}
EXPORT_SYMBOL(path_put);
+#define EMBEDDED_LEVELS 2
struct nameidata {
struct path path;
struct qstr last;
unsigned seq, m_seq;
int last_type;
unsigned depth;
- struct file *base;
- char *saved_names[MAX_NESTED_LINKS + 1];
+ int total_link_count;
+ struct saved {
+ struct path link;
+ void *cookie;
+ const char *name;
+ struct inode *inode;
+ unsigned seq;
+ } *stack, internal[EMBEDDED_LEVELS];
+ struct filename *name;
+ struct nameidata *saved;
+ unsigned root_seq;
+ int dfd;
};
+static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
+{
+ struct nameidata *old = current->nameidata;
+ p->stack = p->internal;
+ p->dfd = dfd;
+ p->name = name;
+ p->total_link_count = old ? old->total_link_count : 0;
+ p->saved = old;
+ current->nameidata = p;
+}
+
+static void restore_nameidata(void)
+{
+ struct nameidata *now = current->nameidata, *old = now->saved;
+
+ current->nameidata = old;
+ if (old)
+ old->total_link_count = now->total_link_count;
+ if (now->stack != now->internal) {
+ kfree(now->stack);
+ now->stack = now->internal;
+ }
+}
+
+static int __nd_alloc_stack(struct nameidata *nd)
+{
+ struct saved *p;
+
+ if (nd->flags & LOOKUP_RCU) {
+ p= kmalloc(MAXSYMLINKS * sizeof(struct saved),
+ GFP_ATOMIC);
+ if (unlikely(!p))
+ return -ECHILD;
+ } else {
+ p= kmalloc(MAXSYMLINKS * sizeof(struct saved),
+ GFP_KERNEL);
+ if (unlikely(!p))
+ return -ENOMEM;
+ }
+ memcpy(p, nd->internal, sizeof(nd->internal));
+ nd->stack = p;
+ return 0;
+}
+
+/**
+ * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
+ * @path: nameidate to verify
+ *
+ * Rename can sometimes move a file or directory outside of a bind
+ * mount, path_connected allows those cases to be detected.
+ */
+static bool path_connected(const struct path *path)
+{
+ struct vfsmount *mnt = path->mnt;
+
+ /* Only bind mounts can have disconnected paths */
+ if (mnt->mnt_root == mnt->mnt_sb->s_root)
+ return true;
+
+ return is_subdir(path->dentry, mnt->mnt_root);
+}
+
+static inline int nd_alloc_stack(struct nameidata *nd)
+{
+ if (likely(nd->depth != EMBEDDED_LEVELS))
+ return 0;
+ if (likely(nd->stack != nd->internal))
+ return 0;
+ return __nd_alloc_stack(nd);
+}
+
+static void drop_links(struct nameidata *nd)
+{
+ int i = nd->depth;
+ while (i--) {
+ struct saved *last = nd->stack + i;
+ struct inode *inode = last->inode;
+ if (last->cookie && inode->i_op->put_link) {
+ inode->i_op->put_link(inode, last->cookie);
+ last->cookie = NULL;
+ }
+ }
+}
+
+static void terminate_walk(struct nameidata *nd)
+{
+ drop_links(nd);
+ if (!(nd->flags & LOOKUP_RCU)) {
+ int i;
+ path_put(&nd->path);
+ for (i = 0; i < nd->depth; i++)
+ path_put(&nd->stack[i].link);
+ if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+ path_put(&nd->root);
+ nd->root.mnt = NULL;
+ }
+ } else {
+ nd->flags &= ~LOOKUP_RCU;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ }
+ nd->depth = 0;
+}
+
+/* path_put is needed afterwards regardless of success or failure */
+static bool legitimize_path(struct nameidata *nd,
+ struct path *path, unsigned seq)
+{
+ int res = __legitimize_mnt(path->mnt, nd->m_seq);
+ if (unlikely(res)) {
+ if (res > 0)
+ path->mnt = NULL;
+ path->dentry = NULL;
+ return false;
+ }
+ if (unlikely(!lockref_get_not_dead(&path->dentry->d_lockref))) {
+ path->dentry = NULL;
+ return false;
+ }
+ return !read_seqcount_retry(&path->dentry->d_seq, seq);
+}
+
+static bool legitimize_links(struct nameidata *nd)
+{
+ int i;
+ for (i = 0; i < nd->depth; i++) {
+ struct saved *last = nd->stack + i;
+ if (unlikely(!legitimize_path(nd, &last->link, last->seq))) {
+ drop_links(nd);
+ nd->depth = i + 1;
+ return false;
+ }
+ }
+ return true;
+}
+
/*
* Path walking has 2 modes, rcu-walk and ref-walk (see
* Documentation/filesystems/path-lookup.txt). In situations when we can't
* unlazy_walk - try to switch to ref-walk mode.
* @nd: nameidata pathwalk data
* @dentry: child of nd->path.dentry or NULL
+ * @seq: seq number to check dentry against
* Returns: 0 on success, -ECHILD on failure
*
* unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry
* for ref-walk mode. @dentry must be a path found by a do_lookup call on
* @nd or NULL. Must be called from rcu-walk context.
+ * Nothing should touch nameidata between unlazy_walk() failure and
+ * terminate_walk().
*/
-static int unlazy_walk(struct nameidata *nd, struct dentry *dentry)
+static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq)
{
- struct fs_struct *fs = current->fs;
struct dentry *parent = nd->path.dentry;
BUG_ON(!(nd->flags & LOOKUP_RCU));
- /*
- * After legitimizing the bastards, terminate_walk()
- * will do the right thing for non-RCU mode, and all our
- * subsequent exit cases should rcu_read_unlock()
- * before returning. Do vfsmount first; if dentry
- * can't be legitimized, just set nd->path.dentry to NULL
- * and rely on dput(NULL) being a no-op.
- */
- if (!legitimize_mnt(nd->path.mnt, nd->m_seq))
- return -ECHILD;
nd->flags &= ~LOOKUP_RCU;
-
- if (!lockref_get_not_dead(&parent->d_lockref)) {
- nd->path.dentry = NULL;
- goto out;
- }
+ if (unlikely(!legitimize_links(nd)))
+ goto out2;
+ if (unlikely(!legitimize_mnt(nd->path.mnt, nd->m_seq)))
+ goto out2;
+ if (unlikely(!lockref_get_not_dead(&parent->d_lockref)))
+ goto out1;
/*
* For a negative lookup, the lookup sequence point is the parents
} else {
if (!lockref_get_not_dead(&dentry->d_lockref))
goto out;
- if (read_seqcount_retry(&dentry->d_seq, nd->seq))
+ if (read_seqcount_retry(&dentry->d_seq, seq))
goto drop_dentry;
}
* still valid and get it if required.
*/
if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
- spin_lock(&fs->lock);
- if (nd->root.mnt != fs->root.mnt || nd->root.dentry != fs->root.dentry)
- goto unlock_and_drop_dentry;
- path_get(&nd->root);
- spin_unlock(&fs->lock);
+ if (unlikely(!legitimize_path(nd, &nd->root, nd->root_seq))) {
+ rcu_read_unlock();
+ dput(dentry);
+ return -ECHILD;
+ }
}
rcu_read_unlock();
return 0;
-unlock_and_drop_dentry:
- spin_unlock(&fs->lock);
drop_dentry:
rcu_read_unlock();
dput(dentry);
goto drop_root_mnt;
+out2:
+ nd->path.mnt = NULL;
+out1:
+ nd->path.dentry = NULL;
out:
rcu_read_unlock();
drop_root_mnt:
return -ECHILD;
}
+static int unlazy_link(struct nameidata *nd, struct path *link, unsigned seq)
+{
+ if (unlikely(!legitimize_path(nd, link, seq))) {
+ drop_links(nd);
+ nd->depth = 0;
+ nd->flags &= ~LOOKUP_RCU;
+ nd->path.mnt = NULL;
+ nd->path.dentry = NULL;
+ if (!(nd->flags & LOOKUP_ROOT))
+ nd->root.mnt = NULL;
+ rcu_read_unlock();
+ } else if (likely(unlazy_walk(nd, NULL, 0)) == 0) {
+ return 0;
+ }
+ path_put(link);
+ return -ECHILD;
+}
+
static inline int d_revalidate(struct dentry *dentry, unsigned int flags)
{
return dentry->d_op->d_revalidate(dentry, flags);
int status;
if (nd->flags & LOOKUP_RCU) {
- nd->flags &= ~LOOKUP_RCU;
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
-
- if (!legitimize_mnt(nd->path.mnt, nd->m_seq)) {
- rcu_read_unlock();
+ if (unlikely(unlazy_walk(nd, NULL, 0)))
return -ECHILD;
- }
- if (unlikely(!lockref_get_not_dead(&dentry->d_lockref))) {
- rcu_read_unlock();
- mntput(nd->path.mnt);
- return -ECHILD;
- }
- if (read_seqcount_retry(&dentry->d_seq, nd->seq)) {
- rcu_read_unlock();
- dput(dentry);
- mntput(nd->path.mnt);
- return -ECHILD;
- }
- rcu_read_unlock();
}
if (likely(!(nd->flags & LOOKUP_JUMPED)))
if (!status)
status = -ESTALE;
- path_put(&nd->path);
return status;
}
-static __always_inline void set_root(struct nameidata *nd)
+static void set_root(struct nameidata *nd)
{
get_fs_root(current->fs, &nd->root);
}
-static int link_path_walk(const char *, struct nameidata *);
-
-static __always_inline unsigned set_root_rcu(struct nameidata *nd)
+static void set_root_rcu(struct nameidata *nd)
{
struct fs_struct *fs = current->fs;
- unsigned seq, res;
+ unsigned seq;
do {
seq = read_seqcount_begin(&fs->seq);
nd->root = fs->root;
- res = __read_seqcount_begin(&nd->root.dentry->d_seq);
+ nd->root_seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
} while (read_seqcount_retry(&fs->seq, seq));
- return res;
}
static void path_put_conditional(struct path *path, struct nameidata *nd)
* Helper to directly jump to a known parsed path from ->follow_link,
* caller must have taken a reference to path beforehand.
*/
-void nd_jump_link(struct nameidata *nd, struct path *path)
+void nd_jump_link(struct path *path)
{
+ struct nameidata *nd = current->nameidata;
path_put(&nd->path);
nd->path = *path;
nd->flags |= LOOKUP_JUMPED;
}
-void nd_set_link(struct nameidata *nd, char *path)
+static inline void put_link(struct nameidata *nd)
{
- nd->saved_names[nd->depth] = path;
-}
-EXPORT_SYMBOL(nd_set_link);
-
-char *nd_get_link(struct nameidata *nd)
-{
- return nd->saved_names[nd->depth];
-}
-EXPORT_SYMBOL(nd_get_link);
-
-static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
-{
- struct inode *inode = link->dentry->d_inode;
- if (inode->i_op->put_link)
- inode->i_op->put_link(link->dentry, nd, cookie);
- path_put(link);
+ struct saved *last = nd->stack + --nd->depth;
+ struct inode *inode = last->inode;
+ if (last->cookie && inode->i_op->put_link)
+ inode->i_op->put_link(inode, last->cookie);
+ if (!(nd->flags & LOOKUP_RCU))
+ path_put(&last->link);
}
int sysctl_protected_symlinks __read_mostly = 0;
/**
* may_follow_link - Check symlink following for unsafe situations
- * @link: The path of the symlink
* @nd: nameidata pathwalk data
*
* In the case of the sysctl_protected_symlinks sysctl being enabled,
*
* Returns 0 if following the symlink is allowed, -ve on error.
*/
-static inline int may_follow_link(struct path *link, struct nameidata *nd)
+static inline int may_follow_link(struct nameidata *nd)
{
const struct inode *inode;
const struct inode *parent;
return 0;
/* Allowed if owner and follower match. */
- inode = link->dentry->d_inode;
+ inode = nd->stack[0].inode;
if (uid_eq(current_cred()->fsuid, inode->i_uid))
return 0;
/* Allowed if parent directory not sticky and world-writable. */
- parent = nd->path.dentry->d_inode;
+ parent = nd->inode;
if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
return 0;
if (uid_eq(parent->i_uid, inode->i_uid))
return 0;
- audit_log_link_denied("follow_link", link);
- path_put_conditional(link, nd);
- path_put(&nd->path);
+ if (nd->flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ audit_log_link_denied("follow_link", &nd->stack[0].link);
return -EACCES;
}
* - sysctl_protected_hardlinks enabled
* - fsuid does not match inode
* - hardlink source is unsafe (see safe_hardlink_source() above)
- * - not CAP_FOWNER
+ * - not CAP_FOWNER in a namespace with the inode owner uid mapped
*
* Returns 0 if successful, -ve on error.
*/
static int may_linkat(struct path *link)
{
- const struct cred *cred;
struct inode *inode;
if (!sysctl_protected_hardlinks)
return 0;
- cred = current_cred();
inode = link->dentry->d_inode;
/* Source inode owner (or CAP_FOWNER) can hardlink all they like,
* otherwise, it must be a safe source.
*/
- if (uid_eq(cred->fsuid, inode->i_uid) || safe_hardlink_source(inode) ||
- capable(CAP_FOWNER))
+ if (inode_owner_or_capable(inode) || safe_hardlink_source(inode))
return 0;
audit_log_link_denied("linkat", link);
return -EPERM;
}
-static __always_inline int
-follow_link(struct path *link, struct nameidata *nd, void **p)
+static __always_inline
+const char *get_link(struct nameidata *nd)
{
- struct dentry *dentry = link->dentry;
+ struct saved *last = nd->stack + nd->depth - 1;
+ struct dentry *dentry = last->link.dentry;
+ struct inode *inode = last->inode;
int error;
- char *s;
-
- BUG_ON(nd->flags & LOOKUP_RCU);
-
- if (link->mnt == nd->path.mnt)
- mntget(link->mnt);
-
- error = -ELOOP;
- if (unlikely(current->total_link_count >= 40))
- goto out_put_nd_path;
-
- cond_resched();
- current->total_link_count++;
+ const char *res;
- touch_atime(link);
- nd_set_link(nd, NULL);
+ if (!(nd->flags & LOOKUP_RCU)) {
+ touch_atime(&last->link);
+ cond_resched();
+ } else if (atime_needs_update(&last->link, inode)) {
+ if (unlikely(unlazy_walk(nd, NULL, 0)))
+ return ERR_PTR(-ECHILD);
+ touch_atime(&last->link);
+ }
- error = security_inode_follow_link(link->dentry, nd);
- if (error)
- goto out_put_nd_path;
+ error = security_inode_follow_link(dentry, inode,
+ nd->flags & LOOKUP_RCU);
+ if (unlikely(error))
+ return ERR_PTR(error);
nd->last_type = LAST_BIND;
- *p = dentry->d_inode->i_op->follow_link(dentry, nd);
- error = PTR_ERR(*p);
- if (IS_ERR(*p))
- goto out_put_nd_path;
-
- error = 0;
- s = nd_get_link(nd);
- if (s) {
- if (unlikely(IS_ERR(s))) {
- path_put(&nd->path);
- put_link(nd, link, *p);
- return PTR_ERR(s);
+ res = inode->i_link;
+ if (!res) {
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlikely(unlazy_walk(nd, NULL, 0)))
+ return ERR_PTR(-ECHILD);
+ }
+ res = inode->i_op->follow_link(dentry, &last->cookie);
+ if (IS_ERR_OR_NULL(res)) {
+ last->cookie = NULL;
+ return res;
}
- if (*s == '/') {
+ }
+ if (*res == '/') {
+ if (nd->flags & LOOKUP_RCU) {
+ struct dentry *d;
+ if (!nd->root.mnt)
+ set_root_rcu(nd);
+ nd->path = nd->root;
+ d = nd->path.dentry;
+ nd->inode = d->d_inode;
+ nd->seq = nd->root_seq;
+ if (unlikely(read_seqcount_retry(&d->d_seq, nd->seq)))
+ return ERR_PTR(-ECHILD);
+ } else {
if (!nd->root.mnt)
set_root(nd);
path_put(&nd->path);
nd->path = nd->root;
path_get(&nd->root);
- nd->flags |= LOOKUP_JUMPED;
+ nd->inode = nd->path.dentry->d_inode;
}
- nd->inode = nd->path.dentry->d_inode;
- error = link_path_walk(s, nd);
- if (unlikely(error))
- put_link(nd, link, *p);
+ nd->flags |= LOOKUP_JUMPED;
+ while (unlikely(*++res == '/'))
+ ;
}
-
- return error;
-
-out_put_nd_path:
- *p = NULL;
- path_put(&nd->path);
- path_put(link);
- return error;
-}
-
-static int follow_up_rcu(struct path *path)
-{
- struct mount *mnt = real_mount(path->mnt);
- struct mount *parent;
- struct dentry *mountpoint;
-
- parent = mnt->mnt_parent;
- if (&parent->mnt == path->mnt)
- return 0;
- mountpoint = mnt->mnt_mountpoint;
- path->dentry = mountpoint;
- path->mnt = &parent->mnt;
- return 1;
+ if (!*res)
+ res = NULL;
+ return res;
}
/*
* - return -EISDIR to tell follow_managed() to stop and return the path we
* were called with.
*/
-static int follow_automount(struct path *path, unsigned flags,
+static int follow_automount(struct path *path, struct nameidata *nd,
bool *need_mntput)
{
struct vfsmount *mnt;
* as being automount points. These will need the attentions
* of the daemon to instantiate them before they can be used.
*/
- if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
- LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
+ if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
+ LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
path->dentry->d_inode)
return -EISDIR;
- current->total_link_count++;
- if (current->total_link_count >= 40)
+ nd->total_link_count++;
+ if (nd->total_link_count >= 40)
return -ELOOP;
mnt = path->dentry->d_op->d_automount(path);
* the path being looked up; if it wasn't then the remainder of
* the path is inaccessible and we should say so.
*/
- if (PTR_ERR(mnt) == -EISDIR && (flags & LOOKUP_PARENT))
+ if (PTR_ERR(mnt) == -EISDIR && (nd->flags & LOOKUP_PARENT))
return -EREMOTE;
return PTR_ERR(mnt);
}
*
* Serialization is taken care of in namespace.c
*/
-static int follow_managed(struct path *path, unsigned flags)
+static int follow_managed(struct path *path, struct nameidata *nd)
{
struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */
unsigned managed;
/* Handle an automount point */
if (managed & DCACHE_NEED_AUTOMOUNT) {
- ret = follow_automount(path, flags, &need_mntput);
+ ret = follow_automount(path, nd, &need_mntput);
if (ret < 0)
break;
continue;
mntput(path->mnt);
if (ret == -EISDIR)
ret = 0;
- return ret < 0 ? ret : need_mntput;
+ if (need_mntput)
+ nd->flags |= LOOKUP_JUMPED;
+ if (unlikely(ret < 0))
+ path_put_conditional(path, nd);
+ return ret;
}
int follow_down_one(struct path *path)
* we meet a managed dentry that would need blocking.
*/
static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
- struct inode **inode)
+ struct inode **inode, unsigned *seqp)
{
for (;;) {
struct mount *mounted;
path->mnt = &mounted->mnt;
path->dentry = mounted->mnt.mnt_root;
nd->flags |= LOOKUP_JUMPED;
- nd->seq = read_seqcount_begin(&path->dentry->d_seq);
+ *seqp = read_seqcount_begin(&path->dentry->d_seq);
/*
* Update the inode too. We don't need to re-check the
* dentry sequence number here after this d_inode read,
set_root_rcu(nd);
while (1) {
- if (nd->path.dentry == nd->root.dentry &&
- nd->path.mnt == nd->root.mnt) {
+ if (path_equal(&nd->path, &nd->root))
break;
- }
if (nd->path.dentry != nd->path.mnt->mnt_root) {
struct dentry *old = nd->path.dentry;
struct dentry *parent = old->d_parent;
inode = parent->d_inode;
seq = read_seqcount_begin(&parent->d_seq);
- if (read_seqcount_retry(&old->d_seq, nd->seq))
- goto failed;
+ if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq)))
+ return -ECHILD;
nd->path.dentry = parent;
nd->seq = seq;
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
+ } else {
+ struct mount *mnt = real_mount(nd->path.mnt);
+ struct mount *mparent = mnt->mnt_parent;
+ struct dentry *mountpoint = mnt->mnt_mountpoint;
+ struct inode *inode2 = mountpoint->d_inode;
+ unsigned seq = read_seqcount_begin(&mountpoint->d_seq);
+ if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
+ return -ECHILD;
+ if (&mparent->mnt == nd->path.mnt)
+ break;
+ /* we know that mountpoint was pinned */
+ nd->path.dentry = mountpoint;
+ nd->path.mnt = &mparent->mnt;
+ inode = inode2;
+ nd->seq = seq;
}
- if (!follow_up_rcu(&nd->path))
- break;
- inode = nd->path.dentry->d_inode;
- nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
}
- while (d_mountpoint(nd->path.dentry)) {
+ while (unlikely(d_mountpoint(nd->path.dentry))) {
struct mount *mounted;
mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);
+ if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))
+ return -ECHILD;
if (!mounted)
break;
nd->path.mnt = &mounted->mnt;
nd->path.dentry = mounted->mnt.mnt_root;
inode = nd->path.dentry->d_inode;
nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
- if (read_seqretry(&mount_lock, nd->m_seq))
- goto failed;
}
nd->inode = inode;
return 0;
-
-failed:
- nd->flags &= ~LOOKUP_RCU;
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
- rcu_read_unlock();
- return -ECHILD;
}
/*
}
}
-static void follow_dotdot(struct nameidata *nd)
+static int follow_dotdot(struct nameidata *nd)
{
if (!nd->root.mnt)
set_root(nd);
/* rare case of legitimate dget_parent()... */
nd->path.dentry = dget_parent(nd->path.dentry);
dput(old);
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
}
if (!follow_up(&nd->path))
}
follow_mount(&nd->path);
nd->inode = nd->path.dentry->d_inode;
+ return 0;
}
/*
* It _is_ time-critical.
*/
static int lookup_fast(struct nameidata *nd,
- struct path *path, struct inode **inode)
+ struct path *path, struct inode **inode,
+ unsigned *seqp)
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry, *parent = nd->path.dentry;
* This sequence count validates that the inode matches
* the dentry name information from lookup.
*/
- *inode = dentry->d_inode;
+ *inode = d_backing_inode(dentry);
negative = d_is_negative(dentry);
if (read_seqcount_retry(&dentry->d_seq, seq))
return -ECHILD;
- if (negative)
- return -ENOENT;
/*
* This sequence count validates that the parent had no
*/
if (__read_seqcount_retry(&parent->d_seq, nd->seq))
return -ECHILD;
- nd->seq = seq;
+ *seqp = seq;
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
status = d_revalidate(dentry, nd->flags);
if (unlikely(status <= 0)) {
goto unlazy;
}
}
+ /*
+ * Note: do negative dentry check after revalidation in
+ * case that drops it.
+ */
+ if (negative)
+ return -ENOENT;
path->mnt = mnt;
path->dentry = dentry;
- if (likely(__follow_mount_rcu(nd, path, inode)))
+ if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
return 0;
unlazy:
- if (unlazy_walk(nd, dentry))
+ if (unlazy_walk(nd, dentry, seq))
return -ECHILD;
} else {
dentry = __d_lookup(parent, &nd->last);
}
path->mnt = mnt;
path->dentry = dentry;
- err = follow_managed(path, nd->flags);
- if (unlikely(err < 0)) {
- path_put_conditional(path, nd);
- return err;
- }
- if (err)
- nd->flags |= LOOKUP_JUMPED;
- *inode = path->dentry->d_inode;
- return 0;
+ err = follow_managed(path, nd);
+ if (likely(!err))
+ *inode = d_backing_inode(path->dentry);
+ return err;
need_lookup:
return 1;
static int lookup_slow(struct nameidata *nd, struct path *path)
{
struct dentry *dentry, *parent;
- int err;
parent = nd->path.dentry;
BUG_ON(nd->inode != parent->d_inode);
return PTR_ERR(dentry);
path->mnt = nd->path.mnt;
path->dentry = dentry;
- err = follow_managed(path, nd->flags);
- if (unlikely(err < 0)) {
- path_put_conditional(path, nd);
- return err;
- }
- if (err)
- nd->flags |= LOOKUP_JUMPED;
- return 0;
+ return follow_managed(path, nd);
}
static inline int may_lookup(struct nameidata *nd)
int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK);
if (err != -ECHILD)
return err;
- if (unlazy_walk(nd, NULL))
+ if (unlazy_walk(nd, NULL, 0))
return -ECHILD;
}
return inode_permission(nd->inode, MAY_EXEC);
{
if (type == LAST_DOTDOT) {
if (nd->flags & LOOKUP_RCU) {
- if (follow_dotdot_rcu(nd))
- return -ECHILD;
+ return follow_dotdot_rcu(nd);
} else
- follow_dotdot(nd);
+ return follow_dotdot(nd);
}
return 0;
}
-static void terminate_walk(struct nameidata *nd)
+static int pick_link(struct nameidata *nd, struct path *link,
+ struct inode *inode, unsigned seq)
{
+ int error;
+ struct saved *last;
+ if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) {
+ path_to_nameidata(link, nd);
+ return -ELOOP;
+ }
if (!(nd->flags & LOOKUP_RCU)) {
- path_put(&nd->path);
- } else {
- nd->flags &= ~LOOKUP_RCU;
- if (!(nd->flags & LOOKUP_ROOT))
- nd->root.mnt = NULL;
- rcu_read_unlock();
+ if (link->mnt == nd->path.mnt)
+ mntget(link->mnt);
+ }
+ error = nd_alloc_stack(nd);
+ if (unlikely(error)) {
+ if (error == -ECHILD) {
+ if (unlikely(unlazy_link(nd, link, seq)))
+ return -ECHILD;
+ error = nd_alloc_stack(nd);
+ }
+ if (error) {
+ path_put(link);
+ return error;
+ }
}
+
+ last = nd->stack + nd->depth++;
+ last->link = *link;
+ last->cookie = NULL;
+ last->inode = inode;
+ last->seq = seq;
+ return 1;
}
/*
* so we keep a cache of "no, this doesn't need follow_link"
* for the common case.
*/
-static inline int should_follow_link(struct dentry *dentry, int follow)
+static inline int should_follow_link(struct nameidata *nd, struct path *link,
+ int follow,
+ struct inode *inode, unsigned seq)
{
- return unlikely(d_is_symlink(dentry)) ? follow : 0;
+ if (likely(!d_is_symlink(link->dentry)))
+ return 0;
+ if (!follow)
+ return 0;
+ /* make sure that d_is_symlink above matches inode */
+ if (nd->flags & LOOKUP_RCU) {
+ if (read_seqcount_retry(&link->dentry->d_seq, seq))
+ return -ECHILD;
+ }
+ return pick_link(nd, link, inode, seq);
}
-static inline int walk_component(struct nameidata *nd, struct path *path,
- int follow)
+enum {WALK_GET = 1, WALK_PUT = 2};
+
+static int walk_component(struct nameidata *nd, int flags)
{
+ struct path path;
struct inode *inode;
+ unsigned seq;
int err;
/*
* "." and ".." are special - ".." especially so because it has
* to be able to know about the current root directory and
* parent relationships.
*/
- if (unlikely(nd->last_type != LAST_NORM))
- return handle_dots(nd, nd->last_type);
- err = lookup_fast(nd, path, &inode);
+ if (unlikely(nd->last_type != LAST_NORM)) {
+ err = handle_dots(nd, nd->last_type);
+ if (flags & WALK_PUT)
+ put_link(nd);
+ return err;
+ }
+ err = lookup_fast(nd, &path, &inode, &seq);
if (unlikely(err)) {
if (err < 0)
- goto out_err;
+ return err;
- err = lookup_slow(nd, path);
+ err = lookup_slow(nd, &path);
if (err < 0)
- goto out_err;
+ return err;
- inode = path->dentry->d_inode;
+ seq = 0; /* we are already out of RCU mode */
err = -ENOENT;
- if (d_is_negative(path->dentry))
+ if (d_is_negative(path.dentry))
goto out_path_put;
+ inode = d_backing_inode(path.dentry);
}
- if (should_follow_link(path->dentry, follow)) {
- if (nd->flags & LOOKUP_RCU) {
- if (unlikely(nd->path.mnt != path->mnt ||
- unlazy_walk(nd, path->dentry))) {
- err = -ECHILD;
- goto out_err;
- }
- }
- BUG_ON(inode != path->dentry->d_inode);
- return 1;
- }
- path_to_nameidata(path, nd);
+ if (flags & WALK_PUT)
+ put_link(nd);
+ err = should_follow_link(nd, &path, flags & WALK_GET, inode, seq);
+ if (unlikely(err))
+ return err;
+ path_to_nameidata(&path, nd);
nd->inode = inode;
+ nd->seq = seq;
return 0;
out_path_put:
- path_to_nameidata(path, nd);
-out_err:
- terminate_walk(nd);
+ path_to_nameidata(&path, nd);
return err;
}
-/*
- * This limits recursive symlink follows to 8, while
- * limiting consecutive symlinks to 40.
- *
- * Without that kind of total limit, nasty chains of consecutive
- * symlinks can cause almost arbitrarily long lookups.
- */
-static inline int nested_symlink(struct path *path, struct nameidata *nd)
-{
- int res;
-
- if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
- path_put_conditional(path, nd);
- path_put(&nd->path);
- return -ELOOP;
- }
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
-
- nd->depth++;
- current->link_count++;
-
- do {
- struct path link = *path;
- void *cookie;
-
- res = follow_link(&link, nd, &cookie);
- if (res)
- break;
- res = walk_component(nd, path, LOOKUP_FOLLOW);
- put_link(nd, &link, cookie);
- } while (res > 0);
-
- current->link_count--;
- nd->depth--;
- return res;
-}
-
/*
* We can do the critical dentry name comparison and hashing
* operations one word at a time, but we are limited to:
*/
static int link_path_walk(const char *name, struct nameidata *nd)
{
- struct path next;
int err;
-
+
while (*name=='/')
name++;
if (!*name)
err = may_lookup(nd);
if (err)
- break;
+ return err;
hash_len = hash_name(name);
struct qstr this = { { .hash_len = hash_len }, .name = name };
err = parent->d_op->d_hash(parent, &this);
if (err < 0)
- break;
+ return err;
hash_len = this.hash_len;
name = this.name;
}
name += hashlen_len(hash_len);
if (!*name)
- return 0;
+ goto OK;
/*
* If it wasn't NUL, we know it was '/'. Skip that
* slash, and continue until no more slashes.
do {
name++;
} while (unlikely(*name == '/'));
- if (!*name)
- return 0;
-
- err = walk_component(nd, &next, LOOKUP_FOLLOW);
+ if (unlikely(!*name)) {
+OK:
+ /* pathname body, done */
+ if (!nd->depth)
+ return 0;
+ name = nd->stack[nd->depth - 1].name;
+ /* trailing symlink, done */
+ if (!name)
+ return 0;
+ /* last component of nested symlink */
+ err = walk_component(nd, WALK_GET | WALK_PUT);
+ } else {
+ err = walk_component(nd, WALK_GET);
+ }
if (err < 0)
return err;
if (err) {
- err = nested_symlink(&next, nd);
- if (err)
- return err;
+ const char *s = get_link(nd);
+
+ if (IS_ERR(s))
+ return PTR_ERR(s);
+ err = 0;
+ if (unlikely(!s)) {
+ /* jumped */
+ put_link(nd);
+ } else {
+ nd->stack[nd->depth - 1].name = name;
+ name = s;
+ continue;
+ }
}
- if (!d_can_lookup(nd->path.dentry)) {
- err = -ENOTDIR;
- break;
+ if (unlikely(!d_can_lookup(nd->path.dentry))) {
+ if (nd->flags & LOOKUP_RCU) {
+ if (unlazy_walk(nd, NULL, 0))
+ return -ECHILD;
+ }
+ return -ENOTDIR;
}
}
- terminate_walk(nd);
- return err;
}
-static int path_init(int dfd, const struct filename *name, unsigned int flags,
- struct nameidata *nd)
+static const char *path_init(struct nameidata *nd, unsigned flags)
{
int retval = 0;
- const char *s = name->name;
+ const char *s = nd->name->name;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
nd->depth = 0;
- nd->base = NULL;
if (flags & LOOKUP_ROOT) {
struct dentry *root = nd->root.dentry;
struct inode *inode = root->d_inode;
if (*s) {
if (!d_can_lookup(root))
- return -ENOTDIR;
+ return ERR_PTR(-ENOTDIR);
retval = inode_permission(inode, MAY_EXEC);
if (retval)
- return retval;
+ return ERR_PTR(retval);
}
nd->path = nd->root;
nd->inode = inode;
if (flags & LOOKUP_RCU) {
rcu_read_lock();
nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
+ nd->root_seq = nd->seq;
nd->m_seq = read_seqbegin(&mount_lock);
} else {
path_get(&nd->path);
}
- goto done;
+ return s;
}
nd->root.mnt = NULL;
if (*s == '/') {
if (flags & LOOKUP_RCU) {
rcu_read_lock();
- nd->seq = set_root_rcu(nd);
+ set_root_rcu(nd);
+ nd->seq = nd->root_seq;
} else {
set_root(nd);
path_get(&nd->root);
}
nd->path = nd->root;
- } else if (dfd == AT_FDCWD) {
+ } else if (nd->dfd == AT_FDCWD) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
}
} else {
/* Caller must check execute permissions on the starting path component */
- struct fd f = fdget_raw(dfd);
+ struct fd f = fdget_raw(nd->dfd);
struct dentry *dentry;
if (!f.file)
- return -EBADF;
+ return ERR_PTR(-EBADF);
dentry = f.file->f_path.dentry;
if (*s) {
if (!d_can_lookup(dentry)) {
fdput(f);
- return -ENOTDIR;
+ return ERR_PTR(-ENOTDIR);
}
}
nd->path = f.file->f_path;
if (flags & LOOKUP_RCU) {
- if (f.flags & FDPUT_FPUT)
- nd->base = f.file;
- nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
rcu_read_lock();
+ nd->inode = nd->path.dentry->d_inode;
+ nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
} else {
path_get(&nd->path);
- fdput(f);
+ nd->inode = nd->path.dentry->d_inode;
}
+ fdput(f);
+ return s;
}
nd->inode = nd->path.dentry->d_inode;
if (!(flags & LOOKUP_RCU))
- goto done;
+ return s;
if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
- goto done;
+ return s;
if (!(nd->flags & LOOKUP_ROOT))
nd->root.mnt = NULL;
rcu_read_unlock();
- return -ECHILD;
-done:
- current->total_link_count = 0;
- return link_path_walk(s, nd);
+ return ERR_PTR(-ECHILD);
}
-static void path_cleanup(struct nameidata *nd)
+static const char *trailing_symlink(struct nameidata *nd)
{
- if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
- path_put(&nd->root);
- nd->root.mnt = NULL;
- }
- if (unlikely(nd->base))
- fput(nd->base);
+ const char *s;
+ int error = may_follow_link(nd);
+ if (unlikely(error))
+ return ERR_PTR(error);
+ nd->flags |= LOOKUP_PARENT;
+ nd->stack[0].name = NULL;
+ s = get_link(nd);
+ return s ? s : "";
}
-static inline int lookup_last(struct nameidata *nd, struct path *path)
+static inline int lookup_last(struct nameidata *nd)
{
if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
nd->flags &= ~LOOKUP_PARENT;
- return walk_component(nd, path, nd->flags & LOOKUP_FOLLOW);
+ return walk_component(nd,
+ nd->flags & LOOKUP_FOLLOW
+ ? nd->depth
+ ? WALK_PUT | WALK_GET
+ : WALK_GET
+ : 0);
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
-static int path_lookupat(int dfd, const struct filename *name,
- unsigned int flags, struct nameidata *nd)
+static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path)
{
- struct path path;
+ const char *s = path_init(nd, flags);
int err;
- /*
- * Path walking is largely split up into 2 different synchronisation
- * schemes, rcu-walk and ref-walk (explained in
- * Documentation/filesystems/path-lookup.txt). These share much of the
- * path walk code, but some things particularly setup, cleanup, and
- * following mounts are sufficiently divergent that functions are
- * duplicated. Typically there is a function foo(), and its RCU
- * analogue, foo_rcu().
- *
- * -ECHILD is the error number of choice (just to avoid clashes) that
- * is returned if some aspect of an rcu-walk fails. Such an error must
- * be handled by restarting a traditional ref-walk (which will always
- * be able to complete).
- */
- err = path_init(dfd, name, flags, nd);
- if (!err && !(flags & LOOKUP_PARENT)) {
- err = lookup_last(nd, &path);
- while (err > 0) {
- void *cookie;
- struct path link = path;
- err = may_follow_link(&link, nd);
- if (unlikely(err))
- break;
- nd->flags |= LOOKUP_PARENT;
- err = follow_link(&link, nd, &cookie);
- if (err)
- break;
- err = lookup_last(nd, &path);
- put_link(nd, &link, cookie);
+ if (IS_ERR(s))
+ return PTR_ERR(s);
+ while (!(err = link_path_walk(s, nd))
+ && ((err = lookup_last(nd)) > 0)) {
+ s = trailing_symlink(nd);
+ if (IS_ERR(s)) {
+ err = PTR_ERR(s);
+ break;
}
}
-
if (!err)
err = complete_walk(nd);
- if (!err && nd->flags & LOOKUP_DIRECTORY) {
- if (!d_can_lookup(nd->path.dentry)) {
- path_put(&nd->path);
+ if (!err && nd->flags & LOOKUP_DIRECTORY)
+ if (!d_can_lookup(nd->path.dentry))
err = -ENOTDIR;
- }
+ if (!err) {
+ *path = nd->path;
+ nd->path.mnt = NULL;
+ nd->path.dentry = NULL;
}
-
- path_cleanup(nd);
+ terminate_walk(nd);
return err;
}
-static int filename_lookup(int dfd, struct filename *name,
- unsigned int flags, struct nameidata *nd)
+static int filename_lookup(int dfd, struct filename *name, unsigned flags,
+ struct path *path, struct path *root)
{
- int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+ int retval;
+ struct nameidata nd;
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+ if (unlikely(root)) {
+ nd.root = *root;
+ flags |= LOOKUP_ROOT;
+ }
+ set_nameidata(&nd, dfd, name);
+ retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
- retval = path_lookupat(dfd, name, flags, nd);
+ retval = path_lookupat(&nd, flags, path);
if (unlikely(retval == -ESTALE))
- retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+ retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path);
if (likely(!retval))
- audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT);
+ audit_inode(name, path->dentry, flags & LOOKUP_PARENT);
+ restore_nameidata();
+ putname(name);
return retval;
}
+/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
+static int path_parentat(struct nameidata *nd, unsigned flags,
+ struct path *parent)
+{
+ const char *s = path_init(nd, flags);
+ int err;
+ if (IS_ERR(s))
+ return PTR_ERR(s);
+ err = link_path_walk(s, nd);
+ if (!err)
+ err = complete_walk(nd);
+ if (!err) {
+ *parent = nd->path;
+ nd->path.mnt = NULL;
+ nd->path.dentry = NULL;
+ }
+ terminate_walk(nd);
+ return err;
+}
+
+static struct filename *filename_parentat(int dfd, struct filename *name,
+ unsigned int flags, struct path *parent,
+ struct qstr *last, int *type)
+{
+ int retval;
+ struct nameidata nd;
+
+ if (IS_ERR(name))
+ return name;
+ set_nameidata(&nd, dfd, name);
+ retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
+ if (unlikely(retval == -ECHILD))
+ retval = path_parentat(&nd, flags, parent);
+ if (unlikely(retval == -ESTALE))
+ retval = path_parentat(&nd, flags | LOOKUP_REVAL, parent);
+ if (likely(!retval)) {
+ *last = nd.last;
+ *type = nd.last_type;
+ audit_inode(name, parent->dentry, LOOKUP_PARENT);
+ } else {
+ putname(name);
+ name = ERR_PTR(retval);
+ }
+ restore_nameidata();
+ return name;
+}
+
/* does lookup, returns the object with parent locked */
struct dentry *kern_path_locked(const char *name, struct path *path)
{
- struct filename *filename = getname_kernel(name);
- struct nameidata nd;
+ struct filename *filename;
struct dentry *d;
- int err;
+ struct qstr last;
+ int type;
+ filename = filename_parentat(AT_FDCWD, getname_kernel(name), 0, path,
+ &last, &type);
if (IS_ERR(filename))
return ERR_CAST(filename);
-
- err = filename_lookup(AT_FDCWD, filename, LOOKUP_PARENT, &nd);
- if (err) {
- d = ERR_PTR(err);
- goto out;
- }
- if (nd.last_type != LAST_NORM) {
- path_put(&nd.path);
- d = ERR_PTR(-EINVAL);
- goto out;
+ if (unlikely(type != LAST_NORM)) {
+ path_put(path);
+ putname(filename);
+ return ERR_PTR(-EINVAL);
}
- mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- d = __lookup_hash(&nd.last, nd.path.dentry, 0);
+ mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+ d = __lookup_hash(&last, path->dentry, 0);
if (IS_ERR(d)) {
- mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
- path_put(&nd.path);
- goto out;
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
+ path_put(path);
}
- *path = nd.path;
-out:
putname(filename);
return d;
}
int kern_path(const char *name, unsigned int flags, struct path *path)
{
- struct nameidata nd;
- struct filename *filename = getname_kernel(name);
- int res = PTR_ERR(filename);
-
- if (!IS_ERR(filename)) {
- res = filename_lookup(AT_FDCWD, filename, flags, &nd);
- putname(filename);
- if (!res)
- *path = nd.path;
- }
- return res;
+ return filename_lookup(AT_FDCWD, getname_kernel(name),
+ flags, path, NULL);
}
EXPORT_SYMBOL(kern_path);
const char *name, unsigned int flags,
struct path *path)
{
- struct filename *filename = getname_kernel(name);
- int err = PTR_ERR(filename);
-
- BUG_ON(flags & LOOKUP_PARENT);
-
- /* the first argument of filename_lookup() is ignored with LOOKUP_ROOT */
- if (!IS_ERR(filename)) {
- struct nameidata nd;
- nd.root.dentry = dentry;
- nd.root.mnt = mnt;
- err = filename_lookup(AT_FDCWD, filename,
- flags | LOOKUP_ROOT, &nd);
- if (!err)
- *path = nd.path;
- putname(filename);
- }
- return err;
+ struct path root = {.mnt = mnt, .dentry = dentry};
+ /* the first argument of filename_lookup() is ignored with root */
+ return filename_lookup(AT_FDCWD, getname_kernel(name),
+ flags , path, &root);
}
EXPORT_SYMBOL(vfs_path_lookup);
-/*
- * Restricted form of lookup. Doesn't follow links, single-component only,
- * needs parent already locked. Doesn't follow mounts.
- * SMP-safe.
- */
-static struct dentry *lookup_hash(struct nameidata *nd)
-{
- return __lookup_hash(&nd->last, nd->path.dentry, nd->flags);
-}
-
/**
* lookup_one_len - filesystem helper to lookup single pathname component
* @name: pathname component to lookup
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
- struct nameidata nd;
- struct filename *tmp = getname_flags(name, flags, empty);
- int err = PTR_ERR(tmp);
- if (!IS_ERR(tmp)) {
-
- BUG_ON(flags & LOOKUP_PARENT);
-
- err = filename_lookup(dfd, tmp, flags, &nd);
- putname(tmp);
- if (!err)
- *path = nd.path;
- }
- return err;
+ return filename_lookup(dfd, getname_flags(name, flags, empty),
+ flags, path, NULL);
}
-
-int user_path_at(int dfd, const char __user *name, unsigned flags,
- struct path *path)
-{
- return user_path_at_empty(dfd, name, flags, path, NULL);
-}
-EXPORT_SYMBOL(user_path_at);
+EXPORT_SYMBOL(user_path_at_empty);
/*
* NB: most callers don't do anything directly with the reference to the
* allocated by getname. So we must hold the reference to it until all
* path-walking is complete.
*/
-static struct filename *
-user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
+static inline struct filename *
+user_path_parent(int dfd, const char __user *path,
+ struct path *parent,
+ struct qstr *last,
+ int *type,
unsigned int flags)
{
- struct filename *s = getname(path);
- int error;
-
/* only LOOKUP_REVAL is allowed in extra flags */
- flags &= LOOKUP_REVAL;
-
- if (IS_ERR(s))
- return s;
-
- error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd);
- if (error) {
- putname(s);
- return ERR_PTR(error);
- }
-
- return s;
+ return filename_parentat(dfd, getname(path), flags & LOOKUP_REVAL,
+ parent, last, type);
}
/**
/* If we're in rcuwalk, drop out of it to handle last component */
if (nd->flags & LOOKUP_RCU) {
- if (unlazy_walk(nd, NULL)) {
- error = -ECHILD;
- goto out;
- }
+ if (unlazy_walk(nd, NULL, 0))
+ return -ECHILD;
}
nd->flags &= ~LOOKUP_PARENT;
if (unlikely(nd->last_type != LAST_NORM)) {
error = handle_dots(nd, nd->last_type);
if (error)
- goto out;
+ return error;
dentry = dget(nd->path.dentry);
goto done;
}
*/
dentry = d_alloc(dir, &nd->last);
if (!dentry) {
- error = -ENOMEM;
mutex_unlock(&dir->d_inode->i_mutex);
- goto out;
+ return -ENOMEM;
}
dentry = lookup_real(dir->d_inode, dentry, nd->flags);
- error = PTR_ERR(dentry);
if (IS_ERR(dentry)) {
mutex_unlock(&dir->d_inode->i_mutex);
- goto out;
+ return PTR_ERR(dentry);
}
}
mutex_unlock(&dir->d_inode->i_mutex);
done:
if (d_is_negative(dentry)) {
- error = -ENOENT;
dput(dentry);
- goto out;
+ return -ENOENT;
}
+ if (nd->depth)
+ put_link(nd);
path->dentry = dentry;
path->mnt = nd->path.mnt;
- if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW))
- return 1;
+ error = should_follow_link(nd, path, nd->flags & LOOKUP_FOLLOW,
+ d_backing_inode(dentry), 0);
+ if (unlikely(error))
+ return error;
mntget(path->mnt);
follow_mount(path);
- error = 0;
-out:
- terminate_walk(nd);
- return error;
+ return 0;
}
/**
* path_mountpoint - look up a path to be umounted
- * @dfd: directory file descriptor to start walk from
- * @name: full pathname to walk
- * @path: pointer to container for result
+ * @nd: lookup context
* @flags: lookup flags
+ * @path: pointer to container for result
*
* Look up the given name, but don't attempt to revalidate the last component.
* Returns 0 and "path" will be valid on success; Returns error otherwise.
*/
static int
-path_mountpoint(int dfd, const struct filename *name, struct path *path,
- unsigned int flags)
+path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path)
{
- struct nameidata nd;
+ const char *s = path_init(nd, flags);
int err;
-
- err = path_init(dfd, name, flags, &nd);
- if (unlikely(err))
- goto out;
-
- err = mountpoint_last(&nd, path);
- while (err > 0) {
- void *cookie;
- struct path link = *path;
- err = may_follow_link(&link, &nd);
- if (unlikely(err))
- break;
- nd.flags |= LOOKUP_PARENT;
- err = follow_link(&link, &nd, &cookie);
- if (err)
+ if (IS_ERR(s))
+ return PTR_ERR(s);
+ while (!(err = link_path_walk(s, nd)) &&
+ (err = mountpoint_last(nd, path)) > 0) {
+ s = trailing_symlink(nd);
+ if (IS_ERR(s)) {
+ err = PTR_ERR(s);
break;
- err = mountpoint_last(&nd, path);
- put_link(&nd, &link, cookie);
+ }
}
-out:
- path_cleanup(&nd);
+ terminate_walk(nd);
return err;
}
filename_mountpoint(int dfd, struct filename *name, struct path *path,
unsigned int flags)
{
+ struct nameidata nd;
int error;
if (IS_ERR(name))
return PTR_ERR(name);
- error = path_mountpoint(dfd, name, path, flags | LOOKUP_RCU);
+ set_nameidata(&nd, dfd, name);
+ error = path_mountpoint(&nd, flags | LOOKUP_RCU, path);
if (unlikely(error == -ECHILD))
- error = path_mountpoint(dfd, name, path, flags);
+ error = path_mountpoint(&nd, flags, path);
if (unlikely(error == -ESTALE))
- error = path_mountpoint(dfd, name, path, flags | LOOKUP_REVAL);
+ error = path_mountpoint(&nd, flags | LOOKUP_REVAL, path);
if (likely(!error))
audit_inode(name, path->dentry, 0);
+ restore_nameidata();
putname(name);
return error;
}
*/
static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
{
- struct inode *inode = victim->d_inode;
+ struct inode *inode = d_backing_inode(victim);
int error;
if (d_is_negative(victim))
/*
* Handle the last step of open()
*/
-static int do_last(struct nameidata *nd, struct path *path,
+static int do_last(struct nameidata *nd,
struct file *file, const struct open_flags *op,
- int *opened, struct filename *name)
+ int *opened)
{
struct dentry *dir = nd->path.dentry;
int open_flag = op->open_flag;
bool will_truncate = (open_flag & O_TRUNC) != 0;
bool got_write = false;
int acc_mode = op->acc_mode;
+ unsigned seq;
struct inode *inode;
- bool symlink_ok = false;
struct path save_parent = { .dentry = NULL, .mnt = NULL };
+ struct path path;
bool retried = false;
int error;
if (nd->last_type != LAST_NORM) {
error = handle_dots(nd, nd->last_type);
- if (error)
+ if (unlikely(error))
return error;
goto finish_open;
}
if (!(open_flag & O_CREAT)) {
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
- if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
- symlink_ok = true;
/* we _can_ be in RCU mode here */
- error = lookup_fast(nd, path, &inode);
+ error = lookup_fast(nd, &path, &inode, &seq);
if (likely(!error))
goto finish_lookup;
if (error < 0)
- goto out;
+ return error;
BUG_ON(nd->inode != dir->d_inode);
} else {
if (error)
return error;
- audit_inode(name, dir, LOOKUP_PARENT);
- error = -EISDIR;
+ audit_inode(nd->name, dir, LOOKUP_PARENT);
/* trailing slashes? */
- if (nd->last.name[nd->last.len])
- goto out;
+ if (unlikely(nd->last.name[nd->last.len]))
+ return -EISDIR;
}
retry_lookup:
*/
}
mutex_lock(&dir->d_inode->i_mutex);
- error = lookup_open(nd, path, file, op, got_write, opened);
+ error = lookup_open(nd, &path, file, op, got_write, opened);
mutex_unlock(&dir->d_inode->i_mutex);
if (error <= 0) {
!S_ISREG(file_inode(file)->i_mode))
will_truncate = false;
- audit_inode(name, file->f_path.dentry, 0);
+ audit_inode(nd->name, file->f_path.dentry, 0);
goto opened;
}
open_flag &= ~O_TRUNC;
will_truncate = false;
acc_mode = MAY_OPEN;
- path_to_nameidata(path, nd);
+ path_to_nameidata(&path, nd);
goto finish_open_created;
}
/*
* create/update audit record if it already exists.
*/
- if (d_is_positive(path->dentry))
- audit_inode(name, path->dentry, 0);
+ if (d_is_positive(path.dentry))
+ audit_inode(nd->name, path.dentry, 0);
/*
* If atomic_open() acquired write access it is dropped now due to
got_write = false;
}
- error = -EEXIST;
- if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))
- goto exit_dput;
-
- error = follow_managed(path, nd->flags);
- if (error < 0)
- goto exit_dput;
+ if (unlikely((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))) {
+ path_to_nameidata(&path, nd);
+ return -EEXIST;
+ }
- if (error)
- nd->flags |= LOOKUP_JUMPED;
+ error = follow_managed(&path, nd);
+ if (unlikely(error < 0))
+ return error;
BUG_ON(nd->flags & LOOKUP_RCU);
- inode = path->dentry->d_inode;
- error = -ENOENT;
- if (d_is_negative(path->dentry)) {
- path_to_nameidata(path, nd);
- goto out;
+ seq = 0; /* out of RCU mode, so the value doesn't matter */
+ if (unlikely(d_is_negative(path.dentry))) {
+ path_to_nameidata(&path, nd);
+ return -ENOENT;
}
+ inode = d_backing_inode(path.dentry);
finish_lookup:
- /* we _can_ be in RCU mode here */
- if (should_follow_link(path->dentry, !symlink_ok)) {
- if (nd->flags & LOOKUP_RCU) {
- if (unlikely(nd->path.mnt != path->mnt ||
- unlazy_walk(nd, path->dentry))) {
- error = -ECHILD;
- goto out;
- }
- }
- BUG_ON(inode != path->dentry->d_inode);
- return 1;
- }
+ if (nd->depth)
+ put_link(nd);
+ error = should_follow_link(nd, &path, nd->flags & LOOKUP_FOLLOW,
+ inode, seq);
+ if (unlikely(error))
+ return error;
- if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
- path_to_nameidata(path, nd);
+ if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path.mnt) {
+ path_to_nameidata(&path, nd);
} else {
save_parent.dentry = nd->path.dentry;
- save_parent.mnt = mntget(path->mnt);
- nd->path.dentry = path->dentry;
+ save_parent.mnt = mntget(path.mnt);
+ nd->path.dentry = path.dentry;
}
nd->inode = inode;
+ nd->seq = seq;
/* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */
finish_open:
error = complete_walk(nd);
path_put(&save_parent);
return error;
}
- audit_inode(name, nd->path.dentry, 0);
+ audit_inode(nd->name, nd->path.dentry, 0);
+ if (unlikely(d_is_symlink(nd->path.dentry)) && !(open_flag & O_PATH)) {
+ error = -ELOOP;
+ goto out;
+ }
error = -EISDIR;
if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry))
goto out;
goto exit_fput;
}
out:
+ if (unlikely(error > 0)) {
+ WARN_ON(1);
+ error = -EINVAL;
+ }
if (got_write)
mnt_drop_write(nd->path.mnt);
path_put(&save_parent);
- terminate_walk(nd);
return error;
-exit_dput:
- path_put_conditional(path, nd);
- goto out;
exit_fput:
fput(file);
goto out;
goto retry_lookup;
}
-static int do_tmpfile(int dfd, struct filename *pathname,
- struct nameidata *nd, int flags,
+static int do_tmpfile(struct nameidata *nd, unsigned flags,
const struct open_flags *op,
struct file *file, int *opened)
{
static const struct qstr name = QSTR_INIT("/", 1);
- struct dentry *dentry, *child;
+ struct dentry *child;
struct inode *dir;
- int error = path_lookupat(dfd, pathname,
- flags | LOOKUP_DIRECTORY, nd);
+ struct path path;
+ int error = path_lookupat(nd, flags | LOOKUP_DIRECTORY, &path);
if (unlikely(error))
return error;
- error = mnt_want_write(nd->path.mnt);
+ error = mnt_want_write(path.mnt);
if (unlikely(error))
goto out;
+ dir = path.dentry->d_inode;
/* we want directory to be writable */
- error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC);
+ error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
goto out2;
- dentry = nd->path.dentry;
- dir = dentry->d_inode;
if (!dir->i_op->tmpfile) {
error = -EOPNOTSUPP;
goto out2;
}
- child = d_alloc(dentry, &name);
+ child = d_alloc(path.dentry, &name);
if (unlikely(!child)) {
error = -ENOMEM;
goto out2;
}
- nd->flags &= ~LOOKUP_DIRECTORY;
- nd->flags |= op->intent;
- dput(nd->path.dentry);
- nd->path.dentry = child;
- error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode);
+ dput(path.dentry);
+ path.dentry = child;
+ error = dir->i_op->tmpfile(dir, child, op->mode);
if (error)
goto out2;
- audit_inode(pathname, nd->path.dentry, 0);
+ audit_inode(nd->name, child, 0);
/* Don't check for other permissions, the inode was just created */
- error = may_open(&nd->path, MAY_OPEN, op->open_flag);
+ error = may_open(&path, MAY_OPEN, op->open_flag);
if (error)
goto out2;
- file->f_path.mnt = nd->path.mnt;
- error = finish_open(file, nd->path.dentry, NULL, opened);
+ file->f_path.mnt = path.mnt;
+ error = finish_open(file, child, NULL, opened);
if (error)
goto out2;
error = open_check_o_direct(file);
spin_unlock(&inode->i_lock);
}
out2:
- mnt_drop_write(nd->path.mnt);
+ mnt_drop_write(path.mnt);
out:
- path_put(&nd->path);
+ path_put(&path);
return error;
}
-static struct file *path_openat(int dfd, struct filename *pathname,
- struct nameidata *nd, const struct open_flags *op, int flags)
+static struct file *path_openat(struct nameidata *nd,
+ const struct open_flags *op, unsigned flags)
{
+ const char *s;
struct file *file;
- struct path path;
int opened = 0;
int error;
file->f_flags = op->open_flag;
if (unlikely(file->f_flags & __O_TMPFILE)) {
- error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened);
+ error = do_tmpfile(nd, flags, op, file, &opened);
goto out2;
}
- error = path_init(dfd, pathname, flags, nd);
- if (unlikely(error))
- goto out;
-
- error = do_last(nd, &path, file, op, &opened, pathname);
- while (unlikely(error > 0)) { /* trailing symlink */
- struct path link = path;
- void *cookie;
- if (!(nd->flags & LOOKUP_FOLLOW)) {
- path_put_conditional(&path, nd);
- path_put(&nd->path);
- error = -ELOOP;
- break;
- }
- error = may_follow_link(&link, nd);
- if (unlikely(error))
- break;
- nd->flags |= LOOKUP_PARENT;
+ s = path_init(nd, flags);
+ if (IS_ERR(s)) {
+ put_filp(file);
+ return ERR_CAST(s);
+ }
+ while (!(error = link_path_walk(s, nd)) &&
+ (error = do_last(nd, file, op, &opened)) > 0) {
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
- error = follow_link(&link, nd, &cookie);
- if (unlikely(error))
+ s = trailing_symlink(nd);
+ if (IS_ERR(s)) {
+ error = PTR_ERR(s);
break;
- error = do_last(nd, &path, file, op, &opened, pathname);
- put_link(nd, &link, cookie);
+ }
}
-out:
- path_cleanup(nd);
+ terminate_walk(nd);
out2:
if (!(opened & FILE_OPENED)) {
BUG_ON(!error);
int flags = op->lookup_flags;
struct file *filp;
- filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU);
+ set_nameidata(&nd, dfd, pathname);
+ filp = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
- filp = path_openat(dfd, pathname, &nd, op, flags);
+ filp = path_openat(&nd, op, flags);
if (unlikely(filp == ERR_PTR(-ESTALE)))
- filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL);
+ filp = path_openat(&nd, op, flags | LOOKUP_REVAL);
+ restore_nameidata();
return filp;
}
return ERR_PTR(-ELOOP);
filename = getname_kernel(name);
- if (unlikely(IS_ERR(filename)))
+ if (IS_ERR(filename))
return ERR_CAST(filename);
- file = path_openat(-1, filename, &nd, op, flags | LOOKUP_RCU);
+ set_nameidata(&nd, -1, filename);
+ file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
- file = path_openat(-1, filename, &nd, op, flags);
+ file = path_openat(&nd, op, flags);
if (unlikely(file == ERR_PTR(-ESTALE)))
- file = path_openat(-1, filename, &nd, op, flags | LOOKUP_REVAL);
+ file = path_openat(&nd, op, flags | LOOKUP_REVAL);
+ restore_nameidata();
putname(filename);
return file;
}
struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
- struct nameidata nd;
+ struct qstr last;
+ int type;
int err2;
int error;
bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
*/
lookup_flags &= LOOKUP_REVAL;
- error = filename_lookup(dfd, name, LOOKUP_PARENT|lookup_flags, &nd);
- if (error)
- return ERR_PTR(error);
+ name = filename_parentat(dfd, name, lookup_flags, path, &last, &type);
+ if (IS_ERR(name))
+ return ERR_CAST(name);
/*
* Yucky last component or no last component at all?
* (foo/., foo/.., /////)
*/
- if (nd.last_type != LAST_NORM)
+ if (unlikely(type != LAST_NORM))
goto out;
- nd.flags &= ~LOOKUP_PARENT;
- nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL;
/* don't fail immediately if it's r/o, at least try to report other errors */
- err2 = mnt_want_write(nd.path.mnt);
+ err2 = mnt_want_write(path->mnt);
/*
* Do the final lookup.
*/
- mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
+ lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL;
+ mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+ dentry = __lookup_hash(&last, path->dentry, lookup_flags);
if (IS_ERR(dentry))
goto unlock;
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
- if (unlikely(!is_dir && nd.last.name[nd.last.len])) {
+ if (unlikely(!is_dir && last.name[last.len])) {
error = -ENOENT;
goto fail;
}
error = err2;
goto fail;
}
- *path = nd.path;
+ putname(name);
return dentry;
fail:
dput(dentry);
dentry = ERR_PTR(error);
unlock:
- mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+ mutex_unlock(&path->dentry->d_inode->i_mutex);
if (!err2)
- mnt_drop_write(nd.path.mnt);
+ mnt_drop_write(path->mnt);
out:
- path_put(&nd.path);
+ path_put(path);
+ putname(name);
return dentry;
}
struct dentry *kern_path_create(int dfd, const char *pathname,
struct path *path, unsigned int lookup_flags)
{
- struct filename *filename = getname_kernel(pathname);
- struct dentry *res;
-
- if (IS_ERR(filename))
- return ERR_CAST(filename);
- res = filename_create(dfd, filename, path, lookup_flags);
- putname(filename);
- return res;
+ return filename_create(dfd, getname_kernel(pathname),
+ path, lookup_flags);
}
EXPORT_SYMBOL(kern_path_create);
}
EXPORT_SYMBOL(done_path_create);
-struct dentry *user_path_create(int dfd, const char __user *pathname,
+inline struct dentry *user_path_create(int dfd, const char __user *pathname,
struct path *path, unsigned int lookup_flags)
{
- struct filename *tmp = getname(pathname);
- struct dentry *res;
- if (IS_ERR(tmp))
- return ERR_CAST(tmp);
- res = filename_create(dfd, tmp, path, lookup_flags);
- putname(tmp);
- return res;
+ return filename_create(dfd, getname(pathname), path, lookup_flags);
}
EXPORT_SYMBOL(user_path_create);
int error = 0;
struct filename *name;
struct dentry *dentry;
- struct nameidata nd;
+ struct path path;
+ struct qstr last;
+ int type;
unsigned int lookup_flags = 0;
retry:
- name = user_path_parent(dfd, pathname, &nd, lookup_flags);
+ name = user_path_parent(dfd, pathname,
+ &path, &last, &type, lookup_flags);
if (IS_ERR(name))
return PTR_ERR(name);
- switch(nd.last_type) {
+ switch (type) {
case LAST_DOTDOT:
error = -ENOTEMPTY;
goto exit1;
goto exit1;
}
- nd.flags &= ~LOOKUP_PARENT;
- error = mnt_want_write(nd.path.mnt);
+ error = mnt_want_write(path.mnt);
if (error)
goto exit1;
- mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
+ mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+ dentry = __lookup_hash(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto exit2;
error = -ENOENT;
goto exit3;
}
- error = security_path_rmdir(&nd.path, dentry);
+ error = security_path_rmdir(&path, dentry);
if (error)
goto exit3;
- error = vfs_rmdir(nd.path.dentry->d_inode, dentry);
+ error = vfs_rmdir(path.dentry->d_inode, dentry);
exit3:
dput(dentry);
exit2:
- mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
- mnt_drop_write(nd.path.mnt);
+ mutex_unlock(&path.dentry->d_inode->i_mutex);
+ mnt_drop_write(path.mnt);
exit1:
- path_put(&nd.path);
+ path_put(&path);
putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
int error;
struct filename *name;
struct dentry *dentry;
- struct nameidata nd;
+ struct path path;
+ struct qstr last;
+ int type;
struct inode *inode = NULL;
struct inode *delegated_inode = NULL;
unsigned int lookup_flags = 0;
retry:
- name = user_path_parent(dfd, pathname, &nd, lookup_flags);
+ name = user_path_parent(dfd, pathname,
+ &path, &last, &type, lookup_flags);
if (IS_ERR(name))
return PTR_ERR(name);
error = -EISDIR;
- if (nd.last_type != LAST_NORM)
+ if (type != LAST_NORM)
goto exit1;
- nd.flags &= ~LOOKUP_PARENT;
- error = mnt_want_write(nd.path.mnt);
+ error = mnt_want_write(path.mnt);
if (error)
goto exit1;
retry_deleg:
- mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
+ mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
+ dentry = __lookup_hash(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
/* Why not before? Because we want correct error value */
- if (nd.last.name[nd.last.len])
+ if (last.name[last.len])
goto slashes;
inode = dentry->d_inode;
if (d_is_negative(dentry))
goto slashes;
ihold(inode);
- error = security_path_unlink(&nd.path, dentry);
+ error = security_path_unlink(&path, dentry);
if (error)
goto exit2;
- error = vfs_unlink(nd.path.dentry->d_inode, dentry, &delegated_inode);
+ error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode);
exit2:
dput(dentry);
}
- mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+ mutex_unlock(&path.dentry->d_inode->i_mutex);
if (inode)
iput(inode); /* truncate the inode here */
inode = NULL;
if (!error)
goto retry_deleg;
}
- mnt_drop_write(nd.path.mnt);
+ mnt_drop_write(path.mnt);
exit1:
- path_put(&nd.path);
+ path_put(&path);
putname(name);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, unsigned int, flags)
{
- struct dentry *old_dir, *new_dir;
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
- struct nameidata oldnd, newnd;
+ struct path old_path, new_path;
+ struct qstr old_last, new_last;
+ int old_type, new_type;
struct inode *delegated_inode = NULL;
struct filename *from;
struct filename *to;
- unsigned int lookup_flags = 0;
+ unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET;
bool should_retry = false;
int error;
if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))
return -EPERM;
+ if (flags & RENAME_EXCHANGE)
+ target_flags = 0;
+
retry:
- from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
+ from = user_path_parent(olddfd, oldname,
+ &old_path, &old_last, &old_type, lookup_flags);
if (IS_ERR(from)) {
error = PTR_ERR(from);
goto exit;
}
- to = user_path_parent(newdfd, newname, &newnd, lookup_flags);
+ to = user_path_parent(newdfd, newname,
+ &new_path, &new_last, &new_type, lookup_flags);
if (IS_ERR(to)) {
error = PTR_ERR(to);
goto exit1;
}
error = -EXDEV;
- if (oldnd.path.mnt != newnd.path.mnt)
+ if (old_path.mnt != new_path.mnt)
goto exit2;
- old_dir = oldnd.path.dentry;
error = -EBUSY;
- if (oldnd.last_type != LAST_NORM)
+ if (old_type != LAST_NORM)
goto exit2;
- new_dir = newnd.path.dentry;
if (flags & RENAME_NOREPLACE)
error = -EEXIST;
- if (newnd.last_type != LAST_NORM)
+ if (new_type != LAST_NORM)
goto exit2;
- error = mnt_want_write(oldnd.path.mnt);
+ error = mnt_want_write(old_path.mnt);
if (error)
goto exit2;
- oldnd.flags &= ~LOOKUP_PARENT;
- newnd.flags &= ~LOOKUP_PARENT;
- if (!(flags & RENAME_EXCHANGE))
- newnd.flags |= LOOKUP_RENAME_TARGET;
-
retry_deleg:
- trap = lock_rename(new_dir, old_dir);
+ trap = lock_rename(new_path.dentry, old_path.dentry);
- old_dentry = lookup_hash(&oldnd);
+ old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags);
error = PTR_ERR(old_dentry);
if (IS_ERR(old_dentry))
goto exit3;
error = -ENOENT;
if (d_is_negative(old_dentry))
goto exit4;
- new_dentry = lookup_hash(&newnd);
+ new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto exit4;
if (!d_is_dir(new_dentry)) {
error = -ENOTDIR;
- if (newnd.last.name[newnd.last.len])
+ if (new_last.name[new_last.len])
goto exit5;
}
}
/* unless the source is a directory trailing slashes give -ENOTDIR */
if (!d_is_dir(old_dentry)) {
error = -ENOTDIR;
- if (oldnd.last.name[oldnd.last.len])
+ if (old_last.name[old_last.len])
goto exit5;
- if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])
+ if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len])
goto exit5;
}
/* source should not be ancestor of target */
if (new_dentry == trap)
goto exit5;
- error = security_path_rename(&oldnd.path, old_dentry,
- &newnd.path, new_dentry, flags);
+ error = security_path_rename(&old_path, old_dentry,
+ &new_path, new_dentry, flags);
if (error)
goto exit5;
- error = vfs_rename(old_dir->d_inode, old_dentry,
- new_dir->d_inode, new_dentry,
+ error = vfs_rename(old_path.dentry->d_inode, old_dentry,
+ new_path.dentry->d_inode, new_dentry,
&delegated_inode, flags);
exit5:
dput(new_dentry);
exit4:
dput(old_dentry);
exit3:
- unlock_rename(new_dir, old_dir);
+ unlock_rename(new_path.dentry, old_path.dentry);
if (delegated_inode) {
error = break_deleg_wait(&delegated_inode);
if (!error)
goto retry_deleg;
}
- mnt_drop_write(oldnd.path.mnt);
+ mnt_drop_write(old_path.mnt);
exit2:
if (retry_estale(error, lookup_flags))
should_retry = true;
- path_put(&newnd.path);
+ path_put(&new_path);
putname(to);
exit1:
- path_put(&oldnd.path);
+ path_put(&old_path);
putname(from);
if (should_retry) {
should_retry = false;
*/
int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
- struct nameidata nd;
void *cookie;
+ struct inode *inode = d_inode(dentry);
+ const char *link = inode->i_link;
int res;
- nd.depth = 0;
- cookie = dentry->d_inode->i_op->follow_link(dentry, &nd);
- if (IS_ERR(cookie))
- return PTR_ERR(cookie);
-
- res = readlink_copy(buffer, buflen, nd_get_link(&nd));
- if (dentry->d_inode->i_op->put_link)
- dentry->d_inode->i_op->put_link(dentry, &nd, cookie);
+ if (!link) {
+ link = inode->i_op->follow_link(dentry, &cookie);
+ if (IS_ERR(link))
+ return PTR_ERR(link);
+ }
+ res = readlink_copy(buffer, buflen, link);
+ if (inode->i_op->put_link)
+ inode->i_op->put_link(inode, cookie);
return res;
}
EXPORT_SYMBOL(generic_readlink);
}
EXPORT_SYMBOL(page_readlink);
-void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd)
+const char *page_follow_link_light(struct dentry *dentry, void **cookie)
{
struct page *page = NULL;
- nd_set_link(nd, page_getlink(dentry, &page));
- return page;
+ char *res = page_getlink(dentry, &page);
+ if (!IS_ERR(res))
+ *cookie = page;
+ return res;
}
EXPORT_SYMBOL(page_follow_link_light);
-void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
+void page_put_link(struct inode *unused, void *cookie)
{
struct page *page = cookie;
-
- if (page) {
- kunmap(page);
- page_cache_release(page);
- }
+ kunmap(page);
+ page_cache_release(page);
}
EXPORT_SYMBOL(page_put_link);
int page_symlink(struct inode *inode, const char *symname, int len)
{
return __page_symlink(inode, symname, len,
- !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS));
+ !mapping_gfp_constraint(inode->i_mapping, __GFP_FS));
}
EXPORT_SYMBOL(page_symlink);
Code Review / kvmfornfv.git / blobdiff