gfs2 log recovery: Full-log readaheadgfs2-log

Read the entire log into the page cache immediately instead of reading
it in chunk by chunk as required.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

3 files changed, 77 insertions, 0 deletions

diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index ffa6fea4a68ee3..10177650269ef4 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -27,6 +27,7 @@
 #include "inode.h"
 #include "log.h"
 #include "lops.h"
+#include "bmap.h"
 #include "meta_io.h"
 #include "rgrp.h"
 #include "trans.h"
@@ -327,6 +328,66 @@ int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	return 0;
 }
 
+int gfs2_readahead_extent(struct gfs2_inode *ip, unsigned int *blk)
+{
+	struct gfs2_glock *gl = ip->i_gl;
+	struct bio *bio = NULL;
+	struct buffer_head *bh = NULL;
+	int new = 0;
+	u64 dblock;
+	u32 extlen;
+	int error;
+
+	error = gfs2_extent_map(&ip->i_inode, *blk, &new, &dblock, &extlen);
+	if (error)
+		return error;
+	if (!dblock) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
+
+	while (extlen) {
+		if (!bh) {
+			bh = gfs2_getbuf(gl, dblock, CREATE);
+			if (buffer_uptodate(bh) || !trylock_buffer(bh)) {
+				brelse(bh);
+				if (bio) {
+					submit_bio(bio);
+					bio = NULL;
+				}
+				goto next_bh;
+			}
+			bh->b_end_io = end_buffer_read_sync;
+		}
+
+		if (!bio) {
+			bio = bio_alloc(GFP_NOIO, min((int)extlen, BIO_MAX_PAGES));
+			bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+			bio->bi_bdev = bh->b_bdev;
+			bio->bi_end_io = gfs2_meta_read_endio;
+			bio_set_op_attrs(bio, REQ_OP_READ, REQ_RAHEAD | REQ_META);
+		}
+
+		if (bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh)))
+			goto next_bh;
+
+		submit_bio(bio);
+		bio = NULL;
+		continue;
+
+next_bh:
+		bh = NULL;
+		(*blk)++;
+		dblock++;
+		extlen--;
+	}
+
+	if (bio)
+		submit_bio(bio);
+
+	return 0;
+}
+
 void gfs2_remove_from_journal(struct buffer_head *bh, int meta)
 {
 	struct address_space *mapping = bh->b_page->mapping;
diff --git a/fs/gfs2/meta_io.h b/fs/gfs2/meta_io.h
index 259b650e859722..d347847b38d613 100644
--- a/fs/gfs2/meta_io.h
+++ b/fs/gfs2/meta_io.h
@@ -56,6 +56,7 @@ extern void gfs2_meta_read_endio(struct bio *bio);
 extern int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
 			  int rahead, struct buffer_head **bhp);
 extern int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh);
+extern int gfs2_readahead_extent(struct gfs2_inode *ip, unsigned int *blk);
 extern struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno,
 				       int create);
 enum {
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index e7186828643c51..0f2e88d90f171b 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -83,6 +83,19 @@ submit:
 	return 0;
 }
 
+static int gfs2_readahead_journal(struct gfs2_jdesc *jd)
+{
+	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+	unsigned int blk = 0;
+
+	while (blk < jd->jd_blocks) {
+		int error = gfs2_readahead_extent(ip, &blk);
+		if (error)
+			return error;
+	}
+	return 0;
+}
+
 int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
 {
 	struct list_head *head = &jd->jd_revoke_list;
@@ -248,6 +261,8 @@ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
 	u32 blk = 0;
 	int error;
 
+	gfs2_readahead_journal(jd);
+
 	error = gfs2_map_journal_extents(sdp, jd);
 	if (error)
 		return error;