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authorAmir Goldstein <amir73il@gmail.com>2017-06-21 15:28:34 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2017-07-04 23:03:17 +0300
commitf7d3daca7c79d9b77e61f50f718b257b71d07498 (patch)
tree30087498874a86d2ceda3c2cfd41e463e611345f /fs/overlayfs
parent2cac0c00a6cdcc9121de150ed531f652396d1544 (diff)
downloadlinux-f7d3daca7c79d9b77e61f50f718b257b71d07498.tar.xz
ovl: relax same fs constrain for ovl_check_origin()
For the case of all layers not on the same fs, try to decode the copy up origin file handle on any of the lower layers. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/namei.c42
1 files changed, 24 insertions, 18 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 277a55c8299a..6485beddaa1f 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -272,28 +272,24 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
static int ovl_check_origin(struct dentry *dentry, struct dentry *upperdentry,
struct path **stackp, unsigned int *ctrp)
{
- struct super_block *same_sb = ovl_same_sb(dentry->d_sb);
struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata;
struct vfsmount *mnt;
- struct dentry *origin;
+ struct dentry *origin = NULL;
+ int i;
- if (!same_sb || !roe->numlower)
- return 0;
- /*
- * Since all layers are on the same fs, we use the first layer for
- * decoding the file handle. We may get a disconnected dentry,
- * which is fine, because we only need to hold the origin inode in
- * cache and use its inode number. We may even get a connected dentry,
- * that is not under the first layer's root. That is also fine for
- * using it's inode number - it's the same as if we held a reference
- * to a dentry in first layer that was moved under us.
- */
- mnt = roe->lowerstack[0].mnt;
-
- origin = ovl_get_origin(upperdentry, mnt);
- if (IS_ERR_OR_NULL(origin))
- return PTR_ERR(origin);
+ for (i = 0; i < roe->numlower; i++) {
+ mnt = roe->lowerstack[i].mnt;
+ origin = ovl_get_origin(upperdentry, mnt);
+ if (IS_ERR(origin))
+ return PTR_ERR(origin);
+
+ if (origin)
+ break;
+ }
+
+ if (!origin)
+ return 0;
BUG_ON(*stackp || *ctrp);
*stackp = kmalloc(sizeof(struct path), GFP_TEMPORARY);
@@ -371,6 +367,16 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
}
if (upperdentry && !d.is_dir) {
BUG_ON(!d.stop || d.redirect);
+ /*
+ * Lookup copy up origin by decoding origin file handle.
+ * We may get a disconnected dentry, which is fine,
+ * because we only need to hold the origin inode in
+ * cache and use its inode number. We may even get a
+ * connected dentry, that is not under any of the lower
+ * layers root. That is also fine for using it's inode
+ * number - it's the same as if we held a reference
+ * to a dentry in lower layer that was moved under us.
+ */
err = ovl_check_origin(dentry, upperdentry,
&stack, &ctr);
if (err)