NFSv4.1: Balance pnfs_layout_hdr refcount in pnfs_layout_(insert|remove)_lseg

Ensure that the reference count for pnfs_layout_hdr reverts to the
original value after a call to pnfs_layout_remove_lseg().

Note that the caller is expected to hold a reference to the struct
pnfs_layout_hdr.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index c34ba9a0a46..bdd93b96905 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -320,8 +320,6 @@ static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
         struct inode *ino = lseg->pls_layout->plh_inode;
 
         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
-        /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
-        pnfs_put_layout_hdr(NFS_I(ino)->layout);
 }
 
 static void
@@ -332,6 +330,8 @@ pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
 
         WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
         list_del_init(&lseg->pls_list);
+        /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
+        atomic_dec(&lo->plh_refcount);
         if (list_empty(&lo->plh_segs))
                 set_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags);
         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
@@ -352,9 +352,11 @@ pnfs_put_lseg(struct pnfs_layout_segment *lseg)
         lo = lseg->pls_layout;
         inode = lo->plh_inode;
         if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
+                pnfs_get_layout_hdr(lo);
                 pnfs_layout_remove_lseg(lo, lseg);
                 spin_unlock(&inode->i_lock);
                 pnfs_free_lseg(lseg);
+                pnfs_put_layout_hdr(lo);
         }
 }
 EXPORT_SYMBOL_GPL(pnfs_put_lseg);