Commit 3111784b authored Jul 25, 2018 by piaojun Committed by Dominique Martinet Aug 13, 2018

fs/9p/xattr.c: catch the error of p9_client_clunk when setting xattr failed

In my testing, v9fs_fid_xattr_set will return successfully even if the
backend ext4 filesystem has no space to store xattr key-value. That will
cause inconsistent behavior between front end and back end. The reason is
that lsetxattr will be triggered by p9_client_clunk, and unfortunately we
did not catch the error. This patch will catch the error to notify upper
caller.

p9_client_clunk (in 9p)
  p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
    v9fs_clunk (in qemu)
      put_fid
        free_fid
          v9fs_xattr_fid_clunk
            v9fs_co_lsetxattr
              s->ops->lsetxattr
                ext4_xattr_user_set (in host ext4 filesystem)

Link: http://lkml.kernel.org/r/5B57EACC.2060900@huawei.com


Signed-off-by: Jun Piao <piaojun@huawei.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

parent f984579a

fs/9p/xattr.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -105,7 +105,7 @@ int v9fs_fid_xattr_set(struct p9_fid fid, const char name,
		{
		struct kvec kvec = {.iov_base = (void *)value, .iov_len = value_len};
		struct iov_iter from;
		int retval;
		int retval, err;

		iov_iter_kvec(&from, WRITE \| ITER_KVEC, &kvec, 1, value_len);

		@@ -126,7 +126,9 @@ int v9fs_fid_xattr_set(struct p9_fid fid, const char name,
		retval);
		else
		p9_client_write(fid, 0, &from, &retval);
		p9_client_clunk(fid);
		err = p9_client_clunk(fid);
		if (!retval && err)
		retval = err;
		return retval;
		}

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