NFS: Add attribute update barriers to nfs_setattr_update_inode()

[cascardo/linux.git] / fs / nfs / inode.c

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e4f0dce..3a2d127 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -556,6 +556,7 @@ EXPORT_SYMBOL_GPL(nfs_setattr);
  * This is a copy of the common vmtruncate, but with the locking
  * corrected to take into account the fact that NFS requires
  * inode->i_size to be updated under the inode->i_lock.
+ * Note: must be called with inode->i_lock held!
  */
 static int nfs_vmtruncate(struct inode * inode, loff_t offset)
 {
@@ -565,14 +566,14 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset)
        if (err)
                goto out;
 
-       spin_lock(&inode->i_lock);
        i_size_write(inode, offset);
        /* Optimisation */
        if (offset == 0)
                NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_DATA;
-       spin_unlock(&inode->i_lock);
 
+       spin_unlock(&inode->i_lock);
        truncate_pagecache(inode, offset);
+       spin_lock(&inode->i_lock);
 out:
        return err;
 }
@@ -585,10 +586,15 @@ out:
  * Note: we do this in the *proc.c in order to ensure that
  *       it works for things like exclusive creates too.
  */
-void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
+void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr,
+               struct nfs_fattr *fattr)
 {
+       /* Barrier: bump the attribute generation count. */
+       nfs_fattr_set_barrier(fattr);
+
+       spin_lock(&inode->i_lock);
+       NFS_I(inode)->attr_gencount = fattr->gencount;
        if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
-               spin_lock(&inode->i_lock);
                if ((attr->ia_valid & ATTR_MODE) != 0) {
                        int mode = attr->ia_mode & S_IALLUGO;
                        mode |= inode->i_mode & ~S_IALLUGO;
@@ -600,12 +606,13 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
                        inode->i_gid = attr->ia_gid;
                nfs_set_cache_invalid(inode, NFS_INO_INVALID_ACCESS
                                | NFS_INO_INVALID_ACL);
-               spin_unlock(&inode->i_lock);
        }
        if ((attr->ia_valid & ATTR_SIZE) != 0) {
                nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC);
                nfs_vmtruncate(inode, attr->ia_size);
        }
+       nfs_update_inode(inode, fattr);
+       spin_unlock(&inode->i_lock);
 }
 EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);
 
@@ -1260,6 +1267,22 @@ void nfs_fattr_init(struct nfs_fattr *fattr)
 }
 EXPORT_SYMBOL_GPL(nfs_fattr_init);
 
+/**
+ * nfs_fattr_set_barrier
+ * @fattr: attributes
+ *
+ * Used to set a barrier after an attribute was updated. This
+ * barrier ensures that older attributes from RPC calls that may
+ * have raced with our update cannot clobber these new values.
+ * Note that you are still responsible for ensuring that other
+ * operations which change the attribute on the server do not
+ * collide.
+ */
+void nfs_fattr_set_barrier(struct nfs_fattr *fattr)
+{
+       fattr->gencount = nfs_inc_attr_generation_counter();
+}
+
 struct nfs_fattr *nfs_alloc_fattr(void)
 {
        struct nfs_fattr *fattr;
@@ -1775,7 +1798,6 @@ static inline void nfs4_init_once(struct nfs_inode *nfsi)
 #if IS_ENABLED(CONFIG_NFS_V4)
        INIT_LIST_HEAD(&nfsi->open_states);
        nfsi->delegation = NULL;
-       nfsi->delegation_state = 0;
        init_rwsem(&nfsi->rwsem);
        nfsi->layout = NULL;
 #endif