ovl: create ovl_need_index() helper

The helper determines which lower file needs to be indexed
on copy up and before nlink changes.

For index=on, the helper evaluates to true for lower hardlinks.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 503c924..103e62d 100644 (file)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -536,11 +536,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
 {
        int err;
        struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info;
-       bool indexed = false;
-
-       if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) &&
-           c->stat.nlink > 1)
-               indexed = true;
+       bool indexed = ovl_need_index(c->dentry);
 
        if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed)
                c->origin = true;

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 25794a3..d7e6528 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -241,6 +241,7 @@ void ovl_clear_flag(unsigned long flag, struct inode *inode);
 bool ovl_test_flag(unsigned long flag, struct inode *inode);
 bool ovl_inuse_trylock(struct dentry *dentry);
 void ovl_inuse_unlock(struct dentry *dentry);
+bool ovl_need_index(struct dentry *dentry);
 int ovl_nlink_start(struct dentry *dentry, bool *locked);
 void ovl_nlink_end(struct dentry *dentry, bool locked);
 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index ae81d87..55ab991 100644 (file)
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -463,6 +463,23 @@ void ovl_inuse_unlock(struct dentry *dentry)
        }
 }
 
+/*
+ * Does this overlay dentry need to be indexed on copy up?
+ */
+bool ovl_need_index(struct dentry *dentry)
+{
+       struct dentry *lower = ovl_dentry_lower(dentry);
+
+       if (!lower || !ovl_indexdir(dentry->d_sb))
+               return false;
+
+       /* Index only lower hardlinks on copy up */
+       if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
+               return true;
+
+       return false;
+}
+
 /* Caller must hold OVL_I(inode)->lock */
 static void ovl_cleanup_index(struct dentry *dentry)
 {
@@ -533,11 +550,11 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked)
 
        /*
         * With inodes index is enabled, we store the union overlay nlink
-        * in an xattr on the index inode. When whiting out lower hardlinks
+        * in an xattr on the index inode. When whiting out an indexed lower,
         * we need to decrement the overlay persistent nlink, but before the
         * first copy up, we have no upper index inode to store the xattr.
         *
-        * As a workaround, before whiteout/rename over of a lower hardlink,
+        * As a workaround, before whiteout/rename over an indexed lower,
         * copy up to create the upper index. Creating the upper index will
         * initialize the overlay nlink, so it could be dropped if unlink
         * or rename succeeds.
@@ -545,8 +562,7 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked)
         * TODO: implement metadata only index copy up when called with
         *       ovl_copy_up_flags(dentry, O_PATH).
         */
-       if (ovl_indexdir(dentry->d_sb) && !ovl_dentry_has_upper_alias(dentry) &&
-           d_inode(ovl_dentry_lower(dentry))->i_nlink > 1) {
+       if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) {
                err = ovl_copy_up(dentry);
                if (err)
                        return err;