gfs2: Fix loop in gfs2_rbm_find

Andreas Gruenbacher · Andreas Gruenbacher · commit 2d29f6b96d8f · 2018-12-12T12:31:40.000+01:00
Fix the resource group wrap-around logic in gfs2_rbm_find that commit e579ed4 broke. The bug can lead to unnecessary repeated scanning of the same bitmaps; there is a risk that future changes will turn this into an endless loop. Fixes: e579ed4 ("GFS2: Introduce rbm field bii") Cc: stable@vger.kernel.org # v3.13+ Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
@@ -1780,9 +1780,9 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 			goto next_iter;
 		}
 		if (ret == -E2BIG) {
+			n += rbm->bii - initial_bii;
 			rbm->bii = 0;
 			rbm->offset = 0;
-			n += (rbm->bii - initial_bii);
 			goto res_covered_end_of_rgrp;
 		}
 		return ret;

Original file line number	Diff line number	Diff line change
`@@ -1780,9 +1780,9 @@ static int gfs2_rbm_find(struct gfs2_rbm rbm, u8 state, u32 minext,`
`1780`	`1780`	`goto next_iter;`
`1781`	`1781`	`}`
`1782`	`1782`	`if (ret == -E2BIG) {`
	`1783`	`+ n += rbm->bii - initial_bii;`
`1783`	`1784`	`rbm->bii = 0;`
`1784`	`1785`	`rbm->offset = 0;`
`1785`		`- n += (rbm->bii - initial_bii);`
`1786`	`1786`	`goto res_covered_end_of_rgrp;`
`1787`	`1787`	`}`
`1788`	`1788`	`return ret;`