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pick_link(): take reserving space on stack into a new helper 

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-03-03 11:22:34 -05:00
parent aef9404d8c
commit 49055906af
1 changed files with 25 additions and 21 deletions
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46
fs/namei.c
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@ -1580,6 +1580,28 @@ static inline int may_lookup(struct nameidata *nd)
return inode_permission(nd->inode, MAY_EXEC);
}
static int reserve_stack(struct nameidata *nd, struct path *link, unsigned seq)
{
int error;
if (unlikely(nd->total_link_count++ >= MAXSYMLINKS))
return -ELOOP;
error = nd_alloc_stack(nd);
if (likely(!error))
return 0;
if (error == -ECHILD) {
// we must grab link first
bool grabbed_link = legitimize_path(nd, link, seq);
// ... and we must unlazy to be able to clean up
error = unlazy_walk(nd);
if (unlikely(!grabbed_link))
error = -ECHILD;
if (!error)
error = nd_alloc_stack(nd);
}
return error;
}
enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};
static const char *pick_link(struct nameidata *nd, struct path *link,
@ -1587,31 +1609,13 @@ static const char *pick_link(struct nameidata *nd, struct path *link,
{
struct saved *last;
const char *res;
int error;
int error = reserve_stack(nd, link, seq);
if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {
if (unlikely(error)) {
if (!(nd->flags & LOOKUP_RCU))
path_put(link);
return ERR_PTR(-ELOOP);
return ERR_PTR(error);
}
error = nd_alloc_stack(nd);
if (unlikely(error)) {
if (error == -ECHILD) {
// we must grab link first
bool grabbed_link = legitimize_path(nd, link, seq);
// ... and we must unlazy to be able to clean up
error = unlazy_walk(nd);
if (unlikely(!grabbed_link))
error = -ECHILD;
if (!error)
error = nd_alloc_stack(nd);
}
if (error) {
path_put(link);
return ERR_PTR(error);
}
}
last = nd->stack + nd->depth++;
last->link = *link;
clear_delayed_call(&last->done);