[Cluster-devel] [PATCH] gfs2: Make sure FITRIM minlen is rounded up to fs block size

[Andrew Price <anprice@redhat.com>]

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>
---
 fs/gfs2/rgrp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 0fb3c01bc557..a34945cbf32a 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1415,7 +1415,8 @@ 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)
-- 
2.35.1