return result;
}
+EXPORT_SYMBOL(getname_kernel);
void putname(struct filename *name)
{
} else
__putname(name);
}
+EXPORT_SYMBOL(putname);
/**
* check_acl - perform ACL permission checking
* when directory is guaranteed to have no in-lookup children
* at all.
*/
-static struct dentry *__lookup_hash(const struct qstr *name,
- struct dentry *base, unsigned int flags)
+struct dentry *lookup_one_qstr_excl(const struct qstr *name,
+ struct dentry *base,
+ unsigned int flags)
{
struct dentry *dentry = lookup_dcache(name, base, flags);
struct dentry *old;
}
return dentry;
}
+EXPORT_SYMBOL(lookup_one_qstr_excl);
static struct dentry *lookup_fast(struct nameidata *nd)
{
}
/* Note: this does not consume "name" */
-static int filename_parentat(int dfd, struct filename *name,
- unsigned int flags, struct path *parent,
- struct qstr *last, int *type)
+static int __filename_parentat(int dfd, struct filename *name,
+ unsigned int flags, struct path *parent,
+ struct qstr *last, int *type,
+ const struct path *root)
{
int retval;
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
- set_nameidata(&nd, dfd, name, NULL);
+ set_nameidata(&nd, dfd, name, root);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(&nd, flags, parent);
return retval;
}
+static int filename_parentat(int dfd, struct filename *name,
+ unsigned int flags, struct path *parent,
+ struct qstr *last, int *type)
+{
+ return __filename_parentat(dfd, name, flags, parent, last, type, NULL);
+}
+
/* does lookup, returns the object with parent locked */
static struct dentry *__kern_path_locked(struct filename *name, struct path *path)
{
return ERR_PTR(-EINVAL);
}
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
- d = __lookup_hash(&last, path->dentry, 0);
+ d = lookup_one_qstr_excl(&last, path->dentry, 0);
if (IS_ERR(d)) {
inode_unlock(path->dentry->d_inode);
path_put(path);
}
EXPORT_SYMBOL(kern_path);
+/**
+ * vfs_path_parent_lookup - lookup a parent path relative to a dentry-vfsmount pair
+ * @filename: filename structure
+ * @flags: lookup flags
+ * @parent: pointer to struct path to fill
+ * @last: last component
+ * @type: type of the last component
+ * @root: pointer to struct path of the base directory
+ */
+int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
+ struct path *parent, struct qstr *last, int *type,
+ const struct path *root)
+{
+ return __filename_parentat(AT_FDCWD, filename, flags, parent, last,
+ type, root);
+}
+EXPORT_SYMBOL(vfs_path_parent_lookup);
+
/**
* vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair
* @dentry: pointer to dentry of the base directory
return inode_permission(idmap, dir, MAY_WRITE | MAY_EXEC);
}
-/*
- * p1 and p2 should be directories on the same fs.
- */
-struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
+static struct dentry *lock_two_directories(struct dentry *p1, struct dentry *p2)
{
struct dentry *p;
- if (p1 == p2) {
- inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
- return NULL;
- }
-
- mutex_lock(&p1->d_sb->s_vfs_rename_mutex);
-
p = d_ancestor(p2, p1);
if (p) {
inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
inode_lock_nested(p2->d_inode, I_MUTEX_PARENT2);
return NULL;
}
+
+/*
+ * p1 and p2 should be directories on the same fs.
+ */
+struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
+{
+ if (p1 == p2) {
+ inode_lock_nested(p1->d_inode, I_MUTEX_PARENT);
+ return NULL;
+ }
+
+ mutex_lock(&p1->d_sb->s_vfs_rename_mutex);
+ return lock_two_directories(p1, p2);
+}
EXPORT_SYMBOL(lock_rename);
+/*
+ * c1 and p2 should be on the same fs.
+ */
+struct dentry *lock_rename_child(struct dentry *c1, struct dentry *p2)
+{
+ if (READ_ONCE(c1->d_parent) == p2) {
+ /*
+ * hopefully won't need to touch ->s_vfs_rename_mutex at all.
+ */
+ inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
+ /*
+ * now that p2 is locked, nobody can move in or out of it,
+ * so the test below is safe.
+ */
+ if (likely(c1->d_parent == p2))
+ return NULL;
+
+ /*
+ * c1 got moved out of p2 while we'd been taking locks;
+ * unlock and fall back to slow case.
+ */
+ inode_unlock(p2->d_inode);
+ }
+
+ mutex_lock(&c1->d_sb->s_vfs_rename_mutex);
+ /*
+ * nobody can move out of any directories on this fs.
+ */
+ if (likely(c1->d_parent != p2))
+ return lock_two_directories(c1->d_parent, p2);
+
+ /*
+ * c1 got moved into p2 while we were taking locks;
+ * we need p2 locked and ->s_vfs_rename_mutex unlocked,
+ * for consistency with lock_rename().
+ */
+ inode_lock_nested(p2->d_inode, I_MUTEX_PARENT);
+ mutex_unlock(&c1->d_sb->s_vfs_rename_mutex);
+ return NULL;
+}
+EXPORT_SYMBOL(lock_rename_child);
+
void unlock_rename(struct dentry *p1, struct dentry *p2)
{
inode_unlock(p1->d_inode);
if (last.name[last.len] && !want_dir)
create_flags = 0;
inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
- dentry = __lookup_hash(&last, path->dentry, reval_flag | create_flags);
+ dentry = lookup_one_qstr_excl(&last, path->dentry,
+ reval_flag | create_flags);
if (IS_ERR(dentry))
goto unlock;
goto exit2;
inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
- dentry = __lookup_hash(&last, path.dentry, lookup_flags);
+ dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto exit3;
goto exit2;
retry_deleg:
inode_lock_nested(path.dentry->d_inode, I_MUTEX_PARENT);
- dentry = __lookup_hash(&last, path.dentry, lookup_flags);
+ dentry = lookup_one_qstr_excl(&last, path.dentry, lookup_flags);
error = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
retry_deleg:
trap = lock_rename(new_path.dentry, old_path.dentry);
- old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags);
+ old_dentry = lookup_one_qstr_excl(&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(&new_last, new_path.dentry, lookup_flags | target_flags);
+ new_dentry = lookup_one_qstr_excl(&new_last, new_path.dentry,
+ lookup_flags | target_flags);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto exit4;
projects / linux-block.git / blobdiff