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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/tracefs
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/tracefs')
-rw-r--r--fs/tracefs/inode.c114
1 files changed, 11 insertions, 103 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 0caa151cae4e..0ee8c6dfb036 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -330,7 +330,10 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
parent = tracefs_mount->mnt_root;
inode_lock(parent->d_inode);
- dentry = lookup_one_len(name, parent, strlen(name));
+ if (unlikely(IS_DEADDIR(parent->d_inode)))
+ dentry = ERR_PTR(-ENOENT);
+ else
+ dentry = lookup_one_len(name, parent, strlen(name));
if (!IS_ERR(dentry) && dentry->d_inode) {
dput(dentry);
dentry = ERR_PTR(-EEXIST);
@@ -499,122 +502,27 @@ __init struct dentry *tracefs_create_instance_dir(const char *name,
return dentry;
}
-static int __tracefs_remove(struct dentry *dentry, struct dentry *parent)
+static void remove_one(struct dentry *victim)
{
- int ret = 0;
-
- if (simple_positive(dentry)) {
- if (dentry->d_inode) {
- dget(dentry);
- switch (dentry->d_inode->i_mode & S_IFMT) {
- case S_IFDIR:
- ret = simple_rmdir(parent->d_inode, dentry);
- if (!ret)
- fsnotify_rmdir(parent->d_inode, dentry);
- break;
- default:
- simple_unlink(parent->d_inode, dentry);
- fsnotify_unlink(parent->d_inode, dentry);
- break;
- }
- if (!ret)
- d_delete(dentry);
- dput(dentry);
- }
- }
- return ret;
-}
-
-/**
- * tracefs_remove - removes a file or directory from the tracefs filesystem
- * @dentry: a pointer to a the dentry of the file or directory to be
- * removed.
- *
- * This function removes a file or directory in tracefs that was previously
- * created with a call to another tracefs function (like
- * tracefs_create_file() or variants thereof.)
- */
-void tracefs_remove(struct dentry *dentry)
-{
- struct dentry *parent;
- int ret;
-
- if (IS_ERR_OR_NULL(dentry))
- return;
-
- parent = dentry->d_parent;
- inode_lock(parent->d_inode);
- ret = __tracefs_remove(dentry, parent);
- inode_unlock(parent->d_inode);
- if (!ret)
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
+ simple_release_fs(&tracefs_mount, &tracefs_mount_count);
}
/**
- * tracefs_remove_recursive - recursively removes a directory
+ * tracefs_remove - recursively removes a directory
* @dentry: a pointer to a the dentry of the directory to be removed.
*
* This function recursively removes a directory tree in tracefs that
* was previously created with a call to another tracefs function
* (like tracefs_create_file() or variants thereof.)
*/
-void tracefs_remove_recursive(struct dentry *dentry)
+void tracefs_remove(struct dentry *dentry)
{
- struct dentry *child, *parent;
-
if (IS_ERR_OR_NULL(dentry))
return;
- parent = dentry;
- down:
- inode_lock(parent->d_inode);
- 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(parent->d_inode);
- parent = child;
- goto down;
- }
-
- spin_unlock(&parent->d_lock);
-
- if (!__tracefs_remove(child, parent))
- simple_release_fs(&tracefs_mount, &tracefs_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(parent->d_inode);
- child = parent;
- parent = parent->d_parent;
- inode_lock(parent->d_inode);
-
- if (child != dentry)
- /* go up */
- goto loop;
-
- if (!__tracefs_remove(child, parent))
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
- inode_unlock(parent->d_inode);
+ simple_pin_fs(&trace_fs_type, &tracefs_mount, &tracefs_mount_count);
+ simple_recursive_removal(dentry, remove_one);
+ simple_release_fs(&tracefs_mount, &tracefs_mount_count);
}
/**