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finally fold get_link() into pick_link()

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kill nd->link_inode, while we are at it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-01-14 14:41:39 -05:00
parent 06708adb99
commit ad6cc4c338
1 changed files with 61 additions and 74 deletions
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135
fs/namei.c
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@ -503,7 +503,6 @@ struct nameidata {
} *stack, internal[EMBEDDED_LEVELS];
struct filename *name;
struct nameidata *saved;
struct inode *link_inode;
unsigned root_seq;
int dfd;
} __randomize_layout;
@ -962,9 +961,8 @@ int sysctl_protected_regular __read_mostly;
*
* Returns 0 if following the symlink is allowed, -ve on error.
*/
static inline int may_follow_link(struct nameidata *nd)
static inline int may_follow_link(struct nameidata *nd, const struct inode *inode)
{
const struct inode *inode;
const struct inode *parent;
kuid_t puid;
@ -972,7 +970,6 @@ static inline int may_follow_link(struct nameidata *nd)
return 0;
/* Allowed if owner and follower match. */
inode = nd->link_inode;
if (uid_eq(current_cred()->fsuid, inode->i_uid))
return 0;
@ -1106,73 +1103,6 @@ static int may_create_in_sticky(umode_t dir_mode, kuid_t dir_uid,
return 0;
}
static __always_inline
const char *get_link(struct nameidata *nd)
{
struct saved *last = nd->stack + nd->depth - 1;
struct dentry *dentry = last->link.dentry;
struct inode *inode = nd->link_inode;
int error;
const char *res;
if (!(nd->flags & LOOKUP_PARENT)) {
error = may_follow_link(nd);
if (unlikely(error))
return ERR_PTR(error);
}
if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS))
return ERR_PTR(-ELOOP);
if (!(nd->flags & LOOKUP_RCU)) {
touch_atime(&last->link);
cond_resched();
} else if (atime_needs_update(&last->link, inode)) {
if (unlikely(unlazy_walk(nd)))
return ERR_PTR(-ECHILD);
touch_atime(&last->link);
}
error = security_inode_follow_link(dentry, inode,
nd->flags & LOOKUP_RCU);
if (unlikely(error))
return ERR_PTR(error);
nd->last_type = LAST_BIND;
res = READ_ONCE(inode->i_link);
if (!res) {
const char * (*get)(struct dentry *, struct inode *,
struct delayed_call *);
get = inode->i_op->get_link;
if (nd->flags & LOOKUP_RCU) {
res = get(NULL, inode, &last->done);
if (res == ERR_PTR(-ECHILD)) {
if (unlikely(unlazy_walk(nd)))
return ERR_PTR(-ECHILD);
res = get(dentry, inode, &last->done);
}
} else {
res = get(dentry, inode, &last->done);
}
if (!res)
goto all_done;
if (IS_ERR(res))
return res;
}
if (*res == '/') {
error = nd_jump_root(nd);
if (unlikely(error))
return ERR_PTR(error);
while (unlikely(*++res == '/'))
;
}
if (*res)
return res;
all_done: // pure jump
put_link(nd);
return NULL;
}
/*
* follow_up - Find the mountpoint of path's vfsmount
*
@ -1796,8 +1726,10 @@ static inline int handle_dots(struct nameidata *nd, int type)
static const char *pick_link(struct nameidata *nd, struct path *link,
struct inode *inode, unsigned seq)
{
int error;
struct saved *last;
const char *res;
int error;
if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {
path_to_nameidata(link, nd);
return ERR_PTR(-ELOOP);
@ -1828,9 +1760,64 @@ static const char *pick_link(struct nameidata *nd, struct path *link,
last = nd->stack + nd->depth++;
last->link = *link;
clear_delayed_call(&last->done);
nd->link_inode = inode;
last->seq = seq;
return get_link(nd);
if (!(nd->flags & LOOKUP_PARENT)) {
error = may_follow_link(nd, inode);
if (unlikely(error))
return ERR_PTR(error);
}
if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS))
return ERR_PTR(-ELOOP);
if (!(nd->flags & LOOKUP_RCU)) {
touch_atime(&last->link);
cond_resched();
} else if (atime_needs_update(&last->link, inode)) {
if (unlikely(unlazy_walk(nd)))
return ERR_PTR(-ECHILD);
touch_atime(&last->link);
}
error = security_inode_follow_link(link->dentry, inode,
nd->flags & LOOKUP_RCU);
if (unlikely(error))
return ERR_PTR(error);
nd->last_type = LAST_BIND;
res = READ_ONCE(inode->i_link);
if (!res) {
const char * (*get)(struct dentry *, struct inode *,
struct delayed_call *);
get = inode->i_op->get_link;
if (nd->flags & LOOKUP_RCU) {
res = get(NULL, inode, &last->done);
if (res == ERR_PTR(-ECHILD)) {
if (unlikely(unlazy_walk(nd)))
return ERR_PTR(-ECHILD);
res = get(link->dentry, inode, &last->done);
}
} else {
res = get(link->dentry, inode, &last->done);
}
if (!res)
goto all_done;
if (IS_ERR(res))
return res;
}
if (*res == '/') {
error = nd_jump_root(nd);
if (unlikely(error))
return ERR_PTR(error);
while (unlikely(*++res == '/'))
;
}
if (*res)
return res;
all_done: // pure jump
put_link(nd);
return NULL;
}
enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};