* [PATCH] ceph: clamp length of a read to CEPH_MSG_MAX_DATA_LEN
@ 2021-04-23 18:52 Jeff Layton
0 siblings, 0 replies; only message in thread
From: Jeff Layton @ 2021-04-23 18:52 UTC (permalink / raw)
To: ceph-devel
Cc: idryomov, xiublu, dhowells, linux-cachefs, linux-fsdevel, willy,
lhenriques
There's a hard limit on how large a read we can do from the OSD, defined
as CEPH_MSG_MAX_DATA_LEN (currently, 64M). It's possible to create a
file that is backed by larger objects than that (and indeed, xfstest
ceph/001 does just that).
Ensure we clamp the final length of a read to CEPH_MSG_MAX_DATA_LEN.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ceph/addr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
I'm likely going to fold this patch into the one that introduces
ceph_netfs_issue_op, so we don't have a regression in the series.
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 9939100f9f9d..ba459b15604d 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -212,7 +212,7 @@ static bool ceph_netfs_clamp_length(struct netfs_read_subrequest *subreq)
/* Truncate the extent at the end of the current block */
ceph_calc_file_object_mapping(&ci->i_layout, subreq->start, subreq->len,
&objno, &objoff, &xlen);
- subreq->len = xlen;
+ subreq->len = min(xlen, (u32)CEPH_MSG_MAX_DATA_LEN);
return true;
}
--
2.31.1
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