We must set fl->dsaddr once, and once only, even if there are multiple
processes calling filelayout_check_deviceid() for the same layout
segment.
Reported-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
struct nfs4_file_layout_dsaddr *dsaddr;
int status = -EINVAL;
struct nfs4_file_layout_dsaddr *dsaddr;
int status = -EINVAL;
+ /* Is the deviceid already set? If so, we're good. */
+ if (fl->dsaddr != NULL)
+ return 0;
+
/* find and reference the deviceid */
d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid,
lo->plh_lc_cred, gfp_flags);
/* find and reference the deviceid */
d = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &fl->deviceid,
lo->plh_lc_cred, gfp_flags);
if (filelayout_test_devid_unavailable(&dsaddr->id_node))
goto out_put;
if (filelayout_test_devid_unavailable(&dsaddr->id_node))
goto out_put;
if (fl->first_stripe_index >= dsaddr->stripe_count) {
dprintk("%s Bad first_stripe_index %u\n",
__func__, fl->first_stripe_index);
if (fl->first_stripe_index >= dsaddr->stripe_count) {
dprintk("%s Bad first_stripe_index %u\n",
__func__, fl->first_stripe_index);
goto out_put;
}
status = 0;
goto out_put;
}
status = 0;
+
+ /*
+ * Atomic compare and xchange to ensure we don't scribble
+ * over a non-NULL pointer.
+ */
+ if (cmpxchg(&fl->dsaddr, NULL, dsaddr) != NULL)
+ goto out_put;
out:
return status;
out_put:
out:
return status;
out_put: