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    Subject[PATCH v3 080/110] namei: fold put_link() into the failure case of complete_walk()
    Date
    From: Al Viro <viro@zeniv.linux.org.uk>

    ... and don't open-code unlazy_walk() in there - the only reason
    for that is to avoid verfication of cached nd->root, which is
    trivially avoided by discarding said cached nd->root first.

    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
    ---
    fs/namei.c | 29 ++++++-----------------------
    1 file changed, 6 insertions(+), 23 deletions(-)

    diff --git a/fs/namei.c b/fs/namei.c
    index c6ff9da..55283fe 100644
    --- a/fs/namei.c
    +++ b/fs/namei.c
    @@ -567,6 +567,8 @@ static inline int nd_alloc_stack(struct nameidata *nd)
    * to restart the path walk from the beginning in ref-walk mode.
    */

    +static void terminate_walk(struct nameidata *nd);
    +
    /**
    * unlazy_walk - try to switch to ref-walk mode.
    * @nd: nameidata pathwalk data
    @@ -673,26 +675,12 @@ static int complete_walk(struct nameidata *nd)
    int status;

    if (nd->flags & LOOKUP_RCU) {
    - nd->flags &= ~LOOKUP_RCU;
    if (!(nd->flags & LOOKUP_ROOT))
    nd->root.mnt = NULL;
    -
    - if (!legitimize_mnt(nd->path.mnt, nd->m_seq)) {
    - rcu_read_unlock();
    - return -ECHILD;
    - }
    - if (unlikely(!lockref_get_not_dead(&dentry->d_lockref))) {
    - rcu_read_unlock();
    - mntput(nd->path.mnt);
    - return -ECHILD;
    - }
    - if (read_seqcount_retry(&dentry->d_seq, nd->seq)) {
    - rcu_read_unlock();
    - dput(dentry);
    - mntput(nd->path.mnt);
    + if (unlikely(unlazy_walk(nd, NULL))) {
    + terminate_walk(nd);
    return -ECHILD;
    }
    - rcu_read_unlock();
    }

    if (likely(!(nd->flags & LOOKUP_JUMPED)))
    @@ -708,7 +696,7 @@ static int complete_walk(struct nameidata *nd)
    if (!status)
    status = -ESTALE;

    - path_put(&nd->path);
    + terminate_walk(nd);
    return status;
    }

    @@ -3008,11 +2996,8 @@ static int do_last(struct nameidata *nd,
    * about to look up
    */
    error = complete_walk(nd);
    - if (error) {
    - if (nd->depth)
    - put_link(nd);
    + if (error)
    return error;
    - }

    audit_inode(name, dir, LOOKUP_PARENT);
    error = -EISDIR;
    @@ -3117,8 +3102,6 @@ finish_lookup:
    finish_open:
    error = complete_walk(nd);
    if (error) {
    - if (nd->depth)
    - put_link(nd);
    path_put(&save_parent);
    return error;
    }
    --
    2.1.4


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