[PATCH v3 047/110] namei: move link/cookie pairs into nameidata

From: Al Viro
Date: Mon May 11 2015 - 14:35:18 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

Array of MAX_NESTED_LINKS + 1 elements put into nameidata;
what used to be a local array in link_path_walk() occupies
entries 1 .. MAX_NESTED_LINKS in it, link and cookie from
the trailing symlink handling loops - entry 0.

This is _not_ the final arrangement; just an easily verified
incremental step.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 35 ++++++++++++++++++-----------------
1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c105107..d4b238a 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -505,6 +505,11 @@ struct nameidata {
int last_type;
unsigned depth;
struct file *base;
+ struct saved {
+ struct path link;
+ void *cookie;
+ const char *name;
+ } stack[MAX_NESTED_LINKS + 1];
};

/*
@@ -1711,11 +1716,7 @@ static inline u64 hash_name(const char *name)
*/
static int link_path_walk(const char *name, struct nameidata *nd)
{
- struct saved {
- struct path link;
- void *cookie;
- const char *name;
- } stack[MAX_NESTED_LINKS], *last = stack + nd->depth - 1;
+ struct saved *last = nd->stack;
int err;

while (*name=='/')
@@ -2030,13 +2031,13 @@ static int path_lookupat(int dfd, const struct filename *name,
if (!err && !(flags & LOOKUP_PARENT)) {
err = lookup_last(nd);
while (err > 0) {
- void *cookie;
- struct path link = nd->link;
- err = trailing_symlink(&link, nd, &cookie);
+ nd->stack[0].link = nd->link;
+ err = trailing_symlink(&nd->stack[0].link,
+ nd, &nd->stack[0].cookie);
if (err)
break;
err = lookup_last(nd);
- put_link(nd, &link, cookie);
+ put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
}
}

@@ -2376,13 +2377,13 @@ path_mountpoint(int dfd, const struct filename *name, struct path *path,

err = mountpoint_last(nd, path);
while (err > 0) {
- void *cookie;
- struct path link = *path;
- err = trailing_symlink(&link, nd, &cookie);
+ nd->stack[0].link = nd->link;
+ err = trailing_symlink(&nd->stack[0].link,
+ nd, &nd->stack[0].cookie);
if (err)
break;
err = mountpoint_last(nd, path);
- put_link(nd, &link, cookie);
+ put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
}
out:
path_cleanup(nd);
@@ -3259,14 +3260,14 @@ static struct file *path_openat(int dfd, struct filename *pathname,

error = do_last(nd, file, op, &opened, pathname);
while (unlikely(error > 0)) { /* trailing symlink */
- struct path link = nd->link;
- void *cookie;
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
- error = trailing_symlink(&link, nd, &cookie);
+ nd->stack[0].link = nd->link;
+ error= trailing_symlink(&nd->stack[0].link,
+ nd, &nd->stack[0].cookie);
if (unlikely(error))
break;
error = do_last(nd, file, op, &opened, pathname);
- put_link(nd, &link, cookie);
+ put_link(nd, &nd->stack[0].link, nd->stack[0].cookie);
}
out:
path_cleanup(nd);
--
2.1.4

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