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

piaojun
2018-07-25T03:13:41Z

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)

Signed-off-by: Jun Piao <piaojun@huawei.com>
---
fs/9p/xattr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index f329eee..352abc3 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -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;
}

--