NFS: Another inode revalidation improvement

If we're trying to update the inode because a previous update left the
cache in a partially unrevalidated state, then allow the update if the
change attrs match.

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

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index d218d16..b88e9dc 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1754,6 +1754,34 @@ static int nfs_inode_attrs_cmp(const struct nfs_fattr *fattr,
        return 0;
 }
 
+/**
+ * nfs_inode_finish_partial_attr_update - complete a previous inode update
+ * @fattr: attributes
+ * @inode: pointer to inode
+ *
+ * Returns '1' if the last attribute update left the inode cached
+ * attributes in a partially unrevalidated state, and @fattr
+ * matches the change attribute of that partial update.
+ * Otherwise returns '0'.
+ */
+static int nfs_inode_finish_partial_attr_update(const struct nfs_fattr *fattr,
+                                               const struct inode *inode)
+{
+       const unsigned long check_valid =
+               NFS_INO_INVALID_ATIME | NFS_INO_INVALID_CTIME |
+               NFS_INO_INVALID_MTIME | NFS_INO_INVALID_SIZE |
+               NFS_INO_INVALID_BLOCKS | NFS_INO_INVALID_OTHER |
+               NFS_INO_INVALID_NLINK;
+       unsigned long cache_validity = NFS_I(inode)->cache_validity;
+
+       if (!(cache_validity & NFS_INO_INVALID_CHANGE) &&
+           (cache_validity & check_valid) != 0 &&
+           (fattr->valid & NFS_ATTR_FATTR_CHANGE) != 0 &&
+           nfs_inode_attrs_cmp_monotonic(fattr, inode) == 0)
+               return 1;
+       return 0;
+}
+
 static int nfs_refresh_inode_locked(struct inode *inode,
                                    struct nfs_fattr *fattr)
 {
@@ -1762,7 +1790,7 @@ static int nfs_refresh_inode_locked(struct inode *inode,
 
        trace_nfs_refresh_inode_enter(inode);
 
-       if (attr_cmp > 0)
+       if (attr_cmp > 0 || nfs_inode_finish_partial_attr_update(fattr, inode))
                ret = nfs_update_inode(inode, fattr);
        else if (attr_cmp == 0)
                ret = nfs_check_inode_attributes(inode, fattr);