NFSv4.1: Ensure that we free existing layout segments if we get a new layout

If the server returns a completely new layout stateid in response to our
LAYOUTGET, then make sure to free any existing layout segments.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 6e67ada6c22c..cb53d450ae32 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -665,6 +665,17 @@ static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
         return (s32)(s1 - s2) > 0;
 }
 
+static void
+pnfs_verify_layout_stateid(struct pnfs_layout_hdr *lo,
+                const nfs4_stateid *new,
+                struct list_head *free_me_list)
+{
+        if (nfs4_stateid_match_other(&lo->plh_stateid, new))
+                return;
+        /* Layout is new! Kill existing layout segments */
+        pnfs_mark_matching_lsegs_invalid(lo, free_me_list, NULL);
+}
+
 /* update lo->plh_stateid with new if is more recent */
 void
 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
@@ -1315,6 +1326,7 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         struct nfs4_layoutget_res *res = &lgp->res;
         struct pnfs_layout_segment *lseg;
         struct inode *ino = lo->plh_inode;
+        LIST_HEAD(free_me);
         int status = 0;
 
         /* Inject layout blob into I/O device driver */
@@ -1341,6 +1353,8 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
                 goto out_forget_reply;
         }
 
+        /* Check that the new stateid matches the old stateid */
+        pnfs_verify_layout_stateid(lo, &res->stateid, &free_me);
         /* Done processing layoutget. Set the layout stateid */
         pnfs_set_layout_stateid(lo, &res->stateid, false);
 
@@ -1355,6 +1369,7 @@ pnfs_layout_process(struct nfs4_layoutget *lgp)
         }
 
         spin_unlock(&ino->i_lock);
+        pnfs_free_lseg_list(&free_me);
         return lseg;
 out:
         return ERR_PTR(status);