Commit e7445ced authored Nov 08, 2018 by Andreas Gruenbacher

gfs2: Fix metadata read-ahead during truncate (2)

The previous attempt to fix for metadata read-ahead during truncate was
incorrect: for files with a height > 2 (1006989312 bytes with a block
size of 4096 bytes), read-ahead requests were not being issued for some
of the indirect blocks discovered while walking the metadata tree,
leading to significant slow-downs when deleting large files. Fix that.

In addition, only issue read-ahead requests in the first pass through
the meta-data tree, while deallocating data blocks.

Fixes: c3ce5aa9 ("gfs2: Fix metadata read-ahead during truncate")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

parent 10283ea5

fs/gfs2/bmap.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -1908,10 +1908,16 @@ static int punch_hole(struct gfs2_inode *ip, u64 offset, u64 length)
		if (ret < 0)
		goto out;

		/* issue read-ahead on metadata */
		if (mp.mp_aheight > 1) {
		for (; ret > 1; ret--) {
		metapointer_range(&mp, mp.mp_aheight - ret,
		/* On the first pass, issue read-ahead on metadata. */
		if (mp.mp_aheight > 1 && strip_h == ip->i_height - 1) {
		unsigned int height = mp.mp_aheight - 1;

		/* No read-ahead for data blocks. */
		if (mp.mp_aheight - 1 == strip_h)
		height--;

		for (; height >= mp.mp_aheight - ret; height--) {
		metapointer_range(&mp, height,
		start_list, start_aligned,
		end_list, end_aligned,
		&start, &end);