From 8f64fb1ccef331077a96cbfc3c23f91cbe563fd0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 14 Nov 2016 01:50:26 -0500 Subject: [PATCH] namei: fold should_follow_link() with the step into not-followed link All callers are followed by the same boilerplate - "if it has returned 0, update nd->path/inode/seq - we are not following a symlink here". Pull it into the function itself, renaming it into step_into(). Rename WALK_GET to WALK_FOLLOW, while we are at it - more descriptive name. Signed-off-by: Al Viro --- fs/namei.c | 48 ++++++++++++++++++------------------------------ 1 file changed, 18 insertions(+), 30 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 5d31f0b2006d..092ac5667ec7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1725,7 +1725,7 @@ static int pick_link(struct nameidata *nd, struct path *link, return 1; } -enum {WALK_GET = 1, WALK_MORE = 2}; +enum {WALK_FOLLOW = 1, WALK_MORE = 2}; /* * Do we need to follow links? We _really_ want to be able @@ -1733,22 +1733,25 @@ enum {WALK_GET = 1, WALK_MORE = 2}; * so we keep a cache of "no, this doesn't need follow_link" * for the common case. */ -static inline int should_follow_link(struct nameidata *nd, struct path *link, - int flags, - struct inode *inode, unsigned seq) +static inline int step_into(struct nameidata *nd, struct path *path, + int flags, struct inode *inode, unsigned seq) { if (!(flags & WALK_MORE) && nd->depth) put_link(nd); - if (likely(!d_is_symlink(link->dentry))) - return 0; - if (!(flags & WALK_GET) && !(nd->flags & LOOKUP_FOLLOW)) + if (likely(!d_is_symlink(path->dentry)) || + !(flags & WALK_FOLLOW || nd->flags & LOOKUP_FOLLOW)) { + /* not a symlink or should not follow */ + path_to_nameidata(path, nd); + nd->inode = inode; + nd->seq = seq; return 0; + } /* make sure that d_is_symlink above matches inode */ if (nd->flags & LOOKUP_RCU) { - if (read_seqcount_retry(&link->dentry->d_seq, seq)) + if (read_seqcount_retry(&path->dentry->d_seq, seq)) return -ECHILD; } - return pick_link(nd, link, inode, seq); + return pick_link(nd, path, inode, seq); } static int walk_component(struct nameidata *nd, int flags) @@ -1791,13 +1794,7 @@ static int walk_component(struct nameidata *nd, int flags) inode = d_backing_inode(path.dentry); } - err = should_follow_link(nd, &path, flags, inode, seq); - if (unlikely(err)) - return err; - path_to_nameidata(&path, nd); - nd->inode = inode; - nd->seq = seq; - return 0; + return step_into(nd, &path, flags, inode, seq); } /* @@ -2104,10 +2101,10 @@ OK: if (!name) return 0; /* last component of nested symlink */ - err = walk_component(nd, WALK_GET); + err = walk_component(nd, WALK_FOLLOW); } else { /* not the last component */ - err = walk_component(nd, WALK_GET | WALK_MORE); + err = walk_component(nd, WALK_FOLLOW | WALK_MORE); } if (err < 0) return err; @@ -2617,12 +2614,7 @@ mountpoint_last(struct nameidata *nd) return -ENOENT; } path.mnt = nd->path.mnt; - error = should_follow_link(nd, &path, 0, - d_backing_inode(path.dentry), 0); - if (unlikely(error)) - return error; - path_to_nameidata(&path, nd); - return 0; + return step_into(nd, &path, 0, d_backing_inode(path.dentry), 0); } /** @@ -3311,15 +3303,11 @@ static int do_last(struct nameidata *nd, seq = 0; /* out of RCU mode, so the value doesn't matter */ inode = d_backing_inode(path.dentry); finish_lookup: - error = should_follow_link(nd, &path, 0, inode, seq); + error = step_into(nd, &path, 0, inode, seq); if (unlikely(error)) return error; - - path_to_nameidata(&path, nd); - nd->inode = inode; - nd->seq = seq; - /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ finish_open: + /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ error = complete_walk(nd); if (error) return error; -- 2.20.1