diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2015-05-03 20:01:27 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-05-10 22:20:02 -0400 |
| commit | 071bf501379560a7631b8d75ac80165bf82735c4 (patch) | |
| tree | e85e69c4f98b12fc7d5a619c34ec62278bad3879 /fs/namei.c | |
| parent | 894bc8c4662ba9daceafe943a5ba0dd407da5cd3 (diff) | |
| download | lwn-071bf501379560a7631b8d75ac80165bf82735c4.tar.gz lwn-071bf501379560a7631b8d75ac80165bf82735c4.zip | |
link_path_walk: nd->depth massage, part 1
nd->stack[0] is unused until the handling of trailing symlinks and
we want to get rid of that. Having fucked that transformation up
several times, I went for bloody pedantic series of provably equivalent
transformations. Sorry.
Step 1: keep nd->depth higher by one in link_path_walk() - increment upon
entry, decrement on exits, adjust the arithmetics inside and surround the
calls of functions that care about nd->depth value (nd_alloc_stack(),
get_link(), put_link()) with decrement/increment pairs.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/fs/namei.c b/fs/namei.c index 1ae34cd0d590..e408f4d0c85f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1763,6 +1763,7 @@ static int link_path_walk(const char *name, struct nameidata *nd) if (!*name) return 0; + nd->depth++; /* At this point we know we have a real path component. */ for(;;) { u64 hash_len; @@ -1823,15 +1824,18 @@ Walked: if (err) { const char *s; + nd->depth--; err = nd_alloc_stack(nd); + nd->depth++; if (unlikely(err)) { path_to_nameidata(&nd->link, nd); break; } nd->depth++; - + nd->depth--; s = get_link(nd); + nd->depth++; if (unlikely(IS_ERR(s))) { err = PTR_ERR(s); @@ -1841,7 +1845,9 @@ Walked: err = 0; if (unlikely(!s)) { /* jumped */ + nd->depth--; put_link(nd); + nd->depth++; nd->depth--; } else { if (*s == '/') { @@ -1855,7 +1861,7 @@ Walked: ; } nd->inode = nd->path.dentry->d_inode; - nd->stack[nd->depth].name = name; + nd->stack[nd->depth - 1].name = name; if (!*s) goto OK; name = s; @@ -1869,19 +1875,25 @@ Walked: } terminate_walk(nd); Err: - while (unlikely(nd->depth)) { + while (unlikely(nd->depth > 1)) { + nd->depth--; put_link(nd); + nd->depth++; nd->depth--; } + nd->depth--; return err; OK: - if (unlikely(nd->depth)) { - name = nd->stack[nd->depth].name; + if (unlikely(nd->depth > 1)) { + name = nd->stack[nd->depth - 1].name; err = walk_component(nd, LOOKUP_FOLLOW); + nd->depth--; put_link(nd); + nd->depth++; nd->depth--; goto Walked; } + nd->depth--; return 0; } |