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authorAl Viro <viro@zeniv.linux.org.uk>2019-11-18 17:43:10 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2019-12-11 06:29:58 +0300
commita3d1e7eb5abe3aa1095bc75d1a6760d3809bd672 (patch)
tree1dce9bdc1052f0a94dffe67526e38f5a8202164f /fs/debugfs
parente42617b825f8073569da76dc4510bfa019b1c35a (diff)
downloadlinux-a3d1e7eb5abe3aa1095bc75d1a6760d3809bd672.tar.xz
simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems
two requirements: no file creations in IS_DEADDIR and no cross-directory renames whatsoever. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/debugfs')
-rw-r--r--fs/debugfs/inode.c121
1 files changed, 14 insertions, 107 deletions
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index f4d8df5e4714..bda942afc644 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -332,7 +332,10 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
parent = debugfs_mount->mnt_root;
inode_lock(d_inode(parent));
- dentry = lookup_one_len(name, parent, strlen(name));
+ if (unlikely(IS_DEADDIR(d_inode(parent))))
+ dentry = ERR_PTR(-ENOENT);
+ else
+ dentry = lookup_one_len(name, parent, strlen(name));
if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
if (d_is_dir(dentry))
pr_err("Directory '%s' with parent '%s' already present!\n",
@@ -681,62 +684,15 @@ static void __debugfs_file_removed(struct dentry *dentry)
wait_for_completion(&fsd->active_users_drained);
}
-static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
-{
- int ret = 0;
-
- if (simple_positive(dentry)) {
- dget(dentry);
- if (d_is_dir(dentry)) {
- ret = simple_rmdir(d_inode(parent), dentry);
- if (!ret)
- fsnotify_rmdir(d_inode(parent), dentry);
- } else {
- simple_unlink(d_inode(parent), dentry);
- fsnotify_unlink(d_inode(parent), dentry);
- }
- if (!ret)
- d_delete(dentry);
- if (d_is_reg(dentry))
- __debugfs_file_removed(dentry);
- dput(dentry);
- }
- return ret;
-}
-
-/**
- * debugfs_remove - removes a file or directory from the debugfs filesystem
- * @dentry: a pointer to a the dentry of the file or directory to be
- * removed. If this parameter is NULL or an error value, nothing
- * will be done.
- *
- * This function removes a file or directory in debugfs that was previously
- * created with a call to another debugfs function (like
- * debugfs_create_file() or variants thereof.)
- *
- * This function is required to be called in order for the file to be
- * removed, no automatic cleanup of files will happen when a module is
- * removed, you are responsible here.
- */
-void debugfs_remove(struct dentry *dentry)
+static void remove_one(struct dentry *victim)
{
- struct dentry *parent;
- int ret;
-
- if (IS_ERR_OR_NULL(dentry))
- return;
-
- parent = dentry->d_parent;
- inode_lock(d_inode(parent));
- ret = __debugfs_remove(dentry, parent);
- inode_unlock(d_inode(parent));
- if (!ret)
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ if (d_is_reg(victim))
+ __debugfs_file_removed(victim);
+ simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
-EXPORT_SYMBOL_GPL(debugfs_remove);
/**
- * debugfs_remove_recursive - recursively removes a directory
+ * debugfs_remove - recursively removes a directory
* @dentry: a pointer to a the dentry of the directory to be removed. If this
* parameter is NULL or an error value, nothing will be done.
*
@@ -748,65 +704,16 @@ EXPORT_SYMBOL_GPL(debugfs_remove);
* removed, no automatic cleanup of files will happen when a module is
* removed, you are responsible here.
*/
-void debugfs_remove_recursive(struct dentry *dentry)
+void debugfs_remove(struct dentry *dentry)
{
- struct dentry *child, *parent;
-
if (IS_ERR_OR_NULL(dentry))
return;
- parent = dentry;
- down:
- inode_lock(d_inode(parent));
- loop:
- /*
- * The parent->d_subdirs is protected by the d_lock. Outside that
- * lock, the child can be unlinked and set to be freed which can
- * use the d_u.d_child as the rcu head and corrupt this list.
- */
- spin_lock(&parent->d_lock);
- list_for_each_entry(child, &parent->d_subdirs, d_child) {
- if (!simple_positive(child))
- continue;
-
- /* perhaps simple_empty(child) makes more sense */
- if (!list_empty(&child->d_subdirs)) {
- spin_unlock(&parent->d_lock);
- inode_unlock(d_inode(parent));
- parent = child;
- goto down;
- }
-
- spin_unlock(&parent->d_lock);
-
- if (!__debugfs_remove(child, parent))
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
-
- /*
- * The parent->d_lock protects agaist child from unlinking
- * from d_subdirs. When releasing the parent->d_lock we can
- * no longer trust that the next pointer is valid.
- * Restart the loop. We'll skip this one with the
- * simple_positive() check.
- */
- goto loop;
- }
- spin_unlock(&parent->d_lock);
-
- inode_unlock(d_inode(parent));
- child = parent;
- parent = parent->d_parent;
- inode_lock(d_inode(parent));
-
- if (child != dentry)
- /* go up */
- goto loop;
-
- if (!__debugfs_remove(child, parent))
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
- inode_unlock(d_inode(parent));
+ simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count);
+ simple_recursive_removal(dentry, remove_one);
+ simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
-EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
+EXPORT_SYMBOL_GPL(debugfs_remove);
/**
* debugfs_rename - rename a file/directory in the debugfs filesystem