, struct metapath *mp,
-			       unsigned int maxlen)
+			       struct buffer_head *bh_map, struct metapath *mp)
 {
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_sbd *sdp = GFS2_SB(inode);
@@ -448,6 +447,7 @@ static int gfs2_block_pointers(struct inode *inode, u64 lblock, int create,
 	int new = 0;
 	u64 dblock = 0;
 	int boundary;
+	unsigned int maxlen = bh_map->b_size >> inode->i_blkbits;
 
 	BUG_ON(maxlen == 0);
 
@@ -541,13 +541,13 @@ static inline void bmap_unlock(struct inode *inode, int create)
 }
 
 int gfs2_block_map(struct inode *inode, u64 lblock, int create,
-		   struct buffer_head *bh, unsigned int maxlen)
+		   struct buffer_head *bh)
 {
 	struct metapath mp;
 	int ret;
 
 	bmap_lock(inode, create);
-	ret = gfs2_block_pointers(inode, lblock, create, bh, &mp, maxlen);
+	ret = gfs2_block_pointers(inode, lblock, create, bh, &mp);
 	bmap_unlock(inode, create);
 	return ret;
 }
@@ -555,7 +555,7 @@ int gfs2_block_map(struct inode *inode, u64 lblock, int create,
 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
 {
 	struct metapath mp;
-	struct buffer_head bh = { .b_state = 0, .b_blocknr = 0, .b_size = 0 };
+	struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 };
 	int ret;
 	int create = *new;
 
@@ -563,8 +563,9 @@ int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsi
 	BUG_ON(!dblock);
 	BUG_ON(!new);
 
+	bh.b_size = 1 << (inode->i_blkbits + 5);
 	bmap_lock(inode, create);
-	ret = gfs2_block_pointers(inode, lblock, create, &bh, &mp, 32);
+	ret = gfs2_block_pointers(inode, lblock, create, &bh, &mp);
 	bmap_unlock(inode, create);
 	*extlen = bh.b_size >> inode->i_blkbits;
 	*dblock = bh.b_blocknr;

fs/gfs2/bmap.h

@@ -15,7 +15,7 @@ struct gfs2_inode;
 struct page;
 
 int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
-int gfs2_block_map(struct inode *inode, u64 lblock, int create, struct buffer_head *bh, unsigned int maxlen);
+int gfs2_block_map(struct inode *inode, u64 lblock, int create, struct buffer_head *bh);
 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen);
 
 int gfs2_truncatei(struct gfs2_inode *ip, u64 size);

fs/gfs2/log.c

@@ -312,10 +312,12 @@ void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 
 static u64 log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
 {
+	struct inode *inode = sdp->sd_jdesc->jd_inode;
 	int error;
-	struct buffer_head bh_map;
+	struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
 
-	error = gfs2_block_map(sdp->sd_jdesc->jd_inode, lbn, 0, &bh_map, 1);
+	bh_map.b_size = 1 << inode->i_blkbits;
+	error = gfs2_block_map(inode, lbn, 0, &bh_map);
 	if (error || !bh_map.b_blocknr)
 		printk(KERN_INFO "error=%d, dbn=%llu lbn=%u", error, bh_map.b_blocknr, lbn);
 	gfs2_assert_withdraw(sdp, !error && bh_map.b_blocknr);

fs/gfs2/ops_address.c

@@ -65,7 +65,7 @@ static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
 int gfs2_get_block(struct inode *inode, sector_t lblock,
 	           struct buffer_head *bh_result, int create)
 {
-	return gfs2_block_map(inode, lblock, create, bh_result, 32);
+	return gfs2_block_map(inode, lblock, create, bh_result);
 }
 
 /**
@@ -83,7 +83,7 @@ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
 {
 	int error;
 
-	error = gfs2_block_map(inode, lblock, 0, bh_result, 1);
+	error = gfs2_block_map(inode, lblock, 0, bh_result);
 	if (error)
 		return error;
 	if (bh_result->b_blocknr == 0)
@@ -94,7 +94,7 @@ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
 				 struct buffer_head *bh_result, int create)
 {
-	return gfs2_block_map(inode, lblock, 0, bh_result, 32);
+	return gfs2_block_map(inode, lblock, 0, bh_result);
 }
 
 /**

fs/gfs2/quota.c

@@ -251,7 +251,7 @@ static int bh_get(struct gfs2_quota_data *qd)
 	unsigned int block, offset;
 	struct buffer_head *bh;
 	int error;
-	struct buffer_head bh_map;
+	struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
 
 	mutex_lock(&sdp->sd_quota_mutex);
 
@@ -263,7 +263,8 @@ static int bh_get(struct gfs2_quota_data *qd)
 	block = qd->qd_slot / sdp->sd_qc_per_block;
 	offset = qd->qd_slot % sdp->sd_qc_per_block;;
 
-	error = gfs2_block_map(&ip->i_inode, block, 0, &bh_map, 1);
+	bh_map.b_size = 1 << ip->i_inode.i_blkbits;
+	error = gfs2_block_map(&ip->i_inode, block, 0, &bh_map);
 	if (error)
 		goto fail;
 	error = gfs2_meta_read(ip->i_gl, bh_map.b_blocknr, DIO_WAIT, &bh);

fs/gfs2/recovery.c

@@ -372,11 +372,12 @@ static int clean_journal(struct gfs2_jdesc *jd, struct gfs2_log_header *head)
 	u32 hash;
 	struct buffer_head *bh;
 	int error;
-	struct buffer_head bh_map;
+	struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
 
 	lblock = head->lh_blkno;
 	gfs2_replay_incr_blk(sdp, &lblock);
-	error = gfs2_block_map(&ip->i_inode, lblock, 0, &bh_map, 1);
+	bh_map.b_size = 1 << ip->i_inode.i_blkbits;
+	error = gfs2_block_map(&ip->i_inode, lblock, 0, &bh_map);
 	if (error)
 		return error;
 	if (!bh_map.b_blocknr) {