GFS2: speed up delete/unlink performance for large files

This patch improves the performance of delete/unlink
operations in a GFS2 file system where the files are large
by adding a layer of metadata read-ahead for indirect blocks.
Mileage will vary, but on my system, deleting an 8.6G file
dropped from 22 seconds to about 4.5 seconds.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 22ad413213ca5b64d91d7fff64063c6fdd93028d..834cd9442a1d08a96b1298a565b297643609fb9b 100644 (file)
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -831,7 +831,7 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
 {
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head *bh = NULL;
-       __be64 *top, *bottom;
+       __be64 *top, *bottom, *t2;
        u64 bn;
        int error;
        int mh_size = sizeof(struct gfs2_meta_header);
@@ -859,7 +859,27 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
        if (error)
                goto out;
 
-       if (height < ip->i_height - 1)
+       if (height < ip->i_height - 1) {
+               struct buffer_head *rabh;
+
+               for (t2 = top; t2 < bottom; t2++, first = 0) {
+                       if (!*t2)
+                               continue;
+
+                       bn = be64_to_cpu(*t2);
+                       rabh = gfs2_getbuf(ip->i_gl, bn, CREATE);
+                       if (trylock_buffer(rabh)) {
+                               if (buffer_uptodate(rabh)) {
+                                       unlock_buffer(rabh);
+                                       brelse(rabh);
+                                       continue;
+                               }
+                               rabh->b_end_io = end_buffer_read_sync;
+                               submit_bh(READA | REQ_META, rabh);
+                               continue;
+                       }
+                       brelse(rabh);
+               }
                for (; top < bottom; top++, first = 0) {
                        if (!*top)
                                continue;
@@ -871,7 +891,7 @@ static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
                        if (error)
                                break;
                }
-
+       }
 out:
        brelse(bh);
        return error;