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namei: fold should_follow_link() with the step into not-followed link

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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 <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-11-14 01:50:26 -05:00
parent 31d66bcd3f
commit 8f64fb1cce
1 changed files with 18 additions and 30 deletions
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48
fs/namei.c
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@ -1725,7 +1725,7 @@ static int pick_link(struct nameidata *nd, struct path *link,
return 1; 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 * 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" * so we keep a cache of "no, this doesn't need follow_link"
* for the common case. * for the common case.
*/ */
static inline int should_follow_link(struct nameidata *nd, struct path *link, static inline int step_into(struct nameidata *nd, struct path *path,
int flags, int flags, struct inode *inode, unsigned seq)
struct inode *inode, unsigned seq)
{ {
if (!(flags & WALK_MORE) && nd->depth) if (!(flags & WALK_MORE) && nd->depth)
put_link(nd); put_link(nd);
if (likely(!d_is_symlink(link->dentry))) if (likely(!d_is_symlink(path->dentry)) ||
return 0; !(flags & WALK_FOLLOW || nd->flags & LOOKUP_FOLLOW)) {
if (!(flags & WALK_GET) && !(nd->flags & LOOKUP_FOLLOW)) /* not a symlink or should not follow */
path_to_nameidata(path, nd);
nd->inode = inode;
nd->seq = seq;
return 0; return 0;
}
/* make sure that d_is_symlink above matches inode */ /* make sure that d_is_symlink above matches inode */
if (nd->flags & LOOKUP_RCU) { 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 -ECHILD;
} }
return pick_link(nd, link, inode, seq); return pick_link(nd, path, inode, seq);
} }
static int walk_component(struct nameidata *nd, int flags) 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); inode = d_backing_inode(path.dentry);
} }
err = should_follow_link(nd, &path, flags, inode, seq); return step_into(nd, &path, flags, inode, seq);
if (unlikely(err))
return err;
path_to_nameidata(&path, nd);
nd->inode = inode;
nd->seq = seq;
return 0;
} }
/* /*
@ -2104,10 +2101,10 @@ OK:
if (!name) if (!name)
return 0; return 0;
/* last component of nested symlink */ /* last component of nested symlink */
err = walk_component(nd, WALK_GET); err = walk_component(nd, WALK_FOLLOW);
} else { } else {
/* not the last component */ /* not the last component */
err = walk_component(nd, WALK_GET | WALK_MORE); err = walk_component(nd, WALK_FOLLOW | WALK_MORE);
} }
if (err < 0) if (err < 0)
return err; return err;
@ -2617,12 +2614,7 @@ mountpoint_last(struct nameidata *nd)
return -ENOENT; return -ENOENT;
} }
path.mnt = nd->path.mnt; path.mnt = nd->path.mnt;
error = should_follow_link(nd, &path, 0, return step_into(nd, &path, 0, d_backing_inode(path.dentry), 0);
d_backing_inode(path.dentry), 0);
if (unlikely(error))
return error;
path_to_nameidata(&path, nd);
return 0;
} }
/** /**
@ -3311,15 +3303,11 @@ static int do_last(struct nameidata *nd,
seq = 0; /* out of RCU mode, so the value doesn't matter */ seq = 0; /* out of RCU mode, so the value doesn't matter */
inode = d_backing_inode(path.dentry); inode = d_backing_inode(path.dentry);
finish_lookup: finish_lookup:
error = should_follow_link(nd, &path, 0, inode, seq); error = step_into(nd, &path, 0, inode, seq);
if (unlikely(error)) if (unlikely(error))
return 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: finish_open:
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
error = complete_walk(nd); error = complete_walk(nd);
if (error) if (error)
return error; return error;