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Merge branch 'work.recursive_removal' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

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Pull vfs recursive removal updates from Al Viro:
 "We have quite a few places where synthetic filesystems do an
  equivalent of 'rm -rf', with varying amounts of code duplication,
  wrong locking, etc. That really ought to be a library helper.

  Only debugfs (and very similar tracefs) are converted here - I have
  more conversions, but they'd never been in -next, so they'll have to
  wait"

* 'work.recursive_removal' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems
This commit is contained in:
Linus Torvalds
2020-02-05 05:09:46 +00:00
parent bddea11b1b a3d1e7eb5a
commit 72f582ff85
9 changed files with 104 additions and 218 deletions
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121
fs/debugfs/inode.c
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@@ -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)
static void remove_one(struct dentry *victim)
{
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;
if (d_is_reg(victim))
__debugfs_file_removed(victim);
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
/**
* 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)
{
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);
}
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