diff options
| -rw-r--r-- | fs/namei.c | 123 |
1 files changed, 55 insertions, 68 deletions
diff --git a/fs/namei.c b/fs/namei.c index c9b7f5b7e92..549bbe2f25c 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -785,16 +785,11 @@ __do_follow_link(const struct path *link, struct nameidata *nd, void **p) * Without that kind of total limit, nasty chains of consecutive * symlinks can cause almost arbitrarily long lookups. */ -static inline int do_follow_link(struct inode *inode, struct path *path, struct nameidata *nd) +static inline int do_follow_link(struct path *path, struct nameidata *nd) { void *cookie; int err = -ELOOP; - /* We drop rcu-walk here */ - if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry)) - return -ECHILD; - BUG_ON(inode != path->dentry->d_inode); - if (current->link_count >= MAX_NESTED_LINKS) goto loop; if (current->total_link_count >= 40) @@ -1337,6 +1332,39 @@ static void terminate_walk(struct nameidata *nd) } } +static inline int walk_component(struct nameidata *nd, struct path *path, + struct qstr *name, int type, int follow) +{ + struct inode *inode; + int err; + /* + * "." and ".." are special - ".." especially so because it has + * to be able to know about the current root directory and + * parent relationships. + */ + if (unlikely(type != LAST_NORM)) + return handle_dots(nd, type); + err = do_lookup(nd, name, path, &inode); + if (unlikely(err)) { + terminate_walk(nd); + return err; + } + if (!inode) { + path_to_nameidata(path, nd); + terminate_walk(nd); + return -ENOENT; + } + if (unlikely(inode->i_op->follow_link) && follow) { + if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry)) + return -ECHILD; + BUG_ON(inode != path->dentry->d_inode); + return 1; + } + path_to_nameidata(path, nd); + nd->inode = inode; + return 0; +} + /* * Name resolution. * This is the basic name resolution function, turning a pathname into @@ -1361,7 +1389,6 @@ static int link_path_walk(const char *name, struct nameidata *nd) /* At this point we know we have a real path component. */ for(;;) { - struct inode *inode; unsigned long hash; struct qstr this; unsigned int c; @@ -1414,34 +1441,16 @@ static int link_path_walk(const char *name, struct nameidata *nd) if (!*name) goto last_with_slashes; - /* - * "." and ".." are special - ".." especially so because it has - * to be able to know about the current root directory and - * parent relationships. - */ - if (unlikely(type != LAST_NORM)) { - if (handle_dots(nd, type)) - return -ECHILD; - continue; - } - - /* This does the actual lookups.. */ - err = do_lookup(nd, &this, &next, &inode); - if (err) - break; + err = walk_component(nd, &next, &this, type, LOOKUP_FOLLOW); + if (err < 0) + return err; - if (inode && inode->i_op->follow_link) { - err = do_follow_link(inode, &next, nd); + if (err) { + err = do_follow_link(&next, nd); if (err) return err; nd->inode = nd->path.dentry->d_inode; - } else { - path_to_nameidata(&next, nd); - nd->inode = inode; } - err = -ENOENT; - if (!nd->inode) - break; err = -ENOTDIR; if (!nd->inode->i_op->lookup) break; @@ -1453,36 +1462,27 @@ last_with_slashes: last_component: /* Clear LOOKUP_CONTINUE iff it was previously unset */ nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; - if (lookup_flags & LOOKUP_PARENT) - goto lookup_parent; - if (unlikely(type != LAST_NORM)) - return handle_dots(nd, type); - err = do_lookup(nd, &this, &next, &inode); - if (err) - break; - if (inode && unlikely(inode->i_op->follow_link) && - (lookup_flags & LOOKUP_FOLLOW)) { - err = do_follow_link(inode, &next, nd); + if (lookup_flags & LOOKUP_PARENT) { + nd->last = this; + nd->last_type = type; + return 0; + } + err = walk_component(nd, &next, &this, type, + lookup_flags & LOOKUP_FOLLOW); + if (err < 0) + return err; + if (err) { + err = do_follow_link(&next, nd); if (err) return err; nd->inode = nd->path.dentry->d_inode; - } else { - path_to_nameidata(&next, nd); - nd->inode = inode; } - err = -ENOENT; - if (!nd->inode) - break; if (lookup_flags & LOOKUP_DIRECTORY) { err = -ENOTDIR; if (!nd->inode->i_op->lookup) break; } return 0; -lookup_parent: - nd->last = this; - nd->last_type = type; - return 0; } terminate_walk(nd); return err; @@ -2068,7 +2068,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path, int want_write = 0; int acc_mode = op->acc_mode; struct file *filp; - struct inode *inode; int error; nd->flags &= ~LOOKUP_PARENT; @@ -2111,24 +2110,12 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) symlink_ok = 1; /* we _can_ be in RCU mode here */ - error = do_lookup(nd, &nd->last, path, &inode); - if (error) { - terminate_walk(nd); + error = walk_component(nd, path, &nd->last, LAST_NORM, + !symlink_ok); + if (error < 0) return ERR_PTR(error); - } - if (!inode) { - path_to_nameidata(path, nd); - terminate_walk(nd); - return ERR_PTR(-ENOENT); - } - if (unlikely(inode->i_op->follow_link && !symlink_ok)) { - /* We drop rcu-walk here */ - if (nameidata_dentry_drop_rcu_maybe(nd, path->dentry)) - return ERR_PTR(-ECHILD); + if (error) /* symlink */ return NULL; - } - path_to_nameidata(path, nd); - nd->inode = inode; /* sayonara */ if (nd->flags & LOOKUP_RCU) { if (nameidata_drop_rcu_last(nd)) @@ -2137,7 +2124,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, error = -ENOTDIR; if (nd->flags & LOOKUP_DIRECTORY) { - if (!inode->i_op->lookup) + if (!nd->inode->i_op->lookup) goto exit; } audit_inode(pathname, nd->path.dentry); |