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authorAl Viro <viro@zeniv.linux.org.uk>2020-02-28 10:17:52 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2020-04-02 01:09:21 -0400
commit165200d6cb88a3cc1fdeb12e11e97fb96bf685d9 (patch)
tree902a294e9a8e8cc86d7320b434c8411f59fd8e44 /fs/namei.c
parentefe772d6283b3672c0880b10fc4ceea69bc782ca (diff)
downloadlinux-165200d6cb88a3cc1fdeb12e11e97fb96bf685d9.tar.bz2
follow_dotdot(): be lazy about changing nd->path
Change nd->path only after the loop is done and only in case we hadn't ended up finding ourselves in root. Same for NO_XDEV check. That separates the "check how far back do we need to go through the mount stack" logics from the rest of .. traversal. NOTE: path_get/path_put introduced here are temporary. They will go away later in the series. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/fs/namei.c b/fs/namei.c
index af18ede95e2d..9cfb7096e307 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1748,16 +1748,24 @@ static struct dentry *follow_dotdot(struct nameidata *nd,
if (path_equal(&nd->path, &nd->root))
goto in_root;
if (unlikely(nd->path.dentry == nd->path.mnt->mnt_root)) {
+ struct path path = nd->path;
+ path_get(&path);
while (1) {
- if (!follow_up(&nd->path))
+ if (!follow_up(&path)) {
+ path_put(&path);
goto in_root;
- if (unlikely(nd->flags & LOOKUP_NO_XDEV))
- return ERR_PTR(-EXDEV);
- if (path_equal(&nd->path, &nd->root))
+ }
+ if (path_equal(&path, &nd->root)) {
+ path_put(&path);
goto in_root;
- if (nd->path.dentry != nd->path.mnt->mnt_root)
+ }
+ if (path.dentry != nd->path.mnt->mnt_root)
break;
}
+ path_put(&nd->path);
+ nd->path = path;
+ if (unlikely(nd->flags & LOOKUP_NO_XDEV))
+ return ERR_PTR(-EXDEV);
}
/* rare case of legitimate dget_parent()... */
parent = dget_parent(nd->path.dentry);