ovl: multi-layer readdir
If multiple lower layers exist, merge them as well in readdir according to
the same rules as merging upper with lower. I.e. take whiteouts and opaque
directories into account on all but the lowers layer.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 481e448..dfef6ca 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -261,35 +261,34 @@
static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
{
int err;
- struct path lowerpath;
- struct path upperpath;
+ struct path realpath;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.list = list,
.root = RB_ROOT,
.is_merge = false,
};
+ int idx, next;
- ovl_path_lower(dentry, &lowerpath);
- ovl_path_upper(dentry, &upperpath);
+ for (idx = 0; idx != -1; idx = next) {
+ next = ovl_path_next(idx, dentry, &realpath);
- if (upperpath.dentry) {
- rdd.dir = upperpath.dentry;
- err = ovl_dir_read(&upperpath, &rdd);
- if (err)
- goto out;
+ if (next != -1) {
+ rdd.dir = realpath.dentry;
+ err = ovl_dir_read(&realpath, &rdd);
+ if (err)
+ break;
+ } else {
+ /*
+ * Insert lowest layer entries before upper ones, this
+ * allows offsets to be reasonably constant
+ */
+ list_add(&rdd.middle, rdd.list);
+ rdd.is_merge = true;
+ err = ovl_dir_read(&realpath, &rdd);
+ list_del(&rdd.middle);
+ }
}
- if (lowerpath.dentry) {
- /*
- * Insert lowerpath entries before upperpath ones, this allows
- * offsets to be reasonably constant
- */
- list_add(&rdd.middle, rdd.list);
- rdd.is_merge = true;
- err = ovl_dir_read(&lowerpath, &rdd);
- list_del(&rdd.middle);
- }
-out:
return err;
}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 07e4c57..c245043 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -81,6 +81,9 @@
} else if (!oe->opaque) {
type |= __OVL_PATH_PURE;
}
+ } else {
+ if (oe->numlower > 1)
+ type |= __OVL_PATH_MERGE;
}
return type;
}