NFSv4.1: Clean up the removal of pnfs_layout_hdr from the server list

Move the code into pnfs_free_layout_hdr(), and add checks to
get_layout_by_fh_locked to ensure that they don't reference a layout
that is being freed.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 28 insertions, 20 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 24252fea2c9..76b4a7a3e55 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -122,7 +122,15 @@ static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp,
                         ino = igrab(lo->plh_inode);
                         if (!ino)
                                 continue;
+                        spin_lock(&ino->i_lock);
+                        /* Is this layout in the process of being freed? */
+                        if (NFS_I(ino)->layout != lo) {
+                                spin_unlock(&ino->i_lock);
+                                iput(ino);
+                                continue;
+                        }
                         pnfs_get_layout_hdr(lo);
+                        spin_unlock(&ino->i_lock);
                         return lo;
                 }
         }
@@ -196,9 +204,18 @@ static u32 initiate_bulk_draining(struct nfs_client *clp,
                         continue;
 
                 list_for_each_entry(lo, &server->layouts, plh_layouts) {
-                        if (!igrab(lo->plh_inode))
+                        ino = igrab(lo->plh_inode);
+                        if (ino)
+                                continue;
+                        spin_lock(&ino->i_lock);
+                        /* Is this layout in the process of being freed? */
+                        if (NFS_I(ino)->layout != lo) {
+                                spin_unlock(&ino->i_lock);
+                                iput(ino);
                                 continue;
+                        }
                         pnfs_get_layout_hdr(lo);
+                        spin_unlock(&ino->i_lock);
                         BUG_ON(!list_empty(&lo->plh_bulk_recall));
                         list_add(&lo->plh_bulk_recall, &recall_list);
                 }
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 08663146f5f..11cc0ad6b40 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -207,7 +207,16 @@ pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
 static void
 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
 {
-        struct pnfs_layoutdriver_type *ld = NFS_SERVER(lo->plh_inode)->pnfs_curr_ld;
+        struct nfs_server *server = NFS_SERVER(lo->plh_inode);
+        struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
+
+        if (!list_empty(&lo->plh_layouts)) {
+                struct nfs_client *clp = server->nfs_client;
+
+                spin_lock(&clp->cl_lock);
+                list_del_init(&lo->plh_layouts);
+                spin_unlock(&clp->cl_lock);
+        }
         put_rpccred(lo->plh_lc_cred);
         return ld->alloc_layout_hdr ? ld->free_layout_hdr(lo) : kfree(lo);
 }
@@ -217,7 +226,6 @@ pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
 {
         struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
         dprintk("%s: freeing layout cache %p\n", __func__, lo);
-        BUG_ON(!list_empty(&lo->plh_layouts));
         nfsi->layout = NULL;
         /* Reset MDS Threshold I/O counters */
         nfsi->write_io = 0;
@@ -480,22 +488,10 @@ void
 pnfs_free_lseg_list(struct list_head *free_me)
 {
         struct pnfs_layout_segment *lseg, *tmp;
-        struct pnfs_layout_hdr *lo;
 
         if (list_empty(free_me))
                 return;
 
-        lo = list_first_entry(free_me, struct pnfs_layout_segment,
-                              pls_list)->pls_layout;
-
-        if (test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags)) {
-                struct nfs_client *clp;
-
-                clp = NFS_SERVER(lo->plh_inode)->nfs_client;
-                spin_lock(&clp->cl_lock);
-                list_del_init(&lo->plh_layouts);
-                spin_unlock(&clp->cl_lock);
-        }
         list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
                 list_del(&lseg->pls_list);
                 free_lseg(lseg);
@@ -1148,11 +1144,6 @@ pnfs_update_layout(struct inode *ino,
                 arg.length = PAGE_CACHE_ALIGN(arg.length);
 
         lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
-        if (!lseg && first) {
-                spin_lock(&clp->cl_lock);
-                list_del_init(&lo->plh_layouts);
-                spin_unlock(&clp->cl_lock);
-        }
         atomic_dec(&lo->plh_outstanding);
 out_put_layout_hdr:
         pnfs_put_layout_hdr(lo);