fs/9p: Add support for marking inode attribute invalid

With cached mode some of the file system operation result
in updating inode attributes (ctime). Add support for
marking inode attribute invalid in such cases so that
we fetch the updated inode attribute on dentry revalidation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index a4ae4be5ab59..b6a3b9f7fe4d 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -100,7 +100,41 @@ static void v9fs_dentry_release(struct dentry *dentry)
         }
 }
 
+static int v9fs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+        struct p9_fid *fid;
+        struct inode *inode;
+        struct v9fs_inode *v9inode;
+
+        if (nd->flags & LOOKUP_RCU)
+                return -ECHILD;
+
+        inode = dentry->d_inode;
+        if (!inode)
+                goto out_valid;
+
+        v9inode = V9FS_I(inode);
+        if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
+                int retval;
+                struct v9fs_session_info *v9ses;
+                fid = v9fs_fid_lookup(dentry);
+                if (IS_ERR(fid))
+                        return PTR_ERR(fid);
+
+                v9ses = v9fs_inode2v9ses(inode);
+                if (v9fs_proto_dotl(v9ses))
+                        retval = v9fs_refresh_inode_dotl(fid, inode);
+                else
+                        retval = v9fs_refresh_inode(fid, inode);
+                if (retval <= 0)
+                        return retval;
+        }
+out_valid:
+        return 1;
+}
+
 const struct dentry_operations v9fs_cached_dentry_operations = {
+        .d_revalidate = v9fs_lookup_revalidate,
         .d_delete = v9fs_cached_dentry_delete,
         .d_release = v9fs_dentry_release,
 };