[68/80] NFS: Prevent 3.0 from crashing if it receives a partial layout

[Greg KH]

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>

This is a backport of critical parts of
commit 7c24d9489f "NFSv4.1: File layout only supports whole file layouts"

It prevents the file layout driver from (incorrectly) using
partial layouts, but ignores the part of the referenced commmit that
relies on additional machinery to change the LAYOUTGET request
based on layout driver.

Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxx>
Acked-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/nfs/nfs4filelayout.c |    8 ++++++++
 fs/nfs/pnfs.c           |    3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -428,6 +428,14 @@ filelayout_check_layout(struct pnfs_layo
 
 	dprintk("--> %s\n", __func__);
 
+	/* FIXME: remove this check when layout segment support is added */
+	if (lgr->range.offset != 0 ||
+	    lgr->range.length != NFS4_MAX_UINT64) {
+		dprintk("%s Only whole file layouts supported. Use MDS i/o\n",
+			__func__);
+		goto out;
+	}
+
 	if (fl->pattern_offset > lgr->range.offset) {
 		dprintk("%s pattern_offset %lld too large\n",
 				__func__, fl->pattern_offset);
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -980,7 +980,8 @@ pnfs_update_layout(struct inode *ino,
 		arg.offset -= pg_offset;
 		arg.length += pg_offset;
 	}
-	arg.length = PAGE_CACHE_ALIGN(arg.length);
+	if (arg.length != NFS4_MAX_UINT64)
+		arg.length = PAGE_CACHE_ALIGN(arg.length);
 
 	lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
 	if (!lseg && first) {


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