gfs2: Extended attribute readahead

When gfs2 allocates an inode and its extended attribute block next to
each other at inode create time, the inode's directory entry indicates
that in de_rahead.  In that case, we can readahead the extended
attribute block when we read in the inode.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/dir.c

@@ -108,7 +108,7 @@ static int gfs2_dir_get_existing_buffer(struct gfs2_inode *ip, u64 block,
 	struct buffer_head *bh;
 	int error;
 
-	error = gfs2_meta_read(ip->i_gl, block, DIO_WAIT, &bh);
+	error = gfs2_meta_read(ip->i_gl, block, DIO_WAIT, 0, &bh);
 	if (error)
 		return error;
 	if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_JD)) {
@@ -305,7 +305,7 @@ static int gfs2_dir_read_data(struct gfs2_inode *ip, __be64 *buf,
 			BUG_ON(extlen < 1);
 			bh = gfs2_meta_ra(ip->i_gl, dblock, extlen);
 		} else {
-			error = gfs2_meta_read(ip->i_gl, dblock, DIO_WAIT, &bh);
+			error = gfs2_meta_read(ip->i_gl, dblock, DIO_WAIT, 0, &bh);
 			if (error)
 				goto fail;
 		}
@@ -723,7 +723,7 @@ static int get_leaf(struct gfs2_inode *dip, u64 leaf_no,
 {
 	int error;
 
-	error = gfs2_meta_read(dip->i_gl, leaf_no, DIO_WAIT, bhp);
+	error = gfs2_meta_read(dip->i_gl, leaf_no, DIO_WAIT, 0, bhp);
 	if (!error && gfs2_metatype_check(GFS2_SB(&dip->i_inode), *bhp, GFS2_METATYPE_LF)) {
 		/* pr_info("block num=%llu\n", leaf_no); */
 		error = -EIO;
@@ -1560,15 +1560,22 @@ struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name,
 
 	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
 	if (dent) {
+		struct inode *inode;
+		u16 rahead;
+
 		if (IS_ERR(dent))
 			return ERR_CAST(dent);
 		dtype = be16_to_cpu(dent->de_type);
+		rahead = be16_to_cpu(dent->de_rahead);
 		addr = be64_to_cpu(dent->de_inum.no_addr);
 		formal_ino = be64_to_cpu(dent->de_inum.no_formal_ino);
 		brelse(bh);
 		if (fail_on_exist)
 			return ERR_PTR(-EEXIST);
-		return gfs2_inode_lookup(dir->i_sb, dtype, addr, formal_ino, 0);
+		inode = gfs2_inode_lookup(dir->i_sb, dtype, addr, formal_ino, 0);
+		if (!IS_ERR(inode))
+			GFS2_I(inode)->i_rahead = rahead;
+		return inode;
 	}
 	return ERR_PTR(-ENOENT);
 }

fs/gfs2/incore.h

@@ -402,6 +402,7 @@ struct gfs2_inode {
 	u32 i_diskflags;
 	u8 i_height;
 	u8 i_depth;
+	u16 i_rahead;
 };
 
 /*

fs/gfs2/meta_io.c

@@ -187,6 +187,21 @@ struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
 	return bh;
 }
 
+static void gfs2_meta_readahead(struct gfs2_glock *gl, u64 blkno)
+{
+	struct buffer_head *bh;
+
+	bh = gfs2_getbuf(gl, blkno, 1);
+	lock_buffer(bh);
+	if (buffer_uptodate(bh)) {
+		unlock_buffer(bh);
+		brelse(bh);
+		return;
+	}
+	bh->b_end_io = end_buffer_read_sync;
+	submit_bh(READA | REQ_META | REQ_PRIO, bh);
+}
+
 /**
  * gfs2_meta_read - Read a block from disk
  * @gl: The glock covering the block
@@ -198,7 +213,7 @@ struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
  */
 
 int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
-		   struct buffer_head **bhp)
+		   int rahead, struct buffer_head **bhp)
 {
 	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 	struct buffer_head *bh;
@@ -213,11 +228,15 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 	lock_buffer(bh);
 	if (buffer_uptodate(bh)) {
 		unlock_buffer(bh);
+		if (rahead)
+			gfs2_meta_readahead(gl, blkno + 1);
 		return 0;
 	}
 	bh->b_end_io = end_buffer_read_sync;
 	get_bh(bh);
 	submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
+	if (rahead)
+		gfs2_meta_readahead(gl, blkno + 1);
 	if (!(flags & DIO_WAIT))
 		return 0;
 
@@ -341,8 +360,12 @@ int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
 	struct buffer_head *bh;
 	int ret = 0;
 	u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
+	int rahead = 0;
+
+	if (num == ip->i_no_addr)
+		rahead = ip->i_rahead;
 
-	ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
+	ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh);
 	if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
 		brelse(bh);
 		ret = -EIO;

fs/gfs2/meta_io.h

@@ -53,7 +53,7 @@ static inline struct gfs2_sbd *gfs2_mapping2sbd(struct address_space *mapping)
 
 extern struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno);
 extern int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
-			  struct buffer_head **bhp);
+			  int rahead, struct buffer_head **bhp);
 extern int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh);
 extern struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno,
 				       int create);

fs/gfs2/quota.c

@@ -388,7 +388,7 @@ static int bh_get(struct gfs2_quota_data *qd)
 	error = gfs2_block_map(&ip->i_inode, block, &bh_map, 0);
 	if (error)
 		goto fail;
-	error = gfs2_meta_read(ip->i_gl, bh_map.b_blocknr, DIO_WAIT, &bh);
+	error = gfs2_meta_read(ip->i_gl, bh_map.b_blocknr, DIO_WAIT, 0, &bh);
 	if (error)
 		goto fail;
 	error = -EIO;

fs/gfs2/rgrp.c

@@ -1158,7 +1158,7 @@ static int gfs2_rgrp_bh_get(struct gfs2_rgrpd *rgd)
 
 	for (x = 0; x < length; x++) {
 		bi = rgd->rd_bits + x;
-		error = gfs2_meta_read(gl, rgd->rd_addr + x, 0, &bi->bi_bh);
+		error = gfs2_meta_read(gl, rgd->rd_addr + x, 0, 0, &bi->bi_bh);
 		if (error)
 			goto fail;
 	}

fs/gfs2/super.c

@@ -1633,6 +1633,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
 		ip->i_gl = NULL;
 		ip->i_rgd = NULL;
 		ip->i_res = NULL;
+		ip->i_rahead = 0;
 	}
 	return &ip->i_inode;
 }

fs/gfs2/xattr.c

@@ -119,7 +119,7 @@ static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
 	__be64 *eablk, *end;
 	int error;
 
-	error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, &bh);
+	error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0, &bh);
 	if (error)
 		return error;
 
@@ -143,7 +143,7 @@ static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
 			break;
 		bn = be64_to_cpu(*eablk);
 
-		error = gfs2_meta_read(ip->i_gl, bn, DIO_WAIT, &eabh);
+		error = gfs2_meta_read(ip->i_gl, bn, DIO_WAIT, 0, &eabh);
 		if (error)
 			break;
 		error = ea_foreach_i(ip, eabh, ea_call, data);
@@ -477,7 +477,7 @@ static int gfs2_iter_unstuffed(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
 		return -ENOMEM;
 
 	for (x = 0; x < nptrs; x++) {
-		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0,
+		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0, 0,
 				       bh + x);
 		if (error) {
 			while (x--)
@@ -977,7 +977,7 @@ static int ea_set_block(struct gfs2_inode *ip, struct gfs2_ea_request *er,
 	if (ip->i_diskflags & GFS2_DIF_EA_INDIRECT) {
 		__be64 *end;
 
-		error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT,
+		error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0,
 				       &indbh);
 		if (error)
 			return error;
@@ -1303,7 +1303,7 @@ static int ea_dealloc_indirect(struct gfs2_inode *ip)
 
 	memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
 
-	error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, &indbh);
+	error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0, &indbh);
 	if (error)
 		return error;