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

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

From: Weston Andros Adamson <d...@primarydata.com>

commit ed92d8c137b7794c2c2aa14479298b9885967607 upstream.

We're not taking into account that the space needed for the (variable
length) attr bitmap, with the result that we'd sometimes get a spurious
ERANGE when the ACL data got close to the end of a page.

Just add in an extra page to make sure.

Signed-off-by: Weston Andros Adamson <d...@primarydata.com>
Signed-off-by: J. Bruce Fields <bfie...@redhat.com>
Signed-off-by: Anna Schumaker <anna.schuma...@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/nfs/nfs4proc.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4990,7 +4990,7 @@ out:
  */
 static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t 
buflen)
 {
-       struct page *pages[NFS4ACL_MAXPAGES] = {NULL, };
+       struct page *pages[NFS4ACL_MAXPAGES + 1] = {NULL, };
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
@@ -5004,13 +5004,9 @@ static ssize_t __nfs4_get_acl_uncached(s
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
-       unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE);
+       unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE) + 1;
        int ret = -ENOMEM, i;
 
-       /* As long as we're doing a round trip to the server anyway,
-        * let's be prepared for a page of acl data. */
-       if (npages == 0)
-               npages = 1;
        if (npages > ARRAY_SIZE(pages))
                return -ERANGE;
 


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