When non directory upper has overlay.fh xattr, lookup in lower layers
by file handle or by path to find the copy up origin inode.
Until this change a non-dir dentry could have had oe->numlower == 1
with oe->lowerstack[0] pointing at the copy up origin path, right
after copy up, but not when a non-dir dentry was created by ovl_lookup().
After this change, a non-dir dentry could be pointing at the copy up
origin after ovl_lookup(), as long as the copy up was done by overlayfs
that had redirect_fh support.
Non-dir entries that were copied up by overlayfs without redirect_fh
support will look the same as pure upper non-dir entries.
This is going to be used for persistent inode numbers across copy up.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/namei.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 0d1cc8f..318092a 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -225,15 +225,16 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
goto put_and_out;
}
if (!d_can_lookup(this)) {
- d->stop = true;
- if (d->is_dir)
+ if (d->is_dir) {
+ d->stop = true;
goto put_and_out;
- goto out;
- }
- d->is_dir = true;
- if (!d->last && ovl_is_opaquedir(this)) {
- d->stop = d->opaque = true;
- goto out;
+ }
+ } else {
+ d->is_dir = true;
+ if (!d->last && ovl_is_opaquedir(this)) {
+ d->stop = d->opaque = true;
+ goto out;
+ }
}
if (d->last)
goto out;
@@ -247,6 +248,9 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
if (err)
goto out_err;
}
+ /* No redirect for non-dir means pure upper */
+ if (!d->is_dir)
+ d->stop = !d->fh && !d->redirect;
out:
*ret = this;
return 0;
@@ -385,11 +389,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
}
/*
- * For now we only support lower by fh in single layer, because
- * fallback from lookup by fh to lookup by path in mid layers for
- * merge directory is not yet implemented.
+ * For now we only support lookup by fh in single layer for directory,
+ * because fallback from lookup by fh to lookup by path in mid layers
+ * for merge directory is not yet implemented.
*/
- if (!ofs->redirect_fh || ofs->numlower > 1) {
+ if (!ofs->redirect_fh || (d.is_dir && ofs->numlower > 1)) {
kfree(d.fh);
d.fh = NULL;
}
@@ -402,7 +406,6 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
goto out_put_upper;
}
- /* Try to lookup lower layers by file handle */
d.by_path = false;
for (i = 0; !d.stop && d.fh && i < roe->numlower; i++) {
struct path lowerpath = poe->lowerstack[i];
@@ -446,7 +449,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
stack[ctr].mnt = lowerpath.mnt;
ctr++;
- if (d.stop)
+ /* Do not follow non-dir copy up origin more than once */
+ if (d.stop || !d.is_dir)
break;
if (d.redirect && d.redirect[0] == '/' && poe != roe) {
--
2.7.4
