nfsd: notify_change needs elevated write count
commit 9f67f189939eccaa54f3d2c9cf10788abaf2d584 upstream.
Looks like this bug has been here since these write counts were
introduced, not sure why it was just noticed now.
Thanks also to Jan Kara for pointing out the problem.
Reported-by: Matthew Rahtz <mrahtz@rapitasystems.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 026a873..6383062 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -406,6 +406,7 @@
umode_t ftype = 0;
__be32 err;
int host_err;
+ bool get_write_count;
int size_change = 0;
if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
@@ -413,10 +414,18 @@
if (iap->ia_valid & ATTR_SIZE)
ftype = S_IFREG;
+ /* Callers that do fh_verify should do the fh_want_write: */
+ get_write_count = !fhp->fh_dentry;
+
/* Get inode */
err = fh_verify(rqstp, fhp, ftype, accmode);
if (err)
goto out;
+ if (get_write_count) {
+ host_err = fh_want_write(fhp);
+ if (host_err)
+ return nfserrno(host_err);
+ }
dentry = fhp->fh_dentry;
inode = dentry->d_inode;