namei: explicitly pass seq number to unlazy_walk() when dentry != NULL

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 756e150..97315df 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -567,13 +567,14 @@ static inline int nd_alloc_stack(struct nameidata *nd)
  * unlazy_walk - try to switch to ref-walk mode.
  * @nd: nameidata pathwalk data
  * @dentry: child of nd->path.dentry or NULL
+ * @seq: seq number to check dentry against
  * Returns: 0 on success, -ECHILD on failure
  *
  * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry
  * for ref-walk mode.  @dentry must be a path found by a do_lookup call on
  * @nd or NULL.  Must be called from rcu-walk context.
  */
-static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
+static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq)
 {
        struct fs_struct *fs = current->fs;
        struct dentry *parent = nd->path.dentry;
@@ -615,7 +616,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
        } else {
                if (!lockref_get_not_dead(&dentry->d_lockref))
                        goto out;
-               if (read_seqcount_retry(&dentry->d_seq, nd->seq))
+               if (read_seqcount_retry(&dentry->d_seq, seq))
                        goto drop_dentry;
        }
 
@@ -671,7 +672,7 @@ static int complete_walk(struct nameidata *nd)
        if (nd->flags & LOOKUP_RCU) {
                if (!(nd->flags & LOOKUP_ROOT))
                        nd->root.mnt = NULL;
-               if (unlikely(unlazy_walk(nd, NULL)))
+               if (unlikely(unlazy_walk(nd, NULL, 0)))
                        return -ECHILD;
        }
 
@@ -1451,7 +1452,7 @@ static int lookup_fast(struct nameidata *nd,
                if (likely(__follow_mount_rcu(nd, path, inode)))
                        return 0;
 unlazy:
-               if (unlazy_walk(nd, dentry))
+               if (unlazy_walk(nd, dentry, nd->seq))
                        return -ECHILD;
        } else {
                dentry = __d_lookup(parent, &nd->last);
@@ -1511,7 +1512,7 @@ static inline int may_lookup(struct nameidata *nd)
                int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
                if (err != -ECHILD)
                        return err;
-               if (unlazy_walk(nd, NULL))
+               if (unlazy_walk(nd, NULL, 0))
                        return -ECHILD;
        }
        return inode_permission(nd->inode, MAY_EXEC);
@@ -1552,7 +1553,7 @@ static int pick_link(struct nameidata *nd, struct path *link)
        }
        if (nd->flags & LOOKUP_RCU) {
                if (unlikely(nd->path.mnt != link->mnt ||
-                            unlazy_walk(nd, link->dentry))) {
+                            unlazy_walk(nd, link->dentry, nd->seq))) {
                        return -ECHILD;
                }
        }
@@ -2297,7 +2298,7 @@ mountpoint_last(struct nameidata *nd, struct path *path)
 
        /* If we're in rcuwalk, drop out of it to handle last component */
        if (nd->flags & LOOKUP_RCU) {
-               if (unlazy_walk(nd, NULL))
+               if (unlazy_walk(nd, NULL, 0))
                        return -ECHILD;
        }