gfs2: Make sure FITRIM minlen is rounded up to fs block size

Per fstrim(8) we must round up the minlen argument to the fs block size.
The current calculation doesn't take into account devices that have a
discard granularity and requested minlen less than 1 fs block, so the
value can get shifted away to zero in the translation to fs blocks.

The zero minlen passed to gfs2_rgrp_send_discards() then allows
sb_issue_discard() to be called with nr_sects == 0 which returns -EINVAL
and results in gfs2_rgrp_send_discards() returning -EIO.

Make sure minlen is never < 1 fs block by taking the max of the
requested minlen and the fs block size before comparing to the device's
discard granularity and shifting to fs blocks.

Fixes: 076f0faa764ab ("GFS2: Fix FITRIM argument handling")
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 9df8a84f85a649bf82c83c7a4d85d1c5f8c8cd00..801ad9f4f2bef9cc4b0ec335cc794a6c572d733f 100644 (file)
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1417,7 +1417,8 @@ int gfs2_fitrim(struct file *filp, void __user *argp)
 
        start = r.start >> bs_shift;
        end = start + (r.len >> bs_shift);
-       minlen = max_t(u64, r.minlen,
+       minlen = max_t(u64, r.minlen, sdp->sd_sb.sb_bsize);
+       minlen = max_t(u64, minlen,
                       q->limits.discard_granularity) >> bs_shift;
 
        if (end <= start || minlen > sdp->sd_max_rg_data)