[PATCH v2 1/3] NFSv4.1/pnfs: Don't ask for a read layout for an empty file.

[PATCH v2 1/3] NFSv4.1/pnfs: Don't ask for a read layout for an empty file.

[Trond Myklebust]

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/pnfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 4eec540de9ea..c4f918eca3d2 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1494,6 +1494,9 @@ 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

[PATCH v2 2/3] NFSv4.1/pnfs: Handle LAYOUTGET return values correctly

[Trond Myklebust]

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 <trond.myklebust@primarydata.com>
---
 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 366b81c185f6..51c7164abd1a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7781,10 +7781,19 @@ 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).
@@ -7840,6 +7849,10 @@ 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

[PATCH v2 3/3] NFSv4.1/pNFS: Don't request a minimal read layout beyond the end of file

[Trond Myklebust]

If we have a read layout, then sanity check the minimal layout length
so that it does not extend beyond the end of file.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/pnfs.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index c4f918eca3d2..ba1246433794 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -868,6 +868,7 @@ send_layoutget(struct pnfs_layout_hdr *lo,
 	struct nfs_server *server = NFS_SERVER(ino);
 	struct nfs4_layoutget *lgp;
 	struct pnfs_layout_segment *lseg;
+	loff_t i_size;
 
 	dprintk("--> %s\n", __func__);
 
@@ -875,9 +876,17 @@ send_layoutget(struct pnfs_layout_hdr *lo,
 	if (lgp == NULL)
 		return NULL;
 
+	i_size = i_size_read(ino);
+
 	lgp->args.minlength = PAGE_CACHE_SIZE;
 	if (lgp->args.minlength > range->length)
 		lgp->args.minlength = range->length;
+	if (range->iomode == IOMODE_READ) {
+		if (range->offset >= i_size)
+			lgp->args.minlength = 0;
+		else if (i_size - range->offset < lgp->args.minlength)
+			lgp->args.minlength = i_size - range->offset;
+	}
 	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
 	lgp->args.range = *range;
 	lgp->args.type = server->pnfs_curr_ld->id;
-- 
2.4.3