2015-08-31 08:32:51

by Trond Myklebust

Subject: [PATCH 1/2] NFSv4.1/pnfs: Don't ask for a read layout for an empty file.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/pnfs.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 838e865de8a5..9c32c043ab24 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1453,6 +1453,9 @@ pnfs_update_layout(struct inode *ino,
if (!pnfs_enabled_sb(NFS_SERVER(ino)))
goto out;

+ if (iomode == IOMODE_READ && i_size_read(ino) == 0)
+ goto out;
+
if (pnfs_within_mdsthreshold(ctx, ino, iomode))
goto out;

--
2.4.3

2015-08-31 08:32:52

by Trond Myklebust

Subject: [PATCH 2/2] NFSv4.1/pnfs: Handle LAYOUTGET return values correctly

According to RFC5661 section 18.43.3, if the server cannot satisfy
the loga_minlength argument to LAYOUTGET, there are 2 cases:
1) If loga_minlength == 0, it returns NFS4ERR_LAYOUTTRYLATER
2) If loga_minlength != 0, it returns NFS4ERR_BADLAYOUT

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/nfs4proc.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f544cde8c3eb..e3b8c9e2f977 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7817,10 +7817,19 @@ static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
case 0:
goto out;
/*
+ * NFS4ERR_BADLAYOUT means the MDS cannot return a layout of
+ * length lgp->args.minlength != 0 (see RFC5661 section 18.43.3).
+ */
+ case -NFS4ERR_BADLAYOUT:
+ goto out_overflow;
+ /*
* NFS4ERR_LAYOUTTRYLATER is a conflict with another client
- * (or clients) writing to the same RAID stripe
+ * (or clients) writing to the same RAID stripe except when
+ * the minlength argument is 0 (see RFC5661 section 18.43.3).
*/
case -NFS4ERR_LAYOUTTRYLATER:
+ if (lgp->args.minlength == 0)
+ goto out_overflow;
/*
* NFS4ERR_RECALLCONFLICT is when conflict with self (must recall
* existing layout before getting a new one).
@@ -7876,6 +7885,10 @@ static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
rpc_restart_call_prepare(task);
out:
dprintk("<-- %s\n", __func__);
+ return;
+out_overflow:
+ task->tk_status = -EOVERFLOW;
+ goto out;
}

static size_t max_response_pages(struct nfs_server *server)
--
2.4.3