gfs2: Extended attribute readahead optimization
Instead of submitting a READ_SYNC bio for the inode and a READA bio for the inode's extended attributes through submit_bh, submit a single READ_SYNC bio for both through submit_bio when possible. This can be more efficient on some kinds of block devices. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
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c8d5770384
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39b0555f7a
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@ -187,19 +187,50 @@ struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
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return bh;
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}
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static void gfs2_meta_readahead(struct gfs2_glock *gl, u64 blkno)
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static void gfs2_meta_read_endio(struct bio *bio)
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{
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struct buffer_head *bh;
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struct bio_vec *bvec;
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int i;
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bh = gfs2_getbuf(gl, blkno, 1);
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lock_buffer(bh);
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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brelse(bh);
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return;
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bio_for_each_segment_all(bvec, bio, i) {
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struct page *page = bvec->bv_page;
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struct buffer_head *bh = page_buffers(page);
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unsigned int len = bvec->bv_len;
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while (bh_offset(bh) < bvec->bv_offset)
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bh = bh->b_this_page;
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do {
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struct buffer_head *next = bh->b_this_page;
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len -= bh->b_size;
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bh->b_end_io(bh, !bio->bi_error);
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bh = next;
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} while (bh && len);
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}
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bh->b_end_io = end_buffer_read_sync;
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submit_bh(READA | REQ_META | REQ_PRIO, bh);
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bio_put(bio);
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}
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/*
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* Submit several consecutive buffer head I/O requests as a single bio I/O
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* request. (See submit_bh_wbc.)
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*/
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static void gfs2_submit_bhs(int rw, struct buffer_head *bhs[], int num)
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{
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struct buffer_head *bh = bhs[0];
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struct bio *bio;
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int i;
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if (!num)
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return;
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bio = bio_alloc(GFP_NOIO, num);
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bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
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bio->bi_bdev = bh->b_bdev;
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for (i = 0; i < num; i++) {
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bh = bhs[i];
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bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
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}
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bio->bi_end_io = gfs2_meta_read_endio;
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submit_bio(rw, bio);
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}
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/**
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@ -216,7 +247,8 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
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int rahead, struct buffer_head **bhp)
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{
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struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
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struct buffer_head *bh;
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struct buffer_head *bh, *bhs[2];
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int num = 0;
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if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
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*bhp = NULL;
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@ -228,18 +260,31 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
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lock_buffer(bh);
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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if (rahead)
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gfs2_meta_readahead(gl, blkno + 1);
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return 0;
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flags &= ~DIO_WAIT;
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} else {
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bh->b_end_io = end_buffer_read_sync;
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get_bh(bh);
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bhs[num++] = bh;
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}
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bh->b_end_io = end_buffer_read_sync;
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get_bh(bh);
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submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
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if (rahead)
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gfs2_meta_readahead(gl, blkno + 1);
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if (rahead) {
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bh = gfs2_getbuf(gl, blkno + 1, CREATE);
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lock_buffer(bh);
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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brelse(bh);
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} else {
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bh->b_end_io = end_buffer_read_sync;
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bhs[num++] = bh;
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}
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}
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gfs2_submit_bhs(READ_SYNC | REQ_META | REQ_PRIO, bhs, num);
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if (!(flags & DIO_WAIT))
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return 0;
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bh = *bhp;
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wait_on_buffer(bh);
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if (unlikely(!buffer_uptodate(bh))) {
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struct gfs2_trans *tr = current->journal_info;
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