NFSv4: fix getacl ERANGE for some ACL buffer sizes

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 <dros@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ae0ec51dc0271ff902128e120e8b9ef79f696f1f..4e3679b25b9b5849436eb1ca2b2366a88c601f59 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4711,7 +4711,7 @@ 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,
@@ -4725,13 +4725,9 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
                .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;